US3174399A - Firing mechanism for automatic firearms - Google Patents

Description

March 23, 1965 H. BRIEGER FIRING MECHANISM FOR AUTOMATIC FIREARMS Filed Feb. 8, 1962 a e r W W fw H I .m a H H United States Patent 3,174,399 FIRING MECHANISM FOR AUTOMATIC FIREARMS Hans Brieger, Zurich, Switzerland, assignor to Machine Tool Works Oerlikon Administration Company, Zurich- Oerlikon, Switzerland Filed Feb. 8, 1962, Ser. No. 171,874 Claims priority, application Switzerland, Feb. 13, 1961, 1,697/ 61 4 Claims. (Cl. 89-132) The invention relates to a firing mechanism for automatic firearms having a device for the displacement of a scar between a release position, in which a lock catch arranged on it is outside the range of an engaging portion of the breech bolt, and an engaging position, in which the lock catch engages into the path on which said engaging portion runs during the forward movement and the recoil stroke of the breech bolt, and having detent means co-operating with said displacement device for locking said sear in the release position.

With a known firing mechanism proposed for attaining a full area contact of the engaging surfaces the locking device, which is mounted on the support of the weapon, is controlled by a component taking part in the recoil movement of the weapon relative toits support and forming the control device, in such a manner that the release of a lock catch is possible during the period at the end of the return of the weapon into the firing position and at the beginning of its recoil.

Such a construction assumes that the weapon is mounted moveably in such a manner that it advances after each recoil into a well defined starting position. When however the device controlling the recoil and forward move ments of the weapon is laid out for certain reasons in such a manner that the weapon during the firing of a series of shots does not return to the starting position occupied at the beginning of the firing, but is braked at any time already during its advance and thrown back by the action of the following shot, the lengths of the advance paths of the individual shots may differ from one another, as well known. When using the aforesaid known firing mechanism with such a weapon having a floating mounting, it may happen that the locking device cannot be brought at all by the control device out of the release position during the individual intervals between shots.

The present invention has the primary object of obviating this disadvantage. With this and other objects in view, which will become apparent later from this specification and the accompanying drawing, I provide a firing mechanism for automatic fire arms comprising in combination: a stationary breech casing, a support, a breech bolt having an initial position in operation reciprocating under the influence of a return spring longitudinally over said breech casing, a scar having a lock catch pivotally mounted relative to said support, a displacement device operatively connected with said sear and displacing the latter between a release position, wherein said lock catch is kept outside the range of the engaging portion of said reciprocating breech bolt, and a holding position, wherein said lock catch engages into the path of said reciproeating breech bolt, during the recoil and advance thereof, and detent means co-operating with said displacement device in the sense of locking said sear in the release position, said breech bolt during the last part of its recoil stroke and first part of its forward stroke while its engaging portion is behind said sear, locking said displacement device by means of said detent means against displacement, and against displacement of said sear into the holding position.

These and other features of my said invention will be clearly understood from the following description of a 3,174,399 Patented Mar. 23, 1965 "ice preferred embodiment thereof given by way of example with reference to the accompanying drawing diagrammatically illustrating my new firing mechanism in longitudinal section in various functional positions, namely:

FIG. 1 illustrates the initial position.

FIG. 2 the release position, e.g. the firing position with the trigger actuated.

FIG. 3 the transitory position from the release position to the holding position.

Referring first to FIG. 1, a casing 2 containing the firing mechanism is attached on the parts 1 of the breech casing. In the lower portion of the casing 2 the buffer spring 4 with damping elements is arranged for taking the impact when engaging the breech bolt 3. Alternatively self-damping annular disc springs may be provided. One end of this spring abuts the casing 2 and the other end abuts a sleeve 5 which is longitudinally slidable in the casing 2. The sleeve 5 has a cam 5a engaging into a slot 6 of the support 7 and abutting the latter. This support 7 has a groove-shaped recess and is mounted in the casing 2, a locking slide 8 forming part of the displacement device and being guided in the interior of easing 2. The forward portion of said locking slide has two faces 8a and 8b. Two roof-like converging abutment cam faces and 8b are arranged ahead of an aperture 9, intowhich engages one arm 10b of a two-armed trigger 10 pivotally mounted on a pivot 11 fixed to the casing 2. The second arm 10a thereof abuts a face 12 which can be raised and lowered when actuating the trigger mechanism (not shown).

