Patent US2655195A successfully refreshed from Google Patents.
EP0254445A1
Expired / Lapsed
EP
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A transducer
Assignee: Individual
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Filing: 1987-07-03
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Granted: —
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Expires: 2007-07-03
Abstract
Abstract A passive electrically operable monitoring means has an inherent resistance and a characteristic capacitance and inductance only, so that the monitoring means has a predetermined natural frequency of oscillation. Variations in a physical parameter being monitored by the monitoring means will cause the characteristic capacitance and/or inductance to vary thereby varying the natural frequency of oscillation of the monitoring means. A transducer includes an excitation means (32) for exciting the monitoring means and a sensing means for sensing the natural frequency of oscillation of the monitoring means. The excitation means (32) includes a pulse generating means for exciting the monitoring means with a string of pulses having a repetition rate suitably lower than the natural frequency of oscillation of the monitoring means so that damped oscillations occur in the monitoring means.
Inventors
- 👤 Frans Johannes Kruger
- 👤 Philip Elliot Galasko
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 17:58
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/02; G01N29/036; B; B60; B60C; B60C23/00; B60C23/02; B60C23/04; B60C23/0491; B60C23/0493; G01D; G01D5/00; G01D5/12; G01D5/243; G01K; G01K7/00; G01K7/34; G01L; G01L17/00; G01L9/00; G01L9/0001; G01L9/0008; G01N2291/00; G01N2291/02; G01N2291/025; G01N2291/0256
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
62 words
A passive electrically operable monitoring means for use with a transducer for monitoring a physical parameter, the monitoring means having an inherent resistance and a characteristic capacitance and inductance, a selected one of the characteristic capacitance and inductance being variable such that the monitoring means has a natural frequency of oscillation that varies in accordance with variations in the parameter being monitored.
Claim 2
Dependent Claim
62 words
A passive electrically operable monitoring means for use with a transducer for monitoring a physical parameter, the monitoring means having an inherent resistance and a characteristic capacitance and inductance, a selected one of the characteristic capacitance and inductance being variable such that the monitoring means has a natural frequency of oscillation that varies in accordance with variations in the parameter being monitored.
Claim 3
Dependent Claim
29 words
The monitoring means as claimed in Claim 1, which includes a length of conducting wire wound into a coil with spaces being provided between adjacent turns of the coil.
Claim 4
Dependent Claim
19 words
The monitoring means as claimed in Claim 2 in which the turns are resiliently arranged relative to one another.
Claim 5
Dependent Claim
69 words
The monitoring means as claimed in Claim 3 which includes a resiliently flexible web arranged between the turns of the coil, with the turns being secured to the web so that, in use, as the web flexes under the effect of pressure or force being monitored, the spacing between the turns varies thereby varying the characteristic inductance or capacitance of the coil, and hence its natural frequency of oscillation.
Claim 6
Dependent Claim
54 words
The monitoring means as claimed in Claim 2 which includes a conduit defining means which defines a conduit for introducing a gas into proximity with the coil, so that as the temperature or humidity of the gas varies, the characteristic inductance or capacitance varies, thereby varying the natural frequency of oscillation of the coil.
Claim 7
Dependent Claim
42 words
The monitoring means as claimed in Claim 5 in which the conduit defining means includes a length of tube which is coiled with the length of wire of the coil so that the tube is arranged between the turns of the coil.
Claim 8
Dependent Claim
27 words
The monitoring means as claimed in Claim 1 which comprises at least two lengths of spaced conductors arranged in a two-wire transmission line or co-axial cable manner.
Claim 9
Dependent Claim
43 words
The monitoring means as claimed in Claim 7 in which the spacing between the conductors or the effective length thereof is variable to vary the natural frequency of oscillation of the monitoring means when the parameter to be monitored is pressure or force.
Claim 10
Dependent Claim
44 words
The monitoring means as claimed in Claim 7 which includes a conduit defining means for defining a conduit whereby a gas can be introduced into spaces in proximity to the conductors when the parameter to be monitored is temperature or humidity of the gas.
Claim 11
Dependent Claim
45 words
The monitoring means as claimed in Claim 2 which includes a dielectric medium located between the turns of the coil, the permittivity of the dielectric medium being variable in response to variations in pressure or force applied thereto, for varying the natural frequency of oscillation.
Claim 12
Dependent Claim
44 words
The monitoring means as claimed in Claim 7 which includes a dielectric medium located between the lengths of conductors, the permittivity of the dielectric medium being variable in response to variations in pressure or force applied thereto, for varying the natural frequency of oscillation.
Claim 13
Dependent Claim
41 words
A transducer for monitoring a physical parameter, the transducer including a monitoring means as claimed in Claim 1; an energising means for energising the monitoring means; and a sensing means for sensing the natural frequency of oscillation of the monitoring means.
