US2301248A - Breech-bolt checking construction for automatic firearms - Google Patents

Description

NOV. 10, 1942. J BROWNING 2,301,248

BREECHBOLT CHECKING CONSTRUCTION FOR AUTOMATIC FIREARMS Filed March 21, 1939 2 Sheets-Sheet l 1942. J. E. BROWNING BREECHBOLT CHECKING CONSTRUCTION FOR AUTOMATIC FIREARMS Filed March 21, 1959 2 Sheets-Sheet 2 Patented Nov. 10, 1942 BREECH-BOLT CHECKING CONSTRUCTION FOR AUTOMATIC FEREARMS Jonathan E. Browning, Ogden, Utah, assignor to Western Cartridge Company,

New Haven,

2 Claims.

This invention relates to improvements in automatic firearms and relates more particularly to a construction and arrangement of parts whereby the breech-bolt and associated parts (commonly referred to as the firearm-action) have their rearward travel (occasioned by the discharge of the firearm) checked or stopped in an improved manner.

One of the objects of the present invention is to provide an automatic firearm with a superior construction and arrangement of parts whereby the rearward travel of the breech-bolt and associated parts is checked or stopped without undue strain and wear upon the parts.

A further object of the present invention is to provide an automatic firearm with superior means whereby the rearward travel of the breechbolt and associated parts is effectively checked without occasioning the rapid rebound thereof.

Another object of the present invention is to provide a superior and reliable automatic firearm-construction wherein the rearward travel of the breech-bolt and associated parts, following the discharge of the firearm, is effectively but gradually checked or stopped preparatory to the return movement of the said breech-bolt and its associated parts to their normal positions.

A still further object of the present invention is to provide a superior automatic firearm-construction wherein the return movement of the breech-bolt and associated parts to their normal positions, after having been operated by the discharge of the firearm, is sufiiciently delayed or retarded to permit the complete ejection of the just-fired shell and the proper positioning of a fresh cartridge preparatory to the automatic 1nsertion of such fresh cartridge into the cartridgechamber of the firearm.

With the above and other objects in View, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1a is a broken view partly in side elevation and partly in vertical, central, longitudinal section of the rear portion of an automatic firearm embodying the present invention;

Fig. 1b is a similar view of the forward portion of the firearm;

Fig. 2 is a view corresponding to Fig. la. but

when the firearm-action is in its rearmost position immediately following the discharge of the firearm;

Fig. 3 is a fragmentary view in vertical, central, longitudinal section of the portion of the firearm immediately adjacent the junction of the buttstock-portion and the rear portion of the receiver, and showing the parts in the positions in which they are shown on a smaller scale in Fig. 2;

Fig. 4 is a transverse sectional view taken on the line l-S of Fig. 3;

Fig. 5 is a broken view in side elevation of the rear portion of the receiver and the forward portion of the receiver-extension;

Fig. 6 is a transverse sectional view taken on the line E-S of Fig. 5;

Fig. 7 is a broken view in side elevation of the rear portion of the action-slide; and

Fig. 8 is a rear elevation thereof.

The particular automatic firearm herein chosen for the purpose of illustrating the present invention is of the gas-operated type, in which the gas pressure developed by the firing of a cartridge is utilized to efiect the rearward travel of the breech-bolt, accompanied by the extraction and ejection of the just-fired cartridge preparatory to the return movement of the said breech-bolt to effect the reloading of the firearm with a fresh cartridge in readiness for again discharging the firearm.

The automatic firearm shown in the accompanying drawings includes a receiver l0 rigidly secured at its forward end to the adjacent rear portion of a barrel H, which latter is provided with the usual axial bore l2 through which the bullets are forwardly propelled in the usual manher of firearms. Attached to the receiver l0 and the barrel Ii is a stock I3 preferably formed of Wood or other heat-insulating and shock-absorbing material.

The stock [3, just above referred to, includes a buttstock-portion l4 and a forestock-portion l5, both of which are integrally united with each other, though, if desired, a separate buttstock and a separate forestock may be employed, in accordance with common practice in firearm constructions.

