US5020366A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level sensor
Assignee: Scandmec Plast AB
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Filing: 1990-06-18
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Granted: 1991-06-04
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Expires: 2010-06-18
Abstract
Abstract Liquid level sensor comprising a rod (2) on which a first (4) and a second (5) resistance wire are wound helically and parallel, a float (3) which is displaceable along the rod and which comprises a contact element which has a first (11) and a seond (12) contact plate, which each make contact with one of the resistance wires (4, 5) respectively, and a circuit which runs through the resistance wires and the contact element and whose resistivity varies depending on the position of hte float along the rod, in which respect the resistance wire (4) is recessed in the rod in the area in which the resistance wire (5) bears against the contact plate (12) while the resistance wire (5) is recessed in the rod in the area in which the resistance wire (4) bears against the contact plate.
Inventors
- 👤 Sven Elfverson
- 👤 Kenneth Skogward
- 👤 Bengt Hermansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:27
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/30; G01F23/64; G01F23/68; H; H01; H01C; H01C10/00; H01C10/30; H01C10/301
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
158 words
A liquid level sensor comprising a rod of insulating material, a float of insulating material surrounding said rod and being displaceable along the rod first and second resistance wires, a contact element arranged on the float and electrically connected to said first and second resistance wires to provide a current circuit whose resistivity varies depending on the position of the float along the rod, said contact element comprising a first contact plate for the first resistance wire and a second contact plate for the second resistance wire, the float including stabilizing means for preventing said float from turning about the rod the resistance wires being wound helically and parallel about the rod with the first wire being recessed in the rod in the area in which the second resistance wire bears against the contact plate and the second wire being recessed in the rod in the area in which the first resistance wire bears against the contact plate.
Claim 2
Dependent Claim
158 words
A liquid level sensor comprising a rod of insulating material, a float of insulating material surrounding said rod and being displaceable along the rod first and second resistance wires, a contact element arranged on the float and electrically connected to said first and second resistance wires to provide a current circuit whose resistivity varies depending on the position of the float along the rod, said contact element comprising a first contact plate for the first resistance wire and a second contact plate for the second resistance wire, the float including stabilizing means for preventing said float from turning about the rod the resistance wires being wound helically and parallel about the rod with the first wire being recessed in the rod in the area in which the second resistance wire bears against the contact plate and the second wire being recessed in the rod in the area in which the first resistance wire bears against the contact plate.
Claim 3
Dependent Claim
16 words
A liquid level sensor according to claim 1, wherein the rod (2) has a non-circular cross-section.
Claim 4
Dependent Claim
27 words
A liquid level sensor according to claim 1 or 2, wherein the helically wound resistance wires have a uniform pitch along the length of the entire rod.
Claim 5
Dependent Claim
22 words
A liquid level sensor according to claim 1 or 2, wherein the helically wound wires have a variable pitch along the rod.
Claim 6
Dependent Claim
32 words
A liquid level sensor according to claim 1, wherein the contact plates extend in the axial direction between at least two consecutive winding turns of their respective first and second resistance wires.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-03 | 1994-12-03 | 1995-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-03 | 1998-12-03 | 1999-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-03 | 2002-12-03 | 2003-06-04 | $7700.00 | Window Closed / Lapsed |