Note: Descriptions are shown in the official language in which they were submitted.
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This application is a division of my Canadian Patent Application
Serial No. 306,761 filed July 4, 1978.
This invention relates to roadway markers or guide posts. More part-
icularly, it is concerned with resilient posts which permit nondestructive de-
formation upon impact by a moving object.
Vehicle traffic control requires the use of road signs and markers as
aids in solving the various problems associated with traffic safety and direc-
tion. It has been found that a useful characteristic for such signs and markers
is that these posts have the ability to withstand vehicle impact, without re-
quiring subsequent replacement. An attempt has been made to fill this need withvarious configurations of posts. However, the structural design of such posts
has involved the consideration of two opposing structural features, i.e. the
elasticity required during dynamic conditions to permit the post to nondestruct-
ively bend with vehicle impact and the longitudinal rigidity required during
static conditions to withstand forces resulting as the post is driven into a
hard surface.
The elasticity is necessary in view of frequent high speeds associated
with impacts between a moving vehicle and stationary post. In such cases, if
the post could not bend it would likely shear off, and would have to be replaced.
Mere bendability, however, is not sufficient, since each time a post was bent it
would have to be straightened before it could again be functional. This could
involve high maintenance costs. Ideally, a post should also have sufficient
elasticity that it will automatically assume its proper upright configuration
after dissipation of any impact forces.
While elasticity is desirable, the elasticity may present a practical
problem when installation of the post is considered. In the past, when deform-
able plastics have been used as post material, installation has frequently re-
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ll;~}Z~6
quired predrilling a hole or insertion of some support receptable into the
ground, with the subsequent positioning of the plastic post into the hole or
receptacle. These preliminary steps were required because such previously known
elastic posts would not withstand a buckling force applied during attempts to
drive the posts into hard surfaces. Consequently, the same elastic properties
which permitted the nondestructive deformation upon impact caused the buckling
of a post subjected to a driving force along its axis.
Attempts have been made to incorporate the dual requirements of
elasticity and rigidity by utilizing a spring within an otherwise rigid post,
and with the rigid parts of the post being secured onopposite ends of the
spring. Installation was by compressing the spring and then pounding along the
now rigid longitudinal axis. After installation, the deformable character of
the post was accomplished by the transverse elastic property of the included
spring.
This configuration, however, has several apparent disadvantages. The
rigid portion of the structure has customarily been made of strong materials
which may dent or otherwise damage the impacting vehicle. Furthermore, the use
of such rigid materials and springs and the assembly requirements result in
excessive costs for the posts.
United States Patent No. 3,875,720 discloses a second approach to the
problem, of providing elasticity in a post that can be driven. In this patent a
post is formed by a bundle of flexible rods that are clamped together to obtain
the desired rigid property required during the static installation stage of the
post. Deformation of the post during dynamic conditions is permitted by deflec-
tion of the various flexible rods away from the central axis of the post struc-
ture. Here again, however, economic factors appear to have impeded utilization
of such structure despite the growing need for such a post.
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It is therefore an object of the present invention to provide a de-
formable post configuration having both longitudinal rigidity and bending
elasticity to facilitate driving emplacement and subsequent impact without de-
structive deformation.
It is a further object of the present invention to obtain this dual
character by utilization of a geometrical configuration adapted to minimize
bending stress while at the same time retaining the high modulus of elasticity
necessary to preserve longitudinal rigidity.
An additional object of the present invention is to accomplish the
afore-mentioned dual character by means of reinforcing a web structure with a
suitable arrangement of fibers.
A still further object of this invention is to develop the desired
dual character of elasticity and rigidity by incorporating reinforcing rib
structure longitudinally along the post structure.
It is yet another object of the present invention to provide a post
structure having transverse flexibility to permit lateral contortion and/or de-
formation to a minimal thickness and thereby reduce moment of inertia and bend-
ing stress.
It is also an object of this invention to provide means for protecting
attached marker materials from impact and weather degradation.
These and other objects of the present invention are realized in a
post configuration (hereinafter referred to as a delineator) wherein the
delineator comprises an elongated web and associated reinforcing structure. The
web portion of the delineator provides the flexible properties which permit
bending of the delineator in response to a bending impact force. The reinforc-
ing structure is necessary to develop a high modulus of elasticity along the
longitudinal axis of the delineator. Such reinforcing structure is implemented
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by specific utilization of f:iber orientation within the web structure or by con-
figuring the structure geometrically to provide ribs having the desired high
modulus of elasticity which will complement the bending properties of the web
structure.
