All types of existing hand-powered and powered production assembly tools, including low-cost impulse and impact tools, can be easily adapted for precise load control with ultrasonic fasteners. The transducer is configured so that it can be pulsed and read using a single, inexpensive, spring-loaded contact embodied into the drive of an existing tool. The return path of the signal is provided through the tool’s socket.
The LoadMaster 3300 is connected to the tool or incorporated in the housing of the tool itself. The LoadMaster generates the transducer excitation pulse, makes the precision ultrasonic pulse-echo time-of-flight measurements and translate these measurements into precise load readings, which are read by the assembly tool controller as the fastener is being tightened. Only minor software modifications to an existing standard tool controller are required to monitor and stop on the required load, instead of torque. Eventually, with ultrasonic fasteners, torque and angle transducers could be eliminated allowing a significant reduction in tool cost.
The use of impulse and impact tools with ultrasonic fastener technology has the potential to revolutionize fastener assembly in a number of industries. Modified impact and impulse tools offer an order of magnitude reduction in tool cost, an order of magnitude improvement in tightening accuracy (±30% to ±3% [3σ]), and an approximate 50% reduction in assembly time.