US 2568229 A
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Description (OCR text may contain errors)
Sept. 18, 1951 A. w. GARDES EXPENDED CLIP CARTRIDGE CHUTE FOR MACHINE GUNS Filed March 5, 1948 2 Sheets-Sheet 1 I l a I q I J4 i a A W. 4 A r g B O O 0o 9 G M W W. .||n a 2 25 a. M m l ,2 mull Sept. 18, 1951 A. w. GARDES EXPENDED CLIP CARTRIDGE CHUTE FOR MACHINE GUNS Filed March 5, 1948 2 Sheets-Sheet 2 8 m H a N m M MM .d 4 8 L m 4 v l Y B m. a a a Patented Sept. 18, 1951 EXPENDED CLIP CARTRIDGE CHUTE FOR MACHINE GUNS Alfred W. Gardes, Detroit, Mich., assignor to McCord Corporation, Detroit, Mich., a corporation of Maine Continuation of application Serial No. 507,060,
October 21, 1943.
1948, Serial No. 13,154
This invention relates to a new and improved construction of a chute for carrying away the expended clips ejected from aircraft machine guns and to a method of making the tubing which forms such a chute.
The shells used in the machine guns employed in aircraft are fed to the gun in the form of an endless belt formed by a plurality of metal clips provided with two spaced loop portions and a third loop portion, the third loop being adapted to fit between the pair of spaced loops of an adjacent clip. The shell casings of the shells or bullets fit snugly within the two spaced loops of the clips which are made of spring metal while the third loop of the adjacent clip partially surrounds the shell casing but with sufiicient clearance to permit the clip to rotate freely upon the shell casing. The shells therefore act in a manner similar to the pivot pins of a chain. When the bullets are fired from the gun, the shell casings are ejected downwardly from the gun by the force of the expanding gases resulting from the firing of the shell while the metallic clips are ejected laterally from the side of the gun by a suitable ejection device operating in timed relationship with the firing of the gun.
The above features are characteristic of the Browning machine guns that are more or less standard equipment for the United States armed forces. These Browning machine guns are mounted in many different types of airplanes and are employed both as turret guns and wing guns. When used as turret guns, the clips which are ejected laterally from the side of the gun have heretofore been permitted to pile up on the floor of the turret. When the Browning guns are used in a fixed position in an airplane wing, it has heretofore been the practice to provide a chute of relatively large cross-sectional area into the upper end of which the clips are ejected by the clip-ejecting mechanism of the gun and the lower end of which chute is suitably secured to the wing structure and passes through an aperture provided in the skin on the underside of the airplane wing. As heretofore constructed, these chutes were made many times larger in crosssectional dimension than the clips which are intended to pass through them, so that the chutes would not present any obstacle to the free passage of the metallic clips therethrough and thus permit them to fall freely by gravity through the chute and from the plane.
It has been found, however, in actual practice that when the airplane is traveling at a very high speed, such as is reached, for example, when the This application March 5,
plane is in a diveparticularly a power divethe air pressures which are built up at the lower open end of the clip chutes overcome the gravitational pull on the clip and thus not only prevent the clips from passing out of the lower open end of the chute but the pressures frequently blow or force the clips upwardly into the upper portion of the chute. As the machine guns fire with great rapidity and the expended clips are being forcibly ejected into the clip chutes in a steady, almost uninterrupted, stream, the clips frequently fill the relatively large clip chute and become tightly jammed therein, thereby rendering the machine gun inoperative and useless. When the clips do become so jammed and choke up the clip chutes, theyare wedged in the chute very tightly because of the high velocity with which the clips are ejected from the gun, and consequently a jammed expended clip chute cannot be cleared during a flight but the trouble can only be corrected after the plane has been landed.
When the clips are ejected from a turret machine gun and permitted to pile up on the floor of the turret, the pile of clips which accumulates in the turret, particularly after an extended use of the gun, seriously hampers and impedes the turret gunner.
The principal object of the present invention is to provide a new and improved construction for an expended clip chute for aircraft machine guns by means of which the foregoing objections will be entirely obviated.
