Roll for the pressure treatment of web material, especially paper

Claim 1

A ROLL FOR THE PRESSURE TREATMENT OF STRIP MATERIAL COMPRISING A TUBULAR HOLLOW BODY FREE TO REVOLVE AROUND AN AXIS AND HAVING AN INNER PERIPHERY AND AN OUTER PERIPHERY WHICH OUTER PERIPHERY IS ADAPTED TO BEAR AGAINST THE STRIP MATERIAL ALONG A LINE OF CONTACT, A STATIONARY CORE, AND SUPPORTS FOR SAID CORE AT ITS ENDS, IN COMBINATION WITH A CYLINDER DISPOSED IN SAID CORE, A PISTON IN SAID CYLINDER AND A FLUID MEDIUM IN SAID CYLINDER ADAPTED UNDER PRESSURE TO IMPINGE ON SAID PISTON FOR THE PURPOSE OF PRODUCING A PRESSURE ON THE INNER PERIPHERY OF THE HOLLOW BODY ON THE SIDE WHERE IT IS ADAPTED TO BEAR AGAINST THE STRIP MATERIAL, A SLIDING SHOE ON THE OUTER END OF SAID PISTON DISPOSED IN SAID CYLINDER AND BEARING AGAINST THE INNER PERIPHERY OF THE HOLLOW BODY ADJACENT THE SIDE WHERE THE OUTER PERIPHERY IS ADAPTED TO BEAR AGAINST THE STRIP MATERIAL, SAID SLIDING SHOE HAVING A CYLINDRICAL SECTION WITH A CONTINUOUS OUTER SURFACE OF A RADIUS OF CURVATURE SUBSTANTIALLY EQUAL TO THAT OF THE INNER PERIPHERY OF THE HOLLOW BODY, BY WHICH OUTER SURFACE THE SLIDING SHOE BEARS AGAINST THE INNER PERIPHERY OF THE HOLLOW BODY, SAID OUTER SURFACE EXTENDING FROM THE INNER LINE OF THE HOLLOW BODY SITUATED OPPOSITE THE LINE OF CONTACT OF THE OUTER PERIPHERY OF THE HOLLOW BODY WITH THE STRIP MATERIAL, AND IN BOTH PERIPHERAL DIRECTIONS, BUT NOT FURTHER THAN PERPENDICULAR TO THE RADIAL STRAIGHT LINE FROM THE AXIS OF THE HOLLOW BODY TO THE LINE OF CONTACT TO THE STRIP MATERIAL, WHEREBY A SLIDING MEDIUM IS PROVIDED BETWEEN THE FACE OF SAID SHOE AND THE INNER PERIPHERY OF THE HOLLOW BODY, SAID PISTON HAVING AN OIL DUCT THERETHROUGH.