US2929163A - Retention means for firearm extractor - Google Patents

Description

March 22, 1960 E. M. HARVEY 2,929,163

RETENTION MEANS FOR FIREARM EXTRACTOR Filed Dec. 23. 1958 Figll- INVENTOR. Earle M Harvey U e air-S Pateh iic V r 2,929,163 r I i RETENTION MEANS FOR FIREARM EXTRACIOR Earle M. Harvey, Agawam, Mass., assignorto the United States of America as represented by the Secretary or.

The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any;royalty thereon.

This invention relates to means for-[extracting fired Cartridge cases from thefiringchamber in firearms having a reciprocating bolt and is more particularly directed to a self-contained extractor assembly releasably mounted in 'such bolt. v

Cartridge case extractors generallyconsist of several components which, when disassembled from the firearm bolt, results in the"si multancous disassembly of the ex- 2,929,163 Patented Mar. 22, 1960 il-lig. 6 is an enlarged exploded view of the complete extractor assembly in perspective.

Referring to the drawings in which like numerals designate like parts, there is disclosed the forward portion of a 'firearm bolt 10 having assembledthereto an extractor 28. The front face of the bolt 10 is cylindrically recessed. as shown at 12, to receive the base of a cartridge case 14. A longitudinally disposed firing pin hole 16 is provided in bolt 10 and is of suitable configuration to receive a firing'pin (not shown) arranged to project into recess 12. v

At the top of bolt 10 is a rectangular slot 18 which extends rearwardly from the face of the bolt 10. The rear wall of slot-18 slopes rearwardly and downwardly to terminatejjin a semicylindrical transverse groove 20 arranged ,to' rotatably receive oppositely disposed lugs 64 tractor itself thereby introducing the, possibility of losing these component parts and rendering the extractor useless. tors requires the removal of onerof the components of the firearm bolt or the utilizationjof a separate tool; In some instances, extractors are of one-piece construction but these have also proved to be unsatisfactory due to the fact that they are not too rugged and cannot withstand the severe stresses imposed upon them in high-speed automatic firearms.

These'disadvantages are overcome by the present in- V vention which provides a compact unit which can be use of a tool .or the removal of any other component'ofthe bolt. Furthermore, once the extractor is fdisassembled from the firearm bolt all the components are retained as a completeassembly thereby eliminating'the loss of any parts.

It is anobject of this invention to provide a cartridge case extractor for a firearm which can be releasably mounted in a reciprocating bolt and readily disassembled therefrom as a complete unit.

Anotherobject of this invention is to provide a cartridge case extractor in a firearm bolt wherein the retention therein is accomplished by ball and socket means.

A specific object of my invention is to provide a simple, solid, and rugged cartridge case extractor capable of withstanding the severe stresses encountered in the operation of high-speed automatic firearms.

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

Fig. 1 is a fragmentaryjview of the firearm bolt par tially in cross section to show the extractor mounted therein;

Fig. 2 is a cross-section view taken on line 2--2 of Fig. 1 showing the ball means for retaining the extractor in the bolt;

Fig. 3 is a fragmentary view along line 33 of Fig. 2 showing the extractor receiving slot in the top of the bolt;

Fig. 4 is a cross-section view taken along line 4-4 of Fig. 1;

retaining means therefor omitted; and

Furthermore, thedisassembly of prior art extrac- 1 projecting outwardly from the rear end of extractor28. The opposite sidewalls of slot 18 are each provided withra pear-shaped'depression 22'having a substantially hemispherical lower portion 24 and an inwardly inclined On the underside of body portion 30 of extractor 28 t is a if-shaped undercut 38 the rearward portion 40 being smaller in width than the forward portion 42 thereof. Iherearward and forward portions of undercut 38 are ar'cuately 'joined as shown at 44.

he body portion 30 ofextractor 28 is provided with a transverse hole 46 which intersects the forward portion 42 of undercut 38 as shown at 48 The outer'ends of hole"46 are slightly reduced in diameter by being 'peened 38, the narrow portion 52 of spring50 resting within the rearward portion. 40 of undercut 38 and the forward portion 54 of-spring 50 similarly disposed in portion 42-of undercut 38 with the curved portions 56 therein resting against the arcuate portions 44 of undercut 38. The forward end of spring 50 beyond curved portions 56 is' reversely curved to form concave portions and finally terminates in outwardly curved ends 58 arranged to abut the sidewalls of undercut 38 as best shown in Fig. 2.

