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Publication numberUS2757576 A
Publication typeGrant
Publication date7 Aug 1956
Filing date7 Feb 1949
Priority date7 Feb 1949
Publication numberUS 2757576 A, US 2757576A, US-A-2757576, US2757576 A, US2757576A
InventorsChapman James E
Original AssigneeGarrett Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Ammunition feed booster
US 2757576 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Aug. 7, 1956 J. E. CHAPMAN l AMMUNITION FEED BOOSTER 2 Sheets-Sheet 1 Filed Feb. '7, 1949 23 ZV1/wrom /4/Vf5 CHAP/ww AJg- 7, 1956 J. E. CHAPMAN 2,757,576

AMMUNITION FEED BOOSTER Filed Feb. 7, 1949 2 sheets-sheet 2 (/A/'ffs CHA/OMAN 6x /f/.S A Walen/5%;

AMMUNITION FEED BOSTER James E. Chapman, Los Angeles, Calif., assigner to The Garrett Corporation, Los Angeles, Calif., a corporation of California Application February 7, 1949, Serial No. 74,972

14 Claims. (Cl. 89-33) This invention relates to ordnance and more particularly to ammunition feeding means for use in connection with universally mounted firearms of the automatic', rapid-lire type such as those used in military aircraft. Specifically, the invention pertains to a power-actuated booster adapted particularly for feeding ammunition to a gun of the heavier type.

An aircraft machine gun operated under remote control is usually supplied by an ammunition belt which travels from an ammunition magazine through a feed chute to the gun. In such gun installations, it is common to utilize the explosive power of the cartridges being tired to provide the energy required to actuate the ring mechanism and that necessary to feed the ammunition belt from the magazine to the gun. As is well known to those versed in the art, considerable energy is required to feed the ammunition belt and this is due to several factors.- In the first place, the weight of a belt of arnmunition is substantial and, for this reason, considerable inertia must be overcome whenever feeding of the belt is started, which may occur frequently since the gun 4is usually tired in bursts. Secondly, the feeding movement of the ammunition belt is resisted by friction which occurs within the belt structure and between the belt and the feed chute. Thirdly, feed loads may also be increased at times by violent flight maneuvers of the airplane. As will be apparent, when the explosive power of the cartridges being tired constitutes the sole prime mover for feeding the ammunition and the firing mechanism is thereby required to perform the Work discussed above, it frequently occurs that the firing mechanism is overburdened, with the result that the rate of tiring is substantially lessened. Moreover, due to the excessive load imposed on the gun mechanism, jams, mistires, and other malfunctions may occur and thus the gun may become inoperative or inefficient at a time when its use is direly needed.

In an effort to overcome the difficulties outlined above, power-actuated booster means have been proposed, such means being in the nature of a driving mechanism interposed between the ammunition magazine and the gun and operative to advance the ammunition belt with a step-bystep motion to the gun. While such booster means are used quite extensively `and with some degree of success,

they are subject to certain disadvantages. Forexample, some feed boosters employ constantly operated electric motors and slip clutches which are adapted to slip after the ammunition belt has been fed a predetettmined amount and, as will be apparent, such clutches are subject to wear which eventually renders them ineffective. Moreover, since the feeding force of such boosters is applied continuously, undue strain may be placed upon the gun mechanism or the components of the cartridge belt. In another type of booster device, a pawl and ratchet mechanism is utilized to index the belt feeding sprocket with an intermittent motion and such mechanism is quite apt to wear and is subject to breakage. devices, the ammunition belt, which is fed upwardly to In previous booster 7 United States Patent O Patented Aug. 7, 1956 ICC the gun and which has considerable Weight, tends to move backwardly and, if this retrogressive movement is not adequately checked, undue strain is imposed on the gun mechanism, and any slack occurring between the links of the cartridge belt must be taken up prior to the actual feeding of the belt. Moreover, due to the fact that torque is applied by the electric motor at a point relatively close to the axis of rotation of the motor shaft, a motor of relatively large capacity is required in order to obtainthe torque necessary to overcome friction, the weight ofl the ammunition belt, and inertia.

It is an important object of this 4invention to overcome the deficiencies of prior booster devices by providing an ammunition feeding means which is relatively simple in construction, yet highly efficient in performing its intended function.

Another object is to provide a booster which includes a feeding sprocket, an electric motor within the sprocket, and power transmission means between the motor and the sprocket for rotating the latter, the arrangement of the transmission elements being such that torque of high amplitude is produced and applied to the feeding sprocket so that the use of a motor of smaller size than those heretofore employed for like purposes is possible.

