US2711041A - Extractor for firearms - Google Patents

Description

June 21, 1955 E. M. HARVEY EXTRACTOR FOR FIREARMS Original Filed Feb. ll, 19449 87 857g; f/@7 lll (MU F 'i J6) ggg w M ww United States Patent-O (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described in the specification and claims may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to firearms having a longitudinally reciprocating bolt and more particularly to a superior cartridge extractor associated therewith.

The present application constitutes a division of my copending application Serial No. 75,921, tiled February` An object of this invention is to provide a simple and sturdy firearm extractor which can be readily assembled and disassembled from a bolt without the use of any tools.

A further object of this invention is the provision of a replaceable rearm extractor which cannot be accidentally separated from a reciprocating bolt in the event of excessive gas pressure at the breech upon the occurrence of a blown primer or ruptured cartridge case.

A specific object of the present invention is the provision of a firearm extractor which will maintain a positive engagement with the rim of a cartridge case despite the accumulation of excessive amounts of dirt or other foreign matter at the firearm breech.

The specific 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. l is a cross-sectional longitudinal view of a bolt assembly incorporating the extractor of this invention;

Fig. 2 is a top view of the extractor receiving portion v of the bolt shown in Fig. 1;

Fig. 3 is an enlarged perspective view of the extractor; Fig. 4 is a front end view of the bolt showingthe extractor fully seated therein; and

Fig. 5 is a fragmentary cross-sectional view the extractor in the act of riding over the rim of a Chamfbered cartridge as the bolt moves into battery position. There is illustrated in Fig. l, a bolt 55 having av locking block 56 pivotally mounted thereto and arranged to function in a manner fully described in the aforesaid copending application. Bolt 55 and locking block' 56 reciprocate longitudinally within a receiver having a cartridge ejection opening 5 at the top thereof. A barrel '51 is conventionally secured to the forward end ofreceiver 50. The face of bolt is provided with an interrupted annular flange 6 defining a cartridge seating recess 68 adapted to snugly receive the base of a cartridge case 69. A cartridge ejector 73 is slidably mounted in bolt 55 parallel to and below the longitudinal central axis thereof. The front tip of ejector 73 normally projects into cartridge seating recess 68 to abut the base of cartridge case 69. A spring 75 is retained within bolt 55 as by a plug 76 secured by a transverse pin 66 and biases ejector 73 forwardly to dislodge cartridge case 69 from recess 68 and eject such case out through receiver opening 5.

On the forward end of bolt 55 there is provided a subshowing stantially U-shaped recess 78 communicating with recess 68. Centrally of recess 78 there is formed a U-shaped groove 82 concentrically located with respect to recess 78. The opposite sides of groove 82 extend transversely of recess 78 as best indicated in Fig. 2. Moreover, the entire groove 82 is slightly tilted with respect to the vertical axis of recess 78 so that the aforesaid sides are inclined upwardly and rearwardly from the vertical for a purpose to be described.

Extending rearwardly from bolt recess 78 is a longitudinal counterbored hole 86. A plunger 7 is slidably mounted in hole 86 and comprises a stem 85 and a cylindrical head 8 of greater diameter than stem 85. A spring 87 surrounds stem 85 and is arranged to seat within the counterbored portion of hole 86 so as to normally bias plunger head 8 forwardly. Plunger head 8 terminates in a V-shaped front end 84.

Slidably mounted in bolt recess 76 is an extractor 79 comprising a U-shaped body portion 9 and a claw 80 projecting forwardly therefrom. Body portion 9 is exteriorly provided with a U-shaped rib 81 inclined to correspond with groove 82 and arranged to slidably mate therewith when extractor 79 is assembled into bolt recess 78. The rear end of extractor body portion 9 is provided with a V-shaped cut 83 arranged to matingly receive the correspondingly formed plunger head 8. Claw is arcuately formed and stepped down relative to the top of body portion 9. In order to positively grip the rim of cartridge case 69, claw 80 is undercut as indicated at 10 andthe lower front edge thereof is beveled as shown at 11 to correspond with the forwardly inclined shoulder forming the conventional extractor groove in cartridge case 69. When extractor 79 is fully seated within bolt recess 78, claw 80 serves to complete the annular configuration of ange 6.

Upon the discharge of a round, locking block 56 is cammed out of locking engagement with receiver 50 by a conventional operating rod whereupon both bolt 55 and locking block 56 recoil to the rear of the lirearm. Since the rim of the fired cartridge case 69 is gripped by claw 80 when bolt 55 is in locked battery position, extractor 79 operates to withdraw the cartridge case 69 from the chamber of barrel 51. Upon complete withdrawal therefrom, the forwardly biased ejector 73 causes cartridge case 69 to pivot about claw 80 as a fulcrum and be ejected upwardly out of the firearm through receiver opening 5. In the event extractor 79 is not completely seated in bolt recess 78 during recoil of bolt 55 because of dirt or other foreign matter in such recess, the angular inclination of rib 81 and groove 82 will tend to force extractor 79 downwardly in bolt recess 78. The greater the resistance to extraction offered by cartridge case 69, the greater will be such seating tendency. VHowever, should the foreign matter be such as to still leave portion 9 projecting above the top surface of bolt 55, there is provided on the rear wall of receiver opening 5 an angular cam surface 12 arranged to be contacted by a similar cam surface 13 at the top rear edge of extractor body portion 9. Thus, extractor 79 will be forced into positive seating engagement in bolt recess 78 and thereby always be in position to rmly engage the rim of cartridge case 69 upon the conclusion of the counter-recoil movement of bolt 55.

