US2493205A - Portable electric flashlight - Google Patents

Description

Jan. 3, 1950 B. F. MULDooN 2,493,205

PORTA'BIE ELECTRIC FLASHLIGHT 11 ATTCRN EY Jan. 3, 1950 B. F. MuLDooN 2,493,205

A PORTABLE ELECTRIC FLASHLIGHT Filed Sept. 21, 1943 2 Sheets-Sheet 2 INVENTOR 15m/vn@ @ww/5" /Wuwocw i l 1 W 'l O 2 ATT N EY Patented Jan. 3, 195@ PORTABLE ELECTRIC FLASHLIGHT Berna-rd Francis MuldoonpCaldwelLNf. J=-., as-

signor to Henry Hyman, New York, N. Y.

Application September 21, 1'943', Serial'No': 503:18'2

19 Claims.

Another.' object. of. the inventionis to provide a ii'ashlight of the character' describedlwhichshall comprise relatively: few and'. simple parts and be highly efficient in use.

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

The invention accordingly consists inthe featuresI of constructiom combinations of. elements, and arrangement of parts Which willl be exempliedin the'construction hereinafter described, and: of Which-.thescopeoizapplication will be indicated in the claims.

Certain featuresv showni and/or describedy and not claimed` hereinl are shown, described and claimed in my eopending applications Serial No. 371983,. led February 8,. 1941',v and Serial No. 503,183, led September 211,. 1943;. now respectivelyy Patent No. 2,401,366 dated June 4p 1946, and Patent Non 2,358,820 dated September 26, 1944.

In the accornpanyingV drawings,l in which is shown one of= the-various possible embodiments of this inventiong.

Fig. 1: is a2 sidef elevational. View of `affiashlight embodying mynvention.;v

Fig. 2: isi a longitudinal sectional View theref through taken substantially' alongI the line 2--2 of Fig. 1;

Fig. 3 is: a longitudinall sectional View therethrough taken substantially along the line 3--3 of Fig. 2;

Figs. 4 andy 5 are sectional. views taken, respectively, substantially along the lines 4--4 and 5--5 of Fig. 3' beingV detail viewsA of. thehead and rear assembly respectively;Y

Fig. 6 is a. front to` back.. sectional exploded View ofthe flashlight; andy Figs. 7 and 8 are sectionalv viewstaken, respectively, substantially alongthe lines 1--1 and i--B of Fig. 6.

Referring now indetail to the drawings, the angle head ashlight it" embodying my invention there shown, comprises-in generalv a battery casing i2, a head assembly it, abase assembly i6 an electrical system Whic'l'includes a switch and various parts of. the. head and base assembly.

The battery ceasingJ The battery. casing I2., which is fabricated from a moldable insulating. materiall such, for

example, as phenol condensate or cellulose acetate butyrate.. comprises a. body portion. 2U which is integrally connectedl tol a'. head1 portion22. The body'portion consists of. ai hollow cylindrical. tube having' ani open. bottoni; end. which is provided with male threads 23 totl receive the. base. portion.. immediately above the threads the. body por.- tion` is provided with a circumferential. reinforcing bead 24; Near-theftopendot the casingI a similar beadA 2e is p'rcwifdeditoy impart a. balanced appearance tol the casing. Intermediate these two. beads; the exterior surface of the casing has a plurality of longitudinally extending'. ridges 28 molded therein` to rigidity thecasing' thus imparting: a high. degree off strength theretov while stillI keeping the casing'. Wall's as4 thiny as possible iii-1 order to" minimize the Weight of'. thev liashlight and maire for economy in manufacture..

rihe head. 2% of. the` casing comprises al cylindrical tube=of| the'same diameter'as the bodyportion 2u andv integrally molded therew-ith,. the line of: juncture betweenl the head and` body portions being. rounded: oft at the back 30 of the head.

The frontend1 of the: cylindrical tube comprising, the head portion'ha-saset ofv male.' threads 32 formed therein for the liead assembly M.

