Abstract: A screw threaded insert to be installed in for example thermoplastic material by ultrasonic vibrations applied to the insert is double-ended and comprises a main helically ribbed portion separated from a minor portion formed with teeth or projections aligned with helical ribs, and a pilot portion. The pilot portion is to locate the insert in a performed bore in the required orientation of insertion, the toothed portion displaces material in complementary grooves, so as to facilitate travel of the insert into the material and ensure good filling of the inter-rib spaces.

Abstract: A screw threaded insert to be installed in for example thermoplastic material by ultrasonic vibrations applied to the insert is double-ended and comprises a main helically ribbed portion separated from a minor portion formed with teeth or projections aligned with helical ribs, and a pilot portion. The pilot portion is to locate the insert in a performed bore in the required orientation of insertion, the toothed portion displaces material in complementary grooves, so as to facilitate travel of the insert into the material and ensure good filling of the inter-rib spaces.