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Publication numberUS3847262 A
Publication typeGrant
Publication dateNov 12, 1974
Filing dateMar 14, 1969
Priority dateMar 14, 1969
Also published asDE2012091A1
Publication numberUS 3847262 A, US 3847262A, US-A-3847262, US3847262 A, US3847262A
InventorsL Higgins
Original AssigneeDatacq Syst Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Apparatus and attachment for deriving coded signals
US 3847262 A
Abstract
A keyboard-actuated apparatus is described for deriving coded electrical output signals characteristic of the individual characters and markings represented by the several keys of a keyboard-actuated apparatus such as a conventional typewriter. The typewriter is of the kind having a plurality of key-actuated printing hammers that are selectively physically moved to a common printing position during operation, and a single sensing device is located adjacent the common printing position for reading-out respective characteristic marking targets secured to or formed on the printing hammers as the hammers are selectively moved past the sensing device to the common printing position. The sensing device then derives output coded electric signals which are characteristic of the individual characters and markings represented by the keys of the typewriter. By this arrangement, simultaneous printing and encoding of electric output signals, can be achieved. The characteristic marking targets on the respective key-actuated printing hammers preferably include at least two sets of markers representative of upper case and lower case alphabetic letters which are selectively interposed into coacting relationship with the sensing device by the capitalization control of the typewriter. The sensing device may comprise an electro-optic fibre transmitting bundle.
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[4 1 Nov. 12, 1974 1 APPARATUS AND ATTACHMENT FOR DERIVING CODED SIGNALS [751 Inventor: Leonard James Higgins,

Schenectady, NY.

173] Assignec: Datacq Systems Corporation,

Latham, NY.

[22] Filed: Mar. 14, 1969 [211 Appl. No.: 815,247

[52] US. Cl 197/1 R, 197/19, 197/36, 197/188, 197/194, 178/5.4 E [51] Int. Cl B41j'19/00 [58] Field of Search. 197/1 R, 19, 20, 36, 187-189, 197/194; 53/47; 250/223 R; l78/5.4 E

[56] References Cited UNITED STATES PATENTS 3,539,723 11/1970 Mattke 197/36 3,234,331 2/1966 Holstein et a1 197/17 X 3,035,380 5/1962 Leavens 53/47 3,324,301 6/1967 Goldberg 250/223 2,196,166 4/1940 Bryle 95/45 2,350,893 6/1944 Hot'gaard 197/1 2,382,251 8/1945 Parker et a1. 178/17 2,408,754 10/1946 Bush 197/5 X 2,616,983 11/1952 Zworykin et a1 179/1003 2,881,976 4/1959 Greanias 235/61 2,987,249 6/1961 Van Vechten 178/17 X 3,017,463 1/1962 Dlnsmore et a1. 197/98 X 3,018,332 1/1962 Johnson et al t 197/1 X 3,032,163 5/1962 Flieg 197/1.5 3,241,648 3/1966 Stenudd 197/l.5 X

3,476,311 11/1969 Feldman l97/1.6 X 3,519,116 7/1970 Koehn 101/93 X OTHER PUBLICATIONS, IBM Technical Disclosure Bulletin, Vol. 4, No. 7, De-

cember 1961, article by A. C. Thorpe entitled Optical Scanner pages 20 and 21.

Primary Exuminer-Robert E. Bagwill Assistant Examiner-E. H. Eickholt [57 ABSTRACT A keyboard-actuated apparatus is described for deriving coded electrical output signals characteristic of the individual characters and markings represented by the several keys of a keyboard-actuated apparatus such as a conventional typewriter. The typewriter is of the kind having a plurality of key-actuated printing hammers that are selectively physica1ly moved to a common printing position during operation, and a single sensing device is located adjacent the common printing position for reading-out respective characteristic marking targets secured to or formed on the printing hammers as the hammers are selectively moved past the sensing device to the common printing position. The sensing device then derives output coded electric signals which are characteristic of the individual characters and markings represented by the keys of the typewriter. By this arrangement, simultaneous printing and encoding of electric output signals, can be achieved. The characteristic marking targets on the respective key-actuated printing hammers preferably include at least two sets of markers representative of upper case and lower case alphabetic letters which are selectively interposed into coacting relationship with the sensing device by the capitalization control of the typewriter. The sensing device may comprise an electro-optic fibre transmitting bundle.

55 Claims, 26 Drawing Figures PATENTEDHHV 12 I974 3,847262 C 22 25? U INVENTOR BY figy ATTORNEY @ATENTEUW 12 3.847.262 SHEET 2 OF 5 ISO 505 l 5 IS I I S I 505 l S I S I S III I 5 I SOS I S0 S0 ISOSOS I S I S I SOS J IIJII I c-:1 d|s|sosos|s|s|sos PAIENTEUHUV 12 1974 3.847262 SHEET 1&0? 5

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SHEET 50$ 5 82 HGIZA g L FmlzB 1; 84 g W/ :MOTION monon IIOIIOICODEOR IIOIIOICODE'OR OOIOOIOINVERSE OOIOOIOINVERSE 87 FIGIZC as 85 h PC m rL sa monou APPARATUS AND ATTACHMENT FOR DERIVING CODED SIGNALS BACKGROUND OF INVENTION 1. Field of Invention This invention relates to a new and improved keyboard-actuated apparatus for simultaneously printing selected characters and deriving coded electric output signals which are representative of the characters being printed.

More particularly, the invention relates to a keyactuated apparatus such as a conventional typewriter of the kind having a plurality of key-actuated printing hammers that are selectively moved to a common printing position during operation of the typewriter, and to an attachment including characteristic marking targets that are detachably secured to the individual key-actuated printing hammers of the typewriter, and that are selectively read-out by a single sensing device mounted adjacent the common printing position for deriving characteristic coded electric output signals that are representative of the respective characters being printed by the typewriter. The attachment may be in the form of a separately sold article that can be secured to existing typewriters of the kind mentioned above for adapting them to derive the desired characteristic coded electric output signals representative of characters being printed. Alternatively, such equipment may be built into the typewriter at the time of original manufacture thereof.

2. Statement of Prior Art Problems With the continually expanding use of electronic digital computer data processing in all phases of business, government, and education, the need for good, reliable, low cost terminal input equipment to the data processing system has become pressing. Existing computer data terminal equipment is extremely costly and requires special training in order to use the equipment. Because of these characteristics,widespread easy access to computer data processing systems and services just is not a reality;

Under existing conditions, for a small business man to enjoy the benefits of computer data processing, he must first accumulate his data on special forms, cards, etc., that then must be physically transported to a data processing center whereit is converted to a form usable by the computer. Thereafter, the data is processed by the data processing center and the results mailed or otherwise communicated to the customer. In order to provide improved computer data processing services to smaller users at low cost, as well as to improve such services for the larger users, the present invention was devised.

SUMMARY OF INVENTION It is therefore a primary object of this invention to provide a low cost, highly reliable, keyboard-actuated apparatus for simultaneously printing selected characters and deriving coded electric output signals which are characteristic of the characters being printed by the apparatus, and which can be supplied directly to a general purpose digital computer through a dial tone receiver connection, direct wire connection, etc., for storage and subsequent processing by the computer.

Another object of the invention is to provide a lowcost and reliable attachment for use on existing conventional typewriters for cheaply and reliably adapting the typewriter to derive characteristic coded electric output signals simultaneously with the printing of the respective characters, and without involving any special training on the part of the typewriter operator other than that normally required for a typist.

It is a further object of the invention to provide a low cost, digital data message sending device that permits the electrical interconnection of conventional office typewriters to teleprinter message systems such as the Telex or Twix systems.

In practicing the invention, a keyboard-actuated apparatus is provided for deriving coded electrical output signals characteristic of the individual characters and markings represented by the several keys of the apparatus. The apparatus is of the type including a plurality of key-actuated members having portions that are physically moved past a common read-out zone for all of the members upon the respective keys being actuated. Characteristic marking means are formed on the respective key-actuated members on the portions thereof that move past the common read-out point. Sensing means are located at the common read-out point for sensing the respective characteristic markings as they move past the common read-out point and for deriving coded electric output signals which are characteristic of the individual characters and markings represented by the keys of the apparatus. The: apparatus may be a conventional typewriter having a movable carriage and on which a spacing marking member is provided which moves with the carriage. A spacing sensing device is positioned to sense the spacing marking member and derive output electric signals representative of a space in messages being encoded by the typewriter. Preferably, the spacing marking member includes a specially coded beginning of lines marking section which is used to generate a characteristic coded electric output signal indicative of the return of the typewriter carriage to the start of a new line position. Alternatively, if tabulated data is to be processed, a special code character may be transmitted to indicate a column, row or other special arrangement of the data. Where the keyboardactuated apparatus comprises a typewriter, it may simultaneously print and encode the electric output signals. Also, preferably the characteristic marking means on the respective key-actuated member include at least two sets of characteristic markers representative of upper case and lower case alphabetic letters which are selectively interposed into coacting relationship with the sensing device by the capitalization control key of the typewriter. By the provision of a counter, or other similardevice, the cycling of the key-actuated members through a forward and return movement that causes them to pass twice through the common readout zone can be employed to develop redundant coded electric output signals that can be used for parity check purposes. Also, if desired, transmission parity check signals may be generated by the form of the code utilized infabricating the markers.

