CA1222157A - Sheet material marker surface for roadways and the like - Google Patents
Sheet material marker surface for roadways and the likeInfo
- Publication number
- CA1222157A CA1222157A CA000420753A CA420753A CA1222157A CA 1222157 A CA1222157 A CA 1222157A CA 000420753 A CA000420753 A CA 000420753A CA 420753 A CA420753 A CA 420753A CA 1222157 A CA1222157 A CA 1222157A
- Authority
- CA
- Canada
- Prior art keywords
- strip
- wedges
- indicating
- wedge
- marker
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000003550 marker Substances 0.000 title claims abstract description 45
- 239000000463 material Substances 0.000 title claims abstract description 16
- 239000011324 bead Substances 0.000 claims description 18
- 239000010410 layer Substances 0.000 claims description 6
- 238000005299 abrasion Methods 0.000 claims description 4
- 239000000853 adhesive Substances 0.000 claims description 4
- 230000001070 adhesive effect Effects 0.000 claims description 4
- 229920002457 flexible plastic Polymers 0.000 claims description 4
- 229920003023 plastic Polymers 0.000 claims description 4
- 230000001154 acute effect Effects 0.000 claims description 2
- 239000002344 surface layer Substances 0.000 claims 2
- 239000000727 fraction Substances 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 5
- 238000000926 separation method Methods 0.000 abstract 1
- 238000010276 construction Methods 0.000 description 7
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 229920001944 Plastisol Polymers 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 230000009975 flexible effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 239000004005 microsphere Substances 0.000 description 2
- 239000004999 plastisol Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 239000003981 vehicle Substances 0.000 description 2
- 241000534944 Thia Species 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000010426 asphalt Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 230000002844 continuous effect Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
- E01F9/00—Arrangement of road signs or traffic signals; Arrangements for enforcing caution
- E01F9/50—Road surface markings; Kerbs or road edgings, specially adapted for alerting road users
- E01F9/576—Traffic lines
- E01F9/578—Traffic lines consisting of preformed elements, e.g. tapes, block-type elements specially designed or arranged to make up a traffic line
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Road Signs Or Road Markings (AREA)
Abstract
SHEET MATERIAL MARKER SURFACE FOR
ROADWAYS AND THE LIKE
Abstract This disclosure involves an improved thin surface-marking strip for adhering to a traveling surface or the like, employing novel flattened somewhat saw-tooth wedges embodying retroreflective material and of preferably substantially trapezoidal shape, with rather critical separations between wedges relative to height and length of the wedges to obviate shadow effects, provide improved daylight observation, and to increase effectiveness and life, particu-larly under conditions of rain-covered surfaces and snow removal.
ROADWAYS AND THE LIKE
Abstract This disclosure involves an improved thin surface-marking strip for adhering to a traveling surface or the like, employing novel flattened somewhat saw-tooth wedges embodying retroreflective material and of preferably substantially trapezoidal shape, with rather critical separations between wedges relative to height and length of the wedges to obviate shadow effects, provide improved daylight observation, and to increase effectiveness and life, particu-larly under conditions of rain-covered surfaces and snow removal.
Description
lZZZ15'7 .
SHEET MATERIAL MARJ~R SVRFACE FOR
~OADWAYS AND THE LI~E
Ihe present invention relates to the distinctive marking of the directions of travel on motoring highways, airports and other surfaces, with the aid of thin marker strips adhered to the traveling or other surfaces and embodying successive spaced wedges provided with retroreflective materials~
the invention being more particularly concerned with improved marker strips for such purposes.
Because of the extremely shallow angle that is made between an automobile headlamp and the roadway it illuminates, only a very small per-centage of the light is reflected back for use by the motorist. The problem is made even more severe by the fact that the road surface is usually quite flat with poor reflection characteristics, black asphalt being the worst road surface from thia viewpoint. Average road surface visibility with low beams for the automobile headlamps at night is ~: . 3 , . .
- ' . :
.
~ .
.
~22Z~57
SHEET MATERIAL MARJ~R SVRFACE FOR
~OADWAYS AND THE LI~E
Ihe present invention relates to the distinctive marking of the directions of travel on motoring highways, airports and other surfaces, with the aid of thin marker strips adhered to the traveling or other surfaces and embodying successive spaced wedges provided with retroreflective materials~
the invention being more particularly concerned with improved marker strips for such purposes.
Because of the extremely shallow angle that is made between an automobile headlamp and the roadway it illuminates, only a very small per-centage of the light is reflected back for use by the motorist. The problem is made even more severe by the fact that the road surface is usually quite flat with poor reflection characteristics, black asphalt being the worst road surface from thia viewpoint. Average road surface visibility with low beams for the automobile headlamps at night is ~: . 3 , . .
- ' . :
.
~ .
.
~22Z~57
-2-usually restricted to about 100 feet. Considerable improvement is made by painting a white stripe on the road surface~ but even this, with a freshly painted line, does not extend road surface visi-bility much beyond a couple of hundred feet. When the road surface is wet with rain, moreover, the visibility is drastically reduced even with a freshly painted line and does not extend more than a few tens of feet. The thin film of water which covers the road and paint surface acts like a mirror which reflects nearly all of the auto-mobile headlamps' li8ht away from the motorist.
