US2948195A - Breech mechanism for automatic firearms - Google Patents

Description

Aug. 9, 1960 F. UNDER BREECH MEGHANISM Foa AUTOMATIC FIREARMS n MZ., i

Aff/s United States Patent O BREECH MECHANISM Fon AUTOMATIC FmEARMs Friedrich Linder, zdrieh, switzerland, assigner te Md-V chine Tool Works Oerlikon, Administration Company, Zurich-Oerlikon, Switzerland, a company of Switzer-l land Filed Feb. 3, 195s, ser. No. 112,813 Claims priority, application Switzerland Feb. 7, 1957 1 Claim. (cl. s9-1s3) The present invention relates to a breech mechanism for automatic firearms, and has theprimary objects of providing a breech mechanism inV which the inertia mass is divided into two parts, the rear part of which is accelerated at a higher rate than the forward part, resulting in a smaller total inertia mass than in pure breech mass locked breech mechanisms and dispensing with a gas drive therefor, and at the the same time providing a safe abutment for the bottom of the cartridge when fired. It is another important object of the invention to provide -a breech mechanism o f the kind referred to, wherein the locking of the breech is abolished at the moment only, when the projectile has left the barrel and the pressure in the barrel has dropped to a value which It is yet another important object of the invention to provide a breech mechanism of the kind referred to which is suitable also for medium and large caliber automatic weapons. v

With these and other objects in view, I provide a breech mechanism for automatic fire arms, comprising in combination: a barrel, a breech head takingrthe thrust of the bottom of the cartridge fired, a rear breech portion, locking means therefor, said rear portion being slidable longitudinally and-the said locking means being moveable transversely of the axis of the said barrel, and a locking tongue extending axially from the said rear portion towards said breech he'ad and engaging with play said locking means, said breech headbearing through said locking means on roof-like -inclined faces stationary relative said barrel and on inclined faces directed transversely thereof on said rear portion, whereby said breech` head when recoiling accelerates said rearportionjat anl increased rat-io, said locking means after initial transverse movement owing to backsliding of the said breech head, is locked during part of the rearward movement of the said rear portion and thereby in turn interlocks the said breech head rigidly with the said barrel.

A breech mechanism according to the invention is not affected by the inavoidable fluctuations in the pressure rise within the cartridge in the course of time after priming. It is also safeguarded against rebound phenomena occurring in the breech which in known breech mechanisms did not provide with certainity that the components of the breech are at the moment of the shot development at a completely closed position and at rest. This danger may be countered by reboundpreventing means, which however in their known embodiments are only rebound-damping or rebound-delaying devices by which the element of danger set forth hereinabove is only reduced but not completely eliminated.

This uncertainty, which is disquieting to the gunner, was also the reason why one had not yet dared to provide automatic weapons of medium or large caliber with such known breech mechanisms. With ammunition of small caliber weapons delayed burning after priming ocdoes not mean any more danger to the cartridge case.

ice

curs to a far lesser extent than with larger calibers, since the priming charge ignites the comparatively small charge at once and uniformly. However, the larger the charge, themore uneven the ignition thereof and the higher the` danger of burst cartridge cases.

These difficulties have been successfully overcome by the present invention. In order that the same and its various details and features may be clearly understood" and readily carried into effect, two embodiments thereof will now be described by way of example with reference to the accompanying drawings, in which for cl-arity only those components are illustrated, which are essential for the understanding of the invention, and wherein:

lFig. 1 Iis a vertical section of a breech according to the invention.

Fig. 2 is a horizontal section of a first embodiment of the breech locked by means of abutment aps, in the priming position,

Fig. 3 shows the breech according to Fig. 2 in the portion 4 of the breechfforces the breech as a wholeinto the priming position shown in Figs. 1 and 2. On the breech head 2 an extractor l3 is fixed and in the locking tongue 9 of Ithe rear portion 4 of the breech a percussion pin 5 is pivoted by means of a pin 14, said percussion pin reaching through a bore 15 of the breech head 2. The rear portion 4 of the breech transmits the pressure through the face 4d on to the breech head 2, which `in the priming position abuts in turn the faces 10b of the casing 10. Rearwardly the breech head 2 bears through two abutment flaps 8 on inclined faces 10a of the casing 10. These abutment flaps 8 are forced by the inclined faces-4a of the rear portion 4 of the breech into a swung-out position (conf. Fig. 2). A cartridge casing 11 inserted into the barrel 1 bears on the face 2a of the breech head. The scar 7 serves in the usual manner for retaining the breech in the cocked' position in that it abuts the inclined face 4e of the rear the usual manner, whereafter the cartridge casing forces the breech head 2 rearward. This thrust is transmitted by the abutment ilaps 8 to the inclined faces 10a on the casing 10, and since these inclined faces are not selflocking and the faces of the flaps 8 opposite to the faces 4b of the lock-ing tongue 9 do not contact these latter faces but stand at a distance from them, the abutment iiaps 8 will tend to give way inwardly. In this way, in the battery position there is no positive locking of the breech head; the lock-ing action is assumed only by the combined mass of the two breech portions 2 and 4. By the inward movement of the abutment iiaps 8 they impart to the rear portion y4 of the breech through the inclined faces 4a of the latter a rearward acceleration, until the abutment flaps 8 in `an intermediate position come into contact with the two parallel faces 4b of the lock- Patented Aug. 9, 1960 ing tongue 9 of the rear portion 4 of the breech while stillcontacting the faces a (see Fig. 3). During this operation the breech head 2 has moved rearward a short stretch but` is restrainedyfrom further movement by` the abl'itrnent-ilapsV contacting the two parallel faces 4b of the.v

