(57) The pressure fluid actuator (10) comprises a tubular body (11) and closing heads
(12,13) to define a piston chamber (14) in which a piston (15) may reciprocate. The
piston (15), at both ends, is provided with a damping bush (25) which may protrude
into a flow damping chamber (18,19) in each closing head (12,13) connected to a fluid
inlet/outlet port (16,17); a conduit (25A) comprising a flow throttling valve (23)
is branched between each side of the piston chamber (14) and the damping chamber (18,19)
in each closing head (12,13). The flow damping bush (25) comprises a longitudinally
extending fluid supply duct (32) provided with a pressure actuated unidirectional
flow control valve (30,32) which prevent the pressure fluid to flow from the piston
chamber (14) into the damping chamber (18,19) during damping at the end of a piston
stroke, while allowing flow circulation into the piston chamber (14) when the bush
(25) is within the damping chamber (18,19) at the beginning of a piston stroke.
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