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Publication numberUS2843021 A
Publication typeGrant
Publication date15 Jul 1958
Filing date1 Dec 1952
Priority date1 Dec 1952
Publication numberUS 2843021 A, US 2843021A, US-A-2843021, US2843021 A, US2843021A
InventorsChapman James E, Johnston Walter G
Original AssigneeGarrett Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Ammunition booster with torque limiting device
US 2843021 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

July 15, 1958 J. E. CHAPMAN arm.

AMMUNITION BOOSTER WITH TORQUE LIMITING DEVICE Filed Dec. 1, 1952 2 Sheets-Sheet 1 :m mm w N wE Z 0M 5 July 15, 1958 J. E. CYHAPMAN ET AL 2,343,021


Filed Dec. 1, 1952 2 Sheets-Sheet 2 Jwzs C/m wmtg Wu 7252 6. Jam/Ks rm;


V v the power'rneans' driving'jthe booster.

rates ITHON BGOSTER WITH TGRQUE LTINGDEVICE James E. Chapman, Los Angelesyand Walter G, Johnston, Culver City, Calif.,-assignors to'lhe Garrett Cerporation, Los Angeles, Calif.,"-a;corporation of Callorma Application December 1, 1952,1Serial No.\323;402 -s Claims. c1. sst-'33 The present invention relates. generally .to an ammunition feed booster forzaugmentingthewfeed of ammunition in the form of belts of linked cartridges, or-.other arv.rangements wherein the cartridges "areisuccessively fed to rapid fire guns, suchasmachine guns onthe'like;

It is one object of-the :herein'described inventionto g-provide an improved ammunition boosterwhichrincorporates novel means for utilizing :the torque reaction sforces or countertorque developed in the driving mechanism of the booster, by belt-feedingioperation, -for controlling the operation of thebooster driving power means so as to. stop the feed-of ammunition when-;the;gun stops .gfiring, or may'become jammed.

A further objectis to provide in -connection withflan ammunition feed booster,. uniquewmeans'associatedwith the moving cartridge belt for -positively controllingthe powcrmeans operation, sowas tostopthe power means -as the last cartridge'moves .oliithe"belt-.teeding:sprocket. "Another object of the invention resides ,inkthe .pro- =visin of a 'countertorque-device of suchcharacter that energy may bestoredfor utilizationwhen the; gun-starts to fire and the belt moves-forwardly in ;a; feeding direction, such energy being available :to applywa momentary impulse to the cartridge 'belt during the starting wmove- "ment thereof in advance of theactual-:energizationbf Still another iobject'of :the present. inventionristov provide unique anti-roll 'back release means:=-so asto permit "reversed rotation of the booster -fce'dqand"-thus-make it possible to Withdraw or -unload=theZ remaininghunfired portion ofan ammunition :belt?fromwthemhute in reverse' idirecti'on,

1' It--is also an pobject -sto provideemechanism,eof:gthe

--hereindes'cribedcharacter '';which is combined into ::a -compactunitary assembly ofisuch character that it: may

- be mountedwithinthe mechanism housing of the booster and thus protected against the. ravages? of weather; is'uch sas saltcspray, 'dust,whumidity, :etc. I I

"Briefly stated; the ammunitionwfeed, booster 4Of5flie present 1 invention compri-ses,-;initsbroadraspect, .power 'rme'ansarranged "to dr-ive ammunition rebelt feeding -;;sprockets through =a=transn1issi0n including inqthis i case planetary -;-gearing in which one driving-element, such as'an orbit orjring; gear isisupported. sod-that, duringthe :vfe'eding operation, thegear:'haswlimitedmiovement inone ment is determinedb ":the-:spring-;design;andithe:driving I-torque reaction force or. countertor quew developed rin the driving; means of: the tbooster. As the zload'increa'scs the -.-,driving elerne nt -,rnove s --t0 -=furtherenergize ithe=spring.

