US2501564A

US2501564A - Staple feed for fastener applying machines

Info

Publication number: US2501564A
Application number: US634441A
Authority: US
Inventors: Charles B Goodstein
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-12-12
Filing date: 1945-12-12
Publication date: 1950-03-21
Anticipated expiration: 1967-03-21

Description

March 21, 1950 c. s. GooDsTElN 2,501,564

STAPLE FEED FOR FASTENER APPLYING MACHINES Filed Deo. 12, 1945 4 Sheets-Sheet l Fig. B

ATTORNEY March 2l, 1950 c. B. lcaool: s'rr= u\| 2,501,564

STAPLE FEED FOR FASTENER APPLYING MACHINES Filed D90. l2, 1945 4 Sheets-Sheet 2 INVENTOR C/mr/g Goods-fein ATTORNEY March 21, 1950 C. GOODSTEIN STAPLE FEED FOR APPLYING MACHINES 4 sheets-sheet 4 Filed DeC. 12, 1945 INVENTOR Char/e5 Gooaszefn ATTORNEY Patented Mar. 21, 1950 U Nl if ED" S TAT ES TNT OFFICE STAPLE FEED FOR FASTENER APPLYING MACHNES Charles B. Goodstein, New Rochelle, N. Y.

Application December 12, 1945, Serial No. 634,441

Another object of thisinvention is to providel a stapling deviceof the character described, in which the drawer may be wholly drawn out of the tubular casing when it is desired to rell the drawer with staples.

Another object oi this invention is to provide a stapling machine of the character described, in which the casing is transparent and the pusher is colored or opaque wherebyto visually indicate quantity of staplesiny the device.

Still a further object ofv this invention is to provide in a stapling machine of thecharacter described, a' casing formed with a longitudinal l event that a staple gets stuck, and also to permit easy cleaning and to provide for complete visibility.

Still a further object of this invention is to provide a stapling device of the character described, comprising a staple magazine and a driver holder pivoted to the magazine, and comprisin'I a pair of side members interconnected at their forward edges by ahead or button carrying a driver or plunger whereby to expose the top oi the tubular drawer casing.

Ye., another object of this invention is to provide a strong, rugged and durable stapling machine of the character described, which shall be relatively inexpensive to manufacture, easy to manipulate', and yet practical and eiiicient to a high degree in use.

Other objects cf'this invention will. in part be obvious and in part'hereinafter pointed out.

The invention accordingly consists in the features of construction, combinations of elements, and arrangement of parts'which-will be exemplified in the construction: hereinafter described, and of which the scope ofi application will be indicated in the following claims.

Inv the; accompanying drawing, in, which is 55v 5 Claims. (C1. 1 3) shown one of the various possible illustrative embodiments of thisinvention,

Fig. l is a top plan view of a stapling device embodying the invention;

Fig. 2 is a cross-sectional view taken on line Zi- 2 of Fig. l; l

Fig. 3 is a cross-sectional View taken on line 3-3` of Fig. 2;

Fig. 4' is a cross-sectional viewtaken on line ll-il' of Fig. 2;

Fig. 5 is a front' endv view of the stapling device;

Fig. 6 is a perspectiveY view of the tubular casing;

Fig. '7 isa perspective View of a drawer with the pusher therein;

Fig. 8 is a view similar to Fig. 2, but with the drawer partly pulled out to permit insertion of a-new staple strip;

Fig. 9 is a side elevationalview of a stapling device embodying theinvention and illustrating a modified construction;

Fig. 10 is a longitudinal cross-sectional view thereof;

Fig. 11 is a cross-sectionalview taken on line ll-l lof Fig. 10;

Fig. 12 is a cross-sectional view taken on line l2'-l2 of Fig. 10;

Fig. 13 is a side elevational view of a stapling device embodying another modified form of the invention;

Fig. 14 is a topplan view of the structure shown in Fig. 13;

Fig. 15 is a cross-sectionaliview taken on line l--liof Fig. 14;

Fig. 16 is a cross-sectional view taken on line ifi-leef Fig. 15.

Fig. 17 is a perspective View of: the pusher used in the staplingdevice shown in Fig.` 13;

Fig. 18 isa perspective view of the front end plate for the staple drawer employed in the stapling device shown in Fig. L3; and

Fig. 19.'is a partial elevational detail View of a front endof the staple drawer as shown in Fig. 15.

