| 摘要 |
985,537. Screwing-up wire-coil helices. HELI-COIL CORPORATION. June 29, 1962 [Oct. 16, 1961], No. 25006/62. Heading B3N. A power-driven tool for installing a wire-coil insert in a tapped hole comprises a tubular housing 10, a rotatable drive sleeve 17, a hollow prewinder body 16 releasably connected to the housing 10 and including an interiorly threaded prewinder foot 34, a nut portion 38 of the same pitch as the thread of the foot 34 and a charging chamber 37, a mandrel 35 being axially shiftable in the sleeve 17 and projectable with its slotted front end through the foot 34. The mandrel has a head 24 permanently connected to the driving sleeve for common rotation and has an external screw thread 30 at its driving end to receive an insert, the mandrel being helically guided in the nut 38 throughout its movement. The threads of the nut 38 are one half pitch out of phase with the thread of the prewinder foot 34, so that the inner threadforming part of the insert passing through the prewinder foot is in lead with the thread of the nut. The housing 10 and sleeve 17 which is journalled in a needle bearing 18 are connected respectively to the stator and rotor of a reversible prime mover e.g. an air motor which automatically stops rotation when a predetermined load is exceeded. A rubber bumper 27 is located on the drive shaft 19 between the coupling element 21 and the mandrel head 24. An interchangeable spacer ring 44 on the shank of the mandrel limits the distance the mandrel can project. The thread of the nut portion 38 is formed by an insert 40 of the type to be inserted in a workpiece by the aid of the tool. The slot 32 at the end of the mandrel 23 extends part way across the end face 31 which has an apex providing slopes permitting the mandrel to become disengaged from the insert after installation, on return movement of the mandrel. Specification 985,536 is referred to. |
