Patent ID: 8056276

Claim:
A backlash vibration structure for a toy gun having a trigger and a transmission mechanism for firing a toy riffle which is received in a rear side of a lower receiver in axial alignment with a piston in a piston-cylinder mechanism having a piston spring, wherein said backlash vibration structure comprises: a receiver extension adapted for being connected to said rear side of said lower receiver; a reaction spring received in said receiver extension; a buttcap spacer coupled at a rear side of said receiver extension; a weight disposed at said receiver extension at a position that said reaction spring is positioned between said weight and said buttcap spacer, wherein said weight has a front tip extended to said lower receiver for coupling with a rear end of said piston spring, wherein during an operation of said toy gun, said weight is forced backward to compress said reaction spring, wherein when over a compression limit of said reaction spring, said reaction spring forces said weight forwards to produce a backlash vibration; and an adjustable knob operatively coupled with said buttcap spacer and arranged to adjust a spring force of said reaction spring so as to selectively adjust a level of said backlash vibration, wherein when said adjustable knob is moved forward relative to said buttcap spacer, said spring force of said reaction spring is increased for increasing the level of said backlash vibration, when said adjustable knob is moved backward relative to said buttcap spacer, said spring force of said reaction spring is decreased for reducing the level of said backlash vibration.