US2350821A - Bolt closer for automatic arms - Google Patents

Description

June e, 1944. G IRvELLI 2,350,821

BOLT CLOSER FOR AUTOMATIC ARMS Filed Dec. l2, 1939 2 Sheets-Sheet l June 6, 1944. G, REvELLl l 2,350,821

BOLT CLOSER FOR AUTOMATICARMS Filed DSC. 12, 1959 2 Sheets-Sheet 2 14?@ f /4 g :l r G Patented June 6, 1944 BOLT CLOSER FOR AUTOMATIC ARMS Gino Revelli, Rome, Italy; vested in the Alien Propertyl Custodian In Italy December 21, 1938 Application December 12, 1939, Serial No. 308,845

2 Claims.

This invention relates to an improved breech block operating means for automatic rearms and has for its object the provision of means permitting the retraction of the breech block at a relatively low .pressure thereby resulting in reduction of friction, wear of the parts and strain to which the parts are subjected.

The invention relates to a rearm of the type wherein a breech block casing or barrel extension is locked to the breech block for a short portion of the recoil stroke; the barrel and breech block moving backward together during such portion of the recoil.

The invention consists in an improved automatic firearm of the type referred to, characterized in that the barrel extension and breech block are locked together by an oscillating pawl one end of which seats in a recessed part of a barrel extension while the other end engages in a notch in the block, the said pawl being locked in engaging position by one arm of a bell crank lever, the other arm of which engages a fixed stop during the recoil stroke.

The invention further consists in providing the pawl with a downwardly extending part designed to engage the first mentioned arm of the bell crank lever only when said lever has completed a predetermined angular movement.

Other objects of my invention will appear from the following description taken in connection with the accompanying drawings wherein,

Fig. 1 is a partial longitudinal sectional View, partly in elevation; of a portable rifle, with a cartridge in the barrel, blocked therein by the bolt or breech block and with the striker cocked ready for firing.

Fig. 2 is a similar view with the parts in the position they assume during the extraction of the cartride case.

Fig. 3 is a similar view with the parts in the position they assume after firing and extraction of the cartridge case.

Figs. 4 and 5 are enlarged detail views of portions of the structure shown in Figs. l and 2 respectively.

Referring to Fig. 1, the barrel I is screwed to the breech casing 2 and held in the position shown by a spring 23. Against the back of the barrel I bears the breech block or bolt 3 held in this position by a pawl 4, the forward portion 5 of which as shown in Fig. 1 is seated in a recess 6 in the under surface of the bolt 3. Inside the Abolt 3 is the striker l which is adapted to be actu- :the rod 8.

The rear surface 9 of the pawl 4 is cylindrical and is seated in a recess' I0 in the movable breech casing, the pawl being adapted to turn in seat from the positionV shown in Fig. 1 to that 'sho-wn in Fig. 2. The pawl is formed with a downward extending curved portion II adapted to co-operate with the upper arm I2 of a bell crank lever I2--I3 pivoted at I4. In the blocked position shown in Fig. 1, the lever I2-I3 holds with the end of its arm I2 the blocking pawl 4 in the recess 6, this arm I2 engaging the lower surface I5 of the pawl. The lever I2-I3 is biased to the position shown in Fig. 1 by a spring I6.

At the instant of firing the case Il reacts against the bolt 3 moving it and its contained striker backward and due to the locking action of the pawl 4, the barrel and bolt move backward as a unit. Due to the relatively great mass of the barrel, barrel extension and bolt this initial backward movement is comparatively slow with the result that an increased speed of the bullet is obtained.

After a certain distance is traversed in the recoil movement, arm I3 of lever I2-I3 engages against the xed stop I8 and moves the lever in a counter-clockwise direction against the action of the spring I6. The end of the arm I2 slides on the surface I5 of the -pawl 4, then leaving the surface enters the notch I9 between the pawl proper and the extension II. The arm I2 then engages the upper surface of the extension Il and lowers the latter and pawl. This lowering movement is progressively accelerated `since the initial engagement of arm I2 and extension Il is between the inner part of arm I2 and the outer end of the extension and later the outer end of the arm engages the inner portion of the extension.

When the locking pawl 4 has left the seat 6 in the under surface of the bolt 3 the latter, together with the striker due to the reaction of the shell case Il, moves backward independently of the breech block casing and through rod 8 compresses the thrust spring, and assumes the position shown in Fig. 3.

Starting from the position shown in Fig. 3 the bolt 3 is pushed forward by the thrust spring acting through the rod 8 and in such movement engages the upper cartridge 2l of the magazine and thrusts it into the chamber 23. The advance of the bolt and the striker take `place together until the back of the tooth 24 of the striker engages the seat 25. The striker is then stopped in its advance while the bolt continues due to inertia, thrusting the cartridge into the appropriate space in the'barrel. The parts are now returned to the position shown in Fig. 1.

To prevent impinging of the striker against formed with a recess, a bolthaving a notch in its surface, anoscillating pawl, one end of which is pivotally mounted in said recess, and the other end which is adapted to engage in said notch to lockjsaid extension and bolt together, a bell crank lever pivoted on and movable with said extension,

one arm of said lever being constructed and arranged to `engage said `pavvltolock the same in 'locked position, a fixed stop `'adapted'to engage l2-I3 is returned to the yposition of Fig. 1 any untimely movement of the trigger ,29 cannotiire the cartridgeV becausethe striker is held back kby engagement of the end 28 ofnthesafety lever i engaging the tooth 24. i A spring V32 urges the safety-lever 26toa position for engagement With the tooth AZlio-n the iffor, v

ward movement of the bolt. The parts are so proportioned that the lowering of the lever 2-6v takes -place at the instant Whenipawl ,d engages 'in the notch 3 of the ,b olt"6.

YHaving now described my invention. what'l claim and desire `1to `s'ecurby LettersPatent is:

1. An automatic 'firearm `comprising a barrel Y having a rear 'extension rigid therewith land` the 'other arm of said lever during recoil vInove- Jment, said pawl being formed with a downward extension adapted to be engaged by said i'lrst `namedarrn whensaid lever has completed a predetermined angular movement, to remove said .pawl from vsaid Anotch and means biasing said lever and pawl to( locking position.

`l2. The y.iirearrnasc1aimed in claim 1 wherein itifielboltlis provided With a striker, and an automatic-safety lever is pivotally mounted on said extension biased to position to lock said striker and :actuated by said `bellicrank lever 4to unlock saidstrikerwhen saidibolt isllocked-to said barrel extension.

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