Another object is to provide an ammunition feed booster which, in addition to providing the power necessary to feed the ammunition belt to the gun, also includes means for locking the belt subsequent to each advancement thereof so that retrogressive movement or rollback of the belt, which would cause slackness therein, is effectively prevented and a more uniform feeding of the belt is attained.

Another object is -to provide a booster of the character referred to, in which the operation of the electric motor is substantially continuous so long as the gun is tiring, the operation of the motor being controlled in response to movement of the ammunition, belt itself, a pressure switch in the electric motor circuit being actuated directly by the belt when the latter meets with resistance so as to immediately arrest the drive and prevent overfeeding and excessive buckling of the belt and strain on the gun tiring mechanism.

Another object is to provide a booster of the type indicated which comprises a compound differential planetary gearing between the electric motor shaft and the belt-feeding sprocket. The planetary gears remain in mesh with their respective orbit gears and in driving connection with a sun pinion on the motor shaft. One of the orbit gears may be locked against rotation so as to elect driving of the feeding sprocket without the use of oscillating pawls or other elements which might allow backlash or slack between the driving members and the elements of the ammunition belt.

A further object is to provide an ammunition feed booster which has a free-wheeling clutch which, when the booster motor is de-energized, permits the booster sprocket drum'to rotate in the direction of feed to allow the ammunition belt to be drawn upwardly from the magazine and inserted in the chute and gun mechanism.

A still further object is to provide an ammunition feed booster having manually controlled means for rendering the anti-rollback clutch means inoperative so as to permit reverse rotation` of the feeding drum and thus make it possible to withdraw or unload the remaining unred portion of the ammunition b elt from the chute in the reverse direction.

Further objects of the -invention will be vapparent from the following specification and from the drawings, which are intended for the purpose of illustration only, and in 0 which:

Fig. l is a side elevation of a machine gun installation showing a preferred form of the ammunition feeding means or booster applied to use therewith;

Fig. 2 is an enlarged longitudinal part sectional View through the booster, taken on line 2-2 of Fig. l;

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

Fig. 4 is a longitudinal sectional view of the drive end of the booster, taken on line 4-4 of Fig. 3;

Fig. 5 is a cross-sectional view, taken on line 5-5 of Fig. 4,' and Fig. 6 is a cross-sectional View, taken on line 6--6 of Fig. 4.

Referring first to Fig. 1 of the drawings, the reference character 10 designates a conventional, high caliber machine gun of the type commonly employed in military airplanes, and 11 indicates the tiring mechanism of the gun. Ammunition is supplied to the firing mechanism 11 from an ammunition box 12, and passes upwardly thereto through a chute 13. The machine gun 1t) is remotely controlled by a push-button switch 15 which may be located at any desired location within the airplane, such as on the pilots control stick in the usual manner. An electric cable 16 extends from the switch 15 to a solenoid-operated mechanism 17 which functions, when energized, to effect continuoustiring of the gun.

The ammunition box 12 houses a motor-driven booster 20, forming the subject matter of the present application, which functions to feed the ammunition from the box to the gun in the manner to be hereinafter explained. The motor-driven booster 20 is energized and controlled by an electric cable 21, the arrangement being such that the booster is energized only when the pilot closes the push-button switch 1S.

As shown in Figs. 2 and 3, each cartridge 25 for the machine gun has a cylindrical shell 26 that tapers to a reduced diameter to embrace a projectile 27. The cartridges are interconnected by a disintegrating ammunition belt 28 which comprises a series of sheet metal links 29, this structure being commonly employed. Each link 29 is provided with two loops or bands 30 which receive one of the cartridges 25 and is formed with a third central loop 31 which engages an adjacent cartridge of the series. In effect, each cartridge serves as a hinge pin for pivotally interconnecting two of the links 29. During operation of the gun 10, thering mechanism 11 automatically removes the cartridges 25 in sequence from the belt 28 of ammunition in the course of rapid fire, the individual links 29 being automatically released and discarded.

The motor-driven booster 20 is constructed and arranged as next described. Secured to one side wall 33 of the ammunition box 12, by screws 34, is a cylindrical end member 35, to the inner end of which is secured, by screws 36, one end of the cylindrical casing 37 of an electric motor 38. Reduced portions of the end member 35 and the motor casing 37 support an antifriction bearing 39. The opposite reduced end of the motor casing 37 also carries an antifriction bearing 40. A belt feeding sprocket 42, in the form of a tubular shell, is rotatably supported in part by the two antifriction bearing 39 and 40 and is provided with longitudinally spaced rings 43 which are provided with alternate semicircular recesses 44 and teeth 45 in their peripheries (Fig. 3). The ammunition belt 28 extends partly around the peripheries of the rings 43 with the shells 26 of the cartridges 25 engaging in the recesses 44 thereof so that upon rotation of the feeding sprocket 42 the rings act in the manner of a sprocket to feed the cartridges 25` and links 29 upwardly through the chute 13 toward the machine gun 10.

Attached to the other side wall 47 of the ammunition box 12 by screws 48 is a second end member or cap 49 which, as shown in Fig. 4, comprises an outer element 50 in the form of an annulus, an intermediate annular element 51 and a cam plate `52, these elements being connected in coaxial relation by means of screws 53. Since the outer element 50 is xed to the stationary wall 4'7 of the box 12, it follows that the entire end member 49 remains stationary. An antifriction bearing 54 is mounted on the periphery of the intermediate element 51 and rotatably supports the end of the feeding sprocket 42, snap rings 55 being employed for retaining the drum axially in place. The central bearing 40 may be said to support the right-hand end of the electric motor 38 while permitting rotation of the feeding sprocket 42 with rcspect thereto. The shaft 56 of the electric motor 38 projects from the right-hand end of the casing 37 and is provided with a driving pinion 57 which is adapted to rotate the feeding sprocket 42 in the manner to be later explained. I

The inner surface of the feeding sprocket 42 is formed with gear teeth providing a rst orbit or ring gear element 60. Surrounding the cam plate 52 and rotatable thereon is a locking ring 61 which is formed with internal ygear teeth providing a second orbit or ring gearrelement 62. The cam plate 52 is providedon its periphery with a plurality of inclined recesses 64 in each of which is disposed a roller 65, the rollers being normally urged toward the shallower portions of the recesses by means of spring-actuated pins or plungers 66. Such an arrangement of parts is common in one-way clutches but in the present instance these parts together provide a free-wheeling locking means, it being noted that since the end member 49 is stationary, when the locking ring 61 is rotated to a slight extent in counterclockwise direction as viewed in Fig. 6, the rollers 65 move in the same direction in their respective recesses 64 and wedge firmly between the components 52 and 61 to lock the latter against rotation for the purpose to be later explained.

Disposed between the right-hand end of the motor casing 37 and the cam plate 52 and surrounding the gear 57 and shaft 56 is a cage or spider member 68 which comprises a pair of companion rings 69 and 70, riveted or otherwise secured together. At three equidistantly spaced points the rings 69 and 70 are provided with recesses in their contiguous faces, these recesses together forming openings 71, across which extend pins 72. Rotatable on the pins 72 are compound planetary gears 73 each of which comprises a pair of integral or connected gears 74 and 7S. The gears 74 are somewhat larger than the gears 75 and their teeth mesh with both the motor shaft gear or sun gear 57 and the l'irst ring gear element 60. The other gears 75 mesh only with the teeth of the second ring gear element 62 which, as shown in Fig. 5, is of somewhat smaller diameter and has fewer teeth than the first ring gear element 60.

The end member 49 has an inner, axial bore 78 and an outer counterbore 79, the right-hand end of the motor shaft 56 extending into the bore, as shown in Fig. 4.

' Disposed within the bore 78 and having limited rotation therein is an anti-rollback clutch which has a ange 81 positioned within the counterbore 79. The clutch 80 carries three pins 82 which project from its inner face and on which are rotatably mounted clutch rollers 83, the axial holes of the rollers being somewhat larger than the diameters of their pins so as to allow the rollers to oat thereon. The axial bore of the cam plate 52 is provided with three inclined cam surfaces along which the rollers 83 are adapted to roll. i

Itis thus seen that when shaft 56 commences to rotate in a clockwise direction, as viewed in Fig. 6, and which would occur during a retrogressive movement of the ammunition belt, the rollers 83 are moved by a spring 8S in the same direction along the cam surfaces 85 so that, in effect, they wedge between these surfaces and the periphery of the motorshaft 56. The result of this action is to cause` the further clockwise rotation of the motor shaft to be promptly arrested, preventing rollback for the purpose to be later explained.

The coil spring 38 `coacts with the anti-rollback clutch 80 to produce this quick and elfective anti-rotational feature. The spring 88 is coiled around the barrel of the clutch 80 inwardly of the flange 81. One end of the coil spring engages in a hole in the stationary intermediate annulus 51 and the other end is secured to ange 81 by means of the end of a wire hook member 90 which extends through a hole in the ange 81 and'engages in an eyelet in vthe end of the coil spring 88. Hook 90 is disposed in a groove 91 which is cut into vthe external surface of the outer element 50. During assembly, this coil spring is given an initial preload under tension which serves to keep the parts of the inner cam mechanism in positive engagement at all times, thus eliminating backlash in the anti-rotational function.

