| 摘要 |
A pneumatic actuator device comprises a first piston (18) movable in a first axial chamber (12) situated at the rear end thereof, a piston (20) movable in a second axial chamber (14) situated in front of said the first, a separation wall (28) between the two axial chambers through which there slides a hollow rod (24) inter-connecting the pistons (18, 20), and an advance member (40) connected to the pistons and situated at the front of the actuator body (10). Pressurized fluid feed means include a slide valve. The separation wall (28) has a transverse bore (72) in which the slide of the valve is received, a first duct (74, 76) which connects the transverse bore (72) to a pressurized fluid feed (66, 68), a second duct (82) which connects the transverse bore (72) to the rear portion of the second axial chamber (14), and a third duct (84) which connects the transverse bore (72) to the front portion of the first axial chamber (12). The first and second ducts (74, 76; 82) are in communication with each other and are isolated from the third duct (84) when the slide of the valve is in a first position, while the first and third ducts (74, 76; 84) are in communication with each other and isolated from the second duct (82) when the slide is in a second position.
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