US2417080A - Cartridge feed system - Google Patents

Description

J. L.. LociHHr-:AD

CARTRIDGE FEED SYSTEM 3 Shee-ts-Sheet l Filed Aug. 24, 1940 INVENTR .10h11. L- LCI chhand.

BY L l l f1 11, 1947 J. L.. LOGHI-:EAD 2,417,030

CARTRIDGE FEED SYSTEM Filed Aug. 24, 1940 '3 Sheets-Sheet 2 INVENTOR TG1-Un. L.- Lcsc'hheu A'ITORNEY .1.' L.. Loan-:HEAD 2,417,080

CARTRIDGE FEED SYSTEM Filed Aug. 24, 1940 3 Sheets-Sheet 3 INVENTOR Jahn. l.- Lmchhanl BY e "l" ATTORNEY sPatented Mar. 11, 1947 g 2,417,080 CARTRIDGE FEED. SYSTEM' John L. Lochhead, Springfield, Mass.;v assigner to United States of Americarasrepresented by the Secretary of War Application August 24, 1940, Serial No. 354,070

(Cl. 'S9- 33) (Granted under the act of March 3, 1883, as

4 Claims.

amended April 30, 1928; 370 0. 757) Theinvention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

v This invention relates to an improved cartridge feed system particularly adapted for use in ma` chine guns of the Browningtype.

-In'the present Browning type of machine gun the cartridge belt is advanced step-by-step through the feedway by a reciprocating slide and feed pawl which are actuated by a lever oscillated by the movement of a breech bolt in recoilA and counterrecoil. The lever is at present oscillated in such manner that the cartridge belt advancing stroke of the slide and feed pawl is performed on the counterrecoil movement of the bolt which is objectionable in that the driving spring used to move the bolt in counterrecoil must also provide the energy for advancing the cartridge belt. The two-fold function imposed upon the driving spring by the present cartridge belt advancing system under certain conditions becomes a burden, with the result that the cyclic rate of the gun is reduced because of the weakness of the driving spring action due to the burden of both driving .the bolt in counterrecoil and providing the energy to advance the cartridge belt. Under some conditions the driving spring action is so weakened as to be of insufficient strength to properly close the bolt.

It is an object of the present invention to obviate the inherent weakness of the cartridge feeding system presently employed as standard on the Browning type machine gun. A

It is a further object of the invention to relieve the driving spring used in the Browning type machine gun to drive the breech bolt in counterrecoil of the additional function of providing the energy to advance the cartridge belt.

It is still a further object of the invention to use the recoil movement of the breech bolt of a machine gun, such `as the Browning type, for v f example, to perform the cartridge belt'advancing `step inthe cartridge feeding operation of the gun.

\ Another object of the invention is to utilize the n forceof recoil during firing to provide the source of energy `for advancing the cartridge belt.

Another object ofthe invention is to increase the cyclic rate of a machine gun.

Still another object of the invention is to `make inA . 2 possible the satisfactory feeding of cartridge belts of greater length than hitherto feasible.4

Another object of the invention is to provide for the advance of the cartridge feed belt through the feedway from either the right or left hand side of the `gun by the recoil movement of the breech bolt.

Still another object of .the invention is to arrange the beltvfeed mechanism in such a. manner that the belt feed pawl and the belt feed pawl reciprocating devices may relatively reciprocate with respect to each other in the event of excessive pressure being exerted on the beit feed pawl due to feeding malfunctions caused by failure to properly feed the belt or extract cartridges therefrom through premature ignition of a cartridge or cartridge of the sic-called short round type, and similar reasons equally familiar to those acquainted with the art.

