US2073632A - Cartridge feeding mechanism for automatic guns - Google Patents

Description

March 16,1937. s. G. GREEN I 2,073,632

' CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC GUNS "Filed March 7, 1934 v ZShets-Sheet 1 Inventor Samuel [3 Green Ev @WZ Attorney Mud; 16, 1937." GREEN cARTRIDGE FEEDINGMECHANISM FOR AUTOMATIC GUNS Filed March 7, 1934 Z SheetS-Sheet 2 FILJ Inventor Eamual ELGreE'n EV y Attnrna Patented Mar. 516, 1937 PATENT OFFICE a. "2,613,632 1 s s oanrnmen. FEEDING .MECHANISM FOR v AUTOMATIC GUNS v Samuel G. Green, Gray, Ga.

a pii nonmsrenv, 1934, Serial No. 714,445

s Claims. (01."89-33) Mounted under the at o! Mamba, 1883, as; i amended April 30, 1928; 3700. G. 757) The invention; describedherein may be manuiactured "and used by or for the Government for governmental purposes. without the payment to me of any royalty thereon: j

i This invention relates to a' cartridge feeding mechanism for automatic firearms.

'The purpose'of the invention istoprovide a" cartridge feeding mechanism which will a'ccurate-' lyposition a cartridge with its groove properly presented to'the extractor of the breechbolt, ir-

respective of variations in i the length of the cartridge and irregularity of f loading in the j cartridge belt and without. disturbing the alignment of the bullet and cartridge case or altering the dimension: between the {bullet seat and the base of the cartridge case. a

The invention consists in providing means for engaging acartridge during thermal stage of its movement through the feedway of a gun, displaczoning thecartridge axially to its proper position for in such position against any force tending to move it forwardly extraction andthen holding in the feedway. L s

With oing and otherobjects in view,

;the invention resides in the" novel arrangement and combination of parts and inthe details oi construction hereinafter described and claimed, it

being understood that changes in the precise embodiment of the inventionherein disclosed may aovbe made withinthescope of what is claimed with out departingfrom the spirit of the invention.

A practical embodiment of the invention is illustrated in the accompanying drawings, wherein:

Fig. .1 is a" fragmentary longitudinal sectional view of a machine gun of the Browning type.

vFig. 2 is alplan view of thefeedway oi the gun showing a cartridge before it has been arrested in its passage through the feedway. f .1 l

.Fig. 3 tea siinilarrview showing the cartridge in position for extraction from its belt. Fig.4 is a view in side elevation looking into the feedway. i s

Fig. 5 is an'enlarged plan view partly in section of the 'cartridgestop andguide member. Fig." 6 is a section on the line 5-6 of Fig. 5. Fig.7 is a. modified' forml of cartridge stop and guide member. A

Fig. 8 is a plan view partlyin section showing 50 a modified :method of carryingthe cartridge stop and guide member. i

Figl 9 is a view in elevationtaken generally on the line 8- -9 of Fig. 8.

Fig. 10 is a furthermodification of the guide 55 member applicable to a gun of the Maxim type.

.Fig. 11 is'aview taken on the line HHoi Fig. 10. A v.

Fig. 12 is still another modification of the guide member. I

In the formation of cartridges the bullet is inserted in the mouth of the cartridge case. In the early method of assembly a uniform length of the cartridges wasestablished by gaging between the nose of thebulletand the base of the cartridge case. Since the bullets and cases vary in length this methodof assembly resulted in variable positions of t he seating portion of the bullet so that when a cartridge was inserted in the barrel there was no assurance that the bullet was properly seated. V

In order to remedy this situationthe practice was adopted of assembling the round by seating the ogive of the bullet in an assembly. die and ac-' curately positioning the seating portion of the bullet with respect to the shoulder. and the base of the cartridge. Rounds assembled by this method do not have a, uniform length as the sharpness of the-point effects length.

In movinga cartridgeinto the feedway of a machine gun for the purpose of placing it in a position to be extracted from its belt by the breech 25 7 bolt, it has been the practice to employ a rigid front guide plate which is engaged by the nose. of the bullet. The length of the cartridge there-1 fore determines the position of the groove and rim of the cartridge case and since the length of the cartridge is variable the ultimate position of the groove and rim will also be variable. 7

The extractor on the breech bolt which is to engage them always has a fixed and definite position along the axis of the gun and relative to the feedway when the breech bolt is in battery. In consequence of the variable position of the grooveandrim the. extractor will fail to enter the groove if the cartridge is short and of course the cartridge will not be extracted from its belt on'rearward movement of the breech bolt.

