US3538811A

US3538811A - Double acting bolt-slide coupling buffer

Info

Publication number: US3538811A
Application number: US769984A
Authority: US
Inventors: David A Poole; Frederick P Reed
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1968-10-23
Filing date: 1968-10-23
Publication date: 1970-11-10
Anticipated expiration: 1987-11-10

Description

ite States Patent lnventors Appl. No.

Filed Patented Assignee David A. Poole Groton, Connecticut;

Frederick P. Reed, Davenport, Iowa 769,984

Oct. 23, 1968 Nov. 10, 1970 the United States of America as represented by the Secretary of the Army DOUBLE ACTING BOLT-SLIDE COUPLING BUFFER 9 Claims, 7 Drawing Figs.

U.S. Cl 89/198, 89/169, 89/191 Int. Cl F4ld 5/04, F4 l d l l/ l 2 Field of Search 89/ 1 69,

[56] References Cited UNITED STATES PATENTS 2,965,001 12/1960 Bobco et a1 89/198X Primary Examiner-Samuel Feinberg Assistant Examiner-Stephen C. Bently Attorneys--Edward J. Kelly, Harry M. Saragovitz, Herbert Berl arid Albert E. Arnold, Jr.

ABSTRACT: A firearm bolt actuated for cyclic reciprocation by impact of an energized slide thereagainst is releasably coupled to the slide by a coupling with a double-acting buffer which acts to cushion the impact between the slide and bolt by absorbing a part of the energy in the'slide and then restores the stored energy to the coupled bolt-slide assembly for continued operation without repeated impacts between the bolt and slide.

Patented Nov. 10, 19?@ 353mm Sheet 3 of3 INVENTORS IlnviEL A PDD1 5 Frederick EEEEfl M fwww ATTORNEY 1 DOUBLE ACTING BOLT-SLIDE COUPLING BUFFER The invention described herein may be manufactured, used and licensed by or for the Government without the payment to us of any royalty thereon.

This invention relates to those automatic guns wherein a slide is energized for longitudinal reciprocation by cartridge discharge forces and the slide in turn energizes the bolt for recoil and counter-recoil travel to perform its operational functions such as chambering cartridges into the gun barrel and extracting fired cases therefrom. In some such guns, the slide is subjected to high impact forces when energized because of the discharge characteristics of the cartridge propellant and this results in a severe impact of the slide with the bolt that is damaging to the impacting members and also leads to faulty operation including rupture of the fired cartridge cases during extraction thereof by the bolt.

Prior art discloses attempts to reduce the severity of the initial impact between the slide and bolt by increasing the compressive strength of the drive springs acting forwardly against the slide. It has been found, however, that the effectiveness of such an approach is nullified by the resulting increase in the energy remaining in the slide at the end of its forward travel which causes rebound sometimes to the extent of unlocking the bolt. Also, the large amount of energy lost during repeated impacts between the slide and bolt prevents any reduction in the initial force transferred to the slide to alleviate the problem.

It is therefore one object of this invention to provide for such automatic guns a device for coupling the bolt and slide together which cushions and minimizes the impacts therebetween by transferring a portion of the energy in the impacting member to a spring assembly and then restores the greater portion of the stored energy back to the coupled boltslide assembly to be used thereby in the performance of its operational functions.

It is another object of this invention to provide in such a device for coupling the slide and bolt together a pair of jaws that open upon impact of the slide with the bolt and then close under spring pressure to equalize the velocities of the bolt and slide and hold them closely together.

It is a further object of this invention to provide such a coupling device which also acts as a recoil buffer for the boltslide assembly.

Further objects and advantages of the invention will be apparent from the following specification and the accompanying drawings which are for the purpose of illustration only and in which:

FIG. 1 is a fragmentary, partially cross-sectioned view of an automatic gun with the members of the bolt-slide assembly shown in full in their inoperative positions;

FIG. 2 is a view similar to FIG. 1 but shows the relationships of the members of the bolt-slide assembly when the bolt is partially accelerated by contact of the energized slide;

FIG. 3 is a view similar to FIGS. 1 and 2 but shows the relationships of the bolt-slide assembly members when the bolt is accelerated to a velocity greater than that of the slide;

FIG. 4 is a fragmentary view showing the jaws of the coupling closed to hold the bolt and slide together;

FIG. 5 is a view similar to FIGS. l3 but shows the bolt stopped in its recoil position and the slide driven rearwardly by its inertia relative to the bolt;

FIG. 6 is a view taken along line 6-6 of FIG. 1; and

FIG. 7 is a perspective view of the coupling assembly.