Thus, during rainy weather at night, even though provided with a good white stripe, the road appears almost pitch black to the motorist--this being the ma~or reason why night driving in the rain is so treacherous.
The art has concluded that the only practical way to overcome this poor visibility is by means of raised pavement markers which liter-all~ ext~nd above the thin film of uater and - ' .
~, ' .
- . .
lZZZ157 ,i . I .
- . I
Thus, during rainy weather at night, even though provided with a good white stripe, the road appears almost pitch black to the motorist--this being the ma~or reason why night driving in the rain is so treacherous.
The art has concluded that the only practical way to overcome this poor visibility is by means of raised pavement markers which liter-all~ ext~nd above the thin film of uater and - ' .
~, ' .
- . .
lZZZ157 ,i . I .
- . I
-3- !
retroreflect light back to the motorist. While commonly used in certain regions of the nation, especially in sunny climates, they are seldom used in the snow regions because of the destructive effects of snowplows. Efforts have been made to ovércome this difficulty by designing a protectlve framework or ramp which literally guides the snow-plow blade up and over the marker with little damageT but the general inability of some of these , mar~ers to withstand the harsh treatment given by the snowplows has prevented the1r widespread adoption. Such special constructions, furthermore, are expensive and are therefore usually positioned quite far apart. In addition they are useful only at night when illuminated by automobile headlamps and are poorly visible, if at ali, by the motoring public during daylight hours, often requiring an additional or supplemental marker in the form of a painted line or a plastic line for daytime drivin~ , gu1danoe.
' i ' .
~ ' . . ~ ' . ' ' , ~;
, . ~ .
. . .
l~ZZlS7 _4_ -- The art has struggled for years, however, with a wide assortment of raised pavement ~arkers, -of one configuration or another, for the ma~or purpose of guiding the night-driving motorist.
The majority of these devices have little if any detectability or utility durin~ daylight hours and are thus confined to night-time conditions wherein the illumination from automobile headl~mps is redirected by means of internal reflection back upon itself, thereby to be observed by the operator of the vehicle. These devices often take the form of buttons or mounds containing retro-reflecting elements or surfaces. More recently, ramp-like configurations have been adopted in order to provide less hazard to the vehicles traveling over them, some devices, indeed, having ¦-special ramps, previously mentiohed~ to assist in guiding the blades of snowplows, hopefully without uprooting them. Such devices, as before explained, are costly and, of necessity, must be relatively widely spaced from one another along . ' ............................. ' .' ~ 1:
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i .. .
.
~, . .` :
....... ~.. . . . . .
lZ2Z157 s ......... .
the roadway surface, resulting in the disadvantage that, under headlamp illumination at night, al-though bright in appearance, these devices at best present only pinpoints of li~ht and not a con-tinuous and highly desirable solid line, nor even a semblance of a skip line. During dayli~ht con-ditions they are usually not observable at all by the motoring public at any distance.
In an effort to overcome some of the ¦
above and other disadvantages of such and related raised pavement markers, markers of relatively ¦
low profile have been proposed, such as those disclosed in U. S. Letters Patent Nos. 3,785,719,
retroreflect light back to the motorist. While commonly used in certain regions of the nation, especially in sunny climates, they are seldom used in the snow regions because of the destructive effects of snowplows. Efforts have been made to ovércome this difficulty by designing a protectlve framework or ramp which literally guides the snow-plow blade up and over the marker with little damageT but the general inability of some of these , mar~ers to withstand the harsh treatment given by the snowplows has prevented the1r widespread adoption. Such special constructions, furthermore, are expensive and are therefore usually positioned quite far apart. In addition they are useful only at night when illuminated by automobile headlamps and are poorly visible, if at ali, by the motoring public during daylight hours, often requiring an additional or supplemental marker in the form of a painted line or a plastic line for daytime drivin~ , gu1danoe.
' i ' .
~ ' . . ~ ' . ' ' , ~;
, . ~ .
. . .
l~ZZlS7 _4_ -- The art has struggled for years, however, with a wide assortment of raised pavement ~arkers, -of one configuration or another, for the ma~or purpose of guiding the night-driving motorist.
The majority of these devices have little if any detectability or utility durin~ daylight hours and are thus confined to night-time conditions wherein the illumination from automobile headl~mps is redirected by means of internal reflection back upon itself, thereby to be observed by the operator of the vehicle. These devices often take the form of buttons or mounds containing retro-reflecting elements or surfaces. More recently, ramp-like configurations have been adopted in order to provide less hazard to the vehicles traveling over them, some devices, indeed, having ¦-special ramps, previously mentiohed~ to assist in guiding the blades of snowplows, hopefully without uprooting them. Such devices, as before explained, are costly and, of necessity, must be relatively widely spaced from one another along . ' ............................. ' .' ~ 1:
` !
i .. .
.
