Hydraulic tilt and trim control for marine propulsion

摘要

A hydraulic arrangement for controlling the tilt and trim of an outboard drive. The hydraulic arrangement comprises a single cylinder assembly having a single bore inside wherein two separate pistons are supported for reciprocation and sealed to the cylinder with piston seals. The lower piston is connected to a valve mechanism that selectively opens or closes a cylinder relief hole depending upon the position of the piston within the cylinder. The valve mechanism operates so that the piston seals never contact the relief hole to prevent premature failure of the piston seals.