Patent Publication Number: US-8528241-B2

Title: Trigger mechanism for a firearm

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National Phase application of International Application No. PCT/AT2010/000150 filed May 6, 2010 which claims priority to Austrian Patent Application No. A 1020/2009 filed Jun. 30, 2009. 
     BACKGROUND 
     The present invention relates to a trigger device for a firearm with a spring-loaded firing pin that engages with a catch in the cocked position, the catch being releasable transversely to the direction of the firing pin in order to fire a shot, and displaceable along the direction of the firing pin, for safety purposes, between the cocked position and a safety position relieving the tension of the firing pin spring. 
     Movable catches for cocking and uncocking the firing pin spring are used for temporarily securing an already loaded weapon, e.g., for transport or while hunting. For this purpose, designs are known (e.g. AT 409 548 B) in which the catch is situated together with its initiator on a carriage that is movable in the housing and cooperates with the trigger. This type of carriage structure requires a number of moving parts, which has the disadvantage of an increased susceptibility to malfunctions and an increased space requirement. There are also known designs on the market in which the catch moves relative to its initiator when displaced, which impairs the precision of the shot trigger point and consequently also bears the risk of an unintended shot being fired if there is too little engagement overlap. 
     SUMMARY 
     The invention has the objective of overcoming the disadvantages of the prior art and creating a trigger device for a firearm that is simple and not susceptible to malfunction on the one hand and, on the other, allows an exact definition of when the shot is triggered. 
     This objective is achieved with a trigger device of the type mentioned above that is distinguished according to the invention in that the catch slides during displacement on an intermediate member that is movable in the direction of release of the catch, and engages with a click-stop edge of a trigger, which edge can be disengaged to fire a shot. 
     The triggering engagement, which is decisive for the release of the catch, is shifted in this manner from the catch to an intermediate member guided in the housing. This allows an exactly definable engagement overlap, independent of the displacement of the catch, for adjusting the trigger-press point. 
     The trigger is preferably seated in the housing of the firearm and bears on a shoulder the click-stop edge for the intermediate member, whereby the triggering point for firing a shot can be defined especially exactly. 
     It is particularly favorable if the intermediate member is a catch rod guided linearly in the housing of the firearm, which yields a simple structure. 
     According to another preferred embodiment of the invention, the catch slides on the intermediate member via an intercalated roller. This reduces the friction of the catch in its movement between the cocked position and the safety position, so that the cocked position can be reached with less exertion of force than with known solutions. 
     The roller is preferably located at the upper end of the catch rod, whereby the catch is simplified and reduced in weight. It is particularly favorable if the roller is seated with a ball bearing, in order to reduce friction even further. 
     According to another advantageous embodiment of the invention, it is provided that the extent of the engagement overlap of the intermediate member with the click-stop edge of the trigger is adjustable by means of an adjustment screw. Thereby the trigger point of the weapon can be adjusted, independently of the positions of the catch. 
     It is particularly favorable if the catch can be moved between the cocked position and the safety position by a cocking slide that acts on the actuation element via a linkage, as is known from prior art. Alternatively, the catch could also be actuated by a cocking wheel via a suitable linkage. 
     The trigger device according to the invention is suitable for any type of firearm with a firing pin and a catch that can be moved for safety purposes. Preferably, however, the firearm is a semiautomatic weapon with a rotary piston action and in particular, the firing pin engages with the catch by means of an attached firing pin tab; for these types of weapon, the trigger device of the invention leads to particularly low overall height and easy integration. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in detail below with reference to an embodiment example illustrated in the attached drawings. In the drawings: 
         FIGS. 1-3  show the trigger device of the invention in cross section in the safety position ( FIG. 1 ), the cocked position ( FIG. 2 ) and the position after firing ( FIG. 3 ). 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1-3  show the rear part of a firing pin  1 , a trigger device  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 rifle barrel and is guided for this purpose in a rotary piston, which parts are known to those in the art and are therefore not shown in detail here. 
     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 point  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 first be released from the firing pin  1  by means of the trigger device  2  to fire a shot, so that the pin moves to the left by the force of the firing pin spring  5  to collide with the cartridge (see position after firing in  FIG. 3 ); second, the catch  8  can thus be moved or displaced in the longitudinal direction between two 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  (with a rotary piston action, the firing pin  1  can be brought into this position by an ordinary chamber stem during the loading or repeating process); and 
     an uncocked safety ( FIG. 1 ) in which the catch  8  is displaced to the left, 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 device  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 a click-stop edge  13  formed on a shoulder  14  of the trigger  15 . The trigger  15  is pivotably seated at  16  on the housing  4  and when actuated moves the click-stop 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 click-stop edge  13  of the trigger  15  can be adjusted by means of an adjusting screw  17 . 
     The trigger  15  with its click-stop 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 click-stop 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 in the art. 
     The cocking and uncocking mechanism  3  comprises an actuator element  21  in the form of a cocking slide  21  seated slidably 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. 
     When the cocking slide  21  in  FIGS. 1 and 2  is moved from right to left, 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 . With the aid of a pushbutton  36  on the cocking slide  21 , a self-locking latch  37  for locking the connecting rod  26  in the cocked position C can again be disengaged. 
     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.