US3733729A

US3733729A - Shell extractor for firearm with falling breechblock

Info

Publication number: US3733729A
Application number: US00217614A
Authority: US
Inventors: R Baker
Original assignee: COLT IND OP CORP
Current assignee: CFPI Inc A CORP OF; COLT LICENSING A DE Ltd PARTNERSHIP LP; CII Holdings Inc
Priority date: 1972-01-12
Filing date: 1972-01-12
Publication date: 1973-05-22
Anticipated expiration: 1990-05-22

Abstract

A firearm with a falling breechblock has a shell extractor loosely mounted upon a pivot structure in the receiver for pivoting movement between a first position and a second position, and for lateral tilting motion. The shell extractor occupies the first position in which it is adapted to engage the periphery of a chambered cartridge when the breechblock occupies its battery position. The shell extractor occupies its second position free from engagement with the periphery of the cartridge when the breechblock is in its retracted position. A cam arrangement is employed to tilt the extractor away from engagement with the cartridge during pivoting movement of the extractor from the first position to the second position so as to permit complete withdrawal of the cartridge from the chamber and subsequent insertion of a new cartridge. The cam arrangement may be adjusted to vary the tilt of the shell extractor in the second position so as to allow for a wider latitude in tolerances.

Description

United States Patent [191 Baker 1 May 22,1973

[54] SHELL EXTRACTOR FOR FIREARM WITH FALLING BREECHBLOCK 75] Inventor: Richard L. Baker, Hartford, Conn.

[73 Assignee: Colt Industries Operating Corp.,

Hartford, Conn.

[22] Filed: Jan. 12, 1972 [21] Appl. No.: 217,614

[52] US. Cl. ..42/23 [51] Int. Cl ..F4lc 15/08, F4lc 11/04 [58] Field of Search ..42/23, 24, 14

[56] References Cited UNITED STATES PATENTS 3,355,833 12/1967 Ruger et al. ..42/23 3,621,596 11/1971 Colliander et al. ..42/23 Primary Examiner-Samuel F einberg Assistant ExaminerC. T. Jordan Att0mey-Radford W. Luther et a1.

tractor loosely mounted upon a pivot structure in the receiver for pivoting movement between a first position and a second position, and for lateral tilting mo- 1 tion. The shell extractor occupies the first position in which it is adapted to engage the periphery of a chambered cartridge when the breechblock occupies its battery position. The shell extractor occupies its second position free from engagement with the periphery of the cartridge when the breechblock is in its retracted position. A cam arrangement is employed to tilt the extractor away from engagement with the cartridge during pivoting movement of the extractor from the first position to the second position so as to permit complete withdrawal of the cartridge from the chamber and subsequent insertion of a new cartridge. The cam arrangement may be adjusted to vary the tilt of the shell extractor in the second position so as to allow for a wider latitude in tolerances.

PATENTEUMYZZ 197s SHEET 1 [1F 2 mum FIGJ

2 a G. I n. w P

PAIENIEUMAY 22 I973 SHEET 2 BF 2 SHELL EXTRACTOR FOR FIREARM WITH FALLING BREECHBLOCK BACKGROUND OF THE INVENTION The invention relates generally to shell extractors for firearms, and more particularly to shell extractors for firearms having falling breechblocks which are adapted to use rimless cartridges or belted cartridges.

In the past, firearms incorporating falling breechblocks have included shell extractors loosely mounted upon pivot structures in the receiver for lateral tilting motion away from a chambered cartridge (which may be a rimless or belted cartridge) which they are adapted to extract during falling movement of the breechblock. Such tilting motion of the extractor during retraction of the breechblock has been occasioned by a cam surface on the breechblock, itself, adapted to engage the extractor during falling movement. While such an arrangement yields satisfactory operation, it is disadvantageous from the manufacturing standpoint, since fairly narrow tolerances must be adhered to if the extractor is to function properly. In addition, such an arrangement further complicates the construction of the breechblock.

