GB620037A - Improvements relating to control units for hydraulic systems - Google Patents

Abstract

620,037. Manually-actuated valves. JENNINGS, H. W. K. (Electrol, Inc.). Dec. 13, 1945, No. 33811. [Class 135] [Also in Group XXXIII] A control unit for hydraulic double-acting jacks comprises a lever actuating a plunger 19, Fig. 5, having cam surfaces which co-operate with a series of valves 27, 27a, 28, 28a, so that when the plunger is moved longitudinally into one position by its operating lever, two valves are opened by the cam surfaces to connect pressure and exhaust to opposite ends of the jack, when the plunger is moved into its other longitudinal position, the previously mentioned valves are closed and the other two are opened to reverse the flow to the jack, and when the plunger is rotated by a further lever, the pressure inlet is disconnected from the jack and both sides of the latter are connected to exhaust. Pressure liquid and exhaust are connected to chambers 30, 29, respectively, and the two ends of the jack are connected to ports 27b, 28b. When the plunger is in its upper position, valves 27, 28a are opened and the other two are closed, and the connections are reversed when the plunger is lowered. As applied to the control of the wing flaps and the landing gear on an aeroplane, two separate sets of control valves, each with its associated plunger, are arranged side by side in a single casing 5, Fig. 2, and the actuating levers 12, which have a pin-and-slot connection 21 with the plungers 19, project from the front panel of the casing. The levers 12 are interconnected by a tooth clutch 49 so that, normally, the two levers act together, but when the wing flap lever is in its lower position, a pin-and-cam slot arrangement causes the clutch to disengage and the landing gear lever can be actuated independently. At other times, the clutch can be positively disengaged by pressing sideways on an arm 56 carried in a slot in the wing flap actuating lever. There is a lever and slot connection between the landing gear lever and an emergency pull rod 14 whereby, when the latter is pulled out, an intermediate lever carried thereby rotates the appropriate plunger 19 and the cam surfaces thereon open both exhaust valves and allow the inlet valves to close. A separate lever, not shown, frees the lock usually provided on the landing gear lever when in its " lowered " position.