US5238734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Railroad ties made of recycled tire fragments
Assignee: RECYCLING SYSTEMS
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Filing: 1992-03-09
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Granted: 1993-08-24
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Expires: 2012-03-09
Abstract
Abstract This invention relates to the use of rubber fragments from discarded tires in railroad ties. Such ties are made using rubber fragments which contain steel, polyester, or other strands or fibers, and which therefor are less expensive to prepare than fragments from which the reinforcing strands have been removed. These fragments are mixed with an epoxy mixture comprising an oxirane-containing resin and an amine-containing hardening agent. Test samples made using the materials described herein have excellent hardness, strength, durability, and nail-gripping characteristics.
Inventors
- 👤 Kevin N. Murray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:04
CPC Classifications
B; B29; B29B; B29B17/00; B29B17/04; B29B17/0026; B29B17/0042; C; C08; C08L; C08L19/00; C08L19/003; E; E01; E01B; E01B3/00; E01B3/44; E01F; E01F1/00; E01F8/00; E01F8/02; E01F8/021; E01F8/024; B29K; B29K2021/00; B29K2063/00; B29L; B29L2030/00; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/62; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249924; Y10T428/249933; Y10T428/249953; Y10T428/249982
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
81 words
A molded railroad tie having sufficient strength and durability to render it suitable for prolonged use beneath a railroad track, constructed of rubber fragments mixed with an epoxy adhesive and bonded together, the rubber fragments being produced by fragmenting rubber-containing tires, wherein strands of steel and other reinforcing materials present in the tires have not been removed, and wherein the molded railroad tie is formed under pressure in a mold for a time period sufficient for the epoxy adhesive to set.
Claim 2
Dependent Claim
81 words
A molded railroad tie having sufficient strength and durability to render it suitable for prolonged use beneath a railroad track, constructed of rubber fragments mixed with an epoxy adhesive and bonded together, the rubber fragments being produced by fragmenting rubber-containing tires, wherein strands of steel and other reinforcing materials present in the tires have not been removed, and wherein the molded railroad tie is formed under pressure in a mold for a time period sufficient for the epoxy adhesive to set.
Claim 3
Dependent Claim
27 words
The molded railroad tie of claim 1 wherein the epoxy adhesive comprises, as one component, a resin compound containing molecules having two or more oxirane reactive groups.
Claim 4
Dependent Claim
23 words
The molded railroad tie of claim 2 wherein the resin compound comprises bis-phenol groups in spacer chains positioned between the oxirane reactive groups.
Claim 5
Dependent Claim
22 words
The molded railroad tie of claim 2 wherein the hardener compound contains molecules having two or more reactive amino groups per molecule.
Claim 6
Dependent Claim
33 words
The molded railroad tie of claim 1 wherein the rubber fragments are blended with the adhesive in a ratio of one part epoxy to about four to eight parts rubber particles, by weight.
Claim 7
Dependent Claim
23 words
The molded railroad tie of claim 1, containing strips of rubber incorporated therein which are sufficiently long to provide reinforcement against tensile stresses.
Claim 8
Dependent Claim
26 words
The molded railroad tie of claim 1, containing fibrous material incorporated therein with strands of material that are sufficiently long to provide reinforcement against tensile stresses.
Claim 9
Dependent Claim
55 words
A molded railroad tie having sufficient strength and durability to render it suitable for prolonged use beneath a railroad track, constructed of rubber fragments mixed with an epoxy adhesive and bonded together, wherein the epoxy adhesive somprises the residue of a resin compound containing oxirane reactive groups and a hardener compound containing amine reactive groups.
Claim 10
Dependent Claim
55 words
A molded railroad tie having sufficient strength and durability to render it suitable for prolonged use beneath a railroad track, constructed of rubber fragments mixed with an epoxy adhesive and bonded together, wherein the epoxy adhesive somprises the residue of a resin compound containing oxirane reactive groups and a hardener compound containing amine reactive groups.
References Cited (Backward Citations)
US2892592A
Cited
US2977864A
Cited
US3081035A
Cited
US3801421A
Cited
GB1586882A
Cited
US4244841A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-23 | 1997-02-22 | 1997-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-23 | 2001-02-22 | 2001-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-23 | 2005-02-22 | 2005-08-24 | $7700.00 | Window Closed / Lapsed |