Abstract: A bypass valve is disclosed which relieves pressure on the end cap and rod guide of a cylinder as the piston approaches them. The bypass valve has a cylindrical body with end caps on each end, the end caps serving as stop members. The bypass valve is provided with longitudinal grooves along the cylinder body, along which working fluid can pass through a bore in the piston in which the bypass valve is inserted. Inner smaller diameter counterbores and outer larger diameter counterbores are provided coaxially with the bore on the opposing faces of the piston. The end caps of the bypass valve are received in the counterbores when the piston is urged along the cylinder. When the piston approaches either the rod guide or the end cap, the bypass valve is urged away from its seated position when an end cap of the bypass valve touches the approached rod guide or end cap of the cylinder.

Abstract: A relief valve for a hydraulic piston consists of a tubular mid-section with closed ends and circular stops at each end. The tubular center section has cross ports at each end that run perpendicularly to the axis of the valve. The cross parts are situated as close to the end stops as possible. The cross ports intersect the hollow center of the spool and allow hydraulic oil to flow through the piston via the passageway in the center of the valve when the valve is in the open position.