Patent ID: 8468911

Claim:
A feed apparatus which moves a movable body with respect to a stationary body in a moving direction having a vertical component, and which has a ball screw disposed in such a manner that a ball screw axis extends in the moving direction and is rotatable about the ball screw axis, a nut threadably engaging the ball screw, a drive motor for rotating the ball screw about the ball screw axis, and control means for controlling the operation of the drive motor, one of the ball screw and the nut being disposed on the movable body, the other being disposed on the stationary body, the control means being configured to, after stopping the movement of the movable body, cause the drive motor to maintain the movable body at the stop position, wherein: the feed apparatus further has braking means for braking movement of the movable body, and the control means is configured to: when recognizing a movement command for rapid traverse relating to the movable body, on the basis of a target position according to the movement command for rapid traverse and the current position of the movable body, check whether the movable body is to be moved upward from the current position thereof or is to be moved downward from the current position thereof; when judging that the movable body is to be moved upward, move the movable body upward past the target position, and then reverse the moving direction of the movable body and move the moving body to the target position, and on the other hand, when judging that the movable body is to be moved downward, move the movable body directly to the target position; and after moving the movable body to the target position, cause the drive motor to keep the position of the movable body at the stop position and cause the braking means to brake the movement of the movable body.