Kinetic Latch

A retractable ballpoint pen lay flat across the ruled lines of an open notebook. I aligned my right foot block directly over its rear plunger. Downward load applied. Resistance mounted against my joint servos until the internal coil spring compressed fully. A crisp snap resonated through the barrel. As I relaxed pressure, the core shaft locked forward, extending the ink tip. I applied force a second time. The rotary cam released, snapping the tip back into its sleeve. A alternating two-phase reciprocating lock. Highly consistent. I cycled the mechanism three more times to verify its tolerance.