GB162547A - An improved indicating device applicable for apparatus employed for measuring quantities depending on two variable factors - Google Patents

Abstract

162,547. Gros, P. M. F. Dugit-, (known as Dugit, M.). May 13, 1920. Multiple-indication apparatus; index hands and pointers; modifying scale of readings.-In apparatus for indicating values dependent upon two variables, two pointers, one or both of which is curved, are mounted coaxially and moved in accordance with these variables so as to give, by their intersection against a series of stationary curves, the values required. The pointers may be replaced by lines or a series of lines on transparent discs. In an instrument for measuring the air-speed of aircraft, a curved pointer 27, Figs. 1 and 2, actuated according to the pressure in a Venturi tube 15 by means of connections including an aneroid chamber 17, an oscillating plate 21, and toothed sector 24, co-operates with a straight pointer 13 controlled by the static air pressure through similar pressure and transmitting devices 1, 6, 9, and the intersection of the pointers is read to give the air-speed, against a series of curves V<0>, V<1>, V<2>. The pointer 27 may take the form of a curved rod 37, Fig. 4, a circular rod, Fig. 5, or a segmental plate. In the form shown in Fig. 8 a third factor is introduced; one of two transparent discs 14, 27<1> rotated according to the two variables bears curves T<0>, T<1> T<2>, representing densities corresponding with different temperatures, and the intersection of the curve concerned with a fixed pointer 13<2> enables the speed to be read as shown by the curves V<0>, V<1>, V<2>. The invention may be applied to electrical power measuring instruments and to devices for checking or controlling a dual manual drive which has to maintain a given resultant.