FIELD OF THE INVENTION

This invention relates generally to delineators that are used to control vehicle traffic on roadways and the like. The invention also relates to associated articles, systems, and methods.

BACKGROUND

Traffic delineators are known. Delineators are typically used on or near roadways or other paved or unpaved surfaces where automobiles, trucks, or other motorized or unmotorized vehicles travel. Often a series of delineators are arranged along a road, lane, or path so as to highlight or increase its visibility for the benefit of vehicle operators. FIG. 1 is an idealized perspective view of a roadway 110 along which delineators 112 have been placed to mark the path or direction of the roadway. Delineators can also be used in construction work zones to help guide vehicles along rerouted paths that may be unfamiliar to the vehicle operators. Perhaps because delineators can be used to direct or "channel" traffic in a given direction, they are sometimes also referred to as channelizers.

In some cases, delineators may be used in applications where visibility from only one direction is considered important. In other cases, e.g., when placed between lanes of traffic that move in opposite directions, it may be important for the delineator to exhibit high visibility from both such directions. In still other cases, such as at intersections, it may be important for the delineator to exhibit high visibility from four or more different directions, e.g., north, south, east, and west.

An example of a known delineator design is simply a post attached to a base. For improved visibility, the post may comprise high visibility materials. For daytime visibility, the post may be fabricated from bright diffuse materials, such as white or orange paint. For nighttime visibility, retroreflective sheeting may be wrapped around a portion of the post. Retroreflective sheeting has the characteristic of directing incident light back in the general direction from which it came, regardless of the angle at which the light impinges on the surface of the sheeting. Thus, as a vehicle approaches a roadway sign or other structure on which a retroreflective sheet is mounted, light from a vehicle headlamp may impinge on the sheeting, which then reflects the light back in the general direction of the headlamp. The retroreflection occurs in a small but finite angular cone, which cone encompasses the eye of the vehicle operator so that the operator perceives the sign as being conspicuously bright and highly visible.

FIGS. 2 and 3 are provided for background purposes to exemplify two angles that may have some significance when discussing retroreflective sheeting, or other reflective sheeting. FIG. 2 is a top view of a vehicle 210 traveling in a direction 212 along a roadway 214. Reflective sheeting 216 is provided near the side of the road. Sheeting 216 is assumed to be flat and planar, and the axis 218 is perpendicular to the plane of the sheeting. (In cases where the reflective sheeting is not flat, each portion of the sheeting may be considered to be flat if the size of the portion is small enough.) Axis 220

represents the direction along which light from the vehicle headlamp impinges upon the sheeting 216. The angle β between the axes 218 and 220 is referred to as the entrance angle for the light. A side view of this situation is shown in FIG. 3, where the vehicle headlamp (or other light source) is shown separately and labeled as 310, and the eye of the vehicle operator (or other observer) is shown separately and labeled 312. An axis 314 extends directed between the headlamp 310 and the sheeting 216. Another axis 316 extends between the sheeting 216 and the observer 312. The angle a between the axes 314, 316 is referred to as the observation angle.

Due to their proximity to moving traffic, delineators are occasionally struck by moving vehicles. Some delineators include one or more design features that allow them to withstand such vehicle strikes. For example, some delineator designs allow the delineator to deflect by as much as about 90 degrees in response to a sufficient deflecting force, and then to return to its upright position after the force is removed.

BRIEF SUMMARY

We have developed improved delineators capable of withstanding vehicle strikes and returning to their upright position.

Some of the disclosed delineators include a delineator body, a ball-and-socket joint, and a resilient rod. The ball-and-socket joint may be disposed to promote deflection of the delineator body in response to a deflecting force. The resilient rod, which may comprise steel, couples to the delineator body and to the ball-and-socket joint, and is adapted to restore the delineator body to an upright position after removal of the deflecting force. An elastic grommet, which may comprise rubber, is also preferably included that connects the rod to the delineator body. The ball-and-socket joint may allow the delineator to deflect equally in all directions, or preferentially in a preferred deflection plane.

The present application therefore discloses, inter alia, delineators that include a delineator body, a ball-and-socket joint disposed to promote deflection of the delineator body in response to a deflecting force, and a resilient rod coupled to the delineator body and the ball-and-socket joint. The resilient rod is preferably adapted to restore the delineator body to an upright position after removal of the deflecting force.

The delineator may also include an elastic grommet that connects the rod to the delineator body. The grommet may be configured to cover a portion of the rod proximate the ball-and-socket joint. The grommet may also be visible through an aperture provided in the delineator body. The grommet may be composed of vulcanized rubber or other suitable elastic, durable materials.