Although disposed inside' ofthe flashlight cas'- ingl2., the lower wall 3!!A ofthe tube forming the head. 22V is left substantially intact (Fig. 2), integrally connecting.- one' side of the' body casing portion 2li with the diametrica'll-y opposedside thereof'. Thisflower wall Sil forms a substantially arcuate; upwardly' concave integral partition betweenithe headAY and body/portions` of thefcasing and alfords substantial reinforcement t'o these parts thereof, thus increasingl the resistance of the casingA to' impact. andA rendering same less liabley to deformation.l at high temperatures and under moist o'r dry atmospheric conditions.

The interior ofi the'casing. I2'Y isof specialconfigurationto accommode'te'v the parts of the electrical: system Without' materiallyv a'ecting the strength or ruggedness of thefcasing` In the body portion a pair of longitudinal parallel spaced ribs; 3B; is' provided which between them delinea cha-nnel138 narrowingslightly near theI upper endA ot the body portion 2G. It willbe notedli that th'e rib's'run `beneath and alongside of the switch: i8 thus reinforcing the casing. where it'- is apertur'ed andco'untelsunk' to accommodate .thel switch-l The upper endf of the" channel 38 eiten'ds through.- anl openingl0 provided in the s'erni'- cy-lindricalrinner wall 34 ot the' head. Directly above/this openinglandfabo've' -thel'endofitliepliarifvnel 38a smallftaperedpin Vi2 extends integrally stops short of the tip of the pin so as to provide a slot 46 whose walls are spaced radially of the longitudinal axis of the head portion and which faces toward the front of said portion. The front end of the head portion on which the male threads 32 are molded is of greater internal diameter than the back portion thereof which is integrally formed with the body 20.

The front and back portions of the head are joined by a flaring llet 48. The high point of this fillet is so situated as to interpose a xed obstacle between the inner wall 46a of the slot 46 and the forward inner edge 41 of the head portion 22. The purpose of this construction will be later explained in connection with the electrical system.

To facilitate molding of the casing in one piece, the semi-cylindrical reinforcing wall 34 may be cut out to provide another opening 50 to receive an abutting portion of the molding cores for the head and body. This opening 50 may. as indicated, be located at the back of the head portion. 1t is reinforced by a raised wall 52 which extends from side to side of the semi-cylindrical wall 34. In addition to reinforcing the semi-cylindrical wall and the casing in general, said wall coacts in a manner later described with an element of the electrical system.

It is preferable to also reinforce the ends of the wall and this is accomplished by molding a pair of wings 54 between said walls and the adjacent parts of the head and body portions. Said wings are adapted to prevent rearward or forward deection or deformation of the wall 52.

To expedite support of the flashlight casing, a conventional metallic spring hanger 56 is provided, the same being secured to the flashlight casing by a pair of rivets 58 whose shanks pass through apertures in the belt hanger and in the back wall of the body portion where the inner ends are spun over against a steel strip 60 inside of the casing. It will be noticed that in this region of the casing the same is provided on the exterior and interior with a wide ridge 28 and a flat 62, respectively, so that the casing is appreciably locally thickened to better resist deforming stresses.

Finally the casing also has a plurality of apertures and depressions formed therein, which will hereinafter be described in detail, to position and hold various elements of the electrical system.

Disposed within the casing is the usual set of batteries B, snugly encased in an open ended fibrous sleeve 64 in such manner that the batteries are connected in series and the zinc cup 66 of the lower battery is accessible at the bottom end of the sleeve, while the metal tipped carbon pole 68 of the upper battery is accessible from the top end of the sleeve.

The head assembly I'his assembly comprises a lens ring 10 of plastic material having a female thread 12 adapted to mesh with the male threads 32 at the front end of the head casing portion 22. The forward edge of said lens ring has an inwardly extending flange 14 which provides a seat 16 against which the lens 18 is adapted to abut. Said lens may be formed from any suitable transparent material such as glass or transparent plastic like methyl methacrylate, vinyl ester resin, vinyl acetal resin or cellulose acetate butyrate. The lens may be in the form of a flat circular disk as illustrated, since it is employed in conjunction with a parabolic reflector, the term lens having been retained by the art although neither surface thereof is curved.