The specic nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a fragmentary plan View partially in section of a machine gun of the Browning type showing the cartridge belt feeding mechanism of -this invention in relation to the breech bolt in battery position;

Fig. 2 is a fragmentary elevational view partially in section of the right hand side of a machine gun of the Browning type showing the cartridge belt feeding mechanism of this invention in relation to the breech bolt in battery position;

Fig. 3 is an enlarged transverse sectional view taken on the 1ine3-3 of Fig. 2;

Fig. 4 is a View in elevation partially in section of the belt feed lever of this invention;

Fig. 5 is abottom plan View of the belt feed lever of this invention showing in-dashed lines how the lever may be arranged for use in feeding a cartridge belt reversely of the direction in which the lever as arranged in full lines is adapted to feed the cartridge belt;

Fig. 6 is a side elevation of the belt-feed slide of this invention;

Fig. 7 is aside elevation partially brokenaway 'and in section showing the belt feed slide body of this invention;

Figs. 8 and 9 are bottom plan views of the structures shown in Figs. 6 and '7, respectively;

Fig. l is a plan view of a flat spring uned in the belt feed slide and bodyassembly;

Figs. 11 and 12 are plan and elevation views, respectively, of the belt feed pawl;

Fig. 13 isaV view in perspective of a reversible cut. off block used in the breech bolt assembly.

Referring row to the drawings by characters of reference and more particularly to Figs. 1, 2 and `3 there is shown the cartridge belt feed mechanism of this invention as applied to a machine gun of the Browning type, although it `will be understoodthattheprinciples of the invention are applicable with equal facility to any desirable machine gun or similar automatic weapon.;

As in. the case of all machine guns of the Browning type a breech bolt I0 is mounted in a receiver II for reciprocable movement in recoil and counterrecoil from and to a normal battery position, respectively, which latter position is shown in Figs. 1 and 2. In the cartridge belt feed vmechanism ofthe present invention; as hitherto, reciprocable movement of the bolt I0 is utilized to advance-the belt I2 through feedway I3 step- `by-step. In the' organization of the feed mechanism of the'present invention, however, recoil movement of bolt. IOAis-utllizedto advance the belt I2 instead of rcnunterrecoilmovement of the bolt as heretofore. I

f To ,this end thecartridge belt feed mechanism comprises generallyua belt feedpawl assembly I4 A:mounted ina-suitable guideway I5 located in the vpi/votedoover. I6 over the feedway I3 for reciplrocating movement transversely of the direction of reciprocation of -bolt I0 and a lever II mounted 'on the cover-I6 intermediate its 'ends by means of astudVas indieatedgat I8adapted to be oscillated by reciprocable movement of the bolt and in turn through suchgoscillation reciprocate the belt feed .pawl assembly I4 in a manner to advance the 3, 'I and 9,-is of general channel shape in crossseotion and( islongitudinally grooved adjacent its flower outsidecorners, as indicated at 20, or otherwisesuitablyl-formed to cooperate with complementary-guideelements 2| formed in the guide- -way I uncover-.16 for the purpose of.retaining the body, member 4mounted within guideway I5 ioiwreciprocable movement vas shown in Fig. 2. i `The interiorfacessoftheflaiigesn of body member iIS fare..longitudinally.` grooved or similarly .formedias indicated at 23 to provide a guideway to receive lthebelt feed pawl slide for relative reclprocable movement as more particularly heremarrer described, and the outside faeesof flanges 22 are provided with opposed vertically extending belt yfeed lever recesses'I 24. vAlso-the Web 25 of body member I9 .is cut away, as at 26, between the anges 22- adjacent one end portion thereof andthe opposite end portion is beveled as indin The belt feed pawl assembly I4 also comprises I a' belt feedpawlslideZB coextensive in length with the body member I9; andadapted to slidably in Fig. 3.

nt within and `loeretained 1n `the guideway of the bodymemberhthrugh interengaglpg relation of the complementary grooves 23`of the body member and projections 29 on the slide 38 .Bis clearly shown in Fig. 2. The upper surface of slide 28 is formed with an'upstanding projection 30 which extends above the upper surfacessof the flanges 22 of body member I9 in such manner as to be en'- gageable with a projection 3| depending centrally of a longitudinal groove in the transverse surface vdefining guideway I5 in the cover to limit outward sliding movement of the slide as shown Upon its'end portion remote /from projection 38 4the slide 28 is provided with transversely spaced depending axially aligned perforated ears 32. The slide 28 is perforated on and normally of its longitudinal axial line, preferably on the side of its transverse median line adjacent its end portion bearing the ears 32, as indicated at 33 and the bottom surface of the slide is formed with a transverse recess 34 disposed symmetrically with respect to the perforation as shown in Fig. 6. The bottom surface of the slide is also formed to provide a longitudinal'recess 35 extending upwardly and. outwardly to its rightmost end from the horizontal defining surface of recess 34 and a similar recess 36 extending upwardly and outwardly Yto its leftmost end from a point intermediate the recess 34 and ears 32 also as shown in Fig; 6. The surface del ning the transverse wall of recess 36 is longitudinally grooved as indicated at 31 from a point inwardly from its leftmost end to and with its transverse wall coinciding 'with the transverse wall of recess 34.

A flat spring 33 shown in Fig. 10 of the same general configuration as and adapted to be fitted within the recessed portion of slide 28 defined by the recesses 35, 34 and groove 31 is formed with an end vportion 39 disposed at the same angle with regard to its body portion as the angle of the beveled portion 2l of the body member I9.

.The spring 38 is secured to the slide 28 within the A belt feed pawl 4I shown in Figs. 3, l1 and 12 is pivotally mounted on the ears 32 of slide 28v by means of a pin 42 andis formed with a'seat 43 adapted to engage the upper surface of recess 36 of the slide to limit outward turning movement of the pawl and a seat 44 engageable by the adjacent end portion of the spring 38 in such manner as to be normally biased to a position with the seat 43 engaging the upper-surface of. recess 35.

The belt feed lever Il shown in detail in Figs. 4 and 5 is comprised of two arms 45 and 46. The arm 45 at one end is formed with a projecting hub 41 and at its opposed end A48 is suitably formed to be engageable within a recess 24 ofvthebody member I9. Arm 45 is also formed. wi th .,t'wo grooves 49 extending radially frornfhub 41Hln proper arcuately spacedrelation-,as rnore `ully explained hereinafter.r Arm,y 46 in .the'FfoiI'rn of the invention herein shown is `shorter than yarm 45 for a purpose subsequently made apparent and is perforated at 58 adjacent one end to receiveftlie hub 4l of arm 45. The end of arm 46 adjacent perforation 5U is formed witha'l projectlonl adapted to be positioned in either one of the grooves 49 of arm 45 whilevth'e opposecle'nclof arm 45 is provided with Ias'tud 52 projecting lin opposed relation. to projection 5I. B'yth'e provi- ,sion pf the hub 47 the bearing of arm 45/ on stud` Ill is increased and 'likewise thebering of 45 and 46 assembled with the perforation 50 of arm 46 receiving" the hub41 of arm 46 and the projection I of arm 46 positioned within either one of the grooves 49 of arm 45 are mounted on the stud I8 and secured thereon by any suitable means such as the washer 53 and pin 54. The Ilever I1 is mounted on the stud IB with the stud 52 of varm 46 in depending relation and means, such as the spring actuated plungers 55 carried by the lever I1 on either side of the stud I8 coact with the cover 'I6 to maintain the lever in a normal position relative to the cover, when the latter is raisedl.

