Patent GB-1199228-A (GB)
Title: Device for Compensating Automatically for Variations in the Tension on and Length of Cables in Appliances for Transferring Loads Between Two Relatively Movable Objects by Cables
IPC: B66C7/00
Filed: 1968-05-22
Abstract: 1,199,228. Cable tensioning apparatus. SOC. DES FORGES ET ATELIERS DU CREUSOT. 22 May, 1968 [1 June, 1967; 6 July, 1967; 7 Dec., 1967], No. 24482/68. Heading B8B. A device for automatically compensating for variations in tension and length of cables C 1 , C 2 , C 3  facilitating the transferring of a load P between two relatively moving objects A, B (e.g. ships), comprises cable winders disposed on one ship A and each winder compensating for variations in the length of one of the cables these winders being interconnected and subjected to the action of a constant force which tensions the cables. In the embodiment shown, the winders comprise pulleys 6, 8 mounted on yokes 7 to which weights M 1 , M 2  are secured forming the tensioning force. The yoke 7 with the weight M 1  is used when the load P approaches or leaves the ship B, the weight M 2  being locked to a guide M 2 , and the weight M 2  is used while the weight M 1  is locked to its guide M 1  when the load P is approaching or leaving the ship A. The load supporting carriage 1 runs along the cable C 1  under the control of opposing cables C 2 , C 3  which are payed out and wound in at equal rates by respective winches U 2  and U 3  the tension in all three cables being maintained constant and the variation in distances between the two ships being compensated for, by whichever weight M 1 , M 2  is not locked to its guide. With the load P stationary adjacent the ship B, winches U 1 , U 2 , U 3  for the cables C 1 , C  2 ,C 3  are stationary and relative movement of the ships is compensated for, without the load moving relative to ship B, by all three cables paying out equally from the ship A as the weight M 1  is lifted. When the load P is to remain stationary relative to the ship A, the three winches are stationary and only two cables C 1 , are payed out as the weight M 2  is lifted. cable C 3  being payed out at twice the speed of cable C 1  since the cable C 2  fixes the position of the load relative to the ship A. In the embodiments of Figs. 5-6 (not shown) the weights are replaced by either compressive or tensile spring, pneumatic or oleopneumatic devices. In the embodiment of Figs. 9 the winders comprise differential gear units Q 2 , Q 3  connecting the winding drums of the cables C 2 , C 3  to the winding drum of the cable C 1  which latter drum is driven by a constant torque motor F 1 , for cable-tension maintenance. Clutches, P 2 , P 3 , P 4  gearing and a brake F 2  are provided between the differential units and the drum for the cable C 1  such that either all three cables may be payed out and wound in equally, or the cable C 3  may be payed out at twice the speed of cable C 1  while the drum for the cable C 2  is stationary, depending on the position of the load relative to the ship. In the embodiment of Figs. 12, 13, 14 (not shown) auxiliary tensioners are associated with the transferring cables (C 2 , C 3 ) to compensate for variations in the length and tension therein due to the variable sag and loading caused by the load (P) as it moves from ship to ship. The embodiment of Figs. 15, 16, 17 (not shown) incorporates a repeater for indicating the positions and movements of the load between the two ships. The repeater comprises calibrated discs gear driven by the cable winches such that the instantaneous distance between the ships and the instantaneous position of the load relative to the ships is either visually indicated or transmitted by pulse detectors to an operation control regulator. In the embodiment of Fig. 18 (not shown) the winches of the transferring cables (C 2 , C 3 ) are each linked to a differential unit which are both linked to a common differential unit driven by the control torque winch motor for the carrier cable (C 1 ). A clutch and brake placed between the common differential unit and the unit of the cable (C 2 ) are alternately operated depending upon which ship is being approached or left by the load carriage, whereby the variations in cable length between the ships are allowed for by the appropriate pair of differential units. In the embodiment of Figs. 19 and 20 (not shown) the upper transferring cable (C 3 ) is used to support the load carriage and the carrier cable (C 1 ) is dispensed with.