(57) A control valve (1) for an hydraulic piston-cylinder assembly (28) having one port
(10) connected to the cylinder (27) and another port (11) connectable into a circuit
which controls relative movement between the cylinder (27) and piston (30). The two
ports (10, 11) communicate through the body (2) of the valve (1) and a closure member
(4) is movable between positions at which it opens ans closes that communication.
A striker (21) associated with the piston-cylinder assembly (28) and responsive to
relative movement thereof in one direction, is engagable with an abutment (22) of
the closure member (4) so as to move that member (4) towards the valve closed position.
As the closure member (4) approaches the closed position, a throttling portion (19)
of that member (4) becomes operative to restrict fluid flow between the valve ports
(10, 11) and thereby creates a pressure differential which acts across the closure
member (4) to move that member (4) free of the influence of the striker (21) and into
the closed position. When the throttling portion (19) is inoperative, fluid pressure
within the valve (1) tends to urge the closure member (4) towards the open position.
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