US3890881A

US3890881A - Automatic firing weapon

Info

Publication number: US3890881A
Application number: US390953A
Authority: US
Inventors: Ernst Hurlemann; Jurg Zellweger
Original assignee: Werkzeugmaschinenfabrik Oerlikon Buhrle AG
Current assignee: Rheinmetall Air Defence AG
Priority date: 1972-08-31
Filing date: 1973-08-23
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24
Also published as: IT993829B; DE2365902B2; FR2198114B1; SE387433B; DE2365902C3; DE2339270B2; CH556011A; NL163017C; JPS4967497A; NL7310925A; NL163017B; DE2365902A1; DE2339270A1; FR2198114A1; JPS5416680B2

Abstract

An automatic firing weapon having a housing and a breech-block portion displaceable within the housing, a safety lever pivotably mounted in the housing, the safety lever in cooperative action with a stop at the breechblock portion preventing recoil motion of the breechblock portion. There is further provided a firemoved component which acts by means of a control surface upon the safety lever for rocking or pivoting the safety lever into a position which releases the breechblock portion after firing of a shot. The firing weapon possesses a weapon barrel which is movable relative to the housing, and the control surface is arranged at the weapon barrel and the safety lever possesses a control cam which slides upon the control surface.

Description

[ June 24, 1975 3,713,363 l/l973 Hurlemann...........................89/185 AUTOMATIC FIRING WEAPON Inventors: Ernst Hurlemann, Zurich; Jurg FOREIGN PATENTS OR APPLICATIONS Zellweger, Neerach, both of Switzerland 65,005 11/1946 Denmark.............................. 89/190 Primary Examiner-Stephen C. Bentley Attorney, Agent, or Firm-Wemer W. Kleeman [73] Assignee: Werkzeugmaschinenfabrik OerIikon-Buhrle AG, Zurich, Switzerland [57] ABSTRACT An automatic firing weapon having a housing and a [22] Filed: Aug. 23, 1973 Appl- N03 390,953 breech-block portion displaceable within the housing,

a safety lever pivotably mounted in the housing, the

Foreign Application Priority Data Aug. 31, 1972 Switzerland.......................

safety lever in cooperative action with a stop at the breechblock portion preventing recoil motion of the 12889/72 breechblock portion. There is further provided a fire- 52 0 9 3 5 7 H/S w oo 8 1 00 41 K F l 5n w ,1. W 3 .m R 1 0/ 3 9 W 8. 8 u "9 m m mh c u r n "a u e u "S a .M U mm II. 2 oo 5 55 ranged at the weapon barrel and the safety lever possesses a control cam which slides upon the control surface.

[56] References Cited UNITED STATES PATENTS 3 230 828 1/1966 Maillard..............l.....l...... 89/33 CA 3,566,744 3/1971 89/172 5 Clams, 7 Drawlng Figures PATENTEIJJUN 24 ms SHEET Fig. 4

AUTOMATIC FIRING WEAPON BACKGROUND OF THE INVENTION The present invention relates to a new and improved construction of an automatic firing weapon of the type incorporating a housing and a breechblock portion which is displaceable in the housing, a safety lever pivotably mounted in the housing, the safety lever in cooperative action with a stop at the breechblock portion preventing recoil motion or movement of the breechblock portion, there also being provided a fire-moved component which acts by means of a control surface upon the safety lever for the purpose of rocking the safety lever into a position which releases the breechblock portion after firing a shot.

Accordingto aknown construction of firing weapon of this type the safety lever is actuated by a gas piston acting upon the breechblock. For this purpose the gas piston is constructed as a plunger with a control surface. Since the breechblock is simultaneously unlocked by the plunger and driven into the hooked position, it is not possible to throttle the removal of the gas in a manner as would be necessary for a protective actuation of the safety lever by the plunger. The hard impacts which act upon the safety lever represent a possible rupture danger for such safety lever and therefore impair the operational reliability of the weapon.

SUMMARY OF THE INVENTION Hence, it is a primary object of the present invention to provide an improved construction of automatic firing weapon which is not associated with the aforementioned drawbacks and limitations of the prior art constructions.

Another and more specific object of the present invention aims at the provision of a new and improved construction of automatic firing weapon in which the actuation of the safety lever occurs at reduced load.

Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the firing weapon possesses a weapon barrel which is movable relative to the aforementioned housing, and the control surface is arranged at the weapon barrel and the safety lever possesses a control cam or projection which slides upon the control surface.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and objects other than those set forth above, will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:

FIG. 1 illustrates an automatic firing weapon, partially in longitudinal sectional view and partially in front view, and portraying the breechblock locked in its firing position;

FIG. 2 is a cross sectional view of the firing weapon depicted in FIG. 1, taken substantially along the line II-II thereof;

FIG. 3 is a view, similar to the showing of FIG. 2, but showing the breechblock in its unlocked position;

FIG. 4 is a cross-sectional view of the firing weapon depicted in FIG. 1, taken substantially along the line IV--IV thereof;

FIG. 5 is a cross-sectional view of the firing weapon depicted in FIG. 4, taken substantially along the line VV thereof;

FIG. 6 is a cross-sectional view of the firing weapon depicted in FIG. 4, taken substantially along the line VI-Vl thereof; and

FIG. 7 is a cross-sectional view of the firing weapon depicted in FIG. 4, taken substantially along the line VII-VII thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Describing now the drawings, a weapon housing generally designated by reference character 1 in FIG. 1 is secured in any suitable and therefore not particularly illustrated manner with the cradle or rocker of a gun mount. A barrel or tube 2 is displaceably mounted in a sleeve-shaped component or part 3 of the housing 1. The barrel or tube 2 is resiliently supported against the gun mount. A sleeve 4 connected with the barrel 2 possesses an inwardly directed flange ring 5 which is spaced from the rear end surface 6 of the barrel 2 and the end surfaces or

end faces

7, 8 of which are disposed perpendicular to the lengthwise extending axis of the barrel 2.

As best seen by referring to FIGS. 2 and 3 from the location of the inner surface of the flange ring 5 there are cut thereat or otherwise suitably machined therein grooves 9 which extend parallel to the axis of the barrel, these grooves 9 being arranged at the same angular spacing from one another and having the same width. Between the grooves 9 there are located projections or cams 10 which are somewhat narrower than the grooves 9. As best seen by referring to FIGS. 1 and 4 a breechblock carrier or support 11 is displaceably mounted at the lower portion 1a of the housing 1, this lower housing portion la having a substantially rectangular hollow cross-sectional configuration. The breechblock carrier 11 is subjected to the pressure of a spring 12 or equivalent device which bears against the rear wall 13 of the housing 1. A housing 14 is connected with this rear wall 13 and contains a buffer or shock absorber 15. The head 16 of the breechblock carrier or support 11 possesses a forwardly open bore 17 which extends coaxially with respect to the barrel 2, and in this bore 17 there is rotatably and displaceably mounted a substantially cylindrical breechblock body 18. This breechblock body 18 possesses and outwardly depending flange ring 19, the external diameter of which is smaller than the spacing of the base of each of the grooves 9 of the sleeve 4 from the axis of the barrel 2. The flange ring 19, as best seen by referring to FIGS. 2 and 3, possesses grooves 20 and projections or earns 21 which are present in the same number and width as the grooves 9 and projections 10 of the flange ring 5 of the sleeve 4.

The breechblock body 18 possesses a continuous bore 22 which is stepped in diameter and arranged coaxially with respect to the barrel axis. A firing pin 23 is secured at the head 16 of the breechblock carrier or support 11 and extends into the bore 22 of the breechblock body 18. The breechblock body 18 possesses a bore 24 which completely penetrates therethrough and the axis of which is directed perpendicular to its length wise axis and intersects therewith. A bolt 25 is arranged in the bore 24 and the firing pin 23 which penetrates therethrough serves as the axis of rotation and the posi tional securing means for the bolt 25. Both ends of the bolt 25 extend into two slots 26 which are milled or otherwise suitably formed at the wall of the breechblock carrier head 16. As best seen by referring to FIG. 1 the rear portion 27 of the slot 26 is parallel to the axis of the breech-block body 18 and the front portion or part 28 is directed at an inclination to such axis. The center points of both front circular ends of the slot 26 are located at a line which intersects the axis of the breechblock housing 18, this line enclosing an angle with a horizontal plane. in