Another object of the present invention is to provide a clip chute so constructed and arranged not only so that no obstruction will be presented to the downward passage of the clips under the force of gravity, but so that a plurality of obstructions are presented which prevent the clips from moving upwardly in the clip chute as a result of high air pressures.
A further object is to provide a clip chute of the character described which is made of flexible material whereby the chute, when it is attached to a pivotally mounted gun such as is employed in a gun turret as distinguished from a fixed wing gun, will not interfere with the pivotal movements of the gun in either a, horizontal or vertical plane in training the gun upon a target.
Another object is to so construct the chute that the desired flexibility thereof, as above described, may also be employed, by mounting the discharge or outlet end of the chute loosely, to cause the vibratory movements produced by the engines and propellers of the plane to impart a continuous shaking action to the chute which facilitates the diagrammatic view assent free passage, and prevents any jamming, of the clips within the chute.
A further object of the invention is to provide a clip chute of the character described with a new and improved attachment fixture or. bracket by means of which the chute may be quickly and readily attached to a standard machine gun, and to so construct said fixture or bracket that the inner wearing surfaces thereof against which the clips are forcibly ejected by the clip-eject-.
ing mechanism of the gun may be readily given a hard, wear-resistant coating. or plating of. a
suitable metal, such as chromium, that will insure a relatively long period of longevity.
Another object is to provide a clip chute of the character described of comparatively simple and inexpensive construction, of comparatively light weight, yet withal of very sturdy construe tion capable of withstandin the rough usage of combat conditions.
Still another. object of the invention is to provide a clipchute capable of handling a column of spaced clips as such column is ejected by a machine gun. In handling .such column, the clip 'c'huteprevents the individual clips in the column from becoming laterally displaced with respect to one another by a distance greater than somewhat less than the width .of a single clip. Under such circumstances, the vclips maybe blown back by the mouth of the clip chute or may otherwise beslowed down in their movement in the column by the inertiaofthe column due, to the inertia.
of each succeeding clip and will maintain a continuous movement of the clips through the clip chute from which they. will be discharged into the atmosphere.
Other and further objects oithe invention will be apparent by. reference to. the accompanying drawings of which there aretwo sheets, which, by way of illustration...show preferred embodiments and the principles thereof and. what I now consider to be the. best mode which I have contemplated applying. these principles.
Other embodiments of the invention embodying the same or equivalent principlesmay be used and structural changes may be made as desired by. those skilled .in .the art without departing from the present invention and the purview of the appended claim. I also contemplate that of the several different features. of my invention, Q
certain ones thereof may be advanta'geously employed in some applications separate and apart from the remainder of. the features.
In the drawings:
Fig. 1 is a somewhat diagrammatic view of an airplane turret equipped with a pivotally mounted machine gun and showing an expended clip chute constructed in accordance with the principles of the present invention attached to the gun and leading to a suitabl'e'aperture provided in the floor of the turret through which the expended clips are ejected;
Fig. .2 of the drawings isa similar somewhat in vertical cross-section throughan airplane wing showing a fixed machine gun mounted therein and having a clip chute attached thereto;
Fig. 3 is an enlarged side elevation of the midgstantially-on the lines 6-6, 'l1 and 8-8 of Fig. 9 is a sectional detail taken substantially on the line 9-9 of Fig. 8;
Fig. 10 is an enlarged sectional detail of that portion of the clip chute shown in Fig. 8 and enclosed within the area of the dot-and-dash line H];
Figs; 11 and 12 are views in side elevation of a construction of the flexible clip chute in which the exterior sitle walls thereof have secured to them -a plurality of guide rods or wires which serve to prevent malalignment of adjacent convolutions of the chute as a result of the flexing or curving of the chute.
In Fig. 1 of the drawings there is shown a cross-sectional view of a gun turret such'as is employed in combat airplanes and equipped with what might be termed a 'dirigible machine gun by which is meant a gun that is pivotally mounted to be trained by the'gunner upon a target. The constructional details of the turret or gun mounting and likewise of the machine gun per se form no part of the present invention. It wil1 be sufiicient tonote that the turret consists'ofa base mounted for rotation about the vertical central axis'of the turret upon a suitable supporting structure indicated by the reference character H. The'machine gun I is pivotally mounted as at I3 upon any suitable support, suchas Id.