The invention, in one of its preferred forms, comprises a typewriter attachment for a conventional typewriterof the kind having a plurality of key-actuated printing hammers that are selectively physically moved to a common printing position during operation. Characteristic marking means are provided for the respective key'actuated printing hammer in the form of U- shaped target flags that are detachably secured to the tops of the printing hammers. These target flags include alternate light reflecting and non-reflecting areas which are physically arranged in a desired characteristic coded pattern. The sensing means comprises a commonly located electro-optic device for both illuminating and optically reading-out the characteristic coded patterns of alternate reflecting and non-reflecting areas upon the respective key-actuated printing hammers being selectively moved past the electro-optic read-out device. The electro-optic read-out device may comprise a fibre optic light transmitting bundle having light transmitting and light receiving branches, each having one end commonly positioned to illuminate and readout, respectively, the characteristic coded patterns formed on the target clips that are attached to the printing hammers. The remaining end of the light transmitting branch of the fibre optic bundle is positioned to be illuminated by a source of illumination, and the remaining end of the light receiving branch is positioned to receive light pulses from the target clips, and to direct such light pulses onto the light sensitive surface of a photo-electric cell or other electro-optic converting means. Alternatively, an optical system employing a lens may be used to image a read-out light spot on the characteristic markers, and a fibre optic device employed for light receiving purposes. If desired, the target clips may be made to be readily detachable whereby the characteristic coded reflecting and nonreflecting patterns provided for a respective keyactuated printing hammer can be readily changed for cryptography purposes. The attachment may be in the form of a separately sold article that can be secured to existing typewriters having the characteristics mentioned above for adapting such typewriters to derive the desired characteristic coded electric output signal representative of the characters being printed. Alternatively, the attachment may be built into the typewriter at the time of original manufacture thereof.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and many of the attendant advantages of this invention will be appreciated more readily as the same becomes better understood by reference to the following detailed description, when considered in connection with the accompanying drawings,

wherein like parts in each of the several figures are identified by the same reference character, and wherein:

FIG. 1 is a schematic perspective view of a conventional electric typewriter having an attachment secured thereto constructed in accordance with the invention for deriving coded electric output signals representative of the characters being printed by the typewriter, together with a suitable dial tone receiver connection for supplying the coded electric output signal directly to a general purpose digital computer for storage and subsequent processing;

FIG. 2A is a close-up'perspective view of a portion of the attachment comprising the invention illustrating the manner in which it senses the character being printed;

FIG. 2B is a schematic diagram of the physical parts of the sensing device comprising a part of the attachment;

FIG. 3A is a partial perspective view of a keyactuated member or printing hammer of a conventional electric typewriter, and illustrates a characteristic U- shaped target flag to be secured over the end of the printing hammer;

FIG. 3B is a partial perspective view of the printing hammer shown in 3A after the characteristic coded target has been secured thereon;

FIG. 3C through FIG. 3F illustrate different arrangements for providing'the characteristic coded marking on the typewriter printer hammers;

FIG. 4 illustrates a series of alternate light reflecting and non-reflecting areas arranged in a characteristic pattern to form a code;

FIG. 5 is a schematic diagram illustrating the manner in which the coded targets shown in FIG. 4 are illuminated and read-out in accordance with the invention;

FIG. 6 is an alternative read-out arrangement whereby parallel read-out of the coded marker is achieved;

FIGS. 7A and 7B illustrate alternate schematic circuit diagrams of suitable processing and amplifying circuits for processing the pulsed light signal developed by I the read-out arrangements shown in FIGS. 5 and 6;

FIGS. 8A and 8B illustrate alternative optical arrangements for illuminating the target patterns formed on the typewriter printing hammers;

FIG. 8C is a typical waveform illustrating the nature of the electric signals derived from 8A and 88;

FIG. 9 is a schematic illustration of an alternative form of fibre optic read-out arrangement that provides a dual sided read-out;

FIG. 10 is a more detailed schematic illustration of the read-out arrangement shown in FIG. 9;

FIGS. 11A and 118 form respective side and top views of the characteristic paths followed by the respective printing hammers of a typewriter, and depicts the advantages to be obtained by reason of the dual sided read-out arrangements shown in FIGS. 9 and 10;

FIG. 121A illustrates an alternative form of marking structure utilizing magnetic sensing to derive the coded electric output signals from the typewriting printing hammers;

FIG. 12B illustrates a capacitive read-out arrangement suitable for use in practicing the invention;

FIG. 12C illustrates still a different magnetic type of read-out that can be used in practicing the invention;

FIG. 13 is a schematic, perspective view of a spacing bar member and suitable read-out arrangement for deriving spacing mark signals indicative of a space being encoded by a typewriter adapted in accordance with the invention; and

FIG. 14 is a perspective partially broken-away view of a separate coded signal generator constructed in accordance with the invention, suitable for use in generating special end of block, beginning of paragraphs, end of paragraphs, etc., signals.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 is a perspective view of an overall, low-cost computer input terminal constructed in accordance with the invention. In FIG. 1, a conventional, commercially available typewriter is shown at 11 which may comprise any suitable typewriter, such as an IBM Executive electric or other similar typewriter, for example, having a plurality of keys shown at 12 for actuating respective printing hammers (not shown) that are selectively, physically moved to a common printing position upon selective depression of its respective associated key by a typist operating the machine. The printing hammer in printing out a message being typed, is

moved to a common printing position where it forms or prints a desired character on a piece of paper installed in the machine by pressing against the paper which is backed why a carriage 13 that is moved longitudinally with each actuation of the keys 12 in a well-known manner.

A sensing device shown at 14, which preferably comprises an electro-optic sensing device, is mounted adjacent the common printing position for sensing characteristic coded markers formed on each of the respectivekey-actuated printing hammers of the typewriter, as the printing hammers move past the sensing device 14. The sensing device, which will be described more fully hereinafter, operates to derive a coded electric output signal which is representative of each of the characters being printed by the typewriter. The coded electric output signals thus derived are supplied over an electric connection 15 to a conventional data link such as a dial tone transmitter 16 that allows telephone com pany subscribers to communicate with general purpose digital computers through the medium of conventional, commercial or residential telephone communication systems as indicated by the conventional hand receiver set 17 and 18. The data link transmitter 16 may be any conventional, commercially available data coupler such as the data coupler made available by the Bell telephone system to its subscribers, or equivalent devices, for use in communicating with general purpose digital computers and the like. Briefly, the dial tone transmitter 16 when properly set up, and energized by an input, coded binary electric signal, operates to develop characteristic outputtones which then are transmitted through the telephone receiver hand set 18 to a computer at some central data processing center. At the data processing center, the received signal is reconverted by suitable, known circuitry to the original coded, binary form, and may be supplied directly to the computer memory for storage and subsequent processing, etc.

For the purpose of the present discussion, it will be assumed that the sensing device 14, and the required, associated markers to be described hereinafter, are separate attachments to a conventional, existing typewriter whereby reason of the attachment, the existing conventional typewriter is converted into a computer input terminal. It will be appreciated therefore that substantially no special training is required on the part of an operator of such a converted typewriter, computer input terminal other than that normally required of a typist, and the small amount of competence necessary to set up the dial tone transmitter 16 which is little more than that normally required to operate a conventional hand set telephone. Accordingly, it will be appreciated that no special expertise or training would be required as a result of the use of the attachment made available by the invention. As a normal office routine, upon a secretary typing up a personnel time card, an invoice, a receipt, etc., all that need be done in order to communicate the data to be typed into such a memorandum to a central data processing computer is that she dial the computer station on the telephone, upon obtaining an entry line, place the hand set 18 on the dial tone transmitter 16, properlyaaddress the computer through the dial tone transmitter 16, and then proceed to type in the data to be both printed out by the typewriter, and to be recorded in the computer, simultaneously.

FIGS. 2A and 2B of the drawings illustrate in greater detail a preferred construction of the sensing device 14 and the manner of its mounting relative to the keyactuated printing hammers of the typewriter. As is best shown in FIG. 2A, the sensing device 14 is mounted in a position adjacent the common printing area of the typewriter so that the respective key-actuated printing hammers, shown at 21, pass reasonably close (within about one inch) to the sensing device in travelling up to the printing position on the carriage 13. As is best seen in FIG. 2B, the sensing device 14 in actuality comprises an electro-optic means for both iluminating and optically reading-out characteristic coded patterns of reflecting and non-reflecting areas formed on the sides of the respective printing hammers 21 as will be described more fully hereinafter in connection with FIGS. 3 and 4. In one preferred embodiment of the invention, the electro-optic means comprises a fibre optic light transmitting bundle 22 having a light transmitting branch 23 and a light receiving branch 24. However, if desired, the electro-optic means may be comprised by any fibre of glass or plastic, or glass or plastic rods, or bundles of such elements for transmitting light in the below described manner. Alternatively, the electro' optic means may comprise a lens system as described hereinafter with respect to FIG. 8 or other suitable light transmitting and receiving arrangement. Where it is desired to utilize a fibre optic bundle as the element 22, it may comprise a fibre optic bundle such as that employed in theFotonic sensor instrument manufactured and sold by the Instrument Division of Mechanical Technology, Incorporated, located in Latham, New York, and described in detail in a Bulletin No. 02-100, published and distributed by Mechanical Technology Inc. Generally, (if such is used) the fibre optic bundle 22 is comprised by a large number of extremely small diameter, high quality glass or plastic fibres, which are light conducting members of glass or plastic forming one or'a plurality of filaments or rods that transmit light by reason of the phenomenon of total internal reflection providing for the conduction of light passing into one end and along each fibre by impinging on the walls of the fibre at an angle approaching or greater than the critical angle. The fibre optic bundle 22 functions to transmit light directed onto the ends of each fibre, through the fibre and emits the light at a remote end of the fibre with a minimum loss of intensity. In fibre optic bundle 22, both the transmitting and receiving fibre optic elements are intermixed together in any desired configuration, i.e., with the transmitting bundles in a surrounding concentric ring and the receiving fibre optic elements forming a central core, or vice versa or any other desired configuration. All of the light transmitting fibre optic elements in the bundle are branched off to form the light transmitting branch 23 with the ends of the fibre optic elements comprising branch 23 being disposed adjacent a light bulb 25 that provides a fairly constant light flux. Similarly, all of the light receiving fibre optic elements are branched off from the main bundle 22 to form the receiving branch 24 and the ends thereof are positioned to direct light onto the photosensitive surface of a photocell 26.

