Vacuum operated stepping motor - has double magnetic valve unit controlling evacuation and re-pressurisation incorporated in vacuum chamber

摘要

The vacuum-operated stepping motor has a spring biased membrane (5) carrying a setting element (4) and acted on by the vacuum which is controlled via a pair of magnetic valves. The housing of the stepping motor is in two halves (1,2) with the peripheral edge of the membrane (5) clamped between them. The upper half (1) of the motor housing forms a sealed vacuum chamber in conjunction with the membrane (5), containing the double magnetic valve unit (7). Each of the valves is connected to one of two line connections (30,31) incorporated in the upper half (1), for controlling the evacuation and re-pressurisation of the vacuum chamber respectively. The motor is designed for simplicity of operation and low cost.