| 摘要 |
446,714. Screws and screwdrivers. PHILLIPS SCREW CO., Vancouver National Bank Building, 6th Street, Vancouver, Washington, U.S.A. July 3, 1935, No. 19053. Convention date, July 3, 1934. [Class 61 (iii)] [See also Group XXV] A screwdriver for screws provided with a non-circular inwardly tapering socket and having a number of concave flutes providing a number of tapering vanes engaging the grooves of the correspondingly formed screw socket has the taper of the screwdriver end relative to the axis different from the taper of the screw socket to enable it to wedge therein for holding the screw on the screwdriver. The vanes 8 of the screwdriver are formed by the converging walls 4, 7 of the flutes and the lines B, Fig. 5, represent the meeting lines of angularly disposed surfaces along the centres of the flutes. These lines B on the driver correspond with the lines of intersection 12 of the surfaces 11 of the walls of the screw socket but are at a steeper angle to the screw axis than the lines 12 so as to firmly grip thereon at the points C, the oblique ends 9 of the vanes being slightly out of contact with the bottom walls 15 of the grooves 13 in the screw. Screwdriver bits with two, three and five vanes and correspondingly socketed screws are also described. Specifications 427,892, and 427,893, [Group XXV], are referred to. |
