Positioning arrangement, especially adjusting the feed stroke of a tool carrier in a machine tool

Claim 1

A positioning arrangement, especially for adjusting the feed stroke of a tool carrier of a machine tool, comprising a housing adapted to be connected at one end thereof to the tool carrier and being provided at an end opposite said one end with a first internal gear; tool spindle means comprisng an operating member having an axis and being mounted in said housing turnably about said axis and immovably in axial direction, said operating member having an end portion located outside said housing and axially spaced from said opposite end thereof and having in the region of said opposite end of said housing a portion eccentrically arranged with respect to said axis, and a positioning spindle operatively connected to said operating member axially movable with respect thereto during turning of said operating member about said axis, said positioning spindle projecting with an end portion thereof beyond said one end of said housing and the tool carrier connected thereto; first scale means for fine adjustment of said positioning spindle on the circumferential surface oF said end portion of said operating member; a scale ring coaxial with said axis and adjacent said opposite end of said housing, said scale ring being provided with a second internal gear; second scale means for rough adjustment of said positioning spindle provided on the outer peripheral surface of said scale ring; a position ring coaxial with said axis between said scale ring and said end portion of said operating member and provided with a third internal gear; a position mark on the outer peripheral surface of said position ring; a single gear ring about said eccentric portion of said operating member in frictional engagement with the peripheral surface thereof to be rotated about its axis during rotation of said operating member, said gear ring having teeth meshing with the teeth of said first, said second and said third internal gear, said first and said third internal gear having an equal number of teeth and the number of teeth on said second internal gear differs from that of said first and second internal gears so that during turning of said operating member about its axis said position ring will remain stationary while said scale ring will be rotated in dependence on the difference of the number of teeth on said first and said second internal gears.