US2104033A - Bolt operating mechanism for machine guns - Google Patents

Description

Jan. 4, 1938. s GREEN 2,104,033

BOLT OPERATING MECHANISM FOR MACHINE GUNS Filed Oct. 11, 1935 24 A; /4 Inventur Emmuel, [3. Green J MMW PatentedJan. 4, 1938 PATENT orrica BOLT OPERATING MECHANISM FOR MACHINE G UNS Samuel G. Green, Gray, Ga.

Application October 11, 1935, Serial No. 44,572

4 Claims.

(Granted underv the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757') 5 This invention relates to a bolt operating mechanism for machine guns.

. Machine guns are provided with a breech bolt handle to permit manual retraction of the bolt in order to reproduce the action of the gun l mechanism during flringfor the purpose of initially loading the gun and correcting stoppages. The reciprocation of the bolt handle during firing of the gun has frequently caused injury to members of the gun crew. 'In the heavy 15 machine gun such as the .50 caliber, a considerable eflort is required to initiate retraction of thebolt and in performing this operation the gunners hand is frequently injured.

The purpose of this invention is to facilitate 0 manual retraction of the breech bolt and to this end the bolt handle is arranged to have an initial lever action. The handle is also arranged so that it is not retracted by the breech bolt during firing of the gun.

With the foregoing and other object in view, the invention resides in the novel arrangement and combination of parts and in the details of construction hereinafter described and claimed, it being understood that changes in. the precise 30 embodiment of the invention herein disclosed may be made within the scope of what is claimed without departing from the spirit of the invention.

A practical embodiment of the invention is 35 illustrated in the accompanying drawing, where- Fig.1 is a plan view of a machine gun equipped with the improved bolt operating mechanism.

Fig. 2 is a view in side elevation.

Fig. 3 is a'sectional view on the line 33 of Fig. 2.

Fig. 4 is a plan view of the slide.

Fig. 5 is a view in side elevation thereof.

Referring to the drawing by characters of 45 reference, there is shown the breech casing 5 of a machine gun having a side plate 6 with a longitudinally extending slot 1 in which the stud 8 of a breech bolt 9 reciprocates during actuation of the gun. A frame l0 having a slot I I correspond- 50 mg to, but wider than the slot 1, and in alignment therewith, is attached to the outside of the side plate by a plurality of screws or bolts l2.

:The slot H in the frame extends forwardly beyond the front end of the slot I to accommo- 55 date a slide is which is disposed in front of the stud 8 of the breech bolt when the breech bolt is in its extreme forward or "in battery position. The slide is provided on its upper and lower sides with tongues I l-l4 which ride in grooves l5-I5 formed between the rail portions of the frame and the side plate 6. The rear face of the slide is formed with a semi-circular recess It for engaging the stud 8 of the breech bolt.

A lever I! having a heel l8 and a toe I9, is pivotally mounted between the heel and toe on a stud bolt 20 which is threaded in the slide. The lever is laterally confined between a collar 2| and a nut 22 on the bolt 20 and a torsion spring 23 embracing the collar has oneendattached to the collar and the other end to the lever. stop pin 24 is carried by the slide forwardly of the bolt 20 in position to engage the under side of the heel I8 01 the lever when the lever is in an upright vertical position where it has been moved and is held by the spring 23.

A stud bolt 25 is threaded in the frame I 0 and is positioned directly underneath the bolt 20 when the slide carrying the bolt 20 is in the forward position. The bolt 25 preferably carries a roller 26 which is adapted to engage the under side of the toe IS.

The upper end of the lever carries a laterally projecting handle 21 which is adapted to be grasped by the gunner and acted on to retract the slide.

A plunger 28 is carried by the frame and is normally urged by ajspring 29 into the path of movement of the slide. When the slide is in its foremost position the beveled or pointed end 30 of the plunger engages in a recess 3| in the slide.

In the normal position of the parts the breech bolt 9 is in battery and the slide I3 is atthe forward end of the frame where it is releasably held against retraction by the plunger 28 and positively held against forward displacement by virtue of the engagement of the toe IQ of the lever with the roller 26, the lever being limited to an upright vertical position because of the engagement of its heel l8 with the stop pin 24. The slide and lever remain in this position when the breech bolt reciprocates in automatic operation of the gun.

When it is desired to manually retract the breech bolt, the handle 21 is grasped by the gunner and a rearward pull is exerted. This action produces rotation of the lever I1 about its pivot 20 and since the toe of the lever is fulcrumed on the roller 26, the pivot, and the slide l3 to which is it secured, are displaced rearwardly. The slide being connected to the breech bolt smoothly initiate retraction of the breech belt which at this time is being unlocked with respect to the barrel. v

When the lever and slide are retracted a distance sufficient for the toe l9 to clear the roller, the eflort exerted on the handle causes the lever to be rotated about its pivot until the toe engages the stop pin 24 of the slide I3. The lever is now in position parallel to and in line with the slide I3 so that the pull on the lever is directly transmitted to the slide.

When the slide is fully retracted as shown in dotted lines in Fig. 2 the lever is released. The breech bolt is now free to be returned into battery by its return spring which was energized upon retraction of the breech bolt. The stud 8 of thebreech bolt being in rear of the slide causes the slide to be driven forwardly. As soon as the lever is released, the torsion spring 23 restores it to the upright position where the heel l8 engages the stop pin 24. The slide is arrested in its forward movement when the toe I9 of the lever engages the roller 26.

I claim:

1. In a machine gun, a casing having a side plate provided with a slot; a breech bolt reciprocally mounted in the casing and having a stud extending through the slot, 8. frame on the outer side of the side plate, a slide reciprocallymounted in the frame and engaging the forward face of the stud on the bolt, a lever having a toe and a heel and pivotally mounted on the slide between the toe and heel, a stop pin carried by the slide in front of the pivot of the lever, a spring normally acting to rotate the lever to a vertical position with itsheel engaging the stop pin, and a member serving both as a fulcrum and a stop carried by the frame below the pivot of the lever and engageable by the toe of the lever.

2. In a machine gun, a support, a breech bolt reciprocally mounted in the support and having a projecting member, a slide reciprocally mounted on the support and engageable with .the' front face of the projecting member of the breech bolt, a lever having a toe and a heel and pivotally mounted on the slide between the toe and heel, a stop pin carried by the slide in front of front face of the projecting member of the breech bolt, a lever having a toe and a heel and pivotally mounted on the slide in front of the bolt element and between the toe and heeL-a stop pin carried by the slide in front of the pivot of the lever, and a member servingas a fulcrum and a stop carried bythe support below the pivot of the lever. v

4. In a machine gun, a support, a breech boltreciprocally mounted in the support and having a projecting member, a slide reciprocally mounted on the support and engageable with the projecting member of the breech bolt, a lever plvotally

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