Referring now in.. detail to the drawings, l0 designates a staplingi. device embodying the invention. The same comprises generally, a base il, a staple: magazine laf-pivoted thereto, and a driver holder I3 likewise pivoted` to the base for pivotalmovement relative to the magazine.

The base ll comprises: a Iiiat substantially reck tangular member l5', having its-iront, rear, and side edges bent downwardly for contacting a sup.- porting surface. At the.: front end of`member |`5 is an opening i6. At its rear end, member l5 is formed with a pair of parallel longitudinal eX- tending slots l1. Attached to the underside of member l5 is an anvil I8 of any suitable type, for either spreading or bending the staple legs or for both.

Attached to the rear end of member |5 is a U-shaped member 23. Member 20 comprises a bottom portion 2|, and upstanding legs 22 passing through the slots |1.

The bottom portion 2| may be spot welded, riveted, or otherwise fixed to the base member I5. The arms or ears 22 are formed with horizontally aligned openings through which there extends a pivot pin 24. The pivot pin 24 may be riveted or headed at its opposite ends, as at 25.

Riveted to the upper side of the base plate |5, as by rivet 21, is a leaf spring 28 adapted to engage the underside of staple magazine I2 for keeping it normally somewhat raised above the base.

Staple magazine l2 comprises a tubular casing 30, having a bottom wall 3|, a top wall 32, and side walls 33. The side walls 33 have aligned openings 33a at their rear ends through which the pivot pin 24 extends. The top wall 32 is formed with a longitudinal slot 35 terminating short of the ends of said top wall. The tube 33 may be open at both ends. The bottom wall 3|] is formed adjacent its front edge 35 with a transverse slot 31 through which a staple may be driven against the anvil |8.

The top wall 32 is formed with a transverse slot 39 similar to and aligned with the slot 31. Front edge 3B of the bottom wail 3|' extends beyond the front edge 43 of the top wall 32, as clearly shown in Fig. 6 of the drawing. Said side walls 33 are formed, adjacent their forward ends with notches 42 and upstanding lips 43 disposed forwardly of said notches.

Slidably mounted within the tubular casing 33 is a staple drawer 45. Said drawer comprises a bottom wall 45 and side walls 41. The bottom wall 45 slidably contacts the upper surface of bottom wall 3|. The side walls 41 slidably contact the inner surface of side walls 33. The upper edges of side walls 41 substantially contact the underside of top wall 32. The bottom wall 4B is formed with an upstanding lip 50 at its forward edge. Lip 5|) is of less width than the bottom wall 45, and is spaced rearwardly of the front end of side walls 41. Lip 5|! may be formed by slitting the bottom wall from the front end and pressing the metal upwardly. The distance between the side edges 5| of lip 5|! and the inner surface of side walls 41 should be more than the spaces necessary to permit staple legs to pass through said spaces.

It will now be understood that side walls 41 extend beyond lip 50'. Extending portions 53 are formed with aligned vertical slots 54 for the purpose hereinafter appearing.

The lower ends of slots 54 register with notches 42. The upper ends of slots 54 extend above the lips 43. At the rear end of bottom wall 4E are a pair of upwardly extending short lugs 55 adjacent the side walls of the drawer, for the purpose hereinafter appearing.

Disposed between the forward ends 53 of side walls 41 and fixed thereto, is a U-shaped member 33, having a bottom wall 5| and upstanding side walls 62. Side walls 62 contact the inner surfaces of the front ends 53 of side walls 41 and may be spot welded thereto. The bottom wall 6| is in the plane of the bottom wall 46. Memvand pivot pin 24 is a pusher spring 81.

ber B0 is spaced from lip 50 by a distance sufcient to permit a staple to pass between said member 60 and said lip 5U thereby forming between the lip 5i! and the bottom wall 6| a slot 64 which, in the operative position of the stapler, registers with slot 31. Walls |52 are formed with slots 53 registering with slotsv 54.

Means is provided to retain the drawer 45 in operative condition within the tubular casing 33. To this end there extends through the registering

slots

54, 63, a pin 1|) having enlarged heads 1| at its ends. When the stapler is in operative position, pin 1|! rests in notches 42.

