Long object handling machine - has gripper actuated by piston-cylinder unit whose control valve includes blocking and non-return spool

摘要

The pick-up has a load gripper actuated by a piston cylinder unit the latter being controlled by a valve assembly including a blocking spool and a nonreturn valve (3L). The blocking spool is coupled to a pilot element via a pilot line, the pressure fluid supply to the valve itself being via the non-return valve. This blocking spool pref. includes a stepped piston the latter controlling the supply of pressurised fluid to the chamber of the piston-cylinder unit. The non-return valve can include a plunger which is spring biased into the closed position.