US2585941A - Staple magazine and feed means for pneumatic staplers - Google Patents

Description

G. JUlLFs 2,585,941 ZI FEED MEANS TAPLERS 2 SI'lEETS-Sl-IEET l NE AND ATIC S A. STAPLE MAGA FOR PNEUM Feb. 19, 1952 Filed Nov. 25, 1949 N. NMI WMI. lINMv ATTORNEYS.

Feb. 19, 1952 A. G. JUILFS STAPLE MAGAZINE AND FEED MEANS FOR PNEUMATIC STAPLERS 2 SHEETS-SHEET 2 Filed Nov. 23, 1949 W/ x m. ES... l, w. Q

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AT 'TO R N EY5- Patented Feb. 19, 1952 STAPLE MAGAZINE AND FEED MEAN Si F R PNEUMATIC STAPLERS Albert G. Julfs, Newtown, Ohio, assignor to Senco Products, Inc., Cincinnati, Ohio, a corporation of Ohio Application November 23, 1949, Serial No. 128,941

Claims.

My invention relates to a staple magazine and feed means for pneumatic staplers primarily for stapling upholstery to the interior of automobile bodies Where the staples must be driven in a confined space, in corners and in crevices, and where the rapidity of inserting the staples is of great importance. Upholstery, particularly in automobile interiors, is fastened to the wood framing by two-pronged staples which must be driven firmly into the Wood of the frame so that the upholstery Will not pull loose and which must be completely driven so that the head or bend of the staple does not project and catch on the clothing of the passengers. Due to the configuration of the interior of the normal automobile, the fabric upholstery is usually fastened in the crevices surrounding the padding and in hidden corners and crevices so that the staples themselves cannot be seen and thus mar the finished appearance of the interior.

Reference is herein made to the following copending patent applications of Which I am the sole inventor and in which application Serial No. 181,023, Staple Drive Mechanism for Portable Pneumatic Staplers, filed August 23, 1950, is a division of this application; and Serial No. 181,024, Staple Feed Mechanism for Portable Pneumatic Staplers, led August 23, 1950, and issued as U. S. Letters Patent No. 2,585,942 on February 19, 1952; Serial No. 181,025, Staple Driving Means for Portable Pneumatic Staplers, filed August 23, 1950, and issued as U. S. Letters Patent No. 2,585,939 on February 19, 1952; and Serial No. 181,026, Valve Control System for Portable Pneumatic Stapler, filed August 23, 1950, and issued as U. S. Letters Patent No. 2,585,940 on February 19, 1952, which are directed to related subject matter.

While my novel portable pneumatic stapler is primarily for use in fastening the upholstery on the interior of automobiles, it. of course, may be used for fastening upholstery on furniture as well, and in any other field Where the driving of staples rapidly and in relatively large quantities is of importance.

It is an object of my invention to provide a portable pneumatic stapler which will fullydrive completely into the supporting frame, does not 2 cut or mar thel textile material or upholstery being fastened to the frame.

Another object of my invention is to provide al portable pneumatic stapler which is convenient to transport and handle and which is almost `foolproof in operation and avoids any chance of misfire upon the pulling of the trigger, and which signals the emptying of the staple carrier by making the action of the stapling gun inoperative.

Another object of my invention is to provide a portably pneumatic stapler having all of the above advantages, but which is compact as to the gun itself and the track carrying the load of staples, but which holds and drives a great many staples, thus permitting the continual use of the staple gun before the necessity of reloading.

These and other objects of my invention which will be set forth hereinafter or Will be apparent to` one skilled in the art upon reading these specifications, I accomplish by that certain construction and arrangement of parts of which I shall now describe an exemplary embodiment.

Reference is now made to the drawings which form a part thereof and in which:

Figure 1 is a front elevation of my novel pneumatic stapler.

Figure 2 is a longitudinal cross section of my novel stapler taken on the section line 2 2 of Figure 1.

Figure 3 is a plan view of my novel stapler with a portion broken away to show a part of the interior. l

Figure 4 is a cross section of the nose of my stapler taken on the section line 4 4 of Figure 2.

Figure 5 is a cross section of the driver chamber of my novel stapler taken on the section line 5 5 of Figure 2.

Figure 6 is a cross section of the staple track of my stapler taken on the section line 6 6 of Figure 2.

