|Publication number||US2866855 A|
|Publication date||Dec 30, 1958|
|Filing date||Jan 22, 1957|
|Priority date||Jan 22, 1957|
|Publication number||US 2866855 A, US 2866855A, US-A-2866855, US2866855 A, US2866855A|
|Inventors||Forest Louis Z La|
|Original Assignee||Mc Graw Edison Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (6), Classifications (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Dec. 30, 1958 L. z. LA FOREST 2,865,855
DICTATING MACHINES Filed Jan. 22, 1957 2 Sheets-Sheet 2 United States yPatent DICTATING MACHINES Louis Z. La Forest, Parsippany, N. I., assignor to McGraw-Edison Company, Elgin, Ill., a corporation of Delaware Application January 22, 1957, Serial No. 635,222 8 Claims. (Cl. 179 100.1)
This invention relates to dictating machines and more particularly to improvements-in such machines by which the indexing of length, correction or other indications for the benefit of the transcriber is made directly on the record itself.
My invention is concerned especially with dictating machines of the type which operate in connection with a magnetizable record such as a flexible, elongate sheet or web comprising a non-magnetic backing coated with magnetizable material; however, no unnecessary limitation of my invention to dictating machines of this type is intended.
It is the usual practice to provide phonographic machines ,adapted especially for recording dictation with means by which the user can make registrations in a spatial relationship to the positioning of the recording head on the record to indicate for the benefit of the transcriber points on the reco-rd whereat lengths and corrections are made, the term Alengths being used herein to mean points on the record where separate items of dictation are started and ended. Typically, theseregistrations have been made in the -form of visible marks on a so-called indexing slip separate from the record itself. This requires that each index slip be attached to the respective record or that each slip and record be suitably marked so that one will not become lost from the other during the handling of the records as between the user and transcriber. Additionally, this prior procedure involves `the ditliculty of having to separately mount and remove the index slips bo-th with respect to the recording and transcribing machines. To circumvent these diiiiculties I herein provide new and improved di'ctatin'g machines and records whereby the indexing indications are made directly on the records themselves.
An object of my invention is accordingly to simplify the use of dictating and transcribing machines particularly as to the indexing operations involved in connection therewith.
Another object is to provide for the Vindexing on unused or border portions of the records themselves.
Another object is to provide indexing registrations in the form of spot recordings on a magnetizable record medium.
Another object is to provide novel arrangements for making indexing registrations along unused border portions of llexible magnetic records in accordance with the positioning of the recording head on the record.
Another object is to provide for indexing along. the border of a sheet record which during use is supported in the form of a closed loop.
A further object is to provide anovel mechanism for moving an indexing head `over an unused portion 'of a record in accordance with the traveling movement of the recording head across the record.
These and other objects and features of my invention will be apparent from the following description andthe appended claims.
2. In the description of my invention reference is had to the accompanying drawings, of which:
Figure l is a fractional plan view of the operating mechanism of a sheet record type of dietating machine in which my invention is incorporated; I
Figure 2 is a fractional vertical view with parts in section on the line 2 2 of Figure 1, showing, also the housing partly in section and partly broken away;
Figure 3 is a fractional section taken on the line 3 3 of Figure 1; y y
Figure 4 is a fractional sectional view taken approximately on the line 4 4 of Figure 1; l
Figure 5 is a vertical sectional view taken on the line 5 5 of Figure 1;
Figure 6 is a vertical section taken on the line 6 6 of Figure 5;
Figure 7 is a plan view to enlarged scale of the indexing head as it appears in Figure 1 but showing' the coils in cross section; n
Figure 8 is a fractional sectional view as seen from the line 8 8 of Figure 5, showing the indexing head in its operating position on the record; l