~, . .` :
....... ~.. . . . . .
lZ2Z157 s ......... .
the roadway surface, resulting in the disadvantage that, under headlamp illumination at night, al-though bright in appearance, these devices at best present only pinpoints of li~ht and not a con-tinuous and highly desirable solid line, nor even a semblance of a skip line. During dayli~ht con-ditions they are usually not observable at all by the motoring public at any distance.
In an effort to overcome some of the ¦
above and other disadvantages of such and related raised pavement markers, markers of relatively ¦
low profile have been proposed, such as those disclosed in U. S. Letters Patent Nos. 3,785,719,
4,035,059 and 4,279,471~ These concepts, however, involved individual units which are still costly to manufacture and thus again must be used with i relatively wide spacing between units to achieve realistic operational and cost effectiveness.
A more suitable approach for obviating these problems has resided in the use of thin flex.ble shee-ine on which ls contalned a ser1es ..
_. . . . . . .
`.
~`-;' ', , , .
l~ZZ15q ' - . ^' of very low profile raised pavement markers as described, for example, in my earlier U. S.
Letters Patent ~os. 3,920,346: 4,040,760s and 4,069,787~ and in Patent Nos. 4,145,112~
4,182,548; and 4,236,788. With the exception of the constructions of my said Patent Nos. .
4,040,760 and 4,069,787, such sheet markers are dependent upon having the main body of the marker constructed so as to be transparent to light, rendering the devices subject to serious light ¦ -loss effects in use, caused by abrasion and ¦ -accumulated dirt. In my said earlier construc- j tions, embodying the use of somewhat saw-tooth successive wed~es carried by a thin road-attachable strip, while quite satisfactory operation can be attained, it has been found that shadow effects when heading into the sun, and modification of results after the wedges have experienced some wear, as from extended use and/or snowplow de-facement or the like, do not permit as effective marking in daylight, dusk or under other adverse conditions as may be desirable.
;
122Z157 ' .
-7- ` `
In the case of the successive wedges -of substantially trian~ular shape taught in my said Patent No. 4,040,760, for example, extended use revealed that under certain conditions of ambient daylight, the pavement marker became somewhat difficult for the motorist to observe.
In particular, if the ~arker strip is oriented in such a way that the motorist is heading in the general direction of the sun on a cloudless !
day, the contrast between the marker and the road surface is so low that the marker becomes diffi- ¦
cult to distinguish. During these conditions, ¦
the sun will cast a shadow of each wedge on the valley floor between the wedges. Those faces of the wedges observed bythe motorist~ furthermore, are all contained within the shadow and thus appear ¦
black, introducing great difficulty in distinguish-ing the marker from the dark road surface. Ihe appearance of blackness or the poor contrast !
between the marker and the road surface is at a peak when the sun is at a low angle on a cloudless day.
:; - !
I
, , . , .
- ' ' ` ` . i .
. ~
. . '. ` ` ` ` ` ., . .` "~`~
. .
~2~Z157 .
;. ~ It was fortuitously discovered that - by changing the saw^tooth shape from triangular to trapezoidal, but onl.y with appropriate wedge length tO successive wedge spacing, this problem was completely obviated, and simultaneous other marked advantages in greater wear-resistance and life under abrasion, including snowplowing, also followed. The flat tops of the now trapezoidal-shaped wedge, if of appropriate dimensions and spacing, reflect sunlight and reduce the wedge shadow effect admirably well.
An object of the present invention, accord-ingly, is to provide a new and improved marker structure that shall not be subject to the above and other disadvantages, but that can obviate shadow and discontinuous effects and provides a marked improvement in wear and use under adverse - environmental conditions.
An additional object of the invention is to provide a flexible sheet material pavement marker or the like which will be clearly visible ~' , ' ,9 . .
as à continuous line by ambient dayli~ht as well -as retroreflection from automobile headlamps at night, even during a heavy downpour of rain.
A further object is to provide a flex-ible sheet material pavement marker with a con-figuration and low profile sufficient to resist uprooting by normal snowplow action.
Still another object is to provide a highly visible highway marker for night driving with a long life and with good retroreflection characteristics maintained throughout such life.
A further ob~ect is to provide a novel marker of more general utility, as well.
Other and further objects are explained hereinafter and are more particularly pointed out in the appended claims.
In summary, however, the invention, from one of its aspects, contemplates in combination with a roadway surface and the like, a direction-indicating surface marker strip of-~+-S~R~
flexible plastic material adherable to said surtace `
`f:
.' , ' " '" ` ' ', ', 122i~157 by a thin layer of adhesive between the strip and the surface, the strip being intermittently deformed upward to provide successive transversely disposed wedges of sub-stantially trapezoidal shape in longitudinal section, each wedge having a substantially flat top surface bounded by upwardly and downwardly acute-angle inclining front and rear surfaces, the inclining surfaces being provided with embedded retroreflecting beads. Preferred details of construction and best mode embodiments are later set forth.
