Miniature mechanical safety and arming device with runaway escapement arming delay mechanism for artillery fuze

In this research, a miniature mechanical SAD (Safety and Arming Device) with arming delay was developed for actual munitions application. Reliable arming delay performance was achieved by applying a runaway escapement system that operates by a rack-and-pinion motion. The miniature mechanical SAD was fabricated using a stainless steel wet etching process that provided not only miniaturization but also a high processing yield. The miniature mechanical SAD performed successfully under the desired safety and arming conditions in lab tests and showed fine agreement with the finite element method simulation results. Field tests were performed with a grenade launcher to validate its performance under the actual firing conditions. One hundred samples that were shot 23.6 m (safety distance) and 200 m (arming distance), and every specific test criterion was met successfully. The new SAD was also found to be appropriate for safe use in artillery fuzes by conducting environmental tests under a variety of temperature, vibration, and impact conditions.