US3677133A

US3677133A - Extractor for primer cartridge cases

Info

Publication number: US3677133A
Application number: US108544A
Authority: US
Inventors: Donald F Bushey
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1971-01-21
Filing date: 1971-01-21
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18

Abstract

In large caliber guns which utilize rimless primer cartridges to ignite a separately loaded propellant charge, the required mating engagement between the extractor and the cannelure in the rimless end of the cartridge case is achieved by dividing the extractor into a pair of juxtaposed levers terminating in arcuate ends forming a U-shaped opening of slightly smaller diameter than the firing chamber but in axial alignment therewith. The levers are pivotally joined at a common point and are provided with a spring therebetween for urging the arcuate ends into the cannelure of the cartridge case following the insertion thereof through the Ushaped opening and into the firing chamber. The opposite ends of the levers are pivoted for movement about an axis normal to the vertical axis of the firing chamber in position to be cammed outwardly thereof to extract the cartridge case therefrom during the opening of the breech.

Description

451 July 18, 1972 [72] Inventor: Donald F. Bmhey, Watervliet, NY.

[73] Assignee: The United States of America as represented by the Secretary of the Army [22] Filed: Jan. 21, 1971 [21] Appl. No.: 108,544

Pnmary Examiner-Benjamin A. Borchelt Assistant ExaminerC. T. Jordan Attorney-Harry M. Saragovitz, Edward J. Kelly, Herbert Bel and Albert E. Arnold, Jr.

[ ABSTRACT In large caliber guns which utilize rimless primer cartridges to ignite a separately loaded propellant charge, the required mat ing engagement between the extractor and the cannelure in the rimless end of the cartridge case is achieved by dividing the extractor into a pair of juxtaposed levers terminating in arcuate ends forming a U-shaped opening of slightly smaller diameter than the firing chamber but in axial alignment therewith. The levers are pivotally joined at a common point and are provided with a spring therebetween for urging the arcuate ends into the cannelure of the cartridge case following the insertion thereof through the U-shaped opening and into the firing chamber. The opposite ends of the levers are pivoted for movement about an axis normal to the vertical axis of the firing chamber in position to be cammed outwardly thereof to extract the cartridge case therefrom during the opening of the breech.

9 Claims, 4 Drawing figures PATENTEU JUU 8 I972 SHEEY 1 BF 2 INVENTOR DunulflEEmah ll/J, X aw i.

ATTORNEYS EXTRACTOR FOR PRIMER CARTRIDGE CASES BACKGROUND OF THE INVENTION This invention relates to large caliber guns in which primer cartridges are employed to ignite the regular propellant charge and is more particularly directed to a pivotal extractor for automatically expelling the primer cases from the firing chamber therefor during the opening of the breech.

In guns which fire ammunition of the type wherein the propellant charge and the projectile are separately loaded, the charge is customarily ignited by the discharge of a blank primer cartridge. The required extraction of the fired cartridge case is generally accomplished by a pivotal member positioned to engage with the underside of an enlarged rim formed at the base end of the case. During the opening of the breech, a suitable cam serves to pivot the extractor to expel the case from its firing chamber. Upon the insertion of a new primer cartridge into the firing chamber in the breechblock, the enlarged rim of the case returns the extractor to its original position ready for the next actuation thereof by the cam.

However, during recent efforts to increase the firing rate of these large caliber guns, it was found necessary to eliminate the enlarged rims at the base ends of the primer cartridges in order to facilitate the use of a magazine from which the cartridges could be fed in a semi-automatic fashion. As a result of this new requirement for rimless" cases, the procedure required to load and extract the cartridges has become unduly complicated. For one thing, it is no longer possible to simply utilize the chambering movement of the cartridge to provide the required engagement between the end of the extractor and the cartridge case prior to the initiation of extraction. Instead, the extractor must be displaced at right angles to the chambering path of the primer cartridges to prevent any interference therewith and must thereafter be returned, upon the completion of chambering, to engage in the annular extractor groove or cannelure surrounding the base of the cartridge. Obviously, such manipulation of the extractor requires a relatively complex mechanism whose operation must be properly timed in relation to the opening and closing of the breech. Furthermore, even if the extractor can be arranged to properly function in this manner, the relatively shallow depth of the cannelure does not afford sufficient contact with the end of such extractor, both in area and in time, to insure the transfer of adequate extraction energy thereto.

Accordingly, it is an object of this invention to provide an im roved pivotal extractor for large caliber guns which utilize rimless" primer cartridges to ignite a separately loaded propellant charge.

