Patent US3120977A successfully refreshed from Google Patents.
Patent US4649759A successfully refreshed from Google Patents.
US4649759A
Expired / Lapsed
US
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Force transducer
Assignee: Setra Systems LLC
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Filing: 1985-01-25
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Granted: 1987-03-17
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Expires: 2005-01-25
Abstract
Abstract Two pairs of parallel plate electrodes forming respectively a sensor capacitor and a reference capacitor are mounted on a parallelogram structure designed to deform under load in such a way that the gap width of the sensor capacitor changes as a function of load while the gap width of the reference capacitor is unaffected by the load. The capacitance of the reference capacitor is, however, similarly affected by temperature, humidity and other physical properties which may affect the dielectric constant of the medium, and is available for use in a ratio circuit to compensate for spurious changes in the sensor capacitance.
Inventors
- 👤 Shih-Ying Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:10
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/14; G01L1/142; G01G; G01G3/00; G01G3/12; G01G7/00; G01G7/06
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
333 words
A force transducer, comprising a pair of opposed, rigid force summing members, formed of a dielectric material, each of said summing members including a sensor member projecting therefrom parallel to a central axis toward the other summing member, said sensor members including opposing sensing portions spaced from each other in the direction of an input axis which is perpendicular to said central axis, first and second parallel coupling beam members formed of a dielectric material lying generally in the plane of said input and central axes and extending parallel to said central axis between said force summing members and connected thereto, said first and second beam members being relatively flexible along their respective lengths about axes parallel to a flex axis which is perpendicular to said central and input axes, said first and second beam members being substantially rigid otherwise, said first and second beam members and said force summing members together forming a parallelogram structure, coplanar with said central and input axes, that flexes elastically at said beam members in response to force applied generally along said input axis, whereby the resulting relative displacement of said sensing portions is related to the forces applied to said summing member, a first pair of opposed, parallel electrical conductors affixed to said sensing portions, respectively, said first pair of conductors being offset in the direction of said input axis under the application of force, whereby the capacitance associated with said first pair of conductors is related to the forces applied to said force summing members, an auxiliary member projecting from one of said summing members parallel to said central axis toward the other summing member spaced along said input axis from the adjacent sensor member of said one summing member, and a second pair of opposed, parallel electrical conductors affixed, respectively, to said auxiliary member and said adjacent sensor member, whereby the spacing between said second pair of conductors is relatively fixed so that said second pair of conductors may serve as a reference capacitor.
Claim 2
Dependent Claim
333 words
A force transducer, comprising a pair of opposed, rigid force summing members, formed of a dielectric material, each of said summing members including a sensor member projecting therefrom parallel to a central axis toward the other summing member, said sensor members including opposing sensing portions spaced from each other in the direction of an input axis which is perpendicular to said central axis, first and second parallel coupling beam members formed of a dielectric material lying generally in the plane of said input and central axes and extending parallel to said central axis between said force summing members and connected thereto, said first and second beam members being relatively flexible along their respective lengths about axes parallel to a flex axis which is perpendicular to said central and input axes, said first and second beam members being substantially rigid otherwise, said first and second beam members and said force summing members together forming a parallelogram structure, coplanar with said central and input axes, that flexes elastically at said beam members in response to force applied generally along said input axis, whereby the resulting relative displacement of said sensing portions is related to the forces applied to said summing member, a first pair of opposed, parallel electrical conductors affixed to said sensing portions, respectively, said first pair of conductors being offset in the direction of said input axis under the application of force, whereby the capacitance associated with said first pair of conductors is related to the forces applied to said force summing members, an auxiliary member projecting from one of said summing members parallel to said central axis toward the other summing member spaced along said input axis from the adjacent sensor member of said one summing member, and a second pair of opposed, parallel electrical conductors affixed, respectively, to said auxiliary member and said adjacent sensor member, whereby the spacing between said second pair of conductors is relatively fixed so that said second pair of conductors may serve as a reference capacitor.
Claim 3
Dependent Claim
20 words
The transducer of claim 1, further comprising means for electrically shielding the capacitor formed by each of said corresponding conductors.
Claim 4
Dependent Claim
29 words
The transducer of claim 2, wherein said shielding means includes a pair of electrically conductive layers parallel to each pair of said conductors and arranged on opposite sides thereof.
Claim 5
Dependent Claim
62 words
The transducer of claim 3, further comprising a plurality of capacitive plate assemblies each including a two sided dielectric slab having metal layers affixed to the two respective sides of said slab and means for mounting each said assembly such that one of said layers forms a corresponding one of said conductors and the other of said layers forms an electrical shield.
