Patent ID: 8226072
Filing Date: 2012-07-24
Classification: B25J,B66C,Y10T

Abstract:
1. A power assist apparatus comprising: a workpiece holding device that holds a workpiece; an arm that supports the workpiece holding device; a joint portion that connects the workpiece holding device to the arm to be rotatable in at least one direction; a brake mechanism that restricts rotation of the workpiece holding device in the at least one direction about the joint portion; a switch that is operated by an operator for switching the brake mechanism between a locked state, in which rotation of the workpiece holding device is restricted, and a released state, in which rotation of the workpiece holding device is allowed; an angle sensor that detects a rotation angle of the workpiece holding device in the at least one direction about the joint portion; and a controller configured to control the brake mechanism, when the operation of the switch by the operator for switching the brake mechanism from the released state to the locked state is detected, such that when the rotation angle detected by the angle sensor is greater than a predetermined lower limit and smaller than a predetermined upper limit, the controller switches the brake mechanism from the released state to the locked state, and such that when the rotation angle is less than or equal to the predetermined lower limit or is greater than or equal to the predetermined upper limit, the controller maintains the released state of the brake mechanism.