SUMMARY OF THE INVENTION The invention contemplates a shell extractor arrangement for a firearm having a falling breechblock, wherein cam means are provided to tilt the extractor away from engagement with a rimless or belted cartridge during pivoting movement of the extractor from a first position to a second position as falling movement of the breechblock progresses. In accordance with the invention, means are furnished to adjust the cam means to vary the tilt of the extractor in the second position, to thereby allow for a wider latitude in tolerancing. The cam means and the adjusting means are not associated with the breechblock so as to require the provision of cam surfaces thereupon.

Succinctly stated, in a preferred embodiment, an abutment member is mounted in a receiver adjacent a shell extractor having a cam surface thereupon adapted to be contacted by the abutment member during pivoting movement of the lever when the breechblock is lowered from its battery position to its retracted position. The abutment is constituted by the tip of a screw threadably inserted in the receiver and capable of external adjustment so that with respect to the shell extractor, tolerances are not as critical as they are in the type of firearm discussed hereinabove.

Accordingly, it is a primary object of the invention to provide a firearm with a shell extractor arrangement which permits increased tolerances in the firearm and thereby facilitates its manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a fragmentary, side elevational view, partly in section, of a firearm incorporating a shell extractor arrangement according to the invention.

FIG. 2 is a view, similar to that of FIG. 1, showing the breechblock in the lowered position.

FIG. 3 is a rear elevational view, partly in section, of the shell extractor, per se.

FIG. 4 is a top view of the shell extractor of FIG. 3 taken along the line '4-4.

FIG. 5 is a side elevational view of the shell extractor, per se, taken along the line S5 of FIG. 3.

' 2 FIG. 6 is a sectional view of the hook of the s hell extractor taken along the line 66 of FIG. 3.

FIG. 7 is a fragmentary, transverse sectional view of i the firearm of FIG. l-taken along the line 77, showing the relationship between the abutment, the re- 7 ceiver, and the cam surface on the shell extractor.

FIG. 7a is a fragmentary view along the line 7 a7b of FIG. 2, showing the abutment engaging the cam sur face of the shell extractor.

FIG. 8 is a transverse sectional view of the firearm of FIG. 1 taken along the line 88.

FIG. 9 is a schematic view showing the cocking lever maintained in an extended position by the spring loader plunger in the receiver.

FIG. 10 is a top plan view of the..breechblock, per se.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Turning now to FIG. 1, there is shown a firearm having a falling breechblock 12 mounted within a passage 14 of a receiver, generally shown at 16. A barrel 18, having a chamber 20, is threadably secured to the receiver such that the chamber 20 communicates with the passage 14. A belted cartridge 22, inserted in the chamber 20, is adapted to be contacted by-a firing pin (not shown) carried in the front of the breechblock 12 when the breechblock is in the upper or battery position, as illustrated in FIG. 1. When the breechblock I2 is lowered from its battery position of FIG. l'to its lower or retracted position of FIG. 2, a shell extractor arrangement, generally shown at 24 in FIG. 1, effects a withdrawal of the cartridge 22 from the chamber 20. This withdrawal may be either partial or complete, depending upon whether the breechblock 12 is lowered rapidly or slowly. If the breechblock 12 is lowered slowly, the cartridge 22 will only be partially extracted from the chamber 20 and complete extraction must be accomplished by manual means, such as a user's fingers.

The shell extractor arrangement 24 includes an extractor 26 constituted by an upper arm 28, a hub portion 30, and a lower arm 32. The hub portion 30 ofthe extractor 26 comprises a passage 34 which is adapted to loosely receive a mounting pin 36 to support the extractor 26 for pivoting movement between a first position, illustrated in FIG. 1, and a second position, illustrated in FIG. 2, and lateral tilting movement. Rearward pivoting of the extractor 26 between the first position of FIG. 1 and the second position of FIG. 2 is accomplished by means of a cylindrical projection38 laterally extending from a side of the breechblock, the projection 38 being positioned intermediate the front and rear faces of the breechblock 12, and a surface 40a which partially defines a recessed portion of the side of the breechblock 12 in which the projection lies. When the breechblock is lowered to its retracted position, the projection 38 first contacts the extractor 26, to exert a large extraction force upon cartridge 22, and subsequently the surface 400 contacts the extractor 26 to increase the rate of extraction, as is explained hereinafter.