As will be apparent from the foregoing, when the motor shaft 56 is gripped by the anti-rollback rollers 83 the shaft is prevented from rotating in a direction reverse to that in which it rotates to feed the ammunition belt 28 so that reverse rotation of the feeding sprocket 42 and retrogressive movement of the belt are prevented. However, it is frequently desired to unload the unused ammunition from the feeding track and the present invention provides means whereby the motor shaft 56 can be released to permit reverse rotation thereof. This means consists of the wire hook 90 which is adapted to be pulled outwardly by means of a loop 92 at its end. Since the hook 90 is connected to the clutch 80, outward movement of the hook causes the clutch to be turned in counterclockwise direction, as viewed in Fig. .6, so that the anti-rollback rollers 83 are revolved in a direction to release the shaft 56. This permits the feeding drum 42 to rotate in counterclockwise direction, as seen in Fig. 6, under the load of the ammunition belt so that the latter can move downwardly into the magazine 12, it

being understood that the electric motor 38 is at this time de-energized.

It is also desirable that the booster mechanism be free wheeling in the direction of feed so as to facilitate charging the gun, that is, to permit passing the leading end of the ammunition belt upwardly through the chute 13 and inserting it in the gun 10 while the belt is engaged by the sprocket 42 and the electric motor 38 is idle. To attach the ammunition belt 28 to the gun 10, the belt is merely threaded upwardly through the chute 13 and into the gun mechanism. To permit such movement of the belt 28, it is necessary that the sprocket drum 42 rotate clockwise, as viewed in Fig. 6, and this is made possible by the fact that the booster mechanism is free wheeling in the direction of normal feed. That is to say, when the booster motor is idle and the belt is pulled in a feeding direction, the compound planetary gears 74, 75 can rotate on their axes and revolve around the sun gear, carrying the locking ring 61 and internal gear 62 with them in a clockwise direction as shown in Fig. 6, thereby causing rollers 65 to move to the right, maintaining ring 6l in an unlocked condition. However, if during the threading of the belt upwardly through the chute the belt is inadvertently released by the gunner, reverse movement of the belt is prevented bythe wedging action ofr the anti-rollback rollers 83 between the cam faces 85 and the motor shaft 56 to check reverse or clockwise rotation Aof the latter which, in turn, vprevents reverse rotation of the planetary gears and the feeding sprocket 42.

It is desirable that the electric motor 38 of the booster mechanism 20 be cle-energized following each advance of the ammunition belt 28 between bursts of ring. Referring to Fig. 1, the present booster mechanism may include an electric switch 95, preferably of the microactuated type, which is mounted at the side of the chute 13A in a position wherein its actuator button may be engaged by a cartridge 25 or a link of the ammunition belt 28 when the same is flexed laterally within the chute.

That is to say, at the completion of a feedingstroke of the belt 28, the upper end thereof meets with resistance. with-iinthe gun 'andi the belt tends to. buckle slightly inthe lll chute. This buckling movement of the belt is kutilized to vopen the normally closed switch 95,'which is connected in the electric circuit for the booster motor 38, so as to de-energize the motor. By this means, energization of the booster motor 38 is permitted only when the gun recoil mechanism is active so that excessive buckling of the ammunition belt, which might result in damage to the belt, is avoided.