Thus, in accordance with a broad aspect of the invention, there is
provided a delineator including: a web structure having a tapered base to
facilitate insertion thereof into a hard surface and being constructed of a
material composition which develops a modulus of elasticity (E) sufficiently
high, when taken in combination with the moment of inertia (I) of said web
structure, to withstand a longitudinal impact force having values up to a maxi-
mum buckling load (PE) in accordance with a delineator length parameter (L) as
defined by the relation PE = 4~2 El, said impact force being applied near the
- top of a longitudinal axis of said delineator during static installation condi-
tions at said hard surface; said product of EI being variable in response to de-
formation of said delineator by a lateral impact force which modifies said geo-
metric structure to decrease the moment of inertia (I) and develop a delineator
bending radius (R) as defined by the relationship R = EI, wherein M is the bend-
M
ing moment of said delineator, said bending radius being sufficiently low to
permit passage of a vehicle over said delineator, said material composition
having sufficient elasticity to restore to its upright orientation upon dissipa-
tion of said impact force; said geometric structure comprising a nonplanar
impacting surface of said web structure which responds with angular contortion
upon occurrence of said lateral impact, thereby decreasing the moment of inertia
: of said delineator during bending motion, reducing said EI product from a long-
itudinal rigid structure to a flexible structure during deformation.
Other objects and features will be obvious to a person of ordinary
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skill in the art from the following detailed description, taken with the
accompanying drawings, in which
Figure 1 is a fragmentary perspective view of a delineator of the pre-
sent invention, having a partially cut away section.
Figure 2 is a perspective view of the delineator in combination with a
roadway.
Figure 3 is a fragmentary, partially cut away view of a second embodi-
ment of the present invention.
Figure 3a shows an enlarged, fragmentary view taken within the line
3a-3a of Figure 3.
Figure 4 depicts a fragmentary perspective view of an additional
embodiment of the present invention.
Figure 4a shows an enlarged, fragmentary view taken within the line
4a-4a of Figure 4.
Figure 5 is a perspective view of a delineator immediately after
impact with a moving object.
Figure 6a is a horizontal cross-section view, taken on the line 6a of
Figure 5.
Figure 6b is a horizontal cross-section view, taken along the line 6b
of Figure 5.
Figure 7 shows a fragmentary view of an additional embodiment of the
present invention.
Figure 8 shows a fragmentary view of a delineator enclosed by a rigid-
body casing, shown in perspective.
Figure 9 depicts a protective cap for use with the subject delineator.
Referring now to the drawings:
The present invention relates to the establishment of proper elastic
32Q~36
and rigid mechanical properties within a delineator structure. The normal use
of such a roadway delineator entails two separate forms of stress application.
Initially, the delineator is subjected to installation stress as the delineator
is driven into a hard surface, such as ground. Typically, this driving force is
applied to the top end of the delineator and therefore represents a longitudinal
force extending down the length of the delineator. It is noted that this stress
arises when the delineator is in a static state, i.e. when no bending forces are
being applied. The required mechanical properties necessary to avoid buckling
of the delineator under the applied driving load, are represented in the follow-
ing formula:
E ~ EI
L2
- Where: E=elastic modulus in compression
I=moment of inertia
L=length of the column
PE=maximum buckling load
Once the length L of the delineator is established the product of EI
becomes determinative of the ultimate buckling load the post can withstand.
A second form of stress anticipated for the delineator is *he bending
stress applied upon impact by a moving object with a surface of the delineator.
This form of stress, arising during dynamic conditions, is represented by the
following relationship:
fb = MC
I
Where: fb=bending stress
M=bending moment
C=distance from neutral axis to point of stress
Bending moment M is defined by the expression:
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(3)
M = EI
Where: E=elastic modulus
I=moment of inertia
R=radius of curvature
In dealing with both forms of stress, therefore, it is imperative that
the proper relationship be established between the elastic modulus E and the
moment of inertia I.
From the equations defining the respective forms of stress applied to
the delineator, it is apparent that rigid posts, such as those made of metal or
wood, have a very high buckling load factor, PE. With such materials both E and
I may have very large values. This factor is favorable during installation, but
may be catastrophic upon vehicle impact.