Figure 9 is a diagrammatic view of circuits and apparatus showing a way of selectively energizing the indexing head; Y, y I n Figure 10 is a'view of'a magnetic sheet recordforuse in the sheet record machine herein described showing however the central portion of the Asheet record 'broken awawand Figure ll is a plan view illustrating the mode of'usin'g my invention in connection with a magnetic VVrecordii'ig machine of the type which records transversely of the direction of advance of the record medium. l l Y By 4way of preferred illustration, I show onefernbodi ment of my invention in connectionwith a sheet record magnetic recording and reproducing machine v10 as illustrated in Figures l-lO. This machinemay have a base plate 11 provided with two side standards 12 and 13 secured thereto by suitablelug and Yscrew arrangements as illustrated in Figures 3 and 4. These standards have bearings 12a and 13a for a shaft "14 `carrying a reco-rd support in the form of a drum 15. The drum is rotated in a countercloekwise direction as it appears in Figure 2 by a suitable drive mechanism comprising a kwheel 16 mounted on one end of the shaft 14 and coupled as by a belt to a motor (not shown). At the front of theV drum there is a box-like carriage 17 open at the front and back. This carriage has bearings 1S in its side walls which embrace slidably a tubular cross rod 19, and has also rectangular openings 20 in its side walls through which passa solid cross rod 21 for holding the carriage inan upright position about the support rod 19. The ends of the tubular rod 19 pass through openings in the side standards and are received in anged capjrnembers 22a and 22b secured as by screws 23 to the Ioutersides of the standards 12 and 13 respectively. The ends of the solid crossrod 21 are received in bearings vin the `side standards to permit rotation of thisV rod as will appear. Pivoted at 24 to the upward rearward portion of the carriage is a depending U-lever 25.- This lever carries a cross rod on its lower end portion on whichis centrally pivoted a vertically-extending equaliz'ingy lever 27. Mounted on the upper and lower ends of 'this equali'zing' lever are amagnetic erase head 28 and a magnetic recordreproduced head 29 having their gaps in vertical alignment with each other. A tension spring 30 biases the lever 25 rearwardly to provide the desired pressure of the heads against the record as will appear.
^ The carriage is`driven along the drum by a feed screw 31 extending axially through the tubular support rod 19. At its rightward end this feed screw isjournalled on a conical thrust bearing 32 threaded through the end cap 22b and held in place by a lock nut 33, and at its leftward end the feed screw passes through a central bearing hole in the end cap 22a. Secured to the outer leftward end of the fed screw is a pinion gear 34 forming part of a gear train comprising an intermediate gear 35 journalled on a standard 36 upstanding from the base 11 and a drive gear 37 integral with the drive wheel 16. On the carriage is a circular feed nut 38 having a hub 38a journalled on a vertical shaft 39 extending slidably through a bearing hole in the lower wall of the carriage and having a head 40 at its upper end threaded into an opening in the upper wall ofthe carriage. The hub 38a bears frictionally against the lower wall of the carriage under pressure of a helical compression spring 41 between the hub`and the head 40. Adjustment of the degree of compression of this spring, to set the desired frictional restraint on the feed nut 38, is made by turning the head .40 by the desired amount and then locking the same in place by a lock nut 42. The circular feed nut 38 passes through a clearance slot 43 in the tubular support rod 19 and meshes permanently with the feed screw. Due to the frctional restraint on the feed nut, rotation of the feed screw which occurs during rotation of the drum 15 causes the carriage to be moved progressively along the drum. However, upon exerting force on the carriage sufficient to overcome this frictional restraint, the carriagecan be otherwise moved. Such other movement may be effected manually as through a bracket 44 secured to the top of the carriage and having an upstanding arm passing through a clearance slot in the housing and terminating in a fngerpiece 45; and alternatively such other movement may be effected in a step fashion as by a suitable ratchet mechanism (not shown) operating on a large gear 46 secured to the hub of the feed nut 38.