The casing 2 is connected with a spring sleeve 13, in the bore of which a bushing 14 is moveably mounted. The latter is subject to the bias of a spring 15 abutting the end-wall of said sleeve, and bears on the wall 8e of the locking slide 8, applying a pressure on it in the direction towards the wall 2a of the casing 2. The displacement device comprises in addition to the locking slide 8, trigger 10, face 12 and trigger mechanism also the sleeve 13, bushing 14 and spring 15.

Referring now to FIG. 2, a sear 16 is pivotally mounted on a pivot 17 fixed to the side walls of the support 7. As will be seen in this figure, a lock catch 18 having an engaging face 18a is inserted into the sear 16 rotatably about a pivot 19. The pivot of this lock catch 18 and of the sear 16 are so arranged that a force applied substantially perpendicular to the engaging face 18a acts on the sear 16 in the sense of turning the same clockwise, while the same force acts on the lock catch 18 in the sense of turning the latter anticlockwise about the pivot 19, forcing thereby the lock catch 18 against the face 16a of the sear 16 and thus assisting the action of a spring 20. Moreover the sear 16 has a supporting face 16b, a projection 21 with the faces 21a and 21b, as well as a bearing surface upon which the spring 28 from the support 7 passes.

Referring now to FIG. 3, a tumbler 22 is mounted on the support 7 pivotally about a pivot 23, the face 22a of which tumbler 22 is convexly curved towards the path of the breech bolt 3. On the tumbler 22 a detent member 24 is mounted pivotally about the pivot 25, and moreover in a bore of said tumbler a spring 26 is housed, which abuts the spring sleeve 13 and bears on the detent member 24 tending to turn the same to the positions illustrated in all three figures. The mounting of the detent member 24 on the tumbler 22 is chosen in such a manner that said detent member 24 abuts said tumbler after a short movement. Moreover the spring 26 applies a bias to the tumbler 22 turning the same anticlockwise about the pivot 23. It tends to turn the same into a rest position shown in FIGS. 1 and 2, in which its face 22b abuts the wall of the spring sleeve 13. The

3 detent member 24 is provided with a projection having faces 24b and 240.

In the breech bolt 3, whose path of movement lies above the breech casing 2, a groove 27 is cut, the rear boundary of which is formed as an engaging portion by the incline 3a, which leads into a control face 3b parallel to the path of movement of a projection of the breech bolt.

From this construction results the following manner of operation: referring again to FIG. 1, the firing mechanisrn is here illustrated in its initial position. The looking slide 8 abuts with its rear end face 8e the wall 2:: of the casing 2. Under the bias of a return spring 29 the breech bolt bears with its incline 3a on the engaging face 18a of the lock catch 18 and thereby applies a moment to the sear 16, which tends to release the same, but cannot turn it owing to the forward portion of the locking slide 8 lying under the face 16b thereof. When the breech bolt 3 is to be released, this is effected by actuating the trigger mechanism, i.e. the arm 10a of the trigger 16 is raised, by raising the face 12 and by its other arm 16b the locking slide 8 is forced forward (to the left) while simultaneously loading the spring 15. During this forward movement the detent member 24 is raised against the bias of the spring 26 by the cam face 8c of the locking slide 8 abutting its face 240, whereby the detent member 24 is slightly turned clockwise relative to the tumbler 22 which remains unmoved. Thereby the cam faces 8c, 8:! of the locking slide 8 can move forward under and past the detent member 24. Moreover the forward portion of the locking slide 8 acting as a bolster slides away under the face 16b of the sear 16, so that the bolstering thereof is abolished. At the same time the forward face 8b of the locking slide 8 abuts the projection face 21!) of the sear 16, whereby an additional rotational impulse is applied to the latter, which reinforces now its turning into the release position illustrated in FIG. 2 (now made possible by the bolstering thereof being abolished), in which position then the sear 16 is arrested by the locking slide acting on its projection 21. The breech bolt 3 released by the sear 16, lock catch 18 thereof respectively can now move forward, i.e. to the left of FIG. 2. This condition is preserved, as long as the trigger mechanism is being pulled, i.e. in the case of a series of shots.

