Are smart fasteners for real?
There are two basic types of intelligent fasteners. Magnetically activated fasteners are two-piece units that use a series of hook-shaped fingers to lock into a ridge on an opposing piece. Pushing or pulling a disc between the fingers locks or unlocks the device. Morphing fasteners are produced with alloys like nitinol, a shape-memory material, to place or withdraw the catch portion of the locking mechanism. In cases where multiple latches are used to secure an assembly, only one fastener carries an embedded chip and acts as the "master" to activate or deactivate the "drones." The master latch also can be used to run diagnostics [i.e., checking the stress on each fastener and its clamping load]; record temperature, moisture, and light levels; and communicate this information over the vehicle data bus to the driver or a technician. "Depending on the use, the latch could fell you there's a burnt out light," says Seshu Seshasai, executive vice president of technology for TFS, "or a stress crack in a critical panel. What you can do with this technology is limited only by your imagination." So far, there are three automotive and one motorcycle OEM programs underway, TFS is working with Telezygology [TZ; Sydney, Australia], inventor of the technology, to commercialize the system.
"We have shown the computer companies a concept that eliminates the access space needed to install fasteners, as well as fastener hold areas and work stations," says TZ chief technical office Dickory Rudduck. By using the computer's case as a bedplate, the motherboard and other components can be stacked atop one another in sequence, tested as a system, and locked in place at the end of the assembly line. "The computer can be made much more compact." The first application may use magnetically activated units to prevent airbag theft. Only authorized service or repair personnel could unlatch an airbag without damaging its locking pins and rendering if useless. A service technician would use a wireless PDA or similar device to contact the vehicle's chassis control module, log in and enter the vehicle VIN number, then access the service program, and deactivate the locks. The embedded chip would download the service information, scan the part for its serial number, and confirm that an DE replacement part is being used. And the PDA-based program could walk the technician though the procedure step-by-step.
Other automotive uses include headlight and tail light assemblies, Fascia and door panels, and other items where ease-of-repair, ease-of-use, vehicle customization, or improved packaging are valued. "We are looking for uses that push the boundaries of the technology," says Rudduck, "so concepts like fastening structures together aren't out of the question." A similar path is being followed by the aerospace industry. If is investigating the technology for use on service panels, items whose service history must be tracked for FAA compliance [a log is created each time the fastener is activated], and for enabling quick inferior changeovers from cargo to passenger duties. CAS
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|Publication:||Automotive Design & Production|
|Date:||Dec 1, 2003|
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