Patent ID: 6405632
Filing Date: 2002-06-18
Classification: A01J,F15B

Abstract:
A protection device for controlling the motion of a pneumatic actuator (3), comprising at least one elongated cylinder (6) provided with a piston (4), dividing the cylinder (6) into a first chamber (5a) and a second chamber (5b), an actuating pressure supply line (14) connectable to at least one of said first and second chambers (5a, 5b), a control means (22) for controlling the motion of the piston (4) relatively to the cylinder (6), and a sensor means (23, 30) adapted to sense a piston feature related to the piston motion and being co-operating with the control means (22), said control means (22) limits the motion of said piston (4) as soon as signaling from said sensor means (22, 30) indicates that an excessive value of said piston motion has been established, characterized in that a valve means (20, 36, 28, 29) controlled by said control means (22), said valve means (20, 36, 28, 29) being connectable to said first and second chambers (5a, 5b), and adapted to open a connection between said first and second chambers (5a, 5b).