Fluid pressure motor mechanism

Claim 1

A FLUID PRESSURE MOTOR MECHANISM COMPRISING A CASING HAVING A PAIR OF PRESSURE RESPONSIVE ELEMENTS AND A PAIR OF WALLS COOPERATING WITH SAID CASING AND SAID ELEMENTS TO FORM ALTERNATELY LOW PRESSURE AND HIGH PRESSURE CHAMBERS, SAID HIGH PRESSURE CHAMBERS COMMUNICATING WITH EACH OTHER AND SAID LOW PRESSURE CHAMBERS COMMUNICATING WITH EACH OTHER, ONE OF SAID LOW PRESSURE CHAMBERS COMMUNICATING WITH A SOURCE OF LOW PRESSURE, A VALVE MECHANISM NORMALLY CONNECTING SAID HIGH PRESSURE CHAMBERS TO SAID LOW PRESSURE CHAMBERS AND MOVABLE TO CONNECT SAID HIGH PRESSURE CHAMBERS TO A SOURCE OF HIGHER PRESSURE TO ACTUATE SAID PRESSURE RESPONSIVE ELEMENTS, A NORMALLY STATIONARY AXIALLY MOVABLE UNIT CARRYING A PART OF SAID VALVE MECHANISM AND HAVING OPPOSITELY FACING PRESSURE SURFACES SUBJECT RESPECTIVELY TO PRESSURES IN SAID LOW PRESSURE SOURCE AND TO THE SAME PRESSURE AS SAID HIGH PRESSURE CHAMBERS TO HOLD SAID UNIT STATIONARY IN A NORMAL POSITION, SAID PRESSURE RESPONSIVE ELEMENTS BEING CONNECTED TO EACH OTHER AND HAVING A RADIALLY INNER RIGID MEMBER IN ABUTTING RELATIONSHIP WITH SAID UNIT, SAID VALVE MECHANISM INCLUDING A MANUALLY OPERABLE MEMBER HAVING LOST MOTION CONNECTION WITH SAID UNIT, WHEREBY, UPON A FAILURE OF SAID MECHANISM TO ESTABLISH DIFFERENTIAL PRESSURES IN SAID CHAMBERS, MOVEMENT OF SAID MANUALLY OPERABLE MEMBER WILL MOVE SAID UNIT TO ACTUATE SAID RIGID RADIALLY INNER MEMBER.