In operation, light from source 25 is directed into the ends of the fibre optic elements in the transmitting branch 23 then passesthrough the entire length of the fibre optic elements and is emitted out of the end 22a of the fibre optic bundle. This light is directed against the sides of the key-actuated printing hammers 21 where portions of the light are reflected back due to the presence of a characteristic coded pattern of alternate lightreflecting and non-reflecting areas on the sides of the hammers-as will be described more fully hereinafter in cnnection with FIGS. 3 and 4. As a consequence, as

the pattern is translated past the fibre optic bundle,

electric cell 26 produce a characteristic, coded, digital output signal at the output terminals of the cell, which then is amplified, and/or shaped by a suitable pulse shaping and amplifiercircuit 27, and supplied as an output signal through the dial-tone transmitter arrangement described previously in FIG. ii, or over any other suitable path to the input of a central data processing computer for storage and subsequent processing. It is feasible that for certain installations the ambient lighting conditions will be sufficient to enable optical readout of. the characteristics markers without requiring separate illumination. .In such installation, the sensing means'then'need comprise a receive only" device provided that the poorer signal to noise ratio of such an installation, is. acceptable.

FIG. 3A of the drawings illustrates a basic component part of the invention and comprises a striped target or flag 29 consisting of a surface bearing alternately light reflecting and non-reflecting or minimally reflecting areas or stripes 32 and 31, respectively The stripes are arrangedin acharacteristic coded pattern with a certain dimensional mark-space ratio such that a simreadily secured over the end of a respective keyactuated printing hammer 21 to form the overall arrangement shown in FIG. 3B. The target flags 29 may be fabricated fromsmall strips or angles of aluminum foil, or the like and marked with an appropriate six bit code providing for a binary relationship between the alpha numeric character indicated at 33, formed on the printing face of the printing hammers 21. Target flags 29 may be in the form of U-shaped clips as shown in FIGS. 3A and 3B, or may be a simple strip glued or otherwise affixed to the side of the printing hammers 21. With such an arrangement, it is anticipated that the target flags 29 will be prefabricated in a separate processing step and available for attachment to the printing hammers of the typewriter.

It will be appreciated from a consideration of FIG. 3B taken in connection with FIGS. 2A and 2B that as the respective printing hammers of the key-actuated typewriter are caused to move to the common printing position, the alternately light reflecting and non-reflecting patterns 32 and 31 formed on the sides of the printing hammers will produce characteristic coded output signals in the output of photo cell 26 that are amplified by amplifier 27, and can be supplied directly to the central data processing computer facility for storage and subsequent processing over the dial tone transmitter, etc.

The encoding target flags 29 located on the moving key-actuated printing hammers or other key-actuated members of a similar equipment that move through a common read-out zone may be formed in a variety of ways either prior to attachment to the printing head, or if necessary, they can be formed in place on the keyactuated member. In order to minimize the thickness of the member, or for reasons of producing a more permanent mark, etching or plating of the desired coded pattern of alternate light reflecting and non-reflecting areas can be achieved. If desired, the pattern may be formed byprinting or some other known technique. The use of masks to achieve the desired alternate light reflecting and non-reflecting stripes is believed obvious. Where the target flags are to-be prefabricated and subsequently attached to the printing hammers, aluminum foil or some other similar light reflecting material can be printed, plated, etched or otherwise treated using known photograph techniques for providing accurate masters. The target flags may then be shaped and glued or otherwise secured to the printing hammers. FIG. 3C of the drawing illustrates a method of inplace fabrication where a film mask ofresist materials is sprayed, painted, or otherwise applied to'the head of the printing hammer Zi'to form the desired alternate light reflecting and non-reflecting stripes. FIG. 3D of the drawings'illustrates an arrangement where etching or plating of the'heads of the printing hammers 21 can be achieved while the printing hammers are in place and previously have been masked in the manner shown in FIG. 3C. With this arrangement, an anode connection is formed by a suitable conductive plate 35 secured over the head of the printing hammer and having a connection 36 to a positive source of electric potential. An absorbent pad 37 is provided which is soaked in a suitable electrolyte, and is held in place over the head of the printinghammer 21 by the anode member 35. A suitable cathode connection is provided by the conductor 38 to a source of negative potential to achieve the desired plating or etching on the areas not covered by the film'mask of resist material sprayed or otherwise applied to the head of the printing hammer in the manner shown in FIG.'3C. After plating, the unplated portions may be darkened so as to make them nonreflecting or minimally reflecting, and the plated areas may be polished since they generally will be raised. In the case of etching, the recessed portions due to the etching action can be darkened and the non-etched raised portions polished, however it would be necessary to employ a negative mask if etching is to be used. Other suitable techniques and methods will be suggested to those skilled in the art for forming the coded characteristic patterns of alternate light reflecting and non-reflecting areas on the sides of the printing hammers.

While the embodiments of the invention described hereinbefore have all employed characteristic coded patterns utilizing alternate light reflecting and nonreflecting strips, it is entirely feasible to use a light blocking and light transmitting target on the printing hammer. FIGS. 3E and 3F of the drawings illustrate such arrangements. In FIG. 313, a very thin target flag shown at 41 is employed. The target flag 41 may be formed of a light blocking or opaque material and having a series of slits or apertures 42 formed therein which are arranged in a coded sequence with respect to the light blocking or solid portions of the target flag 41. Alternatively, the target flag 41 may be constructed from a transparent material such as Mylar having a plurality of light blocking or opaque marks formed thereon in a desired coded sequence. The target flags 41 may be fabricated in the shape of a small integral tab suspended from a generally O-shaped ring body portion that may be slipped over the head of the printing hammers 21. With a light transmission arrangement such as shown in either FIG. 3E or 3F, the electro-optic readout means must be modified so that the fibre-optic light transmitting branch is disposed on one side of the target flag 41 and the light receiving branch is disposed on the opposite side. In other respects, the arrangement will function in precisely the same manner as the embodiments described previously.

The target marking means discussed in the preceding description have all been usable either as an attachment for an existing typewriter or other similar keyboard-actuated apparatus although such an arrangement could also be used in the manufacture of original equipment in order that such equipment incorporate the desirable electric signal encoding capability made possible by the invention. FIG. 3F of the drawing illustrates an embodiment of a target marking means wherein suitable characteristic coded openings or slits are formed in the heads of the printing hammers 21 at the time of manufacture thereof for use with a transmission type read-out sensor as described in the preceding paragraph with relation to FIG. 3B of the drawings. Similarly, if desired, the printing hammers 21 could be originally manufactured to include alternate light reflecting and non-reflecting areas in place of the holes or openings 43 at the time of manufacture. The provision of the holes or openings 43 in order to comprise the characteristic coded marking means has the shortcoming of weakening the structural strength of the printing hammer 21, and in addition, the use of such permanent openings does not allow ready interchangeability of the characteristic code target flags for cryptography purposes as will be described more fully here- .inafter. Further, the provision of such holes or openings can greatly increase the cost of manufacture of the part due to the requirement for precise and close spacing of the holes if serial or sequential read-out is to be provided in the manner previously described.

For many of the reasons enumerated above, the preferred arrangement is to employ a separately attached, prefabricated target flag having alternate lightreflecting and non-reflecting areas arranged in a characteristic coded pattern for each of the respective keyactuated printing hammers of the apparatus. Such an arrangement generally will provide better positional tolerance, the ability to read-out the respective keyactuated members from one side or the other or from both sides as will be described hereinafter, and eliminates the need for piercing the member with a consequent weakening of the structure. The necessary target clips or flags may be made precisely and at low cost by printing or etching or plating using well known photographic techniques employing demagnification to pro 10 vide accurate masters or masks, printing plates and the like.

