| 摘要 |
411,359. Bolts; drive-screws. HOFFMANN MANUFACTURING CO., Ltd., New Street, Chelmsford.-(Assignees of Bott, G. R. ; 8, Howes Avenue, Stamford, Connecticut, U.S.A.) Oct. 21, 1933, No. 29222. Convention date, Aug. 2. [Classes 89 (i) and 89 (ii).] The two parts 15, 16 of a ball or roller bearing cage are secured together by self-tapping fasteners 18 which are forced into the material between the pockets for the antifriction elements in such a way as to cut their own threads in the material. The fasteners 18, Fig. 3, have hardened quick pitch threads reversely arranged at their two ends, and a reduced part 23 in the middle to allow for displaced material. The pilot ends 22 of these fasteners take into aligned threadless holes 21 drilled, punched, or moulded in the parts 15, 16. The latter may be of fibrous or resinous material such as " Micarta " or the material known by the Registered Trade Mark " Bakelite," or of metal such as bronze. Fastteners with intermediate spacer bodies thicker than the reversely threaded ends are used to unite thin cage rings in spaced relation. Other fasteners have continuous multiple threads, and, for uniting a thick and a thin cage ring, fastteners with heads fitting countersunk recesses in the thin ring are used. |