The delineator may also include a base coupled to the delineator body and adapted to secure the delineator to a pavement surface. In some cases, the ball-and-socket joint may be mounted in the base.

The resilient rod has a first and second end, and the first end may be disposed within the delineator body, and the second end may extend beneath the base. The rod may also pass through the ball-and-socket joint. The rod, which may comprise steel or other resilient material, may have a circular cross sectional shape, or other suitable shape.

The ball-and-socket joint may be characterized by a maximum pivot angle that varies substantially as a function of azimuthal angle φ. In some cases, the maximum pivot angle may be greatest at an azimuthal angle that also corresponds to a direction of greatest visibility of the delineator. In alternative embodiments, the ball-and-socket joint may be characterized by a maximum pivot angle that is substantially constant as a function of azimuthal angle φ.

Preferably, the delineator includes a reflective sheet applied to the delineator body in some fashion. In some cases, the delineator body may have a core/shell construction, and the reflective sheet may be applied to the core. The shell of such a construction may have one or more apertures formed a window region through which a portion of the reflective sheet is visible. In some cases, the shell may be configured to cover one or more edges of the sheet so that the sheet cannot be easily removed from the delineator by vandals.

Related methods, systems, and articles are also discussed.

These and other aspects of the present application will be apparent from the detailed description below. In no event, however, should the above summaries be construed as limitations on the claimed subject matter, which subject matter is defined solely by the attached claims, as may be amended during prosecution.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of a roadway with delineators positioned along the roadway;

FIG. 2 is a top view of a vehicle on a roadway encountering a reflective sheet; FIG. 3 is a schematic side view of selected elements of the arrangement depicted in

FIG. 2;

FIG. 4a is a schematic elevational view of a delineator having a bounceback mechanism;

FIG. 4b is a schematic elevational view of the delineator of FIG. 4a from a different perspective;

FIG. 4c is a schematic sectional view of the delineator of FIG. 4a along the lines 4c-4c;

FIG. 4d is a schematic sectional view similar to FIG. 4c but where the delineator design has been modified;

FIGS. 5a and 5b are schematic elevational views similar to FIGS. 4a and 4b, respectively, but where certain key dimensions of an exemplary embodiment are provided;

FIGS. 6a and 6b are schematic elevational views of delineators with bounceback mechanisms and subjected to deflecting forces;

FIG. 7a is a schematic elevational view of an exemplary delineator having a bounceback mechanism;

FIG. 7b is a close-up view of the delineator of FIG. 7a, where additional internal components are depicted for clarity;

FIG. 7c is a schematic elevational view of the delineator of FIG. 7a from a different perspective; FIG. 7d is a close-up view of the delineator of FIG. 7c, where additional internal components are depicted for clarity;

FIGS. 8a and 8b are schematic sectional views of a ball-and-socket joint capable of wide-angle deflection in two orthogonal planes;

FIGS. 9a and 9b are schematic sectional views of a ball-and-socket joint capable of smaller angle deflection in two orthogonal planes;

FIGS. 10a and 10b are schematic sectional views of a ball-and-socket joint capable of small angle deflection in one plane and wide-angle deflection in a second orthogonal plane;

FIG. 1 la is a perspective view of a deflection hemisphere, showing that any given deflection can be characterized by a polar angle Θ and an azimuthal angle φ;

FIG. 1 lb is a perspective view of a deflection hemisphere showing the deflection range associated with FIGS. 8a and 8b, and FIGS. 9a and 9b; and

FIG. 1 lc is a perspective view of a deflection hemisphere showing the deflection range associated with FIGS. 10a and 10b.

In the figures, like reference numerals designate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In FIGS. 4a and 4b, a delineator 410 having a bounceback mechanism is shown in schematic elevational view. The delineator includes a delineator body 412, a base 414, and a bounceback mechanism (the components of which are described below). For reference purposes, a Cartesian x-y-z coordinate system is also included in each figure. The z-axis of the coordinate system is parallel to a longitudinal axis 401 of the delineator. Note from the position of the x-y-z coordinate system that the view of FIG. 4b is orthogonally oriented relative to the view of FIG. 4a.

The bounceback mechanism of the delineator 410 includes several components which will now be described, but the reader will understand that in alternative

embodiments, not all of these components need be included. Several of the components are disposed in a lower portion 412b, rather than an upper portion 412a, of the delineator body 412. A ball-and-socket joint is preferably provided in a region 430 as a coupling between the delineator body 412 and the base 414 to promote pivoting motion. The ball- and-socket joint is not shown in FIGS. 4a and 4b, but similar ball-and-socket joints are shown in other embodiments described further below. The ball-and-socket joint may allow for a certain finite amount of deflection at the base of the delineator body 412. The limit of this deflection, referred to as a deflection range, may be the same for deflections in the y-z plane as for deflections in the x-z plane, or it may be different.

