Upon a change in temperature of the medium in which thermal bulb 1 is immersed, the pressure of the liquid filling the thermal bulb and Bourdon tube 2 changes. Tube 2 is deformed and the motion of its free end turns three-arm lever 3 about fixed axis A. Segment gear b of the three-arm lever meshes with pinion 4, which is rigidly attached to hand a and turns about fixed axis B. Hand a indicates the reading of the instrument on scale c. At the same time, lever 3 operates pen d which records the temperature on a chart paper fastened to rotating drum 7. Motion is transmitted to pen d, rigidly mounted on lever 6 which turns about fixed axis C, through intermediate link 5. Link 5 is connected by turning pairs E and F to levers 3 and 6.
$4067$EHP,M$