Patent ID: 6880446

Claim:
An air cushion cylinder apparatus with a lock, the apparatus comprising a cylinder and a pneumatic circuit for supplying compressed air to the cylinder, wherein the cylinder includes a piston, a piston rod, first and second pressure chambers on opposite sides of the piston, first and second ports for supplying compressed air to the pressure chambers, an air cushion mechanism for restricting a flow rate of exhaust discharged from the respective pressure chambers to thereby stop the piston at stroke ends in a cushioned manner, and a lock mechanism for locking the piston rod at a stop position, the lock mechanism has a lock member for operating by an action of air pressure, a third pressure chamber for causing air pressure to act on the lock member, and a third port for supplying compressed air to the third pressure chamber and is formed such that the lock member unlocks the piston rod when compressed air is supplied into the third pressure chamber from the third port and that the lock member locks the piston rod when compressed air in the third pressure chamber is discharged from the third port, the pneumatic circuit includes a solenoid valve for opening and closing a flow path connecting the cylinder and a compressed air source, speed controllers each formed by connecting a check valve and a throttle valve in parallel are respectively connected in first and second pipes connecting the solenoid valve and the first and second ports, and a speed controller formed by connecting a check valve and a throttle valve in parallel is connected in a third pipe connecting the third port and the first pipe or the second pipe.