GB821557A - Improvements in or relating to indicating instruments - Google Patents

Abstract

821,557. Final indicators for measuring systems. DEUTA-WERKE (VORM. DEUTSCHE TACHOMETER-WERKE) G.m.b.H. Sept. 17, 1956 [Nov. 23, 1955], No. 28297/56. Class 40 (1). [Also in Groups XXXIII and XL (c)] A cathode-ray tube indicator comprises a cathode-ray tube with a substantially flat rectangular screen and a planar electron beam producing a line image on the screen which is deflected transversely to itself or orientated in accordance with the magnitude of a quantity to be measured. Fig. 1 illustrates an aircraft instrument panel comprising a plurality of such indicators, scalar quantities such as engine speed and altitude being displayed as vertical displacements of the line images on the vertical screens 2 .. 6 and angular quantities such as heading and artificial horizon being displayed by orientation of the line images on the horizontal screens 7, 8, 9. The controls for each vertical indicator are arranged so that the central position of the image corresponds to the desired value of the input quantity, these datum positions being in horizontal alignment. The images may be blanked out when in their datum positions to prevent screen burn and the image focus may be varied in accordance with the deviation of the image from its datum position. The calibration scales may be adjacent the screens as shown or they may be in the form of self-luminous lines on the screen. Each indicator tube 33, Fig. 4, may be mounted in a rectangular metal screening case 34 which can be plugged into the instrument panel, the front edge 39 of the case 34 having an inwardlysloping flange against which the flat screen of the tube abuts; the scale 41 may be applied to the side flanges; cut-outs or projections 40 in the top and bottom flanges facilitate removal of the case. If the image is displaced to either end of the screen, the electron beam impinges on an electrode 38 to actuate an indicating or safety relay device.