US2603334A - Coin-controlled lock - Google Patents

Description

July 15, 1952 T. F. cURRl-:N 2,603,334

COIN-CONTROLLED LOCK Filed Nov. 13, 1945 3 Sheets-Sheet l T. F. CURREN COIN-CONTROLLED LOCK July 15, 1952 3 Sheeis-SheetI 2 Filed Nov. l5, 1945 DwwsfP/JPPI INVENTOR.

July 15, 1952 T F CURREN 2,603,334 y coIN-CoNTRoLLED Loox Filed Nov. 13, 1945 '3 Sheets-Sheet 5 @fbg-VD i /Illlllllllllllllllllll 7AM/114s] l2/ppm" INVENTOR.

,47- raz-Parr Patented July 15, 1952 2,603,334 COIN-CONTROLLED LOCK Thomas F. Curren, Altadena, Calif., assignor to Pacific Coin Lock Co., Los Angeles, Calif., a corporation of California Application November 13, 1945, Serial No. 627,981

Claims. `(vCl. 194-59) t 1 i o This invention relates generally to coin control locks of the type commonly installed on public pay stations, and relates more particularly to improvements in the coin releasing latch which a coin control lock that Will obviate the existing defects of prior locks and be capable of operating under adverse treatment and abnormal conditions. The lock is of sturdy construction and designed for unfailing operation, thus assuring the user admittance upon the insertion of the proper com.

The invention contemplates particularly a novel coin releasing latch for controlling the operation of the outside operator, and in this connection, a control which is independent of the bolt to the extent that the position of the bolt does not affect the operation of the coin releasing latch.

' Thus the coin releasing means is associated with, but operates independently of the bolt, allowing free operation of the bolt from its extended position to its fully retracted position. Because of its independence from the bolt position, 'the coin releasing means is assured of being conditioned to fully retract the bolt upon insertion of the proper coin, even though the bolt may only be partially projected. ThereforeA the lock cannot become inoperative, and the coin releasing latch is inv condition for reception of a coin after each opening and closing of the door.

Other features and objects of the invention will be better understood from the following detailed description, throughout which reference' is had to the accompanying drawings, in which:

Fig. l is a vertical cross-sectional view taken substantially as indicated by line I-I of Fig. 2;

Fig. 2 is a vertical transverse sectional view taken on line 2-2 of Fig. 1;

2 Fig. 3 is a horizontal transverse sectional view taken on line 3--3 of Fig. 1;

Fig. 4 is a fragmentary vertical sectional View taken on line 4-4 of Fig. 2, illustrating the parts controls the manual bolt retracting operator. 5 in their normal unactuated position with a coin Coin control locks nowv in general use, fail to in position to release the latch upon movement (cope with all conditions` and situations under of the outside operator;

which the locks are required to operate. The Fig. 5 is a view similar to Fig. 4 illustrating the locks o f this type operating in public service are position of the parts after the outside operator subjected to tampering and abnormal usage and 10 has been actuated and the bolt fully retracted;

require a lock that will not only stand abuse, but Fig. 6 is a view similar to Fig. 5 illustrating the the various devices thatmay be attempted to position of the parts after release of the outside render the control inoperative or permit free use manual operator;

of the station. Prior coin control locks have Fig. 7 is afragxnentary vertical transverse secfailed to assure the expectant user admittance 15 tion taken on line I-I of Fig. 1;

after he has trustingly inserted a coin. For ex- Fig. 8 is a fragmentary vertical sectional View ample, many ordinary coin control locks depend taken on line 8 8 of Fig. 7

upon the return of the keeper-engaging bolt to Fig. 9 is a perspective View of the bolt embodied its normal position for reception of a coin. If in the invention;

for any reason the bolt fails to return to normal 20 Fig. 10 is a perspective View of one of the position, as when a previous user has tampered latches embodied in the invention;

with the keeper, e. g. by lling it with paper, such Fig. 11 is a perspective view of the control plate locks are found either to be made inoperative, or associated with the latch means embodied in the uncontrollable as intended. invention; and A general feature of the invention is to provide 25 Fig. 12 is a perspective view of the coin releasing latch plate or connecting member between the outside manual operator and the bolt.

