Firearm bolt having dead stop ejector pin

Abstract

A bolt mechanism for gas operated auto-cycling firearms is provided with a spring urged ejector having a geometry that provides a dead stop to limit excessive ejector movement and force that might otherwise damage or cause excessive wear of the ejector. The bolt member defines an ejector receptacle having an enlarged receptacle portion of oval configuration having the radial width of a standard ejector and defining an internal dead stop shoulder. The ejector member has limited linear movement within its receptacle and has a corresponding stop shoulder that is positioned for engagement with the internal stop shoulder and serves to positively stop ejector movement if the ejector is subjected to excessive force.

I claim: 
     
         1 . A bolt member for a firearm, comprising:
 a bolt body defining a bolt locking head having a generally circular internal wall surface defining a cartridge recess having a generally planar bolt face surface within said cartridge recess;   an ejector bore of predetermined diameter being defined within said bolt body and having substantially perpendicular relation with said generally planar bolt face surface, a portion of said ejector bore defining a spring chamber;   an ejector pocket being defined within said bolt body and about said ejector bore and having a radial dimension substantially the same as said predetermined diameter and a lateral dimension exceeding said radial dimension;   an ejector member having a shaft portion of a defined diameter being movably received within said ejector bore and having an ejector head extending from said ejector shaft portion band being movably received within said ejector pocket, said ejector head defining a stop surface;   a stop shoulder being defined within said ejector pocket and being engaged by said stop surface of said ejector head to limit propellant pressure responsive linear movement of said ejector member; and   a spring member being located within said spring chamber and being engaged by said shaft portion of said ejector member, said spring member urging said ejector member forwardly to apply ejecting force to a cartridge seated within said cartridge recess.   
     
     
         2 . The bolt member of  claim 1 , comprising:
 said ejector head having a radial dimension being substantially the same as the dimension of the shaft portion of a conventional ejector member and having a lateral dimension exceeding the generally cylindrical cross-sectional dimension of a conventional ejector member.   
     
     
         3 . The bolt member of  claim 2 , comprising:
 said cartridge recess having a generally circular internal wall surface;   said ejector pocket having an outer wall surface intersecting said internal wall surface of said cartridge recess; and   said ejector head being of oval configuration and defining oppositely facing curved end surfaces and having oppositely facing side surfaces, one of said side surfaces engaging said outer wall surface of said ejector pocket.   
     
     
         4 . The bolt member of  claim 1 , comprising:
 said shaft portion of said ejector member having a longitudinal center-line; and   said ejector head having a longitudinal centerline being co-extensive with said longitudinal center-line of said shaft portion.   
     
     
         5 . The bolt member of  claim 1 , comprising:
 said shaft portion of said ejector member defining an elongate lateral recess having forward and rearward recess end surfaces;   an ejector retainer pin extending through said bolt body and having a portion thereof positioned within said elongate lateral recess; and   during propellant pressure responsive rearward movement of said ejector member said stop surface of said ejector head contacting said stop shoulder of said ejector head pocket limiting further rearward movement of said ejector member to prevent damage to said retainer pin and prevent excessive compression of said ejector spring.   
     
     
         6 . The bolt member of  claim 5 , comprising:
 said retainer pin being of circular cross-sectional configuration and having an external surface of defined curvature; and   said rearward recess end surface of said lateral recess of said shaft portion of said ejector member having an internal curvature matching said defined external curvature of said retainer pin and providing for surface to surface engagement thereof ensuring optimum force transmission of said rearward recess end surface of said lateral recess with said ejector retainer pin.   
     
     
         7 . The bolt member of  claim 1 , comprising:
 said ejector head and said shaft portion of said ejector member being of integral one-piece construction;   said ejector head having a generally planar forward end surface having a non-circular configuration being defined by oppositely facing end surfaces and oppositely facing side surfaces; and   said ejector head and said shaft portion of said ejector member having a common longitudinal center-line.   
     
     
         8 . The bolt member of  claim 1 , comprising:
 said cartridge recess having a generally circular internal wall surface;   said ejector pocket having an outer wall surface intersection said internal wall surface of said cartridge recess; and   said ejector head being of oval configuration and defining oppositely facing curved end surfaces and oppositely facing side surfaces, one of said side surfaces having intersection with said generally cylindrical internal wall surface of said cartridge recesss and having a part thereof projecting outwardly beyond said generally cylindrical internal wall surface.   
     