This adverse condition is apparent from equation (3), which may be re-
written in the form R = EI. In this case it is apparent that the large product
M
of EI from the previous buckling formula (1) would result in a large radius of
curvature R which is clearly adverse to applications for delineators to be sub-
ject to impact deformation. Customarily, such impact will usually involve a
motor vehicle whose structure will require the delineator to deform to a radius
of a curvature of approximately 18 inches (45.72 cm). Where the product of EI
is high and the point of impact is approximately 18 inches (45.72 cm) above
ground level (making M quite low in value) the resultant radius of curvature is
far too large and the motor vehicle may simply shear off the delineator between
the point of impact and ground level.
An important aspect of the present invention is the recognition that,
under typical uses of a delineator, the value of EI in the static condition dur-
ing installation will not satisfy the bending requirements experienced during
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impact at a lateral surface. Inherent properties within the delineator are re-
quired which will develop a lower EI product during dynamic bending. Simply
stated, the most versatile delineator must respond to a driving load with a high
EI product to preclude buckling, but must experience a lower EI during bending
subsequent to impact.
The present invention involves unique strùctural design to establish a
proper balance between E, the elastic modulus and I, the moment of inertia.
Whereas large values of E are required to maintain the necessary rigidity to
withstand the longitudinal driving force arising during static conditions of
installation, I is of minimal value to improve the bending ability of the delin-
eator to achieve a low radius of curvature. The delineator of the present in-
vention provides a variable EI response to the respective loading and bending
stresses, to satisfy both static and dynamic conditions in a single embodiment.
Figure 1 illustrates one embodiment of the delineator utilizing con-
cepts of the subject inventionl wherein the appropriate balance between E and I
is obtained by a combination of geometrical structure and material composition.
The delineator, shown generally as 10, is constructed of a plastic binder with
reinforcing fibers. The plastic binder may be any suitable plastic which is
capable of withstanding the variations of temperature to which it will be sub-
jected and which possesses the desired elongation characteristics to preventmassive fracturing upon impact.
Thermosetting resin material is particularly well suited for this
application in as much as it is not dependent upon temperature to maintain its
flexibility. To the contrary, many thermoplastic materials become too brittle
when exposed to subfreezing temperatures and result in massive fractures upon
impact with a moving vehicle. Where the thermoplastic resin is capable of with-
standing temperature variation without concurrent hardening, however, such mate-
llV~Q~6
rial may well be suited as binder material for the subject invention.
In order to establish the necessary rigidity to the delineator body10, reinforcing fiber is embedded within the binder material. A portion 17 of
this fiber is positioned longitudinally along the length of the delineator
structure. For extra longitudinal strength, a high modulus fiber such as
"KEVLAR" may be used. A second layer 16 of fiber material is oriented in random
direction to establish tensile strength and to contribute to the proper balance
between rigidity and flexibility. A surface coating 15 is utili~ed to protect
the contained binder/fiber combination from weather, ultraviolet rays and other
adverse effects of the environment. In addition to the suggested form of Figure
1, the arrangement of longitudinal versus random fibers within the structure may
be varied such that the random fiber may form a core, with the longitudinal
fiber comprising the second layer thereon.
It has been determined that at least seven percent by weight but no
more than sixty percent of the fiber arrangement be in random orientation. The
remaining amount of fiber is longitudinally oriented to establish the rigidity
required for driving the delineator into the ground. Furthermore, although
random fiber orientation is described and is shown in Figure 1, similar trans-
verse flexibility and tensile strength properties can be established where fiber
orientation is directed at various predetermined transverse angles of orienta-
tion, such as is best shown at 36 in Figure 3.
It has also been found that where the binder material comprises
twenty to forty percent by weight of the delineator structure, use of more than
sixty percent random fiber adversely affects the elastic character which is re-
quired to restore the delineator to its original position after impact. Also,
failure to use at least forty percent of the fiber in the longitudinal orienta-
tion, without other reinforcing structure, will result in insufficient resil-
.
-.
Q86
ience or elastic modulus to permit the delineator to be driven into the ground.
This use of proper amounts of fiber coordinated between transverse and longitu-
dinal orientations, represents an effective method of establishing the appropri-
ate E and I within the delineator structure.
