Pneumatic-hydraulic drive for tool

摘要

The drive brings the tool (5) rapidly into contact with the workpiece using a first pneumatic drive (2) and a pressure sensor (6) in the tool holder. At the same time a hydraulic proportional valve (17) feeds low pressure hydraulic fluid into the expanding hydraulic chamber (8). When the tool is in contact with the workpiece the first pneumatic drive is switched off and a second pneumatic drive (11) and the hydraulic drive provide a higher tool pressure with a slower movement for precise control. At the end of the tool process the procedure is reversed with the first pneumatic drive rapidly retracting the tool and with the hydraulic proportional valve equalising the hydraulic flow.