US4661387A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steel materials for use with prestressed concrete
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1984-12-14
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Granted: 1987-04-28
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Expires: 2004-12-14
Abstract
Abstract A prestressing steel material for use with concrete that is prestressed by posttensioning is disclosed. Said steel material is unbonded from the concrete. The prestressing steel material is composed of a steel member sheathed with a foamed synthetic resin tube. The wall thickness of the synthetic resin tube is at least 300 microns, more preferably, more than 500 microns. In the case that the steel member is a strand composed of a plurality of twisted steel wires, the spiral grooves of the strand are first filled with a resin and the strand together with the resin sheathed with the foamed synthetic resin tube.
Inventors
- 👤 Kanji Watanabe
- 👤 Mikio Mizoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:11
CPC Classifications
D; D07; D07B; D07B1/00; D07B1/16; D07B1/162; E; E04; E04C; E04C5/00; E04C5/08; D07B2201/00; D07B2201/20; D07B2201/2015; D07B2201/2042; D07B2201/2044; D07B2201/2045; D07B2501/00; D07B2501/20; D07B2501/2015; D07B2501/2023; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/131; Y10T428/1317; Y10T428/1321; Y10T428/1352; Y10T428/1355; Y10T428/249921; Y10T428/249953; Y10T428/249955; Y10T428/249958; Y10T428/249987; Y10T428/24999; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/294; Y10T428/2942; Y10T428/2947
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
33 words
An elongated prestressing steel material embedded in prestressed concrete, comprising: an elongated ungreased steel member, and a foamed synthetic resin tube sheathing bonded to said steel member and not bonded to said concrete.
Claim 2
Dependent Claim
33 words
An elongated prestressing steel material embedded in prestressed concrete, comprising: an elongated ungreased steel member, and a foamed synthetic resin tube sheathing bonded to said steel member and not bonded to said concrete.
Claim 3
Dependent Claim
19 words
The prestressing steel material of claim 1, wherein a wall thickness of said tube is at least 300 microns.
Claim 4
Dependent Claim
19 words
The prestressing steel material of claim 1, wherein a wall thickness of said tube is at least 500 microns.
Claim 5
Dependent Claim
16 words
The prestressing steel material of claim 1, wherein said synthetic resin is a foamed polyethylene tube.
Claim 6
Dependent Claim
32 words
The prestressing steel material of claim 1, wherein said synthetic resin tube is formed by applying a synthetic resin powder containing a blowing agent to a surface of a preheated steel member.
Claim 7
Dependent Claim
45 words
The prestressing steel material of claim 1, wherein said synthetic resin tube is formed by applying a film of synthetic resin containing a blowing agent to a surface of said steel member and then heating said steel member to expand said resin into a foam.
Claim 8
Dependent Claim
54 words
An elongated ungreased prestressing steel material embedded in prestressed concrete, comprising: a steel strand having a plurality of twisted steel wires, said steel strand having a plurality of spiral grooves formed therein; a resin filling said grooves; and a foamed synthetic resin tube sheathing bonded to said strand and not bonded to said concrete.
Claim 9
Dependent Claim
54 words
An elongated ungreased prestressing steel material embedded in prestressed concrete, comprising: a steel strand having a plurality of twisted steel wires, said steel strand having a plurality of spiral grooves formed therein; a resin filling said grooves; and a foamed synthetic resin tube sheathing bonded to said strand and not bonded to said concrete.
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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) | 1990-04-27 | 1990-10-27 | 1991-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-27 | 1994-10-27 | 1995-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-27 | 1998-10-27 | 1999-04-28 | $7700.00 | Window Closed / Lapsed |