US2821888A - Belt feed mechanisms for automatic firearms - Google Patents

Description

B. MAILLARD 2,821,888

BELT FEED uEcHANIsMs FOR AUTOMATIC FIREARMS original Filed Maren 25. 1952 Feb. 4, 1958 4 Sheets-Sheet 1 IlIl .lllllllllP-IILIIIrIllI.-

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Feb. 4, 1958 f B. MAILLARD i BELT FEED MECHANISMS FOR AUTOMATI'C FIREARMS Original Filed March 25, 1952 E 4 Sheqsizs--Sheei'l 2 B. MAILLARD BELT FEED MEcHANrsMs Fon AUTOMATIC FIREARMS. f original Filed urch 25, 1952 Feb. 4, 1958 .4 Sheets-Sheet 5 ww .m mi w QM.

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Feb. 4, B. MAILLARD BELT FEED MEcHANrsMs FOR AUTOMATIC FIREARMS /riginal Filed March 25, 1952` 4 sheets-sheet 4 BELT FEED MECHANISMS FOR AUTOMATIC FIREARMS Bernard Maillard, Geneva, Switzerland Original application March 25, 1952, Serial No. 278,349,

now Patent No. 2,750,845, dated June 19, 1956. Di-

vided and this application May 4, 1956, Serial No. 582,870

claims priority, application Luxembourg Maron 21, 1951 s claims. (ci. ssi- 33) The present application, which is a divisionl of my prior application Ser. No. 278,349, filed March 25, 1952, now Pat. No. 2,750,845, relates to belt feed mechanisms for automatic firearms to which ammunition is fed in the form of cartridge belts. The term belt feed mechanism is meantto include any mechanism capable of moving toward the firearm the cartridges assembled together to form a belt and of feeding them successively thereto during firing. My invention is more especially, but not exclusively, concerned with firearms the breechblock of which is released through means other than the recoil of the arm, for instance by a gas tap.

The object of my invention is to provide a firearm of this kind whichis better adapted to meet the requirements of practice `than those existing at the present time.

For this purpose, according to my invention, a first element, actuated by a power device supplying a power impulse of an=amplitude corresponding to one pitch (distance by which the belt is to be moved forwardV for every shot) every time a shot is fired, is connected with asecond element, or rotor, which drives the belt step by step and in which the successive cartridges are detached from the belt, the transmission system between said first and second elements being arranged to provide for a limited lost4 motion opposed by resilient means, the amplitude of said lostmotion being less than the amplitude of movement of said second `mentioned element for every step thereof, the amplitude of said lost motion and the means for passing the cartridges detached from the belt to4 the firearm breech case being adjusted to preventany contact between said second mentioned element and a cartridge stopped in waiting position before introduction into the firearm barrel when said resilient means are eliminating said lost motion at the end of every step of Fig. 1l is a perspective view showing the essential ele' ments of the belt feed mechanism, separately from the other parts.

The firearm with which my invention is concerned includes a barrel 1 rigid at the rear with the breech case 2 in which reciprocates a breech block 3 urged frontwardly by a recuperator spring 4 and controlled, concerning its release, by a gas tap system S.

The whole of these elements, which constitutes the firearm proper, vis slidable in a fixed support or cradle 6, an elastic system 7 being interposed to absorb the recoil of the firearm with respect to its support and to return it frontwardly.

Rigid with support 6 there is provided a plate 8 (magazine carrier) intended to receive the belt feed mechanism 9 which will be hereinafter described. For instance, as shown, this plate 8 is linked to support 6 by an arm 10 and the upper edge of the breech case slides on the under face of said plate vduring the reciprocating movements of the displacement of the firearm proper during a portion (hereinafter called active portion) of its recoil with respect to support 6, this displacement being imparte-d to `the belt through a transmission which will now be desaid second mentioned element, whereby such a cartridge in waiting position is not subjected to a thrust from said resilient means.

`Other features of my invention will become apparent in the course of the following detailed description of an i AFig. 7 `is a sectional view on the line VII-VII of Fig. 9;

AFig 8 shows a detailof Fig. 4;

Fig. 9 is a vertical view a portion of which showsl a section on the line IXa-lXa of Fig. 2 and another portion a section on the line IXb-IXb of Fig. 2;

Fig. l0 is a horizontal view a portion of which shows vtixra section on the line Xb-Xb of Fig. 2;

a gsection on`the line Xa--Xa of Fig. 2 and another porscribed. i

The belt feed mechanism 9 frame essentially includes of the firearm to rotate a shaft element 15 (Figs. 2, 3 v

10 and ll) parallel to the direction of fire, through a given angle every time a shot is fired, this shaft element 15 being journalled in said front plate 13.

