| 摘要 |
PURPOSE:To make a measuring instrument small-sized, especially, thin and to enhance the reduction ratio, by using a worm gear. CONSTITUTION:A frequency corresponding to the car velocity generated by a pulse generator 1 is shaped to square waves, and they are counted successively at intervals of a set time, and pulse motor driving pulses whose number is equal to the difference between the current counted value and the just preceding counted value and a normal rotation or reverse rotation signal of a pulse motor 9 are generated. The pulse motor 9 is rotated normally or reversely, and a needle shaft 7 is turned through a spiral spring 6 while following up the rotation of a worm wheel 4, which is rotated in deceleration through a worm 3 connected to the motor rotation shaft, to indicate a measure speed on a dial 11. |
