Abstract: Apparatus and methods for fitting mechanical parts to minimize prevent free play are described. An apparatus having a piston is designed so as to restrain the piston before actuation, and so as to allow the piston to gain momentum before striking an object. The described apparatus are applicable to devices involving shearable elements. An embodiment of the invention relates to a pyrotechnically activated valve incorporating such features to minimize free play in conjunction with such features so as to restrain the piston and also allow the piston to gain momentum.

Abstract: Apparatus and methods for fitting mechanical parts to minimize prevent free play are described. Additionally, a design for an apparatus having a piston, which restrains the piston before actuation and which allows the piston to gain momentum before striking an object, is detailed. The described apparatus are applicable to devices involving shearable elements. An embodiment of the invention as a pyrotechnically activated valve incorporating such features to minimize free play in conjunction with such features to restrain the piston and also allow the piston to gain momentum is described.

Abstract: An initiator device for activating air crew escape systems comprising a housing of elongate cylindric configuration defining a central chamber having a propellant gas discharge bore at one end and being open at the other end for receiving and static pressure mounting in the central chamber a pyrotechnic cartridge that is held in mounted position by a separate screw threaded head screw threadedly mounted in the housing open end, with the cartridge including a metallic body defining a compression chamber having at the portion of same that is engaged by the housing head, and having a piston received in the compression chamber that is frangibly secured to the cartridge body; the cartridge body also defines a separate pyrotechnic material receiving chamber that is open to the body compression chamber with a column of suitable pyrotechnic materials, tailored in light of the job to be done by the initiator, being mounted in the pyrotechnic material receiving chamber having a head end and terminating with an initiato