US3729991A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitive displacement transducer
Assignee: SPEARHEAD Inc
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Filing: 1971-05-17
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Granted: 1973-05-01
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Expires: 1991-05-17
Abstract
Abstract A capacitive displacement transducer for measuring relative displacement between two points or objects is disclosed as including a driven element connected to a source of input electrical signals, a receptor element connected to an electrical output signal circuit means, and two shield elements mounted between the driven and receptor elements for relative movement with respect to each other. One of the shield elements mechanically responds to one of the objects and the other shield element mechanically responds to the other object and any resulting relative movement between the shield elements changes the capacitive coupling between the driven and receptor elements to provide an electrical output signal proportional to this movement and the displacement between said objects.
Inventors
- 👤 E Hardway
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:35
CPC Classifications
G; G01; G01L; G01L3/00; G01L3/02; G01L3/04; G01L3/10; G01L3/106
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
214 words
Apparatus for converting relative displacement into electrical signals comprising: a conductive driven element adapted to be connected to a source of input electrical signals; a conductive receptor element positioned adjacent said driven element; a first conductive shield element positioned between said driven and receptor elements; a second conductive shield element positioned between said driven and receptor elements and adjacent said first shield element, said first and second shield elements providing a variable shield between said driven and receptor elements in response to relative movement with respect to each other and aligned with respect to each other to vary the capacitance between said driven and receptor elements in response to such relative movement; means for maintaining said first and second shield elements at a substantially lower signal level than the level of said input electrical signals; and means for causing movement of one of said shield elements with respect to the other in response to a relative displacement to be measured, whereby measurable variations in said capacitance responsive to such displacement are provided, and circuit means coupled to said receptor element for developing electrical output signals responsive to said variations in said capacitance, and including means for maintaining said receptor element at a substantially lower signal level than the level of said input electrical signals.
Claim 2
Dependent Claim
214 words
Apparatus for converting relative displacement into electrical signals comprising: a conductive driven element adapted to be connected to a source of input electrical signals; a conductive receptor element positioned adjacent said driven element; a first conductive shield element positioned between said driven and receptor elements; a second conductive shield element positioned between said driven and receptor elements and adjacent said first shield element, said first and second shield elements providing a variable shield between said driven and receptor elements in response to relative movement with respect to each other and aligned with respect to each other to vary the capacitance between said driven and receptor elements in response to such relative movement; means for maintaining said first and second shield elements at a substantially lower signal level than the level of said input electrical signals; and means for causing movement of one of said shield elements with respect to the other in response to a relative displacement to be measured, whereby measurable variations in said capacitance responsive to such displacement are provided, and circuit means coupled to said receptor element for developing electrical output signals responsive to said variations in said capacitance, and including means for maintaining said receptor element at a substantially lower signal level than the level of said input electrical signals.
Claim 3
Dependent Claim
20 words
The apparatus of claim 1 wherein each of said first and second shielded elements are connected to separate movable objects.
Claim 4
Dependent Claim
34 words
The apparatus of claim 2 wherein each of said driven, receptor and shield elements are circular disks and said first and second shield elements are each connected for rotation with a separate rotatable shaft.
Claim 5
Dependent Claim
78 words
The apparatus of claim 3 wherein said variable sHield is formed by a plurality of radial slots in each of said first and second shield elements, the slots of one shield element being adjacent the slots of the other shield element and circumferentially offset from said other slots, to form a plurality of openings between the driven and receptor elements which vary in size in response to angular displacement of one shield element with respect to the other.
Claim 6
Dependent Claim
32 words
The apparatus of claim 1 wherein each of said driven, receptor and shield elements are flat, parallel plates and said shield elements are arranged for linear motion with respect to each other.
Claim 7
Dependent Claim
80 words
The apparatus of claim 1 further including means for mechanically coupling said first shield element to an object at a first point along the object, and means for mechanically coupling said second shield element to the same object at a second point along the object and spaced from the first point, whereby relative movement of said first and second points with respect to each other will cause displacement of said first and second shield elements with respect to each other.
Claim 8
Dependent Claim
38 words
The apparatus of claim 6 wherein said means for causing said relative movement is a rotatable shaft and said first and second shield elements are circular disks and each are mechanically coupled to different points on said shaft.
Claim 9
Dependent Claim
75 words
The apparatus of claim 1 wherein said last mentioned means comprises means for providing an effective capacitance in shunt with the capacitance between said receptor element and said first and second shield elements, said effective capacitance being sufficiently larger than said capacitance between said receptor element and said first and second shield elements so that said receptor element is maintained at a substantially zero signal level with respect to said first and second shield elements.