The receiver 19 is provided in its interior with a longitudinal bolt-receiving chamber IS in which is adapted to reciprocate, in any approved manner, a breech-bolt ll, not requiring detailed description herein. The bolt-receiving chamber IB, just referred to, is flanked on each of its respecshowing the positions which the parts assume tive opposite sides by side walls l8--|8 depending from a top wall it of the receiver it and skeletonized at their rear portions by apertures 20 to reduce the over-all weight of the said receiver. As will be seen by reference to Figs. 1a and 2, the top wall iii of the receiver iii is cut away at its forward portion to accommodate the upper portion of the breech-bolt i? when the same is in its closed position, and to provide a locking-abutment 2! which faces forwardly and which is adapted to be engaged by a rearwardly facing locking-abutment 22 formed upon the upper rear portion of the breech-bolt ii.

The extreme rear portion of the receiver ii] is formed integrally with a depending L-shap'ed arm generally designated by the reference character 23 and comprising a substantially-vertical reach as and a substantially-horizontal forwardly-extending reach 25.

The substantially-vertical reach 2 3 of the L- shaped arm 23 at the rear end of the receiver It is provided with a threaded bore 26 receiving the externally threaded forward end of a tubular receiver-extension 27 having at its rear end a relatively-thick end-wall 26. The said end-wall is provided with an axial threaded passage receiving' the adjacent threaded end of a screw 28 extending forwardly at a slightly upwardly-inclined angle through a similarly inclined passage 52% formed in the buttstock-portion It. The extreme rear or head-end of the screw 28 is seated in a suitable recess in a buttplate 3i mounted against the butt-end of the buttstock-portion M as indicated in Figs. 1a and 2-.

The tubular receiver-extension 1 is accommodated in a bore '32 formed in the buttstockto, constitutes a rigid extension of a cross-head 7 36 forming the rear part of an action-slide generally designated by the reference character 31?, and

including also two. parallel laterally-spaced-apart side-bars 3$ii extending in substantial parallelis'm with the axis of the receiver-extension 27,.

Each of thesaid side-bars is adapted to reciprocate, in a manner as will hereinafter appear, against the lower edge 3% of the adjacent one of the two side-walls I3i8 of the receiver It, and against an upwardly-facing supporting-ledge 49 forming a feature of the adjacent side-arm ti, one of which latter depends from each of the sidewalls l-'Sl3 of the receiver I'll.

At their forward ends, each of the side-bars 3833 of the action-slide 3? are pivotally connected by means of a screw 42 to the rear end of an actuating-rod 53. The said actuating-rod 43 reciprocates beneath the barrel H and extends through a clearance-passage 44 formed in a barrel-lug t integrally formed with and depending from the barrel I l. Immediately below the lower end of the barrel-lug 65, the forestock-portion I5 is provided in its under face with an escutcheon 4'6 through which upwardly projects an attaching-screw l'i extending into threaded engagement with the barrel-lug d5. The'lower portion of the barrel-lug 55 fits into an upwardly-opening socket 3 intersecting at its upper end a longitudinal recess 49 formed in the upper face of the forestock-portion I5 and accommodating, in addition to a portion of the barrel II, the forward portion of the action-slide 31 and the rear portion of the actuating-rod 43, as is clearly indicated in Fig. 1b.

The forward end of the actuating-rod 33 is integrally formed or otherwise attached to a tubular-piston 50 which encircles the barrel H and which is adapted to reciprocate thereon in a manner as will more fully hereinafter appear. The forward edge of the tubular-piston 50 is 3 formed with a notch 5i which is normally in registration with the outer end of a gas-port 52 extending radially through the barrel H from its bore I2 to its outer periphery, to provide for the conduction of gas-under-pressure to the forward end of the tubular-piston til.

Surrounding the exterior of the tubular-piston 58 when the same is in its forward'position, is the rearwardly-extending skirt 53 of a cylinder 5%. Said cylinder 54 is formed with an internally-threaded forward-portion 55 threaded onto a threaded-portion 56 of the barrel I I. so as to be adjustable longitudinally with respect to the said barrel for the purpose of covering or uncovering more or less of the outer end of the gas-port 52.

The skirt 53 constituting the rear portion of the cylinder 5 has its inner surface spaced from the adjacent exterior surface of the barrel H to a degree sufiicient to accommodate, with a free sliding fit, the tubular-piston 59 before referred to. In conjunction with the adjacent surface of the barrel ii, the inner surface of the skirt 53 provides a tubular gas-chamber 5? in which. the tubular-piston 5B is normally located.

For the purpose of enabling the action-slide 31 and its associated parts to be manually moved rearwardly in lieu of its automatic movement, the right-hand one of the. two side-bars 38-38 of the said action-slide has pivotally connected to it by means of a stud 58,, the lower end of a substantially-vertical arm 5'9 of an L-shaped link 40. The said L-shaped link Gil also includes a relatively-long substantially-horizontal arm 6| reciprocating in a guide-way 6.2 formed in the adjacent side-wall of the receiver Ill and is provided at its rear end with a knob or operating handle 6.3 as is indicated in Figs. la and 2. Pivotally attached to the rear cross-head. 3,6 of the actionslide El by means, of a pivot-pin H is the lower end of a breech-bolt-operatinglink 64 which, in turn, has, its upper end pivotal-1y connected by means of a pivot-pin 18 to the lower rear por-.

tion of the breech-bolt I! which latter is mounted for tiltingv and reciprocating movement in the bolt-receiving chamber 16 in the receiver It as is indicated in Figs. 1a and 2.

Considering now the primary means whereby the rearward movement of the firearm-action is checked, it will be noted by reference to Figs. 3 to 5 inclusive in particular, that the upper surface of the, horizontal. reach 25 of the L-shaped arm 23 of the receiver it is formed with a checking-surface t5 which is inclined forwardly and downwardly with respect to the complemental checking-surface 66 formed by the particular portion of the under face of the receiver H3 which is located just forward-ly'of the junction of the L-shaped arm 23 with the receiver i=0 proper, as is indicated particularly well in Fig. 5.. The angular relationship between the checking- surfaces 65 and 66, just referred to, may vary under dif- 'fere'nt conditions, but in the particular instance illustrated, approximately a seven degree departure from parallelism has been found to be satisfactory.

By reference to Figs. 7 and 8, in particular, it will be observed that the upper surface of the cross-head 36 and the adjacent upper surfaces of the side-bars 33-38 of the action-slide 3'! constitute a checking-surface El engageable with the checking-surface 66 of the receiver it, while the under face of the said cross-head 3t constitutes a checking-surface 6B engageable With the checking-surface (55 of the horizontal reach 25 of the L-shaped arm 23. The engagement of the respective checking-surfaces just referred to, is clearly shown in Figs. 2, 3 and 4.

As will be seen by reference to Figs. 1a, 2 and 3 in particular, the under face of the L-shaped arm 23 of the receiver I is provided with a transverse locating-groove 69 which receives a locating-rib i8 upstanding from the rear portion of a trigger-plate l i. The said rear portion of the trigger-plate H is secured to the receiver It by means of an attaching-screw 12 extending upwardly through the trigger-plate H and into a threaded bore 13 (Fig. 3) in the horizontal reach 25 of the L-shaped arm 23.

About midway of its length the trigger-plate H is formed with an integral loop-like triggerguard W in which is located a trigger 15 by means of which latter the firearm may be discharged in any suitable manner, such, for instance, as is shown and described in my copending application Ser. No. 136,523, filed April 13, 1937.

The forward end of the trigger-plate H is formed with an attaching-finger l6 which is secured in any suitable manner to the adjacent portion of the receiver if! and which overlies the adjacent portion of the bottom wall of the forestock-portion i5, as shown in Figs. la and 2.

In order to make clear the operation of the automatic firearm above described and illustrated in the accompanying drawings, let it be assumed that the firearm is loaded preparatory to being fired and that the tubular-piston 56 and the connected parts are in their forward positions as indicated in Figs. 1a and It).

With the parts in the position just above referred to, when the trigger I is pulled the firearm will be discharged with the result that the projectile or bullet will be propelled forwardly through the bore I2 of the barrel II and gasunder-pressure will pass radially outwardly from the said bore i2 through the gas-port 52 into the forward end of the gas-chamber 51 with the result that the tubular-piston 5?] will receive a rearward kick so to speak.

The rearward movement of the tubular-piston 50 will correspondingly move the actuating-rod 43, action-slide Si, spring-guiding plunger 35 and the associated parts. The rearward movement of the action-slide 37 will compress the breechclosing spring 3-3 in the tubular receiver-extension 21 and will, through the intermediary of the link 64, first rock the rear end of the breechbolt l1 downwardly to disengage its lockingabutment 22 from the locking-abutment 2| of the receiver 19, following which the said breechbolt will be moved bodily rearwardly in the boltreceiving chamber [6 of the said receiver l0 and will effect the extraction and ejection of the justfired cartridge.

