Patent US4875798A successfully refreshed from Google Patents.
US4875798A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Retroreflective pavement marker
Assignee: 3M Co
•
Filing: 1988-06-30
•
Granted: 1989-10-24
•
Expires: 2008-06-30
Abstract
Abstract A raised retroreflective pavement marker that provides both improved retroreflectivity and longer life has a rigid opaque, synthetic resin body having at its front face septa to which a plastic cube-corner reflector has been bonded to provide a plurality of hermetically sealed cells beneath the reflector. This pavement marker differs from those on the market in that the thickness of its reflector is less than 2 mm, and it has preferably at least 500 cube-corner elements per cm 2 .
Inventors
- 👤 David C. May
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 02:45
CPC Classifications
E; E01; E01F; E01F9/00; E01F9/50; E01F9/553
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
131 words
Raised pavement marker comprising a substantially rigid body having a bottom surface, at least one sloped face, septa projecting from said sloped face, and a plastic cube-corner reflector, having at least 500 cube-corner elements per cm 2 formed by intersecting sets of parallel grooves, bonded to the septa to provide a plurality of cells beneath the reflector, the depth of which is sufficient that cube corners of the reflector between the septa do not contact the body when the pavement marker is adhered to a roadway and subjected to vehicular impact, said pavement marker being characterized by: the exposed face of the reflector forming an angle of from 15° to 45° to the surface of the roadway and the overall thickness of the cube corner reflector being less than 2 mm.
Claim 2
Dependent Claim
131 words
Raised pavement marker comprising a substantially rigid body having a bottom surface, at least one sloped face, septa projecting from said sloped face, and a plastic cube-corner reflector, having at least 500 cube-corner elements per cm 2 formed by intersecting sets of parallel grooves, bonded to the septa to provide a plurality of cells beneath the reflector, the depth of which is sufficient that cube corners of the reflector between the septa do not contact the body when the pavement marker is adhered to a roadway and subjected to vehicular impact, said pavement marker being characterized by: the exposed face of the reflector forming an angle of from 15° to 45° to the surface of the roadway and the overall thickness of the cube corner reflector being less than 2 mm.
Claim 3
Dependent Claim
17 words
Raised pavement marker as defined in claim 1, wherein each cell contains a plurality of cube-corner elements.
Claim 4
Dependent Claim
22 words
Raised pavement marker as defined in claim 2, the reflector of which has at least 1000 cube-corner elements per cm 2 .
Claim 5
Dependent Claim
20 words
Raised pavement marker as defined in claim 1 wherein the overall thickness of the reflector is at least 0.5 mm.
Claim 6
Dependent Claim
21 words
Raised pavement marker as defined in claim 4 wherein the overall thickness of the reflector is from 1.0 to 1.5 mm.
Claim 7
Dependent Claim
33 words
Raised pavement marker as defined in claim 1 wherein the reflector is a thermoplastic resin having an impact resistance of at least 16 J/cm and a flexural modulus of at least 1400 MPa.
Claim 8
Dependent Claim
22 words
Raised pavement marker as defined in claim 1 wherein the septa contact from 10 to 70% of the area of the reflector.
Claim 9
Dependent Claim
22 words
Raised pavement marker as defined in claim 7 wherein the septa between the cells have substantially uniform width of about 1 mm.
Claim 10
Dependent Claim
19 words
Raised pavement marker as defined in claim 7 wherein the septa have a uniform height of about 1.25 mm.
Claim 11
Dependent Claim
42 words
Raised pavement marker as defined in claim 1, the body of which comprises a plurality of vertical partitions that extend the full width of the pavement marker and are interconnected by webs to form honeycomb recesses that open through its bottom surface.
Claim 12
Dependent Claim
19 words
Raised pavement marker as defined in claim 10 wherein said webs are staggered in the direction of vehicular travel.
References Cited (Backward Citations)
US3332327A
Cited
US3392639A
Cited
US3924929A
Cited
US3409344A
Cited
US4208090A
Cited
US3485148A
Cited
US3627403A
Cited
US4070095A
Cited
US4349598A
Cited
US4227772A
Cited
US4232979A
Cited
US4428320A
Cited
US4498733A
Cited
US4588258A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-23 | 1993-04-24 | 1993-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-23 | 1997-04-24 | 1997-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-23 | 2001-04-24 | 2001-10-24 | $7700.00 | Window Closed / Lapsed |