According to the showing of FIG. 1 a sleeve 29 is secured to the barrel 2. This sleeve 29 possesses an outwardly depending flange edge 30 for which the housing portion 3 serves as the guide. Furthermore, the sleeve 29 possesses a downwardly depending projection or extension 31. A plunger 32 which is substantially parallel to the barrel 2 is connected with the projection 31. A nozzle 33 is mounted in the wall of the barrel 2. A gas escape or removal bore 34 of the nozzle 33, and which bore is directed perpendicular to the axis of the barrel 2, merges with a bore 35 which piercingly extends through the porjection 31 and the plunger 32. A cylinder 36 is secured at a wall 37 of the housing 1 and is retained by a carrier or support 38 connected with the housing 1. A piston 39 is arranged in the cylinder 36 and is loaded by the forwardly acting pressure of a spring 40 or the like. A piston rod 41 is movably mounted in any suitable and therefore not particularly illustrated manner at the rear floor or base of the cylinder 36 and extends towards the rear out of the housing wall 37. The plunger 32 is displaceably mounted at the front floor or base of the cylinder 36. A bore 42 which piercingly extends through the wall of the cylinder 36 opens into the piston compartment or chamber 43.

Now according to the showing of FIGS. 1, 4 and 7 the breechblock carrier or support 11 possesses a bifurcated or fork-shaped foot or base portion 44 having a recess or depression 45 which is milled in or otherwise machined from the end face thereof. An entrainment member 46 is disposed parallel to the axis of the weapon and extends through a slot 47 of the breechblock carrier-foot or base portion 44 towards the front. A transversely directed projection 48 of the entrainment member 46 is located in front of the base 49 of the depression or recess 45. The projection 48 is displaceably mounted at a rod 50 which extends parallel to the axis of the weapon and under the pressure of a spring 51 bears against the housing wall 37. The entrainment member 46 is connected with a chain 52. A projection or dog 53 of the entrainment memberprojection 48 extends into a slot 54 which is cut-in at the region of the depression or recess 45 at the right side of the breechblock carrier base 44 as viewed in the direction of firing. The projection or dog 53 possesses a surface 55 which is directed perpendicular to a horizontal plane, this surface 55 enclosing an acute angle with the forwardly directed lengthwise central plane of the weapon. The breechblock carrier base 44 possesses at the same side and offset in elevation a groove 56 which is parallel to the axis of the weapon, the front vertical boundary surface 57 of which likewise encloses an acute angle with the forwardly directed longitudinal central plane of the weapon, as best seen by referring to FIGS. 1 and 6.

Now according to the showing of FIG. 4 there is attached to the right outer side of the housing lower portion 1a a bearing or support piece 58. This bearing or support piece 58 possesses three

recesses

59, 60 and 61, the central planes of which are directed perpendicular to the longitudinal central plane of the weapon. A blindhole bore 62 of the bearing or support piece 58, and which blindhole bore is parallel to such plane, opens into the

recesses

59, 60 and 61. In the section of the bore 62 which is located between the

recesses

59 and 60 there is rotatably mounted a bushing 63 with a notched-toothed or serrated bore. An axle or shaft 64 is arranged in the bore 62 and keyed with the bushing 63. The hub of a control cam 65 constructed as a lever and arranged at the recess 59 is keyed with the shaft or axle 64. The control cam 65 extends through a slot 66 in the housing 1 and into the latter. A projection or cam 67 is provided at the barrel 2, this cam or projection 67 having a cylindrical surface 68 which is concentric therewith. A conical surface 69, the apex or tip of which is located at the axis of the barrel, connects the surface 68 with the surface of the barrel 2, as best seen by referring to FIG. 5.

According to the showing of FIG. 6 a safety lever or catch 70 is mounted at the recess 60 of the bearing or support piece 58 and is in driving connection with the shaft or axle 64. A spring 72 arranged in a bore 71 of the bearing piece 58 loads the safety lever 70, so that such bears with its flat or planar surface 73 against the bearing piece 58. The safety lever 70 extends through a slot 74 at the wall of the housing portion 1a into the path of the breechblock carrier or support 11. This slot 74 is in alignment with the recess 60. According to the showing of FIG. 7 a coupling element or piece 75 is arranged in the recess 61 of the bearing piece 58, the hub 76 of the coupling element 75 extending into the part of the bore 62 which is located between the

