GB129466A - Improvements in and relating to Speed Indicators. - Google Patents

Abstract

129,466. Japy, A. P. July 19, 1918. Periodic counter and like speed indicators.-An increment proportional to that to be measured is conveyed to the pointer through a planet pinion carried by a sleeve, upon which is mounted loosely a brake drum in gear with the planet wheel, and which has attached to it a second brake drum transmitting motion to a third brake drum carrying the pointer. The wheel 1, Fig. 1, loose on the shaft x is driven proportionately to the vehicle &c., the speed of which it is desired to measure. It gears with a planet pinion 2 carried by a sleeve also loose in the shaft x and in one with the drum 7. A drum 5 mounted loosely on the sleeve gears at 4 with the wheel 2, while a drum 10 carrying the pointer 12 is loose on the shaft x and is driven by a lug 9 on the drum 7 engaging a lug 11 on the drum 10. Both these drums 7, 10 have spiral springs which tend to return them to zero, a position defined by a stop not shown. The brakes are one-way band brakes operated by cams. The cams for operating the brakes are driven in any usual way for instance from a shaft driven at a constant speed. The cycle of operations is as follows. The drum 5 is held and the drive passes through the sleeve to the drum 7 which is free. The drum 10 meanwhile is locked by its brake and the pointer indicates the speed during the last period. If now the lug on the drum 7 catches up the lug on the drum 10, the pointer is moved to register increased speed. At the close of the interval, the drum 7 is held and drums 5 and 10 released, the drum 10 taking up a position defined by the lug on the drum 7, when it is again held by its brake, and the drum 7 released,