GB362795A - Improvements in speed measuring apparatus - Google Patents

Abstract

362,795. Periodic counter speedometers. HASLER AKT.-GES., VORM. TELEGRAPHENWERKST€TTE VON G. HASLER, 50, Schwarztorstrasse, Berne, Switzerland. March 5, 1931, No. 6874. Convention date, March 12, 1930. [Class 106 (iii).] A periodic-counter type speedometer is constructed so as to avoid backlash at the initial position of the measuring wheel and comprises a measuring wheel 16 driven by the pinion 15 mounted on the toothed wheel 13 rotated by the fine toothed wheel 10 having secured to it the toothed wheel 9 which is rotated by the toothed wheel 12 driven from the rotating shaft the speed of which is required and which is mounted on the lever 7 to be periodically disengaged from the wheel 13 through the lever 7 periodically engaging a cam 4 on the spindle 1 time-driven by gear wheels 2, 3 from a main spring. The spindle 1 has also fixed to it a cam 5 which periodically actuates the lever 8 and pawl 25 to control the looking of the wheel 13 and thus the measuring wheel 16. When the wheel 10 is disengaged from the wheel 13 and the wheel 13 is unlocked, the wheel 13 and measuring wheel 16 return to an initial position under the action of the spring 17 and backlash is avoided by that initial position being defined by a blank part 18 in the toothed rim of the measuring wheel 16 contacting with the teeth of the pinion 15 to prevent further motion. The rotation of the measuring wheel is transmitted to a pointer spindle 23 through pins 19, 20 and gear wheels 21, 22 which are returned to an initial position by the spiral spring 24. It is stated that the mechanism described stabilizes the pointer without the use of a stabilizing device which affects the accuracy of the instrument.