NOTCH FOR IMPROVED HOOK OF TONGUE-LESS SPIRAL COIL INSERTINGBODY

摘要

A helically coiled wire insert of the type used for tapped holes in parent material that is generally softer than the bolt being screwed into the tapped hole, whereby the two free end coils have a hook recess on the inner screw thread of each and the terminal end of each free end coil has a reduced transverse cross section along one longitudinal axis of the wire. The surfaces of the hook recess are angled from the longitudinal axis of the insert to provide increased forces along the longitudinal axis of the insert.