The coin control lock illustrated in the drawings includes generally a lock body I0 attached to the door D and carrying a sliding bolt II. A keeper I2 is located adjacent the door opening and adapted to receive the bolt for locking the door. Manual operating means I3, termed the outside operator, is provided at the outside of the door for retracting the bolt vII to open the door. A vcoin releasing latch assembly I 4 is provided between the outside operator I3 and the bolt II for holding the outside operator inoperative until the proper coin has been inserted. The latch assembly I4 includes a control latch I4I associated with and operable independently of the bolt, and a secondary latch I5. During the later described operating sequence, the latch means I4I is momentarily held inoperative by the secondary latch I5 which is associated Withand conditioned by operation of the latch I4I. The secondary latch I5 allows the outside operator I3 to be repeatedly operated during opening of the door, rendering the coin releasing latch I4I inoperative, until the bolt has been retracted as by closing of the door. An inside manual operator I6 located at the inside of the door, retracts the bolt independently of the outside operator so that it is at all times conditioned for operation.

The body ID of the lock includes `a plate-like member attached to the outside of thel door Dby suitable screws I'I and forms a mounting for the various parts of the lock. Typically, the bolt IjI is substantially square in transverse cross-section and is slidably carried on the outer face of the body between projections or guides I8. The wedge shaped outer end or keeper-engaging portion I9 normally projects from the side of the lock. A retaining plate 29 secured to the guides I8 by screws 2I retains the bolt in the guideway. The bolt is yieldingly urged in its extended or projected position by spring 22 connected to a projection or arm 23 on the rear end of the bolt and a projection 24 on the retaining plate 20.

The latch 14| includes a control plate 25 slidable on the outer faces of the guides I8 and at the inside of a retaining plate 2B, see Figs. 3, 4 and 12. The plate 26 is secured at its bifurcated forward end 26I to the outer face of the guides I8 by screws 26a and has a lateral offset portion 26h spaced from the plate 25 to allow reception of a coin C, as illustrated in Figs. 3 and 4- of the drawings. The rear end of the plate 26 is secured to and in spaced relation with the outer faces of the guides I8 by screws 25e. The retaining plate 26 is provided with an elongated slot 26d adjacent the rear end of the plate, to pass arm 23 on the bolt I I. A second slot 26e in the plate 26, located under the slot 25d adjacent the lower edge of the plate, receives a spring safety catch 'l5 as will be later described.

As will appear, under the iniiuence of the outside operator I3, the plate 25 is capable of limited reciprocations relative to the bolt, followed by engagement with the bolt to retract it from the keeper. Plate 25 has a lateral projection or finger 28 engageable with a shoulder 23 formed on the bolt I I at the end of a recess 36 in the outer face of the bolt II. A notch 3| in the upper edge of the plate 25 is adapted to receive the active end of a pivoted pawl 32 for preventing reciprocation of the plate previous to the insertion of a coin. The pawl 32 is pivotally carried on one of the screws 26C in the upper portion of the space S, and is urged downwardly into engagement with the plate 25 by a spring 34. Downwardly projecting spaced lugs 35 are provided at the under side of the plate 25 to receive a pin 36 carried on an arm 3T fixed to stern 38 of the outside operation I3. Construction and movement of the operator I3 to cause reciprocation of the control plate 25, will be later more fully described.

Releasable coin retaining means 39, see Fig. 4, z

plate 25. The coin retaining means 39 includes a pin 40 projecting from the outer face of the plate 25 adjacent its lower edge. A spring-urged latch plate 4I, see Figs. 3 and 11, located behind the control plate 25 has projections 42 and 43 extending through elongated openings 44 and 45 in the control plate. The latch plate has limited relative movement with respect to the plate 25 and has movement therewith. The coin C inserted in the usual coin slot 'It drops through the chute 'II into the space S between the control plate 25 and the retaining plate 26, coming to rest between the pin 46 on the control plate 25 and the rearward projection 42 on the latch plate 4I. The latter is positioned behind the control plate 25 and is received within the bolt recess 39. Rotation of the outer operator I3 causes reciprocation of the control plate 25 in a rearward direction, bringing finger 23 on the plate 25 into engagement with the bolt shoulder 29. The coin retained between pin 40 and projection 42 engages pawl 32, causing pivoting of the pawl out of the notch 3I in the control plate 25, thus allowing retraction of the bolt I I.

