US 3201961 A
Description (OCR text may contain errors)
Aug. 24, 1965 H, v, w|| |AMs ETAL 3,201,961
CONTROL DEVICE Filed March L2e. 1962 4 Sheets-Sheet 1 A T TOE/VE YS H. v. WILLIAMS ETAL 3,201,961
CONTROL DEVICE 4 Sheets-Sheet 2` JSN U DAN/EL T H/NDA//AN BY M4412@ Q/ @m ATTORNEYS INVENTOR. HOLLA/VD V. W/LL///I//S and Aug. 24, 1965 Filed March 26. 1962 A118. 24, 1965 H. v.w|| 1AMs ETAL 3,201,961
CONTROL DEVICE 4 Sheets-Sheet 3 Filed March 26. 1962 INVENTOR. HOLLA/VD M W/LL//MS and DAN/EL 7.' H/A/DM/V n mmwbmr.
u8- 24, 1965 H. v. WILLIAMS ETAI. 3,201,961
CONTROL DEVICE Filed March 26. 1962 4 Sheets-Sheet 4 BY DAN/EL THM/DM/ United States Patent O 3,201,961 CONTRQL DEVICE Holland V. Williams, Buffalo, and Daniel T. Hindman, Kenmore, NSY., assignors to Finger Keys, Inc., Buffalo, NX.
Filed Mar. 26, 1962, Ser. No. 182,588 lli Claims. QCi. 70--277) This invention relates generally to the control art. More specifically, it is particularly concerned with the contr-ol of a member, for example a door, in response to the presentation of a skin surface having a pre-selected pattern.
Residential and commercial doors are customarily provided with key-operated locks. While such key locks serve their intended purpose admirably, they do possess certain disadvantages. The necessity of using a key to gain admittance is highly inconvenient when the person desiring admittance does not have his hands free to reach for his key and manipulate it in the lock. It also is inconvenient to the person who carries a large number of keys and must try them one by one, in the dark, until he finds the right one.
In addition to the annoyance and inconvenience resulting from these situations, which are all too common, particularly around the home, there is a potential danger and loss of security, particularly in commercial applications where several employees are provided with keys giving them access to particular areas. The necessity of passing out a large number of keys makes it likely that one or more of them will be lost, or perhaps fall into the hands of an unscrupulous person, whereby the key lock does not provide the degree of security intended. Indeed, it is often necessary to provide a watchman, or take even more elaborate precautions, because of this factor.
Accordingly, the primary object of our invention is to provide a control system, for unlocking doors and the like, which can be operated only by one or more predetermined individuals, and which does not require the use of a key or other separate lock manipulating device carried by such individuals.
Another object of our invention is to provide a control device, for doors and the like, which is operable automatically upon presentation of a fingertip having a preselected, distinguishing pattern.
Still another object of our invention is to provide a door control device for unlocking a door automatically upon presentation of a fingertip having a particular, distinguishing pattern, which can be used in conjunction with a conventional key lock to permit operation by means of a key as well as by presentation of a particular lingertip pattern.
In one aspect thereof, a door control system constructed in accordance with our invention is characterized by the provision, in combination with a door control member, of means operating the control member automatically in response to a pre-selected ngertip pattern, the operating means including means for scanning a fingertip and generating a first signal corresponding to the pattern thereof, means for simultaneously scanning a reference fingerprint and generating a second signal corresponding to the pattern thereof, and means responsive to correspondence f the first and second signals for operating the door control member only upon substantial identity between the two patterns.
In another aspect thereof a door control system constructed in accordance with our invention is characterized by the provision, in combination with a door control member, of means for operating the control member automatically in response to a pre-selected fingertip pattern including a test station located adjacent the door for presentation of a fingertip by a person desiring to control Patented Aug. 24, 1965 the door, together with means for scanning a fingertip presented at the test station and generating a first signal corresponding to the pattern thereof, means for simultaneously scanning a reference fingerprint and generating a second signal corresponding to the pattern thereof, and means responsive to correspondence of the first and second signals for operating the control member only upon substantial identity between the patterns thus compared. In still another aspect thereof, the control system of our invention is characterized by the provision of a control member, and means for operating the control member automatically in response to a pre-selected fingertip pattern, the operating means including means for scanning a fingertip and generating a first series of pulses corresponding to the pattern thereof, means for simultaneously scanning a reference fingerprint and generating a second series of pusles corresponding to the pattern thereof, means controlled by the first and second series of pulses for generating a third series of pulses in correspondence with concurrent first and second pulses, and means operating the control member in response to a predetermined number of third pulses generated within a predetermined time interval, whereby the control member is operated only upon substantial identity between the patterns.
