Linear actuator without piston shaft - has bellows between central piston and end plates and piston sliding along rod

摘要

The linear actuator has no piston rod but the piston (12) slides along a fixed rod (10) between two end plates (15,16). Pressure chambers (22,23) are formed between the piston (12) and end plates (15,16) by expanding bellows (19,20). Air is introduced into the chambers (22,23) through channels (17,18) machined into the end plates. The bellows (19,20) are reinforced by spirally wound steel wire (21) and are of general conical form. A block (13) fixed to the piston periphery is attached to the workpiece. In a variant only one bellows is used, with spring action return.