GB827167A - Improvements in and relating to the measurement of thickness in production of sheet and strip material - Google Patents

Abstract

827,167. Electric indicating apparatus. BRITISH IRON & STEEL RESEARCH ASSOCIATION. Dec. 2, 1955 [Nov. 29, 1954], No. 34524/54. Addition to 713,105. Class 40 (1). [Also in Group XXII] In apparatus as described in the parent Specification for measuring the thickness of sheet or strip emergent from a rolling or drawing mill, an alternating current signal is generated in accordance with the actual separation of the work rolls or dies (shown to be proportional to F S 0 + - (and additively compounded with an Mmf alternating current signal in accordance with the separating force F between the rolls to a resultant signal proportional to S 0 + F/Mm# + F/Mwr, where S 0 is the initial setting of the work rolls or dies, Mmf is a constant representing the elasticity of the mill frame, and Mwr a constant representing the elasticity of the work rolls. Fig. 1 shows work rolls 12, 13, rotatably mounted in chocks 14, 15 with a pair of cantilever resistance strain gauges 16, 17 mounted insulatedly on the upper chock, and distorted by sliding plungers 19, 21 carrying ball races 20, 22 contacting the necks of the respective work rolls 12, 13. A further cantilever resistance strain gauge 23 is insulatedly mounted on chock 25 of the back-up roll (not shown), and is distorted by a slidable plunger 26 carrying a ball race contacting the neck of the work roll 12. Strain gauges 16, 17, 23 are respectively connected in A.C. energized bridge networks 30, 31, 32 (Fig. 2); the sum of the outputs of bridges 30, 31 being proportional to the separation S of the work rolls, and the output of bridge 32 being proportional to the separation of the axes of the work and back-up rolls and thus to the separating force F. The output of bridge 32 energizes potentiometer 36 whose F setting represents -and is additively com- Mwr bined with the outputs of the other bridges in meter 37, whose reading is proportional to F F F S 0 + -- + -- = S + --and indicates Mmf Mwr Mwr the thickness of the emergent material. In a 2-high mill (not shown) the separating force is measured by a single strain gauge mounted in a block subjected to the mill load as described in parent Specification, and its signal is combined with the difference of the signals from strain gauges 16, 17 as described above. Strain gauges 16, 17, 23 may be provided at each end of the rolls and their signals averaged. The signal representing emergent thickness may be compared with a potentiometric signal representing required thickness to obtain an indication of thickness deviations.