Attached to the upper surface of bottom wall 6|, is a leaf spring 13 which engages pin 'i9 to retain said pin within said notches 42. To release the drawer and permit the latter to be slidably moved forwardly, it is only necessary to lift pin 10 to clear the projections or lips 43, and then the drawer may be slidably moved forwardly.

Within the drawer is a staple strip comprising U-shaped staples. The staples are of such size that they will ilt into the drawer and will be supported therein without any additional guides. The staples have downwardly extending arms, as shown in the drawing. It will be noted that the foremost staple will straddle lip 5|). For this reason the upper edge 50a of said lip is somewhat below the level of the upper edges of side walls 41.

Means is provided to press the staple strip 80 forwardly into engagement with the rear edges 62o', of side walls 52. To this end there is slidably mounted within the drawer, a pusher 82. The pusher 82 comprises a block of substantially rectangular cross section slidably fitting within the drawer. The height of block 32 is substantially equal to the height of the drawer. Said block is formed in its front face with a groove 83 adapted to receive the lip 50 when there are no more staples in the drawer. Screwed into the upper surface of the block is a pin or screw 84. The screw 84 passes through the slot 35. It is formed with a head 85 disposed above the top wall 32.

Within the drawer, and between the block 82 The pusher spring is so shaped as to fit within the drawer without any additional guides, thereby eliminating the necessity for a central guide rod. The spring 31 is of the coiled type and is preferably curved so that the lugs 55 of the drawer may move forwardly past the spring when the drawer is pulled out of the casing 3|). The lugs 55 will contact the block to limit forward movement of the drawer. Movement of the block is limited in a forward direction by Contact of the pin 84 with the forward end of the slot 35.

It will now be understood that the drawer may be pulled forwardly and the staple strip dropped into the drawer and the drawer then pushed back into the casing.

The tube and drawer may be made of transparent material and the pusher 82 of colored or opaque material, so that a person can see at any time the position of the block and determine what amount of staples are left therein. The amount of staples may also be noted by the position of the head 85 of screw 84. When the head is at the forward end of the slot 35 the machine will be in condition for relling.

The plunger holder I3 comprises a pair of parallel side bars 90, formed with openings at its rear end through which the pivot pin 24 passes. The side bars are interconnected by a top button I9.2'. The button 92 has a top wall. 93: and side; walls 94, and a frontrwall 95.V The side walls may be` spot welded or otherwise attached to the side bars.

Attached tothe inner surface of the front wall.

95' by a rivet or in any other suitable manner;` is a. downwardly extending driver or plunger k|31. The plunger is disposed above the slot 39 so that when the holder is pressed downwardly, the plunger willY press a staple downwardly through the

slots

64 and 31 against the anvil. The sidev walls 9d are formed with inwardlyY turned ngers 98. Attached to the top wall 32 is a spring 99.

The spring 99 has spaced' arms 99a which are riveted or otherwise fixed to. the top wall as at Hill.

The arms 99d are spaced so that the slot 35 and the pin head 85 may be seen. The freeA end of the spring 99 engages between the lingers 98. and. the top wall 93. The spring thus servestwo purposes. It lifts the driver holder after theholder has been depressed and released, and it alsov prevents lifting the driver holder more than a predetermined extent. If desired the means for lifting the driver holder may comprise ngers |32 on the side bars 9d adapted to engage the underside ofthe casing 35.

In Figs. 9 to l2. thereis shown a stapler ita embodying a modi-ned form. of the invention. The staplerV lcz comprises a base ||9 providedv at its rear end with a pair of upwardly'extending aperturedy ears i|2 carrying a. horizontal transverse pivot pinv l ifi. Pivoted onsaid pivot pin is a staple magazine H5. Said staple magazine 5 cornprises a member ile having a top portion ||1 and downwardly extending ears formed with through openings throughv which the pivot pin i3 extends. Welded or otherwise attached to member Ht is a holder |29 comprising a top wall |2| having downwardly andi inwardly extending side guide flanges |22 providing a pair of spaced aligned guide channels 23.

