Model HL25 Instruction and Parts Manual
The PULLMASTER Model HL25 is a planetary, hydraulic winch with two forward speeds and one reverse speed. At low forward or hoisting speed this unit has a line pull capacity of 25,000 lb on the first layer of wire. In the “rapid forward” mode the line pull capacity is reduced by a ratio of 4.67 and the line speed increases by the same ratio. The change from low speed to rapid forward speed is actuated hydraulically and can be made while the drum is rotating. The main components of this unit are:
- Hydraulic motor
- Multi-disc brake with static and dynamic function
- High speed clutch
- Primary planet reduction
- Final planet reduction
- Brake housing
- Final drive housing
- Cable drum
FUNCTION IN FORWARD ROTATION:
LOW FORWARD SPEED
During low forward speed the output torque and rpm of the hydraulic motor is transmitted by the motor drive shaft to the primary sungear of the primary drive. The output torque and rpm of the primary drive is transmitted to the final drive by the final sungear, which is splined to the primary planet hub. The output torque and rpm of the final drive is transmitted to the cable drum by a spline, attaching the final planet hub to the cable drum. The motor drive shaft is splined to a clutch hub which connects to a set of friction and divider plates. During low speed operation, a pressure plate, which is “spring applied” and “pressure released”, permits free rotation of the friction plates.
The motor drive shaft is also attached to a connecting shaft by a sprag clutch which permits free rotation of the motor drive shaft while the connecting shaft is stationary. The connecting shaft is held stationary by another sprag clutch to a brake hub. During low forward speed operation, the automatic brake remains applied, hence, the brake hub, the connecting shaft and the internal gear do not rotate.
RAPID FORWARD SPEED
When rapid forward speed is actuated, hydraulic pressure is channelled from the motor to the center bore of the motor drive shaft to the clutch piston. The hydraulic pressure causes the clutch to engage against the clutch springs. The clutch hub is splined to the motor drive shaft and the drive gear is splined to the connecting shaft, the internal gear of the primary drive will rotate with the motor drive shaft. Thus, the planetary drive is eliminated.
The elimination of the primary drive results in a forward or hoisting line speed 4.67 times faster than low forward speed. The line pull capacity during “rapid forward” operation must be decreased by a ratio of 4.67. When the pressure is removed from the clutch, the clutch is disengaged by the clutch springs and the unit reverts to low forward speed. Since the sprag clutch, which connects the connecting shaft to the brake hub, permits free rotation, the automatic brake of the winch is not affected during rapid forward speed.
NOTE:
The change over from low forward speed to rapid forward speed can be made while the drum is rotating, providing the load on the wire rope does not exceed 5357 lb (23.8 kN) on the first layer of wire rope. If this load is exceeded, winch will stall.
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