The situation presented when the cartridge is too" long is difi'erent. Since a cartridge-;that- -is too long has its base in the path of movement-of the breech bolt and the extractor on theibolt, the

V cartridge case will be driven forwardly "by'these position of the bulletseat will be changed. When the cartridge'is provided with a supersensitive 'nose fuse this action will. damage the fuse and .may result in a. premature explosion. Furthermore, since the cartridge is not rigidly held in a position parallel to the breech bolt, the alignment of the bullet and cartridge case is destroyed. When a cartridge of this character is inserted into the barrel the bullet will not be properly engaged with its seat, and it will be unsymmetrically presented to the rifling. Gas leakage occurs and is followed by excessive erosion, and loss of accuracy and stability.

Another condition tending to disturb thealignment of the bullet and cartridge case is present when the round being moved into the feedway is not parallel to the axis of the gun. The loading mechanism of the gun possesses suflicient force to move the round into its final position parallel to the axis of the gun and in doing so it causes the bullet to be moved out of alignment with the cartridge case.

The improved device for overcoming all these defects and insuring correct presentation of the cartridge to the extractor and the breech bolt and correct seating of the bullet in the barrel consists of a cartridge stop and guide member A positioned in the side of the feedway B of a machine gun opposite to the side of entry C. The gun illustrated is of the Browning type in which an axially movable breech bolt D carries an extractor E and ejector F, both cooperating to withdraw a round of ammunition G from its belt H.

The cartridge guide member A (Figs. 2 and 3) is preferably formed from a single piece of metal so that its bearing and contact surfaces may be accurately positioned by a single measurement from established surfaces wherever selected.

The member A includes an arm 5 engaging the outer face of the receiver plate 6 ofthe gun and secured th'eretoby rivets 1. The shoulder 8 at the forward end of the arm bears against the edge of the receiver plate at the rear'of the feedway and provides one of the established surfaces from which measurements are madei The under side'of the member A is provided with a longitudinally extending groove 9 fitting on the edgeof the receiver plate 6. The floor of the groove is in the plane of the main under surface III which rests on the trunnion block ll of the gun. The surface I is used as a basis for vertical measurements.

The member A is formed with two curved cartridge engaging stop surfaces l2 and I3 which arrest movement of the cartridge through the feedway of the gun and position it in alignment with the breech bolt which is to extract it from its belt. The front surface I2 is semi-circular and merges with the inner surfaces of spaced tangential fingers l4l4. As clearly shown in Fig. 4, the front portion of the member A in which the surface I2 is formed has its under edge fitting in a groove l that extends transversely acrossthe trunnion block I l A slot 16 in the member Ain rear of the surface l2 accommodates the finger I! of the feed pawl l8 of the gun.

The stop surface I3 is an appreciable distance in rear of the stop surface l2 and is less than a semi-circle.

A pawl [9 having its front portion disposed in a slot 20 in the member A is mounted on a pivot pin 2|. The tail 22 of the pawl is adapted to engage the fioor of the slot and limit rotational movement of the pawl under the influence of a spring 23 which acts on the rear end of the pawl. A lip 24 on the rear end of the pawl I9 is adapted to engage in the groove of the cartridge.

As shown in Figs. 1, 2 and 3, a guide plate 25 defining the forward wall of the feedway is mounted in the raised front portion of the trunnion block H and yieldingly held by a spring 26.

A fixed pin 21 extending through a slot 28 in the plate 25 limits movement of the plate.

When the machine gun is in operation the breech bolt moves rearwardly on recoil and the extractor carried by the bolt withdraws a round from the feedway and holds the rim of the round in the T-slot in the front face of the bolt. During the continued rearward movement, the extractor is cammed downwardly to position the round in line with the bore of the barrel so that on forward movement of the bolt the cartridge is inserted into the chamber of the barrel. While this action is occurring, the feed pawl has engaged another cartridge and moved it across the feedway until arrested by the cartridge guide member A. As the bolt arrives in battery the extractor strikes the base of the positioned cartridge in the feedway and rides over it, and if the cartridge should still have its base in the path of movement of the bolt it will be struck by the bolt and moved forwardly. The stop surface l3 holds the cartridge against vertical displacement when the latter is struck by the extractor.

The cartridge stop and guide member A function in the following manner. As the cartridge enters the feedway, either by pulling on the belt or under the influence of thefeed pawl I, it approximately occupies its correct position longitudinally of the gun. If it is forward of its ultimate correct position due to improper loading in its belt, the nose of the bullet may engage the cam surface 29 on the front guide plate 25 and the cartridge and its belt will be moved rearwardly until the belt or the link of the belt engages the front face of the member A. The spring 26 of the front guide plate does not have sufficient force to displace the cartridge relative to its belt; If the base of the cartridge is still forward of its correct position the lip 24 of the pawl l9 will engage the rim of the cartridge and upon rotation of the pawl due to travel of the cartridge, the lip and consequently the cartridge will be moved rearwardly. When the cartridge has been arrested by the stop surfaces 12 and I3 its base will be in the correct position to fit in the T-slot of the bolt and its groove will be engaged by the extractor.

If a situation should arise where the base of the cartridge is so far to the rear that the lip of the pawl does not reach the groove, then the 4 cartridge is moved forwardly by the extractor on the breech bolt or by the breech bolt until the lip 24 snaps into the groove and securely holds the cartridge against further forward movement. v

Irrespective of the variation in length of the cartridge or irregularity of loading in its belt, it is presented tothe breech bolt and extractor without having the alignment of bullet and cartridge case disturbed and without altering the dimension between the seat of the bullet and the base of the round. The withdrawal of the cartridge from its belt in the feedway takes. place in the usual manner, the link or belt being stripped by In Figs. 8 and 9 the pawl 36 is carried by a block 31 which fits between the stop members 38 and 39. The pawl is partially disposed in a recess 40 in the center of the block and is mounted on a pin 4|. The block is-held in place by means of opposite studs 42--42 which enter apertures 43-43 in the stop, members and also by means of studs 44 which enters apertures 45 in the stop member 39. The stop members 38 and 39 are present on existing guns and are selectively mounted on either side of the feedway depending upon whether the feed isto be from right to left or from left to .right. The block being symmetrical may be reversed and mounted on either side of the feedway.

In guns of the Maxim type (Figs. 10 and 11) the extractor moves vertically upward as the breech bolt arrives in battery. In this situation the upper side of the cartridge is preferably engaged by a resilient guide member 46 which is fixed as to movement transversely of the gun by means of a bracket "secured to the top of the casing 48 as by rivets 49. The member 46 has two forwardly inclined arms 50-50 adapted to engage the groove of a cartridge being fed from left to right or from right to left and cam the cartridge to its position for extraction from the belt. The ends of the arms 50 are disposed in recesses in the side plates 52 of the casing. V

In Fig. 12 the front guide plate 53 serves to displace the cartridge and a plunger 54 serves to engage in the groove of the cartridge to hold it in proper position for extraction. I claim: r

1. In an automatic firearm, a receiver casing, having a transverse cartridge feed channel, a yieldingly mounted plate in the front wall of the channel, a cartridge stop member disposed in the channel, a pair of spacedstop surfaces on said member, a pawl pivotally mounted in said memher and having a lip on its rear end for engaging the groove ofa cartridge case, a spring normally holding the pawl at an angle to the longitudinal axis of the firearm with its 'lip beyond the stop surfaces and in the path of movement of a cartridge moving across the feed channel. M

2. In an automatic firearm, a receiver casing having a transverse cartridge feed channel, a I cartridge stop member disposed in the channel,

a pair of spaced stop surfaces on said member, a

pawl pivotally mounted in said member and hav-\ 3. In an automaticfirearm, a receiver casing having a transverse cartridge feed channel, a cartridge stop member disposed in the channel, stop surfaces on said member, a pawl pivotally mounted in said memberand having a lip onits rear end for engaging the groove of a cartridge case,a spring normally holding the pawl at an angle to the longitudinal axis of the firearm with its lip beyond the stop surfaces and in the path of movement of a cartridge moving across the feed channel.

4. In an automatic firearm, a receiver casing having a transverse cartridge feed channel, a yielding'ly mounted cartridge guide plate in the front end of the channel, means for limiting ,movement of a cartridge across the channel, a

pawl mounted for movement in the plane of the feed channel, and a lip on the pawl for engaging a cartridge moving across the feed channel and seating in the groove of the cartridge.

5. In an automatic firearm, a receiver casing having a transverse cartridge feed channel, means for limiting movement of a cartridge across the channel, a pawl mounted for movement laterally of the feed channel and in the plane of the car-. tridge moving across the channel, and a lip on the pawl for engaging a cartridge moving across normally at an angle to the longitudinal axis of the firearm, and means on the lever for engag-j ing the rim of the cartridge and axially displacing the cartridge upon rotation of the lever to a position parallelto the axis of the firearm.

'7. In an automatic firearm, a receiver casing having a. transverse cartridge feed channel, means for limiting movement of a cartridge across the channel, a lever normally at an angle to the longitudinal axis of the firearm, and means on the lever for engaging the rim ofthe cartridge and axially displacing the cartridge upon rotation of the lever toaposition parallel to the axis of the firearm.

8. In an automatic firearm, a receiver casing lgavirig a transverse cartridge feed channel, means or limiting movement of a cartridge across the ing a lip on its rear end for engaging the gro channel, and a resiliently mounted rigid member \g isposed in the path of movement of a cartridge oving across the channel and arranged to engage the rimof the cartridge to hold the cardisplacement.

SAMUEL G. GREEN.

of a cartridge case, a spring normally holding the pawl at an angle'to the longitudinal axis of the firearm with its lip beyond the stop surfaces and in the path of movement of a cartridge moving across the feed channel.

tridge against forward

Images