lockingftongue 9. The breech head is .thereby/:positively locked.

The rear portion 4 of the breech continues its movement owing to its inherent kineticY energy,` until the support of the abutment aps by the two parallel faces 4b of the locking tongue 9 at lits forward end is abolished andthe abutment aps 8 under the inuence of the thrust Vof the red cartridge swing further inwardly, wherebyy the positive lock-ing of the breech ,head` is abolished. The breech components then assume the unlocked position of Fig. 4. The rear portion 4 of the breech, bythe abutmentface 4c then carries along also the breech head, the return movement of the rear portion of the breech and of the breech head in unisonbeing eectivelfy assisted by the remainder ofthe gases in the barrel.

During` the recoil of the breech the spent cartridge case is ejected in the usual manner by the ejector 3 from the barrel, and the closure spring is loaded, which after the rear reversal of the breech throws the same again forward, whereby a new cartridge is'supplied from the magazine or belt. After the breech head 2 having abutted the faces 10b of the casing, the locking of the breech is eifected in the reverse sequence ofthe unlockingl thereof. The inclined faces 4f (Fig. 4) of the locking tongue 9 spread the abutment aps 8 out, so that.

the same assume again their original. locking position.

head against the weapon casing may alternatively be elected by locking means of a different kind, such asc for example by the slider blocks 12 shown in Fig. 5. The manner of functioning of these slider blocks corref sponds exactly to that of the abutment flaps 8 of thev Figs. 2 to 4.y

The embodiments illustrated show the breechesl each having two locking means 8 or'12, respectively; Nothing` would be changed in the substance of the invention if only one-such locking means were used. Likewise it: is:

possible to build in more such locking means, for exe ample three or even four ofthem.

Other obvious modifications may occur to a personVV skilled in the art, and I. wishto be understood` that I do'notlimit myself to the particular details and dimensibnsfof the preferred embodiments herein described-andl illustrated.

What I claim as my invention and desire to secure by Letters Patent, is:

A breech mechanism for an automatic firearm, comprising in combination a receiver substantially extending along -a longitudinal axis of said firearm, sa-id receiver comprising a iirst abutment faceinclined to said axis; a two-parti' breechbloclo'. movably. guidedy =in saidA receiver, including a breech headloadedby the rearward thrust ofl adired cartridge` and reciprocable between a battery breech mass-lock position, a recoiled. position. and an intermedia-te positivelockposition,` said breech Ablock furf ther includingV a rear breech portion comprising a second abutment face inclined to said axis and a locking tongue with a forwardrend,said= tongue extending axially from saidfurther abutrnentface toward.- said breech head; .a recoil spring engaging said rear breech` portion to bias said breech blocktowardthessaid battery breech mass lock position; locking means movably arranged in said receiver. and engaging said breech head, said locking means in said battery breech mass lockingposition beingV spaced from4 said'locking'tongue and simultaneouslyiengaging both' said abutment faces, said locking means in said' intermediate positivelockposition further simultaneously engaging said first' named abutment'face and said tongue, saidlocking means upan a rearward movement of said breech head out' of 'said' battery breechmass looking position caused' bytheV thrustof a fired cartridge effectinga sliding movement along said rst abutment face towards saidntermediate, positively locked position, therebyxdiminishing said spacing, and simultaneously etfectinga further slidingv movement along said second abutment facertoimpant a recoiling movement to saidl -rear breech portion, said locking means slidingl during;

said recoilin'g movement' along said tongue up to said forward end` and thereupon becoming disengaged from said tongue, and saidlocking means'uponv reaching said forward end'of said tongue under the influence of the thrust of `a red cartridge becoming disengaged from said first' abutment face thereby to unlock said breech head.

References Cited in theflile lof'this patent UNITED STATES PATENTS OTHER -REFERENCES Grossfuss German application Ser. No. G 11,355 Jil/72h; Iuneil'l, 1,956 (KL. 72h, 203).

Stecke Aug. 10, 1937

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