In back of the lens and clamped between the same and the front edge of the head portion 22 is the out-turned angular flange of an electrical conductive parabolic reflector 82. Said reflector is assembled to form with an electric light bulb 84 a prefocused unit in which the reflector serves to conduct the current from one side of the battery B to the lamp. To this end the reflector may have clinched to the rear thereof a threaded ferrule 86 of electrically conductive material, the front end of the ferrule being inturned where it is clinched to the rehector to provide a seat 88 against which the ange 90 of the electric light bulb 84 is adapted to rest. The ilange is pressed against its seat by a plug 92 of insulating material such as that from which the casing |2 is fabricated. Said plug is threaded into the ferrule 86, and to facilitate rotation thereof is provided with a plurality of ridges 64 formed around the rear flange 95. The center of the plug has a large bore 96 running therethrough in which there is freely received the base of the electric light bulb, while a central contact 90 projects beyond the ange 95 so that it may be easily contacted by an element of the electrical system.

The base assembly The base assembly comprises a bottom closure cap |00 of plastic material similar to that from which the casing |2 is molded. The lower end of the cap is closed oi by a bottom wall |02, the top end being open and provided with a female thread |04 which is adapted to mesh with the male threads 23 at the lower end of the body casing portion 20. Between the lower ends of the threads |04 and the bottom wall |02 a substantial space is provided, large enough to receive a goodly portion of a spare bulb |06 lying athwart the closure cap, the walls of said cap surrounding said space being thickened to form a ledge |08 against which the fitting |10 for carrying the spare bulb can be seated. Said fitting, which is made from a single piece of sheet metal, comprises a strap ||2 whose two ends ||4 are arcuately shaped so as to fit within the closure cap at the ledge |08. The center span I6 of the strap is raised and diametrically slitted as at ||8 to accommodate a portion of the flange |20 of the spare bulb |06. The latter is retained by a pair of resilient ngers |22 struck out from the material of the strap and shaped in such fashion as to frictionally hold the base |24 of the spare lamp. The spare lamp fitting is pressed against its seat |08 by a tapering helical battery compression spring |26 of electrically conductive material, the small end of which is adapted to strongly press against the zinc cup 56 of the lowermost cell B, and the large end of which is adapted to rest upon the seat |08. The tip of the spring has an inturned linger |28 which is adapted, when the closure cap is screwed on the base of the flashlight casing, to press against the inner bottom edge thereof to effect a good electric contact with an element of the electrical system now to be described and which is positioned at this point.

The electrical system The electric system comprises a ferrule |30 of electrically conductive material which is nested within the lower end of the casing portion 20 and is there held by an eyelet |32. The lower edge .washer |38.v Rivets |415.; |42 aid in securing the strip tothe casing and also assist inthe. operation of' the switch |8.. The latter is4 of the three step type, such as. shown and described in my cepending application Serial No. 377.983', this switchbeingi particularly adapted; for use with a iiashlight casing of insulating material. The switch is adaptedto make-and break an electric circuitbetween the conductive strip 34. and another electrically conductive strip iM, which is disposed in, the; narrow upper portion of the channell.

'Ehestrip |144; isanchored to the casing and, connectedf to the switch by a rivet |145.v Said strip extends; through the, opening inthe. semi-circular wall 3:4.. beyond the top; end of the channel 38 and thnugh,y the slot E6. The strip M11-.is also provided with a finger |46 which extends parallel v tothel'ongitudinal axis of the head portion. 22 and towardr the lens ring 7:0. The tipof said finger is adapted toI engage the rear'surfaceof the reiiector 82 near the fl`ange= 80. andV during such engagement the finger-'willy be bowed between-said reflector and the inner wall ita of the slot 46 over the fillet 48; this bowing serving both to anchory the stripA |46 and to insuregoodf electric conta'ct between said strip and the reflector as moren fully explained in my copending application Serial No. 503,183; filed September 21, 1943-.