FIG. 4 of the drawings illustrates in greater detail the format or layout of the striped target clips or flags which are employed to form the characteristic coded patterns on the respective key-actuated printing hammers of a typewriter or the like, whether a separate prefabricated or permanently formed flag is employed. As shown in FIGS. 4(a) and 4(b), the flags consist ofa surface bearing alternately light reflecting and nonreflecting or minimally reflecting stripes. The stripes are arranged with a certain dimensional mark-space ratio to provide a desired output binary code sequence (such as a six bit binary code) within the constrains dic tated by the dimensional tolerances of the portions of the key-actuated members where the target flag area is to be formed. As stated earlier, it is important to the practice of the invention in its preferred form that the target areas be located on the portions of the respective key-actuated members which travel through a common read-out zone or point. By satisfying this requirement, only a single sensor need be used in order to develop sequentially, all the coded electrical output signals necessary to encode a message being typed or printed. FIG. 4a shows a typical flag fabricated in any of the manners described above to form a sequence of characteristic light reflecting stripes interspersed with nonreflecting or minimally reflecting areas. For this purpose it is necessary to provide separating spaces marked with a little s intermediate each area or stripe where the presence or absence of a light reflecting surface indicates either a binary one I or a binary zero 0 in the conventionally accepted manner. Thus, if the target flag depicted by FIG. 4a is scanned or otherwise read out in the direction indicated by the arrow, the resultant output signal developed by the photocell and supplied through the amplifier to the computer for storage and subsequent processing would be a binary coded electric signal of the form 100111. FIG. 4b of the drawings illustrates a different signal having the binary form 110100. More elaborate and sophisticated code sequences and/or auxiliary signals obviously can be readily provided in the same manner, if desired or required. In one particular embodiment of the invention, an overall flag area such as that depicted in FIG. 4a would have a typical size of about three-eighths of an inch by three-sixteenths of an inch with the threeeighths inch dimension being divided into 15 regions to form an 3 bit code. With this format, about 3/120 or 1/40 of an inch was required to form a non-reflecting space s, a binary O or a reflecting binary I area, as the case may be, and all of the stripes or areas were equal in dimension. Variations of this format to provide a greater encoding capability, etc., are believed obvious to one skilled in the art.

FIG. 4c of the drawings discloses an alternative coding scheme which does not require the use of s spaces in the coding format. In FIG. 4c the upper figure (i) shows the return-to-zero format previously described with relation to FIGS. 4a and 4b. The waveform of the resultant coded output signal is shown in FIG. 4c (ii).

. FIG. 40 (iii) illustrates a comparable data bearing arrangement using a non-return-to-zero format that pro duces a coded output signal of the: form shown in FIG.

40 (iv). From a comparison of the two formats, it will llll to-zero scheme which allows more information to be packed into a target flag of a given physical size, but which has the same discrimination ability. If desired, other coding schemes could be employed such as those providing contiguous clocking signals, etc., which could be used to advantage under certain circumstances. Additionally, the coding may be in the form of evenly spaced alternate light reflecting (or transmissive) areas and non-reflecting (or non-transmissive) areas where the distance of translation of the movable member past the read-out device or devices serves to develop a characteristic number of output signal pulses, and hence characteristically encodes the resultant output signal.

FIG. 4a of the drawings illustrate a preferred arrangement for distinguishing between lower case letters and upper case letters to be printed out by a respective printing hammer (depicted by the dotted outline box 21) of the typewriter. In the arrangement illustrated in FIG. 4d, it will be noted that the coded pattern of alternate light reflecting and non-reflecting areas are substantially the same with the exception of a capitalization mark (comprised by a reflecting binary l stripe) indicated at 45. The format is such that the space occupied by the area 45 is preserved to indicate the existence of a capital alphabetic letter. Otherwise, the lower case coded pattern is identical to the upper case coded pattern and both will produce binary coded output electric signals similar to that described with relation to FIG. 4a.

Read-out of the respective lower case and upper case letters is achieved in the manner depicted in FIG. 5 of the drawings. The arrangement is such that the coded target flags are positioned on the side of the respective printing hammers at locations where the lower case coded pattern indicated as comprising the upper array in the manner shown in FIG. 4d, normally is caused to be transported past the read-out end 22a of the fibre optic bundle sensor device 22. Upon the typist depressing the capitalization key or control of the typewriter, the respective printing hammer (and accordingly its target flags) is caused to be shifted upwardly so that as the printing hammer moves to the printing position, the upper case pattern of alternate reflecting and nonreflecting stripes is transported past the read-out end 22a of the fibre optic bundle. As a result, the capitalization marker shown at 45 will encode the subsequently produced binary electric output signal in a manner to indicate that the letter represented by the binary output signal is to be capitalized. If the capitalization key or control of the typewriter has not been depressed by the typist, then ordinarily the lower case letter will be sensed and read-out by the fibre optic sensing device. While the arrangement shown in FIG. 5 is preferred, it is also possible to use one, two or more sets of markings to represent upper and/or lower case with or without clock signals and other data associated with each particular key depending upon the circumstances.

In the coded pattern marking and read-out arrangements described hereinbefore, the electrical output signal is in bit-serial form. FIG. 6 illustrates an arrangement whereby the electrical output signal is produced in bit-parallel form. In the FIG. 6 arrangement, the coded target flag 51 that is secured to the side of the printing hammer is provided with longitudinally extending stripes 52 providing appropriately coded alternate light reflecting and non-reflecting or minimally refleeting areas. With this arrangement the target flag will be scanned or read-out in the direction indicated by the arrow 53. To read-out the plurality of longitudinally extending coded stripe 52, a plurality of light transmitting and read-out fibre optic branches 54a-54f are required. The ends of the fibre optic branches 54a-54f are positioned so as to illuminate and read-out the coded pattern of alternate light reflecting and nonreflecting or minimally reflecting areas 52. Light received by the branches 54a54f of the fibre optic bundle 55 is supplied over respective light receiving fibre optic elements 56a-56f and are directed onto the photosensitive surfaces of the respective photoelectric cells 26 a-26f. Light required to illuminate the target flag is supplied from a common source of illumination 25 over light transmitting fibre optic elements that are derived from a common branch 57 and divided or spread out to the various branches 54a-54f.

With the parallel read-out arrangement shown in FIG. 6, the coded pattern formed on the sides of the target flags may be read-out either with the target flag moving past the read-out fibre optic elements 54a-54b (to produce parallel output signal pulses) that then are supplied in parallel to a suitable buffer memory associated with a central data processing computer, or the target flag may be read-out while the target is stationary to produce a level, coded output signal where there is a steady light condition in the case of the reflecting areas and a no-light condition in the case of the nonreflecting areas of the target flag. If it is desired to readout the parallel coded target flag while it is moving, the provision of a start read-out, and stop read-out encoder may be desired. Such a start and stop read-out encoder is shown in FIG. 6 as comprising openings (or reflecting areas) 58 which are positioned so as to be interposed in the optical path between a source of illumination 59 and a photocell 61 whose output is supplied through an amplifier 62 and suitable interconnecting link to the input of the data processing computer to inform it to read-out the parallel encoded signal. Alternately, the computer could be appropriately programmed to interrogate the output of the photocells 26a-26f at an appropriate point in time so that the parallel coded target flags 51 can be properly sampled and read-out during each actuation of a printing hammer of the typewriter. Similar arrangements could be provided to achieve read-out while the target flag is stationary at the instant that the printing hammer hits or prints out a character being typed.

FIG. 7A is a schematic circuit diagram of a suitable photosensitive read-out and amplifying circuit usable in connection with the invention to derive the desired coded electric output signal representative of the respective character of a key-actuated apparatus such as a typewriter. In the circuit arrangement shown in 7A, a suitable photosensitive device 26 such as a photocell, photo-transistor, photo-diode, or some other suitable electro-optic converter is employed. The device 26 is positioned adjacent the output end of the receiving branch of the fibre optic bundle so that light emanating from the end of the fibre optic elements impinges upon the photosensitive surface of the device. The device 26 may comprise a field effect photo'transistor having a source electrode connected to a source of positive voltage and a drain electrode connected to the base electrode of an NPN amplifying transistor 65. The gate of the photo-transistor 26 is connected through a limiting resistor to the tap point 66 of a resistor voltage divider connected across the source of positive voltage. The NPN amplifying transistor 65 has its collector connected directly to the positive terminal of the source of operating potential and its emitter electrode connected through a 560 ohm resistor to the common or ground terminal of the source of operating potential. A zener diode 67 is connected in series circuit relationship with a dropping resistor across the source of operating potential in order to stabilize the voltages applied to the circuit to a given voltage value. Output signals developed by the circuit are obtained from the emitter of the transistor 65 through output terminal 68.

In operation, light flux from the end of the receiving branch 24 of the fibre optic bundle impinges on the photosensitive surface of the photo-transistor 26 to cause a variation in the current flowing between the source and drain electrodes thereof. The magnitude of this variation can be adjusted in accordance with the setting of the tap point 66 on the voltage dividing resistor and the value of the limiting resistor connected between the tap point and the gate electrode of the device. The variation in light flux (which is pulsed in nature due to the alternate reflecting and non-reflecting or minimally reflecting surfaces of the coded target pattern) produces a corresponding pulsed current flowing through the device 26 that is amplified by the transistor amplifier 65, and supplied as a coded pulsed digital output signal at the output terminal 68 connected to the emitter of transistor 65. The invention is in no way limited to use with the particular sensing and amplifying circuit shown in FIG. 7A since this circuit is merely typical of a suitable arrangement for deriving the desired coded electric output signals for supply to the central data processing computer from any of the previously described electro-optic monitors. In the event a parallel bit read-out arrangement such as shown in FIG. 6 is employed, then a multiplicity of circuits such as that shown in- FIG. 7 would be required to process the output signalsdeveloped by each of the photoelectric cells of the parallel read-out arrangement.