. -Advanta'gc; :isttaken-of this movemengt-thrqugh a Suitable motion transmitting? connection to actuate :a suitable, cam a or other meanst for deactivating the; powerqmeans, which :may, loci-accomplished in variousvwvays. Eor' example,

Q qthe cam may-'open a switch-inthe-energizing eircuitacf am electric motortpowermeans. j

utilization of torque reactiontmeans suchgas rbl ifl-Y *atentice V Eatented July 15, 1958 energized spring which maybeutilized to give an initial impulse to the ammunition feed belt, when the gun 'starts to fire, so as tostart the belt feedin advance ofactual delivery of power from thepowermeans.

'Further'objects of .the invention will in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon Referring to the accompanying drawings, whichiarefor illustrative purposes only: i t

Fig. 1 is an end elevational view of ad'ammunition feed booster embodying the,present invention, applied to a cartridge belt delivery chute, and having cutaway portions to illustrate details of certain parts ofthe control mechanism;

Fig. 2. is a longitudinal sectional-view of::the driving end of the booster, taken substantially on -line'-22of Fig. l;

Fig. 3 is a transverse. sectional view,-taken substantially on line -3:3 ofFig. 2;

Fig. 4 is a transverse sectional view, taken. substantially on line t-4 of Fig. 2; c

Fig. 5 is-anend view of the driving end of :the booster, as viewed substantially from line 5-5- of Fig.2, portions being cut away to disclose certain details of Iconstruction'of theanti-rollback release mechanism; and

Fig. 6 is a transverse sectional view, taken substantially'on line6-6 of :Fig. 2; and showing detailjs of the v booster is. associated.- -As shown,-, the cartridge :belt feed is in an upward direction through the -chute, and, -as -'-a consequence, rotation of theysprockets x11 and '12; -will be in a counterclockwisedirection during the :fe'eding operation.

' -Morespecifically,l,iasshown .in F-ig. -2, :the booster V mechanism'qis .supp0rted on a cradle .trame structure 15 having end ;-le gs .16 and e17. to whichwendycaps- 1-8 :and .19 .arerespectively secured ,inany appropriate ma-nner so as to -be retained againstsmovement. )These: end caps cooperatively form supports-for- .anti friction bearingsQZO ,andazlawhich .rotatably support ai tubular drumwfl having the sprockets 11 and '12 secured thereto for unitary rotation.

.T he tubular drum Q22 in the, portionLassociatediwith able . the sprockets- 11 andISlZ, forms a. housing ,for a power means,hshown,in thisicaseas comprising tric motor 23 lhavingwa sta tionary .frarne structu having a reduced, .endportion 25 {which supportaanother anti-friction bearing 26 which ifur ther cooperates-Jose :tatablyh support the...-tubu-lar -drum..'-22 at-this aend ofathe irnotor. The rotative structure ot the ,motor 23 .in cludes a stub. shaft 27 -,which carries v ansuitabledriving pinion 28 which: tforms thez sun gear of sa compoundgplanetary gear train, subsequently to be descri-beilby which, power 'is transmitted'fro-m vtheflpowerttneansao. drivewtheidrum 22and associated sprockets ,ll and .12 at redueed speed.

Adjacent the :drivinge'nd of the rnotorsfi,thendrum .22 is providedgwithwgear teeth-whichgcooperate to ,form' I agfirstaring,oraorbit {gear 2920f: the, planetary gear, ttain. Also rotatablygsupportediformelative rotatiqnwyithin the d u 2 yme si antt-t i we s sins a atubube brought out i lar member 31 which is formed with internal gear teeth so as to provide a second ring or orbit gear 32.

Surrounding the pinion 28, there is provided a conve'ntional. spider assembly 33 which rotatably supports a plurality of compound planet gears 3 each of which is rotatable on a pin 35. Each of the compound gears embodies a pair of integral or connected gears 36 and 37, the gear 36 being somewhat larger in this case than the gear 37.

