A low-cost RFID-based torque and tension sensor developed by NASA for high-performance fasteners offers the ability to remotely and quickly verify that a given fastener is torqued properly. Applied to high-performance fasteners such as bolts used in sophisticated high-tech equipment and systems, the technology can deliver cost-savings over the life of the fastener and its host system.
This asset management tool is also extremely low cost compared to current torque sensing wrenches and comparable technologies. It offers performance and safety improvements as well. The motivation behind this invention was the catastrophic event in which an NOAA satellite sustained heavy damage after falling from a Turn-Over-Cart (TOC). The root cause was a configuration change in which the TOC-24 bolts had not been secured properly to the TOC. The quality assurance, tension monitoring and configuration management associated with proper torquing of fasteners can now be largely automated and provide a higher degree of safety.
The system replaces traditional designs by using standard bolts in conjunction with an RFID ring integrated circuit (IC), antenna layers (top and bottom), a flat washer and a spring washer. The antenna, RFID ring and spring comprise a sensor tag that can be remotely interrogated. When sufficient torque is applied to the bolt, the RFID circuit is enabled, allowing it to communicate with remote RFID interrogators (typically three to 30 feet away depending on the tag antenna design). A new level of automation and sensor telemetry is now possible due to this technology's ability to read longer ranges than the present systems.
This is a passive device meaning that even when the RFID ring circuit is complete; it will only provide an RF response when activated by an external reader. The RFID IC (chip) is a standard EPC Global Class 1, Gen 2 design that is commercially available, and is routinely employed in tracking and supply chain logistics applications.
The technology is available for licensing and commercial development.