Fired practice rounds counter and display - uses inertia to compress spring and to rotate disc using sawtooth surfaces under inertia and spring force

摘要

A disc is mounted transversely to the axis of the munition on a shaft which lies along the axis of the munition. Under the acceleration, at launching, the assembly comprising the counting disc and two end discs moves towards the rear of the munition against a spring. The sloped spigot on the rearmost disc corresponding to sawtooth cutouts in the centre disc allows a half step rotation under acceleration while the centre disc is disengaged from the front disc. In steady flight the spring returns the assembly towards the front of the munition and the meshing of the front disc sloped spigot with the internal sawtooth of the centre disc causes the latter disc to rotate through a second half step.