Shown in the FIGS. is an automatic gun 12 having a receiver 14 and a barrel l6. Receiver 14 slidingly mounts for longitudinal reciprocation therein a bolt-slide assembly 18 which comprises a slide 20, a bolt 22 and a coupling assembly 24 that releasably and resiliently joins the bolt and slide together. Slide 20 is driven from its forward position in receiver 14 to a recoil position therein in a conventional manner by a discharge gas actuated piston (not shown). A helical compression drive spring 26 is arranged to be energized by slide 20 during recoil travel for returning the slide to its forward position. During its reciprocation slide 20 acts to feed cartridges into receiver 14 as disclosed in U.S. Pat. No. 3,22l,603 to Lochhead for Cartridge Feeding Mechanism for Fixed-Barrel, Slide-Operated Guns.

Bolt 22, which chambers the cartridges in barrel l6 and extracts the fired cases therefrom, is mounted in receiver 14 for free travel therein between a forward battery position and a rearward recoil position. Bolt 22 includes a pair of wing locks 28 for locking the bolt to receiver 14 when in battery position so as to support the rear end of the chambered cartridge at discharge. Locks 28 are rotated between locking and unlocking positions by slide 20 when moving relative to bolt 22 after the bolt is displaced thereby to battery position, as taught by U.S. Pat. No. 3,242,816 to Reed for Accelerator Mechanism.

Coupling assembly 24 is mounted within a well 30 that extends forwardly into slide 20 from the rear end thereof to bottom 31. Coupling assembly 24 comprises a shaft 32 on which there is slidingly mounted a sleeve 34, and the sleeve is slidingly mounted in turn in a bearing 36 which is threaded into well 30. Adjustably mounted on the front end of sleeve 34 by thread means 37 is a piston 38 which is slidable in well 30 and which when in contact with the front end of bearing 36 establishes the forward position of sleeve 34 in slide 20 and therefor such thread means provides means for adjusting the longitudinal position of the sleeve relative to the slide. A screw 40 having an end 42 which is without threads extends through slide 20 and bearing 36, as shown in FIG. 3, with the end slidingly received by a longitudinal channel 44 in sleeve 34, whereby the bearing is prevented from backing off respective to the slide during repeated displacements thereof and the sleeve is permitted to move longitudinally but is held against rotation in the hearing. A cap 46 is threadingly mounted at 47 on the front of shaft 32 and arranged to contact bottom 31 whereby the distance from bottom 31 to the rear end of the shaft is threadingly adjustable. The adjustment is fixed by a transverse pin 48 through shaft 32 and cap 46. Located on shaft 32 between cap 46 and piston 38 is a stack of Belleville washers which make up a compressible spring 50. Such spring 50 is compressible both by rearward displacement of cap 46 thereagainst when shaft 32 is displaced rearwardly relative to piston 38 and by forward displacement of the piston by sleeve 34 relative to the cap. Spring 50 is compressed to produce a preload from 10-50 pounds according to the requirements of gun 12, by threadingly adjusting cap 46 on shaft 32.

In'tegrally formed on the rear end of shaft 32 is a head 52 which extends radially upward therefrom through a slot 54 that extends forwardly in sleeve 34 from the rear end thereof. Head 52 is essentially rectangular in configuration and is arranged to overhang shaft 32 on both sides to form a pair of diametrically spaced wing surface 55 which have sliding contact with surfaces 56 formed in sleeve 34 by slot 54 to prevent rotation of the head relative to the sleeve and therefore to slide 20. Head 52 also includes on the front end thereof a planar surface 57 which is disposed normal to the long axis of shaft 32 and a cam surface 58 that inclines downwardly and rearwardly from the top of the head.

An essentially rectangular flange 60 with a rear face 62, which is normal to the long axis of sleeve 34, encircles the sleeve forwardly of slot 54 and such flange and head 52 cooperate in forming a pair of gripping jaws 64 as will be explained hereinafter. Head 52 and flange 60 are arranged to be spaced rearwardly of slide 20 so that the head is receivable by a bore 66 extending rearwardly into bolt 22 from front face 68 thereof and rear face 62 of the flange is contactable therewith.

