Eccentric gearing means

Claim 1

Apparatus for use will a milling machine or the like, said machine including a vernier dial to indicate the small distances a table is moved in said machine, said apparatus comprising: speed reduction gearing means connected to said vernier dial; a coarse dial connected to said speed reduction gearing means for indicating distances substantially larger than said small distances to thereby provide a coarse indication of the total distance said table is moved in said machine; said vernier dial being fixedly and concentrically mounted with respect to the axis of a shaft; said coarse dial being rotatably and concentrically mounted with respect to the axis of said shaft, said coarse dial including a hollow portion and on the inner periphery of said hollow portion a plurality of slots; said speed reduction gearing means including an internal gear disposed within said hollow portion, said internal gear being eccentrically mounted on a support on said vernier dial; and means connected to said internal gear for preventing rotation of said gear with said shaft but permitting eccentric motion of said gear so that at least one of the teeth of said gear acts upon at least one of the said slots at all times whenever said shaft rotates; said means for preventing rotation of said internal gear including universal joint means comprising: a connecting member having a first pair of pins perpendicularly disposed to one side thereof along a first imaginary line and a second pair of pins perpendicularly disposed to the opposite side thereof along a second imaginary line substantially perpendicular to the first imaginary line; a further member fixedly connected to a fixed reference point so that it cannot rotate with said shaft, said further member having a pair of elongated slots for receiving said second pair of pins; and where said internal gear includes a pair of elongated slots for receiving said first pair of pins.