Direct and indirect initial tightening force measurement apparatus for screw connection, using head for radiating pulse to screw identical to original coupling screw or to coupling screw directly for measurement

摘要

The screw spindle (26) includes motor (1) that drives screwing tool (17) through gear (3), shaft (4), to tighten first screw (18) to flange (20) and lid (19). A second screw (11) identical to the first screw, with ultrasonic sensor (9) is coupled between the screwing tool and gear. An ultrasonic test head radiates pulse to first screw or to second screw during direct and indirect measurement. During indirect measurement of the initial tightening force of the first screw, the test head radiates ultrasonic pulses on second screw (11) and the waves reflected by the tightened end of the screw are received and processed by electronic controller (25). During direct measurement, the head radiates waves directly to the screw (18) and reflected waves are received through the ultrasonic coupler (5) and processed by the electronic controller to determine straining of screw threads and hence bias force. An Independent claim is also included for direct and indirect measurement of screw initial tightening force in motor driven screw spindle.