Cylinder 1 is rigidly linked to link 2 and the rod of piston 3 to link 4. The liquid in the cylinder is subject to a pressure which corresponds to the tensile force F applied to links 2 and 4. The liquid enters cylinder 5 and moves piston 6 downward, stretching spring 7. The extension of spring 7 is registered by pin a, mounted on lever 10 which turns about fixed axis A. Hand d indicates the magnitude of force F on scale 9, while pin a plots a graph of the force on chart paper attached to revolving drum 8.
$3929$LHP,M$