In Fig. 2 of the drawings the machine gun l5a is shown as fixedly secured by the brackets l6 and I! in a wing [8 of an airplane. The machine guns I5 and 15a shown in Figs. 1 and-2 are provided respectively with expended clip chutes constructed in accordance with theprinciples of the present invention which are indicated generally by the reference characters a and 26b. The construction of the'clip chute and of the means for attaching it to the machine gun can best be understood generally by reference to Figs. 3 and 4 of the drawings, 'whereinis'shown that portion of a standard machine gun in which the cartridge clip-ejecting means is housed. As shown in these figures, the machine gun has secured to the side faces thereof bracket members 2 I, which are provided with a plurality'of laterally projecting aperportion of a machine gun showing the improved tured lugs 22 in which is received a pin 23 adapted to be readily withdrawn from or inserted into the apertured lugs 22, and which serves for attaching to the gun an expended clip-ejecting chute through which areejected the metallic clips that are employed for securing the shells fed to the gun in an endless belt as hereinbefore described.
Fig. 3 shows a clip chute of the present invention which consists ofthe main chute portion indicated generally by the reference character 20 attached to the gun by means of a fixture or bracket indicated generally by the reference character 30.
As will appear from an inspection of the drawhugs, and particularly Figs. 5 to 10, inclusive, the chute 20 is preferably formed of a strip 26 of thin spring sheet metal. This strip is also preferably formed so that the lower longitudinally extending section 2611. of the strip is offset inwardly from the upper longitudinally extending section 28b thereof, as shown best in Fig. 9 of the drawings; an operation which can be readily performed by rolling a plain fiat strip of material. Between the offset sections are shoulders 26c, likewise extending longitudinally of the strip. After the fiat strip of material has been rolled or otherwise fabricated to provide the ofiset portions 26a, 26b, and the shoulders 260, the strip is then spirally wound upon a mandrel of generally rectangular cross-section so as to form the convolutions indicated in Fig. 9 in which the portion 26b of each convolution fits neatly about the smaller offset portion 26a of an adjacent turn or convolution of the spiral. During the winding of the strip, it is necessary to tension the strip in order to stretch the outer section 2% around the corners of the mandrel so as to continue the shoulder 26c around such mandrel corners and so that the length of the outer sections 26b will be longer and fit over the inner sections 2611.
The winding of the strip upon a rectangular mandrel forms the chute 20 into a hollow, substantially continuous tube of rectangular crosssection as indicated in Fig. 8 of the drawings through the interior of which the expended clips C are adapted to pass.
Suitably secured to the upper end of the spirally wound spring steel chute 20 is an attachment fixture 21 formed of heavier sheet metal and of generally U-shaped configuration, the fixture 21 having a plurality of downwardly extending lugs 21a which are preferably brazed or otherwise suitably secured to the helical tube 20. The side legs 21b of the fixture 21 are provided with keyholeshaped slots or apertures, in the circular portion 210 of which is adapted to be received the threaded studs 28 which project laterally from washers 21d brazed or otherwise secured to the opposite sides of the attachment bracket 30 presently to be more fully described, the open ended straight portions 21d of the keyhole slots being provided for facility in quickly assembling the chute 20 to the attachment bracket 30. In order to more firmly secure the chute 20 to the attachment bracket 30 and prevent movement thereof, a washer 3| is placed over each of the studs 28 and said washer is provided with an inwardly extending circular boss 3la which fits snugly within the circular portion 210 of the keyhole slot; said washer is also provided with a laterally extending tongue 3lb which fits neatly within the straight portion 21d of the keyhole slot. Nuts 32 are threaded upon the studs 28 to clamp the U-shaped attachment fixture 21 securelyto the attachment bracket 30.
