Sensor which checks end of stroke of pneumatic jack - includes first channel connecting air inlet/outlet block with work chamber,these channels provided with first and second anti-return valve

摘要

The unit contains a primary channel (104) and a secondary channel (105) which joins a block containing the air inlet and discharge (2) to the jack (1). Each channel (104,105) contains a drain (119,118) forming a venturi connected to a single chamber (120) in which can slide a piston (121). When there is an air flow the venturi cause a depression which allows the piston (121) to be biased to the end of the chamber (120)by the spring (122). When the piston of the jack (1) reaches the end of its stroke, there is a pressure build up which moves the piston in the chamber (121). This movement is sensed by the detector (124,125) which delivers a signal to the controller of this effect. Use/Advantage - A sensing unit for informing the controller of the end of stroke of a piston in a pneumatic jack in a sequence operation which can be adjusted without reprogramming the controller and which signals the effect only after the air pressure is at its operating value.