GB421207A - Improvements in or relating to flying-time and like indicators - Google Patents

Abstract

421,207. Clocks; indicating -apparatus; counting-apparatus. AIR LOG CO., LTD., and MAYERS, H. C., 193, Elgin Terrace, Maida Vale, London. Aug. 22, 1933, No. 23371. [Class 139] [See also Group XIX] In a device of the kind described in Specification 361,663, [Group XIX], for integrating intermittent time intervals, particularly for use on aircraft to indicate actual flying time, and in which the trip-time indicating means is reset to zero by a member which simultaneously winds the clockwork mechanism, one revolution of the winding member corresponds to a plurality of revolutions of the trip-time minute hand. The mainspring 24 is secured at its inner end to the winding spindle 25, and drives through a ratchet 27, and pawl 28, a shaft 31 controlled by an escapement 36, 37, 38, 39. The shaft 31 is frictionally driven and carries gear wheels 53, 54, meshing with gear wheels 52, 55, respectively. The wheel 52 is carried by a sleeve 51 through which the trip-time minute hand 50 is driven at the same speed as shaft 31. The trip-time hours are indicated on a disc 58 visible through an aperture in the dial 18, Fig. 4, and advanced at each hour by a projection 57, Fig. 7, engaging a star wheel 59 rigid with the disc. Normally, the clock is locked by a wire 40, Fig. 1, engaging between teeth of the escape wheel 36, the wire being withdrawn through a linkage 41 when the air pressure in a capsule 12 is increased, for example, when the aeroplane is in flight, so that only flying time is indicated. At the end of each flight the shaft 25 is rotated by a knob 26 to wind the mainspring 24, and through the gearing 55, 54, 53, 52 zeroises the trip-time indicating members 50, 58, the ratio of the wheels 55, 54, causing one revolution of the shaft 25 to result in a plurality of revolutions of the hand 50. A projection 61 on the star wheel 59, Fig. 7, engages a stop 62 at the zero position, and to prevent the slight return or backlash movement of the ratchet mechanism 27, 28 being transmitted to the hand 50, the gear 55 is connected to shaft 25 through a lost motion device shown in Fig. 5. The total flying time is indicated on discs 63 (tenths), 64 (units), 65 (tens), 66 (hundreds), Figs. 2, 4, driven by star wheels in known manner, the disc 63 being driven directly from the wheel 29. In a modification, the hand 50 is secured directly to the shaft 31. The calibration of the dial and the indicating means may be varied. The capsule 12 may be actuated by water, oil or other liquid, and may be replaced by other controlling means. According to the Provisional Specification, the feature of arranging the resetting means so as to be unaffected by the backlash of the ratchet mechanism, may be applied to other time integrating devices.