A ball 62 slightly smaller than the diameter of hole 46 is slidably and rotatably seated in each end thereof to contact the concave portion 60 of spring 50. Peened portions 47 serve as a stop means for retaining balls, 62

Lin hole 46 under the pressure imparted thereto by spring 5 50. A portion of the periphery of each ball 62 extends through hole 46 to seat within the hemispherical-portion 24 of depression 22 in bolt 10.

During feeding of a cartridge into the firing chamber of the firearm, extractor claw 32 is pivoted outwardly relative to bolt'ltl by the cartridge case rim as the bolt moves forwardly into battery position. As extractor 28 is pivoted outwardly, extractor spring 50 is compressed by balls 62 which are moved upwardly along cam portions 26 of pear-shaped depression 22 in bolt 10. When extractor claw 32 rides over the rim of the cartridge case 14 and engages in extractor groove 34, spring 50 is free to return to the normal position thereof and consequently the interaction between balls 62 and the inwardly inclined cam portions 26 of pear-shaped-depression 22 return balls 62 into the hemispherical portions 24.

Thus, there is here provided a cartridge case extractor which can be readily disassembled from a bolt by merely exerting manual pressure upwardly and outwardly against the forward portion of the extractor until the balls 62 are disengaged from the pear-shaped depression 22-. As a result the removal of the extractor is accomplished without the use of any tool or the disassembly of any parts of either the bolt or the extractor. Furthermore, once the extractor has been removed from the bolt it consists of a self-contained unit which prevents the possibility of losing any of the component parts.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim: 7

1. In a firearmhaving a longitudinally reciprocal bolt, a removable extractor pivotally mounted in the top of the bolt comprising a body portion having a claw at the forward end thereof for engaging in the extractor groove of a chambered cartridge case at'the conclusion of the for ward movement of the bolt, a ball rotatably disposed in each of the opposite sidewalls of said body portion, stop means in said body portion for preventing the outward removal of said balls therefrom during disassembly of said extractor from the bolt, spring means biasing said balls against said stop means whereby a portion of the periphery of each of said balls protrudes outwardly beyond the respective sidewall of said body portion, a pair of depressions in the bolt straddling said body portion is position to releasably receive the respective pro truding peripheral portions of said balls, and inwardly inclined cam surfaces in said depressions for forcing said balls to compress said spring means and thereby limit the extent of the outward pivotal movement imparted to the forwardly moving extractor through the contact of said i claw with the rear end of the cartridge case whereby the resulting pressure of said balls against said cam surfaces insures thereturn of said extractor to the unpivoted position thereof for entry of said claw into the extractor groove of the cartridge case.

2. The invention according to claim 1 wherein each of said depressions are provided with a hemispherical portion concentric with the periphery of said balls and said inclined cam surfaces extend upwardly and inwardly from said hemispherical portions.

3. In a firearm having a longitudinally reciprocal bolt from the front face thereof and terminating in a semicylindrical groove at the junction of the bottom and rear walls thereof, an extractor releasably mounted in the rectangular slot comprising a body portion having a claw at the forward end thereoffor engaging in the extractor groove of a chambered cartridge case at the conclusion ofthe forward movement of the bolt, lug means projecting from opposite sides of said extractor to engage in the semicylindrical groove and pivotally mount said extractor in the bolt, said extractor having a T-shaped undercut extending longitudinally along the bottom thereof, a transverse hole intersecting the forward portion of said undercut, a ball rotatably disposed in each end of said hole, said transverse hole being of lesser diameter at each end to form stop means for preventing the outward removal of said balls therefrom during disassembly of said extractor from the bolt, a compression spring in said transverse hole for biasing said balls against said stop means whereby a portion of the periphery of said balls protrudes outwardly beyond the opposite sidewalls of said extractor body portion, a pair of oppositely disposed, pear-shaped depressions formed in the sidewalls of the longitudinal slot in the bolt, said depressions comprising a substantially hemispherical lower portion for respectively receiving the protruding peripheries of said balls and an inwardly inclined cam surface extending upwardly from said hemispherical portion whereby said cam surfaces force said balls inwardly to compress said spring and thereby limit the extent of the outward pivotal movement imparted to the forwardly moving extractor through the contact of said claw with the rear end of the cartridge case so that the resulting pressure of said balls against said cam surfaces insures the return of said extractor to the unpivoted position thereof for entry of said claw into the extractor groove in the cartridge case.

' 4. The combination defined in claim 3 wherein the forward portion of said T-shaped undercut is of greater width than the rearward portion thereof and is joined thereto by arcuate sections, and said compression spring is of hairpin configuration to resiliently fit into said undercut, said spring having outwardly curved ends adapted to "form arcuate portions for receiving the peripheral portions of .said balls protruding from said transverse hole.

No references cited.

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