Patent ID: 8793988
Filing Date: 2014-08-05
Classification: B23Q,G01B,G05B

Abstract:
1. A positioning device comprising: a servo motor that drives a vertical axis; a controller that controls the servo motor; an air balance that cancels a self-weight of the vertical axis, the positioning device further comprising: an air supply source that supplies air to the air balance; a pressure regulating device that regulates pressure of the air balance using air supplied from the air supply source; and an air balance pressure modifying unit that modifies the pressure of the air balance and moves the vertical axis in a direction which enables avoiding a collision between a structure that moves with the vertical axis and another structure or reducing a collision therebetween, when an excitation of the servo motor is released due to an emergency stop, a power outage, or another operation performed on the positioning device; wherein the air balance pressure modifying unit generates a force that is equal to or greater than a thrust of the servo motor due to a pressure variation of the air balance.