The bracket or fixture 30 is in the form of an L shape which serves to direct the expended clips that are ejected laterally from the side of the machine gun in a horizontal direction, downwardly into the clip chute 20. The horizontal portion of the bracket is formed by two laterally projecting side walls or legs 30a. and 30b (see Fig. 7) which are suitably formed at theirupper ends to engage with cooperating parts formed in the machine gun for engagement by the legs 30a and 30b of the attachment fixture to locate it properly in position with respect to the clip-ejecting mechanism of the gun. In addition to the side walls 30a, 3%, the fixture 30 is also provided with a top wall 300 and a bottom wall 300. which in cooperation with the side walls 30a. and 3012- form an open rectangular guideway or chute through which the clips pass in a horizontal direction. Intermediate the ends of the walls 30a to 30d, inclusive, the fixture is curved as indicated at 30c to direct the expended clips downwardly into the vertical leg portion of the L-shaped fixture. This vertical leg portion is formed by a U-shaped fixture. This vertical leg portion formed by a U-shaped section 30 (see Fig. 6) the side walls 309 of which have formed at their extremities the laterally extending flanges 3011.. The back cover plate 302' has its side edges bent around as indicated at 309' so that the back cover plate em may be slidably and detachably mounted upon the main fixture, the lower wall 30d of the chute as above described being formed integral with the back plate 301. The purpose of mounting the back cover plate slidably and detachably upon the main fixtur is to enable the inner face of the lower vertical wall portion 30k of the wall 30c of the fixture 30 to be exposed for plating the wall of the attachment fixture 30 with a hard, wearresistant coating of suitable metal, such as chromium. If the attachment fixture were made of a single piece of metal, the inner surface of the wall 3074: of the attachment fixture could not be plated as. the plating could not be effectively thrownas the expression is used in the plating art-down into the inside of a closed chute.
As the flexing of the spirally-wound fiat steel strip portion 20 of the chute tends to slip the outer ofiiset or enlarged sections 2612 of an adjacent convolution out of engagement with the cooperating inner offset section 2611 of the adjacent convolution and thereby result not only in misalignment of the tube convolutions and also to result in gaps or openings between adjacent convolutions, means are provided to prevent undue lateral movement between adjacent convolutions, to hold the convolutions in proper alignment, and to bridge any gaps which might be caused by flexing the tube. Such means comprises the rods 35 which as shown in Figs. 11 and 12 are secured in staggered, overlapping relationship upon all four sides of the chute 20. Each rod 35 is provided at one end thereof with an inwardly bent enlarged head 35a which is brazed, welded or otherwise suitably fixedly secured to one of the convolutions of the chute. The other end of each rod is provided with an enlarged head 35b. Each rod 35 passes slidably through an eye 36 which is also fixedly secured to a convolution of the chute and serves as a lmiting stop against which the enlarged head 35b engages, as shown more clearly in Fig. 12 of the drawing. The rods 35 thus serve to limit the opening movement of the adjacent convolutions and thereby prevent misalignment thereof as hereinbefore described.
The manner in which the parts heretofore described are fabricated is as follows: The fabrication and formation of the chute portion has already been fully described. After the chute has been formed into the rectangular convoluted form, the rods 35 are attached and spaced in overlapping, staggered relationship, as indicated in Fig. 11. After the fixture 30 has been formed into the desired shape with the projecting legs 30a, 30b and 300 and also with the flanges 30h at the extremities of the walls 300. and 30b, the fixture is placed in a suitable electro-plating bath and a coating of wear resistant metal is placed thereon. The back plate 301 of the fixture is also similarly plated after which the back plate 302' is slid upon the flanges 30h and in a position such that the leg 30d of the plate will occupy a position such as is shown in Fig. '7. The chute 20 to which the attachment fixture 21 has been suitably secured, as by brazing is then slid over the lower end of the fixture 30, the open ends of the shtraight portions 21d of the keyhole slots being slid over the studs 28. The washers 3! are then placed over the studs'and the nuts 32 threaded onto the-bolts and tightened thereon to hold the chutefirmlyattac'hed to the fixture 30. The dimension of the chute relative to thelower end of the-fixtureSfl is such that when the chute has beensecured to the attachment fixture Silthe upper endof the chute engages with the slidable backplate 392' of the fixture and holds it against downward movement 'andsecurely in proper position.
