Patent ID: 6089931
Filing Date: 2000-07-18
Classification: B63H,F15B

Abstract:
A trim-tilt device interposed between a marine propulsion device and a boat body to which the propulsion device is tiltably attached, comprising:cylinder means adapted to receive fluid from and discharge fluid to a hydraulic fluid supply-discharge device to expand and retract for trim and tilt action of the propulsion device,said cylinder means comprising a cylinder connected to one of said boat body and said propulsion device;piston in said cylinder, anda piston rod attached to said piston and connected to the other of said boat body and said propulsion device,said piston defining in said cylinder a rod-side chamber and a piston-side chamber;a valve device on said piston for stopping the trim action by interconnecting said piston-side chamber and said rod-side chamber at an end of a trim region before a propeller of said propulsion device rises higher than the surface of the water when the propulsion device is generating a propulsive force;wherein said valve device comprises a relief valve which opens by a hydraulic pressure of said piston-side chamber during said trim action and which does not open by a hydraulic pressure of said piston-side chamber during said tilt action and a pilot valve which opens at said end of said trim region where said propeller of said marine propulsion device does not rise upward higher than the surface of the water, said relief valve and said pilot valve being arranged in series.