The secondary latch means I5 includes a pawl 46 pivotally carried in a slot 4l in the upper guideway IB. The outer end of the pawl 46 is urged downwardly by a spring 48| to normally rest on the upper face of the latch control plate 4I and overlie a portion of bolt II, as clearly illustrated in Figs. 7 and 8. Plate 4I being of substantially the same height as the bolt I I, is confined vertically between guides I8, and laterally between the inner face of the control plate 25 and the outer face of the bolt recess 30.

A spring 48 attached to the forward projection 43 on plate 4I and to a forwardly projecting arm 49 on the control plate 25, yieldingly urges the latch plate 4I forwardly. The outer end of the projection 42, the spring 48, and the arm 49 are received in the bifurcated end of the plate 26 for relative movement. The upper ends of the bolt I I and the latch plate 4I are in substantially the same plane. The bolt II is provided with a camming notch 50 in its upper face and the latch plate 4I is provided with a forwardly facing shouldered notch 5I in its upward face. Notches 50 and 5I are adapted to receive the active end of the pawl 46 upon actuation of the control plate 25. The notch 50 and the notch 5I are normally in staggered relation, as clearly illustrated in Figs. 4 and 8.

When the coin releasing latch means I4I is in its normal position, movement of the control plate 25 by the outside operator I3 causes simultaneous movement of the latch plate 4I through the association of projection 43 with the receiving slot 45. The nger 28 on the control plate 25 is normally in spaced relation to the bolt shoulder 29, thus allowing slack motion between the control plate 25 and the bolt II. This slack motion allows the staggered notches 5U and 5I in the bolt I I and the latch plate 4I, respectively, to come into alignment simultaneously with the engagement of the nger 28 with shoulder 29. At this time the coin has cammed the pawl 32 out of the notch 3| in the plate 25. Further movement of the control plate 25 retracts the bolt II.

Upon release of the outside operator I3, a spring 52 connected with the arm 31 and a projection 53 on the lock body, yieldingly urges the arm 31 and control plate 25 forwardly. The engagement of the finger 28 with the shoulder 29, as described above, remains, under normal conditions, until the bolt II reaches its fully extended position and the notches 50 and 5I remain in alignment. Thereafter the control plate 25 starts to move relative to the bolt II and the pawl 46 is received in the notches 50 and 5I. Relative movement between the plate 25 and the bolt II brings the shouldered notch 5I into engagement with the pawl, 46, stopping further movement of latch plate 4I. The control plate 25 continues to move relative to the bolt II and the latch plate 4I until the projection 42 on the plate 4I engages the rear end wall of the slot 44. The relative movement between the latch plate 4I and the control plate 25 opens up the space between the pin 40 on the plate 25 and the projection 42 on the plate 4I, thus releasing the coin C. The coin drops into the lower portion of the housing H, encasing the lock proper. The pawl 46 cooperating with the notch 5I in the latch plate 4I, and the projection 42 on the outer face of the latch plate 4I cooperating with the rearward end wall of the opening 44, prevent .return of the control plate 25 to its normal coin bolt Il.

projecting portion I3 of the bolt II engages the keeper I2 causing relative retraction-of the bolt with respect to the plate 25 and its latch control plate 4I. This retraction brings the forward end of the camming notch 5l) into engagement with the under side of the pawl 46, camming the pawl from the notch 5I in the latch plate 4I, and the spring 52 operating through the arm 31, pin 36 and projections 35, returns the plate 25 and its latch control plate 4I to their normal position. This reconditions the coin releasing means I4 for reception of a second coin.

Manual operating means or operator I3 is located at the outside of the door D and its stem 38 is rotatable on the lock body I6 below the The stem 38 is rotatably carried in opening 80 in the body I0 and a bearing bracket 8| secured to the body by screws 82. The arm 31 of the stem 38 is positioned in the space between the inner side of the bracket and the body I0.

Manual operating means I6 located at the inside of the door includes generally an operator 60 rotatably carried in a bearing boss 6I at the inside of the lock body I 0. The inner end of the operator 60 carries a fixed double cam 62 operable to cause retraction of the bolt I I by rotation of the operator in either direction, see Fig. 8.

