| 摘要 |
<p>An apparatus for positioning a tool and/or clamping a work piece; the apparatus comprises a working arm (10) angularly rotatable between a plurality of opening positions (A) and a closed position (B) against a work piece. A linear pneumatic actuator (14) is operatively connected to the working arm (10) by means of a toggle-lever drive device (13); the pneumatic actuator (14) comprises a single piston (26) connected to the toggle-lever device (13) by means of a threadingly extensible piston rod (18), which is adjustable in length to change the opening angle of the working arm (10). A drive member (36) operatable from the outside is selectively engagable with the piston rod (18) to adjust its axial length.</p> |