As shown in Fig. 2, a cam member or element 33 surrounds the stub shaft 27 with its outer peripheral face adjacent the inner periphery of the tubular member 31, the periphery of the cam member being provided with a plurality of inclined recesses 35*, as shown in Fig. 3 in each of which is disposed a roller 40, the rollers being normally urged toward the shallower portions of the re cesses by means of spring actuated plungers it. These parts coact to form a one-way clutch which in this in-- stance forms a free-wheeling locking means between the cam member 38 and the tubular member 31 which carries the orbit gear 32. It will be noted that the tubular member 31, as viewed in Fig. 3, may be rotated freely in a counterclockwise direction, but when rotated rela tive to the cam member 38 in a clockwise direction will cause the rollers to move in the same direction in their respective recesses and firmly wedge between the tubular member 31 and the cam member 38 so as to lock these parts together for a purpose to be explained subsequently.

The compound planetary gear train and cam member 38, as thus far described, constitute an arrangement which is similar to the arrangement which has been fully disclosed and described in the copending application of James E. Chapman, Serial No. 74,972, filed February 7, 1949, and'now issued as Patent No. 2,757,576 covering Ammunition Feed Booster. In that arrangement, the cam member corresponding to the present member 38 was stationary, and under such circumstances, the operation of the planetary gear train was the same as in the present case, and briefly as follows: When the electric motojr'23 is energized, the shaft 27 and driving pinion '28 will rotate in a clockwise direction, as viewed in Fig. 3. At this time, the orbit gear 29 is initially stationary so that upon rotation of the pinion 28, the compound planet gears will be rotated about their respective" axes in a counterclockwise direction, and the compound gears caused to revolve in a clockwise direction in an orbit concentric with the axis of the sun gear or driving pinion 28. As a result of this movement, the compound planet gears exert a thrust against the orbit gear 32 in a direction to move the tubular member 31 clockwise and cause the rollers 40 to wedge between the tubular member 31 and the cam member 38. If the cam member 38 is now restrained against clockwise movement, the driving force will be transfererd to the orbit gear 29 and cause it to rotate in a counterclockwise feeding direction.

In the present invention, instead of having the cam member 38 anchored so as to be stationary, it is proposed to mount this cam member so that it will have limited movement and can move against an opposing biasing force under the effect of the torque reaction force or countertorque exerted upon the tubular member 31 during the feeding operation.

An arbor 42 having a tubular hub 43 and a radial end flange 44 is secured to the cam member 38 by means of a plurality of screws 45 which connect the flange portion and, support the tubular hub 43 so that it projects concentrically around the axis of rotation of the stub shaft 27. A cupped member 46 is supported by screws 47 from the stationary end cap 19, and cooperates with the tubular hub 43 and radial end flange 44 to provide an annular concentric housing for a coiled 'spring 48, one end of which is secured by an anchor pin 49 at one end to the stationary member 46, and at its other'end to the tubular hub 43. As shown in Fig. 4,

- frame.

point 74, the cam radius is of constant value.

the hub 43 is provided with a longitudinally extending slot 50 within which the inner end of the spring is anchored by folding the end of the spring back upon itself as shown at 51, this folded portion being inserted in the slot and held therein by the overlying conv-olutions of the spring. With the arrangement just described, it will be apparent that the limited movement of the cam member in a clockwise direction will have the effect of winding up this spring which will thus act to oppose the cam rotational movement in a clockwise direction, but permit the cam to move a greater or less amount depending upon the torque reaction forces, for a purpose which will subsequently be explained more fully.

Within the tubular hub 43 of the arbor 42, there is positioned a cylindrical anti-rollback clutch which comprises an elongate cam member 52 having an enlarged head portion 53 containing an end opening socket 54 adapted to receive the end of the stub shaft 27 therein and rotatably support this end of the cam member. The head portion carries a plurality of pins 55, in this case three, which project from its inner face and on which are rotatably mounted clutch rollers 56. These rollers are respectively associated with inclined cam surfaces 57 at the inner periphery of cam member 38, and along which the rollers 56 are adapted to roll. The rollers are also in contact with the outer surface of stub shaft 27. With this arrangement, it will be noted by reference to Fig. 3, that during normal drive in which the shaft 27 rotates clockwise, the rollers will be movedto a position which will enable free rotation of the shaft 27 in a driving direction. However, in the event that the shaft 27 should be rotated in a reversed direction, which would occur during retrogressive movement of the ammunition belt, the rollers 56 are moved by the action of a spring 53, which interconnects the hub 43 and cam member 52, in a direction along the cam surfaces 57 such that they wedge between these surfaces and the periphery of the motor shaft. Reverse movement of the shaft will initially move the cam member 38 in a reversed direction which will tend to unwind the spring 48. This being a heavy spring, the member 38 will only move a slight distance before it acts to prevent reversed movement of the shaft, or anti-rollback. However, the rollers may be released to permit removing a belt in a reversed direction, when necessary, as will later be described.