Claim 6
Dependent Claim
24 words
The transducer of claim 4, wherein said mounting means includes means for rigidly mounting each said assembly in spaced relationship with the corresponding member.
Claim 7
Dependent Claim
25 words
The transducer of claim 5, wherein said mounting means includes at least three pedestals of bonding material between each said assembly and the respective member.
Claim 8
Dependent Claim
21 words
The transducer of claim 4, further including means for electrically interconnecting the shielding layers in each corresponding pair of said assemblies.
Claim 9
Dependent Claim
28 words
The transducer of claim 1, wherein said force summing members, coupling beam members, sensor members and auxiliary member are formed by a single monolithic body of dielectric material.
Claim 10
Dependent Claim
13 words
The transducer of claim 8, wherein said monolithic body is a molded ceramic.
Claim 11
Dependent Claim
16 words
The transducer of claim 1, wherein said first and second pairs of conductors are substantially identical.
Claim 12
Dependent Claim
26 words
The transducer of claim 1, wherein said auxiliary member is substantially identical in geometry and mass to the sensor member projecting from said other summing member.
Claim 13
Dependent Claim
37 words
The transducer of claim 1, wherein said adjacent sensor member projecting from said one summing member is longer than the sensor member projecting from said other summing member, said sensor members being arranged in an overlapping relationship.
Claim 14
Dependent Claim
25 words
The transducer of claim 12, wherein the sensing portion of said adjacent sensor member being located near the end of said adjacent longer sensor member.
Claim 15
Dependent Claim
34 words
The transducer of claim 13, wherein one of the conductors in said other pair of conductors forming said reference capacitor islocated near the juncture of said longer sensor member with said one summing member.
Claim 16
Dependent Claim
20 words
The transducer of claim 14, wherein the capacitors formed by said first and second pairs of conductors are substantially coplanar.
Claim 17
Dependent Claim
34 words
The transducer of claim 15, wherein said sensor member projecting from said other summing member and said auxiliary member projecting from said one summing member are identical in geometry and mass and symmetrically disposed.
Claim 18
Dependent Claim
27 words
The transducer of claim 16, wherein said sensor member of said other summing member and said auxiliary member are aligned with each other in gapped opposing relationship.
Claim 19
Dependent Claim
19 words
The transducer of claim 1, wherein said first and second pairs of conductors are located between said beam members.
Claim 20
Dependent Claim
229 words
A force transducer, comprising a dielectric parallelogram structure having two opposite sides formed of relatively flexible beams connected to two other opposite sides formed of relatively rigid members, means for applying force to said structure along an input axis perpendicular to said beams whereby the parallelogram structure is deformed, first and second sensor arms projecting respectively from two of said opposite sides, the ends of said arms being in spaced overlapping relationship with each other, a first pair of corresponding capacitor plate elements mounted in spaced opposition on said first and second sensor arms, respectively, and a second pair of corresponding capacitor plate elements mounted in fixed spaced opposition and rigidly connected to said structure at a location where the spacing between said second pair of elements is unaffected by deformation of said structure by the applied force, at least one of said second pair of elements being located on a surface of said structure on which neither of said first pair of elements are located, whereby deformation of said parallelogram structure by force applied along said input axis causes relative displacement of said first and second arms which altes the spacing between the corresponding first pair of elements to provide a force-dependent variable capacitance while the spacing between the other corresponding pair of elements remains relatively fixed so that said second pair of elements provides a reference capacitance.
Claim 21
Dependent Claim
229 words
A force transducer, comprising a dielectric parallelogram structure having two opposite sides formed of relatively flexible beams connected to two other opposite sides formed of relatively rigid members, means for applying force to said structure along an input axis perpendicular to said beams whereby the parallelogram structure is deformed, first and second sensor arms projecting respectively from two of said opposite sides, the ends of said arms being in spaced overlapping relationship with each other, a first pair of corresponding capacitor plate elements mounted in spaced opposition on said first and second sensor arms, respectively, and a second pair of corresponding capacitor plate elements mounted in fixed spaced opposition and rigidly connected to said structure at a location where the spacing between said second pair of elements is unaffected by deformation of said structure by the applied force, at least one of said second pair of elements being located on a surface of said structure on which neither of said first pair of elements are located, whereby deformation of said parallelogram structure by force applied along said input axis causes relative displacement of said first and second arms which altes the spacing between the corresponding first pair of elements to provide a force-dependent variable capacitance while the spacing between the other corresponding pair of elements remains relatively fixed so that said second pair of elements provides a reference capacitance.
Claim 22
Dependent Claim
21 words
The transducer of claim 19, wherein one of said second pair of elements is mounted on one of said sensor arms.