Figure 7 is a front elevation of the staple pushing shoe taken on the section line 1 1 of Figure 2.

Figure 8 is a rear elevation of my novel stapler.

Figure 9 is a cross section of my stapler with the piston, rod, and staple driver in its final position after driving a staple and taken on the section line 9 9 of Figure 8.

Figure 10 is a cross section of the staple feeder latch taken on the section line Ill-I0 of Figure 9.

Figure 11 is a cross section of the end of the staple track and staple receiving slot with the staple moving shoe in the empty position,

asaoci Figure 12 is a plan View of the piston rod and staple driver slot.

Figure 13 is a perspective view of the removable closure portion of the slot housing.

Figure 14 is a plan view of the end of the piston rod and the staple driver used in my stapler.

Figure 15 is a sectional view takenon the line I-I 5 of Figure 2. v

Briefly in the practice of my invention, I provide a portable pneumatic stapler which consists of a pneumatic cylinder carrying a free sliding piston. A piston rod contacting but disconnected to the piston runs from the interior of the cylinder to a staple driver which is mounted in a slot in which each individual staple to be driven is positioned by means of the staple feeder.

The inlet aperture for the compressed air enters the cylinder at a position below the head of the cylinder and is covered by the piston when at rest. There is a small groove in thevcylinder wall which carries the air tothe head of the cylinder behind the piston. When air is released to the cylinder, the piston prevents the direct owing of the air through the large inlet aperture, but a small portion ows through the groove in the cylinder wall and moves the piston to the left relatively slowly. The piston in turn moves the piston rod and the staple driver up to the staple which is positioned in the slot. The proportioning is such that after the piston has moved the staple driver into contact with the staple, the relatively large inlet port is uncovered and a large amount of compressed air enters the cylinder behind the piston, urging it rapidly to the left. This action drives the staple along the slot and out the nose of the gun. The piston moves rapidly to the left and the air before it is exhausted through a port in the cylinder wall. As the piston passes the port, a resilient air cushion is set up between the piston and the forward end of the gun. LThis prevents the piston from contacting the end of the cylinder too hard and stops its movement. Since the piston rod is not fastened to the piston itself, its inertia carries it beyond the point where'the piston stops and the end of the staple driverv is projected slightly beyond the nose of the slot, thus insuring the driving home of the staple, even if the nose of the gun is slightly spaced from the fabric frame.

In the handle of the stapler, I provide an air chamber of appreciable size which permits the building up of the volume of the compressed air prior to its release into the cylinder. This permitsthe use of relatively small air lines thus making the stapler easier to use.

AThe staples themselves. are loaded on a track which is formed as a portion 'of the circumference of a circle. I provide an arm which projects readily from the track and inwardly to a center point on the body of the gun and which is urged towards the row of staples by means of a piston actuated by compressed air feeding from the chamber in the handle 'and controlled by a valve. The piston forces the arm and the foot mounted on the end of the same which rides in the track behind the rearwardmost staple to the left of the drawings, thus pushing the rst staple up into the slot in the front of the driver. As the staple leaves the slot and the staple driver is withdrawn, the following staple takes its place. When the last staple has been driven, there is an ear lon the shoe which follows the staples, which slipsl up into the slot and prevents the staple driver from further movement to the left 'and 'ee'ct jamming the gun, thus indicating to the operator that there are no more staples on his track.

Referring to the drawings, I provide a cylinder I in the body housing 2 of my portable stapler. Within the cylinder I is a piston 3 which is at rest against the cylinder head 4 when the stapler is not in operation.

A piston rod 5 runs out of the cylinder I into a slot 6 and is urged against the piston 3 by a helical spring I which is based in a slidable collar` or retaining cup 8. On the end of the piston rod 5 is mounted a staple driver 9. The staple driver 9 has a hole on one end which slips over a boss I0 on the end of the piston rod 5. The driver 9 reciprocates in a slot II which is formed in the nose I3 of the stapler, the end of the nose and `slot being open as indicated at I2 in Figure 2.

An inlet port I4 runs from the trigger valve 55 to the cylinder wall I. The port I4 is located a predetermined distance from the cylinder head 4 and is covered and sealed by the piston 3 when the piston is in its operative position, as shown in Figure 2. A narrow groove I5 (see also Figure 15) A runs from the port I4 to the head 4 of the cylinder I, and I preferably provide an annular opening I6 around the head 4 to permit the small amount of air passing through the groove I5 to flow behind the piston 3.