The opposite end of the cam member 52 carries a shaft extension 59 which projects through an opening 60 in the end cap 19. Adjacent the outer end of the shaft extension 59, a pulley 61 is supported for free rotation and retained against removal by a snap ring 62. Provision is made for rotating the pulley 61 in a clockwise direction by means of a flexible cable 63 which has one end carried over a portion of the grooved periphery of the pulley, this end being anchored by an anchor member 64- which is positioned ina peripheral slot 65 of the pulley. The other end of the cable is carried through a conduit 66 to a convenient point where the operator may man- .ually pull the cable to turn the pulley. Rotation of the pulley in a clockwise direction is opposed by the action of a coiled spring 67, one end of this spring being anchored as shown at 68 to the end leg 17 of the cradle The other end of the spring is provided with a hook 69 which is connected with the bottom of the pulley groove adjacent the anchor member 64.

Betweenthe pulley 61 and the outer face of end cap 19, a cammember 70 is connected to the shaft extension 59, as by a splined connection or other means. As shown in Fig. 6, the cam 70 is illustrated as having a cam lobe 71 which extends from a point 72 of minimum throw to a point 73 of maximum throw. From point 73 to a At the point" 74, the cam lobe terminates in an end shoulder 75 which is disposed in the path of movement of a pin 76 carried by the pulley 61. With this arrangement, it will be seen that, although the pulley is freely rotatable on actuate the contacts to their open position.

the shaft 59, rotation of the pulley will actuate the shaft 59'with a rotative movement by acting through-the cam member 70.. Thus, rotation of the shaft 59in a clockwise direction'will operate to move the clutch rollers 56 to a *releasedpositionwith respect'to the motordriving stub shaft27 so as to permit 'retrogressive movement of the'ammunition belt, when necessary, as previously .ex-

plained. a

Referring again to Fig. 6, a 'cam follower lever 77 is supported on a pivot '78'for rocking movements. One endof'the lever is associated with the cam 70 while the other end is associated with aswitch button 79 for operating normally closed contacts of switch assembly 80 to open position, when the'button 79"isdepressed. 'The follower lever is normally biased in a clockwise direction by a spring 81. Theswitch' 80 and associated follower lever are supportedas a unit' fromthe 'cradle'f-rame 15 g by means of suitable mounting bolts-82.

The contacts of switch assembly '80 are utilized'for controlling'deactivation of the power means upon the .occurrence of'a torque'reaction force or countertorque above a predetermined value. Under normal operating 'reactionforces. Thus, it will be appreciated that movement of the cam '70 sufliciently to actuate the switch contacts 'will depend upon the design of thespring 48 which biases the clockwise movement of the cam member 38 under the torque reaction force, as'previously explained.

More specifically, the cam 70' is so positioned on'the shaftextension 59 that the point- 73 will have moved to a position which'will open the contacts of switch 80,

iwhen thei torque'reaction force reaches a predetermined value. "As anexample, let it:be'assumed that it is desired to deactivate the power means when thetorque reaction force corresponds to theapplication of a cartridge or ammunition belt weight of 90 pounds upon the sprockets 11 and 12. The cam 70 may be adjusted by applying the desiredweight to. the sprockets 11 andr12. This will act to turn the .hub..43..and..thus wind. the spring 48, movement of hub 43...acting.throughbspring. 58 tov carrythe shaft 59 with it, aspreviously explained, to a corresponding position inaccordance with: the applied weight. The point'73 is then-positioned, in contact with the associated end of the cam follower lever, thus acting to swing it counterclockwise to its extreme position of movement. The switch 80 is then adjusted so that at this position of the cam follower, the button 79 will be in a position to With this adjustment, the power means will be deactivated whenever the torque corresponding with the 90 pound ammunition belt weight occurs. It will be apparent that the cam may be further moved from point 73 to point 74 so as to release the anti-rollback mechanism, without affecting the operation of the switch 80.