The foregoing portion of the electrical system serves to form one leg of the electric circuit between the batteries B and the electric lamp, the current inl this leg of the circuit passing in order from the zinc cup 66 through the spring |i2t",A ferrule |30, strip |35, switch i8' (when closed), strip Mil, reflector B2, ferrule 85 andflange 9B to. the lamp.

Connection is made between the metallic4 tipped carbon electrode 68 and the centercontact Sid of the, lamp-through. a. contact. strip. |48 or electrically. conductive resilient.materialrsuchA as phosphor bronze, having, a base leg |50 heldagainstI a flat. |.52f at the. bottom of the; semi-circular wall 3.43., Said base leg is connected'- by. acurved. bend |53. t a.v forwardly inclined contact. leg |55 which.

isladapteditofpress against the, center contact 98 off the bulb. In. relaxed position thel contact leg |4= isv disposed as shown in Fig. 6,4 the position thereof when the head assemblyis attached beingshowninFig. 3'.

The base leg |150 is secured' toathe wall 34 byf an eyelet. |55 of electrically conductive material whose lower end is spun over ann electricallyI conductive washer tt resting'on a flat |55 beneath the wall 34, said washer and thel base; leg` |-5i1-Y serving tol distribute the strainv upona the wall; 34 Whensetting theeyelet |56.

The metal clad carbon tip Etf is adapted to.v be pressed' against the lower spun end' of. the eyelet |5'6bythe battery springl |2I.to=.com'plete thezcir-V cuit from said carbon electrode to-.the` center contact' ofthe-'lamp through the eyelet'andtheconaire-achi'eved,l 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 madein. the embodiment above setV forth', it is to be understood that all matter herein set forth. or shown in the accompanying drawings isto: be interpreted as illustrative and f not. in a limiting sense.

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

1. An angle head flashlight comprising a one piece molded plastic casing, including a tubular battery receiving portion and a tubular head whoser axisv of symmetry intersects the axis of symmetry et the battery receiving portion substantially at right angles, the ends of said battery receiving portion and head at said intersection being. integrally connected, and a partition within said casing substantially closing off both said integrally connected. ends, said, partition being formed integrally with the casing and reinforcing the battery receiving portion and head against distortion and breakage.

2. AnA angle head flashlight comprising a one piecey molded plastic casing, including a cylindrical tubular battery receiving portion and a cylindrical tubular head, the axesof symmetry of said head and battery receiving portion intersecting substantially at right.. angles, the walls of said head and battery receiving portion being integrally connected along aline of juncture around said intersection, and a portion of the wall of said head. extending past said line of juncture within said casing to substantially close off' the end of the battery receiving portion connected to the head and reinforce said battery receiving portion and head against distortion and breakage.

3'. An angle head flashlight comprising a one piece molded plastic casing, including a cylindrical tubular battery receiving portion anda cylindrical tubular head of substantially the same diameter, the axes of symmetryof said head and battery receiving portion intersecting substantially at right anglesthe walls of said head and battery receiving portion being integrally connectedalong a line of juncture around said intersection, and a portion ofthe wall of said head extendingv past said line of juncture within said t casing to substantially close off the end of the battery receiving portion connected to the head and reinforce saidV battery receiving portion and head against distortion and breakage.

4. A flashlight as set forth in claim 3, wherein van energizing electric system is provided for carrying current from a battery in the ilashlight casing to a lamp also housed therein, said system.V including a conductive element which freely passes' from the battery receiving portion to the head through an opening in the portion of the head extending into the casing.

5. A flashlight as set forth in claim 3, wherein the battery receiving portion is elongated and has a channel formedv internally therein and extending longitudinally thereof for receiving the bare conductive elements of an electrical system in said flashlight which are adapted to energize a lamp housed in the head from battery cells in said battery receiving portion, said channel lead- To ingto an opening in the wall of the head portion extending within said casing whereby one of said elements may pass therethrough.

6. A ashlight as set forthfin'claim 1, wherein a belt hanger is secured to the battery receiving portion`r near the-end thereof integrally connected 7 to the head, said battery receiving portion being integrally thickened at the point of securernent.

