GB1186244A - Double-Acting Hydraulic Cable Pulling System. - Google Patents

Abstract

1,186,244. Fluid pressure apparatus acting through ropes. TRACTEL S.A. 14 Nov., 1967 [14 Nov., 1966; 16 Nov., 1966; 12 April, 1967; 13 April, 1967], No. 51657/67. Heading B8B. [Also in Division Fl] An hydraulic cable traction apparatus coinprises two double acting hydraulic actuators 7, 8 in series and through the piston rods 3, 4 and cylinders of which the cable extends, and self-clamping cable clamps 1, 2 on the ends of the rods 3, 4, the two chambers 9, 11 and 10, 12 of both actuators being connected to a common hydraulic circuit which controls in synchronism, the movements in opposite directions of the piston rods and the automatic reversal of their strokes. While the clamp 2 in the unclamped position slides to the right (in the Figure) along the cable, the clamp 1 clamps the cable and hauls it to the left until a spring return distributer 37 is actuated by the clamp 1 whereby monitor pressure lines 34, 35 are coupled and a distributer 31 is reversed. This latter operation couples the pressure supply line 32 through a non-return valve, to the chamber 12 of actuator 8 instead of to the chamber 11 of actuator 7. However, with the circuit shown in the Figure the chamber 11 is fed from the line 32 and the piston 5 moves to the left whereby fluid in the chamber 9 is transferred via a line 13 to the chamber 10 of the actuator 8, the piston 6 thereof moving to the right while the chamber 12 is discharged through a spring returned exhaust valve 18. The latter is opened by pressure in a monitor line 22 which is coupled through a spring returned distributer 24 to a monitor line 14 in communication with the line 13. The distributer 24 is opened by pressure in a monitor line 30 in communication -with the supply line to the chamber 11. An exhaust valve 19 for the chamber 11 is closed by exhausting its monitor line 21 through a distributer 23 which is in its spring returned position since its monitor line 29 is coupled into the line exhausting the chamber 12. The embodiment of Fig. 2 (not shown) comprises an auxiliary hydraulic actuator associated with each first said actuator and having its piston rod linked to the associated clamp whereby the opening of the clamps is hydraulically controlled and the apparatus can be used for steadying the " paying out " of the cable. In the embodiment of Fig. 3 (not shown) continuous traction of the cable is achieved by closing the clamp to be closed before opening the clamp to be opened, the non-hauling stroke of the appropriate piston assembly taking less time than the hauling stroke of the other piston assembly. In the embodiment of Fig. 4 (not shown) for paying out cable, hydro-pneumatic accumulators in the hydraulic circuit are used to store energy during unclamped piston strokes of the actuators, and to give it up (during the clamped strokes whereby an external source of fluid pressure supply is not required.