Abstract:
The invention relates to a cocking and uncocking mechanism for a firearm, comprising a spring-loaded firing pin which, when in the cocked position, engages on a catch that can be released to fire, said catch being displaceable by an actuator element acting upon the catch via a link motion the control cam of which maintains the force to be applied to the actuator element to displace the catch to the cocked position substantially constant at least in the center region of the actuation path.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Phase application of International Application No. PCT/AT2010/000149 filed May 6, 2010 which claims priority to Austrian Patent Application No. A 1019/2009 filed Jun. 30, 2009. 
     BACKGROUND 
     The present invention relates to a cocking and uncocking mechanism for a firearm with a spring-loaded firing pin that engages with a catch that can be released to fire in the cocked position, the catch being displaceable by an actuator element between the cocked position and a safety position uncocking the firing pin spring. 
     Such cocking and uncocking devices are used particularly for temporarily securing an already loaded weapon, e.g., for transport or while hunting. To leave the safety position, the catch must be recocked against the force of the firing pin spring, which is why such safety devices are simultaneously used as “handcocking systems.” 
     In known designs (z.B. AT 409 548 B), the actuator element is connected to the catch by a lever linkage, with which the force for cocking the firing pin spring is exerted. This has the disadvantage that the force F to be exerted on the actuator element, corresponding to the spring characteristic of the firing pin, increases approximately linearly with the actuation length S, as illustrated in the diagram of  FIG. 4 . This renders usage of the actuator element, e.g., a cocking slide or wheel, extremely laborious. Moreover, the actuation force is greatest precisely in the area around the cocked position, which makes actuation of a catch or release device for engaging or disengaging the actuator element in the cocked position more difficult. 
     SUMMARY 
     The invention has the objective of creating a cocking and uncocking mechanism of the type mentioned above with easier operation. This objective is achieved according to the invention by virtue of the fact that the actuator element acts on the catch via a motion link, whose control cam holds the force to be exerted onto the actuator element to move the catch into the cocked position approximately constant in the central area of the actuation path. 
     In this manner, usage of the actuator element, e.g., a cockling slide or wheel, is considerably facilitated for the user. The transmission ratio of the lever linkage between the actuator element and the catch can be path-independently defined in advance with the aid of the motion link, specifically in such a manner that the actuation force remains largely constant for the user across the central section of the actuation path. After a slight build-up of actuation force to the level required for enabling easy initial movement, there is therefore no increasing difficulty, which allows a simplified and fast cocking process. 
     It is particularly favorable if, according to a preferred characteristic of the invention, the control cam reduces the force to be exerted onto the actuation element to shift the catch into the cocked position in the terminal area of the actuation path before the cocked position is reached. This can facilitate the operation of a catch or release element for locking or releasing the cocked position, because the actuator element need only be retained with a small exertion of force in this area. In addition, the cocking process can become carried out with much less noise than with known designs, because the cocked position can be reached with less exertion of force, almost “cautiously.” 
     A preferred embodiment of the invention is distinguished in that the control cam is formed on the periphery of a pivoting crank driven by the actuator element and is sensed by a sensing linkage driving the catch, thus taking up only a small overall space. 
     It is particularly favorable if the sensing linkage is equipped with a preferably ball-bearing seated cam follower that rolls over the periphery of the control cam, whereby the friction of the motion link, and thus the required actuation force, can be considerably reduced. 
     The sensing linkage preferably engages with an auxiliary linkage guide of the motion link in order to keep the cam follower in contact with the control cam during the return motion to the safety position. Operating malfunctions due, for example, to increased friction from contamination and so forth can be avoided in this manner. 
     In another advantageous configuration of the invention, the sensing linkage comprises a linearly movable sensing rod that follows the control cam at one end and drives the catch at the other end, preferably via a housing-seated two-armed lever, which enables a particularly compact design with low space requirements. 
     The actuator element can be of any type known in the art, such as a cocking slide or a cocking wheel. The actuator element is preferably a cocking slide, which especially preferably locks in the cocked position and can be detached from the locking by means of a pushbutton. This known design of a cocking slide enables an operation and locking in the cocked position that are particularly immune to malfunctions and an easy transition into the safety position. 
     The cocking and uncocking mechanism of the invention is suitable for any type of firearm with a spring-loaded firing pin. The use of the invention is especially advantageous for semiautomatic weapons with a rotary piston action, and particularly for weapons whose firing pins have an attached firing pin tab that engages with the catch, because the cocking and uncocking mechanism of the invention can be mounted directly without additional parts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in detail below with reference to an exemplary embodiment illustrated in the attached drawings. In the drawings: 
         FIGS. 1-3  show the cocking and uncocking mechanism of the invention in cross-section in the safety position ( FIG. 1 ), the cocked position ( FIG. 2 ) and the position after firing ( FIG. 3 ); and 
         FIGS. 4 and 5  show the force/distance diagram of a mechanism according to the prior art ( FIG. 4 ) and a mechanism according to the invention ( FIG. 5 ). 
     
    
    
       FIGS. 1-3  show the rear part of a firing pin  1 , a trigger mechanism  2 , a cocking and uncocking mechanism  3  and (in part) a housing  4  of a firearm (not shown in further detail). The firing pin  1  acts on a cartridge in the chamber of a muzzle and is guided for this purpose in a rotary piston, which parts are known to those skilled in the art and are therefore not shown in detail here. 
