Limit switch for downward movement of dentist's chair - is positioned along length of chair and also initiates brief upwards movement

摘要

The chair is of a kind that can be lowered so close to the floor that it is necessary to guard against someone's foot being trapped underneath. The chair is to be fitted with a contact switch extending along the whole of the chair's length. When the switch is operated, it not only halts the chair's downward movement, but initiates a brief upward movement, preferably by causing a capacitor to discharge through the appropriate relay. The level at which the limit switch operates is pref. adjustable with the aid of pendulum bars or a pendulum plate.