The invention will now be described with reference to the accompanyin~ drawings, Fig. 1 of which is a lonaitudinal sectional view of a preferred embodiment of the invention; and Fig. 2 is a similar view of a modification.
lZZZ157 `11~
Referring to Fi~. 1, the thin flexible plastic elongated road marker strip 1 is shown adhered by a bottom adhesive layer 4 to the road-way or other surface K. Suitable materials are described in my said earlier patents and are hereinafter discussed. As previously described, the somewhat saw-tooth wed~e construction i8 illustrated in the form of substantially trape-zoidal (in longitudinal section) wedge pro~ections T having a flat top surface 2 and bounded by up-wardly and downwardly inclining front and rear ridge sùrfaces 2' and 2", all extending trans-versely across the strip 1, and all preferably integrally formed from the thin plastic material of the strip 1, with the wedges intermittently deformed upward of the strip.
A preferred range of acute angles cC
of inclination (or downward slope) enable proper operation in ~se as hereinafter discussed. At least the upwardly and downwardly inclined sur-faces 2' and 2" carry a retroreflective bead ~
layer( 9 ~ or the like 3. ~-: . ' . .
~ ' ' . .' .
.
~ - ~
~Z2Z157 -12- j! ~
, - .
ith this construction, it has been discovered that, instead of observing an apparent extension of a portion of one wedge face continu-ously merging with the next succeeding wedge face portion and so on, as described in my earlier ¦;
patents, in the case of the trapezoidal wed6e of ¦:
Fig. 1, there is an interruption in the apparent .
merging wedge faces by the width of the flat top surface 2 of the trapezoidal wedge T. Considering daylight operation, including heading into the . .
sun, when this diffusely reflecting flat top sur- :
face 2 has the same apparent area as that observable .
portion of the wedge face which is in shadow, it has been found that the visual effect of the sun shadow becomes sufficien~ly reduced to permit the marker 1 to be readily visually distinguished from :
the road surface ~. This provides ~arker indica- ;
tion under such daylight or dusk considerations that previous constructions do not adequately ';
provide. Increasing the area would provide even better dayli~ht contra-t between the marker and ~' , '- ' ' ' ,' ,~. j:
' ~
lZZZ157 the road surface. but the apparent brightness of night time retroreflection from automobile headlamps would diminish. The condition for pro-ducing apparent equal areas is fulfilled when the width of the flat top surface 2 of the trape-zoidal wedge T is made about equal (comparable) to that of the valley floor 1' between successive wedges. It has also been determined that, for the purposes of the invention, the height of the wedges is preferably a small fraction of the wedge width (longitudinally); preferably of the order of 1/6 or so.
Tests have shown the effectiveness of such a construction for supplementing night-time retroreflection with adequate daylight marker observation even under shadowing conditions, for the marker strip of Fig. 1 of the following speci-fication~l ` !''` ' .. . .
. . . . .`.
122ZlS~ l ', . I
Flat top surface (Z) w~dth 300 mils Valley floor (1') width 300 mils ~idge hei~ht (vertical height of 2', 2"~ 50 mils Angle c~ ~ubstantially 0_45D
Glass beads (3) 5-10 mils diameter (n=l.9) When observed from a light source directed at an angl~
of about 85 from the normal, the light return by retroreflection from surfaces 2' or 2" was ex-cellent. As placed on a pavement surface R and observed late in the afternoon on a cloudless sunny day, with the marker strip 1 oriented so that heavy shadows of the ridges 2', 2" were formed on the valley floors 1' between the same, viewing at angles of 45 to 85 from the normal in the general direction of the sun, demonstrated that the marker appeared clearly light in tone against the dark road surface. In night time retroreflection, it has been determined that a motorist at 1200 feet distance should be able to view the top row of 10 mils beads on the wedge ridges.
- . .
. , `" .
. . ' ~ ' lZZZ157 .
In Flg. 2, the provlsion Or retrorer1ect1On beads 3 is shown over all surfaces of the marker strip 1. . I
A satisfactory technique for fabricating the specially configured marker strips of the 1, invention involves the use of a mold machined out of, for example, an aluminum block, say 4 j inches wide and 1/2 inch thick. The grooves for ~
the samples above described were 300 mils wide j at the tops (corresponding to marker top surfaces 2) with 30 sloping sides (corresponding to 2', 2n), ;¦
50 mils deep. Each groove was spaced 600 mils apart. Narrow strips of 5 mil-thick polyethelene ¦;
were secured to the ~loping walls of the mold grooves with a suitable heat-resistent adhesive 4.
The told was heated to about 280F and glass mlcro-~ .
'. ' .....
i' : , . `' ` ' ~ .
'`......... ` _ ' .. 122;~1S7 ':
spheres 3 (10 mils diameter, with a refractive index n of about 1.9) were poured into the grooves and pressed into the softened polyethelene. Af~er cooling the mold, the e~cess microspheres were removed so that the only ones remaining were those immersed to approximately 4~/. of their diameters in the polyethelene. Next, a plastisol of PVC
containing a white pig~ent was added to fill the grooves of the mold and cover the top side to a depth of about 15 mils. This was placed in a heated oven for sufficient time to ensure bringing the plastisol to a temperature of about 330F in order to fuse and solidify the castin~. hThen cooled, the PVC casting was stripped from the mo~d with the microspheres now securely anchored to about 60% of their diameters in the sloping sides of the ridge or wed~e walls of the PVC cast- ' in~. ¦
Further modifications will sug~est them-selves in the light of the above to those skilled in this art, and such are considered to fall within the spirit and scope of the invention as defined in the appended claims.
