Patent US4574108A successfully refreshed from Google Patents.
US4574108A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fiber reinforced composite
Assignee: University of Delaware
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Filing: 1985-05-02
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Granted: 1986-03-04
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Expires: 2005-05-02
Abstract
Abstract Fibers and plastic materials reinforced with these fibers which have a diameter that varies along the fiber axis are provided. The fibers increase the strength of the material by reducing fiber pull out from the plastic matrix. The variation in diameter results in an undulating surface on the fiber which locks it into the matrix.
Inventors
- 👤 Stoyko C. Fakirov
- 👤 Jerold M. Schultz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:12
CPC Classifications
B; B29; B29C; B29C70/00; B29C70/04; B29C70/06; B29C70/10; Y; Y10; Y10S; Y10S525/00; Y10S525/935; Y10T; Y10T428/00; Y10T428/249921; Y10T428/29; Y10T428/2913; Y10T428/2916; Y10T428/2918; Y10T428/2933; Y10T428/294; Y10T428/2973; Y10T428/2976; Y10T442/00; Y10T442/60; Y10T442/608; Y10T442/609; Y10T442/61
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
127 words
In a reinforced plastic matrix of improved mechanical strength, having embedded therein reinforcing fibers, an improved reinforcing fiber characterized by: a diameter variation along its axis producing alternate lengths of large diameter and small diameter wherein the axial distance from the smallest to the largest diameter of the fiber is 2 to 5 times the diameter variation to produce a socket in the matrix corresponding to the large diameter and small diameter lengths of the fiber, the small diameter socket locking the large diameter length of the fiber in the large diameter socket; and the alternating large and small diameter lengths of the fiber forming a smoothly undulating contour free of sudden changes in diameter to minimize areas of stress concentration in the fiber under axial tension.
Claim 2
Dependent Claim
127 words
In a reinforced plastic matrix of improved mechanical strength, having embedded therein reinforcing fibers, an improved reinforcing fiber characterized by: a diameter variation along its axis producing alternate lengths of large diameter and small diameter wherein the axial distance from the smallest to the largest diameter of the fiber is 2 to 5 times the diameter variation to produce a socket in the matrix corresponding to the large diameter and small diameter lengths of the fiber, the small diameter socket locking the large diameter length of the fiber in the large diameter socket; and the alternating large and small diameter lengths of the fiber forming a smoothly undulating contour free of sudden changes in diameter to minimize areas of stress concentration in the fiber under axial tension.
Claim 3
Dependent Claim
114 words
A reinforced plastic structure comprising fibers embedded in a plastic matrix in which the fibers have variations in diameter along the fibers axis, the diameter variations forming alternating lengths of large diameter and lengths of small diameter wherein the axial distance from the smallest to the largest diameter of the fiber is 2 to 5 times the diameter variation resulting in a smoothly undulating contour, free of sudden changes in diameter, a cavity in the plastic matrix conforming to the contour of the fiber, the large diameter lengths of the fiber mechanically locked in the large diameter cavity of the matrix by the small diameter lengths of the cavity to increase fiber pull-out energy.
Claim 4
Dependent Claim
114 words
A reinforced plastic structure comprising fibers embedded in a plastic matrix in which the fibers have variations in diameter along the fibers axis, the diameter variations forming alternating lengths of large diameter and lengths of small diameter wherein the axial distance from the smallest to the largest diameter of the fiber is 2 to 5 times the diameter variation resulting in a smoothly undulating contour, free of sudden changes in diameter, a cavity in the plastic matrix conforming to the contour of the fiber, the large diameter lengths of the fiber mechanically locked in the large diameter cavity of the matrix by the small diameter lengths of the cavity to increase fiber pull-out energy.
Claim 5
Dependent Claim
40 words
The reinforced plastic matrix of claim 1 in which the variation of diameter lengths of the fiber is from 20% to 40 of the average diameter of the fiber and a wavelength of 2 to 5 times the diameter variation.
Claim 6
Dependent Claim
28 words
The reinforced plastic matrix of claim 1 in which the fiber composition is selected from the group consisting of glass, synthetic high polymers, graphite, boron, ceramics, and metals.
References Cited (Backward Citations)
US3185613A
Cited
US3098723A
Cited
US3567569A
Cited
US3592727A
Cited
US3592272A
Cited
US3876389A
Cited
US4036599A
Cited
US4059950A
Cited
US4291096A
Cited
US4233364A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-03 | 1989-09-02 | 1990-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-03 | 1993-09-02 | 1994-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-03 | 1997-09-02 | 1998-03-04 | $7700.00 | Window Closed / Lapsed |