GB449128A - Improvements in or relating to temperature-pressure altimeter - Google Patents

Abstract

449,128. Altimeters. JACKSON, L. MELLERSH-, 28, Southampton Buildings, Chancery Lane, London.-(Kollsman Instrument Co., Inc. ; 1, Junius Street, Brooklyn, New York, U.S.A.) Sept. 23, 1935, No. 26347. [Class 106 (ii)] The instrument comprises an altitude indicator, barometric mechanism responsive to the temperature of the atmosphere-operating said indicator, and a variable mechanism settable to temperatures at the ground to vary the action of the barometric pressure means or the temperature means or both. The barometric capsule D is carried in an insulated casing A with a vent to the atmosphere but in which the temperature changes slowly. Movement of the capsule is transmitted through a link 23 and arm 22 on a spindle 16 to the latter and hence through sector 18 and gear 14 to a pointer 9 moving over a scale 8 on a rotatable annulus 7. This carries a washer 12 reading against a fixed scale 11 of millimeters of mercury visible through a window 10 of the annulus. The upper end of the spindle 16 is carried in a fixed bearing, but the lower end is carried in a lever 21. The fulcrum of the lever 21 is carried by the forked end of a sliding rod 35 which may be moved by a cam 38 set from a button 66 operating through gears 64, 63, 62, the latter of which carries a ground temperature washer 61 working in an arcuate slot separating the scale of temperatures 49 from the plate 6. A temperature element, comprising a bulb or tubular spiral is located on a wing or strut and freely exposed to the free air in which the plane is moving. This bulb together with a capillary tube connecting it to a Bourdon tube C and the latter is filled with liquid. The movement of the Bourdon tube is transmitted through sector 42 and spindle 45 to a temperature pointer 53 indicating free air temperature. Its movement is also transmitted through lever 25 and link 31 to the lever 21. The transmission to the altitude pointer 9 is thus affected by the temperature element and the setting of the ground temperature by knob 66 in addition to the movement of the capsule. In addition, the ring 7 may be moved through circumferential teeth in mesh with gear 82 in one with a knob 80 so that washer 12 points to a barometer pressure corresponding to the altitude of the field relatively to which the altitude is to be indicated by the pointer 9.