Latches are an essential machine element utilized by all sectors (medical, military, industrial, etc.) and there is a growing need for active latches with automatic release and reset capabilities. Shape memory alloy (SMA), due to its high energy/power densities, is an attractive alternative actuation approach to conventional methods (electrical, hydraulic) because it is inexpensive, lightweight, compact and has a fast heating response times. This paper introduces the T-latch which is based upon a compact spooled SMA rotary actuator. The T-latch can engage passively, maintain a structural connection in multiple degrees of freedom with zero power consumption, actively release very quickly (< 20 ms) and then repeat operation with automatic reset. To provide the basis to apply this latch across sectors, operational behavioral models are summarized for the key states of engagement, retention, release and reset. To demonstrate the technology, a proof-of-concept prototype for automotive panel lockdown was designed, built and experimentally characterized for the basic operational states along with studies of the effects of power, seal and reset force. The results from this study indicate promising suitability of the T-latch technology for a broad range of industrial applications.

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