GB393272A - Improvements in or relating to aircraft altimeters and barometers - Google Patents

Abstract

393,272. Barometers and altimeters. KOLLSMAN, P., 47, Dinsmore Place, Brooklyn, New York, U.S.A. Nov. 20, 1931, No. 32233. [Class 106 (ii).] A barometer or altimeter supports pressures solely by the strength and elasticity of its walls and without the support of any internal or external spring force. In a simple form, Fig. 6, the capsule 10 has centre pieces 16, 17, the former mounting the capsule and the latter being connected to the temperature compensator link 18 connected to gear segment 19 pivoted at 20, counterweighted at 21 and engaging with a pinion 22 for rotating the pointer 23. The walls of the capsule 10 remain concave up to the maximum reading and are provided with a plurality of uniform corrugations 14 of substantially uniform depth slightly less than that of the outermost corrugation which runs to the flange reinforcement 15. A plurality of capsules can be axially secured together by centre pieces which may be small bars or discs having ends or faces directly externally secured to the capsule walls, so that the boxes may be close together and operate as a unit. The altimeter 24, Fig. 2, has two standards 34, 35 adjustably sprung apart for setting purposes by the screw adjusted leaf springs 37, 38 and rigidly connected to the disc 32 rigidly secured to the flange 33 at 28. The centre piece 16 of the capsule 10 extends through hole 42 in standard 35 and is adjustably locked by setscrew 43, whilst the centre piece 17 is connected to the link 44, connected to the set-screw adjusted resilient arm 45 of the shaft 46 journalled in disc 32 and in bracket 47 mounted on standard 34. A bendable strip 56 of different metal is secured to the link 44 to form a temperature compensator. Shaft 46 rotates segment 49 and hence pinion 50 connected to spindle 51 carrying pointer 52 reading on the dial 26 having gear teeth 29 engaged by pinion 30 turned by knob 31 for any desired setting. The spindle 51 is journalled in disc 32 and in plate 53 and carries a hair spring 54 which may be supported against lateral deflection, by disc 55 secured to the spindle, for accuracy in reading if the pointer is arranged to make many rotations. Fig. 5 shows a temperature compensator 57 consisting of an elongated straight bimetallic strip passing through a hole in, and adjustably screw-connected to, the element 58 attached to the wall 11 of the capsule 10. A link such as 18 or 44 is pivotally connected to the end of the compensator 57. The capsule 10 and compensator strip 57 form a unit which can be adjusted for temperature compensation by longitudinal movement of the strip 57 relative to the element 58 before being assembled in the instrument and connected to the mechanism for operating the indicating means. To facilitate calibrating the altimeter, a light tension spring 60 may be connected to the capsule 10 and to an arm 61 of standard34.