Another object of the present invention lies in the provision of an extractor for a gun, as aforesaid, wherein the location of such extractor need not be changed during the chambering of each primer cartridge in order to effect the required engagement between the end of the extractor and the extraction groove or cannelure in the base end of the case. I

It is a further object of this invention to provide an extractor, as aforesaid, wherein the engagement thereof in the cannelure of a chambered rimless primer cartridge is automatically achieved at the conclusion of the chambering of the cartridge.

An additional object of this invention is to provide a relatively simple and rugged extractor, as aforesaid, whose configuration is specifically designed to maximize the extent and duration of the contact thereof with the walls of the cannelure in the cartridge case during the extraction thereof from the firing chamber.

SUMMARY OF THE INVENTION It has been found that the foregoing objects can be readily accomplished by an extractor comprising a holder pivotally mounted at one end thereof at a location adjacent the open end of the firing chamber utilized to receive the primer cartridges which serve to ignite the main propellant charge. The interior of the holder is arranged to pivotally support a pair of extractor levers which are jointly pinned in a juxtaposed fashion. Both extractor levers extend outwardly of the holder to terminate in arcuate ends forming a substantially U-shaped opening therebetween shaped to partially block the open end of the firing chamber for the primer cartridges. The U-shaped configuration of the opening formed by the juxtaposed ends of the extractor levers is normally maintained by the bias of a common spring seated between the opposite ends thereof within the holder.

Thus, as the primer cartridge is inserted into the fin'ng chamber through the U-shaped opening formed by the extractor levers, the tapered walls of the cartridge case act on the extractor levers to compress the spring thereby insuring positive engagement thereof in the cannelure in the base end of the case at the conclusion of the chambering thereof. C onsequently, as the breech is opened, either manually or automatically in response to the firing of the gun, a suitable cam in the stationary breech ring serves to pivot the extractor holder outwardly relative to the surface of the breechblock thereby causing the extractor levers to impart sufficient force to the primer cartridge case to effect the expulsion thereof from its firing chamber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a portion of the breech end of a large caliber gun showing the position of the extractor assembly immediately following the withdrawal of a primer cartridge from the firing chamber thereof;

FIG. 2 is an enlarged plan view of the extractor assembly with the holder portion thereof partially broken away to illustrate the details of the extractor levers;

FIG. 3 is an enlarged perspective view of a portion of the structure of FIG. 1 showing the position of the extractor assembly immediately prior to the extraction of the primer cartridge from the firing chamber therefor; and

FIG. 4 is a vertical section taken along line 4-4 in FIG. 2.

DESCRIPTION OF A PREFERRED EMBODIMENT While the extractor of the present invention can be utilized in any large caliber gun which employs separate primer cartridges to ignite the main propellant charge behind the projectile, it is particularly useful in the extraction of those cartridges 12 wherein the customary enlarged rim at the base end thereof is eliminated in favor of an annular extractor groove or cannelure 14.

As shown in the drawings wherein similar reference characters have been employed to designate corresponding parts throughout, the firing chamber 16 for such primer cartridges 12 is generally located so as to be readily accessible to the operating personnel. For example, in the event the gun is provided with a breechblock 18 which, as best shown in FIG. 1, is transversely slidable in the breech ring 20 utilized to support the rear end of gun tube 22, the firing chamber 16 is preferably vertically located in the top of such breechblock 18 in communication with a circular recess 24 surrounding the upper open end thereof. A substantially rectangular extractor opening 26 is also provided in the top of breechblock 18 in adjacent intersection with recess 24 for receiving an extractor assembly 28.

Assembly 28 consists of a generally rectangular holder 30 having outwardly projecting shoulders 32 at one end thereof and a hole 34 extending through such end to rotatably receive a pin 36. The ends of pin 36 extend beyond hole 34 and are suitably fixed in the sidewalls of opening 26 adjacent the end wall remote from firing chamber 16 to pivotally mount holder 30 at a depth which will permit the top surface thereof to normally lie flush with the top of breechblock l8. Shoulders 32 are each formed with an upwardly sloped cam surface 38 facing toward firing chamber 16 in position to contact a mating surface 39 provided at the back of an actuator 40 fixedly mounted by a suitable screw 42 within a substantially rectangular channel 44 provided in the side of breech ring 20. Ac-

tuator 40 is formed with spaced apart arms 46 extending outwardly from the lower portion thereof and is vertically positioned in channel 44 so that arms 46 will lie within correspondingly shaped grooves 48 provided along the top of breechblock 18 so as to straddle firing chamber 16.

The end of holder 30 facing firing chamber 16 is rectangularly recessed, as indicated at 50, to receive a pair of juxtaposed

extractor levers

52 and 54 pivotally joined by a roll pin 56 vertically press-fitted into suitable openings 57 in the upper and lower walls of recess 50.

