Patent US4841221A successfully refreshed from Google Patents.
US4841221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Position-sensing circuit
Assignee: Lutron Technology Co LLC
•
Filing: 1988-04-27
•
Granted: 1989-06-20
•
Expires: 2008-04-27
Abstract
Abstract A position-sensing circuit includes an elongated electrically-conductive element divided into two elongated segments. A conductor moves along the element, maintaining electrical contact with at least one of the segments. A first capacitor is connected to the conductor and a second capacitor is connected to one of the segments. When the conductor bridges a gap between the segments, a step-wise change in the time constant of the circuit results. This step-wise change precisely and reproducibly indicates the position of the conductor as being across the gap. The circuit finds particular advantage in a three-way dimming system that permits a remote switch to provide power to a load even if a dimmer that controls the load has been set to provide minimum or no power to the load.
Inventors
- 👤 Jonathan A. Barney
- 👤 Arjuna R. Karunaratne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:06
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
97 words
A bistable position-sensing circuit comprising: (a) an elongated first electrically-conductive element having first and second segments, (b) a second electrically-conductive element, movable along the length of said first element, while maintaining electrical contact with said first segment, said second segment, or both segments, (c) a first energy-storage element electrically connected to said second element, and (d) a second energy-storage element electrically connected to said first segment and to said first energy-storage element, whereby a time constant of said circuit undergoes a step-wise change when said second element is positioned to contact both segments of said first element.
Claim 2
Dependent Claim
97 words
A bistable position-sensing circuit comprising: (a) an elongated first electrically-conductive element having first and second segments, (b) a second electrically-conductive element, movable along the length of said first element, while maintaining electrical contact with said first segment, said second segment, or both segments, (c) a first energy-storage element electrically connected to said second element, and (d) a second energy-storage element electrically connected to said first segment and to said first energy-storage element, whereby a time constant of said circuit undergoes a step-wise change when said second element is positioned to contact both segments of said first element.
Claim 3
Dependent Claim
19 words
The circuit of claim 1 in which said first electrically-conductive element is a resistive element of a slide potentiometer.
Claim 4
Dependent Claim
18 words
The circuit of claim 2 in which said second electrically-conductive element is a wiper of the slide potentiometer.
Claim 5
Dependent Claim
21 words
The circuit of claim 1 in which said first and second segments are arranged end-to-end and separated by a narrow gap.
Claim 6
Dependent Claim
30 words
The circuit of claim 4 in which said gap has a generally rectangular shape and its long dimension makes an acute angle with the long dimension of said first element.
Claim 7
Dependent Claim
33 words
The circuit of claim 5 in which the long dimension of said gap makes an angle in the range between about 20° and about 45° with the long dimension of said first element.
Claim 8
Dependent Claim
34 words
The circuit of claim 1 in which said first and second segments are elongated and, over at least a part of their length, are separated along a direction substantially normal to their long direction.
Claim 9
Dependent Claim
15 words
The circuit of claim 1 in which said first and second energy-storage elements are capacitors.
Claim 10
Dependent Claim
21 words
The circuit of claim 8, further comprising a third electrically-conductive element electrically connected to said first segment and said second capacitor.
Claim 11
Dependent Claim
21 words
The circuit of claim 9, further comprising a switch means that contacts either said second segment or said third electrically-conductive element.
Claim 12
Independent Claim
216 words
A system for controlling electrical power to a load comprising, in combination: (a) a phase-control dimming system to control power to said load in accordance with a signal provided by a control circuit, which includes a potentiometer positionable for determining the value of said control signal, said potentiometer comprising (i) an elongated resistive element, having first and second segments, and (ii) a wiper that is movable along the length of said resistive element, while maintaining electrical contact with said first segment, said second segment, or both segments; (b) a first capacitor electrically connected to said wiper and to a second capacitor, said second capacitor being electrically connected to said first segment of said resistive element and to an override resistor, whose resistance is less than the resistance of said second segment, whereby, when said wiper is moved along said second segment to contact both segments of said resistive element, a time constant of said control circuit undergoes a step-wise increase, thereby turning off power to said load; and (c) a first switch means, which (i) if power to said load is on, turns said power off, and (ii) if power to said load is off, turns said power on to a value determined either by said potentiometer position or by the value of said override resistor.
Claim 13
Independent Claim
216 words
A system for controlling electrical power to a load comprising, in combination: (a) a phase-control dimming system to control power to said load in accordance with a signal provided by a control circuit, which includes a potentiometer positionable for determining the value of said control signal, said potentiometer comprising (i) an elongated resistive element, having first and second segments, and (ii) a wiper that is movable along the length of said resistive element, while maintaining electrical contact with said first segment, said second segment, or both segments; (b) a first capacitor electrically connected to said wiper and to a second capacitor, said second capacitor being electrically connected to said first segment of said resistive element and to an override resistor, whose resistance is less than the resistance of said second segment, whereby, when said wiper is moved along said second segment to contact both segments of said resistive element, a time constant of said control circuit undergoes a step-wise increase, thereby turning off power to said load; and (c) a first switch means, which (i) if power to said load is on, turns said power off, and (ii) if power to said load is off, turns said power on to a value determined either by said potentiometer position or by the value of said override resistor.
Claim 14
Dependent Claim
16 words
The system of claim 11 in which said first switch means is a momentary contact switch.
Claim 15
Dependent Claim
23 words
The system of claim 11 further comprising at least one additional switch means to alternatively perform the functions of said first switch means.
Claim 16
Dependent Claim
12 words
The system of claim 11 in which said override resistor is variable.
Claim 17
Dependent Claim
13 words
The system of claim 11 in which said load is a lighting load.
References Cited (Backward Citations)
US4259619A
Cited
US4225808A
Cited
US4567375A
Cited
US4379237A
Cited
US4482844A
Cited
US4568876A
Cited
US4563592A
Cited
US4693111A
Cited
US4772824A
Cited
US4689547A
Cited
US4745351A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |