An ordnance actuated or pyrotechnic pin puller is typically used to restrain a mechanism under low to extreme side loads and then rapidly releases them for a clean separation. The pin pullers retain all explosive hot gases with the use of various elastomeric seals. Pin pullers can be actuated by an electrical explosive device (pressure cartridge), a mechanical primer initiated device (gas generator), a linear detonation transfer line (SMDC, FCDC, ETL, RDC) or a laser actuated ordnance device (laser initiated squib or detonator). Function time in most applications is under 20 milliseconds from application of input energy.
The energy from any of these devices expands rapidly in a confined space, resulting in a volume change which drives the pin inside of the pin puller body. Retraction length of the pin is controlled by the envelope of the body. The pins retract rapidly in most applications, creating a mechanical shock when the piston reaches full stroke. Dampeners can be installed into the pin pullers when lower mechanical shock is needed. In many applications, the shock of other devices being released is as great as, or greater than, that generated by pin puller actuation.
A pin puller can be sized for a wide variety of geometries and they can in some cases include switches to verify pin retraction has occurred.