Patent ID: 8997628
Filing Date: 2015-04-07
Classification: F01B,G01D

Abstract:
1. In combination, a hydraulic actuator for a marine craft, and a position sensor and limit switch apparatus therefor, the hydraulic actuator having a trim cylinder and a piston with at least one magnetized portion reciprocatingly disposed within the trim cylinder, said at least one magnetized portion of the piston comprising an annular magnet, the annular magnet having an aperture with a tapered wall extending therefrom, the piston including a central member extending through the annular magnet, the central member being ferromagnetic, and the piston further including a spacer interposed between the magnet and the central member, the spacer having a radially extending tapered wall, the magnet being positioned in a set orientation with respect to its poles when the tapered wall of the spacer abuts with the tapered wall of the magnet, the apparatus comprising: an elongate housing aligned parallel with the cylinder; a magnetostrictive linear displacement transducer disposed within the housing for sensing the position of said at least one magnetized portion; and a limit switch which operatively interrupts actuation of the piston upon said at least one magnetized portion reaching a trim-out limit position, said limit switch being responsive to the transducer, the trim-out limit position being a maximum extended position of the piston considered safe to operate the marine craft under power.