Toggle Trigger

Abstract

A trigger mechanism for a firearm which has a light trigger pull, reliably contains the high forces of the firing pin spring and achieves this with a mechanism which is simple and with few parts. A toggle linkage prevents the firing pin retainer releasing the firing pin whilst still allowing a light pull. It contains no internal sear and no pins within the toggle mechanism. It is adjustable for variations in manufacturing and can cater for various levels of trigger pull force. It realizes considerable economies for production, assembly and repair without sacrificing functionality.

I claim: 
     
         1 . A trigger assembly for use with firearms comprising:
 a) Two sheets of material which act as an external chassis for internal parts;   b) A lower toggle which is pivotally attached to said sheet chassis;   c) A firing pin retainer which is pivotally attached to said sheet chassis;   d) An upper toggle being free floating and self-constrained between said lower toggle and said firing pin retainer with said upper toggle having pointed, near pointed or slightly radiused ends;   e) A toggle linkage being the combination of said lower toggle and upper toggle;   f) A geometric tipping line being a straight line between each end of said toggle linkage;   g) Said toggle linkage being a rigid set when arranged ante said tipping line;   h) A trigger shoe which is pivotally attached to said sheet chassis;   i) A trigger shoe adjustment screw attached to said trigger shoe;   j) Said trigger shoe adjustment screw being in operational communication with said toggle linkage;   k) A torsion spring being grounded at one end with the other end applying force to said toggle linkage;   l) Whereby when said trigger shoe is pulled causing said trigger shoe adjustment screw to move said toggle linkage forward and collapse said toggle linkage as toggle linkage is moved post said tipping line;   m) Whereby when said toggle linkage collapses said firing pin retainer rotates downward releasing firing pin and firing the firearm;   n) Whereby said trigger shoe adjustment screw may be adjusted to control bias between said toggle linkage and said tipping line;   o) Whereby adjustment of said trigger shoe adjustment screw introduces no lost motion.   
     
     
         2 ) The trigger assembly in accordance with  claim 1  further comprising of an overtravel adjustment screw for said trigger shoe. 
     
     
         3 ) The trigger assembly in accordance with  claim 1  further comprising of an undertravel adjustment screw for said trigger shoe. 
     
     
         4 ) The trigger assembly in accordance with  claim 1  further comprising of a firing pin retainer adjustment screw for adjustment of free-play in said toggle linkage. 
     
     
         5 ) The trigger assembly in accordance with  claim 1  in modified form comprising said torsion spring installed in an inverted position to increase force of trigger pull. 
     
     
         6 ) The trigger assembly in accordance with  claim 1  wherein the external chassis sheet may be profile cut from sheet material; 
     
     
         7 ) The trigger assembly in accordance with  claim 1  wherein internal parts being said lower toggle said upper toggle said trigger shoe and said firing pin retainer may be profile cut from plate material; 
     
     
         8 ) The trigger shoe adjustment screw of  claim 1  being able to be adjusted from beneath with the trigger in situ in the firearm; 
     
     
         9 ) The adjustment screw of  claim 2  being able to be adjusted from beneath with the trigger in situ in the firearm; 
     
     
         10 )The adjustment screw of  claim 3  being able to be adjusted from beneath with the trigger in situ in the firearm; 
     
     
         11 )The adjustment screw of  claim 4  being able to be adjusted from beneath with the trigger in situ in the firearm.