Hydraulic pushbutton sensor for e.g. press guard - has button with rounded head and cylindrical body which is slidable in sleeve to pilot valve spool

摘要

The hydraulic push-button (7) sensor may be used to detect the presence of a moving machine part (1). The button (7) is of round section and reciprocates axially between a projecting and a retracted position relative to a support body (4). The button now gives the authorization signal when retracted, e.g. when pressed home by a press guard (1). The button is permanently subjected to fluid entry pressure and is movable between two positions. The button may comprise a cylindrical piece (7, 9, 11) which slides in a sleeve (2) which is fixed in a blind hole (2). Both the button and the sleeve have radial shoulders delineating three sectors of different uniform dia.