!
J :
'` . - I'
A more suitable approach for obviating these problems has resided in the use of thin flex.ble shee-ine on which ls contalned a ser1es ..
_. . . . . . .
`.
~`-;' ', , , .
l~ZZ15q ' - . ^' of very low profile raised pavement markers as described, for example, in my earlier U. S.
Letters Patent ~os. 3,920,346: 4,040,760s and 4,069,787~ and in Patent Nos. 4,145,112~
4,182,548; and 4,236,788. With the exception of the constructions of my said Patent Nos. .
4,040,760 and 4,069,787, such sheet markers are dependent upon having the main body of the marker constructed so as to be transparent to light, rendering the devices subject to serious light ¦ -loss effects in use, caused by abrasion and ¦ -accumulated dirt. In my said earlier construc- j tions, embodying the use of somewhat saw-tooth successive wed~es carried by a thin road-attachable strip, while quite satisfactory operation can be attained, it has been found that shadow effects when heading into the sun, and modification of results after the wedges have experienced some wear, as from extended use and/or snowplow de-facement or the like, do not permit as effective marking in daylight, dusk or under other adverse conditions as may be desirable.
;
122Z157 ' .
-7- ` `
In the case of the successive wedges -of substantially trian~ular shape taught in my said Patent No. 4,040,760, for example, extended use revealed that under certain conditions of ambient daylight, the pavement marker became somewhat difficult for the motorist to observe.
In particular, if the ~arker strip is oriented in such a way that the motorist is heading in the general direction of the sun on a cloudless !
day, the contrast between the marker and the road surface is so low that the marker becomes diffi- ¦
cult to distinguish. During these conditions, ¦
the sun will cast a shadow of each wedge on the valley floor between the wedges. Those faces of the wedges observed bythe motorist~ furthermore, are all contained within the shadow and thus appear ¦
black, introducing great difficulty in distinguish-ing the marker from the dark road surface. Ihe appearance of blackness or the poor contrast !
between the marker and the road surface is at a peak when the sun is at a low angle on a cloudless day.
:; - !
I
, , . , .
- ' ' ` ` . i .
. ~
. . '. ` ` ` ` ` ., . .` "~`~
. .
~2~Z157 .
;. ~ It was fortuitously discovered that - by changing the saw^tooth shape from triangular to trapezoidal, but onl.y with appropriate wedge length tO successive wedge spacing, this problem was completely obviated, and simultaneous other marked advantages in greater wear-resistance and life under abrasion, including snowplowing, also followed. The flat tops of the now trapezoidal-shaped wedge, if of appropriate dimensions and spacing, reflect sunlight and reduce the wedge shadow effect admirably well.
An object of the present invention, accord-ingly, is to provide a new and improved marker structure that shall not be subject to the above and other disadvantages, but that can obviate shadow and discontinuous effects and provides a marked improvement in wear and use under adverse - environmental conditions.
An additional object of the invention is to provide a flexible sheet material pavement marker or the like which will be clearly visible ~' , ' ,9 . .
as à continuous line by ambient dayli~ht as well -as retroreflection from automobile headlamps at night, even during a heavy downpour of rain.
A further object is to provide a flex-ible sheet material pavement marker with a con-figuration and low profile sufficient to resist uprooting by normal snowplow action.
Still another object is to provide a highly visible highway marker for night driving with a long life and with good retroreflection characteristics maintained throughout such life.
A further ob~ect is to provide a novel marker of more general utility, as well.
Other and further objects are explained hereinafter and are more particularly pointed out in the appended claims.
In summary, however, the invention, from one of its aspects, contemplates in combination with a roadway surface and the like, a direction-indicating surface marker strip of-~+-S~R~
flexible plastic material adherable to said surtace `
`f:
.' , ' " '" ` ' ', ', 122i~157 by a thin layer of adhesive between the strip and the surface, the strip being intermittently deformed upward to provide successive transversely disposed wedges of sub-stantially trapezoidal shape in longitudinal section, each wedge having a substantially flat top surface bounded by upwardly and downwardly acute-angle inclining front and rear surfaces, the inclining surfaces being provided with embedded retroreflecting beads. Preferred details of construction and best mode embodiments are later set forth.
The invention will now be described with reference to the accompanyin~ drawings, Fig. 1 of which is a lonaitudinal sectional view of a preferred embodiment of the invention; and Fig. 2 is a similar view of a modification.
lZZZ157 `11~
Referring to Fi~. 1, the thin flexible plastic elongated road marker strip 1 is shown adhered by a bottom adhesive layer 4 to the road-way or other surface K. Suitable materials are described in my said earlier patents and are hereinafter discussed. As previously described, the somewhat saw-tooth wed~e construction i8 illustrated in the form of substantially trape-zoidal (in longitudinal section) wedge pro~ections T having a flat top surface 2 and bounded by up-wardly and downwardly inclining front and rear ridge sùrfaces 2' and 2", all extending trans-versely across the strip 1, and all preferably integrally formed from the thin plastic material of the strip 1, with the wedges intermittently deformed upward of the strip.