In the wall of the cylinder I an appreciable distance from the opposite end of the cylinder, I provide an exhaust port I'. This exhaust port I' permits the air in the cylinder I to escape as the piston 3 moves to the left. However, when the piston 3 slides over and seals the port I', a resilient cushion of air is built up between the piston 3 and the forward end of the gun as blocked by the cup 8. This cushions further movement of the piston 3.

In the handle I'I of the stapler there is provided a relatively large air chamber I8 which permits the compressed air flowing into the handle from the connection I9 to build up in volume.

When the trigger is actuated and moved to the position shown in Figure 9, air flows from the chamber I8 through the passageway I4. Since this passageway is sealed by the piston 3, the air does not directly flow into the cylinder from the port I4. However, a small amount ows through the groove I5 and into the annular space I6 behind the piston 3. This moves the piston 3 at a relatively slow rate to the left in Figure 2.

A staple has been fed into the slot II by the staple feeder at a spot 20 just ahead of the staple driver 9. The distance between the port I4 and the cylinder head 4 is approximately the same distance as the end 9 of the driver 9 from the point 20 where the staple rests in the 'slot II. Fr'om this, itis apparent that when the piston 3 moves relatively slowly to the left pushing the piston rod 5 and the staple driver 9 to the left. this slow movement is of a distance sufficient to pickV up the staple. This relatively slow pickup prevents jamming. At this point, the'piston 3 has uncovered the port I4 which permits a relatively heavy i'nrush of compressed air behind the piston 3. This drives the piston 3 to the left and the air in the cylinder before it exhausts through the port I. The piston rod 5 and staple driver 9 move rapidly/to the left, driving the staple out of the nose of the gun and into the work. The

`piston 3 is stopped by the resilient cushion of air "built upbetween it and the forward end of the "gun after the piston 3 has sealed the port I". "A washer 2| is provided in the 'forward endet the cylinder I to assist in stopping the piston 3. However, the piston 3 is substantially stopped by the cushion of air before it reaches the washer 2 I. This cushion of air is built up when the piston 3 blocks the port I1 and when the rod 5 has advanced so as to substantially fill that orifice in the cup 8 through which it just nicely slides, all as best seen in Figure 8. Air trapped between the piston 3 and the forward end of the gun, as closed by the cup 8 and rod 5, provides the desired cushion. Although some of the trapped air may leak out around the rod 5 through the orifice in cup 8 as the piston 3 advances, a substantial cushioning affect is still obtained because that volume of air moved forward by the piston 3 is quite large relative to whatever volume there is that could possibly escape around the rod 5 as above described. The inertia of the piston rod 5 carrying the driver 9 is such that it carries on after the rod 5 leaves the piston 3, as shown in Figure 9. This permits the end 9 of the driver to project beyond the nose I3 of the stapler. The spring 'I limits this movement of the piston rod 5 and also drives the piston rod 5 and the piston 3 back to its home position, as shown in Figure 2 when the air within the cylinder I exhausts through passageway I4, the trigger mechanism I5, and the exhaust passageway 22.

The cushioning of the piston 3 by means of the air compressed by it against the forward end of the gun prevents the piston 3 from hammering against the end of the cylinder and thus injuring the gun.

Occasionally, a defective staple gets into the slot I I of the gun or a staple may become jammed therein. In order to permit the removal of such a defective staple, I provide a removable closure 23 in the staple driveway surrounding the slot II. This closure 23 contains a. rounded portion 24 which slides under a part of the body 2 of the gun and abuts the spring retaining cup 8. The other end 25 of the closure 23 is wedge-shaped and snaps into a complementary aperture in a part of the nose I3, as is shown in the solid lines in Figure 2. When it is desirable to remove a defective or jammed staple, the closure 23 is moved to the right (as viewed in the various figures) against the tension of the spring 'I. This may be done by inserting a tool 26 in two holes 21 in the closure 23 and pushing on the tool with the finger. r

In the event the staple driver 9 should become bent or injured, it may be easily removed by pushing the closure 23 to the right (as viewed in the various figures) and lifting the end 25 up and out from under the aperture in the nose I3. as is shown in the broken lines in Figure 2. In this position, the closure 23 may be completely removed. This exposes the driver 9 which may be easily lifted out of its track and a. new driver 9 inserted in its place. Figure '12 shows the slot I I in which the driver 9 operates and this is made available when the closure 23 is removed.

