GB918265A - A screw - Google Patents

Abstract

918,265. Making screws. TELEFONAKTIEBOLAGET L. M. ERICSSON. Nov. 11, 1960 [Nov. 11, 1959], No. 38913/60. Class 83 (2). [Also in Group XXV] A screw is formed by twisting a parallelsided, flat strip 1, e.g. of brass, about its longitudinal axis so that the axis remains straight and the edges 2 form helices, these edges being formed with a screw-thread coaxial with the helices and of a pitch smaller than that of the helices. An untwisted end portion 3 of the strip may provide the means for turning the screw and may have a hole which may contain a pin, Figs. 3, 4 (not shown). For turning by hand or by a flattened tube, it may bear a pressed-on cap 4 with a flange 5 for bearing on the workpiece. It may be bent to one side, Fig. 6 (not shown), or divided and bent to both sides, Fig. 5. A solid cheese-head may be pressed on to it, Fig. 7 (not shown), or it may be larger than the rest of the strip and formed with downward extensions 14, Fig. 10, which are curved each to one side. These extensions 14 may be directed in a clockwise direction on a left-hand screw, for example, so that sharp edges 15 precede the roots of the extensions when unscrewing, so that such action is impeded. The strip may be twisted for its whole length, Fig. 8, a cap being pressed or screwed on its end. The cap may be a plain open cylinder, Fig. 9 (not shown), in which case the screw is turned by the fingers or a tool with a slot for receiving the strip end or the cap may be formed with a screwdriver slot 12 and a flange 5. A number of open caps which may each have a flange may be spaced along a continuous strip and pressed or rolled on before the strip is cut in screw lengths.