GB130356A - Improvements in or relating to Devices or Instruments for Indicating the Rate of Ascent or Descent of Aircraft. - Google Patents

Abstract

130,356. Short, H. O. Jan. 26, 1918. Differential speed indicators.-Apparatus for indicating the rate of ascent or descent of aircraft comprises a hand 2, moving, in accordance with the consequent variations in atmospheric pressure, over a dial 1 graduated in thousands of feet, combined with a co-axially mounted hand 11 which is driven through change gearing from a clock, the gearing being adjusted until the two hands rotate together. Adjustment of the gearing moves a graduated ring 26 past a fixed pointer 28, the ring being marked to show rate of ascent &c in hundreds of feet per minute. Movement of the dial 1 to set the pointer 2 to zero is effected through a milled head 9, a pinion on which engages teeth on the circumference of the dial. A longitudinally-movable milled head 14 is provided to set the hand 11 or wind the clock. Rotation of the hand 2 is effected by a vacuum chamber 3 through link connexions and a cord 6 passing over a drum 7 on the shaft of the hand. The variable gear comprises a roller 21 mounted to slide between disks 18, 19 secured respectively on a clock-driven shaft 17 and on the axle of the hand 11, movement of the roller being effected by a screw 24 engaging a thread in the interior of the shaft 22 carrying the roller. The shaft 24 is driven through bevel-gearing from a shaft 32, a pinion 31 on which is engaged by internal teeth on the ring 26 rotated by a pinion on a milled head 29. By arranging the disk 18 so that the roller is able to pass across the centre thereof, the speed of descent may be indicated.