US Patent 7350286 Rotational and axial power transmitting apparatus

Threaded member assembling can be performed using a rotational/axial-movement-transmitting unit including an upper frame; a motor held by the upper frame; a female threaded member secured to the upper frame; a male threaded member assembled in the female threaded member, the male threaded member having a rotational/axial-movement-transmitting end at one end, and having a driven rotary end at the other end; and a joint member connecting an output terminal of the motor to the driven rotary end for transmitting rotation torque from the output terminal to the driven rotary end and for allowing axial movement of the male threaded member relative to the motor.