Study of Damped Set-Back Pins for S and A Mechanisms.

摘要

The damped set-back pin study program was for the design,testing,fabrication,and delivery and damped set-back pin assemblies for use in a safe and arm device for artillery munitions. This damped set-back pin assembly is one of two safety features on a S and A device used in the M739PD/XM587ET fuzes for a rotating projectile. A pin,porous disc,return spring,floating O-ring,and sleeve comprise the selected damped set-back pin assembly design. Damping is acquired through the proper regulation and control of the air flow rate,return spring force,and the O-ring friction. Tests conducted to determine the design parameters and the structural integrity of the pin system included O-ring/lubrication compatibility testing, O-ring friction testing,flow rate measurements through porous sintered metal discs,and selected MIL-STD-331tests. Two minor modifications were made to the existing bottom plate to incorporate the damped set-back pin --the boss (closure disc end) that housed the present set-back pin assembly was removed and Emralon lubrication was added. All test and analysis results proved that the floating O-ring concept is feasible. (Author)