     DETAILED DESCRIPTION 
     The firing pin  1  is subjected to a force to the left in the drawing by a firing pin spring  5  (indicated schematically) and is engaged with a firing pin tab  6  at  7  on a catch  8 . The catch  8  is seated movably, in both the longitudinal and the transverse directions of the firing pin, by a bearing journal  9  in elongated holes of the housing  4 . Thus the catch  8  can be released on the one hand to enable a shot by the firing pin  1  by means of the trigger mechanism  2 , so that the firing pin moves to the left under the force of the firing pin spring  5  to strike the cartridge (see position after firing in  FIG. 3 ); on the other hand the catch  8  can also be moved or displaced back and forth in the longitudinal direction of the firing pin between two different positions, specifically 
     an unsecured or cocked position ( FIG. 2 ), in which the catch holds the firing pin  1  cocked against the force of the firing pin spring  5  (in case of a rotary piston action, the firing pin  1  can also be brought into this position during the repeating or loading process by means of a conventional bolt handle); and 
     an uncocked safety position ( FIG. 1 ) in which the catch  8  is displaced to the left in the drawing in order to relieve the tension of the firing pin spring  5  (a slight residual tension can be left in the firing pin spring  5  in order to move the front part of the firing pin  1 —not shown here—slightly away from the bottom of the cartridge). 
     In this respect, the catch  8  is a part of the trigger mechanism  2  as well as the cocking and uncocking mechanism  3 . 
     To absorb the above-mentioned displacement motion of the catch  8 , the trigger mechanism  2  comprises an intermediate element in the form of a catch rod  10  that is linearly guided in the housing  4  approximately vertically and supports a ball bearing-seated roller  11  at its upper end, on which the catch  8  can slide back and forth. The catch rod  10  in turn is engaged at a shoulder  12  on an engagement edge  13  formed on a shoulder  14  of a trigger  15 . The trigger  15  is pivotably seated at  16  on the housing  4  and when actuated moves the engagement edge  13  away from the catch rod  10 , so that the latter is moved downward ( FIG. 3 ) and releases the catch  8  from the firing pin  1 , whereby the shot is fired. The extent of the engagement overlap between the shoulder  12  of the catch rod  10  and the engagement edge  13  of the trigger  15  can be adjusted by means of an adjusting screw  17 . 
     The trigger  15  with its engagement edge  13  can be integrally formed or —as shown—as two parts adjustable relative to one another, such as a first part comprising a trigger blade  18  and a second part comprising the shoulder  14  with the engagement edge  13 . The trigger  15  can further be equipped with a drop guard  19  and a bolt catch  20  for triggering a rotary piston action, as known to those skilled in the art. 
     The cocking and uncocking mechanism  3  comprises an actuator element  21  in the form of a cocking slide  21  slidably seated on the outside of the housing  4  with a thumb-press surface  22 , which acts via a linkage  23  on the catch  8  in order to move it back and forth in the longitudinal direction of the firing pin between its two positions ( FIGS. 1 and 2 ). The linkage  23  contains a motion link  24 , via which the force/distance transmission ratio between the actuator element  21  and catch  8  can be adjusted. 
     The motion link  24  comprises a pivoting crank  25  that can be pivoted by the cocking slide  21  via a connecting rod  26  and bears a control cam  27  on its outer periphery. A sensing linkage  28  with a ball bearing-seated cam follower  29  rolls over the control cam  27  and translates the shape of the control cam  27  into a movement of the catch  8  via a housing-seated two-armed lever  30  that engages with a pin  31  of the catch  8 . 
     The pivoting crank  25  is also equipped with an auxiliary linkage guide  32  in the form of a groove guide that is located behind the control cam  27  and with which the sensing linkage  28  engages by means of a retaining pin  33  projecting past the cam follower  29 . Thereby a forced contact of the cam follower  29  on the control cam  27  is assured in every operating state. 
       FIG. 5  shows the force/distance transmission ratio of the motion link  24 , where R designates the uncocked or safety position of  FIG. 1  and C designates the unsecured or cocked position of  FIG. 2 . When the cocking slide  21  is moved from R to C (from right to left in  FIGS. 1 and 2 ), the pivoting crank  25  swings downward, the sensing link  28  slides to the left on the control cam  27  and the catch  8  is moved to the right by the lever  29  against the force of the firing pin spring  5 . As is evident from  FIG. 5 , the slope of the control cam  27  is selected in such a manner that the force F to be exerted on the actuator element  21  is substantially constant at least in a central area  34  of the actuation path R-C of the cocking slide  21 , in order to facilitate the operation of the cocking slide  21 . 
     Optionally, the control cam  27  is preferably also selected in such a manner that the force F to be exerted diminishes further in the terminal area  35  of the actuation path R-C before the cocked position C. This enables a “cautious,” soundless achievement of the cocked position C. It also facilitates the operation of a pushbutton  36  on the cocking slide  21  with which a self locking latch  37  for locking the connecting rod  26  in the cocked position C can be disengaged. 
     It is understood that, in place of the pivoting crank  25  as shown, any other motion link  23  fulfilling the above-mentioned transmission function can be used, such as a kinematic reversal with a control cam on the catch and a sensing linkage on the actuator element, etc. Furthermore, all rotary or pivot bearings in the mechanism can preferably be implemented by means of rolling contact bearings in order to reduce friction. 
     The invention is accordingly not limited to the illustrated embodiments, but instead comprises all variants and modifications that fall within the scope of the appended claims.