| 摘要 |
There is disclosed a pneumatic driving device having a cylindrical housing in which a piston element is axially displaceable. The piston element has at its ends a front piston and a rear piston which are connected to each other by a connecting pipe. A switch element is mounted in the housing between the pistons and defines a variable front chamber with the front piston and a variable rear chamber with the rear piston. Two inlet openings acted on by pressure are formed in the housing and can be connected with the front and rear chambers respectively. The switch element, in a first position, frees the inlet opening to the rear chamber so that the rear piston travels axially outward and the front piston axially inward and, in a second position, frees the inlet opening to the front chamber so that the front piston moves axially outward and the rear piston axially inward. The inwardly moving pistons reverse the switch element between the two positions.
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