| 摘要 |
1,131,423. Woodscrews. G.K.N. SCREWS & FASTENERS Ltd. 24 Jan., 1966 [2 Feb., 1965], No. 4401/65. Heading F2H. [Also in Division B3] A woodscrew comprises a shank formed of polygonal, e.g. square, section wire twisted about its longitudinal axis to provide a plurality of circumferentially spaced flutes 44 separated by corners 43 of the wire, and a woodscrew type thread 60 extending from the tip and having its crests of maximum radial depth at each corner where the overall thread diameter equals the outside diameter of the twisted wire before threading, and having its thread crests of minimum depth at positions corresponding to the maximum depth of the flutes, with the minimum depth of axially adjacent threads being staggered in a circumferential direction in consequence of the inclined disposition of the flutes. |
