GB1169381A - Process and Apparatus for Measuring the Distribution of Tensile Stresses Over the Width of Strip Material - Google Patents

Abstract

1,169,381. Measuring strip tension electrically; measuring stress. W. MUHLBERG. Sept.28, 1966 [Oct. 18, 1965], No.43259/66. Headings G1N; G1S and G1W. The variations in longitudinal tension across the width of a strip of material moving over a roller 1, Figs. 3, 3a, are measured by sensing at various regions across the width of the roller, the deflections of the outer shell of the roller 1 towards a fixed axle 3 on which it rotates. The shell rotates on bearings 2, and the deflection transducers each consist of a ring of magnetically permeable material 4 attached to the shell, and two U-shaped magnetically permeable cores 5, 5<SP>1</SP> attached to diametrically opposite portions of the axle 3 so as to form air-gaps between the ring 4 and the poles N1, N2, S1, S1 of the cores. The gaps are differentially varied by deflection of the roller shell 1, and a secondary coil on one pole piece of each core has induced in it, from a primary coil on the other polepiece of the corresponding core, a voltage proportional to the deflection, the two secondaries being appropriately connected in a bridge. Alternatively, the deflection transducers may be strain gauges (7a, 7b, Figs. 5, 5a, not shown) mounted on the inner race 6 of a roller bearing 9 which carries the roller outer shell 1, and which has its inner race 6 fixed to the axle at one portion of its circumference by bolts 8. Deflections of the inner race relative to the fixed portion are produced by stress variations in the strip and are measured by the strain gauges. Alternative devices for measuring deflections of the roller 1 include pneumatic jets with back pressure sensors. The measured distribution of stress may be used to control the thickness settings at various stands of a mill, or to correct roll cambers.