     
         9 . The bolt member of  claim 1 , comprising:
 said bolt body defining a longitudinal center-line;   a longitudinal firing pin passage located substantially centrally of said bolt body along said longitudinal center-line and having a passage opening intersecting said generally planar bolt face surface; and   said ejector bore defining a longitudinal bore center-line having substantially parallel relation with said longitudinal center-line of said bolt body.   
     
     
         10 . A bolt member for a firearm, comprising:
 a bolt body defining a bolt locking head having a generally circular internal wall surface defining a cartridge recess and having a generally planar bolt face surface within said cartridge recess, said bolt body having a longitudinal center-line;   an ejector bore of predetermined diameter being defined within said bolt body and having substantially perpendicular relation with said generally planar bolt face surface, said ejector bore having a longitudinal center-line in substantially parallel relation with said longitudinal center-line of said bolt body, a portion of said ejector bore defining a spring chamber;   an ejector pocket being defined within said bolt body and about said ejector bore and having a radial dimension substantially the same as said predetermined diameter and a lateral dimension exceeding said radial dimension;   an ejector member having a shaft portion of a defined diameter being movably received within said ejector bore and having an ejector head extending from said ejector shaft portion band being movably received within said ejector pocket, said ejector head defining a stop surface;   a stop shoulder being defined within said ejector pocket and being engaged by said stop surface of said ejector head to limit propellant pressure responsive linear movement of said ejector member; and   an ejector spring member being located within said spring chamber and being engaged by said shaft portion of said ejector member and resisting propellant pressure responsive rearward movement of said ejector member, said spring member urging said ejector member forwardly to apply ejecting force to a cartridge seated within said cartridge recess.   
     
     
         11 . The bolt member of  claim 10 , comprising:
 said ejector head having a radial dimension being substantially the same as a cylindrical shaft of a conventional ejector member and having a lateral dimension exceeding the cylindrical cross-sectional dimension of a conventional ejector member.   
     
     
         12 . The bolt member of  claim 11 , comprising:
 said cartridge recess having a generally circular internal wall surface;   said ejector pocket having an outer wall surface intersection said internal wall surface of said cartridge recess; and   said ejector head being of oval configuration and defining oppositely facing curved end surfaces and oppositely facing side surfaces, one of said side surfaces having intersection with said generally cylindrical internal wall surface of said cartridge recess and having a part thereof projecting outwardly beyond said generally cylindrical internal wall surface.   
     
     
         13 . The bolt member of  claim 10 , comprising:
 said shaft portion of said ejector member having a longitudinal center-line; and   said ejector head having a longitudinal center-line being co-extensive with said longitudinal center-line of said shaft portion of said ejector member.   
     
     
         14 . The bolt member of  claim 10 , comprising:
 said shaft portion of said ejector member defining an elongate lateral recess having forward and rearward recess end surfaces;   an ejector retainer member extending through said bolt body and having a portion thereof positioned within said elongate lateral recess; and   said stop surface of said ejector head being disposed for contact with said stop shoulder of said ejector pocket to limit propellant pressure responsive rearward linear movement of said ejector member and protect said ejector retainer member from impact damage by said forward recess end surface.   
     
     
         15 . The bolt member of  claim 14 , comprising:
 said ejector retainer member being a retainer pin of circular cross-sectional configuration and defined external surface curvature; and   said rearward end surface of said lateral recess of said shaft portion of said ejector member having an internal curvature matching said defined external curvature of said retainer pin and providing for surface to surface engagement with said retainer pin for optimum force transmission therewith.   
     
     
         16 . The bolt member of  claim 10 , comprising:
 said ejector head and said shaft portion of said ejector member being of integral one-piece construction;   said ejector head having a generally planar forward surface having a non-circular configuration being defined by oppositely facing end surfaces and oppositely facing side surfaces; and   said ejector head and said shaft portion of said ejector member having a common longitudinal center-line.   
     
     
         17 . The bolt member of  claim 10 , comprising:
 said bolt body defining a longitudinal center-line;   a longitudinal firing pin passage located substantially centrally of said bolt body along said longitudinal center-line and having a passage opening intersecting said generally planar bolt face surface; and   said ejector bore having a longitudinal bore center-line having substantially parallel relation with said longitudinal center-line of said bolt body.   
     
     
         18 . The bolt member of  claim 17 , comprising:
 said shaft portion of said ejector member defining an elongate lateral recess having forward and rearward recess end surfaces;   an ejector retainer member extending through said bolt body and having a portion thereof positioned within said elongate lateral recess; and   said stop surface of said ejector head being disposed for contact with said stop shoulder of said ejector pocket to limit propellant pressure responsive rearward linear movement of said ejector member and protect said ejector retainer member from impact damage by said forward recess end surface.