Method of and apparatus for detecting predicted failure in fluid-pressure system
First Claim
1. A method of predicting a failure in a fluid-pressure system, comprising the steps of:
- establishing first and second thresholds defining a pressure difference as predetermined ratios of a maximum pressure reference level for a fluid under pressure, which maximum pressure reference level is detected by a pressure detecting device;
establishing a third threshold which is lower than said maximum pressure reference level and higher than said first and second thresholds;
supplying an output signal to a driven member while a pressure detecting by said pressure detecting device falls between said first and second thresholds; and
producing an output signal indicative of a predicted failure when a maximum pressure of said fluid under pressure lower than said third threshold is detected by said pressure detecting device.
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Accused Products
Abstract
First and second thresholds are established which define a pressure difference relative to a maximum pressure level for a fluid under pressure, which maximum pressure level is detected by a pressure detecting device, and a third threshold is also established which is lower than the maximum pressure level and higher than the first and second thresholds. While a pressure detected by the pressure detecting device ranges between the first and second thresholds, an output signal is supplied to a drive member. When a pressure lower than the third threshold is detected by the pressure detecting device, an output signal indicative of a predicted failure is produced. The output signal indicative of a predicted failure is produced when a pressure lower than the third threshold is detected a plurality of times by the pressure detecting device.
17 Citations
21 Claims
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1. A method of predicting a failure in a fluid-pressure system, comprising the steps of:
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establishing first and second thresholds defining a pressure difference as predetermined ratios of a maximum pressure reference level for a fluid under pressure, which maximum pressure reference level is detected by a pressure detecting device; establishing a third threshold which is lower than said maximum pressure reference level and higher than said first and second thresholds; supplying an output signal to a driven member while a pressure detecting by said pressure detecting device falls between said first and second thresholds; and producing an output signal indicative of a predicted failure when a maximum pressure of said fluid under pressure lower than said third threshold is detected by said pressure detecting device. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of predicting a failure in a fluid-pressure system, comprising the steps of:
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establishing first and second thresholds defining a pressure difference relative to a maximum pressure level for a fluid under pressure, which maximum pressure level is detected by a pressure detecting device; establishing a third threshold which is lower than said maximum pressure level and higher than said first and second thresholds; supplying an output signal to a driven member while a pressure detected by said pressure detecting device falls between said first and second thresholds; and producing an output signal indicative of a predicted failure when a pressure lower than said third threshold is detected by said pressure detecting device; wherein said output signal indicative of a predicted failure is produced when a pressure lower than said third threshold is detected a plurality of times by said pressure detecting device. - View Dependent Claims (8, 9, 10, 11)
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12. A method of predicting a failure in a fluid-pressure system, comprising the steps of:
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establishing first and second thresholds defining a pressure difference relative to a maximum pressure level for a fluid under pressure, which maximum pressure level is detected by a pressure detecting device; establishing a third threshold which is lower than said maximum pressure level and higher than said first and second thresholds; supplying an output signal to a driven member while a pressure detected by said pressure detecting device falls between said first and second thresholds; and producing an output signal indicative of a predicted failure when a pressure lower than said third threshold is detected by said pressure detecting device; wherein said output signal supplied to the driven member is of a rectangular waveform having a positive-going edge produced when a pressure corresponding to said first threshold is detected and a negative-going edge produced when a pressure corresponding to said second threshold is detected. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An apparatus for predicting a failure in a fluid-pressure system, comprising:
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pressure detecting means for detecting a change in a fluid pressure; an A/D converter for converting a signal indicating a pressure detected by said pressure detecting means into a digital signal; means for transmitting a pressure switch signal corresponding to a pressure difference defined by first and second thresholds relative to a maximum pressure level of the fluid pressure which varies; determining means for comparing said maximum pressure level with a third threshold when said pressure switch signal is transmitted, and for producing a failure signal when said maximum pressure level is lower than said third threshold; failure predicting signal transmitting means for transmitting a failure predicting signal when the number of times at which said failure signal is produced reaches a predetermined count; and setting means for setting said first threshold, said second threshold, said third threshold, and said predetermined count. - View Dependent Claims (19, 20, 21)
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Specification