The chain wheel and the ratchet wheel are rotated together through the spline hole, and the chain wheel and the ratchet wheel are pulled into one by the hand. In this way, the lifting sprocket installed on the spline hole gear drives the lifting chain, so as to lift the weight smoothly. The ratchet friction plate one-way brake is adopted, which can brake automatically under load. The pawl engages with the ratchet under the action of spring, and the brake works safely.