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Publication numberUS2641163 A
Publication typeGrant
Publication dateJun 9, 1953
Filing dateJan 7, 1942
Priority dateJul 26, 1940
Publication numberUS 2641163 A, US 2641163A, US-A-2641163, US2641163 A, US2641163A
InventorsErwin Hepperle, Hanns Lippert
Original AssigneeOerlikon Buehrle Ag
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Buffer mechanism for automatic firearms with breech mechanism locked by inertia
US 2641163 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

June 9, 1953 H. UPPER-r am.



In Switzerland July 26, 1940 Section 3, Public Law 690, August 8, 1946 Patent expires July 26, 1960 1 Claim.

It is known in automatic fire-arms Idesigned on the principle oi breech-locking by inertia to provide spring buffers for the front and rear reversal of the breech block. The arrangement of these spring buffers encountered some diiiiculties. A construction is already known in which the spring buffer for the rear reversal is lodged in the breech bars. The general tendency, however, with increase in ring rate and of the initial velocity of the projectile is to bring down the weight of the moving masses, and therefore to transfer springs and other organs to the stationary parts. This requirement has already been taken into consideration in a known constructional example in which the spring buiers are lodged in the stationary parts, namely, in a cross-head tted in the breech casing. In this arrangement the same springs can he used both for the front and rear reversal.

A drawback of this known arrangement resides in the fact that a special body must be provided, which is comparatively complicated in design and manufacture, rendering assembly more difficult.

The object of the present invention is an automatic fire-arm designed on the principle of breech-locking by inertia in which the provision of special parts for taking up the buffer springs is no longer necessary.

According to the invention the breech casing of an automatic fire-arm working on the inertia locking principle, in which a system of buiier springs is provided for damping the terminal forward and rearward movements of the breech block, is constituted of two parts screwed together and itself includes the buffer springs. The rear end of the buier springs lies against a sleeve sliding in the breech-casing head and supporting itself against the breech-casing proper. With their front end the buffer springs are supported against a buffer piece slidingly fitted on a screwed-in ring. This buffer piece enters the breech-casing head with several buier rammers through corresponding recesses.

A constructional example of a fire-arm according to the invention is shown on the attached drawing,

Fig. 1 shows the re-arm at the moment of front reversal;

Fig. 2-at the moment of rear reversal of the breech block, and is a longitudinal section taken along a plane which is angularly displaced with reference to Fig. 1;

Fig, 3 is a section through the line A--A of Fig. 1;

Fig. 4--a section through the line B-B of Fie. 1;

Fig. 5-a section through the line C-C of Fig. 1.

The barrel I is inserted in the breech-casing head 3 by means of a bayonet joint 2. The breech-casing head 3 is screwed in to the breechcasing proper ll, and secured against rotation by means of the dovetailed locking bar 5. The springs 6 are lodged in borings in the breechcasing head 3. The sleeve 8 slides in a recess 1 in the breech-casing head 3. Its travel to the rear is limited by the breech-casing 4. The springs 6- are supported against the sleeve 8. A threaded ring 9 is screwed into the breech-casing head and on it glides an annular buffer piece I0 provided with several circumferentially spaced bu'er rammers I I, the stroke of which is limited by the breech-casing head. The breech-casing head 3 is provided on the front end with recesses I2 into which penetrate the correspondingly shaped buffer rammers II of the buffer piece, and bear against the springs 6. The thread on the breech-casing head 3 by means of which the threaded ring 9 is inserted in the breech-casing head 3 is not continuous; it is only provided in the intervals between each two buffer rammers. Several springs 6a are lodged in borings in the breech-casing head which do not go all the way through and are therefore directly supported therein. These springs 6a only serve to damp the forward movement of the breech block.

At the end of its forward run the breech-block strikes the sleeve 8 which slides forward against the action of the springs 6 and 6a, whereby the impact of the breech is dampened. After the round has been red, the breech block recoils. Thereby the recuperation spring I4 which is supported against the threaded ring 9 is compressed by the spring casing I5 rigidly connected to the breech-block. Just before the recoiling parts reach their rear-most position, the spring casing I5 impacts upon the buier piece I0. The latter slides rearwards 1and compresses 'the springs E via the rammers II. This action dampens the rear reversal of the breech-block.

We claim:

In an automatic fire-arm of the type wherein the breech mechanism is locked by inertia and wherein a buffer spring system is provided for damping the terminal forward and reaward. movements of the breech block, the combination, with the breech block, of a breech casing composed of a breech casing head and a breech casing proper threadedly connected together, the casing head having a plurality of circumferentially spaced through bores, a plurality of buier springs housed directly in said bores, said casing head 3 having additional bores between the istf-rnentioned bores and open at the rearward ends and closed at their forward ends, additional buffer springs in said additional bores, a sleeve slidingV in the breech casing,r head and supported against the breech casing proper, the buier springs bearing at their rear ends against said sleeve, a ring threadedly connected with the breech casing head, and a buffer piece siidingly fitted on said ring and provided with a plurality of circumferentially spaced buffer rammers penetrating in the rst-mentioned bores of the breech casing headl the forward ends of the springs in such '4 iirsthmentioned bores bearing against said buffer rammers.


References Cited in the le of this patent FOREIGN PATENTS Number l Country Date 500,922 Great Britain Feb. 17, 1939 512,228 Great Britain Aug, 30, 1939 207,365 Switzerland Feb. 1, 1940 214,927 Switzerland Dec. 1, 1941

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
CH207365A * Title not available
CH214927A * Title not available
GB500922A * Title not available
GB512228A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2800837 *Oct 21, 1952Jul 30, 1957Bofors AbBreech block for a gun
US3026777 *May 2, 1958Mar 27, 1962Wooderson Iii Thomas RAutomatic firing mechanism
US5520019 *May 22, 1992May 28, 1996Olympic Arms, Inc.Gas-operated rifle system
U.S. Classification89/198, 89/194
International ClassificationF41A3/82, F24F3/044, F41A3/00
Cooperative ClassificationF41A3/82, F24F3/044
European ClassificationF41A3/82, F24F3/044