A second method for establishing sufficient elastic modulus while pre-
serving resistance to a buckling load is accomplished through geometrical con-
figurations such as shown for examples by the rib structures 11 and 13 in Figure
1. In utilizing reinforcing ribs to obtain the higher elastic modulus desired,
it is important that such rib structure not extend a substantial distance away
from delineator surfaces 14 and 18, since bending stresses arising therein dur-
ing curvature of the delineator will result in longitudinal shearing along the
junction of the rib and web portion 12 of the delineator body. The effect of
slightly protruding rib structure, however, is to extend the apparent thickness
of the delineator and thereby increase the moment of inertia 1, without subject-
ing the rib structure to excessive stress during the dynamic bending phase. By
reinforcing such rib structures 11 and 13 with longitudinal fiber, 17, the
elastic modulus E is also increased resulting in even greater rigidity, without
increasing rib thickness.
In circumstances where less buckling stress is anticipated with re-
spect to installation of delineator, rib structure may be omitted and both E andI can be satisfied by the use of proper orientations of reinforcing fibers in
combination with a nonplanar ~i.e. concave) web structure such as is illustrated
by the delineator structure 70 in Figure 7. Such a slightly concave delineator
body, reinforced with longitudinal fibers, can withstand a limited driving load
imposed at the top thereof while retaining sufficient flexibility to bend with-
out destructive deformation.
A second configuration is illustrated in Figure 3 and 3a, in which a
- 1 0 -
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single rib 31 supplies the reinforcing strength to permit driving of the deline-
ator into the hard surface. In this case, the reinforcing rib 31 is located on
a nonimpacting surface 34 of the delineator 30. The thickness of the web por-
tiOIl 32 will depend upon the anticipated impact force associated with the delin-
eator environment. As with previous examples, the full web with reinforcing rib
structure may be fully reinforced with the appropriate combination of transverse
and longitudinal fibers 36 and 37.
With the single reinforcing rib 31, a somewhat larger rib thickness
might be desired to increase moment of inertia and longitudinal rigidity. Al-
though this larger rib size will improve drivability, excessive size will reducethe desired flexibility required for withstanding bending stress. This reduc-
tion in flexibility may be partially alleviated by reducing longitudinal fiber
content in the rib body and slightly increasing the transverse fiber arrangement
to develop a minor fracture capability upon the initial impact of a bending
force with the delineator. With this characteristic construction the delineator,
prior to bending impact, has increased longitudinal rigidity to withstand the
anticipated driving force to be applied during installation. After installation,
however, a reduction of moment of inertia and improved flexibility to withstand
bending stress is achieved upon an initial impact which develops transverse
fractures 33 along the rib length.
When such impact occurs at the front surface 38, the delineator struc-
ture curves rearward, causing compression on the back surface 34 and reinforcing
rib 31. Because of the shorter radius of curvature imposed upon rib 31, in-
creased compression occurs longitudinally along the rib structure and with the
reduced longitudinal fiber, minor transverse fracturing occurs 33. Total shear-
ing or destruction of rib 31 is avoided by means of sufficient longitudinal and
random fiber content within the rib portion, with random fiber arrangements be-
~1~20~6
ing interconnected and intermingling with the attached web structure. The endresult, therefore, is a rib reinforcement having small, multiple transverse
cracks along its length to facilitate subsequent compliance to bending stress.
At the same time, however, some stabilizing influence remains by reason of some
surviving continuity of the rib structure.
An additional method of developing high EI for drivability, but lower
EI during bending movements is to incorporate a network of microspherical voids
within the delineator structure. This concept is illustrated in Figure 4a.
Such voids 45 can be introduced during fabrication by conventional techniques
and will operate to lower the movement of inertia and thereby enhance flexi-
bility. Furthermore, although longitudinal rigidity will be retained due to
static strength inherent in this configuration, a violent lateral impact will
cause the microspheres to partially collapse and operate as tiny hinges to
facilitate bending movement.
As shown best in Figure 4, other geometrical configurations can be
used to establish a balance between E and I. The particular configuration shown
in Figure 4 utilizes structural thickness to develop the increased elastic
modulus required to obtain drivability for the delineator 40. By utilizing rib
structures 43 at the edges of the web structure 42 and a thicker central portion
of web structure 41, an increased effective thickness is obtained to satisfy
ultimate buckling load requirements. Such effective thickness extends from the
front contacting edges of the forward extending ribs 43 through the rearward
ridge of the central reinforcing rib 41.