The foregoing and other objects, advantages and characterizing features of our invention will become clearly apparent from the ensuing detailed description of one, illustrative embodiment, and a modification of a portion thereof, taken together With the accompanying drawings illustrating the same wherein like reference numerals denote like parts throughout the various views and wherein:
FG. 1 is a schematic view of a door, showing the location of the finger scanning unit of our invention adjacent thereto;
FIG. 2 is a fragmentary, schematic view, on an enlarged scale, of the door releasing and opening mechanisms;
FlG. 3 is a block diagram of a control system of our invention;
FIG. 4 is a front elevational View of the scanning unit, with the shield removed;
FIG. 5 is a fragmentary, side elevational view thereof;
FIG. 6 is a schematic, top plan view thereof, on a reduced scale;
FIG. 7 is a detailed circuit diagram, corresponding to the block diagram of FiG. 3;
FIG. 8 is a schematic top plan view of a modified scanning unit; and
FIG. 9 is a diagrammatic, sectional view taken about on line 9--9 of FIG. 8.
Referring now in detail to the accompanying drawings, there is shown in FiGS. 1-7 an illustrative embodiment of our invention as applied to the control of a door 1 which is conventionally hung, as by hinges (not shown) at the upper left-hand corner as viewed in FIG. 2, for opening movement in the direction of the airow 2. The door has a jamb 3 with `a projection 4 against which the door closes. This can :be a conventional door having a regular lock and key operated lock release (not sho'wn), but also having a door control mechanism of `our invention.
There is shown, by way of illustration, a latch bolt 5 extending between jamb 3 and door 1 to hold t-he latter against opening movement, and adapted to be retracted into the jamb upon energization .of a coil 6. Bolt 5 `also could be retracted by a key, if desired. Coil 6 can be energized from any appropriate source, not illustrated. In addition to releasing door l, by retracting latch rbolt 5, lwe preferably provide means for opening the door. Such -means can include a plunger 7 which is projected forwardly upon energization of coil 3 to push the door in light' source 1-1.
tip in tray 22.
aannam Y Y are held together by spacing struts 36 which also engage fingertip pattern, and provides means for comparing the pattern 4of a fingertip presented at a test station with theV pattern of a master or reference print, .and vclosing switch 168 only when the patterns are identical. To this end, a scanning unit .10 is conveniently positioned adjacent door 1, as shown in FIG. 1.V The scanning unit, as shown in detail ,in FIGS. 4-6, comprises a housing containing a Mirrors 1|2 and simple lenses 1-3v focus light from source 11 on two plates 14 eachhaving a very 'small aperture, such asa No. 60 hole, therethrough to provide essentially a point o'f lightatV a 4test station, .de-
noted by point 15, and at a reference station, denotedV by point Y16. A slide 17 is guided by a channel 18 for moveyment lengthwise of the slide, and hasY a pair of slotsz and 2'1 therethrough elongated inthe direction of movement of .the,slide. Slot 20 is alined with'point 1-5, and is surrounded on three sidesby va vfinger centering trayy 22 defining therewith a 4linger test station. Slot 2-1 is alined Vwith point 1-6, and with a master print 23 on a transparency positioned-in a pocket 24 carried by slideVV 17 and defining, with slot 2d and point 16, a reference` station. l
Amaster photocell 2.6 is positionedvon a bracket V2.5 in alinement with point 16, to be energized :by light passing through print 23, the pocket 24 being sloted in alinementw ith slot 21 'for this purpose. A test photocell 26Y is positioned within lthe housing approximately 1A Vinch behind slide 17 Vand slot.20, to be energized by light revilected from a Vlinger tip posit-ion over slot 20. The operation `of this scanning unit .is as follorws.
