TUMBLER GEAR MECHANISAM

If you see the diagram of tumbler gear mechanism below, E gear is attached to the spindle and known as

spindle gear. The purpose of this gear is to rotate feed rod and lead screw in clockwise direction. A and B

are tumbler gears and are fitted in a bracket. The lever M placed in the bracket can move upward or

downward.

In the construction of the mechanism, gear D is known as stud gear and is connected to lead screw by

intermediate gears. It has two different positions. For position 1, the lever M is in upward position and

gear A connects with stud gear D and spindle gear E. This arrangement will move carriage towards

headstock. On the other hand, if it is in position 2, lever will be in the horizontal position and gear E will

connect with gear B, then B to A and A to D. With this arrangement, lead screw direction will reverse and

this time, it will move in the anti-clockwise direction and carriage will move towards tailstock.

If we want to give manual feed then lever should be in the middle position which will make sure that the

gears are not engaged.

Given below is a photograph of a machine with tumbler gear