One of the members forming a part of the nose I3 is indicated at I3a in Figure 2. This member I3a is shown in detail in Figures 5 and 12. As shown in these figures, the member I3a is channeled or grooved so as to provide the slot Il in which the staples are positioned and driven. The

-bottom of this slot is indicated at IIa in the forward end of the nose member I3a as shown in Figure 12.

Also, as is shown in Figures 5 and 12, the member I3a is provided with a pair of ledges I3b downwardly olset from the upper vsurface thereof.

These ledges project inwardly from the side walls' which define the slot I I. It is on these ledges I3b that the staple driver 9 rides, see especially Figure 5. As also shown in this figure, the closure member 23 rests on the upper surface of the nose member I3a, the staple driver just nicely sliding therebeneath on the ledges I3b.

The closure member 23 is provided with a slot 23a. (see Figure 5) which just nicely receives the piston rod 5 when it is advanced as above described. It should be noted that the side walls of this closure member 23 are quite thick; these side walls extend inwardly to such an extent that they completely overlie the ledges I3b. When a staple is brought iiatwise into the slot II, at the point generally indicated at 20 in Figures 2 and 12, this point being ahead of the forward ends of the ledges I3b, it comes into contact with the bottoms of the side walls of the closure member 23; i. e., the grooved closure member 23 limits upward movement of the staples. Thus when the driver 9 slides forward on the ledges I3b beneath the closure member 23, the piston rod at this time sliding within the groove 23a, it will contact the staple then in the groove II. This staple will be driven from beneath the closure member, against which it is initially maintained as above set forth, across the bottom I I, beneath the upper member of nose I3, and ejected from the gun as at I2.

The above is a description of the mechanism of the stapler which actually drives the staple. The trigger mechanism 55 is a valve of the usual type and its ports and operations which insure its ac tuation and permit the exhaust of the cylinderl is believed completely clear from the drawings, Figures 2 and 9. The connection I9 for the vhose is preferably of a swivel type as Vshown in the drawings, thus permitting the easy manipulation of the stapler by the operator. The mechanism, if necessary, may be easily serviced by removal of the parts and particularly the cylinder head 4 which is screwed into the body, as shown in the drawings. The control of the trigger 55 is maintained by a spring I5 which insures the return of the trigger to the position shown in Figure 2 for exhausting through port I4 when the finger is removed or relaxed.

A particularly important feature of my invention is the provision of the small groove I5 between the inlet port I4 and the cylinder head 4. By making this groove extremely small, such as .008 inches, I insure that the air will quicklyv flow through the groove I5 and insure the movement of the piston 3 at once. In other words, it is almost impossible to pull the trigger 55 so slowly as to permit the air to leak in behind the piston and fail to build up a moving pressure. The movement of the air through the groove I5 insures that the groove I5 remains perfectly clean and unclogged at all times. The clogging of this groove is further prevented by the movement of the piston which together with the groove forms a hole, the piston side of which is opened upon every movement of the piston.

The operation of the valve means is as follows. Air is admitted to the stapler as indicated at I9 in Figures 2 and 9. In Figure 2 the triggervalve 55 is shown in its normal or closed position. In this position the spring I5 maintains the valve 55 in the left hand (as viewed in Figures 2 and 9) portion of the sleeve 56 within which this valve slides. When this valve is so maintained the port 51 in the sleeve 56 is unobstructed and the mem'- ber 58 blocks the sleeve 56 so as to` prevent air, from the chamber I8, reaching the port'l4. This 7 is thel exhaust position. Thus air. which is between port I and cylinder head 4 is exhausted, on movementI of the piston 3 towards the head 4, through port I4 (and I5), around the valve plunger 59, through the port 51 and into the exhaust passage 22 in the handle I'I.

