US2625938A - Filler feed for cigar bunch machines - Google Patents

Description

Jan- 20, 1953 J. F. HALsTEAD FILLER FEED FOR CIGAR BUNCH MACHINES 3 Sheets-Sheet l Filed Aug. 3l

Jan. 20, 1953 J. F. HALsTE-AD 2,625,938

FILLER FEED FOR CIGAR BUNCH MACHINES Filed Aug. 3l, 1944 3 Sheets-Sheet 2 FIGZ INVENTOR JOHN F. HALSTEAD BWM@ 72 74 63 ATTORNY Jan. 20, 1953 J. F. HALSTEAD 2,625,938

FILLER FEED FOR CIGAR BUNCH MACHINES Filed Aug. 3l, 1944 I5 Sheets-Sheet I5 FIC5.4

FIG. 5

f fig/G "zar s? INVENTOR JOHN F. HALSTEAD BW ATTORNEY Patented Jan. 20, 1953 FILLER FEED FOR CGAR BUNCH MACHINES `lohn F. Halstead, Brooklyn, N. Y., assigner to International Cigar Machinery Company, a corporation of New Jersey Application August 3l, 1944, Serial Nc. 552,042

10 Ciaims.

This invention relates to long filler cigar machines, more particularly to apparatus for removing leaf tobacco from a bulk supply and delivering it to the filler feed of the cigar machine. Heretofore the leaf tobacco was laid manually' in shingled relationship in the filler feed channel of the cigar machine to form a continuous layer of leaf tobacco from which bunch lengths were severed for assembly in a column from which bunch charges were separated for delivery to mechanism wherein a binder is wrapped about the bunch charge to form a bunch. Moreover the uniformity of the bunches so formed depended upon the skill of the attendant who laid the leaf tobacco in the filler feed channel.

It is one of the main objects of the invention to automatically form a layer of tobacco in the filler feed channel or other type of cigar filler feed, from which sections may be separated for the manufacture of cigar bunches. To this end the bulk supply of leaf tobacco may be supported in a revolving drum which is provided with internal cups having suction openings to which individual tobacco leaves will adhere and be carried upwardly from underneath the bulk supply of leaf tobacco and deposited upon an inclined chute extending into the drum.

Still another object is to remove tobacco leaves one by one from bulk so far as possible rather than in groups and to do this without tearing the leaves which might increase the proportion of scrap tobacco.

In this connection it should be pointed out that other types of filler feeds have been devised wherein a layer of leaf tobacco arranged transversely of the filler feed is advanced to feed its leading edge into the filler feed channel, and the portion of the tobacco layer so advanced into the filler feed channel is severed., The filler feed is then advanced a distance less than the length of the severed section and the severed edge of the layer of tobacco is fed into overlapping relationship with the previously severed section, whereupon an additional section is severed from the leading edge of the tobacco. In a similar lmanner a number of tobacco sections are assembled on the ller feed in shingled relationship to form a, continuous stream of tobacco. Due to the cutting of the layer of leaf tobacco there will be formation of scrap which may accumulate adjacent the cutter and fall into the stream of tobacco on the filler feed and impair the uniformity of bunch lengths subsequently separated from said stream. Moreover, if theA cutter should sever a tobacco leaf adjacent one of its edges, narrow ,strips of leaf tobacco, or small pieces,

may be formed which are objectionable in long filler cigars. For the above reasons any cutting of the filler before it enters the cigar machine is considered very objectionable by the cigar manufacturers. One of the main objects of this invention is to avoid all cutting of the filler and thereby eliminate this objection and at the same time provide a simplified construction. No knife or cutting operation is necessary in this construction because the full width filler leaves are aligned and shaped to fit the width of the feed belt channel.

