EP0689026B1 - System to brake the movement of the hammer in a firearm - Google Patents

Abstract

The braking component (20) turns about a pivot (36) and is linked to the component (10) being braked by a rod (22) which extends perpendicular to the components' two pivots (12,36). The rod is pivoted to the braked component and passed freely through an aperture (40) in the braking component, while an arming spring (14) is fitted around the rod and applies a pressure to the braking component. The two pivots are situated at different distances from the axis of the rod to provide two opposite thrust forces on the ends of the braking and braked components, with the latter in the form of a hammer in a small calibre firearm. <IMAGE>

Description

The present invention relates to a method for braking the movement of a part armed by a spring and animated by a reciprocating swivel movement.

The field of application of the invention is in particular, but not exclusively, that of the automatic firearms of small caliber, the part to be braked being the hammer of the weapon operating mechanism.

A firearm of the above type can operate at one rate of 1200 strokes / min, for example, and the problem posed is to be able to reduce such a rate of fire for notably increase the accuracy of the weapon's shooting.

Until now, slowdown systems of the rate of fire of a small automatic firearm caliber are based on the inertia of launched flyweights or on clock systems. In the case of weights launched, a large volume is required to ensure moving the weights, while a system is of great complexity, so that none of these two systems are not easy to implement.

The patent US2791942 thus describes such a system of slowdown of firing using a clockwork device. This system is applied to an automatic weapon comprising a hammer with an alternating pivoting movement between a cocking position and a percussion position. This patent is taken as the basis of the preamble of claim 1.

The object of the invention is to provide a solution new to the problem of slowing down an animated play of a reciprocating pivoting movement, such as the hammer of a firearm, and whose implementation is simple and little expensive.

To this end, the invention provides a method for slow down the movement of a part subjected to the action of a spring and driven by an alternating pivoting movement between a first and a second position, the part being subjected to a first couple resulting from exercise at a first point of application on said part of the force of relaxation exerted by the spring in the banded state, to drive moving the piece from its first to its second position, part returning to its first position under the action of a other driving member, process characterized in that it consists to apply to this part a second couple having a value lower than the first, to slow the movement of the piece, second couple applied to it through a second pivoting part bearing on the part to brake on at least part of the travel stroke of the latter between its first and its second position to oppose the action of the aforementioned first couple, second part whose support on the first part is caused by the spring expansion force applied to it at the level a second point of application on said second part.

The invention also relates to a system for setting using this method, system which is characterized in that that it includes a second piece or braking piece mounted swivel around a shaft and connected to the part to be braked at by means of a connecting rod extending perpendicularly to the two articulation shafts of the two parts, the rod link being articulated on the part to be braked and passing through freely opening the braking part, the spring armament being mounted around the rod and resting on the braking part and a boss provided in the middle part of the rod, and in that the two articulation shafts are located at different distances from the axis of the rod connection so that the return force of the arming spring, at the bandaged state when the part to be braked is in its first position, or simultaneously applied to the two parts in giving birth to two opposing pairs to slow down the movement of the part over at least part of the stroke moving to its second position.

In general, the method and the system according to the invention can be applied to a firearm small caliber, where the part to be braked is the hammer of the operating mechanism of this weapon.

Thus, it is possible to reduce the rate of firing the weapon to increase the accuracy of shooting, without fundamentally change the mechanism of the weapon.

• la figure 1 est une vue schématique, avec arrachement partiel, d'une arme à feu dont le mécanisme est équipé d'un système de freinage selon l'invention, et
• les figures 2 et 3 sont des vues schématiques de principe pour illustrer le fonctionnement du système illustré à la figure 1.

Other advantages, characteristics and details of the invention will emerge from the explanatory description which follows, given with reference to the appended drawings, given solely by way of example and in which:

• FIG. 1 is a schematic view, with partial cutaway, of a firearm whose mechanism is equipped with a braking system according to the invention, and
• Figures 2 and 3 are schematic views in principle to illustrate the operation of the system illustrated in Figure 1.

Firearm 1, as shown schematically in Figure 1, is an automatic weapon of small caliber comprising a barrel assembly 2, a stock 4 in which is housed a mechanism 5 of weapon operation control, trigger 7 connected to mechanism 5 and a handle 9 to support weapon 1.

The mechanism 5 includes in particular a hammer 10 mounted to pivot around a supported shaft 12 in rotation by the body of the weapon 1. This hammer 10 is animated by an alternating pivoting movement between a cocking position and a percussion position, when the trigger 7 is pressed by the shooter's finger.

In general, the hammer 10 is armed by a spring 14 when it is in its position weapon, and it cooperates with a trigger (not shown), controlled by trigger 7 and which maintains hammer 10 in cocking position as long as the trigger is not activated.

A braking system 15 makes it possible to slow down the movement of the hammer 10 during its movement towards its percussion position under the action of the force exerted by the arming spring 14, once the trigger is no longer engaged with the hammer 10.

This braking system 15 is based on the action exerted on the hammer 10 by two opposite couples or antagonists which are applied simultaneously to the hammer 10 and defined from the force exerted by the spring 14.

More specifically, with reference to FIGS. 2 and 3, the braking system comprises a braking part 20 intended to come to rest on the hammer 10 when this the latter is in the arming position. A first couple C1 is applied to hammer 10, while a second pair antagonist C2 (C2 <C1) is simultaneously applied by the braking piece 20 on the hammer 10.