The upper surface of the breech bolt I0 is provided with cam grooves 56 and 51 operable to oscillate the lever I1 for right and leftfhand feed of the cartridge belt through the feedway I3, respectively. Each cam groove is extended in parallelism, with the sides of the bolt from the rear end of thelatter forwardly and near its forward end portion is inwardly directed in such manner as to impart pivotal movement under uniform acceleration to lever I1 when moved relative to the lever stud 52 normally disposed therein, To facilitate the use of either cam groove, both grooves 56 and 51 are designed to extend to close proximity of the' forward end of the bolt where they terminate in overlapping relation symmetrically of the longitudinalmedian line of the/bolt. .That portion of the bolt IIJ upon which the cam grooves56 and 51 overlap is vertically recessed as indicated at 58 andV a cut-off block 59 shown in detail in Fig. 13 is snugly receivable within the recess 58 and formed With one end surface at 56' to constitute'a continuation of cam groove 56 -when disposed in the recess 58 with such surface uppermost and similarly formed on its opposed end surface 51 to constitute a continuation of cam groove 51 when the latter end surface is uppermost. The cut-off block is transversely pierced as shown at 68 in Fig, 13 and is retained in position in the recess 58 by a headed pin 6I which is inserted in a perforated part 60 of the cut-off block as shown in Fig. 1.

To retain the headed pin 6I in position in the bolt I0 the forward end portion of the driving spring rod/62 is extended to pass through a transverse opening 63 in'the head of pin 6I as will be clearly seen in Fig. 1.

To assemble the feed mechanism the spring 38 is secured to the belt feed pawl slide 28 and the belt feed pawl is pivotally connected to the ears 32 as shown in Fig. 3. The slide 28 is then assembled with the body member'IS by inserting the rightmost ends of guide projections 29 thereon in the leftmost ends of complementary grooves 23 of Vthe body member as viewed in Fig. 3. The

end 39 of spring 38 is then flexed into recessv 35 and the body member and slide moved to 6 dependent upon the angle of bevel 21 and the tail 39 of spring 38.

At other times, in `normal operation of the action, there will be a shock-absorbing function performed by the spring. which will lessen liability of strain of belt links and cartridge cases.

Upon completion of assembly of the slide 28 and body I9, the unit comprised of these elements is mounted in the guideway I5 formed in the cover I6 of the gun, and the manner in whichzit is mounted in guideway I5 will be dependent upon whether it is desired to arrange the gun for right or left, hand feed 0f the cartrldge belt through feedway I3. If the gun is to be arranged for left hand feed then the unit will be mounted in guideway I5l as shown in Fig. .3 and vice-versa for right hand feed.

For the purpose of this description it willbe assumed that the gun is to be arranged for left hand feed. therefore, the unit comprised of the slide 28 and body member will be inserted within guideway I5 from the right side of the latter with the complementary guide elements 20 and 2I in interguiding relation and the projection 30 adapted to abut the right side of abutment or projection 3I as shown in Fig. 3;

The belt feed lever I1 is next assembled for actuating the body member I9 for left hand feed by arranging the projection 5l on arm 46 to be received within the rightmost groove 49 of arm as viewed in Fig. 5, and with the perfog ration of arm 46 receivingr tlie hub 41 of arm 45. As thus assembled the lever I1 is mounted with its hub 41 on stud I8, with the Stud 52 of arm 46 projecting away from the cover I6, and the forward end portion 48 of thearm 45 disposed in the adjacent recess 24 of the body member I9 and secured onto the stud I8 by the retaining collar 53 and pin 54.

Since in the illustration shown, it was assumed that the gun was to be arranged for left hand feed, it will be necessary to utilize the cam groove 56 in bolt I6 to oscillate lever I1 through stud the relative positions shown in Fig. 3 whereupon l the` end 39 of spring 38 is released to 4engage the cooperating bevel surface 21 on'body member This completes assemblyof the body and slideandthe spring 38 will serve to retain these two elements in the relative positions disclosed in Fig. 3 under ordinary operating conditions. If, however, the belt feed pawl encounters an excessive load due to a jam the body member I8 may move relative to the slide, as such excessive load Will cause the angled end 38 of spring 38 to cam out of securing engagement with the body member I9 through the bevel surface 21, it being understood of course that the load required to part the body member I9 and slide 28 is 52, therefore, cut-olf block 5-9 will be arranged in recess 58 with its cam surface 56' uppermost and forming a. continuation of cam groove 56. The cut-off block is secured in position within the recess 58 by inserting the pin 6I through the perforation 60 thereof and the pin 6I is in turn secured within the bolt by inserting the projection 63 of the driving spring rod 62 through the head of the pin all as shown in detail in Fig. 1.

