| 摘要 |
A device for restraining a truck from movement during the loading and unloading thereof while the truck is parked in a driveway in a loading dock. The truck restraining device has a lock assembly comprising a base and a locking arm pivotally mounted to the base for rotating between retracted and extended positions. In the retracted position, the locking arm is substantially horizontal for permitting the truck to drive over the restraining means whereas, in the extended position, the locking arm extends upwardly for engaging the truck wheels for restraining movement of the truck. The locking arm has a front end adapted to pivotally mount to the base and a rear end adapted to engage the wheel in the extended position. Means is provided for rotating the locking arm between the retracted and the extended positions. Means is provided for positioning the lock assembly between a distal and proximal positions and an intermediate position disposed between the distal and proximal positions in which the look assembly engages the wheel. Means is provided for controlling the position of the lock assembly between the distal and proximal positions in a programmed manner. The controlling means can: (1) automatically position the lock assembly at the distal position after the locking arm is rotated from the extended position to the retracted position; (2) automatically position the lock assembly at the distal position when the lock assembly reaches the proximal position; (3) automatically deactivate the positioning means when the lock assembly is immobile; (4) automatically deactivate a synchronous motor after the current or the torque of the motor reaches a predetermined value, and (5) automatically position locking arm tight to wheel for various wheel sizes.
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