Active Distributed Attachment Surfaces: Distributed Latching Technique and Demonstration

Latches are essential mechanical elements used to controllably connect multiple bodies throughout industry. Latches conventionally attach bodies at a single point or at a few discrete points, and are designed for multiple operation cycles. Actuator controlled latches, minimize the amount of complexity and costs involved with installation and removal by making the attachment between structures controllable, tool-free and fast. However, the use of multiple single point fasteners carries additional part count, material costs, and labor associated with installation and removal, and can creating load concentrations at attachment sites. Alternatively, surface attachments, such as traditional hook and loop mechanisms, distribute structural connection over an area or across many points reducing stress concentrations, allowing engagement of multiple bodies, maintaining structural connections in nonspecific locations and orientations and reducing labor costs to install and detach bodies. However, performance limitations of conventional surface attachments, such as low retention force, restrict potential applications. An active distributed attachment technique has the potential to increase the performance of conventional distributed attachments, as well as overcome the complexity and operation of conventional point attachments. This paper introduces three active distributed latch approaches (Pegboard, Interlocking Teeth, and Active Velcro) that utilize lightweight, compact SMA actuation. Proof-of-concept prototypes were built, and tested experimentally to investigate the engagement, retention, and release performance. The best performing of the three is demonstrated in a full application scale. The first generation prototypes improved upon the performance of conventional surface attachments and show promise in maintaining the necessary structural attachment for industrial applications.