Piston operated slide valve

Claim 1

A piston-operated slide valve comprising a cylinder having an end wall provided with a central opening therein, a piston disposed in the cylinder, a piston stem secured to the piston and slidably mounted in said opening, said stem extending outwardly away from said end wall and provided outside of the cylinder with a longitudinal slot extending through the stem, a valve slide fitting in said slot and projecting from the opposite sides of the stem, the exposed sides of the slide being flat and parallel, the piston being movable back and forth in said cylinder to move said slide between two fixed positions, a stationary block secured to said end wall and having a flat surface engaging one of said flat sides of the slide, a floating block having a flat surface engaging the other flat side of the slide, a single pair of studs mounted in he stationary block and straddling said stem beside the slide, the floating block being provided with openings therethrough slidingly receiving said studs, the slide having a passage therethrough connecting its flat sides, said blocks having aligned passages therethrough registering with said slide passage when the slide is in one of said fixed positions, a pressure bar slidably mounted on the portions of said studs projecting from the floating block and, having a projection between the studs engaging the floating block in the central longitudinal plane of the slide, springs mounted on the studs in engagement with the outer surface of said bar, and nuts screwed on the studs and compressing the springs to press said bar projection against the floating block.