US4282688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adjustable CTE graphite-epoxy bar
Assignee: Applied Biosystems Inc
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Filing: 1979-07-05
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Granted: 1981-08-11
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Expires: 1999-07-05
Abstract
Abstract A structural element and method of fabricating a structural element having a zero expansion in a given direction. A bar member having left and right hand sections of positive and negative coefficients of thermal expansion is tuned so that expansion of one section is exactly offset by contraction of the other section in a varying temperature environments.
Inventors
- 👤 Michael K. Krim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:36
CPC Classifications
G; G01; G01B; G01B5/00; G01B5/0011; G01B5/0014; G12; G12B; G12B7/00; Y; Y10; Y10S; Y10S248/00; Y10S248/901
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
75 words
A structural element having a specific overall expansivity along a given axis, comprising in combination; a member comprising first and second sections integrally formed therewith, said member comprising a plurality of layers of graphite epoxy composite, each of said sections having a length and coefficient of thermal expansion such that overall expansion or contraction is zero and wherein, the layers in said first section have different wrap angles from the layers in said second section.
Claim 2
Dependent Claim
75 words
A structural element having a specific overall expansivity along a given axis, comprising in combination; a member comprising first and second sections integrally formed therewith, said member comprising a plurality of layers of graphite epoxy composite, each of said sections having a length and coefficient of thermal expansion such that overall expansion or contraction is zero and wherein, the layers in said first section have different wrap angles from the layers in said second section.
Claim 3
Dependent Claim
20 words
A structural element according to claim 1 wherein the number of layers in said first and second sections are different.
Claim 4
Dependent Claim
63 words
A structural element according to claim 1 wherein, the length of said first and second sections may be determined by the equation ##EQU5## where L s =length of one of said sections L o =desired length of said member α.sub. = coefficients of thermal expansion of the other of said sections α 2 =coefficient of thermal expansion of said one of said sections.
Claim 5
Independent Claim
108 words
A method for fabricating a structural element comprising the steps of forming a member having a first section with a negative coefficient of thermal expansion and a second section having a positive coefficient of thermal expansion, measuring the coefficient of thermal expansion of portions of said first and second sections, calculating the necessary length of one of said sections to give a desired expansivity for a given length of the member, cutting off a portion of said one of said sections to shorten it to the required length, cutting off a portion of the other of said sections to cause said member to conform to said given length.
Claim 6
Independent Claim
108 words
A method for fabricating a structural element comprising the steps of forming a member having a first section with a negative coefficient of thermal expansion and a second section having a positive coefficient of thermal expansion, measuring the coefficient of thermal expansion of portions of said first and second sections, calculating the necessary length of one of said sections to give a desired expansivity for a given length of the member, cutting off a portion of said one of said sections to shorten it to the required length, cutting off a portion of the other of said sections to cause said member to conform to said given length.
Claim 7
Dependent Claim
30 words
A method according to claim 4 wherein said step of forming includes the step of determining the transition point of the member at which the coefficients of thermal expansion change.
Claim 8
Dependent Claim
22 words
A method according to claim 5 wherein said step of measuring is preceded by a step of heat curing said structural element.
Claim 9
Dependent Claim
37 words
A method according to claim 6 wherein the step of measuring includes the steps of cutting small portions from the ends of each section and determining the coefficient of thermal expansion of each by a Fizean interferometer.
Claim 10
Dependent Claim
56 words
A method according to claim 7 wherein the step of calculating includes the step of, solving the equation ##EQU6## where L 2 =length of one of said second sections L o =desired length of said member α.sub. = coefficient of thermal expansion of said first section α 2 =coefficient of thermal expansion of said second sections.
Claim 11
Dependent Claim
70 words
A method according to claim 8 wherein the steps of cutting include, measuring the length L 2 from the transition zone and removing a portion of said second section to make it conform to the length L 2 , measuring the length L o back the cut of said second section and removing the portion of said first section to make the member conform to the length L o .
Claim 12
Dependent Claim
79 words
A truss, comprising in combination, a plurality of struts each of said struts composed of first and second sections having a length and coefficient of thermal expansion such that overall expansion or contraction of the strut due to temperature variations is zero, first and second rings, each of said struts having an end fixed to each of said rings, each of said first and second rings connected to alternate ends of said first and second sections of said struts.
Claim 13
Dependent Claim
79 words
A truss, comprising in combination, a plurality of struts each of said struts composed of first and second sections having a length and coefficient of thermal expansion such that overall expansion or contraction of the strut due to temperature variations is zero, first and second rings, each of said struts having an end fixed to each of said rings, each of said first and second rings connected to alternate ends of said first and second sections of said struts.
Claim 14
Dependent Claim
19 words
A truss according to claim 10 wherein each pair of struts form a triangle with one of said rings.
Claim 15
Dependent Claim
65 words
A truss according to claim 11 wherein, the length of said first and second sections may be determined by the equation L.sub.2 =(α.sub.1 /α.sub.1 α.sub.2)L.sub.o where L 2 =length of one of said sections L o =desired length of a strut α 1 =coefficient of thermal expansion of the other of said sections α 2 =coefficient of thermal expansion of said one of said sections.
Claim 16
Dependent Claim
71 words
A structural element having a specific overall expansivity along a given axis, comprising in combination; a member comprising first and second sections integrally formed therewith, said member comprising a plurality of layers of graphite epoxy composite, each of said sections having a length and coefficient of thermal expansion such that overall expansion on contraction has a predetermined value wherein the number of layers in said first and second sections are different.
Claim 17
Dependent Claim
71 words
A structural element having a specific overall expansivity along a given axis, comprising in combination; a member comprising first and second sections integrally formed therewith, said member comprising a plurality of layers of graphite epoxy composite, each of said sections having a length and coefficient of thermal expansion such that overall expansion on contraction has a predetermined value wherein the number of layers in said first and second sections are different.
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) | 1984-08-10 | 1985-02-09 | 1985-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-10 | 1989-02-09 | 1989-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-10 | 1993-02-09 | 1993-08-11 | $7700.00 | Window Closed / Lapsed |