Another important object of the invention is to align the leaf tobacco prior to delivery to the ller feed channel, so that the lengths of the leaves (which are at random in the bulk supply) will extend lengthwise when deposited in this channel. For this purpose the tobacco leaves sliding down the chute to which they are transported from the bulk supply in the drum, are delivered between members having vertical surfaces to a continuously traveling belt which is driven at the proper speed to cause the leaves to assume a position extending lengthwise ofthe direction in which the belt is traveling.

Among other objects it is intended to provide blending of various types of leaf tobacco in the cigar filler feed. Accordingly one or more auxiliary feed drums, which may be of slightly simpler construction than the main feed drum when handling Havana or similar shorter types of leaf tobacco, may be arranged to deliver the leaf tobacco upon the same traveling belt upon which the leaf tobacco is delivered from the main feed drum. In this manner the tobacco leavesare blended and aligned with each other.

Another object of the invention is to form a shingled layer of tobacco on the filler feed which is similar to that prepared manually. For this purpose the tobacco leaves are delivered endwise into a magazine to form a layer of shingled leaf tobacco therein and the shingled layers are deposited in overlapping relationship upon the filler feed.v In prior automatic filler feeds the leaf tobacco was not assembled in a shingled layer before being deposited in the filler feed channel.

If desired, the speed at which the auxiliary feed drum is driven may be changed to vary the proportion of Havana or other leaf tobacco blended with the filler tobacco delivered from the main feed drum. F'orA` this purpose the sprocket driving the chain running over a sprocket fastened on the auxiliary feed drum may be replaced Aby a sprocket of different diameter to drive the auxiliary drum at a different speed. Moreover in case only a small proportion of Havana leaf tobacco is to be blended with the main filler, scrap Havana tobacco may be placed in the auxiliary drum to be delivered to leaf tobacco fed from the main drum.

With these and other objects not specifically mentioned in view the invention consists in certain constructions and combinations hereinafter fully described and set forth in the appended claims.

In the accompanying drawings which form a part of this specification and in which like characters of reference indicate the same or like parts:

Fig. l shows a side elevation of the main feed drum D and an end elevation of auxiliary blending drum DA mounted in operative position;

Fig. 2 is a sectional end elevation taken on line 2--2 of Fig. l;

Fig. 3 is a sectional end elevation of the tobacco feed drum taken on the line 3-3 of Fig. 1;

Fig. 4 is a sectional end elevation of the tobacco feed channel; and

Fig. 5 is a partial side elevation of the same as seen from the line 5-5 of Fig. 4.

In the particular embodiment selected to illustrate the invention the automatic ller tobacco feed consists of a revolving tobacco feed drum D,

and a tobacco feed channel and conveyor F, run- C ning to a magazine (not shown) of a cigar machine cross-feed. The tobacco feed drum D (Figs. l, 2 and 3) consists of a cylindrical hollow body 3E provided in the rear wall thereof with an opening 32 (Fig. l) through which the tobacco leaves T are inserted by an attendant. The opening 32 is conically shaped to prevent tobacco leaves from falling out while the drum is revolving. The drum body 353 is also provided in its front wall 4i) with a circular opening Sli from which the escape of tobacco leaves is prevented by a conical iiange Se of a ring-shaped member 33 fastened on the front wall im. Member 38 is provided with an annular groove 42 which in conjunction with a corresponding groove M of a race Q6 and balls i8 forms a ball bearing and, since race 66 is mounted on a stationary bracket 55, provides means for supporting drum D and for allowing the latter to be rotated. The drum D is rotated by a sprocket 52' (Figs. 1 and 2) which drives a chain 5d held in an annular groove 56 of the member 38. Sprocket 52 is mounted on a shaft 58 held by a suitable bearing lug Gil (Fig. l) of bracket 50. To sprocket 52 is secured another sprocket 62 which isV driven by a chain 6 froml a sprocket 66 mounted on a .Shaft 68 extending from a Worm gear're'duotion motor unit 'de attached to a suitable platform 'It supported by rods lli held by a supporting frame T6.