The feed mechanism of this invention is now assembled on the gun for left hand feed and will function during operation in the following manner: Plungers 55 on lever I1 and engaging cover I6 will so relatively positionthe lever with respect to the cover that'when the bolt I0 occupies 'a predetermined position the stud 52 will fall within a cam groove 56x01- 51, asthe case may be. when the cover is lowered to closing position and latched to the receiver as is well understood in the art. With the cover lowered to closing position and latched to receiver Il, with stud 52 positioned in cam groove 56, the bolt I0 in battery, and endmost cartridge 64 in the axial plane of the bore of the barrel abutting the cartridge vfeed stops in the feedway I3, the belt feed pawl 4I will engage the next adjacent cartridge 65 and the belt holding pawl 61, arranged on the left side of the gun in the case illustrated, will also engage cartridge 65h to hold the loaded belt in place. To load the gun the bolt I0 is drawn to its counterbattery position. During initial movement of the bolt I0 in a recoildirection the lever I1 will not -be moved from the position shown in Fig. 1 owingr to the delay or dwell period in cam groove 56; that is, owing to the fact that during this initial movement the cam groove 56 will relatively move in counterbattery tangent to the initial position of stud 52. Upon initiation of movement of bolt I toward its counterbattery position the usual extractor thereon, not shown for the sake of clarity, will extract cartridge 64v from the cartridge feed belt and under the influence of the extractor caml in the cover, also 4 omitted, move cartridge 64 downwardly into the T-cut in the forward face of the bolt. The cam groove 56 is so designed and correlated to the length of arm 46 of lever I'I that when the bolt has been `moved in recoil to cause cartridge 64 to clear feedway I3 the curved portion of the cam groove will engage stud 52 and swing lever I1 about its stud I8 moving arm 45 to the right, or

downwardly as viewed in Fig. 1 under uniform acceleration thereby moving the belt feed pawl 4I to the right to advance the pawl 4I to the right and advance the cartridge belt one step. Completion of the movementof bolt I0 in a. re-

coil direction will cause cartridge 65 to occupy the positionformerly occupied by cartridge 64 in the feedway I3 with belt holding pawl 61 engaging the next succeeding cartridge 66. Release of the bolt from its counterbattery position for movement in counterrecoi1 under the driving energy of the driving spring and rod 62 will effect chambering of cartridge 64 and reposition pawl 4I in its initial position of Fig. 3. The gun is now conditioned for firing and will upon firing cartridge 64 repeat the cartridge feeding cycle above described in connection with loading.

If, for any reason, the rightmost cartridge 64 in feedway I3 fails to be extracted or a jam of some other source occurs the slide 28 and pawl 4I attached thereto will under the excess force part from body member I9 by overcoming the spring 38 which urges its tail portion 39 into engagement with the bevel surface 21 on body member I9.

Due to the long delay or dwell period in the cam grooves 56, 51, it will be apparent that ii for any reason the rightmost cartridge 64 in feedway I3 is withdrawn by the extractor on the bolt I0 and the bolt fails to travel its normal cyclic distance in recoil then the long delay in the cam grooves will serve to prevent advance of the succeeding cartridge 65 in the feedway, thereby obviating the condition that the cartridge 64 carried by the bolt could strike the primer of the succeeding cartridge 65 in the feedway.

