US4726707A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite article
Assignee: Individual
•
Filing: 1987-02-19
•
Granted: 1988-02-23
•
Expires: 2007-02-19
Abstract
Abstract A composite cover having high load-bearing capacity comprising an upper and a lower skin of fiber-reinforced plastic material, the upper and lower skins being integral with one another around the edges of the cover and spaced apart from one another therebetween, the space so formed containing reinforcing walls of fiber-reinforced plastic material extending between the upper and lower skins, the reinforcing walls being integral with the upper and lower skins where they contact the same, the voids between the reinforcing walls being filled with lightweight infills, and the skins and reinforcing walls being resin impregnated so as to form one solid integral unit substantially free of joints or seams.
Inventors
- 👤 John R. Newton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:45
CPC Classifications
E; E02; E02D; E02D29/00; E02D29/12; E02D29/14; E02D29/1445; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149; Y10T428/24157; Y10T428/24628; Y10T428/24661
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
129 words
A composite cover having high load-bearing capacity, comprising an upper and a lower skin of fiber-reinforced plastic material comprising glass fibers, the upper and lower skins being integral with one another around the edges of the cover and spaced apart from one another therebetween, the space so formed containing reinforcing walls of fiber-reinforced plastic material extending between the upper and lower skins, the reinforcing walls being integral with the upper and lower skins where they contact the same, the voids between the reinforcing walls being filled with lightweight infills, and the skins and reinforcing walls being resin impregnated so as to form one solid integral unit substantially free of joints or seams, said cover having a glass fiber content in the range of from approximately 40% to approximately 62%.
Claim 2
Dependent Claim
129 words
A composite cover having high load-bearing capacity, comprising an upper and a lower skin of fiber-reinforced plastic material comprising glass fibers, the upper and lower skins being integral with one another around the edges of the cover and spaced apart from one another therebetween, the space so formed containing reinforcing walls of fiber-reinforced plastic material extending between the upper and lower skins, the reinforcing walls being integral with the upper and lower skins where they contact the same, the voids between the reinforcing walls being filled with lightweight infills, and the skins and reinforcing walls being resin impregnated so as to form one solid integral unit substantially free of joints or seams, said cover having a glass fiber content in the range of from approximately 40% to approximately 62%.
Claim 3
Dependent Claim
25 words
A cover as defined in claim 1 wherein the glass fiber content of the cover is within the range from about 50% to about 62%.
Claim 4
Dependent Claim
23 words
A cover as claimed in claim 1 wherein the reinforcing walls comprise the vertical wall portions of a corrugated sheet of reinforcing material.
Claim 5
Dependent Claim
18 words
A cover as claimed in claim 1 wherein the infills are comprised of a closed-celled polyurethane foam material.
Claim 6
Dependent Claim
24 words
A cover as claimed in claim 1 wherein the under surfaces of the edges of the cover are downwardly inclined and carry wear pads.
Claim 7
Dependent Claim
58 words
A cover as claimed in claim 1 further comprising a keyhole formed in a housing fitted within the cover between the upper and lower skins, the keyhole adapted to receive a corresponding key having an elongate handle so as to reduce the need for bending when lifting the cover by means of the key inserted in the keyhole.
Claim 8
Dependent Claim
37 words
A cover as claimed in claim 6 wherein the keyhole housing comprises a metal casting removably inserted within a tapered hole formed in the cover locked in place by means of a sealed ring and swaged thereto.
Claim 9
Dependent Claim
27 words
A cover as claimed in claim 6 wherein the housing contains a stop abutment for the key so that the key may lock in its lifting position.
Claim 10
Dependent Claim
29 words
A cover as claimed in claim 1 wherein a top surface of the cover is provided with a gel coat which carries a non-slip pattern and has antistatic properties.
Claim 11
Dependent Claim
29 words
A cover as claimed in claim 1 further comprising guide portions formed on the cover to locate the cover in its opening and guide the cover when being removed.
Claim 12
Independent Claim
89 words
A method of forming a composite cover having load-bearing capacity, comprising the steps of: laying a bottom skin of fiber reinforcing material; placing walls and infills on the bottom skin; covering the walls and infills with a top skin of fiber-reinforcing material; and placing the resulting assembly into a mold and injecting resin into the mold so as to impregnate the fiber-reinforcing material and form a solid integral unit substantially free of joints or seams having a fiber content in the range of from approximately 40% to approximately 62%.
Claim 13
Independent Claim
89 words
A method of forming a composite cover having load-bearing capacity, comprising the steps of: laying a bottom skin of fiber reinforcing material; placing walls and infills on the bottom skin; covering the walls and infills with a top skin of fiber-reinforcing material; and placing the resulting assembly into a mold and injecting resin into the mold so as to impregnate the fiber-reinforcing material and form a solid integral unit substantially free of joints or seams having a fiber content in the range of from approximately 40% to approximately 62%.
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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) | 1991-02-22 | 1991-08-24 | 1992-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-22 | 1995-08-24 | 1996-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-22 | 1999-08-24 | 2000-02-23 | $7700.00 | Window Closed / Lapsed |