When the air pressure increases or decreases in chamber a, membrane 1, to which pin b is fastened, is bent outward or inward. Pin b actuates contact lever 2, turninghe about fixed axis A, so that the lever makes contact with either upper terminal 4 or lower terminal 3. The terminals are adjusted to the required pressure by screws c. Terminals 3 and 4 are connected to an electropneumatic device which regulates the air pressure.
$4081$EHP,M$