The first clip i chutes constructed in accordance withthe foregoing principles were made of. strip steel approximately three-quarters of an inchin width andwhile these provedquite satisfactory in practice, hcwever, it was'found that when the chute was flexed beyond a certain amount it was desirable. to .eznplcy the rods 35 toprevent-adjacent convcluticns or the spirally wound strip from shifting laterally out of proper alignment. The use of .thethree-quarters of an inch wide strip coupled-with the rods 3:? resulted in impressing to'- great limitation upon theextent to which the chutecould be fiexedand consequently-a further improved construction was.deveioped. This improvedand preferred construction is best illustratedin Figs. 3, 8 and :10 of the drawing. .It consistsin emplcyinga much narrower strip of flat-steel for forming the chute, .the width of such steelbeing of theorder. of approximately three-eighths of an inch in width. After the tube has been fabricated by winding the narrower strip'upon a square mandrel; it being understood that before winding the strip/it is offset as indicated at ZEa'and 26b in FigmQ of. the, drawing, there is bonded to the two narrow side twalls of the tube a continuous strip ofcrubberor other suitable flexible material Ml,
asindicated in Figs. 3, 8 and 10 of the drawing. Therubber of the bands is bonded to the metal ofeach convolution of the strip by sulphurization and-heat treatment until the surfaceto be applied tozthe metalis softened sufficiently so that it may be. applied to the metal andfirmlypressed into contact therewith so that upon coolingit is so firmly united tothe metal that it is practically impossible for it to be detached therefrom.- Itwillbe apparent thatthe-bands may be adhesively securedto the tube convolutions in any other manner which-it maybe .desired to employ. By reason of the use of the narrower strip steelmaterial forming the convoluted tube andalso, because of the securing of the; strip-of. flexible rubber .40 .to 'theconvolutions thereof, the flexible properties of the tube or ohuteqare somewhat diiierent. The use of the narrower. metal permitsthe tube to be bent or curved ona radius of much smaller curvature than is :possible when the wider strip material is used as willb'e readily apparent.- Thesubstitution of.- the strips ofv flexible rubber lilalongthe two sides. of the tube changes the limiting factors which areimpressed upon the structure when the slidable'metal rods are employed, the rubber strips functioning .to preventmisali'gnment of the adjacent-convolutions when the 'tubeis bentor 'fieXedthrough a bend of very sharp or short curvature and holding the edges of .the adjacent convolutions in accurate alignment with each.other.,
It will also be apparent that it will be much more diiiicult to bend the tube.byexpandingandcontracting the sidesof the tube to which the bands '4ll-gare attachedthan it willzbe to-bend the tube at 90 degrees withrespect to-the bands. .The-stretchtary' assembly which can be. readily attached to the side of the machinegum-the legs Maand 30b being entered into the suitable slots.- provided in the bracket 2| on-the-side of. the .gun for. engage.- ment with-the cooperating parts formed in the gun. The rod 2-31is then passedthrougha suitable hole 513 .(Fig. 6) provided. in the leg.30b.of the fixture andthroughanotheinhole. 59 provided in a small bracket (Fig- 4) that is attached to the side wallofthe fixture-311.
