With accuracy rivaling that of strain-gauges, the USM-3, Ultrasonic Bolt Meter, defines the state of the art in the measurement of the actual clamp load produced by tightening a threaded fastener. The USM-3 can measure fastener elongation or the resulting load, very accurately in fasteners of virtually any material from 1/2 inch to over 50 feet in length.
The USM-3 allows up to 30 hours field operation from 4 'C' cell alkaline batteries.
The measurement is achieved by determining the change in the transit time, of an ultrasonic shock wave along the length of the fastener as the fastener is tightened by any method. The on-board microcomputer automatically interprets this time measurement to display the elongation or load in the fastener. Through the use of high speed digital signal processing and automated diagnostics, the USM-3 minimizes the requirements for extensive operator training.