US5339022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitive cable length indicator
Assignee: Whitaker LLC
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Filing: 1992-09-24
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Granted: 1994-08-16
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Expires: 2012-09-24
Abstract
Abstract A cable length indicating arrangement which utilizes the capacitance of a two wire cable (10) to determine its length. The arrangement includes an oscillator stage (14) having a frequency setting capacitor (16) across which the cable is connected. The frequency of oscillation is converted into a voltage which is provided as the input to a comparator network (70, 72, 74, 76, 78, 80) which compares this voltage against voltages derived from a voltage divider network (96, 98, 100, 102, 104, 106, 108). The comparator network includes a "ladder" of comparators each having their non-inverting inputs coupled to receive the frequency dependent voltage and their inverting inputs each connected to a respective point in a resistive divider string. The outputs of the comparators are connected to respective light emitting diodes (82, 84, 86, 88, 90, 92). As the length of the cable is increased and its capacitance increases, the frequency of oscillation decreases, the frequency dependent voltage decreases, and the light emitting diodes are energized one by one, to provide a bar graph display indicative of cable length.
Inventors
- 👤 David F. Fleming
- 👤 James M. Raudenbush
- 👤 Raymond M. Carlisle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:22
CPC Classifications
G; G01; G01B; G01B7/00; G01B7/02; G01B7/026
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
206 words
An arrangement for indicating the length of a cable (10) made up of two wires (24, 26), comprising: an electrical oscillator stage (14) including a frequency setting capacitor (16); means (30, 32) for connecting a first (24) of said cable wires to a first side of said capacitor and the other (26) of said cable wires to the other side of said capacitor; means (18) for providing a voltage corresponding to the frequency of oscillation of the oscillator stage; and means (20) for displaying a visual representation of said voltage; wherein said oscillator stage (14) comprises: a comparator (40) having an output terminal (42), an inverting input terminal (44) and a non-inverting input terminal (46); first resistor means (48, 50) coupling said non-inverting input terminal to a first reference potential; second resistor means (52) coupling said non-inverting input terminal to a second reference potential higher than said first reference potential; third resistor means (54) coupling said non-inverting input terminal (46) to said output terminal (42); fourth resistor means (56) coupling said inverting input terminal (44) to said output terminal (42); means for coupling said capacitor first side to said inverting input terminal (44); and means for coupling said capacitor second side to said first reference potential.
Claim 2
Dependent Claim
206 words
An arrangement for indicating the length of a cable (10) made up of two wires (24, 26), comprising: an electrical oscillator stage (14) including a frequency setting capacitor (16); means (30, 32) for connecting a first (24) of said cable wires to a first side of said capacitor and the other (26) of said cable wires to the other side of said capacitor; means (18) for providing a voltage corresponding to the frequency of oscillation of the oscillator stage; and means (20) for displaying a visual representation of said voltage; wherein said oscillator stage (14) comprises: a comparator (40) having an output terminal (42), an inverting input terminal (44) and a non-inverting input terminal (46); first resistor means (48, 50) coupling said non-inverting input terminal to a first reference potential; second resistor means (52) coupling said non-inverting input terminal to a second reference potential higher than said first reference potential; third resistor means (54) coupling said non-inverting input terminal (46) to said output terminal (42); fourth resistor means (56) coupling said inverting input terminal (44) to said output terminal (42); means for coupling said capacitor first side to said inverting input terminal (44); and means for coupling said capacitor second side to said first reference potential.
Claim 3
Dependent Claim
36 words
The arrangement according to claim 1 further including: fifth resistor means (58) coupled to said output terminal (42); and a light emitting diode (60) connected between said fifth resistor means (58) and said second reference potential.
Claim 4
Dependent Claim
25 words
The arrangement according to claim 1 wherein said first resistor means (48, 50) includes a variable resistor (50) so that said arrangement can be calibrated.
Claim 5
Dependent Claim
79 words
The arrangement according to claim 1 wherein said displaying means (20) includes: a plurality of light emitting elements (82, 84, 86, 88, 90, 92) positioned in a linear array; and energizing means (70, 72, 74, 76, 78, 80, 94, 96, 98, 100, 102, 104, 106, 108) coupled to receive said voltage from said voltage providing means for selectively energizing said light emitting diodes to provide a bar of light extending in direct dependence on the length of the cable.
Claim 6
Dependent Claim
167 words
The arrangement according to claim 4 wherein said light emitting elements are light emitting diodes and said energizing means comprises: a plurality of comparators (70, 72, 74, 76, 78, 80) each having an output terminal, an inverting input terminal and a non-inverting input terminal; means for coupling the non-inverting input terminals of all of said plurality of comparators to receive said voltage from said voltage providing means (18); a plurality of resistors (96, 98, 100, 102, 104, 106, 108) connected in series between a first reference potential and a second reference potential, there being one more resistor in said plurality of resistors than there are comparators in said plurality of comparators; means for connecting the inverting inputs of said plurality of comparators each to a respective junction between resistors in the series connection of said plurality of resistors; and means for connecting said plurality of light emitting diodes each between the output terminal of a respective one of said plurality of comparators and said second reference potential.
Claim 7
Dependent Claim
35 words
The arrangement according to claim 1 wherein said voltage providing means includes: a one-shot multivibrator circuit (63) coupled to said oscillator stage (14); and an integrator circuit (66, 68) coupled to said one-shot multivibrator circuit.
Claim 8
Dependent Claim
46 words
The arrangement according to claim 1 wherein said arrangement is selectively powered from a battery (34) and said connecting means (30, 32) comprises means for completing a circuit path for said battery so that said connecting means operates as a power control switch for said arrangement.
Claim 9
Dependent Claim
64 words
The arrangement according to claim 7 wherein said connecting means includes: a jack (30) having a first terminal and a second terminal; means for connecting said first jack terminal to a first terminal of said battery (34); means for connecting said second jack terminal to ground; and means (32) mating with said jack for connecting said first jack terminal to said second jack terminal.
References Cited (Backward Citations)
US2285152A
Cited
US2601649A
Cited
US3651505A
Cited
US3781672A
Cited
US3821659A
Cited
US3987392A
Cited
US3879660A
Cited
US4103225A
Cited
US4199984A
Cited
US4459541A
Cited
US4517547A
Cited
US4820991A
Cited
US4907449A
Cited
US4812752A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-15 | 1998-02-14 | 1998-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-15 | 2002-02-14 | 2002-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-15 | 2006-02-14 | 2006-08-16 | $7700.00 | Window Closed / Lapsed |