The holder |29' is open at its forward end. as; shown in the drawing. Slidably mounted on the holder is a drawer |39'. Drawer |39 is open at. the top. It has a bottom wall |3l', upwardly extending side walls. |32, and outwardly extending top flanges |33 received within the slots |23. The side walls |32 of the drawer are formed with inwardly extending portions |35 at the front end of the drawer, to form a front wall for the drawer. Extending from the wall portions |35 'are forwardly extending mutually contacting tabs |35 which may be riveted together at |31 thereby forming a pull finger for pulling out the drawer as will appear hereinafter. The bottom wall itl of the drawer is formed with a transverse slot |39 just inside of the walls |95. Said bottom wall |3| is also provided with an upwardly extending finger |40 parallel to walls |35 and spaced therefrom by little more than the thickness of a staple.

The opstanding lip or nger |46 is of less .vidth than the drawer so that the side edges thereof are spaced from the inner surfacesv of the side walls of the drawer by somewhat more than the thickness of a staple. Within they 16 At the front end of opening |82 is a front wall' drawer is': a. stapley strip |42, adapted to straddle the lip M0. |35 and may be driven downwardly through the slot |39. as will appear hereinafter.

Within. the drawer is a staple pusher |59 adaptedl to push against the staple strip. rIhe pusher comprises a generally prismatic block and is formed with a. groove |5i| at its forward surface adapted tol receive the lip |40. Screwed to the. upperv side of the-pusher |59 is a screw |53 passing. through the slot |24 and having a head disposed at the upper side of the holder. Pusher |56 is formed with a, longitudinal throughopening tla. |-5|`h. Attached to pivot pin ||3a is a rod |5|c passing through opening |5|a. tween the pusher |50- and pivot pin |305 and received on rod I'5|c'is a coil spring |55 adapted: to press the pusherl |50 forwardly. The forward end of spring |55V is received on collar |5|b.

Means is provided' to drive staples from the magazine H5; To this end there is pivoted on the pivot H3 a driving member |69. Said driving member comprises a pair of spaced side bars ||5-| formed with openings at their rear ends receiving the pivot pin ||3` therethrough. Interconnecting the forward ends of the boards IBI is a knob or button |62. The button |52 has a front downwardly extending wallv |53. Fixed thereto extending downwardly therefrom is a drive-r or plunger |554v adapted to drive the lead-ing staple throughy the slot |39. The top wall of the holder is cut away at its forward edge to receive the plunger. The plunger enters the drawer between wall- |35 and lip |40. Attached to the top of thev holder is a strip spring |66 en gaging at its free upper end, a loop |61 on the button |52. The spring |56' raises the driver after the-staple is driven.

The base Hill may be provided with a suitable anvil ||9a for turning the legs of the staple. Interposed between the base of the staple magazine is a spring |10 to space the magazine somewhat above the base. O-ne side ange |33 of the drawer is formed adjacent its forward and rear ends with notches |15, |16. When the drawer is in position for use within the holder, the spring n'ger |28 engages notch |15 to retain the drawer within the holder. When it is desired to withdraw the holder to place more staples therein, the spring latch |21 is retracted, and the drawer is pulled out. The spring finger |26 then snaps into notch |16 to keep the drawer from coming entirely out of the holder. A new staple strip may then be inserted into the drawer. Thereafter the latch is again retracted and the drawer pushed back into the holder until the spring again snaps into notch |15.

In Figs. 13 to 19 there is shown a stapling device 9b embodyingA the invention and illustrating another modied form thereof. The stapling device ||lb comprises a base |1519 provided with a usual anvil |15`a. At the rear end of the base are a pair of upstanding apertured ears 15a supporting a transverse pivot |11. Hinged on the pivot |11 is a member |18' which may be made of synthetic plastic material or any other suitable material. Member |18 is formed with an apertured pair of ears |19 through which the pivot pin |11 passes. Said member furthermore comprises a straight elongated portion |30 formed with a longitudinal substantially cylindrical passage |82 terminating short of the front end, but extending to the rear end of said portion |80.

The leading staple contacts wallsl Itis also formed with a collarl Interposed be- 183. Member 180 is also formed with a vertical slot |84 coextensive and communicating with opening |32. Slot |84 extends downwardly to an undersurface |86 of said portion 180. The rear end of opening 182 is screw threaded as at |81. The slot 1811 likewise extends to the rear end of member |18. Portion 190 is also formed with opposite horizontal slots |89 providing inwardly turned iianges spaced beneath the undersurface |82. The inner edges of the flanges |90 are spaced from one another as shown in Fig. 16 of the drawing.

