GB415458A - Improvements in indicating instruments such as altimeters and the like - Google Patents

Abstract

415,458. Barometric altimeter. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Feb. 24, 1933, No. 5680. Convention date, Feb. 25, 1932. [Classes 106 (ii) and 106 (iv).] An indicating-instrument is provided with means for setting it to indicate under a different condition and to indicate, independently of the indicating action, the condition for which it has been set. As applied to an aircraft-navigating instrument such as an altimeter the aneroid capsules 7, 8 are carried by a supporting member 9 and the movement in response to pressure variations is transmitted through a temperature compensating element and link 10 to a rock shaft 15. The capsules are also connected by links to a pivoted counterweight and spring to balance the system in order to prevent movement due to vibration, acceleration forces &c. The movement of the rockshaft 15 is transmitted to a countershaft 39 by gear sector 37 and pinion 38 and hence by gears 41, 42 to a hollow shaft 43 at the end of which is secured a large pointer 44 moving over a dial 45 having a scale marked in hundreds of feet. A concentric scale is provided marked in thousands of feet and co-operating therewith is a small pointer 47 driven by gears 48, 49 and a shaft 50 passing through the shaft 43. The capsules 7, 8 are carried by a screwed stem 9 which is prevented from rotation by a stop 65 sliding in a hole 67 but which may be moved axially together with the capsules by turning a nut 63 mounted for rotation without axial movement. The nut has secured to it a worm gear 62 operated by a worm on a shaft 57 which may be turned through gears 53, 54, 55 operated by a turn button 60. The shaft 57 is extended and actuates a Veeder counter 68 through bevel gear 71, 72. In use, before a flight the altimeter is adjusted to read zero at the height of the ground at which it is intended to land. To do this the knob 60 is turned so that the device reads, say 4000 ft. which is the height of the landing ground, this being registered on the counter. On approaching the landing ground the aviator will know exactly at what height above the landing ground he is flying.