Movement of the valve 55 against the spring I' has the following effect. The body of the valve 55 blocks the exhaust port 51 and the member 58 is moved off the end of sleeve 56. Air then enters the port I4 around the valve member 58. This air cannot by-pass the port I4 and exit through the exhaust port 5l because this latter port is blocked by the body of valve 55, as is clearly shown in Fig. 9. A. small amount of air then passes through the small channel I5 and gathers behind piston 3. The piston is thereby slowly moved to the left until the port I4 is exposed at which point the bulk of the air enters behind piston 3 and moves it rapidly to the left. When the piston 3 moves past the port I it is stopped by a Acushion of air as above described.

I will now describe the staple feeding means which is an important part of my novel stapler.

Referring to Figure 2, a staple track 28 is attached at one end to the nose I3 of my gun and is curved, as shown in the drawings so that the other end 29 may be attached to the handle II of the gun. The operative portion of the track 28 conforms to a portion of the circumference of a circle. The track 28 is substantially square in cross section and contains a guard 38 spaced therefrom to hold the staples in a straddling position around the track 28. The curved track 28, in combination with the extended nose I3, makes possible the use of my staple'gun in confined quarters unexcessible to staple guns now known to me.

At a point 3I, which represents the center of the circle of which the track 28 is a portion of the circumference, I mount an arm 32 by means of a pintle at 3l. The arm 32 projects radially from the center 3| to the track 28 and is terminated by a shoe 33, which is in the form of a staple in cross section and which rides on the track 23 under the guard 30. As is apparent from Figure 2, the shoe 33 may be withdrawn to the right out from under the guard 38 to permit the loading of a row of staples on the track 28. Thereupon, the shoe 33 is positioned behind the last staple and under the guard 35, as shown in Figure 9.

In the body 2 of the gun and adjacent the point 3| to which the arm 32 is pivoted, I provide a cylinder 34 carrying a piston 35. There is a passageway 3B leading from the end of the cylinder 34 through a valve to a passageway 3l which is open to the chamber I8.

A yoke 38 pivoted to the arm 32 loops over the end 39 of the piston 35 and rides in a slot 48 where it is held by a pin 4 I. From the above, it is apparent that when air is permitted to iiow in the passageway 36, the piston 35 is moved to the left as shown in Figure 9 and the arm 32 is pulled to the left, thus forcing the shoe 33 against the row of staples which in turn forces the foremost staple into the slot II. By this means a continual pressure is exerted on the row of staples at al1 times during the operation of the gun when the valve 42 is in the position shown in Figure l0.

When the last staple has been driven, the leading edge 43 (see Figure 2) of the shoe 33 enters into the slot II, abuts against the bottoms of the side walls of the closure member 23, and is held in this position. This prevents the driver 9 from moving to the left end, in effect, jams the gun so the operatorwill know that he is out of staples. The position of the edge 43 of the shoe in the slot II is shown in Figure 11. When this condition is reached, the operator actuates the valve 42 which permits the air in the cylinder 35 to exhaust through the passage 36 and out through the clearance 44. This permits the return of the arm 32 with. its follower shoe 33 to the position shown in Figure 2 by hand so the track 28 may be again loaded with a new supply of staples.

A cross-sectional view of the valve 42 is shown in Figure 10 and is believed clear. The port 36 is shown and the port 45 is shown, which runs through the body 2 of the gun to the passageway 3l and then to the chamber I8, as shown in Figure 2. Fixed between the valve members 42 is a cylindrical member 60 of smaller diameter than the bore 6I in which it and the members 42 slide. On either side of the member are gaskets 62. When the valve members 42 are in the position shown in Figure 1G, the operative position of the valve, air passes from the chamber I8 into the passageway 3l, through the conduit 45, around the member 68, into the passageway 38 and into the cylinder 34, whereby the piston 35 is moved to the left (Figure 9) and the shoe 33 with it (through the yoke 38 and arm 32).

When the valve members 42 are moved to a position the reverse of that shown in Figure 10 the passageway 3l is blocked or cut off from the passageway 36 by one of the gaskets 62. This gasket will have cleared the passageway 36 so that air may bleed from this passageway around the reduced portion 44 of one of the members 42 and out of the gun. The arm 32 may then be returned to the position of Figure 2 as above described.

In actual practice, the tool 26 which is used to slide or remove the closure 23 is removable so there is no danger of its catching on trim and thus opening the closure 23 inadvertently.

