Material sensor
First Claim
Patent Images
1. Material sensor comprising:
- a) deflectable means for contacting material woven through the sensor and being deflectable by the material;
b) piezoelectric film means operatively coupled to the deflectable means for providing signals in response to deflections of the deflectable means, the signal being indicative of a condition of the material, wherein the deflectable means undergoes rapid and sudden deflection upon the occurrence of a broken material and the piezoelectric films develops charge thereon as a result of said rapid and sudden deflection; and
c) circuit means coupled to the piezoelectric film means, and wherein the piezoelectric film means has an intrinsic capacitance C, and the circuit means comprises a resistor R coupled in RC relationship with the piezoelectric film means to define a discharge path having an RC time constant, the charge discharging through the discharge path, the RC time constant being selected to substantially minimize any substantial signal of opposite polarity to the polarity of the developed charge.
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Abstract
A material sensor employs deflectable means and piezoelectric film means for providing signals indicative of a material condition.
42 Citations
42 Claims
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1. Material sensor comprising:
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a) deflectable means for contacting material woven through the sensor and being deflectable by the material; b) piezoelectric film means operatively coupled to the deflectable means for providing signals in response to deflections of the deflectable means, the signal being indicative of a condition of the material, wherein the deflectable means undergoes rapid and sudden deflection upon the occurrence of a broken material and the piezoelectric films develops charge thereon as a result of said rapid and sudden deflection; and c) circuit means coupled to the piezoelectric film means, and wherein the piezoelectric film means has an intrinsic capacitance C, and the circuit means comprises a resistor R coupled in RC relationship with the piezoelectric film means to define a discharge path having an RC time constant, the charge discharging through the discharge path, the RC time constant being selected to substantially minimize any substantial signal of opposite polarity to the polarity of the developed charge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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13. A material sensor comprising:
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a) deflectable means for contacting material woven through the sensor and being deflectable by the material, wherein the deflectable means comprises a cantilevered beam biased so that a free end thereof urges against the material; b) piezoelectric film means operatively coupled to the deflectable means for providing signals in response to deflections of the deflectable means, the signal being indicative of a condition of the material; and c) a beam bracket fixed to a body of the sensor and having a pair of tabs projecting over a portion of the beam so as to define a stop for the free end of the beam. - View Dependent Claims (16)
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18. A material sensor, comprising:
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a) deflectable means for contacting material woven through the sensor and being deflectable by the material, wherein the deflectable means comprises a cantilevered beam biased so that a free end thereof urges against the material, wherein the cantilevered beam comprises a strip of spring steel; b) piezoelectric film means operatively coupled to the deflectable means for providing signals in response to deflections of the deflectable means, the signal being indicative of a condition of the material, wherein the piezoelectric film means is affixed to the spring steel; and c) a rod disposed between an upper side of the beam and the material and defining a stop of the free end of the beam, wherein a portion of the beam opposite the free end is fixed to a bracket, the bracket being adjustable to alter a contact point of the free end of the beam against the stop so as to adjust a preload condition of the beam.
