A machine for screwing and then of bolts or pulls - bottoms

摘要

The rail track bolt tightening and release machine has an internal combustion engine (13) mounted on a frame that runs along the tracks. The engine drives two hydraulic pumps (14,15) delivering different flow rates. The hydraulic pumps drive the tool that tightens or releases the bolts. Solenoid valves (19,20) control delivery from the two pumps so that in one mode their outputs are combined and in the other only the output of a single pump is used. A microcomputer (24) is used to control operation of the unit. The microcomputer program (26) has stored a table converting pressure to torque. An electronic pressure transducer (23) delivers pressure information to the microcomputer, which controls the solenoid valves to produce the required torque.