recesses

61 and 60 and is in driving connection with the shaft 64. The coupling element 75 possesses a downwardly depending projecting or extension 77 which is equipped with a surface 78 which is radially directed with respect to the bore 62. The recess 61 furthermore contains an unlocking lever 79 which is rotatably mounted at the shaft 64. The hub 80 which protrudes upwardly past the unlocking lever 79 and bears at the hub of the coupling element 75 possesses a surface 81 which is radially directed with respect to the bore 62. The unlocking lever 79 is loaded by a spring 82 which is supported at the bearing piece 58, so that it can be held in bearing contact by means of one surface 83 of its hub against the bearing or support piece 58. The unlocking lever 79 engages through a slot 84 at the housing portion la. A surface 85 at the lever end is parallel to the surface 55 of the entrainment projection or cam 53 and is located at a small spacing behind the same.

Having now had the benefit of the foregoing detailed description of the construction of the automatic firing weapon its mode of operation will now be considered andis as follows:

The breechblock carrier 11, after impact of its head 16 against the sleeve 4, i.e., after penetration of the firing cap of a cartridge 86 located in the cartridge chamber of the barrel 2 by the firing pin 53, assumes the position depicted in FIG. 1. As a result thereof, and as best seen by referring to FIG. 2, the radial symmetry planes of the projections or cams l0 and 21 of the sleeve 4 and the breechblock body 18 conicide. The ends of the bolt 25 are located at the rear portion 27 of the slot 26 of the head 16, and the rear end of the plunger 32 bears against the piston 39. As best seen by referring to FIG. 5, the end of the control cam 65 is lo cated behind the surface 69 of the barrel 2. According to the showing of FIG. 6, the safety lever or catch 70 extends into the groove 56 of the breechblock carrier base 44. The surface 700 of the safety lever 70 is located behind the front boundary 57 of the groove 56 and possesses a spacing therefrom which is smaller than the length of the linear portion 27 of the slot 26 of the breechblock carrier head 16. As best seen by referring to FIG. 7 the surface 78 of the coupling element 75 bears against the surface 81 of the unlocking lever 79.

When the breechblock carrier 11 has strongly recoiled after impinging against the sleeve 4, then its surface 57 impacts against the surface 70a of the safety lever 70 and is caught. During the impact the safety lever 70 is essentially loaded by a pressure force which exerts a closing moment on the safety lever 70 and which moment acts in the counterclockwise direction, as viewed in FIG. 6, so that it further remains in the blocking or locking position. During the recoil of the breechblock carrier 11 only the linear portion 27 of the slot 26 of the breechblock carrier head 18 moves along the ends of the bolt 25, so that the breechblock body 18 is not rotated and remains completely locked with the barrel 2.

The gas pressure which has developed after the firing of the projectile propellent charge located in the cartridge 86, acts via the cartridge sleeve 90 and the breechblock body 18 upon the sleeve 4 of the barrel 2, which therefore is accelerated towards the rear and is displaced into the stationary housing 1. As a result, the conical surface 69 of the barrel 2 moves aganist the control cam 65, whereby the same together with the shaft 64 and the safety lever 70 is rotated in the clockwise direction, as viewed in FIGS. 5 to 7. When the control cam 65 comes into contact with the cylindrical surface 68 of the barrel 2 then the safety lever 70 has completely departed out of the groove 56 of the breechblock carrier base 44. This is the case before the rear end of the piston rod 41, which is pushed towards the rear by the plunger 32 moved together with the barrel 2, arrives at the breechblock carrier base 44. During the movement of the control cam 65 and the safety lever 70 the coupling element 75 is entrainably rocked; however the unlocking lever 79 which is not keyed with the shaft 64 remains in the illustrated position.

When the projectile has passed the gas escape location in the barrel 2 then the gas flows through the bores 34, 35 of the nozzle 33, the projection 31 and the plunger 32 in front of the piston 39, and finally into the cylinder chamber or compartment 43. As a result the piston 39 and the breechblock carrier 11, which up to this point in time have moved with the speed or velocity of the barrel 2, are additionally accelerated. The piston 39 thus moves away from the plunger 32.