The drum 15 is covered peripherally by a tubular sleeve 47 of a resilient material such as rubber to provide a yieldable backing for a rectangular sheet record 48 to be mounted thereon in wrap-around relation thereto. The sheet record has drive holes 49 in its leading corner portions engageable by respective radial drive pins 50 on the end portions of the drum to provide for drive of the sheet record with the drum as the drum is advanced. The sheet record is mounted by sliding the same, leading edge first, through a` slot 51 which extends from `the front-of the machine along the bottom thereof, to a position whereat the drive holes 49 are directly below the drum. When the sheet record reachessuch loading position and the drum is advanced, the drive pins 50 will first flex the corner portions of the sheet record downwardly-which is permitted due to'cutaways 52 in `the bottom wall of the slot 51 as shown in Figure l-until the pins come into registration with thedrive holes, whereupon the corner portions will ex upwardly and become attached to the drum. Upon further advance of the drum, the sheet record is carried therewith in wrap-around relation thereto with the trailing edge comingeither 'in substantial abutment with or overlapping relation to the leading edge of the record. ln order Lto confine the mounted sheet record closely to the drum, the bottom wall of the slot 51 has a guide extension 53 leading around the drum at a clearance distance therefrom to a line directly above the erase head 28 whereat it is fastened to a bracket 54 on the frame or housing. The opening thus provided at the front of the drum is to provide access of the heads 28 and 29 to the mounted sheet record. Below the lower head 29 there is a guide block 55 at a clearance spacing from the drum which has an edge S6 `for engaging the underside of the trailing edge of a mounted sheet record and guiding u the same `outwardly through the` slot 51 when the drum is turned in a reversedirection. t
Upon operating the machine after mounting the sheet record on the drum,` the heads 28 and `29 are 'moved progressively along the drum astthe drum is rotated to define a helical track on the sheet recordpwith the erase `head engaging the `track in advance of the record `head to 4 erase any prior recording that may be on the record. This recording will extend over the area of the sheet record from nearly one drive pin 50 to the next. During reproducing the erase head is disabled and the head 29 is connected to the input of the audio amplifier 57 shown diagrammatically in Figure 9. The audio circuits for feeding signal energy to and from the recorder or reproducer head during recording and reproducing need not however be herein described.
In accordance with my invention, the indexing registrations made by the user for the benefit of the transcriber are recorded on the record sheet itself instead of being made on the usual separate index slip. In this connection I provide the record sheet with a free border space 48u of suitable width along the length of the sheet beyond the left drive hole as shown in Figure 10. The length and correction indications are made by a dual magnetic recording head 58 which is moved along the border 48a in correspondence with the movement of the carriage 17 along the drum. The head may comprise, for example, a core 59 having the usual outer legs and having also a central leg 60 which meets with the outer legs at their polar ends to define two air gaps 61 and 62 displaced along the central leg. Field coils 63 and 64 are mounted on the outer legs for providing a flux flow across their respective gaps. The head is mounted horizontally on a carriage 65 rotatable about the drum shaft 14 with the gaps 61 and 62 engaging the border 48 of the sheet record and defining two side-by-side tracks thereon. Although these tracks are not visible, they are indicated by the lines 66 and 67 in Figure 10.
The carriage 65 is in the form of a circular housing open at its inner end and made of an insulating material such as Bakelite. This housing has a metal hub 68 journaled on an extending sleeve 69 of the bearing 12a and provided with a drive gear 70 at one end. The head 58 has an apertured lug 71 extending obliquely from the bacl; end thereof which is pivoted by a pin 72 to a bifurcated radial lug 73 formed on the carriage Within the circular contour thereof by providing the carriage with a flat 74. This fiat cuts through the outer wall 65u of the housing to `form a side clearance opening 75 therein for the head stru-cture as shown in Figure l. Under pressure of a spring 76 which biases the head 58 inwardly, the pole gaps 61 and 62 of the head bear against the border 48a of the mounted sheet record with the desired pressure.
The indexing carriage 65 is controlled by a planetary gear system comprising a gear 77 abutting against the left end wall of the drum 15 and secured to a sleeve 78 which is interposed rotatably between the shaft 14 and the bearing 12a. Engaging the gear at diametrically opposite sides thereof are two gears 79 rotatably mounted on opposite end portions of a yoke 80 itself secured at its Center to a hub 81 journalled on the sleeve 78. The gears 79 are also in permanent engagement with a surrounding internal gear 82 rigidly mounted on the end of the drum 15. Secured to the yoke 80 is a gear 83 which meshes with a gear 84. The gear 84 is secured to one end of a shaft which is journalled in the lower end portion of a stationary arm 85 the upper end of which ernybraces a reduced diameter end portion of the bearing sleeve 69 and is rigidly staked thereto. Secured to the other end of the shaft of the gear 84 is a gear 86 which meshes with the gear 70 on the carriage 65.
