In one exemplary embodiment of the present invention, a gearbox assembly for a medical assist device having a motor assembly and a leg support is provided. The gearbox assembly includes a worm configured to be operably coupled to the motor assembly, and a worm gear meshingly engaged with the worm. The worm gear is configured to be operably coupled to the leg support, and the worm and the worm gear are configured to transfer rotary motion from the motor assembly to the leg support upon initiation of a force applied to the leg support.