After the projectile 87 has departed from the barrel 2 and now there is only still effective at the breechblock body 18 the residual gas pressure via the cartridge sleeve 90 which has remained in such barrel, then the bolt 25 impinges against the front inclined portion 28 of the slot 26. The bolt 25 thus has imparted thereto a rotary drive, so that the breechblock body 18 is rotated about its axis and its projections or cams 21 move along the projections or cams of the sleeve 4. The piston 39 is braked at the end of its stroke, after it has imparted to the breechblock carrier 11 the velocity determined by the cadence of the weapon, whereas the breechblock carrier 11 moves further towards the rear. Since the piston 39 now is located behind the bore 42 the gas still located in the cylinder compartment or chamber 43 flows into the surroundings, whereupon the piston 39 is driven back again by the spring 40 into its starting position according to the showing of FIG. 1.

When the breechblock carrier 11 during its rearward movement has separated from the piston rod 41, then the breechblock body 18 has been rotated to such an extent that the symmetry planes of its projections 21 and the sleeve grooves 9 coincide (FIG. 3) and it is now unlocked from the barrel 2. Since the bolt 25 comes to bear at the front boundary of the slot 26 it is accelerated with the breechblock body 18 to the velocity of the breechblock carrier or support 11 and entrainably moved along thereby. Consequently, the projections 21 of the breechblock body 18 extend through the sleeve grooves 9 and the empty cartridge sleeve is pulled out of the barrel 2. During the common further movement of the breechblock carrier 11 and the breechblock body 18 a suitable coupling device which has not been particularly illustrated in the drawing prevents displacement of these

components

11 and 18 relative to one another.

After the breechblock carrier 11 has transferred its energy to the spring 12 it is again moved towards the front after impacting against the buffer 15 by means of the latter, and the breechblock body 18 introduces a new cartridge 86 into the barrel 2 which, after carrying out the return movement limited by a stop or impact surface 88 of the housing 1, again moves back into its rest position.

At the end of the barrel movement the control cam 65 again assumes the position depicted in FIG. 5, and the safety lever extends into the path of the breechblock support or carrier 11.

At the end of the forward movement of the breechblock body 18 the projections 21 extend through the sleeve grooves 9 and impact against an end surface 89 of the barrel 2. The breechblock carrier 11 again moves further towards the front since it is now again uncoupled from the breechblock body 18, whereby the bolt 25 together with the breechblock body 18 is rotated back in the counterclockwise direction, as viewed in FIG. 3, until the symmetry planes of the

projections

21 and 10 of the breechblock body 18 and the sleeve 4 coincide and thus the breechblock body 18 is again locked with the barrel 2.

The safety lever 70 is rocked out of the path of the breechblock carrier 11 which moves towards the forwardmost position, then is driven under the action of the spring 72 in the counter-clockwise direction (FIG. 6) and moved into the groove 56 of the breechblock carrier base 44.

For the purpose of cocking the

breechblock

11, 18, that is to say, for moving the same into the hooked position, the entrainment member 46 is pulled towards the rear, out of the position depicted in FIG. 1, by a force exerted in any suitable and therefore not particularly illustrated manner upon the chain 52. As a result, there is transmitted by means of the entrainment projection or cam 53 a force to the unlocking lever 79, by means of which the same is pivoted in the clockwise direction about the axle or shaft 64, as viewed in FIG. 7, and moved out of the path of the entrainment projection 53. The coupling element 75 is entrainably rocked by the unlocking lever 79, whereby the shaft 64 is rotated and by means of such the safety lever 70 is brought out of engagement with the groove 56 of the breechblock carrier 1 l. The breechblock carrier 11 therefore can be moved towards the rear by the entrainment member 46 which bears against its base 44. As already previously described the breechblock carrier 11 initially carries out a relative movement with respect to the breechblock body 18, whereby such is unlocked from the barre] 2 and subsequently there conjointly occurs the rearward movement of the breechblock carrier 11 and breechblock body 18.

When the entrainment projection or cam 53 has been positioned behind the head 79a of the unlocking lever 79 then the same is again moved by the spring 82 into the path of the entrainment projection 53. After the

breechblock mechanism

11, 18 has reached the hooked position, then, the unlocking lever 79, by means of the projection 53 of the entrainment member 46 which is returned back into its starting position under the action of the spring 51, is briefly rocked out of the path of the entrainment member, whereupon the lever head 79a again is located behind the surface 55 of the entrainment projection 53.