Levers

52 and 54 are each formed with a laterally extending arcuate tab 58 concentric with roll pin 56 and vertically disposed in overlapping engagement, as best shown in FIG. 4. In addition, a cylindrical seat 60 is provided in each of the ends of

levers

52 and 54 within holder 30 for receiving the ends of a coil spring 62. The opposite ends of levers S2 and 54 extend outwardly of holder 30 to terminate in a finger 64 of reduced cross-section having a planar surface 66 provided with an arcuate surface 68 along the inner edge thereof. In response to the action of springs 62, fingers 64 are juxtaposed to form a U-shaped curvature arranged to fit into the cannelure 14 ofa fully chambered primer cartridge 12.

Thus, a breechblock 18 is moved outwardly of breech ring to open the breech in response to the firing of the gun, cam surfaces 38 on holder shoulders 32 strike the back face of actuator 40 to ride therebeneath. As a result, holder 30 is pivoted upwardly about the axis of pin 36 to lift primer cartridge 12 out of firing chamber 16 in breechblock 18. Inasmuch as the U-shaped curvature at the outer ends of levers S2 and 54 extends fully into cannelure 14, the engagement therebetween is sufficiently prolonged to overcome any tendency for the fired cartridge case to stick in firing chamber 16. In order to facilitate the disengagement of extractor levers 52 and 54 from cannelure 14, the terminal ends of fingers 64 may be slightly tapered along the upper surfaces thereof, as best indicated at 70 in FIG. 4.

As breechblock 18 completes the outward travel thereof in breech ring 20, the top surfaces of shoulders 32 ride along the underside of actuator arms 46 thereby retaining extractor holder 30 in the pivoted position thereof. However, during the return of breechblock 18 to the locked open breech position required to permit the gun to be reloaded, shoulders 32 move beyond the underside of the extractor arms 46 and free extractor holder 30 to drop back to the unpivoted position thereof. At this point, the center of the U-shaped opening formed by

juxtaposed levers

52 and 54 will be aligned with the vertical axis of firing chamber 16 to permit the chambering of a new primer cartridge 12 therein. However, in the event extractor holder 30 may not have completely returned to a horizontal position in breechblock 18, this will be automatically accomplished by the insertion of cartridge 12 through the U-shaped opening between

extractor levers

52 and 54. As cartridge 12 enters firing chamber 16, the tapered walls of the case cause extractor levers 52 and 54 to spread apart and compress spring 62. Thus, as cartridge 12 reaches the fully chambered position thereof, levers 52 and 54 snap into engagement with cannelure 14 therein and, as best shown in FIG. 3, are ready to effect the required extraction of the case during the subsequent opening of the breech.

It is readily apparent from the foregoing that an extractor consisting of a pair of juxtaposed levers arranged to form a U- shaped opening at the end which engages the cartridge is particularly useful where the latter is of the rimless" type especially if such arrangement will permit the cartridge to be fully chambered without the need for changing the location of the pivotal mounting of the extractor during the opening and closing of the breech.

Although the present invention is explained in accordance with the preferred embodiment shown and described herein, it will also become obvious to persons skilled in the art that other forms thereof, as well as changes in the particular forms described, are possible within the spirit and scope of the present invention. Therefore, it is desired that the present invention shall not be limited except insofar as it is made necessary by the prior art and by the spirit of the appended claims.

I claim:

1. An extractor assembly for withdrawing rimless cartridges from a firing chamber in the breech end ofa large caliber gun, comprising,

a pair of juxtaposed levers mounted for pivotal movement about an axis normal to the vertical axis of the firing chamber and connected for pivotal movement about a common axis parallel to the vertical axis of the firing chamber, said levers terminating in arcuate ends forming a U-shaped opening coextensive with the firing chamber but of smaller diameter,

spring means disposed between said levers adjacent the ends remote from the firing chamber for biasing said arcuatc ends to engage with the rimless end of the cartridge upon the insertion thereof through said U-shaped opening and into the firing chamber, and

cam means in the breech end of the gun for pivoting said levers to withdraw the cartridge from the firing chamber in response to the opening of the breech.

2. The cartridge extractor assembly of claim 1 wherein the rimless end of the cartridge includes an annular extractor groove and wherein the distance across the U-shaped opening is less than the maximum diameter of the cartridge to insure the engagement of the extractor levers in the extractor groove.

3. The cartridge extractor assembly of claim 1 including a holder for pivotally receiving said extractor levers, and

means for pivotally mounting said holder in the gun in the path of said cam means.

4. The cartridge extractor assembly of claim 3 wherein said cam means comprises,

a cam shoulder on each side of said holder, and

an actuator fixedly secured in the gun in position to be contacted by said cam shoulders during the opening of the breech for pivoting said holder while said levers are in engagement with the rimless end of the cartridge.