The rear end of opening |82 may be closed by a screw plug |92 as shown in Fig. 15.

One side edge |93 of portion 180 is formed with a through slot |95 communicating with groove |89 for the purpose hereinafter appearing. Attached to said side edge |93` as by screw or rivet 196, or in any other suitable manner, is a spring latch 191 formed with a finger 198 extending through the opening |95. The spring latch |91 is provided with a knob or handle |99 for the purpose hereinafter appearing.

Slidably mounted on portion |80 of member |13 is a drawer 200. The drawer 200 may be made of sheet metal, synthetic plastic or other suitable material. tom portion of inverted V-cross section. Por-- tion 20| thus comprises downwardly and outwardly inclined walls 202. Extending upwardly from the lower ends of the walls 202 are vertical walls 203. Extending outwardly from the upper ends of walls 203 are horizontal aligned flanges 204. Flanges 204 are slidably received in the grooves 189. The side walls 203 extend somewhat beyond the forward end edges 205 of walls 202 as shown in Fig. l0. Welded or otherwise attached"to the front edges 20B of said side walls is a front plate 201. Plate 201 extends up above the upper surface of the drawer 20|) as at 208. It will now be understood that plate 201 is spaced from edges 205. This space should preferably be sufficiently wide to permit passage of staple 2|0 driven downwardly through slot 211 formed at the bottom of said space. of portions 212 forming the junction between

walls

202 and 239, are beveled downwardly and forwardly as at 213 for the purpose hereinafter appearing.

Furthermore, the inner surface ci plate 201 is formed with a pair of spaced, similar curved grooves 211| in alignment with the edges 2 3. The purpose of grooves 2|3 and 2M is that if a staple has its legs bent, the inclination of said surfaces will bring the legs of the staple down to slot 2| 1, as will be more fully explained hereinafter.

The flange 201| of member 220 which is adjacent edge |93 o member |18, is formed adjacent its forward rear ends with

notches

216 and 211, respectively. When the stapler is in use, spring iinger |95 engages within notch ZIE to keep the drawer from sliding forwardly. However, spring latch |91 may be retracted to permit the drawer to be slidably moved forwardly until the spring ringer snaps into the notch 2| 1 to prevent the drawer from being pulled out altogether.

Mounted within drawer 200 is a strip of staples 2|0. The staples have crown portions at the top and downwardly extending legs. The legs lie adjacent the inner surfaces of walls 203. The

The same comprises a bot' The forward edges all) d lower ends of the legs of the staples are located above portions 212 of the housing.

Means is provided to push the staple strip toward end wall 201. To this end there is slidably mounted within the drawer and member 118, a pusher 22d. The pusher 220 comprises a flat horizontal portion 22| from which there extends downwardly longitudinal side flanges or legs 222. The legs 222 lie in the plane of the legs of the staples 210. The top wall 22| lies in the plane of the crown portion of the staples 210. The flanges 222 project forwardly somewhat beyond the top wall 22|. The upper ends 223 of the front edges 224 of said flanges 222 are beveled upwardly and rearwardly for the purpose hereinafter appearing. Extending upwardly from the top wall 22| is a longitudinal central web 225 which passes through slot 18d of member |18. Integrally formed with the web 225 is a horizontal cup or tube 220 closed at its front end by wall 221. The tube 226 is slidable longitudinally in the cylindrical opening |82. Interposed between the plug |92 and the back wall 221 of the tube 22S and extending through passage 182 is a coil compression spring 221 which urges the pusher 220 rearwardly for pressing the staples against the inner surface of the forward end wall 201.

Means is provided to drive the staples one at a time through the slot 21|. To this end there is pivoted on the pivot |11, driving member 230. The driving member 230 comprises a pair of parallel side bars 23| formed with openings through which the pivot |11 passes. Said side bars 23| are normally inclined upwardly and forwardly. They are interconnected at their forward ends by a top knob 232 attached to said bars in any suitable manner. The knob 232 is formed at its front end with a downwardly extending iiange 233. Attached to ywall 233 as by rivet 23d, or in any other suitable manner, is a downwardly extending plunger 235 which contacts the inner surface of wall 201. Attached to the top of member |18 is a strip spring 238, which engages lugs 239 on the knob 230. The spring 238 normally raises the driver to the position shown in Fig. l5. In said position the lower end of plunger 235 is above the staples. As the knob 232 is depressed the plunger will force a staple downwardly through the space between edge 205 and the inner surface 20S and downwardly through slot 2| 1. When there are no more staples in the drawer, the edges 224 of pusher 220 will contact the inner surface of plate 201. After the driver is depressed, the plunger blade 225 will engage the beveled surface 223 to somewhat retract the pusher.

