US 4,750,272 A · Tool measuring device employing gap width detection

Abstract

A tool measuring apparatus for a machine tool is provided with a plunger (16) mounted to move along an axis (22) to vary the spacing between the end of the plunger and an inductive element (26) of an inductive displacement measuring device (24). Device (24) generates a signal V.sub.y which varies as a function of the spacing between the plunger (16) and device (24). Spindle (14), engaging a tool (12), is moved to a position M located a known distance from inductive element (26). As the spindle is moved to position M, tool (12) engages plunger 16 and moves the plunger to decrease the spacing between the plunger and the element (26) to a value S.sub.3, corresponding to an unknown length d of tool (12). Levels of V.sub.y corresponding to spacing S.sub.3 and to S.sub.2, representing a known nominal value N of tool length, are coupled to a processor 32 and a control 30 to determine tool offset e, i.e., the difference between actual length d and nominal length N.

Claims11

Dependent claims

In a machine tool, apparatus for measuring a selected parameter of a cutting tool engaged by a tool engagement device which is selectively movable and locatable at a first reference position, said tool selectively moving relative to said first reference position in response to operation of said engagement device, said apparatus comprising:

a frame proximate to said first reference position;
means mounted on said frame for generating a measurement signal;
a plunger;
means for supporting said plunger for movement along a path of travel relative to said signal generating means, and for mounting said plunger to receive a force from said moving tool to position said plunger in spaced apart relationship with said signal generating means across a gap having a width representative of said selected tool parameter;
and
said signal generating means includes means for electrically coupling said plunger and said signal generating means across said gap to vary said measurement signal as a function of said gap width, so that said measurement signal varies as a function of said selected tool parameter.

3 more elements

A method for measuring a selected parameter of a cutting tool engaged by a tool engagement device comprising the steps of:

mounting a device for generating a measurement signal at a specified position;
supporting a plunger for movement along a path of travel toward and away from said signal generating means;
selectively moving said engagement device proximate to said signal generating means;
coupling motion of said moving engagement device to said plunger through said tool to move said plunger into spaced apart relationship with said signal generating device across a gap having a width representing the value of said selected tool parameter;
and
electrically coupling said plunger and said signal generating device across said gap to vary said measurement signal as a function of said gap width and thereby as a function of said selected tool parameter.

3 more elements

Dependencies are inferred from the claim text.

Tool measuring device employing gap width detection

Life of this patent

Tool measuring device employing gap width detection

Life of this patent

Abstract

Claims11