Hydraulic system for aircraft landing gear and hydraulic actuator therefor

Claim 1

A HYDRAULIC ACTUATOR COMPRISING A HOUSING HAVING A CYLINDRICAL BORE, A PISTON MOVABLE IN SAID BORE FOR A GIVEN AXIAL STROKE AND DIVIDING SAID BORE INTO FIRST AND SECOND WORKING CHAMBERS, A PISTON ROD CONNECTED WITH SAID PISTON AND EXTENDING THROUGH ONE END OF SAID HOUSING, MEANS IN SAID HOUSING DEFINING FIRST AND SECOND PORTS COMMUNICATING RESPECTIVELY WITH SAID FIRST AND SECOND WORKING CHAMBERS FOR SUPPLYING AND EXHAUSTING WORKING FLUID TO AND FROM SAID CHAMBERS, MEANS IN SAID HOUSING DEFINING A THIRD PORT ADAPTED FOR CONNECTION WITH AN AUXILIARY FLUID ACTUATED DEVICE, MEANS DEFINING A FLOW PATH PROVIDING COMMUNICATION BETWEEN ONLY SAID FIRST AND THIRD PORTS, AND VALVE MEANS IN SAID FLOW PATH FOR CONTROLLING THE FLOW OF WORKING FLUID BETWEEN SAID FIRST AND THIRD PORTS IN ACCORDANCE WITH THE POSITION OF SAID PISTON RELATIVE TO SAID HOUSING BORE AND IN SUCH A MANNER THAT SAID FLOW PATH IS CLOSED WHEN SAID PISTON IS AT ONE LIMIT OF ITS STROKE AND OPEN WHEN AT THE OTHER LIMIT OF ITS STROKE WHEREBY SAID THIRD PORT IS PLACED IN OPEN COMMUNICATION WITH SAID FIRST PORT WHEN SAID PISTON IS AT SAID OTHER LIMIT OF ITS STROKE AND IS BLOCKED FROM COMMUNICATION WITH BOTH SAID FIRST AND SECOND PORTS WHEN SAID PISTON IS AT SAID ONE LIMIT OF ITS STROKE.