Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
197 words
Inductive proximity sensor for detecting an object having electrical conductivity comprising a measuring coil having a front end facing the direction of the object to be detected, a reference member, a reference coil having a front end facing said reference member, said measuring and reference coils being placed on either side of a plane of symmetry and having their respective front ends facing in opposite directions, a block formed from homogeneous magnetic material which partially surrounds both said coils leaving their respective front ends free, an electronic circuit for supplying both said coils with an AC signal, measuring the change in loss resistance and/or self inductance of the measuring coil with respect to that of the reference coil as said object to be detected approaches and determining therefrom the distance or the presence of the object, means for suppress mutual crosstalk between the two said coils, and a separate respective detector circuit for each of said coils coupled together so as to electronically compensate for the effect of changes in properties of the magnetic material and of the measuring coil on the detection distance, wherein each said separate detector is a synchronous detector having its own oscillator.
Claim 2
Dependent Claim
197 words
Inductive proximity sensor for detecting an object having electrical conductivity comprising a measuring coil having a front end facing the direction of the object to be detected, a reference member, a reference coil having a front end facing said reference member, said measuring and reference coils being placed on either side of a plane of symmetry and having their respective front ends facing in opposite directions, a block formed from homogeneous magnetic material which partially surrounds both said coils leaving their respective front ends free, an electronic circuit for supplying both said coils with an AC signal, measuring the change in loss resistance and/or self inductance of the measuring coil with respect to that of the reference coil as said object to be detected approaches and determining therefrom the distance or the presence of the object, means for suppress mutual crosstalk between the two said coils, and a separate respective detector circuit for each of said coils coupled together so as to electronically compensate for the effect of changes in properties of the magnetic material and of the measuring coil on the detection distance, wherein each said separate detector is a synchronous detector having its own oscillator.
Claim 3
Dependent Claim
21 words
Inductive proximity sensor according to claim 1, wherein both oscillators of the synchronous detectors have a frequency offset from each other.
Claim 4
Dependent Claim
52 words
Inductive proximity sensor according to claim 1, wherein the block of homogeneous magnetic material is composed of two sub-blocks of essentially identical, homogeneous magnetic material, which sub-blocks adjoin each other at the plane of symmetry and of which the one sub-block encloses the measuring coil and the other sub-block the reference coil.
Claim 5
Dependent Claim
25 words
Inductive proximity sensor according to claim 1, wherein said screening means comprises a screening ring of conducting material disposed around the block of magnetic material.
Claim 6
Dependent Claim
24 words
Inductive proximity sensor according to claim 4, wherein the screening ring extends over a part of the circumference around the block of magnetic material.
Claim 7
Dependent Claim
24 words
Inductive proximity sensor according to claim 4 wherein the screening ring extends over the width of the circumference around the block of magnetic material.
Claim 8
Dependent Claim
39 words
Inductive proximity sensor according to claim 4, wherein said reference member comprises an extension of the screening ring projecting from the front of the reference coil, as a result of which the function of the reference number is obtained.