The operation of the switch 80 by the movement'of cam 70 is also used for controlling the booster in response to stoppage and starting of the belt feed at the gun. For example, when the gun stops firing, movement of the belt at the gun stops. However, the booster motor continues to run and drive the belt,-with the result that the torque reaction forces cause the spring 48 to wind up further and at the same time move the cam 70 to a position in which the contacts of switch 80 are opened, whereupon the booster stops with the spring 48 in a stressed condition. Upon resumption of gun firing, the

belt is released at the gun for feeding movement. The stressed spring 48 now acts togive the belt a momentary kick or initial impulse which starts boosting the belt feed in advance of actual delivery of power from the, booster, motor. As soon as the belt feed is started by the gun and with the assistance of the spring 4 8,,the;carn,70

moves to.a point where it closes the contactsof switch to activate'the. booster motor.

For controlling the deactivation of the power means,

a. suitable spring 86; As shown, 'the free end of' the door is curved: so thatwhen a belt -isinithe chute1'3, the

advancing cartridges willride over the; doorand hold it in the position shown.

Adjacent the hinged end of' the door, the door isprovided with a'projection 87 which is cooperatively associated' with a switch button- 88 for controlling normally open contacts of a switch 'mechanism'8-9; this mechanism being supported from the -cradle'frame 15 by suitable bolts- 90. Witha belt-cartridge, as shown indotted lines and indicated by the numeral 1-4, holding the trap door 84' in-the position shown, the contacts of switch mechanism 89 will, be maintained in closed position. However, when the last cartridge has moved through the chute to a position permitting closure-of the trap door by swinging in a counterclockwise direction, the switch button 88 will move outwardly so as to open the switch contacts. By placing these-contacts in'a suitable control circuit'for the-power means, the power means may be deactivated as the last cartridge leavesthe feed sprockets.

Various modifications may suggest'thems'elves' to those skilled; in the art without departing from the spirit of our invention, and hence wedo not wishto be restricted to thespecific form shown or uses'mentione'd except to the extent indicated in the appended. claims.

We claim:

1. An ammunition feed booster, comprising: a rotatable sprocket; a drivingmotor having ashaftand an energizing circuit; an 'elementresiliently biased against movement in one direction; transmission means for driving said sprocket and element from said shaft at reducedspeed including a first clutch member movable. to clutched and non-clutched: positions with: respect: to :said element,

and in -thenon=c1utched;v position enabling over-running tion of said shaft in a feeding direction, but in clutched position opposing its rotation in a reversed direction; means normally biasing said second clutch member toward clutched position; a cam connected for movement with said second clutch member in response to movements of said element; means for controlling said energizing circuit including contacts actuated by said cam; and means including said cam for manually moving said second clutch member to non-clutched position.

2. An ammunition feed booster, comprising: a rotatable sprocket; a driving motor having a shaft and an energizing circuit; an element resiliently biased against movement in one direction; transmission means for driving said sprocket and element from said shaft at reduced speed including a first clutch member movable to clutched and non-clutched positions with respect to said element, and in the non-clutched position enabling over-running rotation of said sprocket in a feeding direction; a second clutch member associated with said shaft movable t0 clutched and non-clutched positions with respect to said element, and in the non-clutched position enabling'rotation of said shaft in a feeding directidnybut in clutched position opposing its rotation in a reversed direction;

with said second clutch member in response to movements of said element; and means for controlling said energizing circuit including contacts actuated by said cam.