Sometimes the staple legs are pushed forwardly or rearwardly and it will be understood that the beveled or curved edges 213, 2M will guide the legs to the slot 211.

A spring 221i be attached to the base as shown in Fig. 15. Said spring engages the underside of the drawer to normally maintain the staple magazine in horizontal position.

It will now be understood that when the drawer is depleted of staples, the knob |99 may be pulled back and the drawer can then be pulled forwardly. The pusher will contact wall |83 to limit forward movement of said pusher. A new staple strip may be inserted into the drawer. The drawer is then pushed back and the spring latch snaps into notch 216 to retain the drawer in p0- sition for use.

It will thus be seen that there is provided a device in which the several objects of this invention 9 are achieved, and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

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

1. A staple magazine comprising a tubular casing, a drawer within said casing, releasable means to retain the drawer in a predetermined position within said casing, said drawer being adapted to receive a staple strip, said drawer and casing having registering slots through which a staple may be driven from the magazine, a pusher slidably mounted within said drawer for pressing the staple strip in one direction, and spring means within said drawer for pressing said pusher means on said drawer to limit the movement of the staple strip in one direction, said casing being formed with a longitudinal slot, and means on said pusher extending through said slot.

2. A staple magazine comprising a tubular casing, a drawer within said casing, releasable means to retain the drawer in a predetermined position within said casing, said drawer being adapted to receive a staple strip, said drawer and casing having registering slots through which a staple may be driven from the magazine, a pusher slidably mounted within said drawer for pressing the staple strip in one direction, and spring means within said drawer for pressing said pusher, means on said drawer to limit the movement of the staple strip in one direction, said casing being formed with a longitudinal slot, and means on said pusher extending through said slot, said casing having a wall formed with a slot adapted to receive a driver.

3. In a stapling device, a staple magazine comprising a tubular casing, having a bottom wall,

side walls, and a top wall, a drawer within said t casing having a bottom wall contacting the bottom wall of the casing, and side walls contacting the side walls of said casing, and releasable means to retain a drawer within said casing, said drawer being adapted to receive a staple strip, a l

pusher slidably mounted within said drawer, and

a spring within said drawer resting on the bottom of the drawer and adapted to press against said pusher, the top wall of the casing being formed with a longitudinal slot, and a pin on saidppusher projecting through said slot.

4:: In a stapling device, a staple magazine comprising a tubular casing, having a bottom Wall, sidefwalls, and a top wall, a drawer within said casing having a bottom wall contacting the bottom-y wall of the casing, and side walls contacting thefside walls of said casing, and releasable means to retain a drawer within said casing, said drawer being adapted to receive a staple strip, the bottom-l Wall of the drawer and the bottom Wall of thel casing being formed with registering slots through which a staple may be driven, the top wall of the casing being formed with a slot disposed above the slots in said bottom walls adapted vto receive a driver.

5. In a stapling device, a member immovable *inv a longitudinal direction and formed with a pair of aligned grooves, a drawer slidably mounted on said member and provided with flanges slidavble longitudinally in said grooves, said drawer be- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 267,283 Toulmin Nov. 7, 1882 2,117,743 Polzer May 17, 1938 2,117,744 Polzer May 17, 1938 2,150,332 Maynard Mar. 14, 1939 2,240,911 Polzer May 6, 1941 2,251,833 Polzer Aug. 5, 194'1 2,288,500 Vogel June 30, 1942 ,2,309,763 Goodstein Feb. 2, 1943 2,309,779 Maynard Feb. 2, 1943 2,340,717 Vogel Feb. 1, 1944 2,345,267 Keil Mar. 28, 1944 2,346,262 Lancaster Apr. 11, 1944 2,358,317 Crosby Sept. 19, 1944 FOREIGN PATENTS Number Country Date 216,174 Switzerland Nov. 17, 1941