At such time, the beveled portion 11 of extractor claw 80v will forcibly contact the base of cartridge case 69 whereupon extractor 79 will be cammed vertically upward as rib 81 slides in groove 82. This upward movement of extractor 79 forces plunger 7 rearwardly against the bias of spring 87 due to the angular mating surfaces in plunger front end 84 and extractor cut 83. As a result, suflicient energy is stored up in spring 87 so that when claw 80 rides over the rim of cartridge Case 69 at the ing block 56 limits the rearward movement of plunger 7 which, in turn, arrests the upward vertical movement of extractor 79. As a result of such structure, extractor 79 can not separate from bolt 55 as long as locking block 56' is mounted thereto. Thus, eveny if a blown primer or ruptured cartridge case permits the high pressure gases into the barrel chamber to act upon extractor 79, there will be no danger of accidental separation thereof from bolt 55. Furthermore, in the event that the prssure lis so great as to break plunger stem 85, the possible separation of extractor 79 from bolt 55 will be prevented by the upper wall surface 99 of receiver 50 which lies directly above claw 80 when bolt 55 is in battery position. Moreover, whether plunger 7 or surface 99 halts the upward movement of extractor 79, cam surface 13 will still be in longitudinal mating alignment with cam surface 12. Such construction eliminates the possibility of serious jamming of the gun which could occur if cam surface 13 were to strike the rear wall of cartridge ejection opening 5 above cam surface 12 during recoil movement of bolt 55.

To disassemble extractor 79 from boltl 55y it is, of course, rst necessary to remove bolt 55 and locking block 56 from receiver 50. Then when locking block A56 is disassociated from bolt S5, the nose of a cartridge or similar means can be employed to pry extractor 79 out of engagement with plunger 7 for removal from bolt 55. To reassemble, plunger 7 and spring 87 are inserted into counterbored hole 86 and extractor 79 is placed into bolt recess 78 with rib 81 engaging groove 82. Then by employing sufficient pressure on extractor 79, plunger 7 will be forced rearwardly out of the path of body portion 9. Accordingly as extractor 79 isv further forced downwardly into recess 78 by suitable means, plunger 7 will engage in V-shaped cut 83 as previously explained. Then bolt 55 and locking-block 56 are assembled into receiver 50V whereupon the resulting limited movement of plunger 7 prevents disengagement of extractor 79 therefrom.

I claim:

l. In a firearm having a receiver, a bolt longitudinally reciprocable in the receiver between a recoil and a battery position, and a locking block pivotally mounted to the bolt for movement between a raised locked position and a longitudinal unlocked position, the combination of, an extractor having a body portion and a forwardly pro'- jecting claw portion, there being a recess in the front end of the bolt for slidably receiving said extractor and a longitudinally disposed counterbored hole extending rearwardly from said. recess, the locking block being disposed so as to obstruct the rear end of said counterbored hole when the bolt lies within the receiver, a plunger horizontally mounted in said counterbored hole for limited reciprocal movement, said plunger having a V-shaped head portion and a rearwardly extending stem portion, said extractor body portion having a V-shaped eut at the rear end thereof, and spring means for biasing said plunger head portion into mating engagement with said cut in said exterior body portion, all constructed and arranged whereby separation of said extractor vfrom thev bolt can be eiected only when the locking block isvdi`sassembled therefrom.

. 2. In a firearm, the combination of a longitudinally reciprocable bolt having a vertically disposed extractor recess in the forward top portion thereof and an upwardly extending, rearwardly sloping U-shaped groove formed into the walls of said recess, a cartridge case extractor having a rearwardly sloping U-shaped rib about the exterior thereof, said extractor being mounted in said recess with said rib thereon slidably engaged in said groove whereby the longitudinal pull necessary to overcome the frictional resistance to extraction of a tired cartridge case cams said extractor vertically downward to fully seat in said bolt recess, a spring-biased plunger reciproeably mounted in said bolt rearwardly of said extractor for movement substantially perpendicular to the path of extractor movement, said plunger having a substantially V-shaped head portion, said extractor having a V-shaped recess in the rear end thereof engageable by said plunger head portion whereby said plunger yieldingly urges said extractor into full seating engagement in said recess in said bolt, and means for limiting rearward movement of said plunger to prevent disengagement between said plunger head portion and said extractor V- shaped recess thereby retaining said extractor in said bolt.

3. In a firearm, the combination of a receiver having a cartridge case ejection opening in the top thereof, a bolt slidably mounted iny said receiver for longitudinal reciprocal movement between a battery and recoil position, said bolt having a vertically disposed extractor recess in the forward top portion thereof and an upwardly extending, rearwardly sloping U-shaped groove formed into the walls of said recess, a cartridge case extractor having a rearwardly sloping U-shaped rib about the exterior thereof, said extractor being mounted for substantially vertical movement in said bolt recess with said rib thereon in slidable engagement with said groove, a plunger reciproeably mounted in said bolt rearwardly of said extractor for movement substantially perpendicular to the path of extractor movement, said plunger having a substantially V-shaped head portion, vsaid extractor having a V-shaped recess in the rear end thereof engageable by said plunger head portion, spring means normally biasing said plunger forwardly whereby said head portion cams said extractor vertically downward to fully seat in said bolt recess with the top surface of said extractor substantially aligned with the top `surface of said bolt, said extractor having a forwardly sloping angular surface on the rear end thereof above said V-shaped recess, and a mating angular surfacel on theY rear end wall defined by said cartridge ejection opening in said receiver operative on said extractor angular surface during recoil movement of said bolt to c'atn said extractor into full seating engagement in said bolt'recess in the event said plunger fails to prevent said extractor from protruding beyond the top surface of said bolt.

References Cited in the file of this patent UNITED STATES PATENTS

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