US2749118A

US2749118A - Carton feeding device

Info

Publication number: US2749118A
Application number: US245778A
Authority: US
Inventors: Charles E Kerr; Robert K Galloway
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1951-09-10
Filing date: 1951-09-10
Publication date: 1956-06-05
Anticipated expiration: 1973-06-05

Description

`lune 5, 1956 c. E. KERR ET A| CARTON FEEDING DEVICE 5 Sheets-Sheet 1 Filed Sept. lO, 19.51

OOOOOOOOOOOOO -osx l ATTORNEY June 5, 1956 c. E. KERR ET AL CARTON FEEDING DEVICE 5 Sheets-Sheet 2 Filed Sept. l0 1951 Nlmiirhil INVENTORS CHARLES E. KERR ROBERT K. GLLOWY Bv kfvM/f ATTORNEY June 5, 1956 c. E. KERR ET AL 2,749,118

CARTON FEEDING DEVICE Filed Sept. lO 1951 5 Sheets-Sheet 3 5' 1 52 Q F IIS- El 37a 2a 33 2e /l s *Y 7 llll/ INVENTORS 30 cHAnLEs e. nenn 32 Rosan-r n. sALLowAv ATTORNEY June 5, 1956 c, E. KERR ET AL 2,749,118

' CARTON FEEDING DEVICE Filed Sept. lO, 1951 5 Sheets-Sheet 4 :I1-"I E El 24, s da l E 2S i237 ad i L5- 3e L Q35 35 27 se VBI :'I E# 7 28 /32 mvENToRs 2S CHARLES E. ERR

'34 noasnr n. sALLowAY BY Mw ATTORNEY .lune 5, 1956 Filed Sept. l0 1951 C. E. KERR ET AL CARTON FEEDING DEVICE 5 Sheets-Sheet 5 E'IE E INVENTORS CHARLES. E. KERR ROBERT K. GALLOWAY BY All/4 ATTORNEY United States atent CARTN FEEDING DEVICE Charles E. Kerr and Robert K. Galloway, Hoopeston,

Ill., assignors to Food Machinery and Chemical Corporation, San Jose, Calif., a corporation of Delaware Application September 10, 1951, Serial No. 245,778

9 Claims. (Cl. 271--12) This invention relates to a carton feeding device for use in handling cartons in flat or collapsed condition and especially for use with cartons covered with parafn or made otherwise relatively stiff. A machine of this general character for use in connection with paraflined cartons is shown in co-pending application entitled Carton Opening Mechanism tiled August 21, 1951, with Serial No. 242,951 by Charles E. Kerr. Cartons for use in the machine disclosed in the mentioned co-pending application and referred to herein are customarily received at the point of use packed in such a way that the cartons are collapsed with the adjacent sides sometimes adhering or cohering because of the coating of paraffin or other comparable material. Additionally, the collapsed cartons themselves may be relatively heavy and stiif and tend when arranged in a le or column not to remain in a straight line but rather to buckle and curve. The individual cartons themselves, though ideally at when collapsed, actually take on a concavity or curvature and so force the entire column to be irregular and bend.

It is therefore an object of the invention to provide a carton feeding device effective to handle collapsed cartons satisfactorily even though the cartons are not flat, but are buckled or curved.

Another object of the invention s to provide a carton feeding device capable of taking cartons in succession from an irregular column.

A further object of the invention is to provide a carton feeding device elfective to feed one collapsed carton at a time from a column of adjacent, possibly adherent,

cartons.

A still further object of the invention is to provide a carton feeding device easily loaded or charged with collapsed cartons.

An additional object of the invention is to provide a carton feeding device easily inspected, cleaned and serviced.

y Another object of the invention is to provide a carton feeding machine useful in connection with a concurrently operating carton handling machine.

A further object of the invention is to provide a generally improved carton feeding machine.

Other objects are attained in the embodiment of the invention described in the accompanying description and illustrated in the accompanying drawings, in which Figure l is a plan of a carton feeding device constructed in accordance with the invention, a portion of the associated carton handling mechanism also being disclosed and parts of the ligure being broken away to reduce its size. v Figure 2 is a side elevation of the mechanism shown in Figure l, parts of the associated carton handling mechanismbeing omitted andparts being broken away to reduce the size of the ligure.

t Figure 3 is a cross section through part of the mechanism yof Figure 2, the planes of section being indicated by the; line 3*-3 of Figure-.1. f

Figure 4 is a cross section of part of the mechanism,

ice

the plane of section being indicated by the line 4-4 of Figure 2.

