GEARBOX-DRIVE 4776273 - Caterpillar

Illustration 1 g01004959
(1) Pressure adjustment screw (2) Passage to hydraulic tank (3) Spring (4) Spring (5) Pilot valve (6) Spring (7) Cavity (8) Relief valve (9) Passage to hydraulic tank (10) Orifice (11) Pump oil passageThe elevator relief valve for the elevator circuit is located in the elevator control valve. The elevator relief valve is pilot operated.Oil from pump oil passage (11) flows through orifice (10) into cavity (7). Spring (4) and spring (6) keep relief valve (8) on the seat. When the pump oil pressure in passage (11) increases to the pressure setting of the relief valve, pilot valve (5) opens. The oil in the cavity (7) flows out of the passage (2) to the hydraulic tank. The oil pressure in passage (11) is now higher than the oil pressure in cavity (7). The oil pressure will open relief valve (8) against the force of spring (4) and spring (6). Pump oil will flow past the relief valve (8) through passage (9) back to the hydraulic tank.The setting of the relief valve can be adjusted with pressure adjustment screw (1). Turn the adjustment screw clockwise in order to increase the pressure setting. Turn the adjustment screw counterclockwise in order to reduce the pressure setting.