A person desiring admittance places the proper linger |This automatically centers the ringer tip relative to slot 20 and point 15, and .closes switch 33 to ,turn on the unitr(see FIG. 7). Because light from source 111 has been reduced to substantially a point at 15 and' 16, only a veryV small portion of the finger tip is illuminated, and only the corresponding por-tion of the VVrefer- .ence print 2-3 isfilfluminat-ed. The person then pushes -slide 1-7,to the right in FIG. 4, untilV it is stopped by pin 49. This causing the portions of the linger tip andthe master print which are alined w-ith slots 20 vand-21V to be scanned by photocells 26 ,and-26', respectively. The photocells see only asmall point of the respective patterns a-t any one instant, and by scanning in this manner .the variations in light intensity, produced by the Vfinger an end wall'member 37 and the vertical guide 28.
Photocel'ls .26 and V26 are here selected to admit only a point of` light, whereby they see only corresponding parts of the reilected patterns. Upon moving member 27 upwardly, the entire pattern is scanned, as before.
Member 27 is moved by asolenoid 39 which pivots a 'lever'4 about a tulcrum 4,1,y the lever being connected to member 27 for elevating .the same -against the action of a :return spring'42. Solenoid 39 willV be energized upon actuating switch 33, with a timev delay to allow the unit to warm up, if desired. Also, it will .be energized [only once for each actuation 'of .switch 33.
Turning-now to the detailed circuit diagram of FlG. 7,
j which is depicted in block diagram form in FIG. 3, it
will Vbe `seen that identical signal generating circuits are provided for' the master or `reference, print and the test finger. Thus, considering lfirst the master circuit there Vis provided Ythe photocelil-26 connected bet-Ween a load rresistor 5t) and ground, across lthepower supply. Variations in the pattern of light onphotocell26, caused by .the Ypassage of alternating light and dark areas across Vpoint 1.6 as print 23 is scanned, generate current pulses which pass to the amplie'r input through the coupling condensor 51. The tirst amplifier stage-comprising transistor 52, bias resistance. 53, and load Vresistance 54, yampli-fies .these pulses Ywhich then -pass to asecond ampliffier stage through coupling condenser 55. The second Vstage, consisting of transistor 56, bias resistance 57, and
load resistance 58, further 4amplilies the signal pulses, and
inverts lthem n byV changing their polarity.
The amplifier stages are connected to a leveler circuit,
through coupling resistance V59. The leveler is a conven- 'tional Schmitt trigger circuit, having a transistor 60, load Vresistance Y 1l and Vresistance-capacitance coupling network 62, 63. Theoutput of transistor 6i) passes to the amplifier sectionicomprising transistor 64 having a bias resistance 65 and load resistance 66. lA common emitter resistance `67 is provided.
Theresult'is the production of a pulse of maximum amplitude, regardless of the input amplitude, so long as the inputisignal pulse is of sufiicient strengthor amplitude to turn on transistor 60. Variations in the amplitude of the input` pulses, such as will naturally occur, are thereby accommodated, and the level, Iuniform output pulses of maximum amplitude are transmitted to the rst gate tran- Asistor 68 through a coupling resistance 69. L
The -signal generating circuit thus described is` identical. for the test finger, andthe corresponding elements are therefore ,correspondingly numbered, but with primes to. denote the test circuit as. distinguished yfrom the master circuit.. Of course, `inthe test circuit the signal pulses -saregenerated by variations in'the intensity of reflected patterns cause a corresponding variation in the energization of the photocells. With vthe apparatusthus described, corresponding portions of the two'patterns,test and reference, are scannedin synchronism. y
Upon retracting the linger, switch 33 is opened vand spring 47 returns slide 17 against stop 48. A hoodA 46 Y encloses slide 177, except at the finger Ventrance end, to shield the photocells .from extraneous light. A
An alternate scanning ,arrangement is illustrated in FIGS. Sand 9. Here, instead of moving the nger and reference print, relative to the photocells, the photocellsy are mounted on a slide 27,' guided on an upright 2-8, for
vertical movement. The ngerto tbe tested isY presentedv f at an aperture 29 in a member 3), and the 'reference pattern 31 is mounted in a second apertureV 32'. Switch 33 is again positioned to be yactuated upon inserting a stinger vin aperture 29, -forg initiating the scanning procedure. i
Light sources 11l are beamed one onthe reference vprint 31and the other on the finger aperture. Objective flenses 34, carried by a wall member 35,V -focus the reflected pattern onto photocells V276262 Members `30 and 35 light, caused'by the passage of alternating ridges and groovesV past point 15.-'
Thus, the test circuit generates a signal which istransmitted to its `gate vtransistor 68,', and it is a vparticular Vfeature of this inventionthat the gate transistors 68 and ,68 are connected in series'. Accordingly, both gate transistors mustybeenergized or'turned on in order to open the gateand produce an output, pulse. IfV during operation of the nger slide as previously-'described, there is produced .af master pattern signal pulse Without a corresponding signal pulse being produced by the finger patternunder test, there will not be the requisite energiza- `tion of ftransistors -68 Vand .68V andy the gate circuit will not be completed. Therefore, .only when the master pattern and the test pattern'are identical, resulting in the y.generation of concurrent pulses, lwill the two gate transistors be energized at the, same time to permit the passage of an output pulse.