Assuming that the feeding mechanism of the gun is idle, as when a cartridge is being red or about to be red, the switch 95 is open so that the booster motor 38 is de-energized and thus the motor shaft 56 and its sun gear 57 are free to rotate in counterclockwise direction to rotate the sprocket 42 in feeding direction but prevented from rotating in clockwise direction by the antirollback rollers 83.l The recoil mechanism of the machine gun, indicated at 11 in Fig. l, acts in response to ring of a cartridge to take up the slack in the ammunition belt 28. During this straightening of the belt 28 by the mechanism 11 the switch 95 is permitted to close so that the boostermotor 38 is energized to effect rotation of the shaft-56 and sun gear 57 in counterclockwise direction, as viewed in Figs. 5 and 6. Rotation of the drivf ing gear 57 in counterclockwise direction causes the compound planetary `gears 74, 75 to rotate in clockwise direction on their axes 72. As previously explained, the planetary gears 74 mesh with the internal gear 60 of the feeding sprocket 42, the other planetary gearsmeshing with thefinternal gear 62 of the locking ring 61. At the start of rotation of the gears 74, 75 in clockwise direction, these gears exert a thrust against the gear 62 in a counterclockwise direction to cause the clutch rollers 65 to wedge between the gear 62 and the fixed cam plate 52. The result of this action is to cause the gears 74, 75 to revolve in counterclockwise direction in an orbit concentric with the axis of the sun gear 57. This action causes the locking ring 61 to be promptly locked to the stationary cam plate 52 by the rollers 65. At this juncture, the ammunition beltv28 starts its feeding motion upwardly through the chute 13 to the automatic gun 18 and this is accomplished by rotating the feeding sprocket 42 in clockwise direction as viewed in Figs. l, 5 and 6 (counterclockwise in Fig. 3). Since the internal gear 62 is at this time locked against rotation, the several rotating-compound gears 74, 75 roll aroundthis internal gear and, because the sprocket .42 and its gear 60 are now free to rotate, the gears 74, 75 impart rotation thereto and this is due to the fact that in completing a full revolution about the sun gear 57 the gears .74 make a full number of revolutions abouty their own axes 72 plus a fraction of another such revolution. vInl other words, the gear 60 has a few more teeth than the now stationary gear 62 and the ratio between the gear 60 and the gears 74 is such-that the latter not only revolve around the gear 60 but, during each such revolution, advance the driven gear 60 through the distance of a few teeth. Thus the feeding sprocket 42 is rotated at a slow rate of speed from the electric motor 38 commensurate with the rate of ring of the gun 10, the ratio of speed being dependent upon the relative sizes of the' various gears. As an example, thegear 57 may have nine teeth and may rotate at 12,000 R. P. M., the' gears 74 may have twenty teeth, the gears 75 seventeen teeth, theinternal gear 62 forty-eight teeth and the internal gear 60 fifty-one teeth, such a gear ratio causing the feedingsprocket 42 to rotate at one-seventieth the speed of the motor shaft 56, or 171.5 R. P. M.

If the feeding sprocket 42 is rotated in the manner explained above, the ammunition belt 28 is fed thereby laterally and upwardly .through the chute 13. By the arrangement of the reduction gearing above described, torque of considerable rnagnitudeis` applied to the feeding sprocket 42 to overcome frictionalresistance to the feeding movement of the belt 284 and the'gravitational pull thereon so that thebelt is positively fed tothe gun at the rate of travel required to maintain `rapid `tiring of the gun. `The feeding of the ammunition to the gun may be substantially continuous and continues until the movement of the belt is 4resisted as, for example, when operation of the firing mechanism llof the gun `is discontinued. At this time, the advancement of the belt 28 is checked so that rotation of the feeding sprocket 42 is arrested.

Substantially simultaneously with` or just prior to the arresti-nent of the `feeding of the belt 28, the latter tends to ex laterally within the chute 13 so that one of its links engages the actuator button of the switch 95 to open the same. By this action, the circuitto the electric motor 38 is opened to cle-energize the motor. As will be apparent, when the rotation of the sprocket 42 is arrested, and the locking ring 61 remains locked, rotation of the compound planetary gears 74, 75 is impossible so that the motor shaft 56 is immediately brought to rest. Immediately the shaft 56 is stopped, the anti-rollback rollers 83 Wedge between the cam recesses 85 and the shaft 56 whereby` to prevent reverse rotation thereof. Since the booster device is thus brought to restand locked against reverse rotation while Athe ammunition belt 28 is in its advanced position, retrogressive movement of the belt which would result in slackness thereof is positively prevented. Due to this provision, the imposition of strain on the parts of the gun mechanism 11 or those of the booster device is avoided and a positive control of the ammunition is assured at all times.

After the leading cartridge 25, advanced by the feeding action explained above, is subsequently red in the gun 10, the recoil resulting fromsuch tiring acts to initially draw the ammunition belt 28 upwardly. This action straightens the belt by taking up any advance slack therein so that the actuator button of the switch 95 is released by the belt to `effect closing of the motor circuit. Upon energization of the motor 3S, torque developed by its shaft 56 is immediately transmitted through the gears 57, 74, 75, 62 and 60` to rotate the feeding sprocket 42 in clockwise direction (Fig. 6) so as to again feed the belt 2S through the distance necessary to position succeeding cartridges in the gun for firing in the manner" previously explained. While it may appear from the foregoing that the ammunition belt 28 is advanced with a step-by-step motion between tiring of successive cartridges `by the gun 10 and that the action of the booster mechanism 20 is thus intermittent, it will be readily apparent that the rate of tiring of` such automatic guns is rapid and` takes place before the belt can exfin the chute 13 sufficiently to open the switch 95 so that the operation of the booster mechanism is substantially continuous until the firing ceases.

