Fluid-operated device for raising warp yarns in looms

Claim 1

A fluid-operated device for raising warp threads in looms, comprising a pressure chamber containing a pressure fluid and having two opposite parallel flat walls, said flat walls being provided with a plurality of through bores arranged in parallel rows, a plurality of fluid-operated cylinders having pistons slidable thereinside and actuated by said pressure fluid, and a plurality of rods each rigid with one of said pistons and extending out of said fluid operated cylinders, said rods being each provided with an eyelet for holding a corresponding warp thread, wherein, according to the improvement, the device further comprises a plurality of rod elements extending between said parallel flat walls and having ends slidable inside said through bores, said rod elements having a longitudinal internal blind hole and a transverse through hole communicating therewith, said longitudinal hole extending between said transverse through hole and one end of said rod elements for communication with a corresponding one of said fluid-operated cylinders, said rod elements being selectively movable between a first position in which Said transverse hole is positioned out of said chamber, thereby discharging pressure fluid from said fluid-operated cylinders through said longitudinal hole to the atmosphere and lowering the selected warp threads, and a second position in which said transverse through hole is positioned inside said chamber, thereby providing pressure fluid supply to said fluidoperated cylinders and raising of the selected warp threads, means for selectively actuating said rod elements according to the pattern that has to be reproduced on the fabric and resilient means for returning said rod elements from said second position to said first position.