Claim 23
Dependent Claim
22 words
The transducer of claim 19, wherein said second pair of elements is rigidly connected to the same one of said rigid members.
Claim 24
Dependent Claim
34 words
The transducer of claim 19, wherein said arms are connected to said rigid members and said second pair of elements is connected respectively to one of said rigid members and the arm projecting therefrom.
Claim 25
Dependent Claim
15 words
The transducer of claim 19, wherein said arms are connected to said flexible beams, respectively.
Claim 26
Dependent Claim
22 words
The transducer of claim 19, wherein said parallelogram structure and sensor arms are formed by a single monolithic body of dielectric material.
Claim 27
Dependent Claim
13 words
The transducer of claim 24, wherein said monolithic body is a molded ceramic.
Claim 28
Dependent Claim
14 words
The transducer of claim 19, wherein said capacitor plate elements are all substantially identical.
Claim 29
Dependent Claim
25 words
The transducer of claim 26, wherein said capacitor plate elements in one pair are coplanar with the corresponding capacitor plate elements in the other pair.
Claim 30
Dependent Claim
23 words
The transducer of claim 27, wherein said capacitor plate elements are all substantially parallel and perpendicular to the plane of said parallelogram structure.
Claim 31
Dependent Claim
23 words
The transducer of claim 19, further comprising means for electrically shielding the capacitor formed by each of said pair of capacitor plate elements.
Claim 32
Dependent Claim
28 words
The transducer of claim 29, wherein said shielding means includes a pair of electrically conductive layers parallel to said capacitor plate elements and arranged on opposite sides thereof.
Claim 33
Dependent Claim
64 words
The transducer of claim 30, further comprising a plurality of capacitive plate assemblies each including a two sided dielectric slab having metal layers affixed to the two respective sides of said slab and means for mounting each said assembly such that one of said layers forms a corresponding one of said capacitor plate elements and the other of said layers forms an electrical shield.
Claim 34
Dependent Claim
24 words
The transducer of claim 31, wherein said mounting means includes means for rigidly mounting each said assembly in spaced relationship with the corresponding member.
Claim 35
Dependent Claim
25 words
The transducer of claim 32, wherein said mounting means includes at least three pedestals of bonding material between each said assembly and the respective member.
Claim 36
Dependent Claim
21 words
The transducer of claim 31, further including means for electrically interconnecting the shielding layers in each corresponding pair of said assemblies.
Claim 37
Dependent Claim
169 words
A capacitive force transducer, comprising a dielectric parallelogram structure including two opposite sides formed by relatively flexible beams connected to two other opposite sides formed by relatively inflexible side members, means for applying force to said structure along an input axis perpendicular to said beams whereby said parallelogram structure is deformed, first and second sensor arms rigidly connected respectively to corresponding side members and projecting therefrom so that their free ends overlap in spaced relationship, spaced opposed parallel sensing elements affixed to corresponding locations on said first and second arms respectively for relative displacement upon deformation of said parallelogram, each said sensing element including a dielectric slab having two faces, each of which carries a parallel, electrically conductive layer, means for mounting the sensing elements on the respective arms such that the conductive layers are all parallel to each other, the two inner layers facing each other defining a variable capacitor, and means for electrically interconnecting the other outer layers of said sensing elements to form an electrical shield.
Claim 38
Dependent Claim
169 words
A capacitive force transducer, comprising a dielectric parallelogram structure including two opposite sides formed by relatively flexible beams connected to two other opposite sides formed by relatively inflexible side members, means for applying force to said structure along an input axis perpendicular to said beams whereby said parallelogram structure is deformed, first and second sensor arms rigidly connected respectively to corresponding side members and projecting therefrom so that their free ends overlap in spaced relationship, spaced opposed parallel sensing elements affixed to corresponding locations on said first and second arms respectively for relative displacement upon deformation of said parallelogram, each said sensing element including a dielectric slab having two faces, each of which carries a parallel, electrically conductive layer, means for mounting the sensing elements on the respective arms such that the conductive layers are all parallel to each other, the two inner layers facing each other defining a variable capacitor, and means for electrically interconnecting the other outer layers of said sensing elements to form an electrical shield.
Claim 39
Dependent Claim
21 words
The transducer of claim 35, further comprising means for mounting each said sensing element in spaced relationship with the respective arm.
Claim 40
Dependent Claim
29 words
The transducer of claim 36, wherein said mounting means includes for each sensing element at least three pedestals of cementing material between the sensing element and the respective arm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-16 | 1990-09-15 | 1991-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-16 | 1994-09-15 | 1995-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-16 | 1998-09-15 | 1999-03-17 | $7700.00 | Window Closed / Lapsed |