GB191125106A - Improvements in Speed Indicators. - Google Patents

Abstract

25,106. Low, A. M. Nov. 11. Differential speed indicators.-In apparatus for indicating the average speed of a vehicle &c. during the interval that has elapsed since the instrument was re-set, the index-hand is adapted to be urged in one direction by a clock and in the other by the vehicle, both forces being applied through spiral springs and being proportional to the time and to the distance respectively. Motion from the clock is communicated to the shaft d of the index-hand through a gear-wheel h, a clutch i, and a spiral spring k, of which one end is secured to the clutch i and the other to the shaft d. A vehicle-driven shaft m tends to produce rotation in the opposite direction through worm gearing, a clutch s, and a spiral spring u. The shaft d is mounted in a bearing e carried by a bracket f, endlong movement of the shaft being prevented so that, on a given torsion being attained in one or both of the springs u, k, with corresponding axial shortening, the clutch parts are separated against the pressure of a spring w. The dial is graduated to correspond with the period over which the observation is to be taken, a number of circles corresponding thereto being marked on the dial, as shown in Fig. 3, and numbered 1 ... 6. The minimum speed indicated is ten miles per hour, a stop b<1> preventing movement of the pointer below that point. From the line 1 is drawn a series of lines corresponding to the speeds 10, 15, 20, 25, 30, and 50 miles per hour, the speed at any time being determined by the position of the pointer with regard to the time and the speed curves. A pivoted fork v is provided to disengage the clutches at the end of the period.