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.

Abstract: A valve base for establishing connections to valves in hydraulic circuits comprises a base having in it a number of coplanar longitudinal channels, groups of holes each in a standardized pattern to fit a standardized pattern of connections of a hydraulic valve, and a transverse bore associated with each group of holes and intersecting all the longitudinal channels. Each transverse bore contains a column of distributor modules held by terminal members at the ends of the bore. The distributor modules are of different types of hollow cylinder and are separated by discs which may be solid or annular so as to block or permit flow along the bore. A module may have one or two lateral openings, or a circumferential groove in its external surface, to provide a choice of connections.A valve of cartridge type may be incorporated as a module, either fitting directly in the bore or with an adaptor, or may be incorporated in a terminal member.