Claim 10
Dependent Claim
52 words
The apparatus of claim 1 wherein said circuit means includes an amplifier circuit having a negative feedback circuit, said receptor element being coupled to the input circuit of said amplifier circuit so that said receptor is maintained at a substantially zero signal level with respect to the first and second shield elements.
Claim 11
Dependent Claim
25 words
The apparatus of claim 9 wherein said negative feedback circuit includes capacitive means coupled between said input circuit and the output circuit of said amplifier.
Claim 12
Dependent Claim
223 words
Apparatus for sensing torque transmitted between two objects, comprising, a housing; a rotatable shaft passing through said housing and supported for rotation with respect to said housing; a conductive driven element mounted in said housing and adapted to be connected to a source of input electrical signals; a conductive receptor element mounted in said housing adjacent said driven element; a first conductive shield element positioned between said driven and receptor elements; means for mechanically coupling said first shield element to said shaft at a first point along its length; a second conductive shield element positioned between said driven and receptor elements, said first and second shield elements providing a variable shield between said driven and receptor elements in response to relative movement with respect to each other, and aligned with respect to each other to vary the capacitance between said driven and receptor elements in response to said relative movement; means for mechanically coupling said second shield element to said shaft at a second point along its length whereby angular displacement of one of said points with respect to the other in response to a torque to be sensed causes relative movement between said first and second shield elements; and means for maintaining said first and second shield elements and said shaft at substantially zero signal level with respect to said input signals.
Claim 13
Dependent Claim
223 words
Apparatus for sensing torque transmitted between two objects, comprising, a housing; a rotatable shaft passing through said housing and supported for rotation with respect to said housing; a conductive driven element mounted in said housing and adapted to be connected to a source of input electrical signals; a conductive receptor element mounted in said housing adjacent said driven element; a first conductive shield element positioned between said driven and receptor elements; means for mechanically coupling said first shield element to said shaft at a first point along its length; a second conductive shield element positioned between said driven and receptor elements, said first and second shield elements providing a variable shield between said driven and receptor elements in response to relative movement with respect to each other, and aligned with respect to each other to vary the capacitance between said driven and receptor elements in response to said relative movement; means for mechanically coupling said second shield element to said shaft at a second point along its length whereby angular displacement of one of said points with respect to the other in response to a torque to be sensed causes relative movement between said first and second shield elements; and means for maintaining said first and second shield elements and said shaft at substantially zero signal level with respect to said input signals.
Claim 14
Dependent Claim
78 words
The apparatus of claim 11 wherein said variable shield is formed by a plurality of radial slots in each of said first and second shield elements, the slots of one shield element being adjacent the slots of the other shield element and circumferentially offsEt from said other slots, to form a plurality of openings between the driven and receptor elements which vary in size in response to angular displacement of one shield element with respect to the other.
Claim 15
Dependent Claim
47 words
The apparatus of claim 11 further including circuit means coupled to said receptor element for developing electrical output signals responsive to variations in said capacitance, and including means for maintaining said receptor element at substantially zero signal level with respect to said first and second shield elements.
Claim 16
Dependent Claim
78 words
The apparatus of claim 13 wherein said variable shield is formed by a plurality of radial slots in each of said first and second shield elements, the slots of one shield element being adjacent the slots of the other shield element and circumferentially offset from said other slots, to form a plurality of openings between the driven and receptor elements which vary in size in response to angular displacement of one shield element with respect to the other.
Claim 17
Dependent Claim
75 words
The apparatus of claim 13 wherein said last mentioned means comprises means for providing an effective capacitance in shunt with the capacitance between said receptor element and said first and second shield elements, said effective capacitance being sufficiently larger than said capacitance between said receptor element and said first and second shield elements so that said receptor element is maintained at a substantially zero signal level with respect to said first and second shield elements.
Claim 18
Dependent Claim
53 words
The apparatus of claim 13 wherein said circuit means includes an amplifier circuit having a negative feedback circuit, said receptor element being coupled to the input circuit of said amplifier circuit so that said receptor element is maintained at a substantially zero signal level with respect to the first and second shield elements.
Claim 19
Dependent Claim
25 words
The apparatus of claim 16 wherein said negative feedback circuit includes capacitive means coupled between said input circuit and the output circuit of said amplifier.
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) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |