US2902279A - Easel card feeding and glue applying machine - Google Patents

Description

Sept. 1, 1959 F. SPIATTO EASEL CARD FEEDING AND GLUE APPLYING MACHINE Filed April 30, 1957 3 Sheets-Sheet 1 'INVENTOR. FRANK SP/ATTO BY M wfl Attorney Sept. 1, 1959 'F. SPIATTO 2,902,279

EASEL CARD FEEDING AND GLUE APPLYING MACHINE I Filed April 30, 1957 3 Sheets-Sheet 2 INVENTOR. FRAN K 5 PIATTO I-BY 77M gir hfalo Atto'r n2 Sept. 1, 1959 I F. sPlATT EASEL CARD FEEDING AND GLUE APPLYING MACHINE Filed April 30, 1957 3 Sheets-Sheet 3 INVENTOR. FRANK SPIATTO- "94 9 BY Attorney United States Patent EASEL CARD FEEDING AND GLUE APPLYING MACHINE Frank Spiatto, Rego Park, N.Y. Application April -30, 1951, Serial No. 655,994

12 Claims. (21. 2711-44 This invention concerns an improved and practical ca-rd feeding and glue applying machine. The machine finds special use with respect to easels of the cardtype, com- 1. 3 used as leg supports for various advertising displays, such as cardboard signs and the like. The general function of the machine is to continuously pick easel cards from a stack, apply glue to) each along a marginal rocating picker mechanism, which functions in ahighly efiicicnt manner to. pick the easel cards one by one from a stack and carry them into gripping rollers which then serve tocanry them out of the machine.

The. picker mechanism is of a pin type- It operates in an advantageous manner whereby the cards are picked and transmitted to the rollers without being scratched or scored by the pin elements.

A further feature of the invention is certain mechanism which functions automatically to. release the pin elements of the picker mechanism from the picked card shortly after the gripping rollers have gripped the latter.

Another feature of the invention is certain; safety mechanism which. automatically operates. to release the picker mechanism from an easel card; in the event other mechanism for that purpose fails to do. so..

A still. further feature of the invention is an arrangementof" mechanism whereby glueis automatica ly applied to the underside, of each. card as; it is; carriedout or the machine.

A'further object: of this invention; is, therefore, to providea practical and effici ntly op r ing continuous-fee and glue applying-machine for easel cards. 7

Another: objec of; his; invent on to p i n improved continuous.- feed mechanism of, a reciprocating pin type; for sheet articles, such as easel, cards;

The inyentionfurt-her lies in the particular structure of; its component parts and also in their-particular arr-angem'ent and cooperative association with each other to effect the results intended herein.

The foregoingand. other objects and. advantages, of this invention will appear more fully hereinafter from, a consideration. of the detailed, description. which follows, taken together with the accompanying drawings, wherein an. embodiment of the invention is illustrated. It is to be expressly understood, however, that the drawings are for purposes of illustration and description and are not to.- be construed as v defining, the. limits. of the invention.

In the drawings:

Fig, l is, a longitudinal section through an easel card and glue applying machine embodying. the invention;

Fig, 2 is; a longitudinal section on the line 2-2 of Fig. 3;

Fig. 3. is, a cross section on. the line 33 of Fig. 1.; and.

Fig. 4 is a detail of the glue applying mechanism.

. Fig. shows the position. of the picker. mechan m. as engaged with an easel card at the start of a card pick- ICE ing operation; and Fig. 1 shows the picker mechanism in a position just after it had been released from the picked. easel card.

For a more detailed description of the invention reference is now directed to the several drawings wherein the machine illustrated includes an elongated table 1 suitably supported on a framework, not shown, and adapted to support on its surface a stack of easel cards 2. The cards are formed of conventional paperboard or cardboard material. The cards are arranged on the table so that a straight edge 3 of each card abuts against a guide fence 4 that is fixed to the table, and so that the forward ends of the cards abut against a wall 5. fixed at right angles to the fence. A slot 6 is provided above the table below a knife edge 7 of wall 5. Through this slot the bottom card 8 of the stack is adapted to be fed by. picker mechanism 9-between a pair of gripping: rollers 11, 1,2 and over a glue applying wheel 13. Roller 1 1 is carried for rotation by a motor driven cross shaft 14;; while roller 12 is carried for rotation by a cross shaft 1'5 drivingly connected to shaft 14 in suitable manner, not shown. Shafts 14 and 15 are suitably supported. in the framework, not shown, of the machine. The rollers have knurled peripheral surfaces 16, 17 which are adapted to frictionally grip a card passed between them and to carry it out of the machine. The glue applying wheel 1-3 is of the same diameter as the driven roller 11 and is carried in? spaced relation thereto by the same shaft (Fig. 4). The peripheral surface of the glue wheel frictional-ly eng ges the peripheral surface of a gluepickup rotor 18.v which is carried by a shaft 19 that is journalled in thesid'e walls 20 of a glue tank 21. Rotation. of: the drive shaft 14 is transmitted. in order to the rotary elements, 13v and 18, so that glue that ispicked up by the rotor is conveyed ontothe glue. wheel 1-3;. The latter applies the glue to the underside of an easel card along the marginaledge thereof as the card is carried out of themachine by the. g PPingrollers.

The; picker mechanism 9 includesv a parallel pair of longitudinally extending tracks 22 disposed in. the same horizontal plane. The tracks are anchored at their left ends 23 in, a pair of laterally spaced legs 24, one being shown, of a crosssupport 25- affixed to the underside of the table. The opposite ends 26 of the tracks are similarly retained. in the legs 27 of a similar cross support '28. Slidable. back and forth on the tracks is a card picker pin carriage or block 29. The latter is formed with a pair of through holes the inner surfaces of which bear upon the tracks. Hub formations extending from, the right. end. of the block about the holes, as at 31 in- Fig. 2, provide a. greater bearing surface of the block upon. the tracks, whereby wobble and play in the movement. of the block is. avoided. Formed centrally of the lower right end of the block is apair of ears 32 (Fig. 3) between which is pivoted one end of a reciprocating drive link 33. Theopposite end of this link has a hub formation. 34 which pivots on an eccentric pin 35 projecting from a drive. disc 36. The latter is carried. by a power driven shaft 37:, the motor of which is not shown. Rotation of the drive shaft 37 reciprocates the carriage; block 29 over the tracks.

The carriage block carries a card, picker assembly 38. The latter includes a supporting member 39- having a base plate portion 41 disposed above the carriage block. and extending. transversely over the block in parallel relation thereto, as in Fig. 3. Member 39 is mounted fast atop a pair of parallel elevator rods 42 which are. vertically slidable incomplementary holes extending through. the block. The lower ends 43 of the rods project from the underside of the block and are secured fast to a broad crossbar 44'. A coilspring 45 surrounding each rod and compressed between the underside of the block and: the

cross bar constantly urges the supporting member 39 downward to rest upon the top of the carriage block, as appears in Fig. 1.

The supporting member 39 is U shaped, having an upright flange 46 along its left end and an opposed flange 47 along the right end. Supported fast at their ends in these opposed flanges is a pair of parallel spaced horizontal rails or rods 48. Slidably mounted on the rails 48 is a pin block 49. Fastened to the top of block 49, as by a screw 51 in each, is a plurality of parallel strips 52 disposed in spaced lateral relation to each other, as appears in Fig. 3. Fitted fast in each strip is a pair of pins 53 which extend upwardly in line with a longitudinal slot 54 formed in the table. There is a separate slot 54 adapted to freely receive the pins of each strip 52 in a manner as will be hereinafter described.

The pin assembly 38 has a retracted position as in Fig. 1 wherein the supporting base member 39 rests upon the carriage block 29. In this retracted position the points of the pins 53 are below the table surface. The pin assembly has an elevated position, as in Fig. 2, wherein the points of the pins project through the slots 54 and above the table surface for a distance not greater than the thickness of an easel card 2.

In Fig. 1 the carriage block is shown in a position short of the end of the first half of its cycle and just after the pin assembly has been retracted. At the end of the first half of the carriage cycle the pin block 49 has a position at the right end of the rails 48 and abuts, as in Fig. 2, the right flange 47.

Means is provided for elevating the pin assembly 38 so as to engage the pins 53 in the bottom easel card of the stack at the start of a card picking operation; and other means is provided for subsequently retracting the pin assembly so as to release the pins from this bottom card shortly after the forward end of the card has been gripped by the rollers l1, 12.

Below the table and at the right is a lift assembly 55 which is cooperable with the cross bar 44 to elevate the pin assembly. It includes a support having a fixed base 56. An upright portion of the base is formed with a boss 57 in which is fitted a stub shaft 58 on which pivots the hub portion 59 of a bellcrank 61. A forwardly extending arm 62 of the bellcrank carries at its end a pin 63 on which is retained a roller 64. This roller is adapted to cooperate with the central underside area of the cross bar 44 of the carriage so as to elevate the pin assembly 38. The other arms 65 of the bellcrank has a normal upright position (Fig. l) and carries at its free end a cylinder 66 through which a screw 67 is threadable. The latter is elongated and normally projects through both ends of the cylinder. A spring 68 anchored at one end to a fixed support 69 and at the other to an end of the pin 63 tensions the bellcrank in a counterclockwise direction, as in Fig. 1. It is limited in this direction by a suitably supported stop pin 71, so that the bellcrank has a normal position wherein the arm 65 is substantially vertical. The arrangement is such that, as the carriage block 29 is drawn by the drive link 33 'to the right and short of its starting position, a member 72 depending centrally from the right end of the carriage block strikes a rounded end 73 of the screw 67 at just about the time that the cross bar 44 begins to override the roller 64. As the carriage moves a little further to its returned or starting position, the bellcrank is further pivoted clockwise (Fig. 2), whereupon the roller 64 is caused to press upwardly against the underside of the cross bar 44. This raises the pin assembly 38 against the load of the springs 45 sufliciently to enable the pins 53 to penetrate the bottom easel card 8.

Releasable latch means is provided to automatically lock the pin assembly in its elevated position. This includes a latch lever 74 pivoted at its central area 75 in a slot 76 formed in an arm 77 extending leftward from the lower central area of the carriage block. An ear 78 extending leftward from the lever 74, as seen in Fig. 2,

overlies a spring loaded head 79 of a pin 81. The latter is vertically slidable in the arm 77. A coil spring 82 urges the pin upward. The latte-r is curbed in this upward direction by a stop projection 83 adapted to limit against the underside of the arm 77. The spring loaded head 79 urges the latch lever in a clockwise direction. The latch lever has a disengaged or normal position, as in Fig. 1, wherein the pin assembly 38 is in its retracted position. In this disengaged position a rearwardly extending ear or dog 84 at the upper end of the lever presses against the outer left face of the supporting member 39 of the pin assembly. When the pin assembly 38 is raised in the manner earlier described, it is caused by a proper adjustment of the screw 67 to be elevated a distance sufficiently to permit the latch dog under the load of the spring 82 to move below the pin assembly 38 and above the carriage block, whereby the pin assembly is retained in its elevated position. In the locked elevated position of the pin assembly the pins 53 extend through the table slots 54 and penetrate but do not project through the upper surface of the bottom easel card 8, as in Fig. 2.

Means is provided to dislodge the latch dog 84 at a proper time so as to permit the pin assembly to be restored to retracted position by the springs 45. To this end, there is fixed to the center of the left face of the pin block 49, as seen in Fig. 2, a release member 85 which has at its lower end a lug 86 extending to the left. This lug is arranged to ride in part in a slot 87 that opens out centrally of the left end of the supporting member 39, and the lug also rides in part in a lower slot 88 extending centrally from left to right in the carriage block. The latch dog 84 is wider than the slots 87 and 88, and in the latched position the dog 84 overlies the lower slot 88, as appears in Fig. 2. The lug 86 of the release member is extended to the left so that upon a movement of the pin block 49 over the rails 48 from right to left, the lug will abut the latch dog and progressively dislodge it from between the member 38 and the carriage block. Upon release of the latch dog, the pin assembly 38 will be retracted by the springs 45. This left or forward movement of the pin block 49 over the rails 48 occurs during the first half of the carriage cycle after the easel card engaged by the pins 53 has been conveyed to the gripping rollers 11, 12.

As earlier explained, at the start of a card picking operation the pin assembly is held by the latch dog 84 in elevated position and the pins 53 are engaged in the bottom card 8. Now, as the drive disc 36 rotates on the first half of its cycle, the carriage block 29 is moved to the left on its tracks and the engaged card is carried over the surface of the table 1 and through the knife slot 7 to the gripping rollers 11, 12. The latter rotate under the power of a motor, not shown, at a peripheral speed faster than the carriage block moves. Accordingly, the rollers act through the engaged card to pull the pin block 49 from the right to the left on the rails 48 at a rate of speed faster than the carriage moves. Whereupon, the release lug 86 dislodges the latch dog 84. As soon as the latch dog is dislodged the springs 45 act to retract the pin assembly to the position shown in Fig. 1. In this action the pins 53 are withdrawn from the picked card. The gripping rollers continue to act on the card and pull it from the machine and over the glue applying wheel 13.

