Method and apparatus for visually locating the position of a floating piston inside of a cylinder

Claim 1

A recuperator assembly of a recoil mechanism of a weapon system wherein said recuperator assembly includes a cylinder with a piston therein separating the interior of the cylinder into a high pressure fluid chamber and a high pressure gas chamber, means adapted for visually displaying the interior of the gas chamber and indicating the position of the piston in the cylinder including sight glass means carried by said cylinder for visually displaying the interior of said gas chamber to the exterior thereof, said sight glass means comprising a window located in an end wall of said cylinder, movable means in the gas chamber including a connection movable with said piston, said movable means being positioned for viewing through said sight glass means and being movably responsive to piston movement through said connection and, indicia means on said movable means viewable through said sight glass means for indicating the position of said piston in said cylinder, said movable means comprising spool means carried by said end wall of said cylinder and comprising first, second and third spools, said first and third spools being co-axial and movable with each other, said second spool being located at a distance from said first and third spools in vertical alignment with said third spool, said second spool being positioned with its surface located in the line of sight of said window and having indicia means carried thereby, said connection comprising a cable carried at one end by said piston and wound on and attached at its other end to said first spool, a constant force load spring attached to, carried by and wound partially on said second spool at one end thereof, said spring being attached, carried by and wound on said third spool.