When transistors 68 and 68 are simultaneously energized, a voltage drop occurs across loady resistance 7i),
Agenerating a pulse transmitted to an inverter andlimiter circuit through coupling resistance 71.y The limiter comprises a transistor 72 with a relatively low bias resistance 73 selected so as to prevent the passage of random pulses such as might be produced by stray noise, and the like. Therefore, transistor 72 conducts only when energized by a signal of suiicient amplitude, such as produced upon concurrent operation of the first two signal generating circuits.
Upon energization of transistor 72, the voltage drop across its load resistance 74 produces a pulse identified as a gate reset signal pulse, and this is transmitted to the pulse release circuit through coupling condenser 75.
The pulse release circuit is designed to generate or release a pulse upon energization by a gate reset signal pulse. However, this can occur only when the pulse release circuit has rst been conditioned by a signal pulse derived from one of the pattern signal generating circuits. ln the embodiment shown, the gate energizing pulse from the linger test signal generating circuit also is transmitted, via coupling condenser 76, to one side of the pulse release circuit as a set signal pulse. This sets the circuit to release a pulse when the other side of the release circuit is energized by a reset signal pulse from the gate.
`is turned on, producing a voltage drop across its load resistance S6. This produces a pulse which triggers a pulse Shaper circuit through coupling condenser S7.
The resistance-capacitance network 88, S9 maintains the first set side of the pulse release circuit energized, pending energization of the second side by the reset signal. If the reset signal is not received, the pulse release circuit simply stays in the condition to which it is set by the set signal, and no triggering pulse is released to the pulse Shaper circuit. If only the reset signal is received, without prior conditioning by a finger set signal, no pulse is released to trigger the Shaper circuit. The nip-lop release circuit must rst be conditioned by a signal from one of the pattern responsive signal generating circuits.
f responsive circuits to the gate.
The pulse Shaper circuit is merely a monostable tlipop circuit, identical with the pulse release circuit except that the holding network 88, S9 is replaced by a holding condenser 90 which maintains the transistor 91 conductive or turned on and thereby stretches out the generated pulse. Transistor 91 has a load resistance 80' and a bias resistance 93, and has a resistance-capacitance network 81', 82 coupling it to transistor 92 which has a load resistance 95 and bias resistance 9d.
The pulse shape is thereby enlarged or lengthened, and this pulse is transmitted via coupling condenser 97 to the transistor 98 of a memory circuit. Transistor 9S is provided with a base bias resistance 99 and an emitter bias resistance 100, and has in its collector circuit the memory condenser 101.
Condenser 101 has a most important function, in that Vit comprises the memory device in which the generated in its emitter circuit reaches the predetermined firing point. This voltage level can be reached only when a suicient number of pulses are stored in condenser 101. 1f enough pulses are received, to reach the requisite voltage level, then transistor 102 is turned on.
In addition, the requisite number of pulses must reach the memory condenser 101 within a predetermined time interval, as determined by a variable load resistor or potentiometer 103 which gradually dissipates the energy stored in condenser 101. If the arrival of pulses at condenser 101 is not at a rate exceeding the rate of dissipation of their effect through resistance 103, then control transistor 102 will not be turned on. This can occur only if the patterns being compared are identical, at least to a predetermined high degree, because otherwise the number of concurrent pattern responsive pulses will not be sufiicient to provide the required number of gate pulses.
If transistor 102 is turned on, it provides a short circuit for condenser 101, immediately discharging the same. This causes a voltage drop across resistance 103, producing a negative pulse which is transmitted via condenser 104 and reverse diode rectifier 105 to a pulse-shaping circuit. This pulse shaping circuit is identical with the pulse Shaping circuit previously described except that the output load resistance is replaced by a relay coil 106. Coil 106 is connected across the power supply via current limiting resistance 115. The condenser 107, which is larger than condenser 90, stretches out the pulse suiieiently to pull in relay 106 and thereby move the Switch to a closed position. Transistor 109 has a bias resistance 111, and is coupled via resistance-capacitance circuit 113414 to transistor 110 with its bias resistance 112.