By the arrangement herein shown the throw of each cam groove has been reduced to substantially 20 degrees, thereby increasing the leverage on lever Il. Due to the decreased throw of the cam grooves the lever arm 45 has been shortened and the stud I8 repositioned with respect to guns arranged to feed on the counterrecoil stroke of the bolt thereby facilitating proper reciprocation of the belt feed pawl which in the instant case advances the belt through moving the cartridge 65 next succeeding the endmost cartridge 64 in the feedway.

While the device has been described in connection with the gun arranged for left hand feed it will at once be obvious that it may also be ar ranged for right hand leed by rearranging the lever I1 as shown in dashed lines in Fig. 5; reversing the unit in guideway I comprised of the slide 28, body member I9 and feed pawl III; reversing the cut-off block 58; and changing the belt holding pawl 61 to its corresponding position on the right side of the gun; and using cam groove 5l to drive lever Il through stud 52.

Having now described a present preferred embodiment of the invention I claim:

1. In an automatic gun oi the type having a reciprocable breech bolt movable to a counterbattery position by the force of recoil, a cartridge feeding mechanism comprising in combination a body member reciprocable transversely of the direction of movementrof said bolt, a slide mounted on said body member adapted for relative movement inl the direction -oi? reciprocation thereof. a. flat resilient member secured to said slide, means detachably interconnecting the flat member and body member whereby movement of the latter will be transmitted to the slide, a pawl pivotally mounted on theslide, a. lever pivoted on the gun and having one end portion engageable with the body member to reciprocate the same upon oscillation of the lever and means dening a cam track on said bolt adapted to oscillate the lever upon reciprocation of the bolt, said cam track and lever being correlated to move the body member in cartridge advancing direction during movement of the bolt toward counterbattery position.

2. In a feed mechanism for an automatic gun, l

a body member of general channel shape in cross section formed with opposed vertical recesses extending inwardlyfrom the outside of the opposed anges, the web of said body member being cut-away between opposed anges for a portion of its length at one end and beveled at its opposed end, the interior of the flanges of said body member being formed to provide longitudinal guide elements, a slide element having longitudinal guide elements complementary to the first named guide elements slidably mounted between the flanges of said body element with the guides in complementary relation, vsaid slide having a pair of transversely aligned ears depending over the cut-away web portion of the body and being recessed upwardly, a pawl mounted on the ears and depending through the cut-away portion of the body, a iiat spring secured to the slide intermediate the confronting faces of the slide and body and engaging the pawl in outwardly biasing relation, said spring also being formed with an angled tail portion engaging said beveled end in complementary relation to secure the slide to the body.

3. The structure of claim 2 wherein the flat spring is secured to the slide intermediate its ends with one end portion engaging the pawl and said slide is upwardly and outwardly recessed from the zone of attachment of the spring thereto to provide for upward fiexure of the spring whereby the pawl may have limited pivoted movement and the angled end of the spring disengaged from the beveled surface on the body to permit separation of the body and slide.

4. In a machine gun having a bolt and drive spring for its counterrecoil wherein belted cartridges are fed transversely to a position over the chamber of the gun and a bolt-actuated extractor withdraws a cartridge from its belt to a loading position alined with the barrel for chambering by the bolt on counterrecoil, the feeding means including a transversely reciprocable pawl device. a lever pivoted on the gun for oscillation parallel to the plane of feed, its forward arm connected to the pawl device, and its rearward arm having a wiper engaged. with a cam groove in the bolt, said cam extending longitudinally of the bolt and REFERENCES CITED The following references are of record in the 15 file of this patent:

Number Number UNITED STATES PATENTS Name Date Frommer Sept. 17, 1912 Smith Jan. 14, 1919 Moore Nov. 21, 1933 Homberg July 14, 1936 Gorton Apr. 26, 1937 Petry Feb. 5, 1918 Avigdor July 25, 1939 Sutter Oct. 3, 1922 FOREIGN PATENTS Country Date British Nov. 22, 1928 Norwegian Oct. 24, 1927

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