ULTRASONIC BOLTING CONTROL APPARATUS

摘要

Apparatus (10) for measuring and controlling the tensile load on a fastener (F). The fastener is positioned to connect together two or more components (X) of a workpiece. A drive unit (12) couples to the fastener to thread it into place. The fastener exerts a clamping force on the components to connect them together. The clamping force created by the fastener produces an equal and opposite tensile force on the fastener. A controller (16) starts and stops operation of the drive unit. The controller controls the drive unit to thread the fastener into place until it exerts a predetermined amount of clamping force on the components. A test unit (18) generates ultrasonic waves and transmits them lengthwise through the fastener. The transit time of the waves through the fastener is then measured. The transit time of the waves is a function of the tensile force on the fastener and, in turn, a function of the clamping force exerted by the fastener.