Patent ID: 7273329
Filing Date: 2007-09-25
Classification: B63C

Abstract:
1. In a hydraulic boat lift having a submerged elongate base frame including adjustable vertical legs with adjustable feet, forward and aft cross beam members, transversely spaced longitudinal beams fixedly joining said cross beam members, swingable parallel elongate boat lifting frames pivotally mounted at their lower ends to the forward and aft ends of the longitudinal beams where they join the cross beam members, a boat cradle pivotably attached to said lifting frames at their upper ends, said boat cradle extending generally parallel to the base frame, such base frame, lifting frames and boat cradle forming an approximate parallelogram, hydraulic jack means extending generally diagonally of such parallelogram for swinging the lifting frames relative to the base frame so as to elevate the boat cradle and a boat resting thereon, said jack means comprising a cylinder assembly containing a piston assembly with a piston shaft provided with a plurality of spaced apart recesses, said piston shaft entering into said cylinder assembly, and a locking pawl which by gravity engages one said recess to prevent the piston shaft from retracting into the cylinder assembly when the boat cradle is elevated, the improvement comprising: said locking pawl being generally L-shaped, one leg thereof being pivotably mounted on said cylinder assembly adjacent said piston shaft and having an inner surface, said pawl being removable from an engaged recess on the piston shaft by directing water pressure upward through a conduit adjacent said piston shaft at the inner surface of said pivotably mounted leg.