Piston mechanism with a cylinder in which a power piston is displaceable back and forth, actuated by a pressurised fluid, which by means of a valve mechanism is alternately introducible into two pressure chambers, situated at either side of the piston

摘要

The invention relates to a piston mechanism comprising a cylinder 1 in which a power piston 2 is displaceable back and forth, actuated by a pressurised fluid. The movement of the power piston is controlled by a valve mechanism, which alternately applies the pressurised fluid into pressure chambers 11, 12 situated at opposite sides of the piston. According to the invention, the valve mechanism comprises a pilot slide 3 displaceable in the cylinder between two stops 6, 7. The pilot slide is further provided with channels 8, 9 connecting inlet and outlet chambers in the cylinder with either of the two pressure chambers situated on opposite sides of the piston, respectively. The power piston is further displaceable on the pilot slide between two limit positions in which the power piston abuts on second stops 4, 5, thereby displacing the pilot slide a distance which entails reversal of the directions of flow of the pressurised fluid. The piston slide is preferably arranged concentric in the power piston. In order to ease the reversal of the power piston at the end positions, spring elements 20, 21 are arranged on opposite sides of the power piston, adequately in the form of helical springs around the pilot slide. The invention may be utilised in a multitude of applications, e.g. for brushes with alternating directions of rotation. IMAGE