| 摘要 |
1,163,371. Screws. TORRINGTON CO. Ltd. 17 Feb., 1967 [21 Feb., 1966; 22 Dec., 1966], No. 7656/67. Heading F2H. A screw comprises a head 7 terminating in a bottom surface 10 adjacent a shank portion 8, and channels 14 extending radially from a central portion of the head, the channels each being defined by a pair of oppositely disposed walls 15, 16 and a bottom sloping surface 17 which slopes both in the radial and circumferential directions of the head 7. The channels may penetrate or stop short of the circumferential wall of the head and the head may be provided with a frusto-conical surface for countersinking purposes (Fig. 6, not shown).
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