It is apparent from the foregoing that the present booster device functions with great precision and at a speed commensurate with the operational speed of the gun. As pointed out, the booster feeds the ammunition belt only through the `required distance so that undue strain on the gun parts, the belt and the elements of the `booster is avoided and it is unnecessary to employ `a slip clutch ratchet or other equivalent'means such as is commonly used in boosters of `this general type. Moreover, considerable torque is applied to the feeding sprocket at a substantial distance from the axis of the prime mover, so that a smaller motor than heretofore employed for a like purpose can be utilized. Furthermore, the present booster is self-locking following advancement of the ammunition belt so that reverse operation and retrogressive movement 0f the belt due to the weight thereof, which would result in slackness in the belt and uneven feeding thereof, is positively prevented and it is unnecessary to provide means for compensating for such reverse movement of the belt. yThrough the use of my improved booster, it is possible to operate the machine gun at a substantially faster rate and, in addition, the booster decreases-failures of the ring mechanism in battle.

In 'the present improved booster mechanism the motor assembly whichis directly connected to the booster mounting, drives a compound planetary gear train. Drive in thedirection of feed is accomplished through the differential `of the ring gearst and 62. The internal drive gear 60, Iintegral with the drum 42, drives `through this differential as` initial motionof the gear traincauses the internal orbit gear 62: to become mechanically locked by theV action of the free-Wheeling clutch 64, 65, which is directly connected towthe .booster end cap 49. The full torque reaction of driving the booster is delivered to themounting cap 49 on the drive end by the action of theinternal gear 62.1ocking to the clutch cam 52. The torque reaction at themotor `end of the booster can be considered as negligible since only low motor torque is transmitted` at this point. .i

High efliciency gearing permits `reversibility of the gear train of the booster drum 42 in a direction opposite to drive. As the booster drum 42 is rotated opposite to the direction of drive,` the two internal gears 6i) and 62 rotate together, with slight differential, and the internal gear62 becomes unlocked from the free-wheeling clutch due to this reverse rotation.

To `accomplish anti-rotation" of the booster under load conditions, the motor pinion shaft 56 is extended through the gear train to engage with the anti-rotation release cam rolls 83 `associated with the inner cam surfaces 85 of `the anti-rollback `clutch 80. Under load the motor pinion 57 would normally rotate opposite to the direction of .drive due to the reversibility of the gear train. To prevent this, :the initial rotation of the motor pinion 57 `causes the extended shaft 56 to moveV the rolls S3 against the inner cam surfaces 85 and thus lock the motor armature. The clutch S0 `is provided with the torsion spring 88 to assure positive engagement of the inner cam mechanism, `thus preventing backlash in the booster drum. Turning the anti-rollback clutch 30 through a small angle in `a driving direction unlocks the motor pinion' 57 and permits unloading of ammunition over the booster.

I claim as my invention:

1. Ina booster device of the character described, the combination` of: a tubular, rotatable sprocket member provided with a first internal gear; an electric motor disposed within said sprocket member and Xedly mounted so that said sprocket member can rotate therearound, said motor having a shaft;` a sun gear on said shaft and rotated by said motor and disposed coaxially with said sprocketmember; a cage member rotatable about said sun gear; at least one compound planetary gear rotatable on said cage member and including a first planetary gear meshing with said sun gear and said rst internal gear, and a second planetary gear; a second internal gear member rotatable within said sprocket member, said second planetary gear `meshing with said second internal gear member; and locking means adapted to engage with said second internal gear member to prevent rotation thereof, said compound `planetary gear being adapted, when said second internal t gear is locked against rotation, to revolve around said second internal gear member and said sun gear and to thereby transmit rotation to said sprocket member from said sun gear at a reduced rate of speed. i

2. A booster device of the character defined in claim 1 in which said second internal gear member is formed integrally with a locking ring, and in whichsaid locking means includes a stationary cam member disposed coaxially of said locking ring, said cam member having at least one inclined recess in its` periphery, and a springt actuated` roller `in said recess operable, upon rotation of said locking ring in one direction, to engage between said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction., r `3. A booster device as defined in claim 1 in Whic 9 said first planetary gear has a greater number of teeth than said second planetary gear and said sun gear, and said first internal gear has :t greater number of teeth than said second internal gear member.

4. A booster device of the character defined in claim 1 in which said second internal gear member is formed integrally with a locking ring, and in which said locking means includes a stationary cam member disposed coaxially of said locking ring, said cam member having lat least one inclined recess in its periphery, and a springactuated roller in said recess operable, upon rotation of said locking ring in one direction, to engage between said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction, said second internal gear member being adapted, when rotation of said first internal gear is stopped, to prevent revolution of said compound planetary gear around said sun gear so as to stop the rotation of said motor shaft.

