| 摘要 |
PURPOSE:To obtain an abacus provided with a timer, by which practice can be executed easily, by turning on a start switch of the timer by a connecting lever interlocked with a one-touch key, when the abacus is calculated anew by operating said key. CONSTITUTION:When an abacus is not in a state of calculating anew, a connecting lever 2 is in a solid position. In this case, a lever 6a of a microswitch 6 is not engaged with the lever 2, therefore, the switch 6 is in a nonconductive state. When the abacus is set to a state of calculating anew, the lever 2 moves to a dotted line position 2'. Therefore, the lever 6a of the switch 6 moves to the dotted line position, and becomes a conductive state. As a result, a timer starts. In this way, a one-touch key of the abacus is interlocked with a start switch of the timer and is operated, therefore, by only depressing a stop switch after a calculation is ended, the time extending from a state of calculating anew to the end of the calculation can be measured automatically, and practice of the abacus is executed easily. |
