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| Illustration 1 | g06389363 |
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(A) Hydraulic circuit for the jaw
(B) Hydraulic circuit for rotation (1) Speed control valve (2) Test fitting (3) Cylinder (4) Test fitting (5) Swivel (6) Crossover relief valve (7) Check valve (8) Relief valve (9) Gerotor motor | |
The hydraulic system for the Shear is divided into two separate circuits. One circuit is used to rotate the work tool, and the other circuit is used to operate the jaw.
- The hydraulic circuit for the operation of the jaw (A)
The hydraulic circuit for the jaw contains the following components: the main pumps (not shown), swivel (5), cylinder (3) and speed control valve (1).
- The hydraulic circuit for the rotation of the work tool (B)
The hydraulic circuit for rotation contains the following components: Crossover relief valve (6) and gerotor motors (9).
Cylinder (3) is a double acting cylinder that operates the jaw. This function of the work tool operates independently of the rotation hydraulic system. The cylinder operates at a maximum pressure of
Swivel (5) is mounted to the center of the rotator assembly. The swivel provides the necessary transfer of hydraulic oil from the input lines of the work tool to the hydraulic cylinder. The swivel allows the work tool to rotate 360 degrees.
When hydraulic oil is supplied to the head end of the cylinder, the rod is extended out of the cylinder. This causes the jaw of the work tool to close. When hydraulic oil is supplied to the rod end of the cylinder, the rod retracts into the cylinder. This causes the jaw of the work tool to open.
Speed control valve (1) is used to decrease the time that is necessary to close the jaw. The valve diverts displaced oil from the rod end of the cylinder to the head end of the cylinder. The increase in flow speeds up the extension of the cylinder. As a result, the jaw closes faster. Refer to Service Manual, "Speed Control Valve" for further information.
Crossover relief valve (6) is designed to relieve pressure in the section of the hydraulic system that operates the gerotor motors (9). Two relief valves make up the relief for the crossover. The relief valves protect each side of the motor circuit from excessive pressure.
The pressure setting of each relief valve is
When one of the relief valves open, pressure is dumped to the opposite side of the rotate circuit. This design prevents damage to the work tool from an external rotational force.