A preferred range of acute angles cC
of inclination (or downward slope) enable proper operation in ~se as hereinafter discussed. At least the upwardly and downwardly inclined sur-faces 2' and 2" carry a retroreflective bead ~
layer( 9 ~ or the like 3. ~-: . ' . .
~ ' ' . .' .
.
~ - ~
~Z2Z157 -12- j! ~
, - .
ith this construction, it has been discovered that, instead of observing an apparent extension of a portion of one wedge face continu-ously merging with the next succeeding wedge face portion and so on, as described in my earlier ¦;
patents, in the case of the trapezoidal wed6e of ¦:
Fig. 1, there is an interruption in the apparent .
merging wedge faces by the width of the flat top surface 2 of the trapezoidal wedge T. Considering daylight operation, including heading into the . .
sun, when this diffusely reflecting flat top sur- :
face 2 has the same apparent area as that observable .
portion of the wedge face which is in shadow, it has been found that the visual effect of the sun shadow becomes sufficien~ly reduced to permit the marker 1 to be readily visually distinguished from :
the road surface ~. This provides ~arker indica- ;
tion under such daylight or dusk considerations that previous constructions do not adequately ';
provide. Increasing the area would provide even better dayli~ht contra-t between the marker and ~' , '- ' ' ' ,' ,~. j:
' ~
lZZZ157 the road surface. but the apparent brightness of night time retroreflection from automobile headlamps would diminish. The condition for pro-ducing apparent equal areas is fulfilled when the width of the flat top surface 2 of the trape-zoidal wedge T is made about equal (comparable) to that of the valley floor 1' between successive wedges. It has also been determined that, for the purposes of the invention, the height of the wedges is preferably a small fraction of the wedge width (longitudinally); preferably of the order of 1/6 or so.
Tests have shown the effectiveness of such a construction for supplementing night-time retroreflection with adequate daylight marker observation even under shadowing conditions, for the marker strip of Fig. 1 of the following speci-fication~l ` !''` ' .. . .
. . . . .`.
122ZlS~ l ', . I
Flat top surface (Z) w~dth 300 mils Valley floor (1') width 300 mils ~idge hei~ht (vertical height of 2', 2"~ 50 mils Angle c~ ~ubstantially 0_45D
Glass beads (3) 5-10 mils diameter (n=l.9) When observed from a light source directed at an angl~
of about 85 from the normal, the light return by retroreflection from surfaces 2' or 2" was ex-cellent. As placed on a pavement surface R and observed late in the afternoon on a cloudless sunny day, with the marker strip 1 oriented so that heavy shadows of the ridges 2', 2" were formed on the valley floors 1' between the same, viewing at angles of 45 to 85 from the normal in the general direction of the sun, demonstrated that the marker appeared clearly light in tone against the dark road surface. In night time retroreflection, it has been determined that a motorist at 1200 feet distance should be able to view the top row of 10 mils beads on the wedge ridges.
- . .
. , `" .
. . ' ~ ' lZZZ157 .
In Flg. 2, the provlsion Or retrorer1ect1On beads 3 is shown over all surfaces of the marker strip 1. . I
A satisfactory technique for fabricating the specially configured marker strips of the 1, invention involves the use of a mold machined out of, for example, an aluminum block, say 4 j inches wide and 1/2 inch thick. The grooves for ~
the samples above described were 300 mils wide j at the tops (corresponding to marker top surfaces 2) with 30 sloping sides (corresponding to 2', 2n), ;¦
50 mils deep. Each groove was spaced 600 mils apart. Narrow strips of 5 mil-thick polyethelene ¦;
were secured to the ~loping walls of the mold grooves with a suitable heat-resistent adhesive 4.
The told was heated to about 280F and glass mlcro-~ .
'. ' .....
i' : , . `' ` ' ~ .
'`......... ` _ ' .. 122;~1S7 ':
spheres 3 (10 mils diameter, with a refractive index n of about 1.9) were poured into the grooves and pressed into the softened polyethelene. Af~er cooling the mold, the e~cess microspheres were removed so that the only ones remaining were those immersed to approximately 4~/. of their diameters in the polyethelene. Next, a plastisol of PVC
containing a white pig~ent was added to fill the grooves of the mold and cover the top side to a depth of about 15 mils. This was placed in a heated oven for sufficient time to ensure bringing the plastisol to a temperature of about 330F in order to fuse and solidify the castin~. hThen cooled, the PVC casting was stripped from the mo~d with the microspheres now securely anchored to about 60% of their diameters in the sloping sides of the ridge or wed~e walls of the PVC cast- ' in~. ¦
Further modifications will sug~est them-selves in the light of the above to those skilled in this art, and such are considered to fall within the spirit and scope of the invention as defined in the appended claims.
!