Figure 5 is a cross section, the plane of section being indicated by the line 5 5 of Figure 1.

Figure 6 is a cross section, the plane of section being indicated by the line 6-6 of Figure 1, and

Figure 7 is an isometric enlargement, parts being broken away, of part of the presser pawl mechanism.

While the carton feeding device can be embodied in a number of different ways depending upon the particular kind of carton with which it is to be utilized and depending also upon other Variable factors, it has successfully been incorporated in connection with a carton handling machine such as shown in the above mentioned co-pending application, and as partly illustrated herein.

ln the present instance, the mechanism is primarily designed for use with cartons which do not necessarily rest in a substantially straight column, yet which must be handled expeditiously and consistently in order to take care of the machine being fed and in order not in any wise to interrupt the smooth operation of the continuously working structure. This is primarily for the reason that the mechanism with which the carton feeding device is utilized operates at sustained high speed.

As shown in Figure 1, the structure includes a general framework 6 supporting a rotating wheel 7 having a plurality of carton holders 8 thereon. The rotation of the wheel 7 is eiiectuated by any suitable sort of driving mechanism (not shown) which also serves as a source of driving power for the carton feeding device as shown in the above identified application.

The framework 6 has an extension that forms a table 11 serving as a support for the base 12 of a carton magazine frame. A pair of

upstanding brackets

13 and 14 are removably secured to the magazine base 12. The brackets are elongated to provide

side walls

15 and 16, the side walls being in mirror symmetry about a central axis. The side walls extend substantially beyond the table 11 and in general constitute the confining side walls of the carton magazine. They are provided with removable low-friction liners 15a and 16a.

The lower wall of the magazine is in effect formed by a pair of

rods

17 and 18, each of which is constructed with a support foot 19 extending through a clamp boss 21 forming part of the magazine base 12 and held in vertically adjusted position therein by a fastener 22. By appropriately setting the

brackets

13 and 14 on the magazine base 12 to accommodate the lateral dimension of the carton and by appropriately clamping the feet 19 at an appropriate vertical height to accommodate the vertical dimension, cartons of various sizes within set limits can readily be held by the magazine. The collapsed cartons are arranged therein with the general plane of each carton (even though it may be concaved) in a vertical direction and extending as nearly as may be transversely of the magazine. The bottom edge of the carton rests upon the

rods

17 and 18 so that substantially the entire weight of the cartons is borne by said rods. The lateral confinement of the cartons is etectuatcd by close contact between the side edges of the cartons and the liners 15a and 16a of the

side walls

15 and 16 on the

brackets

13 and 14. l y

The collapsed cartons, due to their inherent resiliency and stiffness and sometimes due toa coating or adhesions, tend to spring into a concaveshape. Thereforea load for the magazine is strictly not a rectilinear column but tends rather to become a curved -column irregularly spaced and unstable unless confined and specially handled. For that and for other reasons, the. carton magazine is provided with a pair` of presser pawls 26 and f 27 on one side and .a similar but independent pair of presser pawls on the other side.

As especially shown in Figure 7, each of the presser pawls such as 26 is appropriately curved and is mounted to swing into and out of the magazine over and under the walls and 16, respectively. The movement is about the axis of a pivot bolt 28 extending through an ear 29 forming part of one of a pair of

independent carriages

30 and 31. Since the

carriages

30 and 31 on each side of the magazine are images, the description of one applies equally to the other. Each carriage has a generally flat body 32 around one edge of which springs 33 and 33 are hooked. These springs arranged 'to bear against the

presser pawls

26 and 27, respectively, to urge them toward the center of the carton magazine. This inward movement of the pawls is stopped by

flat extensions

34 and 34 on the pawls 2.6 and 27 which abut ribs 32a and 321), respectively, on the body 32'.. The pawls 26 and 2.7 can be depressed against the urgency of

thc springs

33 and 33 out of the space enclosed by the

side walls

15 and 16 but normally are projected by said springs into a location iu rearward abutment with cartons disposed in the magazine framework.