5. A booster device of the character defined in claim 1 in which said second internal gear member is formed integrally with a locking ring, and in which said locking means includes a stationary cam member disposed coaxially of said locking ring, said cam member having at least one inclined recess in its periphery, and a springactuated roller in said recess operable, upon rotation of said locking ring in one direction, to engage between said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction, said second internal gear member being adapted, when rotation of said first internal gear is stopped, to prevent revolution of said compound planetary gear around said sun gear so as to stop the rotation of said motor shaft, said booster device also including anti-rollback means operative to prevent rotation of said sun gear in reverse direction.

6. A booster device of the character defined in claim 1 in which said second internal gear member is formed integrally with a locking ring, and in which said locking means includes a stationary cam member disposed coaxially of said locking ring, said cam member having at least one inclined recess in its periphery, and a springactuated roller in said recess operable, upon rotation of said locking ring in one direction, to engage between said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction, said second internal gear member being adapted, when rotation of said first inernal gear is stopped, to prevent revolution of said compound planetary gear around said sun gear so as to stop the rotation of said motor shaft, said booster device also including spring-actuated anti-rollback means operative to normally stop the rotation of said sun gear in reverse direction.

7. A booster device of the character defined in claim 1 in which said second internal gear member is formed integrally with a locking ring, and in which said locking means includes a stationary cam member disposed coaxially of said locking ring, said cam member having at least one inclined recess in its periphery, and a springactuated roller in said recess operable, upon rotation of said locking ring in one direction, to engage between said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction, said second internal gear member being adapted, when rotation of said first internal gear is stopped, to prevent revolution of said compound planetary gear around said sun gear so as to stop the rotation of said motor shaft in feeding direction, said booster device also including spring-actuated, clutch means engageable with said motor shaft and operative to prevent rotation of said shaft in reverse direction.

8. A booster device of the character defined in claim l in which said second internal gear member is formed integrally with a locking ring, and in which said locking means includes a stationaryfcam memberdisposed co`- axially of said locking ring, said cam member having at least one inclined recess in its periphery, and ra springactuated roller in said recess operable, upon rotation of saidI locking ring in one direction, to engage between said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction, said second internal gear member being adapted, when rotation of said first internal gear is stopped, to prevent revolution of said compound planetary gear around said sun gear so as to stop the rotation of said motor shaft in feeding direction, said cam being provided with at least one eccentric clutch face on its interior, said booster device also including: a clutch member coaxial with said motor shaft and rotatable with respect thereto; at least one roller oatingly mounted on said clutch member and disposed between said motor shaft and said clutch face, rotation of said motor shaft in feeding direction serving to displace said roller along said eccentric clutch face to withhold said roller from locking engagement with said shaft; and spring means operative in response to stopping of said shaft, to rotate said roller in a direction to cause it to wedge between said clutch face and said shaft so as to prevent reverse rotation of said shaft.

9. A booster device of the character defined in claim 1 in which said second internal'gear member is formed integrally with a locking ring, and in which said locking means includes a stationary cam member disposed coaxially of said locking ring, said cam member having at least one inclined recess in its periphery, and a. springactuated roller in said recess operable, upon rotation of said locking ring in one direction, to engage between Said cam member and said locking ring so as to lock said second internal gear member against further rotation in said one direction, said second internal gear member being adapted, when rotation ofsaid first internal gear is stopped, to prevent revolution of said compound gear around said sun gear so as to stop the rotation of said motor shaft in feeding direction, said cam member being provided with at least one eccentric clutch face on its interior, said booster device also including: a clutch member coaxial with said motor shaft and rotatable with respect thereto; at least one roller oatingly mounted on said clutch member and disposed between said motor shaft and said clutch face, rotation of said motor shaft in feeding direction serving to displace said roller along said eccentric clutch face to withhold said roller from locking engagement with said shaft; a spring connected between said cam member and said clutch member and having an inherent force slightly less than the full torque developed by said motor shaft during normal operation of said booster mechanism, reduction in said torque below said inherent force allowing said spring to move said roller into wedging engagement between said clutch face and said shaft so as to prevent reverse rotation of said shaft; and manually controlled means for rotating said clutch member in a direction to release said roller from wedging engagement so as to allow reverse rotation of said motor shaft. i v

l0. In a booster device adapted to feed an ammunition belt to the mechanism of an automatic gun, the combination of: a rotatable sprocket member adapted when rotated in a feeding direction to feed said belt to the gun mechanism; an electric motor having a drive shaft; means for energizing and de-energizing said motor; a cornpound planetary gear system between said shaft and said sprocket member whereby rotation of said shaft in one direction effects rotation of said sprocket member in said feeding direction at a reduced speed, said planetary gear system including an orbit gear and a one-way locking means normally operative to withhold said orbit gear from rotation so as to allow transmission of the drive from said shaft to said sprocket member in said feeding direction when said motor is energized, said planet u wt u t 11 tary gear system being free wheeling in said feeding direction so as to allow rotation of said sprocket member in said feeding direction at all` times; and a one-way clutch means normally permitting rotation of said shaft in said one direction but adapted to engage said shaft, upon de-energization of said motor, to prevent rotation of said shaft in a direction reverse to said one direction.

