GB736674A - Improvements in rolls for transversely stretching or contracting webs - Google Patents

Abstract

736,674. Stretching webs transversely. ROBERTSON, J. D. Feb. 5, 1951, No. 2809/51. Class 100 (1). A roll for transversely stretching or contracting webs of flexible sheet material comprises an axial shaft, a cover of resilient material and a number of annular members spaced along the shaft for supporting the cover, the central portion of the shaft being curved and the end portions being straight so that sub. stantially equal stretching will be imparted to webs of different widths ranging from that corresponding to the curved part only of the roll to that corresponding to the full width of the roll. A rigid shaft 10, Fig. 1, having a curved central portion and straight end-portions is mounted in clamps 12, such that the shaft may, by loosening the clamps, be swung about the axis passing through the clamps. A series of spaced sleeves 14 are rotatably mounted by ball-bearings on the shaft 10, while a sleeve 16 of rubber encloses the sleeves 14 and rotates therewith when engaged by a travelling web. In a modified construction, Fig. 5, the central portion of the shaft is constituted by a leafspring section 24 which is secured at one end to a straight shaft section, while at the opposite end it fits into a split clamp member 48. The leaf-spring section comprises a multiplicity of leaves of varying widths in stacked relation to provide a leaf spring of circular cross-section. Ball-bearing units 28 surrounding the spring section and spaced by sleeves 40 carry rollsections 38 which support the sleeve 16. The clamp member 48 has tapering walls co-operating interiorly with a clamp member 50 fixed to a straight shaft section 20. A screw 52 rotatably mounted, but retained against axial movement in the section 20, screws into the member 48, such that by turning a squared portion 53 the member 48 may be clamped or unclamped by the member 50. When the leaf spring 24 is unclamped, it may be bowed by an arrangement comprising a bracket fitting on each end of the shaft, the brackets being adjustable towards each other by rotating a shaft having oppositely threaded ends screwed into the brackets. The parts of the sleeve 16 which surround the straight parts of the shaft may be made of harder rubber than the central part so as to be more resistant to wear. Specification 613,450 is referred to.