Bore 66 is intercepted by a vertical slot 70 that slidingly mounts a latch 72. Such latch 72 is biased downwardly by springs 71 to a latching position and is provided with a rear face 73 and an inclined surface 74 that extends downwardly and rearwardly from the front face of the latch for camming cooperation with cam surface 58. Rearward displacement of cam surface 58 against inclined surface 74 elevates latch '72 to an open position and permits passage of head 52 thereby.

When surface 57 on head 52 is displaced rearwardly of latch 72, the latch is free to be actuated to its latching position forwardly of head 52 to couple bolt 22 to slide 20. Latch 72 is also actuatable to its open position by contact of cam surface 76 in the bottom of receiver M with the bottom of the latch. Cam surface 76 is located so as to actuate latch 72 to its open position when bolt 22 is in battery.

Provided on the rear end of receiver 14 is a pad 78 which is contactable by bolt 22 to resiliently stop the recoil travel thereof. The recoil travel of slide 20 is resiliently stopped, as shown in FlG. 5, through the contact of flange 60 with front face 68 of bolt 22 which causes spring 50 to be compressed and absorb the inertia of the slide after the bolt is stopped.

Referring to FIG. 1, it is seen that when gun 12 is inoperative bolt 22 is in its battery position with latch 72 held in open position by cam surface 76 and slide 20, uncoupled from the bolt, is in its forward position. Piston 38 is adjusted on sleeve 34 so that the space between rear face 62 of flange 60 and surface 57 of head 52, which is also the space between jaws 64 when closed, is approximately the same as the distance between jaws 64 when closed, is approximately the same as the distance between front face 68 of the bolt and rear face 73 of latch 72. Consequently, when bolt 22 is coupled by jaws 64 to slide 20 the bolt and slide are held closely together to prevent repeated impacts therebetween and consequential loss of energy. The preload given to spring 50 determines the force which holds jaws 64 closed.

When gun 12 is fired and slide 20 is energized by discharge gases through a piston (not shown), the slide is driven rearwardly with head 52 being moved into bore 66 and rear face 62 of flange 60 impacting against front face 68 of bolt 22. immediately, when rear face 62 contacts front face 68 bolt 22 is gradually accelerated rearwardly from zero velocity as shown in FIG. 2, and sleeve 34 is simultaneously driven forward to move piston 38 against spring 50 which is compressed thereby between the piston and cap 46 to absorb a portion of the impact energy in slide and so reduce the degree of impact thereof against the bolt. By this time, slide 20 is coupled to bolt 22 because when surface 57 on head 52 was displaced past latch 72 the latch was immediately spring-biased to its closed position. When the difference between the accelerating forces in bolt 22 and slide 20 is less than the stored energy in spring 50 the spring acts against both cap 46 and piston 38, causing the slide to decelerate and the bolt to accelerate. This results, as shown in FIG. 3, in a recompression of spring 50 through the impact of rear face 73 of latch 72 with head 52 when the velocity of bolt 22 becomes greater than that of slide 20. When the differential velocities of slide 20 and bolt 22 approaches zero due to the reaction of spring 50, as noted above, jaws 64, held closed by such spring as shown in FIG. 4, hold the slide and bolt together and thereby prevent any repeated impacts therebetween and consequential loss of energy during the remaining recoil travel. Thus, almost the entire energy transferred to slide 20 is constructively used by first having part of the energy in the slide absorbed by coupling assembly 24 to reduce the destructive force thereof and then applying the stored energy to smoothly accelerate bolt 22 and simultaneously decelerate the slide to the desired velocity for boltslide assembly 18.

When bolt-slide assembly 18 reaches recoil position, bolt 22 is stopped by contact thereof against pad 78 which cushions the impact. The inertia of slide 20 forces sleeve 34 forwardly to compress spring 50 and thereby transfer the energy in the slide thereto. When the velocity of slide 20 reaches zero, the energy transferred to drive spring 26 during recoil travel of the slide and to spring 50 by the impact of bolt 22 against pad 78 accelerate the slide forwardly with the bolt being smooth picked up by contact of head 52 with latch 72 as the impact therebetween is cushioned by spring 50. When bolt 22 approaches battery position, the bottom end of latch 72 rides up cam surface 76 to elevate the latch to its open position. Consequently, when bolt 22 goes into battery, slide 20 is uncouple therefrom and free to continue uninterrupted to its forward position with locks 28, actuated by the relative movement between the bolt and slide, securing the bolt in battery position.

