Patent ID: 8453633

Claim:
A spring-piston airsoft gun comprising: a barrel extending along a stroke axis to terminate at a muzzle end and a gun-rear end, and defining an accommodation chamber which includes a front sub-chamber and a rear sub-chamber respectively proximate to said muzzle end and said gun-rear end; a cylinder disposed in said front sub-chamber, and having a front end that is in fluid communication with said muzzle end, and an inner tubular wall surface that extends rearwardly from said front end along the stroke axis; a piston member which includes a piston head configured to be fittingly received in said cylinder and in slidable contact with said inner tubular wall surface such that, when driven forward, said piston head forces air through said muzzle end to make a shooting action, and a tubular wall which extends rearwardly from said piston head along the stroke axis; a front anchor stem disposed in said tubular wall, and extending from said piston head along the stroke axis; a rear anchor shank unit which includes a core shank which is disposed in said rear sub-chamber, and which extends forwardly from said gun-rear end along the stroke axis to terminate at a positioned end region, a major shell which is sleeved on said core shank proximate to said gun-rear end, and a first minor ring which is sleeved on said core shank, which is in frictional contact with and angularly moveable relative to said major shell, and which is proximate to said positioned end region; and a coil spring disposed in said accommodation chamber to exert a biasing action to drive said piston head to force air through said muzzle end when said coil spring changes from a compressed state to a released state, and including a front coil segment which is secured to said front anchor stem, and a rear coil segment which extends rearwardly from said front coil segment, and which is configured to be sleeved on said first minor ring and said major shell such that, when said coil spring is released to expand to the released state, said rear coil segment is tensed to drag said first minor ring to move therewith angularly and, by virtue of the angular moveability of said first minor ring, a frictional force between said rear coil segment and said first minor ring is minimized, thereby enhancing the wearability of said first minor ring.