Firearm trigger mechanism
A trigger mechanism that can be used in AR-pattern firearms has a hammer, a trigger member, a disconnector, a locking member, and a “three position” safety selector having safe, standard semi-automatic, and forced reset semi-automatic positions. In the standard semi-automatic position, rearward movement of the bolt carrier causes rearward pivoting of the hammer such that the disconnector hook catches the hammer hook, at which time a user must manually release the trigger member to free the hammer from the disconnector to permit the hammer and trigger member to pivot to the set positions so that the user can pull the trigger member to fire the firearm. In the forced reset semi-automatic position, rearward movement of the bolt carrier causes rearward pivoting of the hammer causing the trigger member to be forced to the set position, the safety selector preventing the disconnector hook from catching the hammer hook, and thereafter when the bolt carrier reaches the substantially in-battery position the user can pull the trigger member to fire the firearm without manually releasing the trigger member. The locking member is pivotable between a first position at which the locking member mechanically blocks the trigger member from moving to the released position and a second position at which the locking member does not mechanically block the trigger member allowing the trigger member to be moved to the released position. The locking member is spring biased toward the first position and moved against the spring bias to the second position by contact from the bolt carrier during forward movement of the bolt carrier as the bolt carrier reaches a substantially in-battery position.
1. A firearm trigger mechanism comprising:
a hammer having a sear catch and a hook and adapted to be mounted in a fire control mechanism pocket of a receiver to pivot on a transverse hammer pivot axis between set and released positions, said hammer adapted to be pivoted rearward by rearward movement of a bolt carrier,
a trigger member having a sear and adapted to be mounted in the fire control mechanism pocket to pivot on a transverse trigger member pivot axis between set and released positions, said trigger member having a surface positioned to be contacted by a surface of said hammer during rearward pivoting of said hammer to cause said trigger member to be forced to said set position,
wherein said sear and sear catch are in engagement in said set positions of said hammer and trigger member and are out of engagement in said released positions of said hammer and trigger member,
a disconnector having a hook for engaging said hammer hook and adapted to be mounted in the fire control mechanism pocket to pivot on a transverse disconnector pivot axis,
a locking member adapted to be movably mounted in the fire control mechanism pocket, said locking member being movable between a first position at which said locking member mechanically blocks said trigger member from moving to said released position and a second position at which said locking member does not mechanically block said trigger member allowing said trigger member to be moved to said released position, said locking member spring biased toward said first position and adapted to be moved against said spring bias to said second position by contact from the bolt carrier during forward movement of the bolt carrier as the bolt carrier reaches a substantially in-battery position, and
a safety selector adapted to be movably mounted in the fire control mechanism pocket to move between safe, standard semi-automatic, and forced reset semi-automatic positions,
whereupon in said standard semi-automatic position, rearward movement of the bolt carrier causes rearward pivoting of said hammer such that said disconnector hook catches said hammer hook, at which time a user must manually release said trigger member to free said hammer from said disconnector to permit said hammer and trigger member to pivot to said set positions so that the user can pull said trigger member to fire the firearm, and
whereupon in said forced reset semi-automatic position, rearward movement of the bolt carrier causes rearward pivoting of said hammer causing said trigger member to be forced to said set position, said safety selector preventing said disconnector hook from catching said hammer hook, and thereafter when the bolt carrier reaches the substantially in-battery position the user can pull said trigger member to fire the firearm without manually releasing said trigger member.
2. The trigger mechanism of claim 1 , wherein said safety selector is configured such that, when said safety selector is in said forced reset semi-automatic position, said safety selector contacts said disconnector preventing said disconnector hook from catching said hammer hook.
3. The trigger mechanism of claim 1 , further comprising a spring which biases said trigger member towards said set position.
4. The trigger mechanism of claim 1 , wherein said trigger member pivot axis and said disconnector pivot axis are the same axis.
5. The trigger mechanism of claim 1 , wherein said safety selector is adapted to be pivotably mounted in the fire control mechanism pocket to pivot on a transverse safety selector pivot axis.
6. The trigger mechanism of claim 1 , wherein said locking member is adapted to be pivotably mounted in the fire control mechanism pocket to pivot on a transverse locking member pivot axis.
7. The trigger mechanism of claim 1 , further comprising a housing having a first pair of transversely aligned openings for receiving a hammer pivot pin and a second pair of transversely aligned openings for receiving a trigger member pivot pin.
8. The trigger mechanism of claim 7 , wherein said housing has a third pair of transversely aligned openings for receiving a locking member pivot pin or screw.