The reverse diode rectifier will pass only the negative pulses, produced upon turning on transistor 102, while preventing passage of the relatively positive pulses as they are being stored in the memory condenser 101.
Accordingly, it is seen that our invention fully accomplishes its intended objects. The iinger under test is directly scanned, without requiring that a separate print be taken, and its pattern is compared With a reference pattern. Only when the patterns are identical, or as nearly identical as required, will the door be opened. The pattern being compared can be the typical, alternating ridge and groove pattern, or it can be the pattern of surface variation on the ridges or grooves, and by proper selection of components a degree of discrimination equaling and exceeding that which is available with key-opened locks can be obtained.
Obviously, the control system of our invention is applicable to actuation in response to skin surface patterns other than inger tip patterns. Also, means other than scanning, such as multiple light sensitive cells, can be used to read the skin surface being tested. For greater security, simultaneous presentation of two or more preselected skin surfaces, belonging to one or more persons, can be required for operation of the device.
While We have disclosed and described in detail only one embodiment of our invention, and one modiication of a portion thereof, that has been done by Way of illustration only without thought of limitation. Variations and modifications will naturally occur to those skilled in the art, and are intended to be included within the scope of the appended claims. Also, we are aware that our invention has utility in lields other than the control of doors.
Having fully disclosed and completely described our invention, together with its mode of operation, what we claim as new is:
1. A door controlling system comprising, in combination with a door control member, means for operating said control member automatically in response to a preselected ingertip pattern including means for Scanning a fingertip and generating a rst signal corresponding to the pattern thereof, means for simultaneously scanning a ref- 27 n erence finger print and generatingY a secondv signal cor-V responding to the pattern thereof, and means'responsive identity between said patterns.
2. A door unlocking systemcomprisin'g, in combina` .Simi-196i y to correspondence of said first andV secondsignals for Y energizing said operating meansonly rupon substantial' tion with a door and a lock for said door-,1a lock releasing Y controllingrelation to said lock releasing circuit, means -for scanning a fingertip and generating a first signal corresponding to the pattern thereof, means for simultane- Y ously scanning a reference finger print and generating a second signal corresponding to the patternl thereof, and means operable in response to correspondence of said first and second signals for actuating said control device only upon substantial identity between said patterns,
. f3 a predetermined number of third pulses before energizing said operating means.
9. A door control system as set forth in claim 8, wherein said last-named means require energization by a predeterminednumber of third pulses within a predetermined time interval before energizing said operating means. v Y Y 10.y A door controlV system comprising, in combination with a door and a contr-ol member for said door, means for operating said contr-ol member autom-aticallyrin response to a pre-selected finger tip pattern, said operating .means including means for scanning a finger tip and gen- Y Verating a'fi'rst series of pulses corresponding to the pattern 3. A door control system comprising, in combination s.
with a door anda control member forsaid door, means for operating said door control member automatically in ,response to a pre-selected finger tip pattern including a .spondence of said first and second Vsignals for energizing; -v
said operating means only upon substantial identity between said patterns. Y Y Y 4. A door control system comprising, in combination with a door and a control member for said door, Ymeans for operating Vsaidcontrol member automatically inref sponse to a pre-selected finger tip pattern, said operating means including means for illuminating -a finger tip presented by a'person desiring to operate said control member, means for illuminating a reference fingerprint, photof electric means for scanning the illuminated fin-ger tip and generating a Vfirst signal corresponding to the pattern thereof, photoelectric means for simultaneously scanningV the illuminated reference print and generating a second .signal corresponding to lthe pattern thereof, and means Y' responsive to correspondence ofY said first and second signals for energizing said .operating Ameans only upon .substantial identity between said patterns.
5. The system -of claim 4,'Wherein said scanning is accomplished by exposing only small corresponding portions of the finger-tip and the reference print to the'associated photoelectric means at any one time, and moving the tip and the print relative to said photoelectric means.
6. The system of Aclaim-4, wherein said scanning is accomplished by exposing only small corresponding Vportions of the finger tip and the reference print tothe associated photoelectric means, and moving said photoelectric means, relative to thetip andthe print.