This last mentioned mechanism includes the followingf elements (Figs. 2, 3 and 9):

Front plate 13 carries a vertically sliding member 16, urged downwardly by ,a spring 17 interposed between a horizontally projecting flange of member 16 and a horizontally projecting flange 13a of plate 13, this sliding member 16 carrying a spindle 18 parallel to shaft element 15 and on which a pinion 19 is freely journalled.

The front portion of the firearm breech casing carries, pivoted about a horizontal axis 21, a longitudinal arm 20 the rear end of which carries, projecting from its under face, a roller 22 arranged to cooperate with a ramp 23 advantageously carried by a plate 13 rigid with plate 13 and which forms the front wall of the belt feed mechaof the recoil stroke of the firearm, this sliding member 16 is pushed upwardly against the thrust of spring 17,

under the simultaneous effects of the upward movement of the rear end of arm 20 and of the slope of ramp 24,

which produces a supplementary upward movement of lelV thereto and freely journalled'in plates 13 and .13?, ,.I

Patented Feb. 4, 1958V place-.during .the :active portion of the. 4firearm Lrecoil, which portion 4isladvantageously limited.V4 to .that corre-- sponding to the minimum amplitude recoil.

. I will; now describe. :howf thisA movementis transmitted to the cartridge Adriving -means `of the'. belt. ieed; mechanism.' 44Said drivingmeans include-ashaftl 32 .(Fgs. 9, 10fl-and 11i) substantiallyparallel.-tov the Adirection of ringf-and journalledrin plates ...I3-and -14. This shaft carries, fixed thereon,.arplurality.of..(three in the ypresent Iexample) toothed wheels 32a which constitute what will-betv hereinaftencalled the rotor of! therbeltfeed mechanism. vThe teeth of. saidlrotort wheelsy arefarranged to engage Ibetween.4

the cartridgesof the belt,1 soas to" drivel` this belt. Shaft 32. is preferably positioned so IIthat the..cartridge .belt,.

which enters the mechanism horizontally, asfrshown :by Figs. -4, J5. iand` 6, nis... deected downwardly,;iat :about #90 to its:..1'nitialv direction, :toward the feed 1 or introduction passage :33: o'thetirearm;

Shafts-element 1'5 is;connected to 1sh'aft32L-asfollows:

:Ln-:a tubular :sleeve-534 (Fig. .10) fextending .between plates :i113 fand 14 .fand 'parallel itoshaft 32 vare mounted, in end to end relation to each other, two sleeves 351and 36'. (Figs. vlilarid' l1)' the respectiveen'ds of which' adjacent to' each" other` -are provided with'fcooperating dogs lorprojections S31-138 :suchfy lthat a lost motion,l or1 relative f angular displacement of a maximumamplitudeequalttofais possible between these 'said sleeves35 y"and Z36.

pinion 27, land therefore-rotated Atogether with shaft pinion 39 disposediclosetothefrear endtplatelli; this pinion i 39 bein gf'tixed f `on "a shaft element AV'40journlled in said plate 14. p

-I"interpose between v 'shaftelements "135 1wand 40, inside sleeves35 and"3`6, 'a torsion" spring -l41 initially. "stressed" so'that `it 'urges shaft-40 to rotate with respect to shaft 15r`nthe "same directionas 'said shaft 17'5 isitself driven byts'fpinion "27' during' lthe active l`portion of the recoil movementL fthe :firearm (this direction of ^rotation i is indicated' `on."'Fig. '11 by the'arrow adjacent to.. pinion I1" journal in plate '14, coaxiallywthshaft 32.5"( which is t'bular)"`a'pinion 42,'for instance identical'to "pinion 9,"thisY pinion 42 being xed in rotation on 'ai'shaft elment43.

'Inside 'theffrontportion 'of hollowshaft '32 andr rigid" therewithfthere is provided a shaft element 44.

The rear'endof hollow s`haft'32 and the edge ofthe tubular hub of l,pinion 42 adjacent to this shaft end" are j. provided with .cooperating dogs or. projections 45, 46,'.

respectively, Ysuch that alostmotionor relative angular displacement of a maximum amplitude equal .to bv tis possibleibetween `pinion42 andshaft 32 ,(which carriesthe rotor wheels:.such..as 32a). v

Ilinionsiw and.. .42..a1-.e .interconnected by...a...pinion 48`in mesh with both of them'.

I il interpose between shaft '.elements.. 43. and. 44, inside shaft'532,La?torsional-1springk-f47. initially;';stressed..so..that .it

directionin which said pinion 42 is itself driven by pinion '48 (this direction is indicated' by arrow f).

The successive cartridges must be separated from the links 49 by means of which they are assembled together to form the belt, and subsequently engaged downwardly into ythever-ticaly introduction passage-33 y.(Figs. 4-to 8.).