Member 33 is furthermore provided with a number of equally spaced ducts 'I8 each of which has an outlet 89 in the outer face of said member and an inlet 8 2 in the rim thereof. The inlets 82 communicate with the inner ends of a series of conduits orV ducts 84 which are :fastened to the wall it of the drum 30 of 'the main feed D and communicate at their outer ends with corresponding holes Y86 in the periphery of drum Si). Within the drum 3i) are mountedV a series of conical cups which cover holes 86 vand are provided with one Yor more suitable screened openings S. YA'feed chute 92 fastened to bracket 5B extends at a suitable angle through conical flange 3S and opening 3Q into drum D. While the upper end of said feed chute almost contacts` the inner face of the cylindrical wall of the feed drum the lower end of said chute projects into the feed conveyor channel F. To the upper end of bracket 5i! is also attached a duct 94 which has a length somewhat less than half the circuniference of member 38 and is connected by a pipe S8 to a conventional source of suction such as a suction fan (not shown). The open side of duct Srl contacts the outer face 96 of member S8 so that suction is supplied to all ducts 18 of said member of which the corresponding outlets Se happen to be covered by said duct 94 (Fig. l)

The operation of the tobacco feed drum D is as follows: After a sufficient quantity of tobacco leaves T are thrown into said drum by the at tendant the drum is revolved in the direction of the arrow (Figs. 2 and 3) by the gear reduction motor unit 'l and the connecting parts described above, and the conical cups 88 plow through the mass of the tobacco leaves T tumbling in the bottom portion of said drum. While the outlets 8@ of ducts 78 are passing underneath the open side of duct 9d suction is applied to the corresponding cups and one or two tobacco leaves L will adhere to the screened openings 9S] of said cups and will be carried upward above the feed chute 92. Since the duct 94 ends at its uppermost point above chute 32, the outlets after passing this point are no longer connected with the source of suction, and the leaves drop into the chute S2. The cups 3S continue revolving with the drurn without suction until openings B again corne in contact with the lower end of the duct Si. The length of the latter is so arranged that the cups S8 are not supplied with suction when moving toward their lower most position, and not until they are slightly beyond this position, so that the leaves are not pickedfrom the bottoni of the mass of tobacco leaves but at the upper region thereof. This construction has the advantage of preventing the leaves L after they have once been picked up by the suction acting upon the screened openings S6 of cups 88 from being torn away by the shifting mass of the tobacco leaves T in the revolving drum. The cups 83 are made conical for the purpose of preventing any leaves which are not lifted out of the mass by suction from being carried upward on the cups. Therefore any leaf just hanging over said cups will slide off before reaching the feed chute. The side walls of the latter are designed in such a way as to provide a low portion i on the side wall over which the leaves are carried and a high portion EQ2 on its other side wall, thus assuring that every leaf will be stripped from its cup by engagement with portion m2 in case it continues adhering to the same after the suction is taken off. The lower ends of these sidewalls are of approximately the same height and high portion 132 is curved at its upper edge and has a vertical edge extending downwardiy to the lower end of its side wall and contacting the interior of the front wall i9 of the feed drum. Thus any leaf after it is once deposited into the feed chute 92 cannot be can ried back into drum ii. There are also provided a series of pins iil adjacent the outer edge of conical flange Se which will push any leaf into the feed chute S2 as it slides along the sidewall thereof in case it dropped off the cup too early and onto the edge of the side wall ide of feed chute 22.

In order to direct the tobacco leaves T, ospecially when there are only a few left in the drum, toward the suction cups 38, the interiorof the drum is equipped with a number of angularly mounted deflector plates 9| which prevent any leaves or mass of leaves from accumulating at the rear end of the drum and remaining out of contact with said suction cups. Thus said deflector plates 9| make it possible for the suction cups to pick up every leaf in the drum without the necessity of re-iilling said drum when thetobacco mass T reaches a low level.

