GB1224041A - Improvements in or relating to hydraulically-actuated devices - Google Patents

Abstract

1,224,041. Winch brakes. LANGDALE ENG. CO. Ltd. 27 May, 1969 [30 May, 1968], No. 25919/68. Heading B8B. [Also in Division F2] The shaft 2 of an hydraulically operated reversible winch drum 31 is movable from a position in which the drum is braked to one in which the drum is unbraked, by an hydraulic piston-and-cylinder device which is actuated in the same direction in response to pressurized fluid driving the drum motor in either direction. The drum shaft 2 is eccentrically mounted in lever arms 3, an extension 7 of one of which is rotatably acted upon by the hydraulic device against the resistance of a spring return arrangement 13, 14, 15. The hydraulic device comprises a cylinder 20 housing a lower piston 22 and an upper piston 21 spring biased apart, a ram 19 on the piston 21 extending from the cylinder to receive a push-rod 12 engageable with the extension 7. A port 26 in the cylinder wall at the lower end thereof and a port 27 between the two pistons, are coupled to the two hydraulic lines controlling the winch motor and pressure is supplied to one port or the other depending on the direction of rotation of the drum, whereupon either the two pistons are biased apart and the rod 12 moves the arm 3 to release the drum brake, or the piston 22 is raised to compress the spring 24 and move the piston to move the arm 3. A port 49 is provided at the top of the cylinder wall to facilitate a double action of the device, but is normally connected to exhaust. The hydraulic circuit includes a manual valve to selectively couple two winch drums in parallel, and a counterbalance valve between the motor supply and return lines. Each winch brake comprises a pair of brake drums on the winch drum and engageable with brake shoes secured to the winch mounting structure.