Patent GB-674123-A (GB)
Title: Hydraulic controlling device for the lifting winches of the trawls on board fishing boats
IPC: A01K73/06
Filed: 1949-08-04
Abstract: 674,123. Hydraulic transmission of power; liquid-pressure engines. SOC. ANON. DES ANCIENS CHANTIERS DUBIGEON, and GUINARD, P. A. Aug. 4, 1949 [Sept. 10, 1948], No. 20305/49. Class 69 (ii). In apparatus for lifting fishing trawls comprising an internal-combustion engine 2, Fig. 1, a winch 9 and a hydraulic transmission between the engine 2 and the winch 9, the transmission including a pump 1 and a hydraulic motor 5 fed thereby and either of the transmission elements having a constant volumetric capacity and the other a variable capacity, there is provided a hydraulic valve 4 serving as a torque-limiting device for the hydraulic motor. The constant-delivery rotary cylinder pump 1, which is driven by the engine 2 through gearing 3, is connected by pipes 6, 7 to the reversible, variable-output rotary cylinder motor 5, that drives the winch 9 through a flexible coupling 9a. An auxiliary pump 10 draws liquid from a reservoir 11 and so compensates for any leakage in the system, whilst another reservoir 14 associated with a valve 13 provides for temperature compensation of the liquid ; the main circuit is of the closed type. The bye-pass valve 4, integral with the pump 1, comprises a spring-loaded valve 18, Fig. 2, with an attached piston 19, which valve in the open position directly connects pipes 6 and 7 ; the liquid for operating the valve is taken from pressure pipe 6 and passes through passage 16 where it actuates a spring-loaded slide valve 22. When the pressure in pipe 6 reaches a predetermined value it moves valves 22 far enough leftwardly to permit liquid to reach piston 19 by means of a channel 25 and so wholly or partially open valve 18 and place the pressure and exhaust pipes 6 and 7 in communication. The valve 22 may also be moved leftwardly by a spring-loaded piston 29 supplied with liquid from pipe 6 under the control of a manual valve 27. The motor consists of a rotor 34, Fig. 3, carrying two pairs of opposed pistons at right angles which reciprocate in cylinders 37, 38 and 39, 40 ; each pair of pistons being freely mounted on a fixed shaft 47 by means of slots ; the eccentricity of the shaft 47 with regard to the rotor shaft 35 is adjustable by a hand wheel 54 through gearing 55, 56, 57 and a crank mechanism to vary the stroke and speed of the motor. Valve casing 58 secured to the top of the motor stator 36 has slidable therein a hollow valve 63 operated from the wheel 54 by an endless screw 65. The valve 63 can either permit free flow between the motor inlet port 59 and outlet port 60 or completely or partially close either one of these ports to permit of reversal of rotation and a gradual start in either direction of rotation. The speed of the motor may be automatically varied in accordance with variations in driving torque by means of an auxiliary motor which adjusts the eccentricity of the main motor ; the auxiliary motor is under the control of a spring-loaded differential piston valve. The outer end of the smaller piston part is connected to pipe 7 whilst the opposed annular surfaces of the piston valve are connected to pipe 6.