Referring now again to FIG. 3: when the trigger mechanism is released i.e. the face is lowered in direction of arrow, for the purpose of interrupting the firing, nothing happens at first until the moment at which the projection of the breech bolt 3 the control face 3b thereof respectively no longer overlaps the tumbler 22. Thereby the overlapping is abolished, and by the turning of the trigger 10, which is now made possible, and owing to the bias of the spring 15 the locking slide 8 is driven towards the right. By the cam face 8d of the locking slide 8 abutting the face 24b of the detent member 24 a pressure is applied to said face 24b which is transmitted to the tumbler 22. The latter and detent member 24 can now leave their rest portion and give way. It turns clockwise until it abuts the spring sleeve 13, i.e. until its face 22a protrudes into the path of the breech bolt 3. During this turning of the tumbler 22, the cam faces 8c, 8d move away under the detent member 24. At the same time the locking slide 8 releases the projection 21 of the sear 16, so that the same turns counterclockwise under the bias of the spring 28 upon the bearing surface 16c about the pivot 17 until the face 21a abuts the bottom of the support 7, and the engaging face 13a of the lock catch 18 protrudes into the path of the breech bolt 3. After the passing of the cam faces 80, 8d underneath the detent member 24, the latter returns again into the rest position together with the tumbler 22, under the bias of the spring 26 When the breech bolt 3 is in the position shown in chain-dotted lines in F16, 2, i.e. with its control face 3b above the curved face 22a of the tumbler 22, a return movement of the sear 16 into the fully holding position is impossible; for in spite of the thrust applied by the locking slide 8 to the detent member 24, the tumbler 22 cannot be moved, being held down by the projection of the breech bolt 3. The detent member 24 then remains in its rest position, and the locking slide 8 can release the sear 16 for being turned into the holding position then only, when the advancing breech bolt 3 has slid with its control face 3b past the face 22a of the tumbler 22, and the latter turns upward together with the detent member 24 under the thrust of a locking slide 8.

The tumbler 22 accordingly acts as the control member for the locking slide 8. While being overlapped by the breech bolt 3 it prevents the locking slide 8 from releasing the sear 16 for turning into the holding position already at a moment, when, as in the position of the breech bolt indicated in FIG. 2 in chain-dotted lines, the time is no longer sufficient for turning the engaging face 18a of the lock catch 18 in good time sutficently high into the path of the incline 3a for engaging the same for full area contact, before the passing of the breech bolt 3 advancing again after its rear reversal.

However, when after releasing the trigger mechanism, the lock catch 18 has been returned into the path of the recoiling breech bolt 3 (moving to the right in the figure), the nose is resiliently depressed by said bolt running up its face 18b and is turned clockwise about the pivot 19 and thereby swung out of the path of the breech bolt 3 so that the latter can pass unhampered. After the running-over of the lock catch 18 is terminated, the latter is returned by the spring 20 to the holding position in order to catch the advance movement of the breech bolt 3 after the rear reversal thereof, in the initial position illustrated in FIG. 1, whereby the firing is terminated.

While I have described herein, and illustrated in the accompanying drawing what may be considered a typical and particularly useful embodiment of my said invention I wish it to be understood that I do not limit myself to the particular details and dimensions described and illustrated; for obvious modifications will occur to a person skilled in the art.

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

1. A firing mechanism for automatic firearms comprising in combination a support, a pivot on said support, a breech bolt having a control face reciprocating in operation on said support on a linear path of motion, an inclined surface on said breech bolt adjacent said control face inclined towards said path of motion at an inclination of less than a return spring acting on said breech bolt for the forward motion of said breech bolt, holding means for locking said breech bolt in an initial position, said holding means comprising a sear pivotable on said pivot having a stop face, an auxiliary pivot spaced from said pivot on said sear, a lock catch for said breech bolt pivotable on said auxiliary pivot having an engaging face cooperating with said inclined surface and an engaging face cooperating with said stop face, an auxiliary spring for the adjustment of said lock catch cooperating with said sear and said lock catch, spring means acting on said sear for loading said sear in the direction to breech bolt holding position, means for rotating said sear from said holding position to release position, said last named means comprising a locking slide operable by a trigger mechanism movably guided on said support along a line of displacement, said sear having a projection extending into the range of said line of displacement whereby said sear may be moved by said slide against the effect of said spring means.

2. A firing mechanism as claimed, in claim 1, wherein a breach casing is provided and said support is mounted longitudinally slidable in said breech casing with resilient and damping means abutting said breech casing.

