| 摘要 |
908,124. Screwing-up and unscrewing screws etc.; drilling. PLASSER, F., and THEURER, J. Feb. 18, 1959, No. 5643/59. Addition to 846,936. Class 83 (3). A machine for screwing-up and unscrewing screws or nuts according to the parent Specification has a modified drive by which the wrench 4 may be given a slow, powerless rotation to facilitate its engagement with a nut. The wrench-motor 2 is supplied through a line 5 by a pump 8. During idle rotation of the wrench, a branch line 9 returns some of the pressure liquid to a tank 1, through a spring- opened control-valve 10 and an adjustable bleed-valve 11. Valve 10 is connected by a rope or cable 13 to a pivoted handle 17 on the handle H of a wheel-borne chassis (not shown). Pivotal movement of handle 17, against the action of a spring-pressed plunger 16, tends to slacken cable 13 and allow the spring 12 to close valve 10. Thus, the full pressure of the pump-liquid passes to motor 2. A preferably adjustable relief valve 7 in a branch line 6 controls the maximum torque applied by the wrench, which may be replaced by a drill. |