Turning now to FIGS. 3 through 6, wherein the detailed construction of the shell extractor 26 is illustrated, it can be seen from FIG. 3 that the passage 34 in the hub portion 30 of the shell extractor 26 is formed by a large bore 34a and a small bore 34b, the small bore 34b being slightly larger in diameter (e.g., 0.005 inch) than the pin 36 which it envelops so that the extractor 26 is capable of lateral tilting motion in the receiver. Formed on the extremity of upper leg 28 of extractor 26 is a cartridge hook 42 which is adapted to engage an annular groove 22a on the periphery of the cartridge 22, the cartridge 22 being shown in phantom in FIG. 3. The hub 30 of the extractor 26 has

vertical sides

44 and 46 and bevelled

sides

48 and 50, the

sides

44 and 48 defining the right side of hub portion 30, and the

sides

46 and 50 defining the left side of hub portion 30. It will be noted from FIG. 3 that the bevelled

sides

48 and 50 intersect the respective

vertical sides

44 and 46 approximately mid-way of the passage 34.

Further details of the geometry of extractor 26 will be evident from FIG. 4. From FIG. 4, it can be seen that the lower leg 32, which is acted upon by the breechblock 12 during the lowering thereof to the retracted position, is of a small width compared to the overall width of the extractor 26. The lower leg 32 must necessarily be of a relatively small width because it is adapted to be almost totally received within the recess 40 in the side of the breechblock 12.

Referring to FIG. 4 in conjunction with FIG. 5, it can be seen that the top surface of the leg 32 is defined by an inboard surface 52 and an outboard surface 54. When breechblock 12 is lowered to the retracted position to extract cartridge 22, the projection 38 on the breechblock 12 initially contacts the outboard surface 54 to provide a significant mechanical advantage (which may be necessary if cartridge 22 is jammed in chamber during the initial portion of the extraction process to dislodge cartridge 22. Subsequently, surface 40a engages inboard surface 52 of leg 32 to increase the pivoting speed of the extractor 26, and hence the rate of cartridge extraction, for a given downward velocity of the breechblock 12. Obviously, increasing the pivoting speed of the extractor 26 in such a manner results in a penalty to the extraction force asserted by hook 42 on the cartridge 22. But, it will be appreciated that a large extraction force is only necessary during the initial phase of extraction to overcome the initial resistance to displacement offered by a chambered cartridge. Once the chambered cartridge has been loosened by the initial force applied thereto by extractor hook 42, a minimal additional force is normally required to complete the extraction of cartridge 22. Also, it will be noted that the small bore 34b is on the same side (i.e., the right side) of the extractor 26 as is the leg 32 so that there is no tendency to tilt the extractor 26 away from the cartridge 22 during initial extraction.

The extractor hook 42 includes a projection 42a having a radius of curvature approximating that of a cartridge which it is to extract. Projection 42a is defined by a contoured front surface 42b on the hook 42, and an engagement surface 42c. The engagement surface 42c is adapted to exert a rearward pulling force on the periphery ofa cartridge during rearward pivoting of the extractor 26; and the contoured surface 42b is adapted to coact with the rear of a newly inserted cartridge as the breechblock 12 is moved into the battery position to produce an outward lateral titling movement of the extractor sufficient to permit the projection 42a to snap into the groove 22a as the breechblock l2 assumes its battery position. The surface 420 is spaced forwardly of rear face 42fof the hook 42 a distance sufficient to cause the projection 42a to be received within the groove 22a when the face 42f abuts front face 120 of the breechblock 12. As shown in FIGS. 3 and 5, the undersurface of the hook 42 is constituted by a horizontal forward surface 42d, and an inclined rear surface 42e, both of which engage the breechblock 12, in a manner hereinafter explained, when the breechblock 12 is moved to the battery position.