3. A firing mechanism for automatic firearms comprising in combination a support, a breech bolt reciprocating longitudinally relative to said support on a straight path of motion, with a rear reversal and a last portion of said path of motion in front of said rear reversal and a first portion behind said reversal, with an initial position on said path, an incline on said breech bolt sloped towards said path, a control face on said breech bolt adjoining said incline towards the rear, holding means pivotally mounted on said support having an engaging face extending towards said incline, a projection on said holding means, said holding means having a release position in which said engaging face is kept outside the range of said incline and a holding position in which said engaging face extends into said path, said holding means having a bearing surface and a supporting surface, a spring supported on one side on said support and on the other side on said bearing surface, said spring urging a rotation of said holding means to holding position, a locking slide having an operating surface and two cam faces movable to a locking position and an opening position so that upon movement from said locking position into said opening position said projection is moved by said slide thereby rotating said holding means into release position, with said operating surface in the locking position of said locking slide, supporting said holding means at said supporting surface with said cam faces being behind said operating surface, detent means comprising a detent member, a tumbler with a convex face, said convex face cooperating with said control face of said breech bolt, said last portion of said breech bolt path being in front of said rear reversal and said first portion behind said reversal, said tumbler cooperating with said detent member for locking the movement of said cam faces into said locking position of said locking slide and for releasing said cam faces for movement into said opening position of said locking slide.

4. A firing mechanism as claimed in claim 3, wherein the engaging portion of said breech bolt has at least a length sufiicient to keep said detent means depressed in the rest position until during the advance stroke of said breech bolt said incline is in juxtaposition with said engaging face of said holding means.

References Cited in the file of this patent UNITED STATES PATENTS 2,524,258 Hepperle Oct. 3, 1950 2,765,709 Hepperle et al. Oct. 9, 1956 2,905,058 Maillard Sept. 22, 1959 FOREIGN PATENTS 716,924 Germany Feb. 2, 1942 925,158 Germany Mar. 14, 1955

Claims (1)

1. A FIRING MECHANISM FOR AUTOMATIC FIREARMS COMPRISING IN COMBINATION A SUPPORT, A PIVOT ON SAID SUPPORT, A BREECH BOLT HAVING A CONTROL FACE RECIPROCATING IN OPERATION ON SAID SUPPORT ON A LINEAR PATH OF MOTION, AN INCLINED SURFACE ON SAID BREECH BOLT ADJACENT SAID CONTROL FACE INCLINED TOWARDS SAID PATH OF MOTION AT AN INCLINATION OF LESS THAN 90*, A RETURN SPRING ACTING ON SAID BREECH BOLT FOR THE FORWARD MOTION OF SAID BREECH BOLT, HOLDING MEANS FOR LOCKING SAID BREECH BOLT IN AN ANIMAL INITIAL POSITION, SAID HOLDING MEANS COMPRISING A SEAR PIVOTABLE ON SAID PIVOT HAVING A STOP FACE, AN AUXILIARY PIVOT SPACED FROM SAID PIVOT ON SAID REAR, A LOCK CATCH FOR SAID BREECH BOLT PIVOTABLE ON SAID AUXILIARY PIVOT HAVING AN ENGAGING FACE COOPERATING WITH SAID INCLINED SURFACE AND AN ENGAGING FACE COOPERATING WITH SAID STOP FACE, AN AUXILIARY SPRING FOR THE ADJUSTMENT OF SAID LOCK CATCH COOPERATING WITH SAID SEAR AND SAID LOCK CATCH, SPRING MEANS ACTING ON SAID SEAR FOR LOADING SAID SEAR IN THE DIRECTION TO BREECH BOLT HOLDING POSITION, MEANS FOR ROTATING SAID SEAR FROM SAID HOLDING POSITION TO RELEASE POSITION, LAST NAMED MEACH COMPRISING A LOCKING SLIDE OPERABLE BY A TRIGGER MECHANISM MOVABLY GUIDED ON SAID SUPPORT ALONG A LINE OF DISPLACEMENT, SAID SEAR HAVING A PROJECTION EXTENDING INTO THE RANGE OF SAID LINE OF DISPLACEMENT WHEREBY SAID SEAR MAY BE MOVED BY SAID SLIDE AGAINST THE EFFECT OF SAID SPRING MEANS.

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