This effective thickness, of course, represents the static condition
of the structure of the delineator. On impact, bending forces cause the contor-
tion of the outer ridges 43 in angular rearward movement. This structural
deformation facilitates improved bending because of the concurrent reduction of
11~ 6
apparent thickness of the delineator body and moment of inertia. Such structure
directly implements the concept of variable EI product in response to static and
dynamic conditions. In Figure 5, the deformed delineator 50 is shown immedi-
ately after impact with an automobile 58. The elastic forces of the delineator
are in the process of restoring the upper portion 59 of the delineator to its
original upright position. Figure 6b illustrates the unflexed, apparent thick-
ness of the delineator viewed at the cross section view taken along line 6b.
Here the hard ground structure forces the delineator to retain its static con-
figuration, having an apparent thickness extending from i to iv. It is this ex-
tended thickness dt which strengthens longitudinal rigidity in the otherwise
thinned web structure between ii and iii, and provides the higher EI for this
condition.
Such configuration is modified, however, during contortions illustr-
ated in Figure 5, as represented in the Figure 6a view. The thinner structure
of the web body 62 permits greater flexibility and causes rotation of the more
massive ridge members 63 in angular rotation rearward. The effect of such con-
tortion is to reduce the thickness of the delineator from its static thickness
of dt in Figure 6b to a reduced thickness di of Figure 6a. The relationship de-
fined by Equation (2)
fb MC
shows that any reduction in thickness causes a decrease in the value of C, the
distance from the neutral axis to the point of stress. This factor assists in
satisfying the requirement for reduced moment of inertia, or increased flexi-
bility, to avoid destructive deformation of the delineator. This characteristic
of lateral angular contortion is developed where reinforcing rib structure,
having less flexibility than the attached web structure in the transverse direc-
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tion, is subjected to such a bending impact force.
In addition to the application of this principle to planar type web
structures such as illustrated in Figures 1, 2, 3, 4, and 5, nonplanar web
structures are likewise adaptable to a proper balance of rigidity and elasticity.
Figure 7 illustrates one such embodiment, having lateral edges 72 that are com-
prised of thermosetting resins which may be reinforced with appropriate fibers
in the transverse and longitudinal directions and a central portion 73 contain-
ing a longitudinal section of thermoplastic material 74 having greater flexi-
bility than the attached thermosetting material section. As with the prior
example, impact at a frontal surface 78 causes rearward angular contortion at
the lateral edges 72 which effectively reduces the overall thickness of the
delineator, thereby improving its bendable character. The elastic properties of
both materials operate to restore the concave structure upon removal of the
impacting force. With the combination of concave structure for improved long-
itudinal rigidity and the improved transverse flexibility of the central section
73, this configuration is also satisfactory in so far as both elasticity and
rigidity are concerned.
A common feature of each embodiment described is that a unibody con-
struction exists which incorporates the intermingling of fibers or other
supporting rib structure with a web portion having a more flexible character.
During installation procedures the higher EI is realized in the reinforced sec-
tions of the delineator which operate as the primary load bearing element. Such
occurs, for example, at the central ridges, distal ribs, or any areas of greater
thickness. During bending contortions following impact, however, the angular
contortion of the more flexible web portion of the structure provides a reduced
moment of inertia and therefore a reduced stress due to the decreased distance
between the neutral axis and the various points of stress along the delineator
body.
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. .
Q~6
More specifically, the subject delineator includes a web structure
having a tapered base to facilitate insertion thereof into a hard surface and is
constructed of a material composition which develops a modulus of elasticity (E)
sufficiently high, when taken in combination with the moment of inertia (I) of
said web structure, to withstand a longitudinal impact force having values up to
a maximum buckling load (PE) in accordance with a delineator length parameter
(L) as defined by the relation PE = ~ EI said impact force being applied near
the top of a longitudinal axis of said delineator during static installation
conditions; said product of EI being variable in response to deformation of said
delineator by a lateral impact force which modifies said geometric structure to
decrease the moment of inertia (I) and develop a delineator bending radius (R)
as defined by the relationship R = EI, wherein M is the bending moment of said
delineator, said bending radius being sufficiently low to permit passage of a
vehicle over said delineator, said material composition having sufficient
elasticity to restore to its upright orientation upon dissipation of said impact
force; said geometric structure comprising a nonplanar impacting surface of said
web structure which responds with angular contortion upon occurrence of said
lateral impactJ thereby decreasing the moment of inertia of said delineator dur-
ing bending motion, reducing said EI product from a longitudinal rigid structureto a flexible structure during deformation.
