Electronic two-speed chess timer

摘要

The chess timer consists of an electronic part to generate clock pulses which drive the mechanical parts of the timer. A quartz pulse generator and two resettable counters can be switched between two clock pulse speeds, normal and 5- or 10-fold speed, to drive the timer mechanisms. A slip coupling to the hour and minute hands allows the timer to be set without moving the second hand. The timer has two buttons on top of the housing, for starting and stopping alternate counters, a third for stopping both, and a switch for normal and fast speed. Second and minute hands are synchronised such as to provide timing with second accuracy.