J :
'` . - I'
Claims (19)
- What is claimed is:
l. In combination with a roadway surface and the like, a direction-indicating surface marker strip of pre-formed flexible plastic material adherable to said surface by a thin layer of adhesive between the strip and said surface, said strip being intermittently deformed upward to provide successive trans-versely disposed wedges of substantially trapezoidal shape in longitudinal section, each wedge having a substantially flat top surface bounded by upwardly and downwardly acute-angle inclining front and rear surfaces, said inclining surfaces being provided with embedded retroreflecting beads, and the flat top surface width being comparable to the width of the valley surfaces in the strip between successive wedges. - 2. A direction-indicating strip as claimed in claim l and in which said acute angle is within substantially the range of 0°-45°.
- 3. A direction-indicating strip as claimed in claim 1 and in which the height of said wedges is a fraction of said flat top sur-face width.
- 4. A direction-indicating strip as claimed in claim 3 and in which said width is of the order of a few hundred mils and said frac-tion is of the order of one-sixth.
- 5. A direction-indicating strip as claimed in claim 1 and in which all of said flat top, front, rear and valley surfaces are provided with said retroreflecting beads embedded therein.
- 6. A direction-indicating strip as claimed in claim 1 and in which said beads are about 60% embedded in the strip material.
- 7. In combination with a roadway surface and the like, a direction-indicating surface marker strip of flexible plastic material adherable to said surface by a thin layer of adhesive between the strip and said surface, said strip being intermittently deformed upward to provide successive transversely disposed wedges of substantially trapezoidal shape in longitudinal section, each wedge having a substantially flat top surface bounded by upwardly and downwardly acute-angle inclining front and rear surfaces, said inclining surfaces being provided with embedded retroreflecting beads.
- 8. A direction indicating strip as claimed in claim 7 and in which said beads protrude from said inclining surfaces.
- 9. A direction indicating strip as claimed in claim 8 and in which no beads protrude from the valley surfaces in the strip between successive wedges.
- 10. A direction indicating strip as claimed in claim 7 and in which said flat top surfaces are also provided with embedded retroreflecting beads.
- 11. In combination with a roadway surface and the like, a direction-indicating surface marker strip comprising plastic material secured to said surface, said strip being intermittently deformed upward to provide successive wedges of substantially trapezoidal shape in longitudinal vertical section, each wedge having a top surface bounded by inclined front and rear surfaces, the height of each wedge being small relative to the longitudinal dimension of the top surface of the wedge, each of said inclined surfaces being provided with a surface layer of retroreflecting beads, said layer of retroreflecting beads having at least a top row thereof which is visible at night to a motorist hundreds of feet away by retroreflection of vehicle headlights, the configuration, dimensions, and spacing of the wedges being selected to reduce substantially the obscuring of the marker strip by shadows of the wedges in sunlight, so that the marker strip is clearly visible to a motorist during the day as well as at night, and whereby the marker strip has a long effective life even when subjected to abrasion and dirt.
- 12. A direction-indicating surface marker strip in accordance with Claim 11, wherein the top surface of each wedge has a substantially horizontal area that is substantially greater than the area of each inclined surface.
- 13. A direction-indicating surface marker strip in accordance with Claim 11, wherein successive wedges of said strip are separated by a substantially horizontal surface having an area that is substantially greater than that of each inclined surface.
- 14. A direction-indicating surface marker strip in accordance with Claim 11, wherein each inclined surface forms an angle with respect to vertical that is substantially within the range of 0 degrees to 45 degrees.
- 15. A direction-indicating surface marker strip in accordance with Claim 11, wherein the height of each wedge is a small fraction of the longitudinal dimension of the top surface of the wedge.
- 16. A direction-indicating surface marker strip in accordance with Claim 15, wherein the longitudinal dimension of said top surface is of the order of a few hundred mils and said fraction is of the order of 1/6.
- 17. A direction-indicating surface marker strip in accordance with Claim 11, wherein all of the top and inclined surfaces of said wedges are provided with retroreflecting beads, as well as surfaces of said strip between successive wedges.
- 18. A direction-indicating surface marker strip in accordance with Claim 11, wherein said beads are about 60 percent embedded in the strip material.
19. For use with a roadway surface and the like, a direction-indicating surface marker strip comprising plastic material adapted to be secured to said roadway surface, said strip being intermittently deformed upward to provide successive wedges of substantially trapezoidal shape in longitudinal vertical section, each wedge having a top surface bounded by inclined front and rear surfaces, each top surface having a substantially horizontal surface area that is substantially greater than the area of each inclined surface, successive wedges of said strip being separated by substantially horizontal surfaces each having an area substantially greater than that of each inclined surface, each inclined surface forming an angle with respect to vertical that is substantially within the range of 0 degree to 45 degrees, the height of each wedge being a small fraction of the longitudinal dimension of the top surface of the wedge, each of said inclined surfaces being provided with a surface layer of retroreflecting beads, said layer of retroreflective beads having at least a top row thereof which is visible at night to a motorist hundreds of feet away by retroreflection of vehicle headlights, the configuration, dimensions, and spacing of - Claim 19 cont'd...