While there is shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,

What is claimed is:

1. An automatic firing weapon comprising a housing, a weapon barrel movable relative to said housing, a breechblock mechanism including a breechblock displaceably mounted in said housing, a pivotable shaft, a safety lever pivotably mounted in the housing on said pivotable shaft, said breechblock having a stop, the safety lever in cooperative action with the stop at the breechblock preventing recoil movement of the breechblock, a control cam pivotally mounted in said housing on said pivotable shaft, the control cam and said safety lever being connected with said pivotable shaft, an unlocking lever mounted on said pivotable shaft, means for placing said unlocking lever in driving connection with said pivotable shaft and means associated with said breechblock for manually actuating said unlocking lever, said barrel acting by means of a control surface thereon upon the control cam sliding-upon said control surface for displacing the safety lever into a position releasing the breechblock after firing a shot.

2. An automatic firing weapon comprising a housing, a breechblock mechanism including a breechblock component displaceably mounted in said housing, a safety lever pivotably mounted in the housing, said breechblock component having a stop, the safety lever in cooperative action with the stop at the breechblock component preventing recoil movement of the breechblock component, a fire-moved component acting by means of a control surface upon the safety lever for displacing the safety lever into a position releasing the breechblock component after firing a shot, the improvement comprising the firing weapon possessing a weapon barrel defining the fire-moved component and movable relative to said housing, the control surface being arranged at the weapon barrel, the safety lever being provided with a control cam which slides upon the control surface, a common shaft upon which there are seated the control cam and said safety lever, the control cam and safetylever being connected with said common shaft, an unlocking lever, a one-way coupling means for placing into driving connection said unlocking lever with said common shaft, said unlocking lever being actuatable by means of a body entrainingthe breechblock mechanism and which body can be manually retracted.

3. The automatic firing weapon as defined in claim 2, wherein said breechblock mechanism includes a breechblock carrier, said body being arranged in a recess provided at an end face of the breechblock carrier and bearing under the pressure of a spring against a wall of the weapon housing.

4. The automatic firing weapon as defined in claim 3, wherein said body possesses a projection, said unlocking lever having a control surface, a spring for holding in bearing contact the unlocking lever by means of its control surface against said projection.

5. The automatic firing weapon as defined in claim 2, wherein said one-way coupling comprises a coupling element keyed with said shaft, and wherein said unlocking lever and said coupling element possess mutually contacting entrainment surfaces.

Claims

1. An automatic firing weapon comprising a housing, a weapon barrel movable relative to said housing, a breechblock mechanism including a breechblock displaceably mounted in said housing, a pivotable shaft, a safety lever pivotably mounted in the housing on said pivotable shaft, said breechblock having a stop, the safety lever in cooperative action with the stop at the breechblock preventing recoil movement of the breechblock, a control cam pivotally mounted in said housing on said pivotable shaft, the controL cam and said safety lever being connected with said pivotable shaft, an unlocking lever mounted on said pivotable shaft, means for placing said unlocking lever in driving connection with said pivotable shaft and means associated with said breechblock for manually actuating said unlocking lever, said barrel acting by means of a control surface thereon upon the control cam sliding upon said control surface for displacing the safety lever into a position releasing the breechblock after firing a shot.

2. An automatic firing weapon comprising a housing, a breechblock mechanism including a breechblock component displaceably mounted in said housing, a safety lever pivotably mounted in the housing, said breechblock component having a stop, the safety lever in cooperative action with the stop at the breechblock component preventing recoil movement of the breechblock component, a fire-moved component acting by means of a control surface upon the safety lever for displacing the safety lever into a position releasing the breechblock component after firing a shot, the improvement comprising the firing weapon possessing a weapon barrel defining the fire-moved component and movable relative to said housing, the control surface being arranged at the weapon barrel, the safety lever being provided with a control cam which slides upon the control surface, a common shaft upon which there are seated the control cam and said safety lever, the control cam and safetylever being connected with said common shaft, an unlocking lever, a one-way coupling means for placing into driving connection said unlocking lever with said common shaft, said unlocking lever being actuatable by means of a body entraining the breechblock mechanism and which body can be manually retracted.