Patent attributes
The present invention mainly aims to rebuilt the structures of a hook body, valve and control handle and the link relationship thereof. The outer surface of two shrouds of the control handle are respectively stamped with a depression adapted project a similar limit block out of the inner surface of each shroud, the limit block having upper, lower blocking surfaces opposite to each other vertically, and the upper, lower blocking surfaces are further controlled to be perpendicular to the shroud, thereby allowing them to transfer stably the stress between the hook body and valve when withstanding the stress due to the inadvertent opening of the valve so that the valve and limit blocks are not deformed easily, have a longer use and enhance the overall use safety greatly.
