US4100248A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of grading and dewatering screens
Assignee: Birtley Engineering Ltd
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Filing: 1976-11-04
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Granted: 1978-07-11
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Expires: 1996-11-04
Abstract
Abstract An element for use in forming a deck for a grading or dewatering screen is formed by casting an elastomeric material such as polyurethane into a mould so that a smooth sheet of the material is formed in a liquid state in the mould, lowering into the liquid elastomeric material a substantially rigid open-work reinforcement, such as a perforated metal plate, and an array of studs for forming apertures in the screen element, the studs extending through the openings of the reinforcement and through the elastomeric material substantially to the bottom of the mould, allowing the elastomeric material to set, and then withdrawing the studs from the set sheet of elastomeric material. This provides a screen element comprising a sheet of elastomeric material having a rigid reinforcement embedded therein and a plurality of grading or dewatering apertures extending through the elastomeric sheet, the apertures being aligned with the openings in the reinforcement. Preferably the reinforcement has projections, such as flanges, extending substantially perpendicularly from it and from the rear face of the elastomeric sheet on at least two opposite edges of the element.
Inventors
- 👤 Terence C. Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:47
CPC Classifications
B; B29; B29D; B29D28/00; B29D28/005; B01; B01D; B01D29/00; B01D29/01; B01D29/012; B01D29/03; B01D29/11; B01D29/111; B01D29/31; B01D29/35; B01D29/44; B07; B07B; B07B1/00; B07B1/46; B07B1/4609; B07B1/4618; B07B1/4645; B29C; B29C39/00; B29C39/003; B29C39/006; B29C39/02; B29C39/10; Y; Y10; Y10S; Y10S162/00; Y10S162/903; Y10S264/00; Y10S264/70
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
150 words
A method of making a reinforced elastomeric apertured screen element for a grading or dewatering screen, comprising the steps of providing a tray-like mould having a substantially horizontal bottom and upright side walls, forming in said mould a sheet of a wear resistant elastomeric material in a liquid state, providing above said mould both a plurality of studs for forming the apertures of the screen element and a substantially rigid open-work reinforcement defining a plurality of openings therein, lowering said reinforcement into contact with said liquid elastomeric material in said mould, lowering said studs whereby said studs penetrate said liquid elastomeric material substantially to said bottom of said mould, said studs extending through said openings of said reinforcement, allowing said liquid elastomeric material to set, and withdrawing said studs from the set sheet of said elastomeric material in said mould leaving said reinforcement and said elastomeric material permanently fixed together.
Claim 2
Independent Claim
150 words
A method of making a reinforced elastomeric apertured screen element for a grading or dewatering screen, comprising the steps of providing a tray-like mould having a substantially horizontal bottom and upright side walls, forming in said mould a sheet of a wear resistant elastomeric material in a liquid state, providing above said mould both a plurality of studs for forming the apertures of the screen element and a substantially rigid open-work reinforcement defining a plurality of openings therein, lowering said reinforcement into contact with said liquid elastomeric material in said mould, lowering said studs whereby said studs penetrate said liquid elastomeric material substantially to said bottom of said mould, said studs extending through said openings of said reinforcement, allowing said liquid elastomeric material to set, and withdrawing said studs from the set sheet of said elastomeric material in said mould leaving said reinforcement and said elastomeric material permanently fixed together.
Claim 3
Dependent Claim
28 words
A method as claimed in claim 1, wherein said reinforcement is completely enveloped in said liquid elastomeric material whereby said reinforcement is embedded in said set elastomeric sheet.
Claim 4
Dependent Claim
19 words
A method as claimed in claim 1, wherein said studs are each tapered towards said bottom of said mould.
Claim 5
Dependent Claim
54 words
A method as claimed in claim 1, wherein said studs and said reinforcement are provided above said mould with said studs being supported by said reinforcement and extending through said openings of said reinforcement, and wherein said reinforcement and said studs are simultaneously lowered into contact with said liquid elastomeric material in said mould.
Claim 6
Dependent Claim
95 words
A method as claimed in claim 4, wherein said studs are each tapered towards said bottom of said mould and are supported by said reinforcement by contact with the edges of said openings of said reinforcement at spaced points around the peripheries of said studs, and wherein the method includes the further step of moving said reinforcement further into said mould relative to said studs after said studs have penetrated to said bottom of said mould whereby said studs disengage from said edges of said reinforcement openings and said liquid elastomeric material envelopes said reinforcement.
Claim 7
Dependent Claim
19 words
A method as claimed in claim 1 wherein said reinforcement is in the form of a perforated metal plate.
Claim 8
Dependent Claim
71 words
A method as claimed in claim 1, wherein said reinforcement is provided with projections extending substantially perpendicularly from said reinforcement and from the exposed face of said elastomeric material in said mould adjacent at least two opposite side walls of said mould, and wherein the method includes the step of holding said reinforcement in a predetermined position relative to said mould while said elastomeric material sets by means engaging said projections.
Claim 9
Dependent Claim
26 words
A method as claimed in claim 7, wherein said mould is substantially rectangular and said reinforcement has projections adjacent all four side walls of said mould.
Claim 10
Dependent Claim
51 words
A method as claimed in claim 8, wherein said reinforcement is in the form of a perforated metal plate, and wherein said projections are provided by flanges formed integrally from said reinforcement plate, each of said flanges extending along substantially the whole length of the corresponding edge of said reinforcement plate.
Claim 11
Dependent Claim
25 words
A method as claimed in claim 1, wherein said studs are shaped to produce apertures in said elastomeric sheet in the form of narrow slots.
Claim 12
Dependent Claim
33 words
A method as claimed in claim 10, wherein said slots produced by said studs are between 0.1 and 1.0 mms wide at the face of said sheet adjacent said bottom of said mould.
Claim 13
Dependent Claim
36 words
A method as claimed in claim 10, wherein said studs project from a plurality of parallel blades extending in the longitudinal direction of said studs, each of said blades carrying a longitudinal row of said studs.
Claim 14
Dependent Claim
30 words
A method as claimed in claim 1, wherein each of said studs penetrates into said elastomeric material in said mould through a different one of said openings in said reinforcement.
Claim 15
Dependent Claim
37 words
A method as claimed in claim 1, including the step of coating said studs and the inside of said mould with a release agent which inhibits bonding of said elastomeric material to said studs and said mould.
Claim 16
Dependent Claim
57 words
A method as claimed in claim 1, including the step of forming a thin and even layer of waxy material over said bottom of said mould before said sheet of liquid elastomeric material is formed in said mould, said waxy material being solid at the temperature at which said liquid elastomeric material is cast in said mould.
Claim 17
Dependent Claim
28 words
A method as claimed in claim 1, wherein said studs are withdrawn from said set sheet of elastomeric material in said mould while said elastomeric material is hot.
Claim 18
Dependent Claim
37 words
A method as claimed in claim 16, wherein, before said studs are withdrawn, said set sheet of elastomeric material is heated to between 10° and 20° C higher than the temperature at which said elastomeric material set.
Claim 19
Dependent Claim
14 words
A method as claimed in claim 1, wherein said elastomeric material is a polyurethane.
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) | 1981-07-10 | 1982-01-09 | 1982-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-10 | 1986-01-09 | 1986-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-10 | 1990-01-09 | 1990-07-11 | $7700.00 | Window Closed / Lapsed |