3. ,An ammunition feed booster, comprising: a cartridge moving member; a driving motor having a shaft and an energizing circuit; a differential planetary transmission driven from said shaft and including first and second rotatably mounted orbit gears, the first of said gears being connected with said member and initially held against rotation by the load on said member, whereupon rotational movement is transmitted to said second gear; a rotatable member; means biasing said rotatable member against rotation in one direction; means activated by the initial movement ofsaid second gear for drivingly connecting it with said rotatable member, whereupon further continued movement of said second gear in the same direction is opposed and terminated by said biasing means depending upon driving torque reaction forces and rotational movement transferred to said first gear to drive the cartridge moving member; and means for controlling said motor including contacts in said circuit having an operating connection with said second gear.

4. An ammunition feed booster, comprising: a cartridge moving member; driving power means having a shaft; a differential planetary transmission driven from said shaft and including first and second rotatably mounted orbit gears, the first of said gears being connected with said member and initially held against rotation by the load on said member, whereupon rotational movement is transmitted to said second gear to drive it in one direction; spring means having a connection with said second gear for resiliently opposing and terminating its rotation in said one direction in accordance with driving torque reaction forces, whereupon rotational movement is transmitted to said first gear to drive the cartridge moving member; and means having an operating connection with said second gear for deactivating said power means in response to a predetermined movement of said second gear.

5. An ammunition feed booster, comprising: power means; ammunition feeding means driven by said power means and including a planetary transmission having a rotatably mounted orbit gear; means for biasing said orbit gear, said means including a spring and limiting movement of said gear upon its being rotated a predetermined extent in one direction under torque reaction forces; and means actuated in response to a further movement of said orbit gear in said one direction under a predetermined increase of the torque reaction forces for deactivating said power means.

6. An ammunition feed booster, comprising: power means; ammunition feeding means including a cartridge advancing sprocket driven by said power means; a gear connected with said feeding means, said gear being movable in one direction by torque reaction forces set up in said sprocket during cartridge feed; a spring actuated by said movement and energized in accordance with said torque reaction force to oppose and limit said gear movement; and means actuated in response to a predetermined movement of said gear for deactivating said power means.

7. An ammunition feed booster, comprising: a chute for feeding cartridges to a position of use, said chute having an opening therein; electro-magnetically driven means having axially spaced sprockets extending into the chute for advancing said cartridges therein, including an energizing circuit; a hinged closure for said opening positioned between said sprockets and having a portion adapted to swing in one direction into said chute, in the absence of advancing cartridges, to one position in the line of travel of cartridges therein, but .being moved in an opposite direction by advancing cartridges to another position; and means for controlling said circuit including a switch actuated by movements of said closure to said positions.

8. An ammunition feed booster, comprising: a chute; electric-magnetic power means having an energizing circuit; means actuated by said power means for advancing cartridges along said chute in a feeding direction; means for controlling said circuit including a switch; and an actuating member for said switch extending into said chute in the line of movement of said cartridges, said member acting to maintain said switch in one position of operation so long as it is engaged by advancing cartridges, but operating to actuate said switch to another position of operation upon advancement of the last cartridge out of engagement with said member.

References Cited in the file of this patent UNITED STATES PATENTS 2,390,401 Trotter Dec. 4, 1945 2,403,170 Chapman July 2, 1946 2,436,404 Slate Feb. 24, 1948 2,456,618 Carless Dec. 21, 1948 2,557,441 Kornblum June 19, 1951 2,617,330 Pataki Nov. 11, 1952

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2390401 *16 Mar 19424 Dec 1945Bell Aircraft CorpOrdnance
US2403170 *29 Nov 19412 Jul 1946North American Aviation IncAmmunition feed booster
US2436404 *27 May 194224 Feb 1948Hughes Tool CoAmmunition booster for automatic guns
US2456618 *5 Oct 194421 Dec 1948Carless Lionel SAmmunition booster control
US2557441 *1 May 194419 Jun 1951Harvey Machine Co IncFeed for guns or the like
US2617330 *10 Mar 194811 Nov 1952Reconstruction Finance CorpAmmunition booster
U.S. Classification89/33.5, 477/11
International ClassificationF41A9/51, F41A9/00
Cooperative ClassificationF41A9/51
European ClassificationF41A9/51