Upward motion of measuring spindle 1 turns lever 2 counterclockwise about fixed axis A. Tip a of lever 2 moves gear rack 3 to the left. This motion is transmitted by gears 4 and 5 to pinion 6 with hand b. Spring 7 eliminates backlash in the gearing. Spring 8 returns rack 3 to its initial position and holds rack 3, lever 2 and spindle 1 in contact with one another. It also produces the contact pressure in measuring.
$1779$GL,M$