Arrangement for braking movement of cylinder unit piston - involves valve unit with first and second positions for input of pressure medium under low and high resistance

摘要

The cylinder unit (1) has a piston (3) dividing the cylinder (2) into a first chamber (5) connectable to a pressure medium source (9) for moving the piston from first to second end positions, and a second chamber (6) which contains pressure medium and is connected to a valve unit (14). The valve unit has first and second positions which during the movement of the piston produce movement of pressure medium from the second chamber (6) under low and high resistance respectively. A signal indicator (17) monitors the piston position so that when the latter reaches a point between the two end positions it passes a signal to the valve unit which then changes from its first to its second position in order to brake the piston movement. The valve unit in its second position conducts pressure medium from the second chamber to a closed gas chamber (13) in which a counter pressure is built up to gradually increase braking force.