5. In a large caliber gun having an auxiliary firing chamber in the breech end thereof for a rimless cartridge formed with an annular groove adjacent the rimless end thereof and of the type employed to ignite the main propellant charge in he gun, extraction means responsive to each opening of the gun breech for withdrawing the cartridge from the firing chamber, comprising,

a holder pivotally mounted in the gun in spaced relation to the firing chamber for movement about an axis nonnal to the vertical axis of the firing chamber,

a pair of juxtaposed extractor levers pivotally mounted within said holder for movement about a common axis parallel to the vertical axis of the firing chamber, said levers extending outwardly from said holder to terminate in arcuate ends forming a U-shaped opening therebetween coextensive with the firing chamber but of smaller diameter,

spring means seated between the ends of said levers remote from said U-shaped opening for biasing said arcuate ends into the annular extractor groove of the cartridge at the conclusion of the chambering thereof, and

cam means in the gun operative during the opening of the breech for pivoting said holder to actuate said extractor levers for withdrawing the cartridge from the firing chamber.

6. The cartridge extraction means of claim 5 wherein the pivotal connection between said extractor levers includes opposed arcuate tabs extending outwardly therefrom in overlapping relation, and

a pin rotatably seated in said tabs for passage therethrough into fixed engagement with said holder.

7. The cartridge extraction means of claim 5 wherein said arcuate ends of said extractor levers are of lesser thickness than the portions thereof within said holder to fit between the walls of the annular extractor groove in the rimless end of the cartridge.

a cam shoulder on each side of said holder adjacent said transverse pin therethrough, and an actuator fixed in the gun in position to be contacted by said cam shoulders on said holder during the opening of the breech whereby said extractor levers are operated to lift the cartridge out of the firing chamber thereof.

Claims

1. An extractor assembly for withdrawing rimless cartridges from a firing chamber in the breech end of a large caliber gun, comprising, a pair of juxtaposed levers mounted for pivotal movement about an axis normal to the vertical axis of the firing chamber and connected for pivotal movement about a common axis parallel to the vertical axis of the firing chamber, said levers terminating in arcuate ends forming a U-shaped opening coextensive with the firing chamber but of smaller diameter, spring means disposed between said levers adjacent the ends remote from the firing chamber for biasing said arcuate ends to engage with the rimless end of the cartridge upon the insertion thereof through said U-shaped opening and into the firing chamber, and cam means in the breech end of the gun for pivoting said levers to withdraw the cartridge from the firing chamber in response to the opening of the breech.

3. The cartridge extractor assembly of claim 1 including a holder for pivotally receiving said extractor levers, and means for pivotally mounting said holder in the gun in the path of said cam means.

4. The cartridge extractor assembly of claim 3 wherein said cam means comprises, a cam shoulder on each side of said holder, and an actuator fixedly secured in the gun in position to be contacted by said cam shoulders during the opening of the breech for pivoting said holder while said levers are in engagement with the rimless end of the cartridge.

5. In a large caliber gun having an auxiliary firing chamber in the breech end thereof for a rimless cartridge forMed with an annular groove adjacent the rimless end thereof and of the type employed to ignite the main propellant charge in he gun, extraction means responsive to each opening of the gun breech for withdrawing the cartridge from the firing chamber, comprising, a holder pivotally mounted in the gun in spaced relation to the firing chamber for movement about an axis normal to the vertical axis of the firing chamber, a pair of juxtaposed extractor levers pivotally mounted within said holder for movement about a common axis parallel to the vertical axis of the firing chamber, said levers extending outwardly from said holder to terminate in arcuate ends forming a U-shaped opening therebetween coextensive with the firing chamber but of smaller diameter, spring means seated between the ends of said levers remote from said U-shaped opening for biasing said arcuate ends into the annular extractor groove of the cartridge at the conclusion of the chambering thereof, and cam means in the gun operative during the opening of the breech for pivoting said holder to actuate said extractor levers for withdrawing the cartridge from the firing chamber.

6. The cartridge extraction means of claim 5 wherein the pivotal connection between said extractor levers includes opposed arcuate tabs extending outwardly therefrom in overlapping relation, and a pin rotatably seated in said tabs for passage therethrough into fixed engagement with said holder.

8. The cartridge extraction means of claim 5 wherein said holder is disposed within a mating opening in the gun intersecting the firing chamber therein and is pivotally mounted on a transverse pin extending rotatably through one end thereof into fixed engagement in the sidewalls of said opening.

9. The cartridge extraction means of claim 8 wherein aid cam means for pivoting said holder comprises, a cam shoulder on each side of said holder adjacent said transverse pin therethrough, and an actuator fixed in the gun in position to be contacted by said cam shoulders on said holder during the opening of the breech whereby said extractor levers are operated to lift the cartridge out of the firing chamber thereof.