Patent US5534836A successfully refreshed from Google Patents.
Patent EP0178780A2 successfully refreshed from Google Patents.
EP0178780A2
Expired / Lapsed
EP
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Shaft coupling displacement monitoring
Assignee: Flexibox Ltd
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Filing: 1985-09-12
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Granted: —
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Expires: 2005-09-12
Abstract
Abstract A shaft misalignment monitoring system comprising a coil disposable on one side of a coupling connecting two co-rotating shafts and a ferromagnetic rod disposable on the other side of the coupling, the rod being so positioned within the confines of the coil that misalignment of the shafts alters the relative disposition of the rod and coil so as to affect the inductance of the coil, the coil forming part of an alternating current circuit an operating parameter of which is variable in dependence upon the inductance of the coil and which variable operating parameter is monitored to give an indication of the position of the rod with respect to the coil and hence of the degree of misalignment of the shafts.
Inventors
- 👤 John D. Britton
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:08
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/30; G01B7/31
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
121 words
A shaft misalignment monitoring system comprising a coil disposable on one side of a coupling, connecting two co-rotating shafts and a ferromagnetic rod disposable on the other side of the coupling, the rod being so positioned within the confines of the coil that misalignment of the shafts alters the relative disposition of the rod and coil so as to affect the inductance of the coil, the coil forming part of an alternating current circuit an operating parameter of which is variable in dependence upon the inductance of the coil and which variable operating parameter is monitored to give an indication of the position of the rod with respect to the coil and hence of the degree of misalignment of the shafts.
Claim 2
Dependent Claim
121 words
A shaft misalignment monitoring system comprising a coil disposable on one side of a coupling, connecting two co-rotating shafts and a ferromagnetic rod disposable on the other side of the coupling, the rod being so positioned within the confines of the coil that misalignment of the shafts alters the relative disposition of the rod and coil so as to affect the inductance of the coil, the coil forming part of an alternating current circuit an operating parameter of which is variable in dependence upon the inductance of the coil and which variable operating parameter is monitored to give an indication of the position of the rod with respect to the coil and hence of the degree of misalignment of the shafts.
Claim 3
Dependent Claim
30 words
A system as claimed in claim 1, wherein the alternating current circuit is an oscillating circuit and the variable operating parameter is the frequency of oscillation of the oscillating circuit.
Claim 4
Dependent Claim
17 words
A system as claimed in claim 2, in which said oscillating circuit is a first Colpitts oscillator.
Claim 5
Dependent Claim
42 words
A system as claimed in claim 2 or 3, in which the variable frequency of said oscillating circuit is mixed with a reference frequency to provide a signal including a resultant frequency representative of the difference between the variable and reference frequencies.
Claim 6
Dependent Claim
90 words
A system as claimed in claim 4, in which the resultant frequency is arranged to amplitude modulate a driven signal generated in a secondary winding of a rotary transformer by a primary winding of said transformer, said resultant frequency being detectable in a driving signal applied to the primary winding through reflected impedance changes from the secondary winding and being filtered from said driving signal to provide said indication of the position of the rod with respect to the coil and hence of the degree of misalignment of the shafts.
Claim 7
Independent Claim
59 words
A system as claimed in any one of claims 2 to 5, in which said variable frequency is employed to give an indication of the angular misalignment between the shafts by noting the change in said variable frequency per revolution and of the axial misalignment between the shafts by noting the average level of said variable frequency per revolution.
Claim 8
Dependent Claim
48 words
A system as claimed in claim 6, in which a positional reference probe is arranged to provide a position signal from which the rotational position of the shafts at a given moment can be determined and from which the angular direction of said angular misalignment can be established.
Claim 9
Dependent Claim
51 words
A system as claimed in claim 5 and 6, in which said driving signal is applied to a frequency to voltage converter the output of which is filtered to provide a first signal representative of the degree of angular misalignment and a second signal representative of the degree of axial misalignment.
Claim 10
Dependent Claim
32 words
A system as claimed in claim 7 and 8 in which the position signal is phased with said first signal to determine the angular position of any angular misalignment between the shafts.
Claim 11
Dependent Claim
32 words
A system as claimed in claim 4 and or any of claims 5 to 9 when dependent on claim 4 in which the reference signal is provided by a second Colpitts oscillator.
Claim 12
Dependent Claim
50 words
A system as Claimed in claim 4 or any of claims 5 to 10 when dependent on claim 4, in which said variable frequency is in the range 130 to 170 KHz, and said reference frequency is about 10 KH z larger than the maximum value for said variable frequency.
Claim 13
Independent Claim
24 words
A system as claimed in claims 5 and 11 in which said driving signal has a frequency in the range 400 to 1000 KHz.
Claim 14
Dependent Claim
32 words
A system according to claim 1, wherein the said operating parameter of the alternating current circuit is a voltage the magnitude of which varies in dependence upon the inductance of the coil.
Claim 15
Dependent Claim
40 words
A system according to claim 13, wherein the alternating current circuit comprises a further coil mounted on the said one side of the coupling and connected to the said coil, and a stator coil magnetically coupled to the further coil.
Claim 16
Dependent Claim
40 words
A system according to claim 14, wherein the further coil is annular and arranged around the periphery of the said one side of the coupling, and the stator coil is annular and arranged around but spaced from the further coil.
Claim 17
Dependent Claim
34 words
A system according to claim 15, wherein the stator coil is connected in one arm on a Wheatstone bridge supplied with an alternating current signal, the bridge output being the said variable operating parameter.
Claim 18
Dependent Claim
26 words
A system according to claim 16, wherein a phase detector is provided to monitor the phase difference between the bridge output and the alternating current signal.
Claim 19
Dependent Claim
15 words
A shaft misalignment monitoring system substantially as hereinbefore described with reference to the accompanying drawings.
Claim 20
Dependent Claim
15 words
A shaft misalignment monitoring system substantially as hereinbefore described with reference to the accompanying drawings.
References Cited (Backward Citations)
No citation records indexed.
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