7. A door control system comprising, in combination With a door and a control member for said'door, means for operating said control member automatically in rep sponse to a pre-selected finger tip pattern,'said operating z thereof, means for simultaneously :scanning a reference fingerprint and generating a second series of pulses corresponding to the pattern thereof, pulse gate means controlled by said first and'second series of pulses and vgenerating a third series of pulsescorresponding to concurrent first and second pulses, pulse release means energized by saidthird series of pulses andk controlled by one of said first and second series of pulses for generating a fourth series of pulses, said pulse release means generating a fourth pulse for each third pulse for which there is a Apulse from said one series thereof, and means responsive to fourth series of pulsesl for energizing said operating means;
11. A door controlling system comprising, in combina- .tion with a door and v,a door control member, means for operating said control member automatically in response to a pre-selected skin surface pattern including means Vvdirectly responsive to la skin surface for generating a first rsignal corresponding to the pattern thereof, means responsive to a reference skin print for generating a second signal corresponding to the pattern. thereof, and means responsive to correspondence of said first and second lsignals for energizing said operating means only upon substantial identity between said patterns.
12. A control system comprising, a control member, and means for operating said. control member auto- Vmatically in response -to a pre-selected'skin surface pattern, said operating means including means for scanning `a skin surface and generating a first series of pulses4 corresponding to the pattern thereof, means for simultaneously scanning a reference skin print and generating a second series of pulses corresponding to the kpattern thereof, means controlled by said first and second series of pulses for generating'a third series of pulses, said lastnamed means generating a pulse only in `response to concurrent first and second pulses, and means responsive to said third series of pulses for energizing said operating means only upon substantial identity between said patterns. Y v
Y 13. A control system as set forth in claim 12, wherein said last-named means require energization by a predetermined number Vof third pulses before energizing said operating means. A
14. A control system as set forth in claim 13, ywherein `said lastnamed means require energizationby a predetermeans including means for Vscanning a `finger tip and generating la first series of pulses corresponding to the pattern thereof, means for simultaneously scanning la reference fingerprint and generating a second series of.
second pulses, and meansV responsive to said third series l substantialridentity between said patterns.
8. A door control system as set forth in claim 7,
'of pulses for energizing said, operating vmeans onlyupon y wherein said last-named means re'cplirey energization by l '15 mined number of third pulses Within a predetermined time interval before energizing said operating means.
15. A control system comprising, a control member,
and means for operating` said control member auto-Y matically in response to presentation of a pre-selected skin surface pattern, said operating means including `means kfor directly reading a skin surface pattern and comparing it to a reference pattern, positioning means `rf-or receiving a pre-selected skin surface portion and positioning itin predetermined relation to said direct reading means, and means. responsive to a predetermined degree of correspondence'between said patterns for energizing said operating means. f f
16. A control system as set forth in claim '15,'together with control means associatedV with said positioning means for actuation upon positioning of said pre-selected Vskin surface portion by said positioning means.
17. A control system comprising, a control member, means for operating said control member automatically in response -to a pre-selected skin surface pattern, said operating means including means for illuminating a skin surface presented by a person desiring to operate said control member, means for scanning the illuminated skin surface and generating a irst signal corresponding to the pattern thereof, means for scanning a reference skin4 surface print and generating a second signal corresponding to the pattern thereof, `and means responsive to correspondence of said rst and second signals for energizing said operating means only upon substantial identity between said patterns.
1S. A door control system comprising, in combination with a door and a control member for said door, means for operating said control member automatically in response to a pre-selected fingertip pattern including la test station adjacent said door for presentation of a finger-tip by a person desiring to control said door, positioning means for centering a pre-selected fingertip presented at said station, means directly responsive to `a ngertip thus l@ presented and centered at said test station for generating a rst signal corresponding to the pattern thereof, means for generating a second signal corresponding to the pattern of a reference ngerprint, and means responsive to correspondence of said iirst and second signals for energizing said operating means only upon substantial identity between said patterns.
References Cited by the Examiner UNiTED STATES PATENTS 511,668 12/93 lVeymouth 16-80 1,941,150 12/33 Meyer 70-160 2,893,726 7/59 Sharpe 268-72 2,936,607 5/60 Nielsen 70-277 3,029,345 4/62 Douglas 70-277 X FOREGN PATENTS 998,272 9/51 France.
ALBERT H. KAMPE, Primary Examiner.