As mentioned heretofore, the leaves drop into the feed chute and slide downward into the conveyor channel F. The latter consists of an endless conveyor belt |06 constantly driven in the direction of the arrow (Fig. 1) by means of a pulley |08 mounted on a shaft ||0. Said belt is led over a supporting plate I I2 and an idler pulley (not shown). Shaft ||0 is constantly driven by a pulley ||6 which in turn is driven through a belt I8 by a pulley I 20 mounted on a motor shaft |22 of a, motor |24 secured to a bed plate |26 mounted on the supporting frame 16. Shaft I|0 is supported by a pair of suitable bearing brackets |28 secured to a plate |30 held by a pair of frame brackets |32 attached to the bed plate |26 (Fig. 1). Plate |30 also supports the drum supporting bracket 50, and a pair of brackets |34. Brackets |34 carry a cross bar |38 to which the plate II2, which supports conveyor belt |06, is attached. The sides of thefeed channel F are formed by two vertical guide plates |42 and |44, each of which is held by a pair of angle plates |46 secured to cross bars |38. The conveyor channel F is furthermore provided with a, cam operated gate G (Figs. 1, 2, 4 and 5) for the purpose of preventing any leaves from dropping through the channel and onto the continuously running conveyor belt |06 thereof, whenever it is not desired to feed tobacco to the cigar machine.

' The channel gate G consists of a gate plate |48 hinged upon a horizontal rod |50 supported in lugs on the upper edge of the channel side wall |44. To the upper central portion of gate plate |48 is secured an operating lug |52 which is also pivoted to the hinge rod |50. Said lug |52 protrudes through a suitable opening or cut-out |54 in side wall |44 to the rear of the same and is connected by a link |56 to a pivot pin |58 (Figs. 1 and 2) on an arm |60 pivoted to a shaft |62 supported by a suitable bracket'l64 secured to the side of bed plate |26. The pivot pin |58 of arm |60 is connected by a link |66 to an arm |68 secured on one end of a shaft which is supported in one of the brackets k|32 and rocked by a cam-operated lever (not shown). Shaft |10 is supported by a suitable bearing lug |33 in one of the frame brackets |32. A tension spring 200 (Figs. l and 2) fastened to pivot pin |58 and anchored to frame 16 is employed to keep gate |48 in closed position i. e. in upward position, as shown in dotted lines in Fig. 4, except during that period of the cycle when shaft |10 is rocked to open the gate against the tension of spring 200.

, A stop lug 202 (Figs. l and 2) mounted on the rear side of frame 16 is provided to check the upward movement and closed positions of gate |48 by restricting the extent of downward movement of arm |60.

The continuously running conveyor belt |06 must have the proper speed to cause the leaves driven has been found to be of a magnitude which will give the leaves the necessary momentum when leaving belt |06 to cause them to slide on any smooth platform that may be provided.

