Method and apparatus for detecting timing belt damage using inductive link coupling
First Claim
1. Apparatus for monitoring a change of condition in a drive belt, said apparatus comprisinga first inductance coil;
- a second inductance coil;
an electrically conductive loop associated with said drive belt for motion therewith, said conductive loop exhibiting an impedance change indicative of said change of condition, and forming a mutual inductive link coupling between said first and second inductance coils; and
a detector coupled to at least one of said first and second inductance coils for indicating a change in said mutual inductive link coupling caused by said impedance change.
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Abstract
A drive belt, such as a toothed belt such as for an automotive or other engine timing belt or a V-belt for driving machinery comprises a belt with a thin conductive wire or strip embedded in the belt material in the form of a closed loop. Such a wire tends to exhibit damage typically some time before belt failure is imminent. First and second coils are coupled by mutual inductance to the closed loop formed by embedded wire which functions as a link coupling between the first and second coils. In one embodiment, an ac current is passed through the first coil and the current in the second coil is monitored for a drop in amplitude when the embedded wire is broken and the closed loop is interrupted.
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Citations
21 Claims
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1. Apparatus for monitoring a change of condition in a drive belt, said apparatus comprising
a first inductance coil; -
a second inductance coil;
an electrically conductive loop associated with said drive belt for motion therewith, said conductive loop exhibiting an impedance change indicative of said change of condition, and forming a mutual inductive link coupling between said first and second inductance coils; and
a detector coupled to at least one of said first and second inductance coils for indicating a change in said mutual inductive link coupling caused by said impedance change. - View Dependent Claims (2, 3, 4)
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5. Apparatus for monitoring a change of condition in a drive belt, said apparatus comprising
a first inductance coil; -
a source of an alternating current coupled to said first inductance coil;
a second inductance coil;
an electrically conductive loop coupled for movement with said drive belt, said conductive loop exhibiting an impedance change indicative of said change of condition, and forming a mutual inductive link coupling between said first and second inductance coils for inducing an electromotive force in said second inductance coil; and
a detector coupled to said second coil for monitoring a change in said electromotive force in said second coil caused by said impedance change. - View Dependent Claims (6, 7, 8, 9)
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10. Apparatus for monitoring a change of condition in a drive belt by detecting an impedance change in a wire loop at least partially embedded in said drive belt, said wire loop exhibiting an impedance change indicative of said change of condition, said apparatus comprising:
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a first inductance mutually coupled to said wire loop;
a source of an alternating current coupled to said first inductance;
a second inductance mutually coupled to said wire loop such that said wire loop forms a link coupling between said first and second inductances; and
a detector coupled to said second inductance for monitoring a change in induced voltage or electromotive force in said second inductance caused by said impedance change. - View Dependent Claims (11, 12, 13, 14)
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15. Apparatus for monitoring a change of condition in a drive belt, said apparatus comprising:
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means for associating an electrically conductive loop for movement with said drive belt such that said electrically conductive loop exhibits an impedance change indicative of said change of condition;
means for mutually inductively coupling a first inductance coil and said conductive loop;
means for mutually inductively coupling a second inductance coil and said conductive loop;
means for passing an alternating current through a first inductance coil; and
means for detecting a change in electromotive force in said second coil caused by said impedance change. - View Dependent Claims (16, 17, 18)
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19. A method for monitoring a change of condition in a drive belt, said method comprising the steps of:
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associating an electrically conductive loop for movement with said drive belt such that said electrically conductive loop exhibits an impedance change indicative of said change of condition;
mutually inductively coupling a first inductance coil and said conductive loop;
mutually inductively coupling a second inductance coil and said conductive loop, such that said conductive loop forms a link coupling between said first and second inductance coils;
passing an alternating current through a first inductance coil; and
detecting a change in electromotive force in said second coil caused by said impedance change. - View Dependent Claims (20)
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21. Apparatus for monitoring a change of condition in a drive belt, comprising:
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means for providing a closed loop conductive path along the length of said drive belt such that said conductive path exhibits an impedance change indicative of said change of condition;
means for providing a first self-inductance and for providing mutual inductance coupling between said means for providing a first self-inductance and said means for providing a closed loop conductive path;
means for providing a second self-inductance and for providing mutual inductance coupling between said means for providing a first self-inductance and said means for providing a closed loop conductive path;
means for applying an alternating current to said means for providing a first self-inductance;
means for detecting electromotive force induced by said current in said means for providing a second self-inductance; and
means for detecting a predetermined change in said electromotive force caused by said impedance change.
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Specification