Numerous varieties of fasteners have been developed in response to the diversity of applications for which fasteners can be used. As manufacturing processes become more automated, there has been an increased emphasis on developing fasteners which simplify and facilitate assembly, yet which are capable of reliably securing the particular members being joined. Such a need particularly exists in the electronics industry for the purpose of reliably securing circuit boards and various components to a support frame or chassis of an enclosure, cabinet and casing.
Fasteners suitable for the above types of applications generally must be capable of being installed without damage to the circuit board or component and the support member to which it is to be secured, yet must also provide secure and reliable attachment so as ensure sufficient vibration resistance. Conventionally, threaded fasteners are widely used to secure circuit boards to a chassis, at times incorporating a self-locking feature to discourage the fastener from becoming loose due to vibration.
However, a significant disadvantage associated with the use of threaded fasteners is that they require a rotational motion for installation. In terms of automated assembly methods, fasteners that require a rotational motion add significant costs to the assembly process. When manual assembly methods are used, threaded fasteners are often undesirable in that carpal tunnel syndrome has been linked to the ratcheting motion required to install such fasteners.
Consequently, various types of nonthreaded fasteners have been proposed, such as fasteners which have a snap-action operation. Snap-action fasteners generally have one or more members which toggle between two stable positions, one of which defines a fastening position while the other is an assembly or release position. It would be desirable if an improved fastener incorporating a bi-stable mechanism were available to provide a reliable, reusable fastener for joining together two or more members, such as a circuit board and a support chassis. Such a fastener would preferably enable a straight push-in type assembly, facilitate installation and removal procedures, and obviate the requirement for additional fasteners and special tools for assembly and disassembly.