As mentioned heretofore, there maybe one or more auxiliary feeds employed in addition to the main feed drum D. These auxiliary feeds are chiefly used for blending purposes, so as to add Havana tobacco leaves and/or other tobacco leaves to the main filler tobacco. The auxiliary feed drum is of smaller size and is provided with screened suction openings in its periphery instead of the cups used in the main feed drum, because the shorter lengthsof .the Havana leaves will be picked up edectively with screened suction openings. With the longer lengths of Pennsylvania leaf tobac-co used'in the main feed drum, the wrinkling thereof might interfere with the adhesion of the leaf tobacco to suction openings such as employed in the auxiliary feed drum. In Figs. 1 and 2 is illustrated an auxiliary feed DA which consists of a hollow drum 204' having a conical filling opening 206 (Fig. 2) and a conical feed or discharge opening 208 (Fig. 1). The cylindrical portion of drum 204 is provided with a number of equally spa-ced holes 2|0 (Fig. 2) each of which is covered by a hollowsuction box 2 I2 secured to a angelike extension of the front wall 2|4 of drum 204. Each suction box communicates with an opening 2|6 in the flange of front wall 2|4. Like the main feed drum D, drum 204 is provided with a stationary semicircular suction duct 2|8 having its open side contacting the flange of front wall 2| 4 of drum 204 and supplying suction to every hole 2|6 in said flange whi-ch happens to be underneath and facing the open side of the suction duct 2|8 and thereby applying suction through the boxes 2|2 to the corresponding holes 2|0. Duct 2|8fby means of a pipe 220 is connected to the semicircular suction duct 94 of the main feed drum D. The suction duct 2|8 is secured to and sup-ported by a lug 222 (Fig. l) extending from a supporting bracket 224'. To the inner face of the latter is fastened a ring 226 (Fig. l) provided with an external circumferential groove in which are mounted ball bearings (not shown), which support a race 228 attached to the front wall 2|4 of drum 204, thereby providing a revolving support for said drum. Since the support for drum 204 is similar to the support for drum 30, further description thereof is deemed unnecessary. On the periphery of the race 228 are provided sprocket teeth forming a sprocket 230 which through a chain 232 is driven from a sprocket 234 mounted on a, shaft 236 which is supported by suitable bearing lugs 238 extending from the lower portion of frame 16. On shaft 236 is mounted a bevel gear 240 which meshes with and is driven from abevel gear'242 mounted o'n shaft 68 which also drives the main feed drum D.

In order to prevent'the tobacco leaves in the auxiliary drum from being drawn into the openings 2 |0 by suction, said opening may be covered by screens. Since the auxiliary feed drum is smaller and the quantity of tobacco leaves placed in the same is much less than is used in the main feed drum', the conical suction cups 88 used in the latter are eliminated and vreplaced by the screened holes 2 I0, for it was found that it is not necessary to counteract the sliding effect of the tobacco mass when a leaf is pulled out of a comparatively small mass. Within the cylindrical body of drum 204 are also secured a number of `angularly mounted deflector plates 244 which serve the Vsame purpose as plates 9| in themain feed drum. An inclined feed chute 246, which is similar in construction and principle lto feed chute 92 of the main drum, extends into drum 204 and is supported by a bracket 248 (Fig. 2) secured to the drum supporting bracket 224. Bracket 224 is mounted on an extension 25D of plate |36. The lower end of chute 246 overlies inclined guide plate 252 which extends above the upper edge of side wall |44 of the feed conveyor F. Plate 252 is suitably secured to supporting bracket 224.

The operation of the auxiliary feed DA is the same as that of the main feed D. The tobacco leaves in drum 204 are picked up by suction supplied to the screened openings 2|!) and carried upward above the chute 246 to a point where the suction duct 2 8 terminates, and the released leaf L2 (Fig. 1) drops into the inclined feed chute 246 and slides into the conveyor channel F. It should be again emphasized that the conveyor belt |06 should have the proper speed to carry the contacting end of said leaf away quickly enough to cause said leaf to assume a position extending longitudinally of said conveyor channel. See leaw L2 within the broken away portion of channel F in Fig. l.

The cigar machine is provided with a magazine (not shown) mounted to receive the tobacco from the end of the conveyor belt |66. This magazine has a smooth bare bottom. Each leaf coming from the belt |66 will slide along the bottom, succeeding leaves sliding partly upon the preceding leaf so that the entire layer of tobacco leaves assume a somewhat shingled formation.

A predetermined quantity of tobacco leaves is deposited into the magazine, and then the feed drums are automatically stopped and further delivery of tobacco ceases. When the feed drums stop, cam-operated gate G moves to closed position to prevent any leaves from coming down the chutes 92 and/ or 246 of the drums into the channel F.

