Bellows 1 is connected by turning pair E to bell-cran lever 2 which turns about fixed axis A. Connecting rod 3 is connected by turning pairs B and C to lever 2 and to link 4 which turns about fixed axis D. Rigidly attached to link 4 is hand a of the instrument. When the pressure changes inside bellows 1 it is either contracted or stretched axially. This motion is indicated by hand a on scale b.
$4057$EHP,M$