When the chute is attached-to a. fixed-wing gun thelower endofthe-chute fiflaipasses through'a suitablehole- 42:. Fig. .5) provided in the skin 43 of the .-x,ving is; As.=clearly shown in Figiflithe lower end ofthe chute proj ects down. below. the
lowerskinof the wing. anda clearance space is left between the chute and a bufferstrip 44,.thereby to permit the .chute to-have a shakingeor. vibrating section-imparted to .it by the. vibrations. of the airplane.-
In the actual operation of. the-.gun,.-.the iclips areeiectedlaterallyzina horizontal direction in a column of spaced clips from-the side .ofhthe gun into the attachment. fixture .36 zby which they-are deflected-by the .curved Wall 38cc thereof downwardly in a vertical .direction. into .the: chute; 20. As will be. readily seenfrom. the foregoing'description .andparticularly by reference to .Eig- 9 of ,the drawing, the overlapping .of the inner oflsetends of each convolution .ove'rethe adj acentouter. ofisetportion 2'61; zofthe next convolution results -.in the form-ationin the interior of the chute of.-a substantially smooth surface or at:.least one-.in which there-are no .projectionsthan. can tend .to
impedethe .downrvard passage. of.,,the-..-.-clips through the: chute... This overlapping, however, results intheformation -of..a slight projection bythe lower edgeiof each-inner offset portion 26a of each convolution against. which .the. clips will :tend .to strike if the air pressure on-.the.-.lower endof the chuteis sufficientlyhigh ;to=.tend-.to move the clips-upwardly... As will be seen-from thedotted line showingsof -.the;clip in Fig. 8 of the =-drawing,- .the' cross-sectional .'dimension .of the chute is but: slightly larger-thanthe outer dimensions-of the clips. As, a result, it is impossible tor theclipsto-turn-or twist and thus become caught and therefore wedged in the chute. Asthe gun continues firing and the clips areejected rapidly into the'chute theclips pass throughthe chute in a vertical'column so that even if thecair pressures are sufficiently high as to tend to-blow the individual =clips: .backwardly .and upwardly into the chute; the-inertia. ofethe vertical column .of
clips. will always .be; sufficient-to overcome. the air pressure. In; addition,-;the, continual, shaking imparted to .the.chute -.by-.the vibrations; of the gum-together, with the loose mounting of. the lower :end of the-chute, eifectively .prevents any Jamming .ofthe clipswithin the chute.
.. precise details setforth, butdesiregto avail. myself ofysuch changes and .alteratiqns'as fall within the purview of the followingclaim.
This aapplicationis ;a continuation flof my pendinsappli a Qn,: Ser a1 .:No. 507, 60,.- ;fi1e. Ocztober 21,; 19%3; ;.for Expended; iclip. partridge Chute fonMachin Guns? which;hasb n-aban- Cloned.v
e th. a mach ne 1 su p nded t i se c ip te m ri neie n ally v rtical flexible tube formed of a single strip of thin resilient material spirally wound to form overlapping convolutions and to define a tube of rectangular cross section generally conforming to the shape of the expended cartridge clip and having a cross section large enough to accommodate the passage of only a single clip at one time, an attachment bracket for detachable engagement with the machine gun, said attachment bracket being internally coated with a hard wear-resistant coating, means for detachably securing said tube to said bracket, said attachment bracket being formed of a strip of sheet metal of generally U-shaped cross-sectional configuration and provided with a detachable guide plate bridging the open legs of the U whereby the entire inner surface of the U-shaped configuration of said attachment bracket may be completely exposed for subjecting the interior to the action of a plating bath, said attachment bracket and guide plate being provided with cooperating interengaging means for holding said guide plate against lateral movement relative to said attachment bracket, and said clip chute being provided with means for engaging said guide plate and holding it against vertical displacement relative to said attachment bracket.
ALFRED W. GARDES.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 800,054 Ayres Sept. 19, 1905 1,198,392 Brinkman Sept. 12, 1916 1,308,665 Douglas July 1, 1919 1,565,278 Jorgensen Dec. 15, 1925 1,886,218 Olin et al. Nov. 1, 1932 1,905,824 Dysthe Apr. 25, 1933 2,055,771 McLaughlin Sept. 29, 1936 2,166,109 Karmazin July 18, 1939 2,336,557 McCallister Dec. 14, 1942 2,305,667 Brentnall Dec. 22, 1942 2,310,884 Trevaskis Feb. 9, 1943 2,323,430 Trotter July 6, 1943 2,351,370 Schaafi June 13, 1944 2,384,678 Holton Sept. 11, 1945 2,417,676 Chernack Mar. 18, 1947 2,479,288 Allen Aug. 16, 1949 FOREIGN PATENTS Number Country Date 785,893 France May 2'7, 1935 822,975 France Oct. 4, 1937