The

carriages

30 and 31 slide or reciprocate on the framework. To that end, each of the side walls 1:3' and 16 is provided with oppositely directed

rails

35 and 35 defining grooves 36 and 36', respectively, in which pairs oi

anti-friction rollers

37, 38 and 37', 33 are conned. The rollers are mounted on the body 32 for rotation so that the entire carriage travels to and fro on the side walls in a rectilinear path. Each of the carriages separately movable either manually by means of an upwardly extending hand grip 37a or may be arranged to be normally urged longitudinally of the framework in the direction of the carton discharge end thereof. For the latter purpose a exible cable 41 is at one end connected to the body 32 and is trained over a grooved pulicy 42 pivotally mounted on the

adjacent bracket

13 or 14 as the case may be. At its other end the cable is secured to a weight 43. With this arrangement, either of the carriages with its pair of

presser pawls

26 and 27 can be retracted by hand to the extremity of the rails and and then can be released against cartons put into the magazine, or both of the carriages can be simultaneously actuated by an operator and will press against a carton column even though it is irregular.

In the normal reloading of the magazine, cartons ahead of the presser pawls 26 and 27 are left in position. An additional charge of cartons, in generally columnar arrangement, is deposited between the

walls

15 and 16 and upon the

support rods

17 and 18 behind the extended pawls 26 and 27. Then, while the operator holds the new charge of cartons upright, he withdraws one of the carriages by grasping the hand grip 37a and pulling it to the extremity of the rails 35 and 35'. As the carriage passes by the new charge of cartons, the

pawls

26 and 27 are depressed and then spring in again just behind the new charge of cartons. The retracted car riage is released, and a similar operation is performed with the other hand grip and with the other carriage on the other side of the magazine.

Finally both pairs of presser pawls are engaged behind the newly extended carton column and both are effective upon the positioned cartons to urge the entire column in the magazine inwardly of the framework. This action occurs despite the fact that the last carton in the column may not be exactly perpendicular to the axis of the column and even though the cartons may be somewhat bowed and disposed at diterent distances from the framework on opposite sides. Since the separate pairs of presser pawls can engage immediately with the cartons and follow them as they are fed into the machine, accommodation is made for the possibly irregular shape and disposition of the carton column.

It is desired to feed the collapsed cartons one at a time from the end of the column inboard of the described framework, but that action is sometimes hampered not only by adhesions between successive folded cartons but also by the curvature or concavity of the cartons which do not readily yield to the customary treatment. For that reason, a special feed arrangement is provided.

A5 shown in Figure 6, on the framework 6 there is provided a drive shaft 50 having its axis disposed substantially vertically and arranged to revolve in journals Si formed on a bracket 52 extending from the side wall 16. The shaft 50 is provided with a drive gear 53 suitabiy arranged to operate in synchronism with the same drive that rotates the wheel 7.

The drive shaft Si) is designed to serve as a mounting for a swing frame 54. Included in the swing frame 54 is a pair of hubs 56 and 57. The swing frame is extended to an outboard fork 58. An adjusting screw 59 having a lock nut 61 not only engages the outboard fork on the swing frame but also engages with a web 62. forming part of the bracket 13. By this arrangement, when the screw 59 is disengaged from the web 62, the swing frame can be rotated about the axis of the shaft 56* toward and away from the bracket 13. These parts can be arranged either in ciosc relationship for normal operation or can be swung apart for inspection or cleaning and the like. Ordinarily, the screw 53 is engaged and is adjusted so that the swing frame is substantially parallel to the transverse piane of the carton magazine and is arranged across the magazine and is in registry with but is slightly separated from one end of the magazine to leave a space therebetween.

Mounted on the drive shaft 50 between the hubs 56 and 57 of the swing frame are

sprockets

66 and 67 driven in unison with the drive shaft by sot screws 63 engaging the shaft.

Parallel conveyor chains

71 and 72 are trained about the

sprockets

66 and 67 and are driven thereby. The chains are also trained around

sprockets

72 and 73. These are rotatably mounted on a non-rotative shaft 74 having straddle-milled end portions 74n and 74h seated within bifurcate bearings 76 and '77 formed on the outboard fork 58 of the swing frame. Adjusting

devices

78 and 79 carried by the straddle-milled end portions 74a and 74h serve to effect adjustment of the shaft 74 relative to the outboard fork 58. The arrangement is such that when the drive shaft 5G is revolved, the two

chains

71 and 72 are advanced in unison. The

adjustments

78 and 79 insure that the chains can be maintained at the proper tension. Since the

chain sprockets

66 and 67 are concentric with the mounting of the swing frame, the frame can be moved into and out of operating position without interfering with the drive mechanism.

In accordance with the invention, each of the

chains

71 and 72 is provided at an appropriate interval, depending upon the timing arrangement of the mechanism, with one of a plurality of propulsion lugs 81 incorporated in the body of the chain and having a projecting hook 82 especially designed to engage the trailing edge of the leading carton from the column of cartons in the carton magazine. The direction of advance of the chains 71 and 71' is such that the tendency of the lugs 81 is to force a carton from the magazine toward the receiving wheel 7.

A practical diiculty has been that the cartons often approach the pair of chains, not in the planar fashion but in an inclined relationship and sometimes with the cartons concaved or curved in such a way that they tend to buckle rather than to advance. Sometimes they are so curved or displaced that they are not appropriately engaged by the hooked lugs 81.

To overcome these and other troubles, there is provided on the swing frame means for subjecting at least part of an adjacent carton to a subatmosphcric pressure or vacuum so that the carton, no matter how distorted it is as it approaches the feed chain, is made to assume a planar and substantially perpendicular relationship so that it can be properly engaged and carried away by the lugs 81 on the

chains

71, 71. This assures appropriate engagement with the conveyors without buckling and without crowding the operation of the feed mechanism.

Disposed in the swing frame is a vacuum box 91, especially shown in Figures 3 `and 4. The vacuum box is preferably defined by rectangularly disposed walls 92 integrally incorporated with the swing frame. The vacuum box walls 92 lead to a tubular connection 93 to which a flexible hose 94 is connected. The hose extends to any suitable source of moderate subatmospheric pressure or vacuum. The extent of the subatmospheric pressure is not particularly great being only suiicient to draw an adjacent carton toward the vacuum box without holding the carton so securely that it cannot be simultaneously advanced by the lugs on the chain mechanism.

It is desired that a carton urged toward the vacuum box be maintained in a planar condition. This is facilitated by the provision on the vacuum box of a grid 96 including a pair of coplanar side rails 97 and 98 extending transversely across the upper and lower end of the magazine in a plane in front of the general structure of the chains 71 and 71', but behind the tops of the hooked lugs 81. Supplementing the

rails

97 and 98 in forming the grid 96 are rods 99 spanning one side of the box 91. These help to correct distortion of the container pressed against the grid by the vacuum and by the pairs of

pawls

26 and 27 on the

carriages

30 and 31 that force the cartons forward due to the effect of the weight 43. This structure provides an arrangement in which the leading or exposed carton, even though displaced and deformed, is flattened against the grid 96 and is consequently properly oriented in a perpendicular plane and in a generally planar shape and configuration, as distinguished from a concave or distorted shape.

The arrangement of the vacuum box 91, of the

rails

97 and 98 and of the rods 99 establishes in effect a planar surface against which the cartons are held by vacuum. Stated differently, there is provided a grid in the form of members terminating substantially in the same plane and defining apertures therebetween. No matter how the vacuum arrangement is considered, it has the effect of holding a previously concave or distorted or warped carton in substantially planar shape or condition against the grid in the space between the end of the carton magazine and the grid.

To assist in supporting a carton by contact with its lower edge as it approaches and leaves the grid, there is provided on the framework a slide bar 100 mounted substantially coplanar with the

rods

17 and 18 on an adjustable support 101. The timing of the chains 71 and '71 is such with respect to the operation of the shaft S0 and with respect to the operation of the adjacent carton receiving wheel 7 that a pair of the hooked lugs 81 engages at an appropriate time vWith the trailing edge of the carton attened against the grid and resting on the slide bar 100. As the chains advance, the hooked lugs advance the carton simultaneously overcoming the frictional load caused by the vacuum without undue difiiculty. As soon as one end of the advancing carton clears part of the apertures of the grid, there is a corresponding vacuum release of that carton, and the vacuum then becomes effective on the next superposed carton in the carton magazine.

To make sure that only one carton at a time is displaced from the magazine, the space between the bracket 14 and the grid 96 is adjustably defined by a gage plate 102 secured in position by fastenings 103 operating in slots in the bracket 14. The eiect of this arrangement is that there can be left an intervening opening or space 104 (Fig. 4) having a dimension just sufficient to pass a carton of the thickness being employed and far too small to permit the passage of more than one carton at a time.

The advancing carton passing through the opening 104 is further guided and propelled pursuant to the invention.

For that reason, the framework 6 is provided with an upright spindle 10S carrying a pair of spaced and knurled guide rolls 106. In opposition to the rolls 106 is a pair of rotatable guide rolls 107. Each of the rolls 107 is carried in one of a pair of forked lever arms 108 secured by journal pins 109 to appropriate ears 111 extending from the hubs 56 and 57 of the swing frame.

To provide variable spacing between the rolls 106 and the rolls 107 so as to accommodate minor irregularities in the cartons being advanced, each lever 108 is provided with an extension 112 which bears against one end of a spring 113 that is seated against a projection 114 extending from the swing frame. The shaft with its rollers 106 is constantly driven at a speed that is appropriately related to the operational speed of the carton handling wheel 7 and the effect of the described mechanism is to act as a further guide and driver for the cartons initially advanced by the

chains

71 and 71 to carry them individually in succession and an appropriate direction toward the mechanism 7.

By this invention there is afforded a structure readily applicable to a carton handling machine for use in feeding cartons apt to assume some shape other than planar. The feeding device is effective to permity the initial stowage of groups of cartons in a column from time to time without difliculty on the part of the operator. The carton feeding device is effective to straighten the cartons which may have become concaved or caught or out of position, and to hold them in flat relationship against a supporting grid. The cartons are not only supported in planar condition but they are held with their general plane vertically and without falling or dislodging by gravity. The carton so held is readily advanced by the conveyor, being only releasably retained in an appropriate position against the grid by vacuum or subatmospheric pressure. Finally the carton is advanced between guide rollers into an appropriate location for use by succeeding machinery. The machinery is adjustable for different sized cartons. The

Vacuum mechanism, being movably mounted, can be swung out of the way for servicing or cleaning or inspection of the interior. The device meters the discharge to but a single carton at a time, yet operates quickly and effectively, even with deformed cartons and those having adherent coatings upon them, to furnish a steady service of individual cartons properly oriented for subsequent use.

We claim:

l. A carton feeding device comprising a framework, a carton magazine on said framework, a drive shaft journalled in said framework, a swing frame journalled `on said drive shaft, a grid on said swing frame registering with -said magazine, a countershaft joumalled in said swing frame, sprockets on said drive. shaft and said countershaft, conveyor chains on said sprockets extending alongside said grid, guiding means spaced laterally from said magazine, and stop means holding said swing frame in predetermined position of rotational adjustment about said' drive shaft, said stop means being adjustable to align said conveyor chains with respect to said guiding means.

2. A carton feeding device comprising a framework, a carton feeding magazine on said framework, a swing frame, means for mounting said swing frame on said framework for pivotal movement about an axis at onel side of said magazine, means for releasably holding said swing frame in selected position of rotation about said axis and in registry with said magazine, a conveyor on said swing frame adapted to advance transversely of said magazine in a direction substantially perpendicular to said axis, and means for driving said conveyor.

3. A carton feeding device comprising a framework, a Vacuum box on said framework, a grid spanning said vacuum box, means for advancing a carton toward said grid, means for sliding the carton over said grid, and means for pressing the carton against said grid with sufficient force to flatten the carton but with insuiiicient force to prevent sliding movement of the carton over said grid.

4. A carton feeding device comprising a hopper adapted to support a stack of upright folded cartons, said hopper having spaced sidewalls and a bottom wall providing an open forward end, a centrally apertured abutment wall disposed opposite the forward open end of said hopper in confronting relation with cartons in the hopper, means mounting said abutment wall for adjustment toward and away from the forward end of the sidewalls to a distance greater than the thickness of one carton but less than the thickness of two to define a discharge zone between the hopper and the wall, a grill disposed over the central aperture of said wall, the outer edges of said grill being in the vertical plane of the face of the wall, air suction means operatively associated with the central opening in said wall for positioning the foremost carton in said stack in flat abutting Contact with the face of said wall and with said grill and entirely Within said zone, and a pair of vertically spaced endless chain conveyors operatively mounted on said wall above and below said grill and having lugs extending into the discharge zone a distance sucient to engage only the foremost carton in said stack.

5. A carton feeding device comprising a hopper adapted to support a stack of upright folded cartons, said hopper having spaced sidewalls and a bottom wall providing an open forward end, an apertured flat abutment wall disposed opposite the forward end of said hopper in confronting relation with cartons in the hopper, means mounting said abutment wall for rotational adjustment about a vertical axis, said abutment wall being spaced from the forward end of the sidewalls a distance greater than the thickness of one carton `but less than the thickness of two to define a discharge zone between the hopper and the wall, air suction means operatively associated with the apertures in said abutment wall for positioning the foremost carton in the stack in fiat abutting contact with said abutment wall and entirely within said zone, an endless chain conveyor operatively mounted on said abutment wall adjacent said discharge zone and having lugs movable laterally through said zone and projecting into the zone from the abutment wall side a distance sufficient to engage only the foremost carton in said stack, a guide roller mounted for rotation about an upright axis offset laterally from said hopper in such position that the plane of said zone is substantially tangential to the roller, and adjustable stop means for holding said abutment wall in selected fposition of rotational adjustment about said axis to retain the wall with its plane in predetermined relation to said roller.

6. Apparatus for positioning folded cartons in a carton feeding machine comprising a vacuum box having an opening in a forward wall, a plurality of spaced, parallel rods disposed across said opening to provide a planar surface, a support `.cmber disposed below said opening und extending normal to said planar surface and adapted to receive thc lower edge of an upright folded carton,

means for subjecting said box to subatmospheric pressure to hold a carton disposed on said support against said rods in a flat planar position, and means for sliding on the rods in a direction parallel thereto a carton held at against the rods.

7. A carton feeding device comprising a magazine for a supply of folded cartons, a swing frame arranged in confronting relation to cartons in the magazine and mounted for rotational adjustment about an axis at one side of the magazine, a conveyor on said swing frame adapted to advance one folded carton at a time laterally from the magazine in a direction parallel to the frame, guide rolls mounted for rotation about axes laterally outward of the magazine in position to receive between the rolls a folded carton advanced from the magazine by said conveyor, and means for compensating for curvature of folded cartons advanced by said conveyor toward said guide rolls comprising adjustable stop means for holding said swing frame in selected position of rotational adjustment about said axis.

8. A carton feeding device comprising a magazine adopted to support a supply of folded cartons and having `an open discharge end, a swing frame arranged transversely of the magazine in spaced relation from the discharge end of the magazine to define a discharge zone between the frame and magazine, means mounting said frame for rotational adjustment, a conveyor on said frame adapted to successively advance folded cartons laterally from thc magazine, means causing the foremost folded carton in said stack to be pressed at against said swing frame with pressure yieldable to permit said conveyor to move laterally a carton pressed against the frame, rotatably mounted guide rolls offset outward of said magazine in position to receive folded cartons advanced from the magazine by said conveyor, and means for compensating for curvature of a portion of a folded carton extending laterally from said swing frame toward said rolls comprising stop means for holding said swing frame in selected position of rotation adjustment.

9. A carton feeding device comprising a magazine adapted to support a supply of folded cartons and having an open discharge end, a swing frame arranged transversely of the magazine in spaced relation from the discharge end of the magazine to define a discharge zone between the frame and magazine, means mounting said frame for rotational adjustment, a conveyor on said frame adapted to successively advance folded cartons laterally from the magazine, a vacuum mechanism elfective to cause the foremost folded carton in said stack to be pressed at against said swing frame with pressure yieldable to permit said conveyor to move laterally a carton pressed against the frame, rotatably mounted guide rolls offset outward of said magazine in position to receive folded cartons advanced from the magazine by said conveyor, and means for compensating for curvature of a portion of a folded carton extending laterally from said swing frame toward said rolls comprising stop means for holding said swing frame in selected position of rotational adjustment.

References Cited in the tile of this patent UNITED STATES PATENTS 769,927 Zeh Sept. 13, 1904 907,944 Abrams Dec. 29, 1908 2,055,245 Werner Sept. 22, 1936 2,161,124 Babicz .Tune 6, 1939 2,191,586 Richard Feb. 27, 194() 2,572,509 Novick Oct. 23, 1951 2,621,928 Lauffer Dec. 16, 1952 2,624,576 Lauffer Jan. 6, 1953