The bounceback mechanism also preferably includes a resilient rod 418. The rod

418 preferably resists permanent deformation when bent, but instead springs back to its original shape. In the embodiment of FIGS. 4a and 4b, the rod 418 is long and straight, but in other embodiments the rod may have other suitable shapes as desired. Although not visible in FIGS. 4a and 4b, the rod 418 preferably extends downward to the ball-and- socket joint. Furthermore, the rod 418 preferably has a first portion, e.g., an upper end portion thereof, that is anchored to the delineator body 412, and a second portion, e.g., a lower end portion thereof, that is anchored to the base 414 and/or to the ground or pavement beneath the base. By securing the rod in this way, deflecting forces exerted on the delineator body 412 cause a bending of the rod characterized by movement of the first portion but not the second portion. In cases where the rod is configured to pass through the ball-and-socket joint, much of this bending occurs at the ball-and-socket joint, in the region 430. The rod 418 is made of a resilient material such as steel, or other known metals, plastics, or other suitable resilient materials that allow the rod to bend when a deflecting force is applied to the delineator, but to spring back to its original shape when the deflecting force is removed so as to return the delineator to its upright position. The rod may have a circular cross-sectional shape (in the horizontal or x-y plane) or a non- circular cross-sectional shape. A circular cross-sectional shape has an advantage of allowing the same degree of bending regardless of the plane of deflection, e.g., bending in the x-z plane, bending in the y-z plane, and bending in any other azimuthally oriented vertical plane.

In the embodiment of FIGS. 4a and 4b, only one resilient rod is included in the delineator design. In alternative embodiments, the delineator may include a plurality of resilient rods, each of which is configured to bend when the delineator body is deflected and then to spring back to its original position so as to return the delineator to its original upright position. When multiple resilient rods are used, the restoring force provided by each rod may be less than the restoring force provided by a rod in a single-rod delineator design. The bounceback mechanism of delineator 410 also preferably includes an elastic grommet 416. The grommet 416 preferably holds the resilient rod 418 and constrains it from acute bending and eventual inelastic deformation or other damage. The rod 418 thus passes through the grommet 416, and the grommet preferably acts as a type of buffer or cushion to connect the rod to the delineator body 412, e.g. , at an upper end of the grommet as shown best in FIG. 4a. Set screws or any other known attachment mechanism may be used to attach the grommet to the delineator body. The upper end of the grommet 416 is also provided with protrusions 416a, 416b, which project out of an aperture 412c formed in the delineator body 412, although in alternative embodiments the protrusions 416a, 416b (as well as the aperture 412c) may be modified or even omitted if desired. The grommet 416 also has a lower end, which preferably attaches to, or is otherwise coupled to, the ball-and-socket joint. The grommet 416 may be provided with cuts or grooves 416c as shown, to promote flexing or for other purposes. The grommet may be made of vulcanized rubber, suitable polymer materials, or other known elastic materials.

A significant function of the disclosed delineators is to provide a structure that is highly visible to vehicle operators from one or more directions. Consequently, the delineator 410 preferably comprises high visibility materials and components. For example, some or all of the body 412 may be made of a brightly colored (e.g., white, orange, or other color) polymer or other suitable material, or brightly colored paints or other substances, including fluorescent materials or films, may be applied to the body 412 for enhanced visibility. In the embodiment of FIGS. 4a and 4b, a first reflective sheet 413 is provided on one side of the delineator body, and another reflective sheet 415 (see FIGS. 4b, 4c, 4d), which may be substantially similar to sheet 413 or may be different, may be provided on an opposite side to provide a bi-directional delineator. Shading is used in FIG. 4a to indicate the exposed portion of the sheet 413. The sheet(s) may have a striped pattern as shown in FIG. 4a, or any other desired pattern, or the sheet(s) may have no pattern at all, i.e., a spatially uniform appearance. The reflective sheets 413, 415 may provide high daytime visibility and/or high nighttime visibility. Sheeting that is retroreflective can provide high nighttime visibility. Retroreflective sheeting can be characterized by the sheeting's coefficient of retroreflectivity, which is typically measured in units of candelas per lux per square meter, or cd/(lux*m ² ). Retroreflective sheeting may in some cases have a retroreflective coefficient of at least 10, or at least 100, or at least 500 cd/(lux*m ² ) for head-on viewing (β = 0), but the retrorenectivity may decrease or otherwise change with increasing entrance angle. The amount of decrease as a function of entrance angle depends on design details of the retroreflective sheeting.

