PLATE & FILM GP 1400113 - Caterpillar

Illustration 1 g03414536
Offset Hydraulic System "ZERO OFFSET"
(1) Check valve
(2) Counterbalance valve
(3) Steering cylinder
(4) Shuttle valve
(5) Steering control valve
(6) Compensator spool
(7) To side cutter
(8) From side cutter
(9) Steering pump
(10) Warm-up valve
(11) Steering shunt valve
(12) Steering manifold
(13) Margin spool
(14) Main relief valve
(15) Shuttle valve
(16) Shuttle valve
(17) Compensator spool
(18) Offset control valve
(19) Offset cylinder
(20) Shuttle valve
(21) Counterbalance valve
(22) Check valve The drum offset system and the steering system are both controlled by components contained within steering manifold (12). The steering system is controlled by steering control valve (5). The drum offset system uses the steering control valve and offset control valve (18) to control the drum offset while maintaining a constant steering angle. The drum offset system and steering system operate independently. Note: The following discussion of the drum offset system assumes that the machine is not steering. Refer to "Steering System" for additional information about the components and controls of the steering system.When the engine is running, steering pump (9) sends flow to port "P" of steering manifold (12). Supply oil passes through a filter and is directed to warm-up valve (10), margin spool (13), and compensator spools (6) and (17). If differential pressure across the filter exceeds 700 kPa (102 psi), a bypass check valve opens.When steering shunt valve (11) is energized, the steering system and drum offset system are enabled. When the shunt valve closes, all supply oil is directed to compensator spools (6) and (17) and warm-up valve (10). When the parking brake is applied, the steering system and the drum offset system are disabled. In this condition, the shunt valve is de-energized and directs all oil flow to the hydraulic tank.Margin spool (13) is a load-sensing valve. This spool compares the steering manifold (12) supply pressure with the highest pressure demand being placed on the steering system and the drum offset system. When the operator is not steering the machine or operating the drum offset system, steering control valve (5) and offset control valve (18) are de-energized. In this case, the demand pressure is at hydraulic tank pressure. Under these conditions, the margin spool shifts and directs the supply oil to the hydraulic tank.If steering cylinder (3) or offset cylinder (19) experience a shock load, the check valve in the low-pressure side of the affected cylinder opens. This action allows oil to enter the low-pressure side of the hydraulic cylinder, preventing cylinder cavitation. Counterbalance valves (2) and (21) limit the maximum pressure in the cylinders to 20000 kPa (2900 psi).Main relief valve (14) limits the maximum pressure in the steering system and the drum offset system to 20000 1000 kPa (2900 145 psi).
Illustration 2 g03414537
Offset Hydraulic System "RIGHT OFFSET"
(1) Check valve
(2) Counterbalance valve
(3) Steering cylinder
(4) Shuttle valve
(5) Steering control valve
(6) Compensator spool
(7) To side cutter
(8) From side cutter
(9) Steering pump
(10) Warm-up valve
(11) Steering shunt valve
(12) Steering manifold
(13) Margin spool
(14) Main relief valve
(15) Shuttle valve
(16) Shuttle valve
(17) Compensator spool
(18) Offset control valve
(19) Offset cylinder
(20) Shuttle valve
(21) Counterbalance valve
(22) Check valve When either drum offset switch is depressed,