GB1101331A - A traction or lifting appliance - Google Patents

Abstract

1,101,331. Cable grips. OFFICE CENTRAL DE GESTION ET DE CONTROLE O.G.E.C. 2 Feb., 1965 [4 Feb., 1964; 12 Jan., 1965], No. 4418/65. Heading F2X. A traction or lifting appliance having two pairs of self-closing jaws 1, 2 and an hydraulic jack, Fig. 5, for displacing one pair relatively to the other, has one pair of jaws connected with the piston rod of the jack and the second pair of jaws arranged adjacent the end of the jack remote from the movable pair. The jaws carry semi-cylindrical lateral trunnions, such as 7, 7 4 (Fig. 4), mounted in levers, such as 3, having their pivots mounted in external cheek members of the jaws and are biased into the closed position by a compression spring in a sheath 9 or 9 1 . In a further embodiment, the means for displacing one pair of jaws relatively to the other consists of twin jacks 18, 18 1 , Fig. 5, having a common base 11 with anchoring lugs 13 and a boss 14 to secure the fixed pair of jaws and a coupling bar 19 to connect the jack piston to the external cheek members of the movable pair of jaws 2 which is reciprocably mounted on guide rods 21 and 21 1 . A telescopic device 24, 25 and 26 guides the cable between the fixed and movable pairs of jaws while a rod mechanism 31 enables the levers of the jaw pairs to be temporarily coupled when the jaws are to be opened simultaneously for introduction or removal of the cable. In a second construction, the pairs of jaws are connected to separate pistons in a common jack cylinder while in a third construction a hollow piston-rod is provided for passage of the cable. A fourth embodiment uses a single ram and a parallel pair of telescopic link mechanisms, one of which is connected directly between the jaw actuating levers while the other is connected to these levers through an arrangement of spring- loaded bell-crank levers and abutments so that the jaws of each pair are opened alternately as the movable pair of jaws reciprocates. In a fifth embodiment, Fig. 9, the ram has a partition 63 dividing it into two coaxial cylinders, each of which contains a piston 70, 67 to actuate the jaws of each pair while a third piston 64 reciprocates the movable pair of jaws, the fixed pair being connected to the ram which is mounted on wheels and carries a valve block. A pilot valve 96 carried at one end of the ram cylinder is actuated by the movable pair of jaws to control a distributing valve to reverse the movement of the piston 64 and to actuate the pistons for controlling the jaws. A second distributer permits the direction of travel of the cable to be reversed and connects a pilot-controlled valve between the spaces at opposite sides of the piston 64 to limit the rate of travel. The circuit also includes valves to provide slight excess thrust to the right on the piston 70 to bias the stationary jaws to the closed position and a valve to provide a constant pressure drop from chamber A to chamber B when the ram contracts and is driven by the load.