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28. Apparatus for providing an indication of material tension and material breakage comprising:
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a) guide means defining a substantially straight path for material to pass through a body; b) a cantilever beam disposed within the body and having a free end biased to urge against material passing through the body and being deflectable in response to changes in material tension; c) a strip of piezoelectric polymer film affixed to the cantilever beam and providing electrical signals in response to deflections of the cantilever beam, wherein the beam undergoes rapid and sudden deflection upon the occurrence of a broken material and the polymer film develops charge thereon as a result; d) circuit means for processing the signals provided by the film, wherein the piezoelectric film means has an intrinsic capacitance C, and the circuit means comprises a resistor R coupled in RC relationship with the piezoelectric film means to define a discharge path having an RC time constant, the charge discharging through the discharge path, the RC time constant being selected to substantially minimize any substantial signal of opposite polarity to the polarity of the developed charge; and the circuit means providing an output having a magnitude indicative of material tension and that assumes a defined particular state in the absence of material tension, the defined state being indicative of a material breakage. - View Dependent Claims (29, 32, 33, 34, 35)
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30. Apparatus for providing an indication of material tension and material breakage comprising:
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a) guide means defining a substantially straight path for material to pass through a body; b) a cantilever beam disposed within the body and having a free end biased to urge against material passing through the body and being deflectable in response to changes in material tension; c) a strip of piezoelectric polymer film affixed to the cantilever beam and providing electrical signals in response to defections of the cantilever beam; d) circuit means for processing the signals provided by the film, the circuit means providing an output having a magnitude indicative of material tension and that assumes a defined particular state in the absence of material tension, the defined state being indicative of a material breakage; e) a stop disposed within the body, the cantilever beam urging against the stop in the body in the absence of material tension, wherein the stop comprises a beam bracket fixed to the body and having a pair of tabs projecting over the free end of the cantilever beam.
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31. Apparatus for providing an indication of material tension and material breakage comprising:
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a) guide means defining a substantially straight path for material to pass through a body; b) a cantilever beam disposed within the body and having a free end biased to urge against material passing through the body and being deflectable in response to changes in material tension; c) a strip of piezoelectric polymer film affixed to the cantilever beam and providing electrical signals in response to deflections of the cantilever beam; d) circuit means for processing the signals provided by the film, the circuit means providing an output having a magnitude indicative of material tension and that assumes a defined particular state in the absence of material tension, the defined state being indicative of a material breakage; e) a stop disposed within the body, the cantilever beam urging against the stop in the body in the absence of material tension, wherein the stop comprises a rod disposed between an upper side of the beam and the path, a portion of the beam opposite the free end being fixed to an adjustable bracket, the bracket being adjustable to alter a point of contact of the free end against the stop and alter a preload condition of the beam.
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36. Apparatus for providing an indication of material tension and material breakage comprising:
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a) first guide means defining a substantially straight path for material to pass through a body; b) a cantilever beam disposed within the body and having second guide means disposed on a free end thereof for material to pass therethrough, the first guide means being arranged to cause the material to fictionally engage the second guide means, the beam vibrating when material passes through the second guide means and deflecting in response to changes in material tension; c) a strip of piezoelectric polymer film affixed to the cantilever beam and providing electrical signals in response to vibrations and deflections of the cantilever beam, wherein the beam undergoes rapid and sudden deflection upon the occurrence of a broken material and the polymer film develops charge thereon as a result; and d) circuit means for processing the signals provided by the piezoelectric film, the circuit means providing outputs indicative of material tension and material breakage, wherein the piezoelectric film means has an intrinsic capacitance C, and the circuit means comprises a resistor R coupled in RC relationship with the piezoelectric film means to define a discharge path having an RC time constant, the charge discharging through the discharge path, the RC time constant being selected to substantially minimize any substantial signal of opposite polarity to the polarity of the developed charge. - View Dependent Claims (37, 38, 39)
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- 40. Apparatus for providing an indication of material breakage comprising a strip of piezoelectric polymer film laminated with a resilient abrasion resistance material and cantilevered with a free end adapted to contact passing material to be monitored for breakage and being deflectable in response to changes in material tension but returning to a rest position upon the occurrence of a material breakage, the piezoelectric film providing signals in the presence of passing material but not signals after the occurrence of a material break, wherein the piezoelectric film undergoes rapid and sudden deflection upon the occurrence of a broken material and develops charge thereon as a result wherein the piezoelectric film has an intrinsic capacitance C and circuit means for processing the signals provided by the film the circuit means comprising a resistor R coupled in RC relationship with the piezoelectric film to define a discharge path having an RC time constant, the charge discharging through the discharge path, the RC time constant being selected to substantially minimize any substantial signal of opposite polarity to the polarity of the developed charge.
Specification