To this end, the braking system 15 comprises a connecting rod 22 mounted between the hammer 10 and the workpiece braking 20. This connecting rod 22 supports the spring arming 14 so that the force of this spring 14, simultaneously applied to the hammer 10 and the braking part 20, generates the aforementioned two pairs C1 and C2.

The hammer 10 comprises a body 24, one end of which is articulated on the shaft 12 and the other end of which forms a percussion element 26. A bearing surface 28 is formed by a shoulder-shaped recess between the body 24 and the percussion element 26 of the hammer 10.

The braking part 20 comprises a body 30, one of which end forms a bearing surface 32 and the other of which end extends, substantially at 90 °, by a tail 34 located in the same plane as the body 30. The braking part 20 is pivotally mounted around a shaft 36 supported by the weapon body 1 and parallel to the pivot shaft 12 of the hammer 10.

The hammer 10 and the braking piece 20 are positioned in the same plane parallel to the plane of symmetry of weapon 1 passing through the barrel assembly 2.

The connecting rod 22 of the retarder device 15 is mounted articulated, at one end, with the hammer 10 on a shaft 38 parallel to the pivot shafts 12 and 36 of the hammer 10 and brake piece 20, while its other end freely passes through an opening 40 pierced in the tail 34 of the braking piece 20. A collar or boss 42 is provided in the central part of the connecting rod 22, and the arming spring 14 of the hammer 10 is mounted around the rod 22 so that its two ends take respectively support on the boss 42 and on the part braking 20.

The force of spring 14 is therefore applied simultaneously on hammer 10 at an application point materialized by the shaft 38 mounted between the hammer 10 and the rod 22, and on the braking part 20 at a point located at tail level 34 of his body 30. These two points are located on the longitudinal axis X-X of the connecting rod 22, and the pivot axes of the hammer 10 and of the braking part 20, materialized by the shafts 12 and 36, are respectively located at distances D1 and D2 (D1> D2) of the X-X axis.

Referring to Figure 3, there will be described the operating principle of the retarder device 30.

When the hammer 10 is in its cocking position, its bearing surface 28 is in contact with the bearing surface 32 of the braking part 20, and the spring 14 is in the state bandaged. The force of this spring 14 is applied simultaneously and with the same intensity on the hammer 10 and on the workpiece braking 20. This force gives birth to the first couple C1 which is applied to hammer 10 and which tends to do so rotate towards its percussion position, and gives birth at second antagonistic couple C2 which is also applied on hammer 10 through the workpiece braking 20 and which tends to oppose the action exerted by the couple C1. Under these conditions, as long as the piece brake 20 rests on hammer 10, the torque resulting applied to the hammer 10 is equal to the difference of the two couples C1 and C2, so that the hammer movement 10 is slowed down on at least one part of its displacement travel to its position of percussion. The bearing surfaces 28 and 32 of the hammer 10 and of the braking part 20 are dimensioned so to stay in contact with each other on at least one part of the travel stroke of the hammer 10. In playing on the dimensioning of these surfaces 28 and 32, as well as on the value of the pairs C1 and C2, we can adjust the hammer deceleration speed 10.

The return movement of the hammer of its percussion position to its arming position, is obtained for example by the movement of the breech of the mechanism 5 of the weapon.

Generally speaking, this braking 15 of which an application example has been given in the case of an operating mechanism of a handgun fire, can of course be applied to other areas where it is necessary to slow down the movement swivel in one piece.

Claims (3)

1. A process to brake the movement of a part (10) cocked by a spring (14) and having an alternating swivelling movement between a first and a second position, this part being subjected to a first torque defined near a first application point on said part by the strain-release force exercised by the spring, in its tensed position, to impart a movement to the part from its first to its second position, said part thereafter coming back into its first position under the action of another driving organ, characterised by the fact that one applies to this part a second torque with a value less than the first torque, to slow down the movement of the part, said second torque being applied on it by a second swivelling part (20) coming in contact with the part to brake along at least one part of its course from its first to its second position, in opposition to the action of the afore-mentioned first torque, said second part which support against the first part is generated by the strain-release force of the spring (14) which is applied on a second application point on said second part.
2. A system for the implementation of the process according to claim 1, in order to brake down the movement af a part (10) cocked by a spring (14) and having an alternating swivelling movement around a shaft (12) between a first and a second position, characterised in that it comprises a second part (20) or braking part, mounted swivelling around a shaft (36) and linked to the part (10) to be braked by means of a linking rod (22) extending perpendicularly to the two pivot shafts (12, 36) of the two parts (10, 20), the linking rod (22) being hinged to the part (10) to be braked and freely passing through an opening (40) in the braking part (20), the cocking spring (14) being mounted around the rod (12) and bearing respectively on the braking part (20) and on a boss (35) located on the median field of the linking rod (22), and in that the two pivot shafts (12, 36) are located at different distances (D1, D2) from the longitudinal axis (X-X) of the linking rod (22) so that the restoring force of the cocking spring (14), in its tensed position when the part (10) to be braked is in its first position, is applied simultaneously to the two parts (10, 20) thereby creating two opposing torques (C1, C2) to slow down the movement of the part (20) to be braked along at least one part of its course towards its second position.
3. A system according to Claim 2, characterised in that the part to be braked (10) is the hammer of a functioning mechanism for a small-calibre firearm.

Images