The sleeve 78 carrying the gear 77 of the planetary gear system at its inner end is itself rotated in accordance with the transverse movement of the carriage 17 along the drum. This isaccomplshed by a gear 87 secured tothe outer end of the sleeve 78 and constituting part of a gear train comprising also an intermediate gear 88 journalled at 89 to the side standard 12 and a gear 90 meshing with the latter and secured to the rod 2l. The rod 21 is provided with a long, spiral groove 91 extending throughout the length of travel of the carriage 17. This groove is engaged by a stationary pin 92 on the carriage gewest secured as to the bracket 44. The spiral groove 91 is to be rotated through approximately 2% revolutions as the .carriage 17 is moved through its full length of travel. The central gear 77 of the planetary gear system is turned in correspondence with the rotation of theV rod 21 through the gear train 90, 88and 87 (Figure 3),-'and the sleeve 78 (Figure 5).k If the Agear 77 is turned 3 full revolutions, `the yoke 80 is turned 3A of 1 revolution. Such revolution of the yoke will impart l full revolution to the indexing carriage 65 because the booster train formed by the gears 83, 84,86 and.70 has a ratio of 4:3. However, since a movement of theV carriage 17 throughoutV its full length of travel causes the rod 21 t'o be turned somewhat less than 3 full revolutions, the indexing head 58 will traverse somewhat less than the full length of the free border portion 48a of the mounted sheet record as indicated by the track lengths in Figure l0. On the other hand, a rotation of the drum itself will not impart any movement to the indexing head 58 relative thereto because if the carriage 17 is assumed to be stationary, the gear 77 is also stationary to cause the yoke 80 to be turned of l revolution as the drum is turned l full revolution. Such 3A turn of the yoke is stepped up by the booster train to impart lfull revolution to the indexing head. Therefore, during operation of the machine when both the drum is rotated and the carriage 17 is concurrently moved along the-drum, the indexing head .58 is turned with the drum and is concurrently advanced l.slowly relative to the drum at Such rate as to make nearly 1 revolution relative to the drum as the carriage is m-oved through its full length of travel. By a suitable initial setting of the gears in the planetary gear system the iridexing head 58 is located near the drive pins 50 when the carriage 17 is in an initial or starting position. The
-movement of the indexing ,head is therefore alongy approximatel'y the full length of the sheet record without crossing the joint between the leading and trailing edges thereof. The positioning of the indexing head 58 along the border of the sheet record is therefore always in corvrespondence with the positioning of the recording head across the sheet record.
Indexing registrations are made at points along the border 48a yof the sheet record by momentarily exciting either coil of the head '58 with a surge current. This surge current may be a momentary D. C. pulse or it may be a surge of oscillatory current. For purposes of simplification I obtain such surge current from the audio amplifier by momentarily opening its input circuit to `cause the amplifier to become self-excited and have a high level of noise or hum output, and by concurrently feeding this output to one or the other of the indexing coils. For example, as shown in Figure 9, there are length and correction control buttons marked L and C respectively, which are pivotally interconnected by a rocker 93 itself pivoted at its center on a pivot stud 94 carried by the frame or housing. These control buttons extend loosely Vthrough respective openings in the housing as shown. The L and C buttons have insulating tips 95 at their lower ends for operating respective banks 96 and 97 of switch blades. When the buttons are in their released positions, as shown, the dictators transducer 98 operating as a microphone is connected through contacts 99 of bank 96, lead 100, contacts 101 of bank 97, lead 102, contactk 103g and pole 103 of record-reproduce switch 104 shown in record position, and lead 105 to the input of the audio amplifier 57. At the sarne time the output of the amplifier is connected through lead 106, pole 107. and contact 107a of record-reproduce switch 104, lead 108, contacts 109 of bank 97, lead 110, contacts 111 ofbank 96 and lead 1,12 to record-reproduce head 29, it being understood that the other side of eachV of these circuits isk grounded as designated. However, upon pressing the L button, the blade 111a of switch 111 is broken from its respective contact and pressed against the opposite contact 113 to thereupon open contacts 99 through the switch insulating bar 114. The opening of switch 111 and closing of associated blade 11161 with contact 113 disconnects the amplifier. output from the recordreproduce head 29 and connects the same to the coil 63 of the rotating indexing head 58 through one of two collector rings designated R in Figure 1. The subsequent opening of the contacts 99 has the effect of open-circuiting the amplifier input to place the amplifier in an instable condition causing it to have a high-level output. Therefore, any momentary pressing of the L button has the effect of making a spot recording on the length marking track `66 of the sheet record. Similarly, upon pressing the C button, the blade 10911 of switch 109 is broken from its associated contact and is pressed against the opposite contact 11S to thereupon open the contacts 101 through the switch insulating bar 116. The openings of the switch 109 and closing of the associated blade 109:1 with the contact 115 disconnects the amplifier output from the record-reproduce head 29 and connects the same to the coil 64 of the rotating indexing head 58 through the other of the collector rings R. The subsequent opening of contacts 101 opens the amplifier input circuit to cause the amplifier to have a high-level output. Thus, any momentary pressing of the C button causes the indexing head to make a spot recording on the correction marking track 67 of the sheet record.
