GB253509A - Screw threading dies and holders therefor - Google Patents

Abstract

253,509. Bruno, R. June 13, 1925, [Convention date]. Void [Published under Sect. 91 of the Acts]. Screwing dies and dieheads; stocks and dies.- A divided screwing-die is used in a hinged stock and may be adapted for either hand or machine use. A circular die is divided into two or four segments 5, Fig. 7, which are retained in pockets of the hinged arms 77, 78 by screws 57. Spigots may be provided in the pockets to co-operato with axially aligned holes in the dies, or projections may be provided on the inner circular surfaces of the pockets. A spring located in recesses 80 of the arms tends to open the dies and a lug 85 on one arm passes through the forked end of the other to serve as guiding means. When used in a machine the pivot 79 of the hinge slides in a stationary bearing 88 and the free ends of the arms are guided between blocks 93, 94 which may be fixed or adjustable by a screw 95. After a predetermined length of thread has been cut the arms spring open against stops 96, 97, and for taper threading the blocks are given a diverging contour. As applied to a die-stock, the part 103, Fig. 11, carries handles 104 and has hinged thereto the part 105 adjusted by a nut 106 and a spring 107. In a modified form of holder which is suitable for hand or machine use the dies are mounted in a spring ring 100, Fig. 9, adjusted by a screw 102 and provided with external ribs or indentations. Each die may be composed of external discs, or several hinged stocks may be coupled together, the first discs having roughing teeth while the remainder finish and gauge the thread. Alternatively, each disc may cut its own thread.