Abstract: In a boosted hydro-pneumatic drive for rapid traverse and power stroke, particularly for driving punching tools, a cylinder housing (1, 4) with partition (12), a disc piston (7) with plunger (8), a working piston (2) which can be loaded with compressed air for the return stroke and an annular piston (9) surrounding the plunger (8) are provided. The cylinder spaces between the working piston (2) and the annular piston (9) on both sides of the partition (12) are filled with hydraulic oil.In order to reduce the consumption of compressed air and to increase the speed of response, and for the purpose of simplification, the working piston (2) is provided with an annular surface (16a) which can be loaded with compressed air in the direction of advance, and a compression spring (10) is clamped between the disc piston (7) and the annular piston (9). The space accommodating the compression spring (10) is in constant connection with the outside air, preferably via a filter (11).

Abstract: The invention relates to a pneumo-hydraulic booster with rapid-traverse feature, particularly for driving punching tools, with a working piston which executes a rapid-traverse positioning stroke, a power stroke and a return stroke, with at least one further piston, and with chambers which adjoin these pistons and which, according to a program can be connected to a source of compressed air, in which arrangement a first chamber is pressurized during the positioning stroke and the power stroke, a second chamber is pressurized only during the power stroke and a third chamber is pressurized only during the return stroke and all chambers are vented at other times.