Apparatus for restraining movement of a parked vehicle away from a loading dock comprises an upwardly extending block which is movable from a lower position to an upper position which captures a portion of the parked vehicle to restrain movement of the parked vehicle away from the loading dock. This apparatus provides a safety lock system to ensure that during loading and unloading of a parked vehicle the vehicle cannot accidentally pull away from the loading dock which would result in injury to the forklift truck operator. A linkage mechanism is provided which provides for the raising and lowering of the block. A drive mechanism raises and lowers the linkage in determining the lower an upper positions of the block. The linkage comprises two spaced-apart linked arms which may be in the form of a parallelogram linkage arrangement.