The rotor wheel" has five-teeth, i.e. forms lfive circular notches for five successive cartridges of the belt.

The mechanism includes `guidingsurfacesfoar ramps 62-.in theI formof circular arcs vforming the-geometrical envelopes of the cross .sections-of thetcartridgesengaged by the rotor wheel 32a.

The first link 49 is pulled off from 'the cartridge-foibe releasedv.(which cartridge is being held radially by ramps and arranged in suchmanner that, :at the beginning of every feed step of ther mechanism, its nose 51 meets the ffront endofthe link'f`49to be'plled off. v`At'ithis time,

saidlink'is stillengage'd on 'the cartridge'lwhichfafthe en'd ofthisffeed step, is 'to be disengagedzfrom-saidlinkand' engagedin the top'end off introduction passage 33.

This'lever50 is disposed*substantiallyvertically andis .-L-"shap`ed so thatv its horizontal* branch, whichfcarries' nose' 51"at itse'n'd, cot-nes, at the'v beginning fevery'feedstep of ythe. mechanism,as shown `by-Figf4l (lever'50 b'eing'ltlien appliedagainst` abutment -`56fwh`ich limits its movements in the' anti-'clockwise direction) Iintocontac`:twith the` case'o'f ithe' cartridge engaged" in 'linkf'49, nose :51 engaging under' the end r of said link. i y.

TThe uppen'edge :52 (Fig. 8) of"thishorizontalibranh ofletferj'so' is soshaped thatrunde'r the ettecry ofE thermen-.- tiontf thev rotor, 'the cartridge" (held' radiallyvby'l surfaces'- aho'utfits "axis53, against the Vaction vof 1a returnA spring-'54, away"fro`m'the rotor. 'In the course -o'fthis movement; nose 511pullsthe end r offlink 49 away fromv its cartridge, so'thatitinal'lyKFig. 5)*the frontloopoflink 49iis :dis engaged l"from the cartridge laround which it' was lfitted This cartridge is further drivenby'the'rotor'downwardly until', at-the end fthe'feed step (Fig: 6) ,fitis engaged 'be'- tweenthe'uppertedges'of'introduction passage `A33.

The nose "51 of lever 4r50.l extends downwardly towa'r'dl the-left v(as visible in Figs V4, '5,6v and 8) tofform-a'ninclined I-surfa'ce A55 'which,in"the course-'off the vfeed 'stepy oftherotor, gradually 'guidesfthefront end of ylink 49 top of a 'lix'ed evacuation: 'sloping'l surface 56'l along which tlreflink isfto beiA guided.

-fIRetracta'lle ffingers '60 *freely 4Apivo'tableabout shaft-32 and.I subjeetedtothefrenirnfaction of :springs 61 'Iet'the .cartridges fdrop 1 into passage 233' f'and, under the action l`'et' said springs exert a downward thrust on said fcartridgesf- Thefmovements: off'pinonv'z? ftare'itransmittedttofrotor wheelszafasi'fllows:

Since 'ratehetv wlieel. 29 thas'ftve"lteeth, fone pitchrco'rf responds to of `rotatitmrofpinion 27.

fBut-:every' impulse;- movementlofipinion 19 impartsto pinion 27a 'rotation through an angle. greateLthan/7Z?.

At the start (Fig. 11), the-frontfedgesofiprojections 38'rand 45am appledS-byvsprings 41 `and --47' against rear edges of projections 37 and 46.

Every time a shot is tiredpinionfi-startsrotatingn the direetionlindicatedtbythe arrow.

edges of projections the rear edges of projections 38 anni 45 respectively, i. e. when a rigid drive is going to be provided between pinion 27 and rotor wheel 32a.

Both of these last mentioned elements (27 and 32a) rotate together for a short time, then pinion 27 stops when 1t reaches the end of the forward rotation (86) imparted thereto by pinion 19 (which then starts moving in the downward direction, under the effect of spring 17).

Under the effect of springs 41 and 47, pinion 27 and rotor wheel 32a are urged in opposed directions. Wheel 27 can move backward through only a small angle (S6- 72=14) after which it is stopped by the engagement of ratchet wheel 29 with pawl 31. But rotor wheel 32a, after a temporary slowing down and short stopping (which coincides with this backward rotation of pinion 27) moves forwardly under the effect of the expansion of said springs 41-47 until the front edges of projections 38 and 45 are again stopped against the rear edges of projections 37 and 46 respectively.

In the meantime, the parts associated with the rotor Wheel 32a have passed through the respective positions shown by Fig. 5.

At the end of one step, that is to say when springs 41-47 have restored contact between the front edges of projections 38 and 45 and the rear edges of projections 37 and 46 respectively, the parts associated with rotor Wheel 32a are in the position illustrated by Fig. 6.

