Patent ID: 7595601
Filing Date: 2009-09-29
Classification: B25B,Y10S

Abstract:
1. An electric bolt/nut fastener, comprising: an inner socket which is engaged with a chip at a front end of a bolt; an outer socket which is engaged with a nut screwed to the bolt; a motor which is connected to both the sockets via a reduction mechanism which is capable of applying a rotating force in directions such that both the sockets are rotated oppositely; and a controller which controls the rotation of the motor, wherein the controller has a first rise detecting unit which detects a rush current as an abrupt rise in a current value of the motor at the time when a starting switch is turned ON, and a first fall detecting unit which detects abrupt fall and convergence of the current value immediately after the first rise detecting unit detects the abrupt rise in the current value, and the controller determines that, when the first fall detecting unit detects the abrupt fall and the convergence of the current value, rising of the rush current is ended, and discriminates the abrupt rise in the current value at the time when the starting switch is turned ON from a rise in the current value at the time of bolt/nut fastening to be generated later.