Apogee Designs Ltd. (Baltimore) has invented a tamperproof fastener that cannot be overtightened or undertightened.

Apogee's Eclock eccentric locking fastener can be made from steel or titanium and feature any thread profile. The head of the fastener has a cylindrical pocket. At the bottom of the pocket, slightly off center from the fastener's axis, is a plastic or aluminum shear pin.

The installation tool captures this pin and rotates it eccentrically to drive the fastener. The tool tip is easily inserted or withdrawn from the pocket. The eccentric action of the tool prevents "cam-out," or the tool tip jumping out of the fastener during installation. At a precalculated torque, the pin shears off and the tool spins freely within the pocket, preventing further tightening.

Once installed, the fastener cannot be reused, and the side walls of the pocket are impossible to grip with standard screwdriving tools. A molded rubber foot can be pressed over the head after installation for aesthetics, functionality or further tamperproofing.

For more information on tamperproof fasteners, call Apogee Designs at 410-633-6336, visit www.apogeedesigns.com, or eInquiry 21.