the wedges being selected to reduce substantially the obscuring of the marker strip by shadows of the wedges in sunlight, so that the marker strip is clearly visible to a motorist during the day as well as at night, and whereby the marker strip has a long effective life even when subjected to abrasion and dirt.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US35103782A | 1982-02-22 | 1982-02-22 | |
| US351,037 | 1982-02-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1222157A true CA1222157A (en) | 1987-05-26 |
Family
ID=23379323
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000420753A Expired CA1222157A (en) | 1982-02-22 | 1983-02-02 | Sheet material marker surface for roadways and the like |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS58156611A (en) |
| AU (1) | AU561819B2 (en) |
| CA (1) | CA1222157A (en) |
| FR (1) | FR2522034B1 (en) |
| GB (1) | GB2115862B (en) |
| HK (1) | HK37888A (en) |
| IT (1) | IT1169106B (en) |
| SE (1) | SE508321C2 (en) |
| SG (1) | SG98787G (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0745723B2 (en) * | 1984-10-22 | 1995-05-17 | アトム化学塗料株式会社 | High-brightness road marking sheet material |
| GB2183276B (en) * | 1985-10-04 | 1988-09-21 | Aph Road Safety Ltd | Traffic bollards |
| CA1307971C (en) * | 1988-06-09 | 1992-09-29 | Thomas Peter Hedblom | Patterned pavement marking |
| US4969713A (en) * | 1988-12-12 | 1990-11-13 | Brite Line Corporation | Marker strip surface for roadways and the like |
| JP2002161518A (en) * | 2000-11-22 | 2002-06-04 | Natl Inst For Land & Infrastructure Management Mlit | Boundary line for passage of vehicle |
| JP2008215002A (en) * | 2007-03-06 | 2008-09-18 | Sekisui Jushi Co Ltd | High visibility road marking line and method of forming high visibility road marking line |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU35481A1 (en) * | ||||
| US2579467A (en) * | 1947-06-14 | 1951-12-25 | Alan E Brickman | Pavement lane marker |
| FR1438888A (en) * | 1965-07-03 | 1966-05-13 | Process for manufacturing a reflective coating for road marking, device for its implementation and coating thus obtained | |
| GB1107799A (en) * | 1965-07-19 | 1968-03-27 | Tarkett Ab | Improvements in or relating to light reflecting road marking materials, and methods for their manufacture |
| CH486600A (en) * | 1967-09-05 | 1970-02-28 | Eigenmann Ludwig | Road surface signaling material |
| FR1604009A (en) * | 1968-08-05 | 1971-06-28 | Reflective element, eg a road marker - stud | |
| IT1022451B (en) * | 1974-09-30 | 1978-03-20 | Eigenmann Ludwig | PREFABRICATED STRIP FOR HORIZONTAL ROAD SIGNAL AND METHOD FOR ITS PREFABRICATION |
| FR2375394A1 (en) * | 1976-12-24 | 1978-07-21 | Ligne Blanche | Reflective strip for road markings - has glass balls embedded in plastic coating with impressed grooves inclined to direction of road |
| US4145112A (en) * | 1977-07-14 | 1979-03-20 | Minnesota Mining And Manufacturing Company | Low-profile raised retroreflective sheeting |
| JPS5469227A (en) * | 1977-11-10 | 1979-06-04 | Eigenmann Ludwig | Tape material for road marking |
| JPS55142301A (en) * | 1979-04-23 | 1980-11-06 | Ferro Corp | Rear reflective marking tape |
-
1983
- 1983-02-02 GB GB08302814A patent/GB2115862B/en not_active Expired
- 1983-02-02 CA CA000420753A patent/CA1222157A/en not_active Expired
- 1983-02-09 AU AU11266/83A patent/AU561819B2/en not_active Expired
- 1983-02-11 SE SE8300731A patent/SE508321C2/en not_active IP Right Cessation
- 1983-02-17 JP JP58025468A patent/JPS58156611A/en active Granted
- 1983-02-21 FR FR838302744A patent/FR2522034B1/en not_active Expired
- 1983-02-22 IT IT19693/83A patent/IT1169106B/en active
-
1987
- 1987-11-05 SG SG987/87A patent/SG98787G/en unknown
-
1988
- 1988-05-19 HK HK378/88A patent/HK37888A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| SE508321C2 (en) | 1998-09-28 |
| IT8319693A0 (en) | 1983-02-22 |
| FR2522034B1 (en) | 1989-04-21 |
| GB8302814D0 (en) | 1983-03-09 |
| JPS58156611A (en) | 1983-09-17 |
| GB2115862A (en) | 1983-09-14 |
| SG98787G (en) | 1988-09-23 |
| AU561819B2 (en) | 1987-05-21 |
| JPH0157207B2 (en) | 1989-12-05 |
| IT1169106B (en) | 1987-05-27 |
| SE8300731D0 (en) | 1983-02-11 |
| GB2115862B (en) | 1986-06-18 |
| AU1126683A (en) | 1983-09-01 |
| HK37888A (en) | 1988-05-27 |
| SE8300731L (en) | 1983-08-23 |
| FR2522034A1 (en) | 1983-08-26 |
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Legal Events
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| MKEX | Expiry | ||
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Effective date: 20040526 |