Computer Simulation of Artillery Safing and Arming Mechanism in Aeroballistic Environment (Involute Gear Train and Straight-Sided Verge Runaway Escapement)

摘要

A computer simulation was developed for a complete artillery safing and arming (S&A) mechanism which must operate in a projectile that experiences spin, precession, and nutation. This mechanism contains a straight-sided verge runaway escapement, a two pass involute step-out gear train, and a spin driven rotor. The mathematical model treats three motion regimes of the associated escapement (i.e., coupled motion, free motion, and impact). The computer program is well adapted to parametric studies, and it allows the use of pallets with arbitrarily selected centers of mass. Also, when actual aeroballistics data are used, it determines the behavior of the S&A mechanism in a projectile with pathological motion. A sample simulation, with the dimensions of the M739 S&A mechanism, was run at 30,000 rpm with small precession and nutation velocities. It showed essentially the same number of turns-to-arm when only spin is present.