FIG. 7B illustrates an alternative amplifying and shaping circuit that is comprised by a light sensitive photo-transistor 26 having'its output connected to the base electrodeof a transistor 69a. Transistor 69a in conjunction with transistor 6% forms a conventional schmidt trigger circuit that serves to better shape the signal pulses derived by the encoder. The output from the schmidt trigger circuit is supplied to a final output amplifying stage comprised by a transistor 70 that amplifies the signal pulses to the usual logic drive level. The shaped and amplified output pulses are then supplied over the data link to the computer for storage and processing.

While it is anticipated that the photoelectric cells, semiconductor photo-transistors, photo-diodes, or other suitable light sensitive devices such as 26 will be designed to respond to visible light, the invention is in no way restricted to the use of visible light. It is known that radiant energy in the form of light covers a visual range extending from red through the various colors to violet, and that this range is bordered by infra-red on one side of the spectrum and by ultra-violet on the other. For certain applications, it may be desirable to employ either infra-red or ultra-violet light in sensing and reading-out the characteristic coded patterns in accordance with the invention, and appropriate modification of the sensing device to accommodate the use of such light energy, is believed obvious to those skilled in the art. Should it be desired, a fluorescent substance could be printed or painted on the sides of the keyactuated members to form the coded target flags or patterns. The patterns thus encoded then could be illuminated and read-out from an ultra-violet light source. While this technique would not necessarily be superior to the techniques previously described employing visible light, such an arrangement would be appropriate where it is desired to keep the encoding on the respective printing hammers secret as in cyphering applications. Such a read-out technique when employed in conjunction with readily removable or detachable target flags or clips such as those described with relation to FIGS. 3A and 38 whereby the target flags are readily replaceable, makes possible the application of the invention in encrypting operations involving the trans mission and processing of secret messages or records.

FIG. 8 illustrates two diagrammatic views of alterna tive optical systems for use in reading-out the coded patterns of alternate light reflecting and non-retlecting stripes on the sides of the printing hammers 21. In FIG. 8A the alternate reflecting stripes 32 are illuminated from a source of illumination comprising a filament lamp 25 set in a tube 25 having a lens 71 set in its end so as to produce a very finely focused spot of interro' gating light (shown at 72) that can be contained completely within the width of the reflecting stripes 32 and- /or the width of the non or minimally-reflecting binary 0 or s stripes. The spot illuminated by the optical systern 71 is viewed by the end 22a of a fibre optical read out bundle 22 which is bent or cranked so as to be oriented toward the image of the lamp filament. The output end of the fibre optic read-out bundle is directed onto the photosensitive surface of a photoelectric cell 26 in the previously described manner. The dotted outline circle shown at 73 illustrates the general area viewed by the fibre optical read-out bundle 22. This circle 73 also depicts the general area of illumination that would be produced by a fibre optic transmitting branch such as that shown at 23 in FIG. 1, should such a fibre optic light transmitting branch be employed in place of the focusing lens arrangement 71. As a result of the use of the focusing lens arrangement 71, an improved output signal can be obtained'from the photoelectric cell 26 having a greatly improved signal to noise ratio. This improved output signal is depicted in FIG. 8C of the drawings wherein the solid line wave form (shown at 74) depicts the nature of the coded output signal obtained from photoelectric cell 26 where both fibre optic light transmitting and fibre optic light receiving branches are employed such as is shown in FIG. 2B. The signal wave form depicted by the dotted line graph 75 illustrates the comparable output signal obtained if the optical system shown in FIG. 8A is used employing a focusing lens 71. This improved output signal is obtained by reason of the fact that substantially all of the light directed toward the target flag im pinges on a light reflecting stripe: 32 and is reflected back to the ends 220 the fibre optic receiving elements in fibre optic bundle 22. From a comparison of the finely focused interrogating light spot 72 to the more diffused, enlarged spot 73 which would be produced by a complete interrogating fibre optic light system using a fibre optic light transmitting branch, it will be appreciated that considerably more light will be reflected into the end 22A of the interrogating fibre optic receiving element 22 from the finally focused spot 72 than would be thecase with the more diffuse spot 73. This increased reflected, light flux results in much more sharply defined and intense received light pulses than in turn produce the improved output signals such as those shown at 75 having a greatly improved signal to noise ratio.

FIG. 8B of the drawings illustrates still another modified form of electro-optical readout means using a source of illumination 25, a focusing lens 71 for focusing light from source 25 into a finally focused interrogating light spot 72 that then is read-out by a light receiving lens system shown generally at 76 for focusing received reflected light from the spot 72 onto the photosensitive surface of the photo-electric cell 26. With an optical system shown in FIG. 88, substantially the same or even better signal to noise ratios can be obtained than those obtained with the arrangement of FIG. 8A.

It is believed apparent that various combinations of the above encoding and electro-optical read-out arrangements may be used economically to gather a wide variety of data using either a uniform or a wide range of data codes from existing keyboard-actuated apparatuses such as conventional electric thpewriter, desk calculators and the like where appropriately coded target flags can be affixed to portions of the respective keyactuated members of the apparatus which move past a common read-out point as in the case of an electric typewriter having a common printing position. With existing apparatuses of this nature, the provision of a fibre opticmonitoring sensor utilizing fibre optic bundles or branches, is preferred over other types of optical systems since the fibre optic elements may be readily positioned adjacent a common printing or read-out position to monitor the target flags without interfering with the normal actuation or operation of the parts of the apparatus, and without bearing on such parts or interfering with their interaction 'in any way. As previously indicated, the target flags may be affixed to either side of the key-actuated members such as the printing hammers of an electric typewriter, with the fibre optic sensor being mounted on whichever side is required, and is most convenient in order to interrogate and read-out the coded target flags. Moreover, it should be kept in mind that the invention is not limited to the modification of existing typewriters or other similar keyboardactuated office machines. An important aspect of the invention is the original inclusion in such machines of a type bar or other similar keyboard-actuated member having a series of printed, embossed or otherwise formed stripes coded in'a pattern to form a target on the side of the striker head or any other convenient member, as on the printing arm bars of a calculator.

FIG. 9 is a schematic diagram of a double sided, fibre optic monitor or sensor that may be used with advantage in practicing the invention. The dual sided, fibre optic monitor shown in FIGS. 9 and 10 is designed to position composite transmit-interrogate and light receiving branches 22a and 22b on both sides of a printing hammer such as shown at 21, and on which suitable coded target flags are formed on at least two sides thereof. The fibre optic branches 22a and 22b comprise a part of a fibre optic bundle 22 having a pair of parallel light transmitting branches 23a and 23b and a pair of parallel light receiving branches 24a and 24b. The ends of the light transmitting branches 23a and 23b are positioned opposite the source of illumination 25 for transmitting light from this source through appropriate light transmitting fibre optic elements that comprise the respective branches 23a and 23b as well as the branches 22a and 22b to illuminate the target flags on both sides of the printing hammer 21. Light reflected from the coded, array of light reflecting stripes and non or minimum-reflecting stripes then is gathered by the light receiving fibre optic elements and transmitted through the respective branches 24a and 24b to the photosensitive surface of the photo-electric cell 26. It will be appreciated therefore that both sides of the coded printing hammer 21 are readout in parallel but that each individual side is read-out serially. As a result, a considerably improved signal to noise ratio is obtained, and any variation in signal level due to lateral misalignment is minimized. This latter feature is extremely useful where it is intended that the electro-optical monitor be transferred from one typewriter in an office to another in order to monitor the cartridge target flag attachments thereon during different operating periods.

FIG. 11 is a diagrammatic sketch illustrating in greater detail the manner in which the dual sided fibre optic read-out arrangement shown in FIGS. 9 and 10 minimizes the effect of lateral misalignment of the typewriter printing hammers. In FIG. 11A, the typewriter roller or carriage is shown at 13, and a respective key-actuated printing hammer 21 is shown passing through a common read-out zone X just prior to striking the roller at the print-out point. In reaching this position, the printing hammer 2i will have travelled over the dotted line path 77 in reaching the common readout position X comprised generally by the space between the pairs of dash dot lines 78-79. FIG. 11b of the drawings is a schematic diagram of the top view of a similar typewriter apparatus wherein the dotted line paths 77a and 77b are intended to illustrate or depict the paths of the outermost key-actuated printing hammers, and which are travelled by such printing hammers in moving to the common print-out position. As best shown in FIG. 11B,.the common read-out zone is disposed between the pairs of dash-dot lines 78-79 and is marked generally by an X. From a consideration of FIG. 11C, it will be appreciated that with respect to a single sided sensor, any one of the respective printing hammers might be disposed laterally one way or the other from a normal median position. This could be due to bending, etc., and would result in either a larger or smaller amplitude signal being read-out by a single sided sensor or monitor. In the case of the dual sided sensor, such lateral displacement of the printing hammers will result in increasing the amplitude of one of the signals being read-out so as to compensate for the decreased amplitude of the opposite signal. As a consequence, lateral displacement of the typewriter hammers is overcome with the dual sided read-out arrangetic coded grooves may be cut, etched, machined or otherwise formed in the sides of the printing hammers of a typewriter, or stripes of material of relatively high magnetic permeability material may be applied to the sides of the printing hammers 21 as shown in FIG. 12A to provide the raised portions 81. These raised portions may be physically arranged in a pattern so as to provide either the code or the inverse of the code depicted below the member 21. With the sides of the printing hammers 21 thus preformed, the characteristic coded raised portions 81 may be read-out with suitable magnetic sensors such as shown at 82 and 83.

