Patent attributes
An anti-disengagement structure of a tool head for insertion into an insertion recess of a fastener is provided. Abutting faces extend from a periphery of an end face of a working portion. At least one abutting face is partly formed with a groove filled with an elastic member which is partly protrusive out of the groove and beyond the surface of the abutting face. The largest extent between the protruded-out part of the elastic member and the abutting face of another elastic member is larger then the largest inner extent of the insertion recess. Thereby, with the stretchable characteristic of the elastic member, the fastener can be smoothly inserted into the insertion recess and abutted against an inner surface of the insertion recess to achieve anti-disengagement effect.