Importance

Loading Importance Indicators...

Abstract

A traction device for causing stepwise relative displacement between the device and an elongate member in the form of a cable (6) comprises a stationary clamp (5) and a movable clamp (3) which is displaced by a cylinder and piston unit (1, 2). Both clamps (3, 5) are self-closing, but are provided with pressure-operated opening devices (8, 9). The opening devices (8, 9) are controlled by a first control valve (12) which is changed over at the stroke ends of the piston (2) by dogs (13, 14). A second control valve (15) which controls the travel direction of the piston (2) is governed by the pressure medium fed to the opening devices (8, 9). To lift a load suspended from the cable (6), the piston (2) is raised, with the movable clamp (3) closed to grip the cable and the stationary clamp (5) open. At the top of the piston stroke, the stationary clamp (5) closes, the movable clamp (3) opens, and the piston (2) falls to enable the movable clamp (3) to grip the cable (6) again at a lower position.

Loading the Abstract Image...

First Claim