Claim 14
Dependent Claim
48 words
The transducer as claimed in Claim 12 in which the energising means includes an energising coil which is coupled electrically and/or magnetically to the monitoring means in a wireless manner for energising the monitoring means to cause the monitoring means to oscillate at its natural frequency of oscillation.
Claim 15
Dependent Claim
46 words
The transducer as claimed in Claim 13 which includes a pulse generating means for generating a string of pulses at a repetition rate sufficiently lower than the natural frequency of oscillation of the monitoring means so that damped oscillations occur in the monitoring means, in use.
Claim 16
Dependent Claim
30 words
The transducer as claimed in Claim 12, in which the sensing means includes a sensing coil which is electrically and/or magnetically coupled to the monitoring means in a wireless manner.
Claim 17
Dependent Claim
24 words
A tyre which includes a casing; and a monitoring means as claimed in Claim 1 inclusive mounted within and rotatably fast with the casing.
Claim 18
Independent Claim
101 words
A method of monitoring a physical parameter which includes energising a passive electrical monitoring means having a characteristic capacitance and inductance and an inherent resistance so that the monitoring means oscillates at a natural frequency of oscillation; causing the characteristic capacitance or the characteristic inductance to vary in accordance with variations in the parameter being monitored thereby to vary the natural frequency of oscillation of the monitoring means in response to variations in the parameter; and sensing the variations in the natural frequency of oscillation of the monitoring means to provide an indication of the value of the parameter being monitored.
Claim 19
Independent Claim
101 words
A method of monitoring a physical parameter which includes energising a passive electrical monitoring means having a characteristic capacitance and inductance and an inherent resistance so that the monitoring means oscillates at a natural frequency of oscillation; causing the characteristic capacitance or the characteristic inductance to vary in accordance with variations in the parameter being monitored thereby to vary the natural frequency of oscillation of the monitoring means in response to variations in the parameter; and sensing the variations in the natural frequency of oscillation of the monitoring means to provide an indication of the value of the parameter being monitored.
Claim 20
Dependent Claim
82 words
The method as claimed in Claim 17, in which the monitoring means comprises a length of conducting wire wound into a coil to provide a plurality of spaced turns, and in which, when the parameter to be monitored is pressure or force, the method includes varying the spacing between the coils to vary the characteristic capacitance or inductance of the coil, and hence its natural frequency of oscillation, in response to variations in the pressure or force being applied to the coil.
Claim 21
Dependent Claim
90 words
The method as claimed in Claim 17, in which the monitoring means comprises a length of conducting wire wound into a coil to provide a plurality of spaced turns, and in which, when the parameter to be monitored is humidity or temperature of a gas, the method includes introducing the gas into proximity to the turns of the coils so that the characteristic inductance or capacitance of the coil, and hence its natural frequency of oscillation, varies in response to variations in the humidity or the temperature of the gas.
Claim 22
Dependent Claim
54 words
The method as claimed in Claim 19 which includes introducing the gas in proximity to the turns of the coil by means of a conduit defining means, the conduit defining means being wound together with the length of conducting wire so that the conduit defining means is arranged between the turns of the coil.
Claim 23
Dependent Claim
52 words
The method as claimed in Claim 19 in which the monitoring means comprises at least two lengths of conductors which are arranged in a two-wire transmission line or co-axial cable manner, and in which the method includes varying the spacing between the conductors, when the parameter being monitored is pressure or force.
Claim 24
Dependent Claim
61 words
The method as claimed in Claim 17 in which the monitoring means comprises at least two lengths of conductors which are arranged in a two-wire transmission line or co-axial cable manner, and in which the method includes introducing a gas into a space in proximity to the conductors when the parameter being monitored is the temperature or humidity of the gas.
Claim 25
Dependent Claim
68 words
The method as claimed in Claim 17 in which the monitoring means comprises a length of conducting wire wound into a coil to provide a plurality of spaced turns, and in which the method includes, when the parameter being monitored is pressure or force, causing the permittivity or permeability of a medium between the turns to vary, thereby to vary the natural frequency of oscillation of the coil.
Claim 26
Dependent Claim
50 words
The method as claimed in Claim 23 which includes locating a suitable material between the turns, the material being allowed to expand or to be compressed as the force or pressure being monitored , and which is exerted on the material, varies so that the permittivity of the material varies.
Claim 27
Dependent Claim
37 words
The method as claimed in Claim 24 which includes intro ducing a suitable material between the elements in proportion to the force or pressure being monitored, so that the permittivity of the medium between the turns varies.
Claim 28
Dependent Claim
18 words
The method as claimed in Claim 17 which includes energising the monitoring means with a string of pulses.
Claim 29
Dependent Claim
44 words
The method as claimed in Claim 26 which includes energising the monitoring means with a string of pulses which has a repetition rate suitably lower than the natural frequency of oscillation of the monitoring means so that damped oscillations occur in the monitoring means.
References Cited (Backward Citations)
DE3205705A1
Cited
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