BOLT FASTENER WITH INSPECTION FUNCTION

摘要

PROBLEM TO BE SOLVED: To allow a bolt fastener itself to determine whether or not bolt fastening is sufficient. SOLUTION: The fastener, by which a nut subjected to primary fastening (temporary fastening) is firmly fastened through the drive of a motor, has a differentiating circuit for differentiating the driving current of the motor, a primary fastening torque detection circuit, and a nut fastening angle checking circuit. The primary fastening torque detection circuit and the nut fastening angle checking circuit compare variation in a differential value of the differentiating circuit with initial experimental data to calculate the amount of primary fastening torque and the rotational angle of the nut so as to determine whether or not bolt fastening is sufficient.