As the action-slide 3i nears the completion of its rearward movement, the checking-surfaces 61 and 63 at its rear end will be brought into wedging engagement with the complemental checking- surfaces 65 and 66 at the rear end of the receiver I0 as is shown in Figs. 2 and 3. The engagement of the checking-surfaces as just described will serve to check the rapid rearward movement of the action-slide and its associated parts without occasioning deformation of the parts and without causing a rapid rebound such as might so rapidly close the breech-bolt H as to cause the same to jam against a fresh cartridge while the same is enroute into the cartridge-chamber of the barrel H.

Owing to its resilient character, the horizontal reach 25 of the L-shaped arm 23 of the receiver is will yield sufficiently as the checking-surfaces above referred to come into engagementin the manner described to further assist in relatively gradually checking the rearward movement of the action-slide 31 and its connected parts, and in avoiding an objectionable rebound of the firearm-action.

After having been moved rearwardly as above described, the action-slide 3? and its connected parts, including the breech-bolt i1, will be moved forwardly under the urge of the breech-closing spring 33 to effect the insertion of a fresh cartridg into the cartridge-chamber of the firearm and the closing and locking of the breech-bolt l1, preparatory to again discharging the firearm. The parts will now have again assumed the positions in which they are shown in Figs. 1a and 1b.

By so constructing and arranging the parts that the rearward movement of the breech-bolt and its associated parts is checked without undue shock, not only are the parts spared the almost inevitable deformation and excessive wear, but one of the major problems connected with automatic firearms is effectively solved inasmuch as the rebound of the breech-bolt and its associated parts is so minimized or obviated as to avoid the danger of the breech-bolt closing so rapidly as to impinge against a fresh cartridge while the same is enroute into the cartridgechamber of the barrel H or its equivalent.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. An automatic firearm including in combination: a receiver formed at its rear end with a depending L-shaped arm extending below the under face of the receiver proper and comprising a substantially-vertical reach and a substantially-horizontal reach integral with and extending forwardly from the lower end of the said substantially-vertical reach in spaced relationship below the under face of the receiver proper, the upper face of the said substantially-horizontal reach being sloped forwardly and downwardly from the said substantially-vertical reach and facing upwardly toward the under face of the receiver proper, the upper face of the said substantially-horizontal reach and the under face of the receiver proper together defining a forwardly-expanding wedge-shaped recess; a breech-bolt reciprocating in the said receiver; an action-slide operatively connected to the said breech-bolt and formed at its rear with a wedgethe L-shaped arm of the said receiver and having an upper face extending substantially parallel and engaging with the under face of the said receiver when the action-slide is retired rearwardly, the said action-slide also having an under face extending substantially parallel and engaging with the sloping upper face of the said substantially-horizontal reach of the L-shaped arm of the said receiver when the action-slide is retired rearwardly; and spring-means urging the said action-slide forwardly away from the L-shaped arm of the said receiver.

2. An automattic firearm including in combination: a receiver formed at its rear end with a depending L-shaped arm extending below the under face of the receiver proper and comprising a substantially-vertical reach formed intermediate its upper and lower ends with a passage leading substantially horizontally from the front to the rear thereof, the said L-shaped arm also including a substantially-horizontal reach integral with and extending forwardly from the lower end of the said substantially-vertical reach in a plane below the said passage, the upper face of the said substantially-horizontal reach being sloped forwardly and downwardly from the said substantially-vertical reach and facing upwardly upper face of the said substantially-horizontal shaped portion normally spaced forwardly from reach and the under face of the receiver proper together defining a forwardly-expanding Wedgeshaped recess; a breech-bolt reciprocating in the said receiver; an action-slide operatively connected to the said breech-bolt and formed'at its rear with a wedge-shaped portion normally spaced forwardly from the L-shaped arm of the said receiver and having an upper face extending substantially parallel and engaging with the under face of the said receiver when the actionslide is retired rearwardly, the said action-slide also having an under face extending substantially parallel and engaging with the sloping upper face of the said substantially-horizontal reach of the L-shaped arm of the said receiver when the action-slide is retired rearwardly; a spring-guiding plunger extending rearwardly from the said action-slide in a plane intermediate the under face of the receiver proper and the sloping upper face of the substantially-horizontal reach of the L-shaped arm at the rear of the said receiver; and a helical breech-closing spring extending through the passag in the substantially-vertical reach of the L-shaped arm of the said receiver and over the spring-guiding plunger of the said action-slide and yieldingly urging the said action-slide forwardly away from the L-shaped arm at the rear end of the said receiver.

JONATHAN E. BROWNING.

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