The operative connection between the cam 62 and the bolt II includes pivoted lever 63 carried on the lock body and pivoted on the stem 38 of the outside operator I3. The lever 63 and the cam 62 are received in a recess 65 in the back side of the bolt II, see Fig. 3. The end wall 66 of the recess 65 is engageable by the rear edge of the lever 63 to transmit movement of the lever to the bolt. A second pivoted lever 61, acting as a shoe between the cam and the lever 63,-is pivotally carried by a pin 68 secured to the body I6.

A spring 69 returns the operating means |6 to its normal position.

Rotation of the operator I6 causes rotation of the cam 62 and lever 63 through the shoe 61, and bringing of the lever into engagement with the shoulder 66 to retract the bolt II. It is apparent that the inside operator I6 is capable of actuation at all times to retract the bolt and regardless of the condition of the remaining parts of the latch assembly.

Assuming the parts are in their positions illustrated in Figs. l, 2, 3, 4, 7 and 8, and the proper coin has been inserted, the lock is in condition for retraction of the bolt. Rotation of the outside operator I3 causes reciprocation or inward Y gagement of the coin with the pawl 32 cams the pawl out of the notch 3| in the control plate, allowing further inward travel of the plate 25. Initial inward travel of the plate relative to the bolt brings notches 50 and 5I into alignment at -the time the finger 28 engages shoulder 29 on the bolt I I. After finger 28 engages shoulder`23,

further inward movement of they plate 25 retracts the bolt II and moves the notches 56 Vand-5I 'to positions just beyond the end of the pawl 46 where the pawl is released, see Fig. 5.

Upon release of the outside operator I3*v after opening of the door, the spring 52 connected with the arm 3l urges the plate 25 forward or outward toward its normal position. If for any reason the bolt does not return, the pawl 46 will be held released by the bolt and the plate 25 will move relative to the bolt and thus cause the notches 5I to move out of alignment with the notch in the bolt, preventing engagement of the secondary latch means I5. The secondary latch means as described above, when in operation causes release of the coin, but due to the failure of the bolt to return, the notch 5I) in the bolt is held out of register with the pawl 46, thus preventing Vengagement of the pawl with the notch 5I. The coin retained in the control latch I4 allows a repeated retraction of the bolt to assure entrance into the pay station.

Upon opening of the door after one or more operations of the outside operator, the operator is released allowing a full unhampered extension of the bolt. Upon the latch plate reaching a position where its linger 28 disengages shoulder 29, the notches 50 and 5I are in alignment and engageable by the pawl 46, thus preventing further outward movement of the plate 4I and permitting relative movement of the plate 25. This relative movement between the plate 4I and plate 25 results in opening of the space between the pin' 46 and the projection 42 allowing release of the coin. The plate 4I holds the control plate 25 from returning to its fully outward or `Anormal position, by projection 42 engaging thewallof the opening 44 in the plate 25, until the doorhas been closed. Closing of the door causes theIend I9 of the bolt II to engage the keeper I2. Engagement of the bolt with the keeper I2 produces full retraction of the bolt. This retraction of lthe bolt brings the forward end of the notch SI1-into camming engagement with the under side of the pawl 46 disengaging it from the notch 5I', allowing the return of the plate 25 and its latch plate 4 I to their normal positions.

I claim:

l. A coin controlled lock including mechanismy ed but preventing complete bolt retracting movement of said operating means and displaceable to a released position, means conditioned by reception of a coin to transmit movement between said mechanism and the latch element for -releasing the element in response to bolt retracting movement of the mechanism, and a holding'part acting independently of the coin afterl release ofthe latch element to prevent relatching thererof to thereby permit repeated retractionI of the bolt by said operating means.

V2. A coin controlled lock including mechanism `comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanism being movable in bolt retracti'n'g direction, a latch element normally allowing llimited but preventing complete bolt retracting movement of said operating means and displaceable to released position, means conditioned/by reception of a coin to transmit movement between said mechanism andthe latch elementifor releasingthe elementin response to bolt retracting movement of the mechanism, a holding part acting independently of the coin after release vof the latch element to prevent relatching thereof to thereby permit repeated retraction of the bolt by said operating means, and means operable in response to retraction of the bolt independently of said operating means to release the holding part and permit relatching of the latch element.

3. A coin controlled lock including mechanism comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanism beingr movable in bolt retracting direction, a latch element normally allowing limited but preventing complete bolt retracting movement of said operatinfI means and displaceable to released position, means for receiving and supporting a coin in a position to transmit movement between said mechanism and the latch element to release the element in response to bolt retracting movement of the mechanism, and a holding part acting independently of the coin after release of the latch element to prevent relatching thereof to thereby permit repeated retraction of the bolt by said operating means.

4. A coin controlled lock including mechanism comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanism being movable in bolt retracting direction, a latch element normally allowing limited but preventing complete bolt retracting movement of said operating means and displaceable `to released position, means for receiving and supporting a coin in a position to transmit movement between said mechanism and the latch element to release the element in response to bolt retracting movement of the mechanism, a holding part acting independently of the coin after release of the latch element to prevent relatching thereof to thereby permit repeated retraction of the bolt by said operating means, and means Yoperable in response to retraction of the bolt independently of said operating means to vrelease the holding part and permit relatching of the latch element.

5. A coin controlled lock comprising a, bolt movable between a keeper engaging position and a retracted position, movable operating means for displacing the bolt to said retracted position,

areleasable latch element normally allowing limr wited but preventing complete bolt retracting movement of said operating means and displaceable to a released position, means for receiving and supporting a coin in a position to transmit movement between said operating means and said latch element to release the element in response -to movement of the operating means in a bolt retracting direction, a holding part acting independently of the coin after release of the latch `mechanismbeing movable to retract the bolt, a

latch element normally allowing limited but preventing complete bolt retracting movement of said operating means and displaceable to a released position, means for receiving and supporting .-a coin in a position to transmit movement .between said mechanism and said latch element toreleasethe element .in response gto boltretracting movement of the mechanism, and a. holding part acting vto prevent complete return of said Y ing of said latch element and permit repeated retraction of the bolt by said operating means.

'7. A coin controlled lock comprising a bolt movable between a normal keeper engaging position and a retracted position, operating means movable between a normal condition and an actuated condition to retract said bolt, a latch element normally allowing limited but preventing complete bolt retracting movementrof said operating means from said normal condition and displaceable to -a released position, means for receiving and supporting a coin in a position to transmit movement between said operating means and said latch element to release the element in response to movement of the operating means in afbolt Yretracting direction, a holding part acting to prevent complete return of -said operating means to normal after movement in a bolt retracting direction `beyond said limited movement thereof to thereby prevent relatchlng of said latch element and permit repeated retraction of the bolt by said operating means, and means operable in response to retraction of the bolt independently of said operating means to release the holding part and permit relatching of the latch element.

` 8. A coin controlled lock including mechanism comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanism being movable in bolt retracting direction, a latch element normally allowing limited bue preventing complete bolt retracting movement of said operating means and displaceable to released position, means conditioned by reception of a coin to transmit movement between said mechanism and the latch element for releasing the element in response to bolt retracting movement of the mechanism, a holding part acting independently of the coin after release of the latch element to prevent relatching thereof to thereby permit repeated retraction of he bolt'by said operating means, and means carried by the bolt and operable in response to retraction of the bolt independently of said operating means to release the holding part and permit relatching of the latch element.

9. A coin controlled lock including mechanism comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanismV being movable in bolt retracting direction, a latch element normally allowing limited butpreventing complete bolt retracting movement of said operating means and displaceable to released position, means movable with said mechanism and conditioned by reception of a coin to transmit movement between said mechanism and the latch element for releasing the element in response to bolt retracting movement of the, mechanism, a holding part acting independently of the coin after release of the latch element to prevent relatching thereof to thereby permit repeated retraction of the bolt by said operating means, and means operable in response to retraction of the bolt independently of said operating means to release the holding part and permit relatching of the latch element.

10. A coin controlled lock comprising a bolt movable between a normal keeper engaging position and a retracted position, a movable operator for retracting the bolt, a movable unit for transmitting retracting movement from said operator to the bolt, a latch element normally allowing limited but preventing complete bolt retractng movement of said unit and displaceable to a released position, said unit including means for receiving and supporting a coin in position to transmit movement from the unit to said latch element to thereby release the latch element in response to movement of the unit in a bolt retracting direction, and a holding part acting independently of the coin to prevent complete return of said unit to normal after movement in a bolt retracting direction to thereby prevent relatching of said latch element and permit repeated retraction of the bolt by said operating means.