As best shown in FIGS. 1, 2 and 7, the right side of the hub portion 30 is provided with a cavity 56 bounded by laterally and vertically extending cam surface 58, shaped as a triangle. As the extractor 26 pivots between its first position and second position, an abutment 60, mounted in the receiver 16, is adapted to engage the cam surface 58 to exert a force on the extractor tending to laterally tilt the extractor outwardly such that book 42 moves out of engagement with the periphery of a cartridge which is being extracted. Abutment 60 comes into contact with the cam surface 58 only during the latter part of the rearward pivoting movement of the extractor, that is, just before the extractor assumes its second position.

As shown in FIG. 7, the abutment 60 is constituted by the tip of an Allen screw 62 threadably inserted into a bore 64 in the receiver 16. The outboard end of Allen screw 62 is provided with the usual hexagonal socket for reception of a suitable tool for turning the screw. Hence, the amount of tilt imparted to the extractor 26 may be varied by adjustment of the Allen screw 62. Such an adjustment will also establish the angle through which the extractor 26 must pivot between its first position and its second position before contact is achieved between abutment 60 and cam surface 58. The Allen screw 62 of FIG. 7 is shown in phantom in FIGS. 1 and 2; and it will be noted that in FIG. 1, the abutment 60 is spaced from the cam surface 58, but is received within the recess 56.

The manner of mounting the extractor 26 upon the pin 36 is shown in FIG. 8. The pin 36 also serves as the mounting structure for a cocking lever 66 which is appropriately connected to the breechblock 12 so that movement of the lever from a retracted position to an extended position lowers the breechblock 12 from the battery position to the retracted position and also cocks the firing mechanism therein. Since the structural Cooperative relationship between the breechblock l2 and the cocking lever 66 forms no part of this invention, it will not be discussed herein, except to the extent necessary to describe the present invention. It should be noted however, that the relationship between the cocking lever 66 and the breechblock 12 is fully shown and set forth in U.S. application Ser. No. 856,968 entitled Firearm With Falling Breechblock", and filed in the names of Carl T. Colliander and Robert L. Hillberg, and now U.S. Pat. No. 3,621,596. Mounted adjacent the pin 36, in a laterally extending bore in cocking lever 66, is a spring loaded plunger 68 which bears against bevelled surface 50 on the inner or right side of shell extractor 26. The plunger 68 urges inward tilting motion of the extractor toward the cartridge such that the projection 42a is firmly received within the groove 22a. Also from FIG. 8, it will be observed that the juxtaposed shell extractor 26 and cocking lever 66 are continguous when the shell extractor 26 occupies its first position. This is due to the plunger 68 urging vertical surface 46 into engagement with the right lateral side 66a of the cocking lever 66. As the shell extractor 26 approaches its second position during rearward pivoting movement, contact between the abutment 60 and the surface 58 will produce an outward tilting of the shell extractor 26 away from the rim of the cartridge 22 or to the left, as viewed in FIG. 8, against the bias exerted thereupon by the plunger 68, the amount of tilt imparted to the shell extractor 26 being determined by the position of Allen screw 62 relative to the receiver 16.

Referring to FIG. 9, it can be seen that the cocking lever 66 comprises a nose 66b which is engaged by a roller 70 mounted on the end of a spring loaded plunger 72 which is axially movable within a longitudinal bore 74 in the receiver 16. This insures that the cocking lever 66 will be maintained in the respective retracted and extended positions when the breechblock is in its battery and retracted positions. It will be appreciated that biasing the lever 66 to the extracted position, wherein the breechblock 12 is correspondingly biased to its retracted position, facilitates insertion of a new cartridge in chamber 20 since a user of the firearm may release the cocking lever.

FIG. 10, which is a top plan view of the breechblock 12, depicts the geometrical features of the top surface of breechblock 12 which cooperate with the shell extractor 26. With reference to FIG. and FIGS. 1 and 2, the front of the breechblock 12 has a slot 12a receding from the chamber confronting face 12b and having a width sufficient to accommodate the lateral tilting motions of the shell extractor 26 and a depth sufficient to permit pivoting of the extractor from the first position to the second position. The function of the slot 12a is then to merely provide a clearance space for the rearward pivoting and lateral tilting motions of the shell extractor 26. Immediately adjacent the slot 12a is a sloping surface 12b, fashioned at the front of the breechblock 12 to engage the surface 42e on the extractor 26 to urge the shell extractor 26 through the last few degrees of pivoting movement in travel from the second position to the first position as the breechblock 12 is raised from the retracted position of FIG. 2 to the battery position of FIG. 1. Forward pivoting of the shell extractor 26 is urged by the surface 12d of the breechblock 12 until the sloping surfaces 12b and 42e engage each other, whereupon a sliding action is occasioned between these surfaces which causes the projections 42a to snap into the annular groove 22a of the cartridge 22. It will be appreciated that the sloping surface 12b is necessary to prevent binding between the breechblock 12 and the extractor hook 42 as the shell extractor 26 assumes the first position.

