Method and means for detecting the clogging of a grinding wheel or the like

Claim 1

In a method of continuously detecting the degree of clogging of the working surface of a rotary grinding member with particles of electrically conducting material removed from the work being ground, the steps of: supplying an alternating current of selected high frequency to an inspecting element having the characteristics of generating an alternating flux field and having a variable reactance, positioning said inspecting element close to the working surface of said rotary grinding element while the latter is rotating to apply said flux field to particles of electrically conducting material lodged on said working surface and thereby produce counterelectromotive force which varies the reactance of said inspecting element, said counterelectromotive force and hence the reactance of said inspecting element varying with the incremental quantities of said conducting material distributed at random on the periphery of said grinding member, continuously detecting the reactance of said inspecting element to produce a train of signals corresponding in amplitude to the varying reactance of said inspecting element and hence to the quantities of conductive material on the working surface of said grinding member, integrating said signals during each successive periods of uniform selected length, and comparing the integrated signal to a selected standard to produce an output signal when the integrated signal at least equals said standard.

Claim 5

A system for continuously detecting the degree of clogging of the working surface of a rotary grinding member with particles of electrically conducting material removed from the work being ground, comprising: an inspecting element positioned close to the working surface of said grinding member, an oscillator circuit supplying alternating current of selected high frequency to said inspecting element, said inspecting element comprising means for generating a magnetic flux when supplied with alternating current from said oscillator circuit and thereby inducing eddy currents in particles of conducting material on the working surface of said rotary grinding member as they pass said inspecting element, said eddy currents producing a counterelectromotive force to vary the inductance of said inspecting element in accordance with incremental quantities of said conductive material distributed at random around the periphery of said grinding member, circuit means for continuously detecting the reactance of said inspecting element and producing a train of signals corresponding in amplitude to the varying reactance of said inspecting element and hence to the quantities of conductive material on the working surface of said grinding member, circuit means for integrating said signals during each of successive periods of time, timing means connected with said integrating circuit means and supplying timing signals to said integrating circuit means to define said successive time periods, comparison circuit means for comparing the level of integrated signals received from said integrating circuit means with a selected standard and producing an output signal when said integrated signal at least equals said standard, and circuit means for supplying said standard to said comparison circuit means.

Claim 6

A system for continuously detecting the degree of clogging of the working surface of a rotary grinding member with particles of electrically conducting material removed from the work being ground, comprising: an inspecting element positioned close to the working surface of said grinding member, an oscillator circuit supplying alternating current of selected high frequency to said inspecting element, said inspecting element comprising means for generating a magnetic flux when supplied with alternating current from said oscillator circuit and thereby inducing eddy currents in particles of conducting material on the working surface of said rotary grinding member as they pass said inspecting element, said eddy currents producing a counterelectromotive force to vary the inductance of said inspecting element in accordance with incremental quantities of said conductive material distributed at random around the periphery of said grinding member, circuit means for continuously detecting the reactance of said inspecting element and producing a train of signals corresponding in amplitude to the varying reactance of said inspecting element and hence to the quantities of conductive material on the working surface of said grinding member, circuit means for integrating said signals during each of successive periods of time, timing means connected with said integrating circuit means and supplying timing signals to said integrating circuit means to define said successive time periods, comparison circuit means for comparing the level of integrated signals received from said integrating circuit means with a selected standard and producing an output signal when said integrated signal at least equals said standard, and circuit means for supplying said standard to said comparison circuit means.