With one form of magnetic read-out using an arrangement such as shown in FIG. 12, a direct current energizing current may be supplied to either of the sensorsA or B (it is assumed that either form of sensor will be used but not both), and the variation of inductance in the sensing coil detected by a suitable detecting circuit, and coded pulsed output signals derived therefrom for use in the previously described manner. This variation in inductance will be due to the variation in the air gap intermediate the core of the sensing coil arrangement 82 or 83 and the magnetically permeable member 21. having the coded raised portions 81.

Alternatively, a direct current energizing signal may be applied to either of the coils 82 or 83, and the induced alternating current component due to the variation in flux linkage, is detected. This variation in flux linkage will be caused by the relative motion of the lines of force of the field, and hence flux linkage, with the excitingwinding (or a secondary pickup winding provided forthe purpose of detecting the induced alterhating current component). This induced alternating current component can then be detected, shaped and employed in deriving the desired coded electric output signals. Still another alternative magnetic detecting scheme using a sensing arrangement such as that shown in FIG. 12A could be provided by exciting either the coil 82 or coil 83 with an alternating current of relatively high frequency, and then sensing the relative loss due to variation in the eddy current loss induced by virtue of the'coded raised portions 8t. All of these alternative magnetic detection schemes employ sensing methods which are well known, but would require modification or original manufacture of the printing hammers of the keyboard-actuated apparatus to provide appropriate impressions or raised portions 81 forming the required code patterns.

Still another well known detection technique can be employed in practicing the invention as depicted in FIG. 12B of the drawings. In utilizing the technique shown in FIG. 128, the printing hammer head, or other comparable key-actuated member, again would have to be modified to provide the varying level or raised portions such as8l that are arrayed in accordance with the desired code. With this arrangement, a capacitive readout head 84 is provided which is excited with a high frequency alternating current electric signal. With this arrangement, the change in capacitance due to the coded raised portions 81 can be sensed by a suitable detecting circuit coupled to the capacitance read-out head 84 for use in deriving the desired coded output signal corresponding to the code embodied in the raised portions 81.

FIG. 12C of the drawings illustrates still another alternative magnetic detecting scheme employing magnetizable stripes of material. In this arrangement, alternate stripes of magnetizable material and non-magnetizable areas are formed on either side (or both sides) of the respective type bar printing hammers by means of highly permeable material deposited or otherwise formed in accordance with a predetermined coded pattern. The material may comprise a square loop hysterisis material such as iron oxide used in the manufacture of magnetic tapes or disc recording devices. One way of forming the desired coded pattern of alternate magnetizable and non-magnetizable areas is to remove from an iron oxide coated milar recording tape, the negative of the code sequence to be detected. The resulting structure may then be secured by any known means to the sides of the respective hammers to provide a coded pattern of magnetizable regions intermixed with non-magnetizable regions such as shown at in FIG. 12C.

In order to read-out the coded pattern of magnetizable regions 85., a permanent magnet or direct current energized electromagnet 86 is provided which will serve to magnetize the stripes 85 upon the printing hammer 21 being moved in the forward or printing direction as depicted by the arrow 88. Immediately adjacent the magnetizing coil or permanent magnet 86 is a magnetic detecting head 87 which will produce an output pulse as the flux from the magnetized stripes 85 interlinks its turn during passage of the printing hammer 21 past the detecting coil 87. The pulsed electric output signals thus produced may then be amplified and supplied directly to a central data processing computer for storage and subsequent processing. Alternatively, the magnetic detecting head 87 may comprise a combined read-write magnetic detecting head which will serve to magnetize the alternate magnetizable stripes 85 as they pass thereunder on the: forward or printing stroke of the printing hammer 21., and thereafter the same head can be employed to read-out the magnetized stripes as they pass by on the return stroke. If a highly retentive magnetizable material is used in forming the regions 85, it would also be possible to reverse the pro cess whereby on the return stroke the magnetizable stripes are magnetized, and then read-out on a subsequent forward or printing stroke.

Front the preceding description of the alternative detection schemes that may be employed in practicingthe invention, it will be appreciated that basically all of these schemes invoke the novel idea of using a single read-out point or zone for a keyboard-actuated apparatus such as an electric typewriter wherein the identity of the selected key-actuated member determined by the key depressed, is interrogated. In all of these schemes, the alignment of the interrogating means is not critical and may even be easily detachable from the apparatus. Interrogation is achieved dynamically while the key-actuated member is travelling to and returning from its printing position without requiring that the member be held in a stationary fixed period for any interval of time for the purpose of interrogation. The novel system proposed here is superior in the provision of the features of positional tolerance, the ability to interrogate the target flags from one side or the other, or both sides if desired, and the elimination of the need for piercing or otherwise weakening the structure of the printing hammers, etc. Of the methods and assemblies proposed for practicing the invention, the interrogation by means of reflected light pulses conveyed by a fibre optic bundle is preferred in that the signals may be induced and detected easily with less complexity of apparatus. Also the coded target flags may be made precisely and at low cost by use of known printing, etching, plating, methods and using known photographic techniques to provide accurate masters or masks, printing plates and the like. Further, the fibre optic read-out bundle may be introduced into confined spaces since it occupies only a very small volume, and the fibre optic elements comprising the bundle may be intertwined or otherwise positioned around objects which otherwise might constitute barriers to the installation of the sensor. This is in contrast to other arrangements which might require the installation of wound components, optical lens, systems, or other devices in locations which are quite confined or not previously designed to accommodate such elements. Further, the use of the fibre optic sensor allows the photocells, amplifiers, source of illumination and other signal processing logic and circuitry to be positioned at a point remote from the common interrogating point with a minimum of difficulty and alteration to existing equipment being modified to include the electric output signal encoding feature.

- When the invention is employed in conjunction with a keyboard-actuated apparatus such as a typewriter; it may prove desirable to provide an auxiliary function generator such as shown in FIG. 14 of the drawings for the purpose of supplying to the central data processing computer certain auxiliary instructions such as end of message characters, block instructions, end of record characters, start of paragraphs, end of paragraphs, and the like. This can be accomplished with the assembly shown in FIG. 14 without the need for an operator to memorize special code character sequences. The assembly is comprised of a plurality of push buttons or keys 91 supported on a housing 92 by means of return springs 93 and suitable bearing supports (not shown). The respective keys 91 are connected through a reciprocally'movable shaft member 94 to a target flag 95 having a characteristic coded pattern of intermixed reflecting and non-reflecting or minimally reflecting areas formed thereon by any of the previously described techniques. The reciprocally movable target flags 95 are viewed by an auxiliary branch 96 of the main fibre optic'bundle employed in the overall monitor and includes transmit and receive branches 96a and 9611, respectively. Each of the respective auxiliary push buttons or keys 91 are provided with a similar optical read-out arrangement for reading out the particular auxiliary instruction message encoded thereon.

With the arrangement shown in FIG. 14, it is possible for a typist as he or she is typing a message on a conventional typewriter adapted to incorporate the present encoding arrangement to merely depress an appropriate push button or key 91 that is properly identified as the beginning of a new paragraph, end of a paragraph, etc. Upon this occurrence, the target flag 95 attached to that particular auxiliary message encoding key will be scanned past its associated fibre optical read-out branch 96, and will generate the characteristic code message that can be supplied to the computer along with the message being typed to indicate any of the above listed auxiliary functions. Further, if desired the auxiliary function keys 91 can be used to monitor other machine functions such as depression of the space bar. Also, if desired, the auxiliary function generator could be employed to indicate the selection or use of upper Eli case letters in place of the dual encoding arrangement described with respect to FIG. dC of the drawings.

It should be noted that with respect to both the auxiliary function generator shown in FIG. 14, and a conventional electric typewriter which has been adapted to incorporate the invention, the encoded electrical output signal can be derived and transmitted either at the time that the key is depressed or upon its release or on both occasions (i.e., either or both forward and return reading is possible). In the event a reading is desired in only one direction, the reading may be provided in either the forward or return direction, with the messsage being blanked in the opposite direction of movement. A certain improvement and facility of use may be achieved by incorporating blanking into the monitor amplifier, or alternatively by appropriately programming the central data processing computer such that the encoded output signal pulses are gated only with the key or other monitored parts travelling in the go" or printing direction. The arrangement would be such that transmission of the code with the member travelling in the return direction, is suppressed. Although the return transmission is suppressed, it is desirable to provide a local control unit incorporating a bit counter (not shown) or other known equivalent comparison means for code character comparison purposes. With such an arrangement, the bit characters generated with the key or other monitored parts travelling in the go or printing direction can be compared to the bit characters read in the reverse or return direction for read verification or parity check purposes. Alternatively, transmission parity check signals could be generated by the form of the code utilized on the target flag.

FIG. 13 of the drawings illustrates a special typewriter motion function generator for monitoring motion of the typewriter carriage 13 during the typing out of a message. This typewriter motion function generator is comprised by an elongated spacing character or marking member shown generally at 97 which is supported on and moves with the typewriter carriage 13. The spacing marking member 97 is encoded with a plurality of light reflecting blank or space shift" characters indicated at 98, for example, which are repeated along the length of the elongated member 97 with a pitch equal to one typewriter space. The spacing char acter marks 98 are monitored by an auxiliary branch 99 of the main fibre optic bundle having transmit and receive branches 99a and 99b for monitoring the spacing character bar 97 in the manner previously described. The receive branch 99b of the fibre optic bundle 99 may be arranged to direct its light output onto a special photoelectric converter for developing separately encoded electrical spacing output signals that then may be combined with the main character output signal generated by the monitor through suitable logic circuitry and supplied to the central data processing com puter for storage and subsequent processing.

It is also preferred that a special beginning of line series of characteristic markers be encoded at one end of the member 97 (for example, the left-hand end). By thus fabricating the spacing character marking member 97, each time that the carriage 13 is returned to its initial starting position (which is generally associated with the beginning of a new line in a message being typed), the specially encoded marking characters will serve to appropriately encode the spacing marking output sigriage shifts following the transmission of a typed or printed character during the character blanking period, and will also transmit a beginning of line indicator whenever the typewriter carriage returns to its initial starting position indicating the special beginning of a line in a message being typed and encoded. As an alternative to this arrangement, special beginning of line codes, column or row codes, etc., could be provided in the form of special character keys, and then transmitted along with the data being typed out Another desirable feature embodied in the invention is the provision or inclusion of a lockout or preventive means for avoiding simultaneous encoding of two characters whose keys may have been concurrently hit accidentally by the typist. This feature has long been built into most conventional electric typewriters such that in the event of accidental hitting of two keys of the typewriter, the printing head of only one of the keys will be allowed to travel to and print out its respective character. Because the necessary lock-out controls to achieve this function has long been known in the art, and currently are being used on most office machines of the type under consideration, it is believed unnecessary to describe such controls in detail. It is essential however to the proper electrical encoding of typed messages, that the commonly located read-out or monitoring device (i.e., the fibre optic bundle and associated parts) be located at some point such as X shown in FIG. 11A where it can appropriately sense the marking target flags on all of the respective printing hammers. It is also essential that the read-out location be positioned at a point subsequent to the discriminator action of the typewriter lock-out control where as a result of the functioning of the lock-out control only one printing hammer has been allowed to travel beyond the control point and past the monitor. For example, if the lock-out control operates in a manner to prevent two of the printing hammers'to travel more than one quarter or say one half of the arcuate path from their initial rest position to the common printing position as shown in FIG. 11A, then the common read-out point of the sensor should be located subsequent to the control point where this control action takes place. In this manner,

any ambiguity that might be generated as the result of the accidental hitting of two or more keys simulta- All of the arrangements are such that the alignment of the interrogating means with the respective keyactuated members is not critical, but nevertheless provides reliable electrical encoding of the identity of a character being typed or printed. The invention may be designed so that it is easily attached to and detached from such a keyboard-actuated apparatus, or it may be permanently incorporated into the equipment at the time of original manufacture. The novel systems herein proposed are superior in the matter of positional tolerance, the ability to interrogate from one side or the other, or both sides of the respective key-actuated members, and the elimination of the need for piercing the respective members thereby structurally weakening them. Of the several detecting methods proposed for interrogating the key-actuated members, the novel arrangement of interrogation by means of transmitted and reflected light conveyed by a fibre optic bundle is believed superior in that the sensor may be more readily accommodated into existing equipment and reliable electrical signal enncoding can be accomplished more easily with less complexity. Additionally, the target flags to be employed in conjunction with the fibre optic bundle sensor arrangement can be made precisely and at low cost by known photographic, etching or plating techniques. Further, the use of the fibre optic bundle allows the associated light source, photoelectric cell, amplifier and/or other signal processing circuitry all to be remotely located from the normally critically located common read-out position without any substantial sacrifice in performance since the fibre optic bundle may be easily intertwined into and around obstacles in being led from the locality of the common read-out position to a less critical area where the photocell, amplifier, etc, can be mounted.

it will be appreciated, therefore, from the foregoing description that the invention provides a new and improved keyboard-actuated apparatus, such as a conventional typewriter, of the kind having a plurality of key-actuated members, such as the printing hammers of a typewriter, that are selectively moved to a common printing position during operation of the apparatus, and to an attachment to the apparatus including characteristic marking, coded target flags that may be permanently formed on or detachably secured tothe individual key-actuated members or printing hammers. These coded target flags are selectively read-out by a single sensing device mounted adjacent the common printed position for deriving characteristic coded electrical output signals that are representative of the respective characters identified by the keys of the keyboard. The

' assembly may be in the form of aseparately sold attachment that can be secured to existing typewriters, or other similar office equipment of the kind mentioned above for adapting them to derive the desired characteristic coded electrical output signals representative of the characters being printed. Alternatively, such equipment may be built into the machine at the timeof original manufacture.

Having described several embodiments of a keyactuated apparatus and attachment for deriving coded electrical output signals representative of characters being typed or printed constructed in accordance with the invention, it is believed obvious that other modifications and variations of the invention are possible in the light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined in the appended claims.

What is claimed is:

1. A keyboard-actuated apparatus for deriving coded electrical output signals characteristic of the individual characters and markings represented by the several keys of the apparatus and including a plurality of keyactuated members having portions that are physically moved past a common read-out zone for all of the cally coupling'all of the characteristic markings of the respective key-actuated members to the electro-optic sensing means in a serial manner as they are physically moved past the common read-out zone.

2. A keyboard-actuated apparatus according to claim 1 wherein the electro-optic sensing means further comprises a single light emitting element and fibre optic coupling means for directing light from the light emitting element' onto the characteristic markings to enhance read-out.

3. A keyboard-actuated apparatus according to claim 2 wherein the electro-optic sensing means comprises unitary fibre optical coupling means serially viewing all of the characteristic markings as they are physically moved past the unitary fibre optical coupling means and for directing light emanating from the illuminated characteristic markings. onto a photosensitive device for converting the light pulses into corresponding electrical pulses.

4. A keyboard-actuated apparatus according to claim 1 wherein the keyboard apparatus includes means for moving the. key-actuated members through a forward and return-movement that causes them to pass twice through the common read-out zone upon actuation, said electro-optic sensing means serving to develop two coded electric output signals one of which is redundant in response to the forward and return movements of the key-actuated members.

5. A keyboard-actuated apparatus according to claim 1 wherein the characters are alpha-numeric characters and the apparatus comprises a typewriter including a vmovable carriag e; spacing marking means secured to and movablewiththe carriage and spacingsensing means positioned to sense the marking means and derive output electric signals representative of a space in messages'being encoded by said keyboard actuated apparatus for use along withthe coded output electrical signals derived by said apparatus. 7 6. A keyboard-actuated apparatus according to claim tively interposed into operative relationship with the electro-optic sensing means by the capitalization control key of the typewriter.

'8. A keyboard-actuated apparatus according to claim 7 wherein the keyboard apparatus includes means for movingthe key-actuated members through a forward and return movement that causes them to pass twice through thecommon read-out zone upon actuation, said electro-optic sensing means serving to develop two coded electric output signals one of which is redundant in response to the forward and return movement of the key-actuated members.

9. A keyboard-actuated apparatus according to claim 8 wherein the electro-optic sensing means comprises a single light emitting element and fibre optic light coupling means for directing light from the single light emitting element onto the characteristic markings.

10. A keyboard-actuated apparatus according to claim 9 wherein the electro-optic sensing means further comprises fibre optic light coupling means for transmitting light emanating from the illuminated characteristic markings to a single photosensitive element for converting the light pulses into corresponding electrical pulses.

11. A keyboard-actuated apparatus according to claim 10 further including an auxiliary keyboardactuated device for developing characteristic auxiliary function coded output electrical signals usable along with the coded output electrical signals developed by the main keyboard actuated apparatus to enhance the intelligence conveying capability of the overall system.

12. A keyboard-actuated apparatus according to claim 10 wherein the characteristic marking means is provided only on one side of the key-actuated member and a single electro-optic sensing means is provided at the common read-out point for serially reading out the single side of the key-actuated member having characteristic marking means provided thereon. I

13. A keyboard-actuated apparatus according to claim l0 wherein characteristic marking means are provided on at least two sides of the respective keyactuated members and the electro-optic sensing means comprises a dual sided sensing means for simultaneously sensing the characteristic marking means on each of the two sides of the respective key-actuated members with only a single photo sensitive element.

14. A keyboard-actuated apparatus according toclaim 1 wherein characteristic marking means are provided on at least two sides of the respective keyactuated members and the electro-optic sensing means comprises a dual sided sensing means for simulta- ,l

neously sensing the characteristic marking means on each of the two sides of the respective key-actuated .members with only a single photo-sensitive means.

15. A keyboard-actuated apparatus according to claim 1 wherein the characteristic marking means are permanently formed on the key-actuated members at points which move past the common read-out zone upon the respective members being actuated.

16. A keyboard-actuated apparatus according to claim 1 wherein the characteristic marking means comprises a'separate attachment having the characteristic markings formed thereon and that can be secured to and removed from the key-actuated members of the apparatus at a location thereon which moves past the common read-out zone upon the respective members being actuated for changing the encoding.

17. A keyboard-actuated apparatus according to claim 1 wherein the characteristic marking means on the respective key-actuated members comprise alternate light reflecting and non-reflecting elongated striplike areas physically arranged in a desired characteristic coded pattern, and the electro-optic sensing means comprises a single source of light for illuminating and a single electro optical pick up device for optically reading-out the characteristic coded patterns of reflecting and non-reflecting elongated strip-like areas upon the areas being moved past the view of the electrooptic means in a direction transverse to the elongated dimension of the strip-like areas.

18. A keyboard-actuated apparatus according to claim 17 further including a fibre optic light transmitting branch having at least one end commonly positioned to view and read-out the characteristic coded patterns of the respective key-actuated members and at least one remaining end positioned to direct light pulses onto the light sensitive surface of the single electro- .ing end positioned to be illuminated by the source of light and to direct light pulses received from the characteristic marking means onto the light sensitive surface of the single electro-optical pick-up device, respectively.

20. A keyboard-actuated apparatus according to claim 19 wherein the key-actuated members have characteristic light reflecting and non-reflecting patterns formed on at least two sides thereof and the fibre optic light transmitting and light receiving bundle comprises a dual-sided fibre optic bundle having at least two light receiving fibre optic elements positioned to view and read-out simultaneously the respective patterns on each of the sides along substantially the same single optical light path andto transmit the received coded light pulses to the light sensitive surface of the single electrooptical pick-up device.

21. A keyboard-actuated apparatus according to claim 19 wherein the attachment comprises target flags which can be secured to and removed from the keyactuated members whereby the characteristic coded reflecting and non-reflecting encoding patterns provided for respective key-actuated members can be readily changed.

22. A keyboard-actuated apparatus according to claim 1 whereinthe characteristic marking means on the respective key-actuated members comprise alternate light reflecting and non-reflecting elongated striplike areas physically arranged in a desired characteristic coded pattern, and the sensing means comprises electro-optic means for illuminating and optically reading-out the characteristic coded patterns'of reflecting and non-reflecting elongated strip-like areas upon the respective key-actuated members being selectively actuated and the areas being moved past the view of the electro-optic means in a direction transverse to the elongated dimension of the strip-like areas, said electro-optic means comprising at least a source of illumination, means for directing light from said source of illumination onto the characteristic coded reflecting and non-reflecting patterns of the respective key-actuated members, light receiving means for receiving light reflected from the coded patterns on the respective keyactuated members, and a single electro-optic converting device having the light output from said light receiving means directed thereon for converting the intelligence contained in the received alternate pulses of reflected light into coded electrical signals which are characteristic of the individual characters and markings represented by the keys of the apparatus.

23. A keyboard-actuated apparatus according to claim 22 wherein the means for directing light and the light receiving means comprises a fibre optic bundle having light transmitting and light receiving branches each having one end commonly positioned to illuminate and read-out, respectively, the characteristic coded patterns of the respective key-actuated members and each having a remaining end positioned to be illuminated by the source of illumination and to direct light pulses received from the characteristic marking means onto the light sensitive surface of the electrooptic converting device.

24. A keyboard-actuated apparatus according to claim 23 wherein the characteristic light reflecting and non-reflecting patterns are formed on at least two sides of the respective key-actuated members and the light receiving means comprises a dual-sided fibre optic bundle having at least two light receiving fibre optic branches positioned to view and read-out simultaneously the respective patterns on each of the two sides along substantially the same single optical light path and to transmit the received coded light pulses to the light sensitive surface of the electro-optic converting device.

25. A keyboard-actuated apparatus according to claim 22 wherein the characteristic markingmeans on the respective key-actuated members includes at least two sets of characteristic markers representative of upper case and lower case alphabetic letters which are selectively interposed into operative relationship with the electro-optic sensing means by the capitalization control.

26. A keyboard-actuated apparatus according to claim 25 wherein the keyboard apparatus includes means for moving the key-actuated members through a forward and return movement that causes them to pass twice through the common read-out zone upon actuation, said electro-optic sensing means serving to develop coded electric output signals one ofwhich'is redundant in response to the forward and return movements of the key-actuated members.

27. A typewriter attachment for a conventional typewriter of the kind having a plurality of key-actuated printing typeheads that are selectively physically moved to a common printing position during operation, said attachment serving to derive coded electric output signals from the typewriter during operation and comprising target flags having serially arrayed characteristic marking means formed thereon for attachment to the respective typeheads, and a single read-out electrooptical element having a single light path optically coupling the single read-out electro-optical element to the target flags after attachment to the respective typeheads for serially reading-out all of the characteristic marking means on the respective typeheads as the typeheads are selectively moved past the common printing position and deriving output coded electric signals which are characteristic of the individual characters and markings represented by the keys of the typewriter.

28. A typewriter attachment according to claim 27 further including spacing marking means having a characteristic mark for each space in a line extending across the typewriter carriage and adapted to be secured to and movable with the typewriter carriage, and spacing sensing means positioned to sense the spacing marking means and derive output electric signals representative of a space in messages being encoded by the typewriter for use along with the coded output electrical signals derived from the typeheads of the typewriter, the spacing marking means including specially coded beginning of line markers which generate a characteristic coded electric output signal indicative of the return of the typewriter carriage to the start of a new line position.

29. A typewriter attachment according to claim 27 wherein the characteristic marking means on the respective typeheads includes at least two sets of characteristic markers representative of upper case and lower case alphabetic letters which are selectively interposed into operative relationship with the sensing means by the capitalization control key of the typewriter.

v30. A typewriter attachment according to claim 27 wherein the keyboard apparatus includes means for moving the key-actuated typeheads through a forward and return movement upon actuation that causes them to move twice past the common sensing means, said sensing means serving to develop coded electric output signals one of which is redundant in response to the forward and return movements.

31. A typewriter attachment according to claim 27 wherein the target flags having the characteristic marking means formed thereon for attachment to the respective key-actuated typeheads include alternate light reflecting and non-reflecting elongated strip-like areas physically arranged in a desired characteristic coded pattern, and the single read-out electro-optical element comprises at least a source of illumination, means for directing light from said source of illumination onto the characteristic patterns of the respective key-actuated typeheads, light receiving means for receiving light reflected from the coded patterns on the respective keyactuated typeheads, and a photosensitive converting element having the light output from said light receiving means directed thereon. 1

32. A typewriter'attachment according to claim 31 wherein the light receiving means comprises a fibre optic light transmitting element having at least one end commonly positioned to view and read-out the characteristic coded patterns of the target clips on the respective key-actuated printing hammers and a remaining end positioned to direct received light pulses onto a single light sensitive surface of the photosensitive converting element.

33. A typewriter attachment according to claim 31 wherein the means for directing light and the light receiving means comprises a fibre optic light transmitting bundle having light transmitting and light receiving branches each having one end commonly positioned to illuminate and read-out, respectively, the characteristic coded patterns of the target flags on the respective keyactuated printing typeheads and each having a remaining end positioned to be illuminated by the source of illumination, and to direct light pulses received from the target clips onto the light sensitive surface of the photosensitive converting element, respectively.

34. A typewriter attachment according to claim 31 wherein the target flags have characteristic light reflecting and non-reflecting patterns formed on at least two sides thereof and the light receiving means comprises a dual-sided fibre optic bundle having at least two light receiving fibre optic branches positioned to view and read-out simultaneously the respective patterns on each of the sides and to transmit the received coded light pulses to the light sensitive surface of the photosensitive converting means.

35. A typewriter attachment according to claim 31 wherein the target flags are detachable whereby the characteristic coded reflecting and non-reflecting patterns provided for a respective key-actuated printing typehead can be secured to and removed from the typeheads for changing the encoding.

36. A typewriter attachment according to claim 31 wherein the characteristic marking means on the respective typehead target flags includes at least two sets of characteristic markers representative of upper case and lower case alphabetic letters which are selectively interposed into operative relationship with the sensing means by the capitalization control key of the typewriter.

37. A typewriter attachment according to claim 31 wherein the light receiving means comprises a fibre optic light transmitting element having at least one end commonly positioned to view and read-out the characteristic coded patterns of the target flags on the respective key-actuated typeheads and a remaining end positioned to direct received light pulses onto a light sensitive surface of the photosensitive converting element.

38. A typewriter attachment according to claim 31 wherein the means for directing light and the light re ceiving means comprises a fibre optic light transmitting bundle having light transmitting and light receiving branches each having one end commonly positioned to illuminate and read-out, respectively, the characteristic coded patterns of the target flags on the respective keyactuated typeheads and each having a remaining end positioned to be illuminated by the source of illumination, and to direct light pulses received from the target flags onto the light sensitive surface of the photosensitive converting element, respectively.

39. A typewriter attachment according to claim 38 wherein the target flags have characteristic light reflecting and non-reflecting patternsformed on at least two sides thereof and the light receiving means comprises a dual-sided fibre optic bundle having at least two light receiving fibre optic branches positioned to view and read-out simultaneously the respective patterns on each of the sides and to transmit the received coded light pulses to the light sensitive surface of the electro-optic converting element.

40. An attachment for a conventional key-actuated typewriter for converting the key-actuated typewriter to derive a coded electric output signals which are representative of each of the several characters and markings formed on the keys of the typewriter, said attachment comprising a detachable clip designed to be secured to a respective movable member of the typewriter which is physically moved in response to the actuation of a respective key of the typewriter, said detachable clip having alternate light reflecting and nonreflecting elongated strip-like code marks physically arranged in a desired serially arrayed characteristic coded pattern and adapted to be mounted on the movable members so as to move the alternate elongated strip-like code marks in a direction substantially per-

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Classifications
U.S. Classification400/104
International ClassificationG06F3/042, H03K17/972, G06F3/033, H03K17/969, B41J3/51
Cooperative ClassificationH03K17/972, H03K17/969, B41J3/51, G06F3/0304
European ClassificationG06F3/03H, H03K17/969, H03K17/972, B41J3/51