GB985536A - Tool for installing a wire coil screw thread insert - Google Patents

Abstract

985,536. Screwing-up wire coil helices. HELI-COIL CORPORATION. June 29, 1962 [Oct. 16, 1961], No. 25005/62. Heading B3N. A tool for inserting a wire helix 17 in a tapped hole comprises a body 10 with an interiorly threaded foot portion 12 and nut portion 21, a charging chamber 16 and a mandrel 11 having a screw thread 24 on the front end thereof to receive the insert 17 with the tang 26 of the latter engaging a slot 25 in the front face, and a screw thread 28 to engage the nut portion 21. The thread 24 has a diameter approximately equal to that of the inner screw thread forming portion of the insert 17 when contracted by the foot portion 12. The front end of the mandrel can be projected out of the foot, a nut 30 carried on a thread 29 acting as an adjustable stop. The mandrel end is so formed that the insert tang 26 can readily enter the slot 25 and be turned by the mandrel when the latter is rotated in one direction and that the mandrel can be disengaged and freely withdrawn from the tang upon rotation in the opposite direction. The interior body threads 13, 21 of the lead-in nut and foot respectively and the threads 24, 28 of the mandrel are of equal pitch. The threads of the lead-in nut and foot are in phase whereas the two threads of the mandrel are one half pitch out of phase. In a modification, Fig. 5 (not shown), the actual nut thread is formed by an insert of the same type as that to be installed, the threads of the foot and nut being out of phase by one half pitch whereas the two mandrel threads are in phase relatively to each other. In another modification the mandrel is provided with a continuous thread. Specifications 590,363 and 985,537 are referred to.