11. An ammunition feed booster, comprising: a rotatable sprocket;ta drivngmotor having a shaft; transmission means for driving said sprocket from said shaft at reduced speed; a stationary cam member; clutch means between said sprocket and said cam member enabling overrunning rotation of said sprocket in a feed direction; and clutch means between said shaft and said cam member enabling rotation of said shaft in a feeding direction, but opposingtits rotation in a reversed direction.

l2. An ammunition feed booster, comprising: a rotatable sprocket; a driving motor having a shaft; a differential planetary transmission driven from said shaft and including first and second rotatably mounted orbit members, one of said members being connected with said sprocket and initially being held against rotation by the load on said sprocket, whereupon rotational movement is transmitted to said other orbit member from said shaft; and means activated by the initial movement of said other member for locking it against continued movement in the same direction, whereupon rotational movement is now transmitted to said one of said members to drive the sprocket.

13. An ammunition feed booster, comprising: a rotatable sprocket; a driving motor having a shaft; a stationary member; transmission means for driving said sprocket from said shaft at reduced speed including a first clutch member supported for movement to clutched and non-clutched positions with respect to said stationary member, and in the non-clutched position enabling overrunning rotation of said sprocket in a feeding direction; a second clutch with a roller engaging said shaft, said roller being supported for movement to clutched and non-clutched positions with respect to said stationary member, said second clutch roller being actuatable to non-clutched position in response to rotation of said shaft in a feeding direction; and means normally biasing said clutch roller to a clutched position in which reversed rotation of said shaft is opposed.

14. An ammunition feed booster, comprising: a rotatable sprocket; a driving motor having a shaft; a stationary member; transmission means for driving Said sprocket: from said shaft at reduced speed including a irst clutch member supported for movement to clutched and non-clutched positions with respect to said stationary member, and in the non-clutched position enabling over-running rotation of said sprocket in a feeding direction; a second clutch with a roller engaging said shaft, said roller being supported for movement to clutched and non-clutched positions with respect to said stationary member, said second clutch roller being actuatable to nonclutched position in response to rotation of said shaft in a feeding direction; means normally biasing said clutch roller to a clutched position in which reversed rotation of said shaft is opposed; and manually operable means for moving said roller to non-clutched position independently of the shaft rotation.

References Cited in the le of this patent UNITED STATES PATENTS 2,364,309 North Dec. 5, 1944 2,384,746 Holloway Sept. 11, 1945 2,403,170 Chapman et al. July 2, 1946 2,413,665 Trotter Dec. 3l, 1946 2,428,414 Elliott Oct. 7, 1947 2,436,404 Slate Feb. 24, 1948 2,456,618 Carless Dec. 2l, 1948 2,629,288 Jenssen Feb. 24, 1953 FOREIGN PATENTS 561,958 Great Britain June 12, 1944

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2364309 *12 May 19425 Dec 1944Boulton Aircraft LtdMeans for feeding ammunition belts to machine guns
US2384746 *15 Dec 194111 Sep 1945North American Aviation IncRecoil operated ammunition feed for machine guns
US2403170 *29 Nov 19412 Jul 1946North American Aviation IncAmmunition feed booster
US2413665 *13 Aug 194231 Dec 1946Bell Aircraft CorpMachine gun feed mechanism
US2428414 *13 Jun 19417 Oct 1947Glenn L Martin CoMachine gun feed
US2436404 *27 May 194224 Feb 1948Hughes Tool CoAmmunition booster for automatic guns
US2456618 *5 Oct 194421 Dec 1948Carless Lionel SAmmunition booster control
US2629289 *3 May 194524 Feb 1953Sperry CorpFire control apparatus for controlling the flight of missiles
GB561958A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4328737 *12 Jun 197811 May 1982General Electric CompanyAmmunition feeder for a gun
US5782157 *2 Apr 199721 Jul 1998Esco Electronics CompanyChuting assembly for ammunition magazine feed
US20070004967 *6 Sep 20064 Jan 2007Olympus CorporationEndoscope
Classifications
U.S. Classification89/33.5, 89/33.1, 89/33.16
International ClassificationF41A9/51, F41A9/00
Cooperative ClassificationF41A9/51
European ClassificationF41A9/51