Collapsible butt-stock mechanism for shoulder-fired firearms

Abstract

A firearm has a receiver extension defining a plurality of spaced butt-stock positioning receptacles. A butt-stock has a locking pin that is moveable into one of the receptacles for locking the butt-stock at a desired position on the receiver extension. A lock pin actuator is manually moveable by applying a force to a pull ring member to cause retraction of the locking pin from a butt-stock positioning receptacle in preparation for position adjustment or removal of the butt-stock relative to the receiver extension. A rotary knob lock positioning member is rotatable to locked and unlocked positions and when locked ensures against complete separation of the butt-stock from the receiver extension member upon maximum length adjustment of the butt-stock.

I claim: 
     
         1 . An adjustable butt-stock mechanism for a shoulder fired firearm, comprising:
 a receiver extension member being mounted to a firearm receiver and having an elongate boss member defining a plurality of spaced position adjustment recesses along the length thereof;   a butt-stock body defining a receiver extension passage within which said receiver extension member is movably received and selectively positioned, said butt-stock body defining a lock passage and having a web portion defining a pull member opening;   a locking pin being movably located within said lock passage and having a portion thereof being located within said receiver extension passage and having selective locking engagement within a selected one of said spaced position adjustment recesses;   a locking pin actuator having force transmitting engagement with said locking pin and upon being manually moved causing unlocking movement of said locking pin from said spaced position adjustment recesses; and   a trigger-like pull member being located within said pull member opening and having connection with said locking pin actuator and being disposed for application of manual pulling force by a user to cause unlocking movement of said locking pin actuator and said locking pin.   
     
     
         2 . The adjustable butt-stock mechanism of  claim 1 , comprising:
 an urging member continuously urging said locking pin toward said locking position thereof; and   said locking pin actuator overcoming said urging member and moving said locking pin toward an unlocking position with said locking pin extracted from said spaced position adjustment recesses.   
     
     
         3 . The adjustable butt-stock mechanism of  claim 1 , comprising:
 said locking pin having a cam engagement surface; and   said locking pin actuator having a tapered cam surface in engagement with said cam engagement surface and upon being moved linearly by a manually energized pulling, force causing unlocking movement of said locking pin.   
     
     
         4 . The adjustable butt-stock mechanism of  claim 1 , comprising:
 a manually positionable locking selector being mounted to said locking pin actuator and having a first selector position limiting unlocking movement of said locking pin by said locking pin actuator and a second selector position permitting complete unlocking movement of said locking pin by said locking pin actuator for complete separation of said adjustable butt-stock from said receiver extension member.   
     
     
         5 . The adjustable butt-stock mechanism of  claim 4 , comprising:
 a locking position element being mounted to said manually positionable locking selector and establishing a locking reference; and   said manually positionable locking selector having a selector shaft being moveable to a first position having movement limiting contact with said locking position element and limiting linear unlocking movement of said locking pin actuator and being moveable to a second position permitting complete unlocking movement of said locking pin.   
     
     
         6 . The adjustable butt-stock mechanism of  claim 5 , comprising:
 said locking position element being a pin member mounted to said locking pin actuator;   said selector shaft having a bifurcated end portion defining a recess receiving said locking position element when said selector shaft is situated at said first position; and   a manually operable selector knob being mounted to said selector shaft and having first and second rotational positions having 90° rotational spacing.   
     
     
         7 . The adjustable butt-stock mechanism of  claim 1 , comprising:
 a manually positionable locking selector being mounted to said locking pin actuator and having a first selector position limiting unlocking movement of said locking pin by said locking pin actuator and a second selector position permitting complete unlocking movement of said locking pin by said locking pin actuator for complete separation of said adjustable butt-stock from said receiver extension member;   a locking position element being mounted to said manually positionable locking selector and establishing a locking reference; and   said manually positionable locking selector having a selector shaft being moveable to a first position having movement limiting contact with said locking position element and limiting linear unlocking movement of said locking pin actuator and being moveable to a second position permitting complete unlocking movement of said locking pin.   
     
