block that keeps wheel from moving
軔 centers on a physical block that stops a wheel from moving, like a chock or brake. Its meaning is narrow and concrete, without common abstract extensions.
軔 combines 車 (vehicle, wheel) and 刃 (blade), likely suggesting a blade-like block that stops a wheel. The exact historical development is uncertain, but the component combination fits the meaning of a wheel chock.
A wheel (車) meets a blade (刃) that digs in and stops it from rolling. Picture a sharp metal chock wedged against a cart wheel.
For ジン, imagine a jean-clad worker jamming a block under a wheel: jean -> ジン, and the block stops the wheel.