7. A ashlight as set forth in claim 1, wherein a belt hanger is secured to the battery receiving portion near the end thereof integrally connected to the head, said battery receiving portion being integrally thickened at the point of securement by a wide flat disposed internally of the casing and by a wide ridge disposed externally of the casing.

8. An angle head flashlight including a plastic casing having integrally connected tubular head and body portions angularly disposed relative to one another and an integral partition within the casing between said head and body portions to reinforce said casing against distortion and breakage, said partition having an integral wall projecting upwardly therefrom and defining one edge of an opening between said partition and casing, the edges of said wall being backed up by wings integrally connecting said wall to the casing, said wings defining two lateral edges of said opening.

9. An angle head flashlight including a plastic casing having integrally connected tubular head and body portions angularly disposed relative to one another and an integral partition within the casing between said head and body portions to reinforce said casing against distortion and breakage, said partition having an integral wall projecting upwardly therefrom and defining one edge of an opening through said partition, a resilient contact comprising part of an energizing electric circuit for carrying current from a battery in the flashlight casing to a lamp also housed therein, said contact element including a flat leaf spring, the base leg of said spring being secured to said partition, said leaf spring having a contact leg extending angularly to said base leg and pressing against said wall.

10. An angle head flashlight including a plastic casing having integrally connected tubular head and body portions angularly disposed relative to one another and an integral partition within the casing between said head and body portions to reinforce said casing against distortion and breakage, a pair of spaced parallel ridges formed internally and longitudinally of said body portion to define a channel for receiving bare conductive elements of an electrical system in said flashlight which are adapted to energize a lamp housed in the head portion from battery cells contained in said body portion, said channel extending through an opening in the partition.

l1. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said shell arranged for electrical connection with a source of current supply disposed in said shell, one of said conductors comprising a bar extending along the wail of said shell and having an angularly turned portion at its forward end to extend into said angular head, said angularly turned portion being resiliently formed and being arranged to press resriently against said reflector to establish an electrical Contact therewith, and a shelf integrally formed with the wall of said head for holding said bar in a manner to keep said resilient portion in position against the reector.

l2. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, said shell including spaced longitudinally extending ribs formed integrally with said shell, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said shell arranged for electrical connection with a source of current supply disposed in said shell, said conductors lying between said spaced ribs and out of contact with said source of current supply along the length of the ribs, one of said conductors comprising a bar extending toward said head and having an angularly turned portion at its forward end thereby to extend into said angular head, said angularly turned portion being resiliently formed and being arranged to press resiliently against said reflector to establish an electrical contact therewith.

13. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, said shell including spaced longitudinally extending ribs formed integrally with said shell, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, an interior annular conducting ring fastened to the end of said shell spaced from said angular head, a pair of conductors in said shell arranged for electrical connection with a source of current supply disposed in said shell, said conductors lying between said spaced ribs and out of contact with said source of current supply along the length of the ribs, one of said con.. ductors comprising a bar extending toward said head and having an angularly turned portion at its forward end to extend into said angular head, said angularly turned portion being resiliently formed and being arranged to press resiliently against said reflector to establish an electrical contact therewith, the other of said conductors extending toward and being connected to said annular ring.

14. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said shell arranged for electrical connection with a source of current supply disposed in said shell, an integral molded partition bridging said shell substantially adjacent the junction of said shell and said head, there being an opening between said partition and the interior wall of the shell to provide a passage for one of said conductors to extend from said shell into said angular head, a shelf associated with the wall of said head adjacent said opening for holding said one of said conductors extending through said passageway, a conductor element carried by said partition, portions of said conductor element exposed on opposite sides of said partition, one of said portions comprising a. terminal connection for one of the terminals of said source of supply, and a spring nger held by said other portion to form a contact member for one of the terminals of the bulb of said assembly carried by said head.

15. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, spaced longitudinally extending ribs integral with said shell and forming a channel, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said shell lying within said channel and arranged for electrical connection with opposite terminals of a source of current supply disposed in said shell, an integrally molded transverse partition disposed at the juncture of said shell and said head and extending thereacross, said. partition forming an abutment against which said source of current supply is held, there being an opening between said partition and the interior wall of said shell, said opening registering with said channel for one of said conductors to extend from said shell along said channel and into said angular member, a ringer carried by said partition and against which the bulb of said assembly carried by said head yieldably presses, and a fastening member for said nger mounted upon said partition and having means extending through said partition substantially centrally thereof, said means being exposed on the side of said partition opposite to said finger to form a terminal connection for one of the terminals for said source of current supply.

16. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, spaced longitudinally extending ribs integral with said shell and forming a channel, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said shell lying within said channel and arranged for electrical connection with a source of current supply disposed in said shell, one of said conductors comprising a bar extending along the wall of said shell and having an angularly turned portion at its forward end thereby to extend into said angular head, said angularly turned portion being resiliently formed and being arranged to press resiliently against said reector to establish an electrical contact therewith, and a shelf integrally formed with the wall of said head, said shelf being inline with said channel for receiving said bar and holding said bar in a manner to keep said resilient portion in position against the reflector.

17. In a device of the class described, a molded insulation casing having a substantially elongated shell and an angularly formed head integral therewith at one end, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said shell arranged for electrical connection with opposite terminals oi a source of current supply disposed in said shell, an integrally molded transverse partition disposed at the iuncture of said shell and said head and extending thereacross, said partition forming an abutment against which said source of current supply is held, there being an opening between said partition and the interior wall ci? said shell, one of said conductors extending from said shell through said opening and into said head. a nger carried by said partition and against which the bulb of said assembly carried by said head yieldably presses, and a fastening member for said finger mounted upon said partition and having means extending through said partition substantially centrally thereof, said means being exposed 10 on the side of said partition opposite to said finger to form a terminal connection for one of the terminals for said source of current supply.

18. An angle head flashlight including a plastic casing having integrally connected tubular head and body portions angularly disposed relatively to one another and an integral transverse partition within the casing disposed at the juncture of said head and body portions to reinforce said casing against distortion and breakage, there being an opening between said partition and the interior wall of said body portion, a pair of spaced parallel ridges formed internally and longitudinally of said body portion to dene a channel for receiving bare conductive elements of an electrical system in said flashlight which are adapted to energize a lamp housed in the head portion from battery cells contained in the bodyportion, said channel extending through said opening.

19. An angle head flashlight comprising a onepiece molded plastic casing, including a tubular battery receiving portion and a tubular head whose axis of symmetry intersects the axis of symmetry of the battery receiving portion substantially at right angles, the ends of said battery receiving portion and head at said intersection being integrally connected, a bulb and reflector assembly carried by said head, a cap including a lens for holding said assembly positioned within said head, conductors in said casing arranged for electrical connection with a source of current supply in said battery receiving portion, and a transverse partition within said 'casing disposed at the juncture of said battery receiving portion and head, said partition being integral with the casing and reinforcing the battery receiving portion and head against distortion and breakage, there being an opening between said partition and the interior wall of said battery receiving portion, through which one of the conductors extends from said battery receiving portion to said head, and there being an opening in said partition at substantially the axis of symmetry of the battery receiving portion, through which second opening another conductor extends from said battery receiving portion into said head.

BERNARD FRANCIS MULDOON.

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

UNITED STATES PATENTS Number Name Date 1,408,527 Lyhne Mar. 7, 1922 1,599,113 Cargill et al Sept. 7, 1926 1,680,484 Stimson Aug. 14, 1928 1,820,960 Champagne et al. Sept. 1, 1931 1,905,787 Barber Apr. 25, 1933 2,153,814 Seiss Apr. 11, 1939 2,235,025 Kopp Mar. 18, 1941 2,249,692 Gelardin July 15, 1941 2,259,673 White Oct. 21, 1941 2,290,487 Muldoon July 21, 1942 2,298,042 Desimone Oct, 6, 1942 2,304,433 Zimmer Dec. 8, 1942 2,330,673 Braum Sept. 28, 1943 FOREIGN PATENTS Number Country Date 536,657 Great Britain of 1941

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