Safety plier automatic triggering mechanism for telescopic elevator mounting platform

A safety plier automatic triggering mechanism for a telescopic elevator mounting platform comprises a movable part, a fixed part, a spring, a transverse rod part and a triggering movable part; the fixed part is fixed to a portal frame upper beam of an elevator, the movable part is fixed to a hoister, the transverse rod part is fixed to the portal frame upper beam through a shaft part, and the twoends of the spring abut against the upper portion of the fixed part and the lower portion of the movable part; one end of the triggering movable part is hinged to the lower portion of the movable part, and the other end of the triggering movable part is fixed to the transverse rod part; the end part of the transverse rod part is connected with a pulling plate of a safety plier through a connectingpiece; and when elevator rapid weightlessness occurs, a spring pushes away the movable part to enable the movable part to be away from the fixed part, the movable part drives the triggering movable part to rotate around the t