Abstract: A safety lock device including a clover mechanism mounted on a rotating shaft to be used with an unbalanced free-fall dog that precludes rotation of the rotating shaft upon rapid acceleration or excessive speed of the rotation of the shaft. The free-fall dog is pivotally mounted on a fulcrum upon which the free-fall dog may teeter in an unbalanced seesaw motion. At opposite ends of the fulcrum are a locking finger and an arm. The free-fall dog is unbalanced such that the arm contacts the clover mechanism as it rotates while the locking finger does not contact the clover mechanism at slow rotating speed. At a slow rotative speed, the arm is only slightly deflected. With great acceleration, the arm is deflected farther from the clover mechanism thereby causing the locking finger on the opposite side of the fulcrum to be pivoted into the clover mechanism.