This gure shows that the rotor wheel is then stopped in a position where it is out of contact with the stationary cartridge designated by reference letter a, itself resting upon the cartridge designated by b. Consequently, these cartridges are not subjected to any thrust from the resilient means (springs 41-47) included in the transmission between pinion 27 and rotor wheel 32a.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efiicient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. A belt feed mechanism for an automatic firearm including a breech case which comprises, in combination, power means for supplying a power impulse in response to every shot fired by this arm, a cartridge belt constituted by a plurality of cartridges and links for interconnecting them, means for guiding said cartridge belt with respect to said rearm, a first element operatively connected with said power means to undergo a movement of given amplitude in a given direction vin response to every power impulse supplied by said power means, a second element operatively connected with said cartridge belt movable step by step so that every step of said second element drives the cartridges of the belt forward toward said firearm, means interconnecting said first and second elements with a play between them smaller than the amplitude of movement of the second element on every step thereof, initially stressed resilient means associated with said interconnecting means for urging said elements away from each other to tend to take up said play between them, means operatively connected with said second element for detaching said cartridges from said belt successively as they are leaving said second element, means interposed between said second element and said firearm for feeding the cartridges detached from said belt to said breech case, said feeding means being arranged temporarily to stop said last mentioned cartridges in given positions, said interconnecting means and said feeding means preventing any contact between said second element and any cartridge stopped in said given positions when said resilient means are taking up said play at the end of every movement of said first element, whereby said play yis integrally taken up after the tiring of every shot.

by a plurality of cartridges and links for interconnecting them, means for guiding said cartridge belt with respect to said firearm, a frame rigid with said guiding means, a rotary member journalled with respect to said frame about an axis vparallel to the direction of tiring of said firearm, means operative by said power means for rotating said rotary member step by step in one direction with a given angular amplitude, a toothed rotor wheel journalled with respect to said frame about an axis parallel to said first mentioned axis, the teeth of said rotor wheel being adapted to engage between cartridges of said belt, a transmission mechanism between said rotary member and said rotor wheel `for imparting to said rotor wheel, in response to the successive rotations of said member a step by step rotation of said rotor wheel of an amplitude equal to one pitch of said belt, said transmission mechanism including at least two elements interconnected with a limited play between them, the total lost motion in said transmission means being smaller than the amplitude of every step of said rotor, initially stressed spring means between said two elements for tending to maintain said play between them, means operatively connected with said rotor wheel for detaching said cartridges from said belt successively as they are leaving said rotor wheel, means interposed between said rotor wheel and said firearm for feeding the cartridges detached from said belt to said breech case, said feeding means being arranged temporarily to stop said detached cartridges in given positions, said play and said feeding means being adjusted to prevent any contact between said rotor wheel and cartridges stopped in said positions when said spring means are taking up said lost motion at the end of every movement of said rotary member, whereby said lost motion is integrally taken up after the firing of every shot.

3. In combination with an automatic firearm system including a fixed support and a firearm proper movable longitudinally with respect to said support under the elect of recoil, with elastic means for returning said firearm proper in the frontward direction after every recoil thereof, said firearm including a breech case, a belt feed mechanism for said firearm which comprises, in combination, a cartridge belt constituted by a plurality of cartridges and links for interconnecting them, means for guiding said cartridge belt with respect to said support, a frame rigid with said guiding means, a rotary member journalled with respect to said frame about an axis parallel to the direction of firing of said firearm, means operative by the recoil displacements of said firearm with respect to its support for rotating said rotary member step by step in one direction with a given angular amplitude, a toothed rotor wheel journalled with respect to said frame about an axis parallel to the first mentioned one, the teeth of said rotor wheel being adapted to engage between cartridges of said belt, transmission means between said rotary member and said rotor for imparting to said rotor, in response to the successive rotations of said member a. step by step rotation of said rotor of an amplitude equal to one pitch of said belt, said transmission means including two pinions operatively connected together, means rigid with said rotary member and one of said pinions respectively interconnected with a given limited angular play, an initially stressed torsion spring interposed between said member and said pinion so as to tend to take up this play. means rigid with said rotor and the other pinion respectively interconnected with a given limited angular play and an initially stressed torsion spring interposed between said rotor and said second mentioned pinion so as to tend to take up said last mentioned play, the sum of the two above mentioned plays being smaller than the rotation ot said rotary member on every step sa'id"plays`and'Sgidiedingmens'being"adjud 'toprev ,l vent any Cn'tct b'eftweenaidrotor'wheelarid,cartridges i l r A* FOREIGN PATENTS stppdinsaid. pinsitions` v'vh'en said` torsion .springs are' 10 558,950 `Great Britain Ian.'28, 1944

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