초록 ▼

A vehicle convertible top is moved by hydraulic cylinders between extreme raised and lowered positions. The cylinder ends are connected to ports in a reversible hydraulic pump in one end of an elongated housing, which has a reservoir in the other end, separated by a pump cap. The pump cap houses two

A vehicle convertible top is moved by hydraulic cylinders between extreme raised and lowered positions. The cylinder ends are connected to ports in a reversible hydraulic pump in one end of an elongated housing, which has a reservoir in the other end, separated by a pump cap. The pump cap houses two fluid circuits connecting the pump to the ends of the cylinders. Each circuit has an end of cycle hydraulic locking device comprising a normally-closed valve and a valve actuator. The circuit valves are alternately opened by pump pressure to pressurize one end of the cylinders to alternately raise and lower the top. The opened valve closes when the pump ceases operation, preventing fluid backflow through the one circuit to the pump. This hydraulically locks the top in extreme raised and lowered positions to facilitate top latching and tonneau installation. A groove in the valve seat forms a leakage path which bypasses the closed valve to slowly reduce hydraulic pressure in the actuator at a predetermined rate until pressure is relieved after a predetermined period of time sufficient to accomplish top latching or tonneau installation. A manually-operated pump bypass in the pump cap vents both circuits to the reservoir to enable manual top operation when the pump is inoperative. The pump cap includes makeup valving for accommodating the displacement differential in the cylinder.

대표청구항 ▼

In a vehicle having a convertible top, a hydraulic actuator for moving the convertible top between extreme raised and lowered positions and having a pair of fluid translating ports, a hydraulic fluid reservoir, and a motor-operated reversible hydraulic pump connected to the reservoir during operatio

In a vehicle having a convertible top, a hydraulic actuator for moving the convertible top between extreme raised and lowered positions and having a pair of fluid translating ports, a hydraulic fluid reservoir, and a motor-operated reversible hydraulic pump connected to the reservoir during operation and having a first fluid translating circuit connected to an actuator port for driving the actuator to raise the top and a second fluid translating circuit connected to the other actuator port for driving the actuator to lower the top, an end of cycle locking device comprising a normally-closed first circuit valve in the first circuit that is opened by pressure fluid from the pump to enable outflow of pressure fluid to the actuator in the first circuit during pump operation in one direction, wherein the first circuit valve closes when the pump ceases operation, thus preventing the backflow of fluid through the first circuit to the pump which maintains sufficient hydraulic pressure to hydraulically lock the top in extreme raised position, a leakage bypass across the first circuit valve for permitting the controlled backflow of hydraulic fluid at a predetermined rate from the actuator to the pump to relieve actuator hydraulic pressure to unlock the top after a predetermined period of time, and a first valve actuator for the first circuit valve operable in response to pressure fluid in the second circuit during pump operation in the other direction to open the first circuit valve to enable the return flow of pressure fluid through the first circuit.