| 摘要 |
862,541. Screwdrivers. BREUNING, R. June 3, 1957 [June 1, 1956], No. 17518/57. Class 61. [Also in Group XXII] A double-ended screwdriver or a screw-and, nut driver comprises a shank 21 rotatable in a housing 20 having screw-threads for mounting the tool on a screw-threaded boss 14 in alignment with a screw 7 to be driven. Graduations 24 on the shank co-operate with a Vernier scale on the housing 20 to enable the screw to be driven a pre-determined distance. Stops 22, 23 on the shank limit its axial movement in the housing, and lugs 25, on the hollow end of the shank opposite the end formed with a screwdriving shoulder 21a engage the driving slots in a screw or a nut. |
