US3900649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moulded articles
Assignee: Worldwide Plastics Development Ltd
•
Filing: 1974-01-25
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Granted: 1975-08-19
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Expires: 1994-01-25
Abstract
Abstract A composite article comprising a metal reinforcing core completely encapsulated in a covering layer of plastics material which has a co-efficient of thermal expansion over a predetermined temperature range greater than the coefficient of thermal expansion of the metal core which presents to the plastics material a first smoothly curved concave surface which, at a first temperature at the upper end of said range, is engaged by, but not bonded to, a portion of the covering layer which has a second, concave, smoothly curved, external surface, the first and second surfaces being aligned, the curvature of said first surface and the thickness of said portion being such that at a second temperature at the lower end of said range said portion has lifted away from said first surface thus reducing the tensile stresses which occur in said portion due to differential contraction of the plastics material and the core as the temperature of the article is reduced from the upper end to the lower end of said temperature range as compared with the tensile stresses which would occur in the plastics material if it were unable to lift off said first concave surface.
Inventors
- 👤 Frederick Leslie Hart
- 👤 Herbert John Sharp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:21
CPC Classifications
B; B29; B29C; B29C63/00; B29C63/38; B29C63/42; B29C63/0065; B29C63/0069; B29C63/18; E; E06; E06B; E06B3/00; E06B3/04; E06B3/06; E06B3/08; E06B3/20; E06B3/205; B29K; B29K2705/00; B29K2705/02; B29K2705/08; B29K2705/12; B29L; B29L2009/00; B29L2009/001; B29L2009/003; B29L2031/00; B29L2031/001; B29L2031/003; B29L2031/005; Y; Y10; Y10S; Y10S228/00; Y10S228/903; Y10T; Y10T428/00; Y10T428/23; Y10T428/239; Y10T428/24; Y10T428/24025; Y10T428/24942; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/2938
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
257 words
A COMPOSITE ARTICLE COMPRISING A RIGID, METAL REINFORCING CORE COMPLETELY EMBEDDED IN A COVERING LAYER OF PLASTICS MATERIAL SO THAT THE EXTERNAL SURFACE OF THE CORE AND THE INTERNAL SURFACE OF THE COVERING LAYER OF PLASTICS MATERIAL ARE FREE TO MOVE RELATIVE TO ONE ANOTHER AND ARE NOT BONDED TOGETHER, THE PLASTICS MATERIAL HAVING A COEFFICIENT OF THERMAL EXPANSION OVER A PREDETERMINED TEMPERATURE RANGE GREATER THAN THE CO-EFFICIENT OF THERMAL EXPANSION OF THE METAL OF THE CORE, THE EXTERNAL SURFACE OF THE CORE PRESENTING TO THE INTERNAL SURFACE OF THE COVERING OF PLASTICS MATERIAL A FIRST, SMOOTHLY-CURVED CONCAVE SURFACE PART WHICH, AT A FIRST TEMPERATURE AT THE UPPER END OF SAID RANGE, S ENGAGED BY A PORTION OF THE COVERING LAYER WHICH HAS A SECOND, CONCONCAVE, SMOOTHLY-CURVED, EXTERNAL SURFACE, THE FIRST AND SECOND SURFACES BEING ALIGNED, THE CURVATURUE OF SAID FIRST SURFACE AND THE THICKNESS OF SAID PORTION OF THE COVERING LAYER BEING SUCH THAT AT A SECOND TEMPERATURE AT THE LOWER END OF SAID RANGE SAID PORTION OF THE COVERING LAYER DUE LIFTED AWAY FROM SAID FIRST SURFACE THUS REDUCING THE TENSILE STRESSES WHICH OCCUR IN SAID PORTION OF THE COVERING LAYER DUE TO DIFFERENTIAL CONTRACTION OF THE PLASTICS MATERIAL AND THE METAL OF THE CORE AS THE TEMPERATURE OF THE ARTICLE IS REDUCED FROM THE UPPER END OF SAID TEMPERATURE RANGE TO THE LOWER END OF SAID RANGE AS COMPARED WITH THE TENSION STRESSES WHICH WOULD OCCUR IN SAID PORTION OF THE PLASTIC MATERIAL IF IT WERE UNABLE TO LIFT OFF SAID FIRST CONCACE SURFACE.
Claim 2
Dependent Claim
257 words
A COMPOSITE ARTICLE COMPRISING A RIGID, METAL REINFORCING CORE COMPLETELY EMBEDDED IN A COVERING LAYER OF PLASTICS MATERIAL SO THAT THE EXTERNAL SURFACE OF THE CORE AND THE INTERNAL SURFACE OF THE COVERING LAYER OF PLASTICS MATERIAL ARE FREE TO MOVE RELATIVE TO ONE ANOTHER AND ARE NOT BONDED TOGETHER, THE PLASTICS MATERIAL HAVING A COEFFICIENT OF THERMAL EXPANSION OVER A PREDETERMINED TEMPERATURE RANGE GREATER THAN THE CO-EFFICIENT OF THERMAL EXPANSION OF THE METAL OF THE CORE, THE EXTERNAL SURFACE OF THE CORE PRESENTING TO THE INTERNAL SURFACE OF THE COVERING OF PLASTICS MATERIAL A FIRST, SMOOTHLY-CURVED CONCAVE SURFACE PART WHICH, AT A FIRST TEMPERATURE AT THE UPPER END OF SAID RANGE, S ENGAGED BY A PORTION OF THE COVERING LAYER WHICH HAS A SECOND, CONCONCAVE, SMOOTHLY-CURVED, EXTERNAL SURFACE, THE FIRST AND SECOND SURFACES BEING ALIGNED, THE CURVATURUE OF SAID FIRST SURFACE AND THE THICKNESS OF SAID PORTION OF THE COVERING LAYER BEING SUCH THAT AT A SECOND TEMPERATURE AT THE LOWER END OF SAID RANGE SAID PORTION OF THE COVERING LAYER DUE LIFTED AWAY FROM SAID FIRST SURFACE THUS REDUCING THE TENSILE STRESSES WHICH OCCUR IN SAID PORTION OF THE COVERING LAYER DUE TO DIFFERENTIAL CONTRACTION OF THE PLASTICS MATERIAL AND THE METAL OF THE CORE AS THE TEMPERATURE OF THE ARTICLE IS REDUCED FROM THE UPPER END OF SAID TEMPERATURE RANGE TO THE LOWER END OF SAID RANGE AS COMPARED WITH THE TENSION STRESSES WHICH WOULD OCCUR IN SAID PORTION OF THE PLASTIC MATERIAL IF IT WERE UNABLE TO LIFT OFF SAID FIRST CONCACE SURFACE.
Claim 3
Dependent Claim
28 words
A composite article according to claim 1 wherein the core is in the form of an elongated member and the first concave surface extends longitudinally of the core.
Claim 4
Dependent Claim
62 words
A composite article according to claim 1 wherein the core is in the form of a frame having a number of limbs each of which presents a first, smoothly-curved, concave surface which at said first temperature is engaged by one of said portions of the covering layer of the plastics material which in turn presents an external aligned smoothly curved concave surface.
Claim 5
Dependent Claim
29 words
A composite article according to claim 1 wherein the or each said portion of the plastics material has a substantially constant thickness between said first and second concave surfaces.
References Cited (Backward Citations)
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US3445113A
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US3256532A
Cited
US3725995A
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US3787549A
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US3702355A
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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) | 1978-08-18 | 1979-02-17 | 1979-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-18 | 1983-02-17 | 1983-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-18 | 1987-02-17 | 1987-08-19 | $7700.00 | Window Closed / Lapsed |