From the above, it is apparent that I have provided a portable pneumatic stapler which is very sure in its operation and which drives a staple completely home without tearing the fabric and which is operable from almost any reasonable position. The nose is very slender so that it can be slid into small crevices and corners between the upholstery and molding of an automobile interior.

While in the above description and drawings I have described and shown a stapler and a feed therefor, it is to be understood that my stapler may be used for driving nails or brads, or with slight modification, for setting rivets.

While I have shown a feed, the arm of which is operated pneumatically, it may be preferable in some cases to operate the arm by means of a coil spring or the like. The provision of the track congured as a portion of the circumference of a circle insures a smooth and even flow of staples, accommodates a great number of staples, and yet conforms relatively closely to the configuration of the gun itself.

My stapler is compact and light and may be easily adjusted or repaired. It is extremely simple to remove jammed staples and, if necessary, the cylinder head may be quickly removed and the interior of the cylinder exposed. The groove running from the main vent to the rear of the piston is self-cleaning due to the movement of the piston over the groove.

It is to be understood that modifications may be made in my invention without departing from .the spirit thereof and I do not intend to limit myself otherwise than as pointed out in the claims which follow.

Furthermore, although I have disclosed many novel features of staple gun construction in combination with one another-for the purpose of setting forth a full and complete disclosure of an operative staple gunit should be noted that many of these features may be used independently. Thus the particular arcuate staple feed mechanism herein set forth and claimed may be used with, for example, drive mechanism other than that herein described.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a portable stapler having a staple driver operating in a slot to drive a staple positioned therein, a staple feeder comprising a staple carrying track one end of which discharges staples successively into said slot, said track conforming to a portion of the circumference of a circle, a staple arm radially projecting inwardly from said circumference and pivoted about a center located in said stapler, and means resiliently urging said radial arm around said circumferential track and forcing said staples on said track into said slot, said means comprising a member slidable in a portion of said stapler, means connecting said arm to said member, and means for sliding said member in said stapler portion whereby said arm is urged around said track.

2. In a portable stapler having a staple driver operating in a slot to drive a staple positioned therein, a staple feeder comprising a staple carrying track one end of which discharges staples successively into said slot, said track conforming to a portion of the circumference of a circle, a staple arm radially projecting inwardly from said circumference and pivoted about a center located in said stapler, and means resiliently urging said radial arm around said circumferential track and forcing said staples on said track into said slot, said means comprising a member slidable in a portion of said stapler, means connecting said arm to said member, and means for sliding said member in said stapler portion whereby said arm is urged around said track, said stapler portion comprising a cylinder, said slidable member comprising a piston, and said last mentioned means comprising a source of pneumatic pressure.

3. In a portable stapler having a staple driver operating to drive staples from the stapler, a

staple feeder for successively feeding staples into position to be driven by said staple driver, said staple feeder comprising a staple carrying track having a part which conforms to a portion of the circumference of a circle, a branched arm the ends of which are pivoted about the stapler, a staple follower attached to said arm adapted normally to ride on said track behind staples positioned thereon, a member slidable in a portion of said stapler, a looped member engaging said slidable member and pivoted to said branched arm, and resilient means normally urging said slidable member in such direction as to cause said looped member to force said branched arm to pivot about said stapler so as to maintain said staple follower in contact with the staples on said track.

4. The portable stapler of claim 3 in which said stapler portion comprises a cylinder, in which said slidable member comprises a piston, and in which said resilient means comprises a source of pneumatic pressure operatively associated with said cylinder.

5. The portable stapler of claim 4 in which there is provided means for releasing said pressure so that said arm may be pivoted in that direction opposite which it is normally forced, said track having another part which does not conform to a portion of a circle and which is so arranged that when said arm is pivoted in the said opposite direction said staple follower clears said track whereby additional staples may be placed thereon.

ALBERT G. JUILFS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 406,075 White July 2, 1889 1,106,861 Beadle Aug. 11, 1914 1,186,458 Von Vass June 6, 1916 1,939,632 Randall Dec. 12, 1933 1,980,967 Moody Nov. 13, 1934 2,172,847 Nydegger Sept. 12, 1939 2,268,102 Attula Dec. 30, 1941 2,298,123 I-Iarred Oct. 6, 1942 2,433,719 Van Sittert Dec. 30, 1947 2,482,993 Walker Sept. 27, 1949v 2,488,224 Mothorn Nov. 15, 1949

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