Patent US4662777A successfully refreshed from Google Patents.
US4662777A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite article
Assignee: Individual
•
Filing: 1984-11-21
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Granted: 1987-05-05
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Expires: 2004-11-21
Abstract
Abstract A composite cover 10 for a manhole or other opening comprises an upper 12 and lower 14 skin of glass reinforced plastics material. The upper and lower skins are bonded to one another about the edges 18 and spaced apart from one another therebetween to define a space 16 containing reinforcing walls 20 extending between the upper 12 and lower 14 skins. The reinforcing walls 20 are preferably formed from a corrugated sheet of glass fibre reinforced plastics material. The cover of the invention is as strong as conventional cast iron covers but is lighter and cheaper to manufacture.
Inventors
- 👤 John R. Newton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:08
CPC Classifications
E; E02; E02D; E02D29/00; E02D29/12; E02D29/124; E02D29/14; F; F16; F16L; F16L59/00; F16L59/04; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149; Y10T428/24157; Y10T428/24628; Y10T428/24661
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
A composite cover having high loadbearing capacity, comprising an upper and a lower skin of fiber reinforced thermosetting resin 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 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 infills of plastic foam material, and the skins and reinforcing walls being resin impregnated so as to form one solid integral unit substantially free of joints or seams and the upper skin is provided with a gel coat which carries a non-slip pattern and has antistatic properties.
Claim 2
Dependent Claim
133 words
A composite cover having high loadbearing capacity, comprising an upper and a lower skin of fiber reinforced thermosetting resin 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 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 infills of plastic foam material, and the skins and reinforcing walls being resin impregnated so as to form one solid integral unit substantially free of joints or seams and the upper skin is provided with a gel coat which carries a non-slip pattern and has antistatic properties.
Claim 3
Dependent Claim
16 words
A cover as claimed in claim 1 wherein the fiber reinforcement comprises a glass fiber material.
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
19 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
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 8
Dependent Claim
54 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, and 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 9
Dependent Claim
37 words
A cover as claimed in claim 7 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 10
Dependent Claim
27 words
A cover as claimed in claim 7 wherein the housing contains a stop abutment for the key so that the key may lock in its lifting position.
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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) | 1990-05-04 | 1990-11-03 | 1991-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-04 | 1994-11-03 | 1995-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-04 | 1998-11-03 | 1999-05-05 | $7700.00 | Window Closed / Lapsed |