Subsequent to the above action, the carriage block moves further along its tracks a short distance to complete the first half of its cycle. During this latter movement the pin block 49 is reset or returned to its position at the right end of the rails 48. To this end a pair of parallel and longitudinally extending reset pins 89 is provided. These extend to the right and are fixed at their left ends in the cross support 25. The extent to which the pins project to the right is controlled by threading the pins further in or out of the support 25 as needed. A lock nut 91 serves to set the position of the pins. Now, as the carriage block moves on to complete its forward stroke or first half of its cycle, the openings 92 formedin the left flange 46 of the pin assembly supporting member 39 pass over the reset pins. Whereupon the latter abut the pin block 49 and progressively move it to the right against the right flange 47 as the carriage block completes its movement to the left.

A second, or safety release means is provided to dislodge the latch dog 84 if for some reason the release lug 86 is disabled from doing so. To this end, there is provided a fixed cam block 93 which cooperates with a roller 94 carried at the end of a depending portion 95 of the latch lever. If the latch lever 74 is not pivoted counterclockwise under the action of the release lug 86, the roller 94 will strike the cam surface 95, ride over it and onto the plane surface 96. In this action the latch lever will be pivoted counterclockwise to eifect dislodgment of the latch dog. This camming action will occur in the cycle of the carriage block shortly after the time at which the pin block 49 would ordinarily move to the left to dis.- lodge the latch dog.

It is to be noted that since the picked card is pulled by the gripping rollers whereby the pin block 49 is caused to move with the card at the same rate of speed, the pins 53 do not score or scratch the cards in this movement. Small pin prick holes are all that remain in the picked card subsequent to the release of the pins from the card.

While an embodiment of the invention has been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes can be made in the design and arrangement of the Pa ts without departing from. the spirit and scope of the invention, as the same will now be understood by those skilled in the art; and it is my intent therefore to claim the inventionnot only as shown and described, but also in, all such forms and modifications thereof as may be reasonably construed to be within the spirit of the invention and the scope of the appended claims.

I claim:

1. An easel card feed mechanism comprising a table for supporting in a horizontal plane a stack of easel cards, a pair of gripping rollers supported slightly beyond an end of the table, reciprocating card picker means arranged below the table for engaging and advancing oneach cycle of operation the bottom card of the stack over the table to. the gripping rollers, the gripping rollers adapted upon receiving the advancing card to advance it free from the table; wherein the card picker means is characterized by a carriage block reciprocating in a horizontal plane, at a rate of speed slower than the peripheral speed, of the rollers, a bed of pins supported upon thev carriage block for vertical and sliding, horizontal movement relative thereto, means for vertically moving the bed of pins. to engage the bottom card of the pack, holding means responsive to the vertical movement of the bed of pins to releasably retain the latter in its vertically moved condition, the bed. of pins undergoing said sliding, horizontal movement, relative to said carriage due to the motion of the engaged card as it is advanced by the rollers, and means carried by the bed of pins cooperable with the holding means to, retract the bed of pins {from the engaged card in. response to said sliding, horizontal movement.

2. Aneasel card picking unit of the character described comprising a carriage block slidable inya horizontal plane on a pair of tracks, a vertically movable pin assembly disposed, above the block having a retracted position atop the block and an elevated card engaging position above the block, elevator means vertically slidable in the block for elevating the pin assembly to its card engaging position upon the application of upward, pressure to the elevator means, spring means normally loading the elevator means to a downward position wherein the pin assembly limits atop the block, and releasable latch means carried by, the block responsive to an elevational movement of the pin assembly to latch the latter in its elevated position; wherein the pin assembly includes a support fixed atop the elevator means, a pin bed horizontally slidable on the support, and means on the pin bed cooperable with the latch means in a predetermined horizontal, slid;- ing movement of the pin bed relative to the support to release the latch means whereby the pin assembly'is caused to be retracted by the spring means.

3*. The combination comprising a carriage block reciprocable in a horizontal plane, a card engaging pin asseirrblyydisposed above the block having a retracted position atop the block and an elevated position above'the block, elevator means depending from the underside of the pin assembly arranged for vertical sliding movement in vtlre block and having an external portion projecting below the block, spring means on the external portion urging the elevator means in a downward direction wherein the pin assembly is held in its retracted position, the elevator means being adapted upon application of an upward pressure to the, said external portion'to raise the pin assembly to its. elevated position, and releasable latch means carried by the block and responsive to the elevated movement of the pin assembly to latch the latter in its raised position, wherein the pin assemblyinclndes a support mounted atop the elevator means, a vcard engaging pin bed; mounted for slidable movement in a horizontal plane on the support relative to the block, and latch release means carried by the pin bed cooperable with the latch means upon a predetermined slidable movement of the pin bed relative to the support to release the, latch means from the pin assembly, whereupon suchrelease the elevator means is responsive to the load of the spring means to. drop thepinassembly to its retracted position.

4.. Card picking apparatus, of the character described comprising in combination a carriage block reciprocable in a horizontal plane over a predetermined distance, the reciprocable block being movable in a forward stroke to advance the card and a return stroke; a card engaging pin assembly disposed above the block having a retracted position atopv the block and an elevated card engaging position above the block; elevator means depending from the underside of the pin assembly, arranged for vertical sliding movement in the block, and having an external portion projecting below the block carrying spring means urging theelevator means, to its retracted position; lift means disposed at a predetermined point in thereturn stroke of the carriage block adapted to be engaged by both the elevator means and the carriage block in the movement of the latter and responsive to such engagement to raise the elevator means so as to elevate the pin assembly to its card engaging position; releasable latch means carried by the block and responsive to the elevated movement of the pin assembly to latch the latter in its raised position; the pin assembly in the latter position adapted to advance the card upon movement of the carriage block on a forward stroke 'from the lift assembly; and means engageable with the latch means at a predetermined point prior to completion of the forward stroke of the carriage block to disengage the latch means, whereupon the pin assembly in response to the load of the spring means acting on the elevator means is caused to drop to its retracted position.

5. Apparatus as set forth in claim 4 wherein the lift means comprises a bellcrank pivoted to a fixed support having a pair of arms formed at right angles to each other, one of the arms extending in the direction of the carriage block and carrying at its free end a roller, spring means urgingthe latter arm in a down direction, a stop limiting the arm in the latter direction to a horizontal position and, at a level wherein the bottom of the elevator means is adapted to override the roller, and the other arm extending upright and having an abutment engage:

able with the carriage block as the elevattor means rides over the roller, whereupon the latter action the bellcrank iscal lsed to. pivot and press the roller against the elevator means to elevate the latter and theassociated pin. assembly to card engaging position. i

6. Apparatus as in claim 5, wherein the abutment is a screw threaded in an end of the upright arm and adjustable in a direction toward or away from the carriage block.

7. Apparatus as in claim 4, wherein the elevator means comprises a pair of rods vertically slidable in the block, afiixed at their upper ends in the underside of the pin assembly and atlixed at their lower ends to a cross bar bridging the ends of the rods, and wherein the spring means is a coil spring disposed about each rod between the carriage block and the cross bar.

8. An easel card feeding machine of the character described including a horizontal table having a longitudinal slot over which a stack of easel cards are adapted to lie, 21 picker assembly below the table for picking a bottom card from the stack and advancing it over a foiward end of the table, and a pair of gripping rollers supported beyond the forward end of the table for receiving the picked card and advancing it further on; wherein the picker assembly comprises a track parallel to the table; a block reciprocable over the track at a rate of speed; an elevator means vertically slidable through the block; a horizontal platform carried by the elevator means above the block; a pin slide having vertically disposed card picker pins; the pin slide being mounted to the platform for vertical movement with the latter as a unit, and being slidable from a normal rear position on the platform to a forward position thereon; the elevator means having a raised position wherein the pins project through the slot of the table and are adapted to engage a bottom card of the stack and wherein this raised position the pins and associated pin slide are portable by the block lengthwise of the slot to carry the card over the table to the rollers; the elevator means having a retracted position wherein the pins are clear of the bottom card; a spring load constantly urging the elevator means to its retracted position; latch means pivotally carried by the block and adapted to be releasably set to hold the elevator means in its elevated position against the spring load; and a lug on the pin slide cooperable during a forward sliding movement of the latter with the latch means to release the latter whereupon the spring load is effective to retract the elevator means and withdraw the pins from the card; and the block reciprocable over the track at a rate of speed slower than the peripheral speed of the rollers, whereby in consequence of the gripping of a card by the rollers and advancing it onward the pin slide is caused to he slidably pulled forward relative to the block and effect by means of its lug release of the latch means.

9. In the combination including a picker assembly for picking a bottom card from a pack and advancing it onward, and a pair of gripping rollers for receiving between them the advancing card and advancing it further onward, wherein the picker assembly comprises a block reciprocating toward and away from the rollers at a rate of speed relatively slower than the peripheral speed of the rollers, a bed of pins, elevator means carried by the block for vertically raising the bed of pins to engage a bottom card of the pack, locking means for releasably locking the elevator means in its raised position, and spring means adapted to retract the elevator means and withdraw the bed of pins downward in a vertical plane from the card upon release of the locking means; a platform carried by the elevator means supporting the bed of pins for sliding movement of the latter from a normal rear position on the platform to a forward position thereon, the bed of pins adapted to be slidingly carried forward on the platform relative to the block by the engaged card consequent upon the latter being gripped and advanced by the rollers; and means on the bed of pins cooperable with the locking means during the latter forward movement to release the locking means from the elevator means, whereupon the spring means is eifective to cause retraction of the elevator means and co sequent withdrawal of the bed of pins from the card.

10. In easel card feed and advancing apparatus of the character described including means supporting a stack of easel cards, carriage means reciprocating below the supporting means, and a pair of easel card advancing coacting rollers rotating at a rate of speed faster than the peripheral speed of the carriage 511163118; pin card picker means carried by the carriage means for picking and retaining on each cycle of the carriage means a bottom card from the stack and advancing it into the rollers, means for effecting movement of the pin card picker means as a unit with the picked card relative to the carriage means at the rate of speed the picked card is advanced by the rollers upon reception of the card by the latter, and means for subsequently releasing the pin card picker means from the picked card while the latter is being advanced by the rollers.

11. In easel card feed and advancing apparatus of the character described including means supporting a stack of easel cards, reciprocating carriage means, pin bed means carried by the carriage means for picking and retaining on each cycle of the latter the bottom card from the stack and advancing it further on as the carriage means moves, coacting roller means adapted to receive the advancing card and to advance it further on at a rate of speed faster than the rate of speed of the carriage means, track means on the carriage means supportnig the pin bed means for sliding movement over the track means parallel to the path of movement of the card, whereby the movement of the card by the roller means is translated into a corresponding sliding movement of the pin bed means over the track means, and release means cooperable with the pin bed means during the sliding movement of the pin bed means to release the latter from the advancing card.

12. In easel card picking and feeding apparatus of the character described, a horizontal table having a longitudinally extending slot therein and supporting a stack of easel cards over the slot, a carriage reciprocable in a horizontal plane back and forth below the table, a support carried by the carriage having movement in a vertical plane relative to the carriage, a pair of tracks on the support extending parallel to the slot, a bed of pins mounted for sliding movement along the tracks below the slot and having a normal rear position on the tracks, means for elevating the support and as a consequence raising the bed of pins upwardly to engage through the slot the bottom card of the stack, releasable latch means automatically responsive to elevation of the support to releasably latch the latter in elevated position, means for reciprocating the carriage whereby the engaged card is carried by the bed of pins free of the stack over the table, the range of movement of the carriage being sufiicient to carry the card beyond the forward end of the table, a pair of coacting feed rollers adjacent, the forward end of the table having a peripheral speed greater than the speed of the carriage and adapted to receive the advanced card from the table and to advance it further on, whereby the movement of the card by the rollers is translated into a corresponding forward sliding movement of the bed of pins on the tracks, and means cooperable with the bed of pins during such sliding movement to release and drop the support and as a consequence withdraw the bed of pins from the card as the latter is being advanced by the rollers.

References Cited in the file of this patent UNITED STATES PATENTS 1,034,972 Brown N Aug. 6, 1912 1,281,099 Tomlinson Oct. 8,1918 1,396,531 Schofield Nov. 8, 1921 1,453,019 Molins Apr. 24, 1923 2,625,904 Dombrowski Jan. 20, 1953 2,640,695 Nelson June 2, 1953

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