We claim:

1. in a firearm, a slide-bolt assembly comprising a slide energized by cartridge discharge forces for longitudinal reciprocation between a forward position and a recoil position, a bolt slidingly mounted for free reciprocal travel between a forward battery position and a recoil position, and a coupling assembly carried by said slide for releasably and resiliently connecting said slide and bolt together for reciprocal travel, said coupling assembly including a pair of jaws, a spring operationally disposed between said jaws for holding said jaws resiliently closed, means for adjustably preloading said spring to produce the desired tension holding said jaws closed, and spaced surfaces on said bolt respectively contactable by said pair of jaws so as to be gripped therebetween for holding said bolt and slide together.

2. The invention as defined in claim 1 wherein one of said jaws receives pressure from the related one of said spaced surfaces when the velocity of said slide is greater than that of said bolt and said jaws are in gripping relationship therewith, and said coupling assembly includes means for transmitting the pressure applied to said one of said pair of jaws to said spring and applying the transmitted pressure from said spring simultaneously to said slide for reducing the acceleration thereof and to said bolt for increasing the velocity thereof to equalize the velocities of said slide and bolt, and wherein a second one of said pair of jaws receives pressure from the related one of said spaced surfaces when the velocity of said bolt is greater than that of said slide and said jaws are in gripping relationship with said bolt, and said coupling. assembly includes means for transmitting the pressure applied to said second one of said pair of jaws to said spring and applying the transmitted pressure from said spring simultaneously to said bolt for decreasing the acceleration thereof and to said slide for increasing the velocity thereof to equalize the velocities of said bolt and slide.

3. The invention as defined in claim 1 wherein said firearm includes a buffer device contactable by said bolt when adjacent recoil position to reduce the velocity thereof to zero, and one of said spaced surfaces applies pressure to the related one of said pair of jaws when the velocity of said bolt is less than that of said slide for displacement of said related jaw, and including means for transmitting displacement of said related jaw to said spring for gradually reducing the velocity of said slide to zero. V

4. The invention as defined in claim 1 wherein said slide includes a well extending forwardly thereinto to a bottom for mounting said coupling assembly, and said coupling includes a shaft, a sleeve slidingly mounted on said shaft, a bearing threaded into said well for slidingly mounting said sleeve, a piston mounted on a front end of said sleeve for sliding displacement in said well, said piston being contactable with a front end of said bearing to establish the forward position of said sleeve in said slide, and a cap threadingly mounted on a front end of said shaft for contact with the bottom of said well, and wherein said spring is mounted on said shaft between said cap and said piston so as to be compressible both by rearward displacement of said cap thereagainst when said shaft is displaced rearwardly relative to said piston and by forward displacement of said piston by said slide relative to said cap, and said pair of jaws are respectively formed on said shaft and sleeve.

5. The invention as defined in claim 4 wherein said means for preloading said spring includes thread means for mounting said cap on said shaft.

6. The invention as defined in claim 4 wherein one of said pair of jaws is formed as a flange on said shaft and the other one of said pair of jaws is formed as a head extending radially from said shaft, and wherein said flange and said head are spaced rearwardly from said slide for gripping engagement with said spaced surfaces on said bolt.

7. The invention as defined in claim 6 wherein one of said spaced surfaces is a front face of said bolt, and said bolt includes a bore extending rearwardly thereinto from said front face for receiving said head and a latch mounted for sliding displacement into said bore from an unlatched to a latching position, and wherein the other one of said spaced surfaces is a rear face of said latch which when the latch is in latching position has contact with a cooperating surface on said head to block displacement of said head from said bore.

8. The invention as defined in claim 7 wherein said head includes a cam surface contactable with an inclined surface on said latch when said head is moved into said bore for elevating said latch to the unlatched position and permitting passage of said head thereby, and including springs for biasing said latch to the latching position after said head is moved past said latch to position said rear face of said latch for contact with said cooperating surface on said head to block displacement of said head from said bore and to transmit rearward displacement of said bolt relative to said slide to said coupling device for compression of said spring.

9. The invention as defined in claim '7 and including means for adjusting the position of said flange relative to said head so that the space therebetween is approximately the same as that between said front face of said bolt and said rear face of said flange whereby said bolt is firmly gripped by said jaws when engaged therewith.