It should thus be apparent that because the abutment 60 is adjustable with respect to the receiver 16, wider latitude in tolerancing is permissible in the receiver. OPERATION With reference to 'FIG. 1, after the cartridge 22 has been fired, cocking lever 66 of FIG. 9 may be pivoted to the extended position, thereby lowering the breechblock 12 from the battery position of FIG. 1 to the retracted position of FIG. 2. Slightly before the ledge 15 contacts the breechblock 12 in the battery position, projection 38 will contact surface 54 of the lower leg 32 of extractor 26, thereby applying a considerable rearward force to the cartridge 22 via the cartridge hook 42 to overcome any binding which may be occasioned between the cartridge 22 and the walls of chamber 20. The then loosened and partially extracted cartridge 22 may now be displaced rearwardly by the application of a much lesser force. Subsequently, during the falling of the breechblock 12, the

surface 40a of recess 40 contacts surface 52 of leg 32 to impart a faster. rate of pivoting to extractor 28, thereby to remove the cartridge 22 with rapidity. The angular velocity ,of extractor 26 about-pin 36 should be sufficient such, that during brisk falling movement of the breechblock 12 towards the retracted position, the momentum of the cartridge 22 will be adequate to completely extract the cartridge when the extractor 26 is tilted away from engagement therewith. Immediately prior to the shell extractors assumption of the second position,,abutment 60 will contact "car'n surface 58 of the extractor, thereby tilting the extractor 26 against the bias exerted thereupon by the plunger 68 and causing the hook 42 to disengage fromthe cartridge 22 during further rearward pivoting movement toward the second position. In the second position of the extractor 26, the hook .42 will be spaced from the periphery of the cartridge, thereby permitting untrammeled extraction of the cartridge under the impetus of its own momentum or manual extraction, should the falling of the breechblock be very slow. A new cartridge 22 may now be inserted in chamber 20.

Returning the cocking lever 66 from the extended position to the retracted position thereof effects a raising of the breechblock to its battery position. During the first few degrees of forward pivoting from the second position, the extractor 26 will tilt inwardly under the bias of plunger 68 as the abutment 60 slides upwardly along the cam surface 58. After this initial few degrees of forward pivoting, the abutment 60 will disengage from the cam surface 58, and thereafter remain free of contact with the boundaries qf'cavity 56. It will be noted that when the extractor 26 is laterally tilted between its extreme positions (inwardmost and outwardmost positions), the upper leg 28 of the extractor 26, which is received within slot 12a, is accommodated so that there is no hinderance to this tilting movement. During upward movement of the breechblock 12, the surface 12d engages the surface 42d to urge forward pivoting of the extractor 26 until just before the extractor assumes its first position. Inclined surface 42e will then come into contact with surface 12b on breechblock 12 as contoured surface 42b on the hook 42 of the extractor 26 contacts the rearmost rim of cartridge 22. The contact between the surfaces 12b and 42e then urges last few degrees of forward pivoting of the extractor, while the contact between the contoured surface 42b and the rearmost rim of cartridge 22 urges outward tilting of the extractor 26 against the bias of plunger 68. As the surfaces 42e and 12 b clear one another, the projection 42a of hook 42 will snap into the groove 22a under the urging of plunger 68. Upward movement of the breechblock 12 is then continued until the battery position is assumed. The sliding motion between the slanted surfaces 12b and 42e, occasioned just before the projection 42a snaps into the annular groove on the cartridge 22, assures that the extractor 26 will not bind upon the breechblock during the latter portion of its pivoting movement into the first position.