With respect to delineators manufactured with a plastic binder and
reinforcing fibers, the subject delineator comprises an elongate web having con-
current characteristics of a sufficiently high modulus of elasticity for with-
standing buckling loads applied during static conditions along its longitudinal
axis during installation and a sufficiently low moment of inertia to establish
elastic character in an exposed section of said delineator to permit nondestruc-
ll~Z()~6
tive deformation upon impact by a moving object and subsequent immediate re-
storation to an original, upright orientation, said elongate web structure com-
prising a combination of random (or transverse) and longitudinally oriented
fibers imbedded in 20 to 40% (w) resin binder, said fiber combination being com-
prised of at least 7% but not more than 60% fiber in random arrangement to pro-
; vide transverse flexibility and tensile strength, and said longitudinal orienta-
tion of fiber comprising the remaining percentage of total fiber content to pro-
vide longitudinal rigidity during said static conditions.
As best shown in Figure 8 a removable, rigid-body casing 81 may be
positioned around a portion of the delineator structure 80. The effect of this
rigid-body casing is to reduce the length of the delineator exposed to buckling
forces during installation procedures. This reduced length decreases the
denominator of equation (1), thereby increasing the ultimate buckling load. It
is noted that since the length parameter of the referenced equation is squared,
any reduction in length greatly magnifies the increase in buckling load capable
of being withstood
Typical construction materials used for the rigid-body casing 81 would
be steel or other heavy-duty substances capable of withstanding buckling pres-
sures exerted by the delineator contained within the casing. Additionally, the
casing may be capped with an impactable substance which serves to disperse the
driving force along the top edge 83 of the delineator body 80. By utilizing
such a rigid-body casingJ the strength of the reinforcing rib material required
for installation is reduced.
Naturally, the preferred structure for the rigid casing would have the
inner surface conformed to the outer surface of the delineator body to be en-
closed. This would restrain any lateral movement and essentially eliminate that
enclosed section from the total length of the delineator subject to equation (1).
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llCI Z~36
The reinforcing rib structure located at the contacting face of the
various delineators illustrated herein may also provide protection for sign
materials affixed to the delineator face. As disclosed in Figure 2, the sign
material 21 will generally always be attached at the impacting surface of the
delineator 20. Without protective ridging, the sign surface would be exposed to
scraping or other destructive forces as it contacts the underside of cars or
other impacting objects. The lateral ridges protruding forward from the con-
tacting surface minimize contact with the actual sign surface attached thereto.
Such protection is especially important with less durable sign surfaces such as
reflective tape.
In connection with the affixation of sign surfaces to the subject
delineators, environmental protection against weathering effects must also be
considered. Mere attachment of reflective tape, for example, may have limited
life expectancy, particularly where the local environment includes rain with
freezing weather.
As a practical matter, water may locate behind the reflector coveringJ
and upon freezing, dislodge the material from the delineator surface. For this
reason, a small notch is located along a top edge 22 of the delineator surface.
The top edge of the tape is then recessed into the notch and protected from the
weathering conditions which would otherwise tend to detach the material.
An additional means of protecting the top reflector edge is to use a
protective cap 91 as shown in Figure 9. The top edge 92 of the reflective sur-
face 93 is retained within the enclosed region of the cap structure. In this
configuration, exposure to rain, snow and other adverse weathering elements are
minimized and reflector utility is preserved.
A supplemental benefit of the capped configuration is the protection
given to the top edge of the delineator during impact with vehicles. During
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11C};~8~
this impacting contact, the delineator will strike the underside of the vehicle
numerous times in attempting to restore itself upright. After repeated occur-
rences, the top edge of the delineator will tend to fray or otherwise degrade.
By using a thermoplastic cap having impact resilience and resistance to ultra-
violet radiation, the top edge is protected from such abrasion. Typically, such
a cap is fitted after placement of the delineator 90 into the ground, since the
installation driving force is preferably applied to the rigid top edge of the
delineator body.
Although the preferred forms of the invention have been herein des-
cribed, it is to be understood that the present disclosure is by way of example
and that variations are possible without departing from the scope of hereinafter
claimed subject matter.
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