What is claimed is:

1. The combination with a hollow member adapted to support a bulk supply of tobacco leaves within its interior and be revolved whereby the interior of said member will be moved under said bulk supply of leaf tobacco, of means for revolving said member to move its interior underneath the bulk supply of tobacco, suction devices at the peripheral wall of said member to cause adhesion of a tobacco leaf to said member While it is moving under the bulk supply, and means for incapacitating said devices when the portion of said member to which a tobacco leaf allieres has moved from underneath the bulk tobacco supply, to terminate the adhesion of the tobacco to said member.

2. The combination with a hollow member adapted to support a bulk supply of leaf tobacco within its interior and be yrevolved whereby the interior of said member will be moved under said bulk tobacco supply, said member having limited areas thereon to which tobacco leaves are caused to adhere, means for revolving said member to move the interior of said member under the bulk tobacco supply, suction devices in said limited areas thereof in the wall of said member to cause the tobacco leaves to adhere to said areas while they are carried by said member under the bulk tobacco supply, and, means for terminating the suction to said devices after they have been carried away from the bulk tobacco supply.

3. The combination with a revolving Vdrum having an apertured end wall and adapted to contain va bulk supply of leaf tobacco, said drum being provided on its interior with suction means for removing tobacco leaves from the bottom of said tobacco supply and carrying the leaves to the top of said drum, of a chute extending through the aperture of said end wall sufficiently into the interior of said drum to receive tobacco leaves dropped from said suction means and deliver them outside of said drum.

4. The combination with a revoluble drum adapted to contain a bulk supply of leaf tobacco, said drum having a peripheral wall and end walls and being provided on its peripheral wall with internal perforated cups, of means for applying suction to each of said cups successively as they pass under said bulk tobacco supply to cause adhesion of a tobacco leaf to each of said cups, and terminating the suction as each cup reaches the uppermost position to permit the adhering tobacco leaf to drop off the cup.

5. The combination with a revoluble drum adapted to contain a bulk supply of leaf tobacco, said drum being provided with internal perforated cups, of means for applying suction to each of said cups successively as they pass under said bulk tobacco supply to cause adhesion of a tobacco leaf to each of said cups, and terminating the suction as each cup reaches the uppermost position to permit the adhering tobacco leaf to drop off the cup, said means including a stationary annular support, a ring fastened to one end wall of said drum and revolubly mounted on said support, said ring being provided with ports having outlets in the outer face of said ring, conduits connected to said ports and communieating with the interior of said cups, and a duct concentric with and communicating with the outlets of the ports in said ring, the upper end of said concentric duct being disposed adjacent the uppermost point of said ring and its lower end terminating at a point above the lowermost portion of said ring, said duct being connected to a source of suction and the drum revolving in the proper direction to cause to be applied to each cup successively while it is moving upwardly under the bottom of said bulk tobacco supply and thereby cause adhesion of a tobacco leaf to each cup while it is moving upwardly from the bottom of the bulk supply Vand thereby carry the adhering tobacco leaves to the uppermost portion of said drum where the suction is interrupted on each cup successively.

6. The combination with a revoluble drum adapted -to contain a bulk supply of leaf tobacco, said drum being provided with internal perforated cups, of means for applying suction to each of said cups successively as they pass under said bulk tobacco supply to cause adhesion of a tobacco leaf to each of said cups, and terminating the suction as each cup reaches the uppermost positionV to permit the adhering tobacco leaf to drop off the cup, said cups being arranged adjacent one end of said drum, and a series of deflector plates mounted on the interior of said drum adjacent the other end thereof and arranged to displace the mass of tobacco leaves toward said cups.

'7. The combination with a revoluble drum having a peripheral wall and end walls and adapted to contain a bulk supply of leaf tobacco, said drum being provided in its periphery with suction devices, of means for applying suction to'each of said suction devices successively as they move upwardly under said bulk tobacco Supply to cause adhesion of a tobacco leaf to each of said suction devices, and discontinuing the suction on each device as it reaches its uppermost position to permit the adhering tobacco leaf to drop off.