     
         8 . The adjustable butt-stock mechanism of  claim 1 , comprising:
 a lock actuator passage being defined within said butt-stock body;   said locking pin actuator being linearly moveable within said lock actuator passage responsive to application of a pulling force thereto;   a lock selector shaft being rotationally moveable within said locking pin actuator; and   a lock selector knob being mounted to said lock selector shaft and being manually rotatable to a first position limiting linear unlocking movement of said locking pin actuator and being moveable to a second position permitting complete unlocking movement of said locking pin.   
     
     
         9 . The adjustable butt-stock mechanism of  claim 8 , comprising:
 a spring member urging said lock selector shaft against an internal stop shoulder of said locking pin actuator and yielding to permit rotational lock positioning movement of said lock selector shaft.   
     
     
         10 . The adjustable butt-stock mechanism of  claim 9 , comprising:
 said locking in actuator defining a pair of detent recesses having 90° rotational spacing;   a spring urged detent member being supported by said lock selector knob and being disposed for selective engagement within said detent recesses and establishing said first and second locking positions of said locking pin.   
     
     
         11 . An adjustable butt-stock mechanism for a shoulder fired firearm, comprising:
 a receiver extension member being mounted to a firearm receiver and having an elongate boss member defining a plurality of spaced position adjustment recesses along the length thereof;   a butt-stock body defining a receiver extension passage within which said receiver extension member is movably received and selectively positioned, said butt-stock body defining a lock passage and having a web portion defining a pull member opening;   a locking pin being movably located within said lock passage and having a portion thereof being located within said receiver extension passage and having selective kicking engagement within a selected one of said spaced position adjustment recesses;   a locking pin actuator having force transmitting engagement with said locking pin and upon being manually moved causing unlocking movement of said locking pin from said spaced position adjustment recesses;   a trigger-like pull member being located within said pull member opening and having connection with said locking pin actuator and being disposed for application of manual pulling force by a user to cause unlocking movement of said locking pin actuator and said locking pin;   a locking position element being mounted to said manually positionable locking selector and establishing a locking reference; and   said manually positionable locking selector having a selector shaft being moveable to a first position having movement limiting contact with said locking position element and limiting linear unlocking movement of said locking pin actuator and being moveable to a second position permitting complete unlocking movement of said locking pin.   
     
     
         12 . The adjustable butt-stock mechanism of  claim 11 , comprising:
 an urging member continuously urging said locking pin toward said locking position thereof; and   said locking pin actuator overcoming said urging member and moving said locking pin toward an unlocking position with said locking pin extracted from said spaced position adjustment recesses.   
     
     
         13 . The adjustable butt-stock mechanism of  claim 11 , comprising:
 said locking pin having a cam engagement surface; and   said locking pin actuator having a tapered cam surface in engagement with said cam engagement surface and upon being moved linearly by a manually energized pulling force causing unlocking movement of said locking pin.   
     
     
         14 . The adjustable butt-stock mechanism of  claim 11 , comprising:
 a manually positionable locking selector being mounted to said locking pin actuator and having a first selector position limiting unlocking movement of said locking pin by said locking pin actuator and a second selector position permitting complete unlocking movement of said locking pin by said locking pin actuator for complete separation of said adjustable butt-stock from said receiver extension member.   
     
     
         15 . The adjustable butt-stock mechanism of  claim 14 , comprising:
 a locking position element being mounted to said manually positionable locking selector and establishing a locking reference; and   said manually positionable locking selector having a selector shaft being moveable to a first position having movement limiting contact with said locking position element and limiting linear unlocking movement of said locking pin actuator and being moveable to a second position permitting complete unlocking movement of said locking pin.   
     
     
         16 . The adjustable butt-stock mechanism of  claim 15 , comprising:
 said locking position element being a pin member mounted to said locking pin actuator;   said selector shaft having a bifurcated end portion defining a recess receiving said locking position element when said selector shaft is situated at said first position; and   a manually operable selector knob being mounted to said selector shaft and having first and second rotational positions having 90° rotational spacing.