Back lash eliminating device - between meshing gears of measuring instrument has second gear wheel coupled to first via spring

摘要

The backlash eliminating, record, gear wheel (6) is of equal size to the first gear wheel (4), both wheels meshing with a further gear wheel of the transmission. The second wheel is coaxial with, and rotatable relative to, the first. The spring is connected to the two gear wheels such that it tends to rotate them in opposite directions. The spring may be a spiral spring whose internal end is fixed to the hub of the second wheel whilst its external end is secured to a lever which is pivotable relative to the first wheel such that the external end can move along a circular arc intersecting the common axis of the two gear wheels.