8. The combination with a revolving drum having an apertured end wall and adapted to contain a bulk supply of leaf tobacco, said drum being provided on its interior with suction means for removing tobacco leaves from the bottom of said tobacco supply and carrying the leaves to the top of said drum, of a chute extending through the aperture of said end wall suiciently into the interior of said drum to receive tobacco leaves dropped from said suction means and deliver them outside of said drum, a stationary annular support, and a ring fastened to one end Wall of said drum and surrounding said chute and revolubly mounted on said support, said ring being provided with pins on its inner face adapted to engage tobacco leaves hanging over one edge of said chute and carry them into said chute.

9. The combination with a revolving drum having an apertured end wall and adapted to contain a bulk supply of leaf tobacco, said drum being provided on its interior with suction means for removing tobacco leaves from the bottom of said tobacco supply and carrying the leaves to the top of said drum, of a chute extending through the aperture of said end wall sufciently into the interior of said drum to receive tobacco leaves dropped from said suction means and deliver them outside of said drum, said chute having upwardly extending side walls which project into the interior of the drum, whereby the leaves are carried over one of said side walls by said suction means and released to drop into the chute and slide down between the side walls thereof, the upper edge of the side wall over which the tobacco leaf is carried by said suction means lying below the lower end of the tobacco carried thereover by said means.

10. The combination with a revolving drum having an apertured end wall and adapted to contain a bulk supply of leaf tobacco, said drum being provided on its interior with suction means for removing tobacco leaves from the bottom of said tobacco supply and carrying the leaves to the top of said drum, of a chute extending through the aperture of said end wall suiciently into the interior of said drum to receive tobacco leaves dropped from said suction means and deliver them-outside of said drum, said chute having upwardly extending side Walls which project into the interior of the drum, whereby the leaves are carried over one of said side walls by said suction means and released to drop into the chute and slide down between the side walls thereof, the upper edge of the side wall over which the tobacco leaf is carried by said suction means lying below the lower end of the tobacco carried thereover by said means, and the other side wall of said chute being high enough to engage and remove a tobacco leaf from said suction means if it continues adhering to said means after being carried to its uppermost position.

JOI-IN F. HALSTEAD.

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

UNITED STATES PATENTS Number Name Date 78,117 Morrison May 5, 1868 244,748 Hammerstein July 26, 1881 387,098 Montgomery July 31. 1888 512,150 Briggs Jan. 2, 1894 1,328,735 Harriss Jan. 20, 1920 1,331,235 Bristow Feb. 17, 1920 1,364,222 Vaudreuil Jan. 4, 1921 1,536,216 Heyman May 5, 1925 1,561,856 Heyman Nov. 17, 1925 1,582,544 Rundell Apr. 27, 1926 1,740,571 Bronander Dec. 24, 1929 1,754,117 Pacini Apr. 8, 1930 1,864,728 Hawkins et al June 28, 1932 1,977,994 Lindblad Oct. 23, 1934 2,018,918 Lorentz Oct. 29, 1935 2,192,518 Eissmann Mar. 5, 1940 2,226,370 Carlson Dec. 24, 1940 2,255,054 Halstead Sept. 9, 1941 2,276,361 Wheeler Mar. 17, 1942 2,284,472 Halstead May 26, 1942 2,306,380 Durning Dec. 29, 1942 2,311,373 Durning Feb. 16, 1943 2,329,183 Burns Sept. 14, 1943 2,339,563 Giles Jan. 18, 1944 2,340,814 Whitaker Feb. 8, 1944 2,357,860 Whitaker Sept. l2, 1944 2,378,953 Rundell June 26, 1945 FOREIGN PATENTS Number Country Date 180,588 Germany Jan. 28, 1907 331,616 Great Britain July 10, 1930 495,614 Germany Apr. 9, 1930 673,308 Germany Mar. 20, 1939

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