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Patent US4668557A successfully refreshed from Google Patents.
US4668557A
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Polyhedron cell structure and method of making same
Assignee: University of Iowa Research Foundation
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Filing: 1986-07-18
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Granted: 1987-05-26
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Expires: 2006-07-18
Abstract
Abstract An open cell foam structure that has a negative Poisson's ratio. Structure can be created by triaxially compressing a conventional open-cell foam material and heating the compressed structure beyond the softening point to produce a permanent deformation in the structure of the material. The structure thus produced has cells whose ribs protrude into the cell resulting in unique properties for materials of this type.
Inventors
- 👤 Roderic S. Lakes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:18
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/56; B29C44/5627; B29C44/35; B29C44/355; B29C44/357; B29C44/5636; C; C08; C08J; C08J9/00; C08J9/36; B29K; B29K2105/00; B29K2105/04; B29K2105/045; Y; Y10; Y10S; Y10S521/00; Y10S521/918; Y10T; Y10T428/00; Y10T428/24; Y10T428/24273; Y10T428/249921; Y10T428/249953; Y10T428/249962; Y10T428/249967; Y10T428/24997; Y10T428/249975
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
110 words
The method of making a composition of matter having a negative Poisson's ratio comprising the steps of producing a starting material having an open-cell foam structure with each cell being defined by a plurality of ribs; applying sufficient force to the starting material in each of three orthogonal directions simultaneously to compress the ribs of the cells inwardly; raising the temperature of the material above the softening temperature of the material while maintaining the material in the compressed state; cooling the material below the softening temperature while continuing to maintain the material in the compressed state: and releasing the applied force once the material has cooled below the softening temperature.
Claim 2
Independent Claim
110 words
The method of making a composition of matter having a negative Poisson's ratio comprising the steps of producing a starting material having an open-cell foam structure with each cell being defined by a plurality of ribs; applying sufficient force to the starting material in each of three orthogonal directions simultaneously to compress the ribs of the cells inwardly; raising the temperature of the material above the softening temperature of the material while maintaining the material in the compressed state; cooling the material below the softening temperature while continuing to maintain the material in the compressed state: and releasing the applied force once the material has cooled below the softening temperature.
Claim 3
Dependent Claim
20 words
The method of claim 1 in which the starting material is an open-cell foam structure which has a low density.
Claim 4
Dependent Claim
15 words
The method of claim 2 in which the starting material is an open-cell isotropic structure.
Claim 5
Dependent Claim
14 words
A material having a negative Poisson's ratio produced by the method of claim 1.
Claim 6
Independent Claim
40 words
A method of making an open-cell isotropic material having a negative Poisson's ratio comprising the steps of restraining the material from three orthogonal directions during the formation of the material and allowing the material to cool while maintaining the restraint.
Claim 7
Independent Claim
40 words
A method of making an open-cell isotropic material having a negative Poisson's ratio comprising the steps of restraining the material from three orthogonal directions during the formation of the material and allowing the material to cool while maintaining the restraint.
Claim 8
Dependent Claim
14 words
A material having a negative Poisson's ratio produced by the method of claim 5.
Claim 9
Dependent Claim
30 words
An isotropic open-cell material having a negative Poisson's ratio, said material comprising a plurality of interconnected spaced-apart ribs defining a plurality of cells, the ribs in the cells protruding inwardly.
Claim 10
Dependent Claim
30 words
An isotropic open-cell material having a negative Poisson's ratio, said material comprising a plurality of interconnected spaced-apart ribs defining a plurality of cells, the ribs in the cells protruding inwardly.
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) | 1990-05-25 | 1990-11-24 | 1991-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-25 | 1994-11-24 | 1995-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-25 | 1998-11-24 | 1999-05-26 | $7700.00 | Window Closed / Lapsed |