When the record-reproduce switch 104 is operated to its reproduce position the pole 103 is shifted to its coritact 103b and the pole 107 to its contact 107b, the effect of which is to reverse the connections of the amplifier with respect to the transducer 9S now actingk as a receiver and the head 29 now acting as a reproducer.
When ever a transcriber desires to read the indexing record she will shift the record-reproduce switch 104 to reproduce position, move a slide 117 which is between the L and C buttons beneath that button corresponding to the track 66 or 67 which is to be read, and press that button and thereupon'shift the carriage 17 through its travelling range. The effect of so moving the slide 117 is to limit the pressing of the L or C button to an intermediate position causing the input of the ampliiier to be shifted from the head 29 to the indexing head 58 but not permitting the amplifier output circuit to be broken by the switch contacts 99 or 101. For instance, upon shifting the slide 117 below the L butto-n and then pressing this switch, the switch 111 is opened and the blade 111a is closed with the contact 113 but the contacts 99 are not disturbed. The coil of the indexing head 58 is thereby connected to the arnplifier input due to the record-reproduce switch 104 4being now in reproduce position, and the amplifier output is connected to the transducer 98 acting as a receiver. As the marriage is then moved to' sweep the indexing head past an indexing spot on the reco-rd, a blurp will be heard from the receiver 98 to inform that the user had made an indexing registration at the point then occupied by the record-reproduce head 29 on the record. Such point will be identified by the positioning of the rear edge of the fingerpiece 45 relative to a scale S on the cabinet along the path of the carriage at the back of the fingerpiece.
in Figure l0 there is illustrated the application of my invention to a magnetic transversal machine of the type disclosed, for example, in Marzocchi Patent No. 2,245,- 286, issued June l0, 1941. Such machine need not be herein described other than to say that it operates ou a magnetic record medium 118 in the form of a long web having drive holes 119 in its border portions for driving engagement with a sprocket type of drive wheel. During operation the web is advanced slowly either continuously o-r in a step manner, vand at the same time the web is traversed crosswise by one or more recording heads which record along successive tracks indicated by the lines 120. In adapting my invention to this machine the web is provided with a suitably wide border i positions therealong corresponding `read by conditioning the machine as before described `with reference` to Figure 9 and advancing or backspacing the web past the indexing head'then acting as a reproducer. n
Although I have hereinparticularly shown and dcscribed my invention in connection with certain specific machines, it will be understood that no unnecessary lmitation is intended thereby since my invention is subject to changes and modifications without departure from the `scope thereof, which I endeavor to express according to the following claims:
I claim: l. In a dictating machine having means for supporting `a record, a record-cooperable recording head mounted for movement transversely of a supported record, and drive means for advancing said record support and concurrently transversely moving said recording head for causing said head to scan a major portion of a supported record while leaving thereon a free border portion: the combination of an indexing head engageable with said border portion; means mounting said indexing head for movement along said border portion in the direction of advance of the record; means responsive to said transverse movement of said recording head for causing said indexing head to be moved along said border portion in proportion to said scanning movement; and means for momentarily energizing said indexing head for making indexing registrations on said border portion at to respective points of scanning on the record. i
2. In a dictating machine having moving means for supporting a record, a record-cooperable recording head, and drive means for advancing said supporting means in one direction and concurrently imparting a relative movement between `said head and supporting means in another' direction to cause said head to scan a portion of the supported record while leaving a free portion thereon extending in the direction of advance of said supporting means: the combinatton of an indexing head mounted to engage said free portion of the record; means for causing said indexing head to be moved relative to the supported record in the direction of advance of the supporting means and in proportion to the scanning movement of said recording head relative to the record; and means for selectively energizing said indexing head to cause the same to make indexing registrations on the record corresponding to selected scanning positions of the recording head on the record.
3. In a dictating machine: the combination of means for advancing a record; a recording head and carriage therefor; means for moving said carriage transversely of the direction of advancement of the record to provide for recordation in a scanning .path over a `major portion of the record while leaving a free border portion thereon; an indexing head positioned to engage said border portion; means for causing said indexing head to be moved along said border portion on a track transverse to the direction of said carriage movement and in accordance with said scanning movement; and means for selectively energizing said indexing head to make indexing registrations at positions along said border portion corresponding to the respective positions of said recording head along said scanning path 4. The combination set forth in claim 1 including an audio amplier for amplifying signals to be fed to said recording head, including means for self exciting said amplier to cause the same to produce a voltage surge and for simultaneously feeding said voltage surge to said `indexing head.
5. Inl a magnetic record machine having a revolvable record support for carrying an elongate magnetic record in wrap-around relation thereto: the combination of a recording head; a carriage for said head movable in a path transversely of the direction of advance of said support; drive means for rotating said support and concurrently advancing said carriage to scan a portion of a mounted record while leaving a free border portion along one side edge of the record; an indexing head engaging 'said border portion; a carriage for said indexing head mounted to provide for movement of the indexing head peripherally along said record support; and coupling means between said indexing head carriage and said recording head carriage for causing the former to move approximately one revolution around said support as the latter is moved across the recordable space of a mounted record.
6. In a phonographic record machine having a rotatable record support for carrying a record thereon: the combination of a recording head; a carriage for said head movable in a path over said support; drive means for rotating said support and concurrently advancing said carriage to scan a portion of a mounted record while leaving a free border portion along one edge of the record; a record-cooperable translating head engaging said border portion; a carriage for said translating head ,mounted for movement of the latter along said border portion; a planetary gear system provided on the shaft of said support for normally carrying said translating head with the support as the support is rotated; and means 4,coupling said planetary gear system to said recording head carriage for providing a movement of said translating head is an indexing head provided with two gaps spaced from each other for making indexing registrations in either of two side-by-side tracks on said free border portion of a mounted record; separate coils in said indexing head for said respective gaps; and an energizing circuit selectively operable for activating either of said coils.
8. In a phonographic machine including a rotatable support for a record and a record-cooperable translating head: the combination of a carriage for said head mounted for a traveling movement causing said head to scan said record as said support is rotated; an auxiliary recordcooperable device mounted for movement about the journal axis of said support along an annular portion of said record; and a drive mechanism for said auxiliary head comprising a planetary gear system including a central gear journaled at said axis and coupled to said carriage to cause the gear to rotate in correspondence with the traveling movement of the latter, an outer concentric gear carried by said record support, a lever journaled on said axis, a planetary gear between said inner and outer gears journaled onto said lever, and a gear train between said lever and said auxiliary device having a stepped-up gear ratio adapted to cause said auxiliary device to be moved in correspondence with said record support when said carriage is at standstill and to be moved relative to said support as said carriage is moved through its path of travel.
References Cited in the tile of this patent UNITED STATES PATENTS
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2188650 *||Apr 23, 1938||Jan 30, 1940||Rca Corp||Magnetic recording|
|US2242803 *||Jun 28, 1939||May 20, 1941||Soundscriber Corp||Correction marker for disk record dictating machines|
|US2709204 *||Oct 28, 1949||May 24, 1955||Stromberg Carlson Co||Recording and reproducing apparatus and methods|
|US2736776 *||Jun 2, 1951||Feb 28, 1956||Armour Res Found||Magnetic recorder head assembly|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3040135 *||Sep 26, 1957||Jun 19, 1962||Mc Graw Edison Co||Dictating machines|
|US3131844 *||Feb 5, 1962||May 5, 1964||Ampex||Transducing apparatus|
|US3295117 *||Mar 21, 1963||Dec 27, 1966||Bell Telephone Labor Inc||Position sensing apparatus|
|US3370283 *||Mar 4, 1964||Feb 20, 1968||Wiltek Inc||Tape transport for an incremental tape recorder|
|US4410923 *||Jan 9, 1981||Oct 18, 1983||Dictaphone Corporation||Display apparatus for recording and/or playback device|
|USRE32342 *||Jul 26, 1984||Jan 27, 1987||Dictaphone Corporation||Instruction indicating apparatus for a record and/or playback device|
|U.S. Classification||360/72.2, 369/27.1|