GB422265A - Improvements in or relating to indicating instruments such as altimeters - Google Patents

Abstract

422,265. Indicating - instruments. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. April 5, 1933, No. 10197. Convention date, April 6, 1932. [Classes 106 (ii) and 106 (iv)] Comprises an instrument such as an altimeter having a sensitive element influenced by varying conditions and one or more pointers and scales, characterized in that setting means are provided for producing a relative movement between the scales and pointers for adjusting the instrument to obtain a desired indication when a predetermined condition is reached, the setting means including part of the transmission mechanism so arranged that the relative movement may be produced separately by the sensitive element and by the setting means. The frame supporting the mechanism is secured by screws 12 to the closed back of a casing 10 provided with a glass face and open to the static atmospheric pressure. Aneroid capsules 18 are adjustably secured to the frame by a screw 19 and the movement is transmitted by a pivoted link 23 connected to a temperature compensating element 24 attached to the capsule. The other end of link 23 is pivoted to an arm 26 attached to a collar 27 fixed to the shaft 28. From this shaft movement is transmitted by double gearing to two indicating needles 36, 37 of which the former moves at ten times the speed of the latter. The shaft 28 is surrounded by a sleeve 31 to which the sector 35 is secured which continues the transmission to the pointers. Secured to the collar 27 is a bracket 32 in which is journalled a worm 33 in mesh with a worm wheel 34 on the sleeve 31. A worm wheel 43 in one with the worm 33 meshes with a worm 46 journalled in the bracket and connected by a flexible shaft 47 to a gear wheel 48. When it is desired to alter the setting of the needles without breaking operative connection of the transmission, the knob 51<a> is pushed in against the influence of springs 53, 57 and the friction disc 54 moved to engage the face of a sector 56 and thus brake the indicating mechanism, a wheel 49 being at the same time slid into gear with toothed wheel 48. By turning the knob the worm gearing 46, 43, 33, 31 may be operated through the shaft 47 to turn the sleeve 31 relatively to the shaft 28 and adjust the indicating needles as desired. The wheel 48 also gears with the first wheel of a Veeder counter which thus indicates the setting given to the indicating needles.