Obviously the invention may be practiced otherwise than is specifically described, without departing from the scope and spirit of the invention, as defined in the appended claims.

What I claim is:

1. In an improved firearm of the type having a receiver with a passage therein, a barrel, having a chamber therein for receiving a cartridge, mounted in the firearm such that the chamber communicates with the passage, a breechblock mounted in the passage for upward and downward movement between battery and retracted positions, a cartridge extractor pivotally mounted in the receiver for movement between a first position and a second position, the extractor being adapted to engage a rim of the cartridge in the first position and to pivot to the second position as the breechblock moves downwardly from the battery position to the retracted position such that the cartridge is at least partially withdrawn from the chamber, and wherein the improvement comprises:

a pivot structure disposed in the receiver for loosely mounting the extractor for pivoting movement between the first position and the second position and for lateral tilting motion;

means urging tilting motion of the extractor toward the cartridge to cause the extractor to firmly engage the cartridge such that movement of the extractor from the first position to the second position withdraws the cartridge from the chamber; and

cam means to tilt the extractor away from engagement with the cartridge during pivoting movement of the extractor from the first position to the second position so as to permit complete withdrawal of the cartridge from the chamber and subsequent insertion of a new cartridge when the extractor is in the second position; and means to adjust the cam means to vary the tilt of the extractor in the second position to thereby allow for wider latitude in tolerances. 2. The combination of claim 1, wherein the cam means comprises:

an abutment mounted in the receiver adjacent the extractor; and a cam surface upon the extractor adapted to be contacted by the abutment during pivoting movement of the lever from the first position to the second position. 3. The combination of claim 2, wherein the adjusting means comprises:

a plurality of threads on the abutment in threaded engagement with the receiver; and means to receive a tool for rotating the abutment. 4. The combination of claim 1, wherein the firearm is of the type having a cocking lever mounted in the receiver for moving the breechblock between the battery and retracted positions and wherein the tilting motion urging means comprises:

a spring loaded plunger mounted in the lever in engagement with the extractor, the lever being mounted upon the pivot structure adjacent the extl'flCtOl'.

Claims

1. In an improved firearm of the type having a receiver with a passage therein, a barrel, having a chamber therein for receiving a cartridge, mounted in the firearm such that the chamber communicates with the passage, a breechblock mounted in the passage for upward and downward movement between battery and retracted positions, a cartridge extractor pivotally mounted in the receiver for movement between a first position and a second position, the extractor being adapted to engage a rim of the cartridge in the first position and to pivot to the second position as the breechblock moves downwardly from the battery position to the retracted position such that the cartridge is at least partially withdrawn from the chamber, and wherein the improvement comprises: a pivot structure disposed in the receiver for loosely mounting the extractor for pivoting movement between the first position and the second position and for lateral tilting motion; means urging tilting motion of the extractor toward the cartridge to cause the extractor to firmly engage the cartridge such that movement of the extractor from the first position to the second position withdraws the cartridge from the chamber; and cam means to tilt the extractor away from engagement with the cartridge during pivoting movement of the extractor from the first position to the second position so as to permit complete withdrawal of the cartridge from the chamber and subsequent insertion of a new cartridge when the extractor iS in the second position; and means to adjust the cam means to vary the tilt of the extractor in the second position to thereby allow for wider latitude in tolerances.

2. The combination of claim 1, wherein the cam means comprises: an abutment mounted in the receiver adjacent the extractor; and a cam surface upon the extractor adapted to be contacted by the abutment during pivoting movement of the lever from the first position to the second position.

3. The combination of claim 2, wherein the adjusting means comprises: a plurality of threads on the abutment in threaded engagement with the receiver; and means to receive a tool for rotating the abutment.

4. The combination of claim 1, wherein the firearm is of the type having a cocking lever mounted in the receiver for moving the breechblock between the battery and retracted positions and wherein the tilting motion urging means comprises: a spring loaded plunger mounted in the lever in engagement with the extractor, the lever being mounted upon the pivot structure adjacent the extractor.