Method and device for controlling a double-acting cylinder actuated by a pressurized fluid

摘要

PCT No. PCT/BE94/00079 Sec. 371 Date Apr. 25, 1996 Sec. 102(e) Date Apr. 25, 1996 PCT Filed Oct. 28, 1994 PCT Pub. No. WO95/11777 PCT Pub. Date May 4, 1995Method for controlling a pressurized fluid-actuated double acting cylinder in an assembly such as a hydraulic tightening spanner (1) with a control unit therefor, wherein a piston (5) may be reciprocated repeatedly, firstly with an active stroke providing a desired maximum force, and then with an opposed passive stroke returning the piston (5) to its starting point to enable repetition, and wherein said method comprises selecting a set fluid pressure corresponding to the desired maximum force (Fr) and measuring the time elapsed (Te) between the beginning and the end of the passive return stroke to determine that the force has been achieved. A device for implementing the force is also disclosed.