GB850304A - Improvements relating to water-tight door and like door systems - Google Patents

Abstract

850,304. Hydraulic control systems. STONE & CO. (CHARLTON) Ltd., J. Dec. 31, 1958 [Jan. 20, 1958], No. 1930/58. Addition to 811,020. Class 69 (2). [Also in Group XXV] An hydraulically-controlled door system comprises a differential piston 2 which is connected to a door D and on one face is subjected to a constant pressure and on the other face to pressure or exhaust by means of a local control device 9 and by a master control device 8 exercising its control through hydraulic operating means 35 acting, in addition to manual operating means 29, upon the local control device, the manual operating means being movable by the hydraulic operating means to a position in which the local control device is set for the door-closing condition, and being movable, by manual actuation only, to a further position in which the local control device is still in the door-closing condition, but the manual operating means is engaged automatically by a detent device 41 holding it there until the detent device is disengaged by local intervention. The face 6 of the piston 2 is connected to an exhaust line 12 or to a line 11, which constantly supplies fluid pressure to the face 4 of the piston, by movement of the manual operating means 29 which is in the form of a lever, opening one or other of valves 27, 28 in the device 9. The master control device 8 also connects the face 6 to the lines 11 or 12 by rotation of cams 18, 19 opening one or other of valves 14, 15. When the device 8 is in the door-closing position, valve 14 is open and the pressure in line 11 is supplied to a line 10 leading to the lower face of a differential piston 35 which moves upwardly to rock the lever 29 to the door-closed position and open valve 27 to connect pressure line 11 to the face 6 of the piston to close the door. The local control device 9 may be retained in this position, irrespective of further operation of the master control device 8, by further manual movement of the lever, permitted by a lost-motion connection 34, 44, to a position wherein the spring- pressed detent 41 engages a hole 42 in a fixture 43 ; the detent must be disengaged before the door can be opened by the master control device 8. The lost-motion connection also permits the lever 29 to move the local control device to the door-closed position when the master control device is in the door-open position. When the door is closed by the master control device, the door can only be opened by the local control device while the lever 29 is held upwardly and the piston 35 held down against the fluid pressure. A manually-operated pump 20 can be operated from a position remote from the door in the event of a failure of the main pumping plant and may be connected by a valve 23 to the pressure line 11a and to a chamber 46 which, when supplied with fluid pressure, moves a plunger downwardly to engage an extension on the lever 29 which is thus moved to the door-closed position to actuate the local control device. A further manually operated pump 21, positioned local to the door, may be used for both opening and closing the door, the lever 29 being used in the normal manner.