11. A coin controlled lock comprising a bolt movable between a normal keeper engaging position and a retracted position, a movable operator for retracting the bolt, a movable unit for transmitting retracting movement from said operator to the bolt, a latch element normally a1- lowing limited but preventing complete bolt retracting movement of said unit and displaceable to a released position, said unit including means for receiving and supporting a coin in position to transmit movement from the unit to said latch element to thereby release the latch element in response to movement of the unit in a bolt retracting direction, a holding part acting independently of the coin to prevent complete return of said unit to normal after movement in a bolt retracting direction to thereby prevent relatching of said latch element and permit repeated retraction of the bolt by said operating means, and means operable in response to retraction of the bolt independently of said movable unit and operator to release the holding part and permit relatching of the latch element.

l2. A coin controlled lock including mechanism comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanism being movable in bolt retracting direction, a latch element normally allowing limited but preventing complete bolt retracting movement of said operating means and displaceable to released position, means conditioned by reception of a coin to transmit movement between said mechanism and the latch element for releasing the element in response to bolt retracting movement of the mechanism, a holding part acting independently of the coin after release of the latch element to prevent relatching thereof to thereby permit repeated retraction of the bolt by said operating means, and means fory releasing said coin from said coin conditioned means upon the first return of said mechanism from retracted condition.

13. A coin controlled lock including mechanism comprising a retractable keeper engaging bolt and movable operating means therefor, said mechanism being movable to retract the bolt, a latch element normally allowing limited but preventing complete bolt retracting movement of said operating means and displaceable to a released position, means for receiving and supporting a coin in a position to transmit movement between said mechanism and said latch element to release the element in response to movement of the mechanism in a bolt retracting direction, a holding part acting to prevent complete return of said mechanism to normal after movement in a bolt retracting direction to thereby prevent relatching of said latch element and permit re- 10 peated retraction of the bolt by said operating means, and means for releasing said coin from said coin supporting means upon the rst return of said bolt from retracted condition.

14.. A coin controlled lock comprising a bolt movable between a normal keeper engaging position and a retracted position, a movable operator for retracting the bolt, a movable unit for transmitting retracting movement from said operator to the bolt, a latch element normally allowing limited but preventing complete bolt retracting movement of said unit and displaceable to a released position, said unit including two sections adapted to support a coin in position to transmit movement from the unit to said latch element and to thereby release the element in response to movement of the unit in a bolt retracting direction, said two sections being relatively movable to release the coin, a holding Dart acting to engage said unit and prevent its complete return to normal after movement in a bolt retracting direction to thereby prevent relatching of said latch element and permit repeated retraction of the bolt by said operator and unit, means for eiecting coin releasing relative movement between said sections of the unit upon restraint of the returning movement of said unit by said holding part, and means operable in response to retraction of the bolt independently of said movable unit and operator to release the holding part and permit relatching of the latch element.

15. A coin controlled lock comprising a bolt movable between a normal keeper engaging position and a retracted position, a movable operator for retracting the bolt, a movable unit for transmitting retracting movement from said 0perator to the bolt, a latch element normally allowing limited but preventing complete bolt retracting movement of said unit and displaceable to a released position, said unit including two sections interconnected for retracting movement together and for limited relative movement, means carried by said sections and adapted in a lrst condition thereof to support a coin in position to transmit movement from the unit to said latch element to thereby release the element in response to movement of the unit in a bolt retracting direction, said unit being adapted to release the coin upon relative movement of said sections to a second relative condition, a rst spring urging the sections to said first relative condition, a holding part engageable with one section of said unit to prevent complete return of the unit to normal after movement in a bolt retracting direction to thereby prevent relatching of said latch element and permit repeated retraction of the bolt by said operator and unit, a second spring acting to eiect coin releasing relative movement between said sections upon restraint of the returning movement of said unit by said holding part, and means operable in response to retraction of the bolt independently of said movable unit and operator to release the holding part and permit relatching of the latch element.

THOMAS F. CURREN.

REFERENCES CITED UNITED STATES PATENTS Name Date Neckerman Dec. 16, 1924 Number

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