| 摘要 |
PURPOSE: A structure and a driving method of an arm roll unit using a pin and a slot are provided to reduce the number of hydraulic cylinders in comparison to the arm roll unit of a conventional arm roll truck and to reduce the maintenance cost and the oil cost by decreasing the weight of a vehicle and the number of parts for driving the hydraulic cylinder. CONSTITUTION: The horizontal movement of an arm roll hook is made by the extending of a hydraulic cylinder through a pin mounted on the arm roll hook of an arm roll unit and a slot mounted on the arm roll unit. In order that the arm roll hook can rotate through the continuous extending of the hydraulic cylinder after driving, a pin mounted on the arm roll hook are inserted into a cylindrical bearing with an inner slot and then the rotating center is maintained while the arm roll hook rotates. The driving method of an arm roll unit is as follows. The arm roll hook rotates in an anticlockwise direction through the constriction of the hydraulic cylinder so that the arm roll hook returns to an original position after driving. When a slot, which is formed on the bearing to make a horizontal movement toward the front of a vehicle, and other slot, which is formed on the arm roll unit, maintain level, the pin, which has been inserted into the bearing, is separated. The arm roll hook returns to the original position through the horizontal movement through the continuous constriction of the hydraulic cylinder after being inserted into the arm roll unit.
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