Although retroreflective sheeting from any vendor may be used, retroreflective sheeting sold by 3M Company is preferred. Such sheeting may include 3M™ Diamond Grade™ DG ³ Reflective Sheeting Series 4000, 3M™ Diamond Grade™ Conspicuity Markings Series 983, or 3M™ Diamond Grade™ Flexible Prismatic School Bus Markings Series 973, for example. The Series 983 product may be considered to provide enhanced retroreflectivity at long ranges, because its retroreflectivity is particularly high at very small observation angles a, which generally correspond to observation at large distances. The Series 4000 product, even though it also provides very good retroreflectivity at large distances, may be considered to provide enhanced retroreflectivity at shorter ranges, because its retroreflectivity decreases less than that of the series 983 sheeting as the observation angle a increases. Note that in addition to viewing distance, the observation angle a can also be affected by the vehicle size: in small vehicles, the distance from the vehicle headlamp to the vehicle operator's eye is generally smaller than for larger vehicles. Thus, at any given viewing distance, the operator of a small automobile, for example, will typically have a smaller observation angle a than the operator of a large truck or bus, for example. In addition to exhibiting differences as a function of observation angle a (FIG. 3), different retroreflective products also exhibit differences as a function of entrance angle β (FIG. 2). Thus, for example, the retroreflectivity of the series 983 conspicuity sheeting mentioned above decreases less (for a given observation angle) than that of the series 4000 sheeting as the entrance angle increases, and can thus be said to have a wider entrance angularity.

The delineator body 412 may be of single piece construction, or it may comprise multiple pieces, e.g. two halves, that attach or otherwise couple to each other to form a unified structure. The body 412 may have a bullet-like profile as seen in FIG. 4a from one azimuthal perspective, or it may have any other desired profile. The body may have a non-circular cross-sectional shape that may be considered to be flattened in one horizontal direction (the y-direction in FIG. 4a) or elongated in another horizontal direction (the x- direction in FIG. 4a), or it may have other non-circular cross-sectional shapes or a substantially circular cross-sectional shape. Flattening in the y-direction may provide a delineator surface that has less curvature than a circular cross-sectional shape of similar cross-sectional area, and this reduced curvature may help enhance the visibility of the refiective sheet by maintaining a smaller range of entrance angles for the reflective sheet for viewing along certain preferred directions, namely, the positive and negative y- directions as best seen in FIGS. 4c and 4d, which may correspond to the direction of a road and/or direction of travel of nearby vehicles.

The delineator body 412 is shown as having an aperture 412c through which a portion of the resilient rod 418 and the grommet 416 can be seen. This aperture may be modified if desired, e.g. , enlarged or reduced in size, or it may be entirely omitted from the delineator design.

The delineator body 412 may have a core/shell type construction as shown in FIG. 4c, or it may not, as shown in FIG. 4d. Thus, FIG. 4c is a schematic sectional view of delineator 410 along the lines 4c-4c in FIGS. 4a, 4b, showing a core/shell type

construction. Further description of core/shell delineator constructions, and advantages of such constructions, can be found in U.S. Patent Application 61/288,581 (Attorney Docket No. 65819US002), "Delineator With Core/Shell Construction", filed December 21, 2009, incorporated herein by reference. In FIG. 4c, the delineator body 412 is in the form of an outer shell with one aperture to reveal refiective sheet 413 and another aperture to reveal reflective sheet 415. This outer shell fits securely around an inner core 417, which forms a second part of the delineator body. The refiective sheets 413, 415 are adhered to or otherwise applied to an outer surface of the inner core 417. The apertures in the outer shell 412 are preferably sized to expose most of the surface area of the sheets 413, 415, but not portions at the peripheries thereof so that edges of the sheets are not exposed. The outer shell 412 thus covers at least some, and preferably all, of the sheet edges (labeled 413a for sheet 413 and 415a for sheet 415) so as to protect the sheets from being peeled off of the delineator body by vandals. The outer shell 412, inner core 417, and sheets 413, 415 are preferably sized so that the shell 412 is pressed tightly against the reflective sheets at the edges of the apertures (no gap between the shell 412 and the reflective sheets), again to prevent tampering by vandals.

FIG. 4d is a schematic sectional view similar to FIG. 4c but where the delineator design has been modified to have a simpler, non-core/shell type of construction. For example, the delineator of FIG. 4d may have a one-piece type of delineator body construction. In this case, the delineator body 412 forms a continuous shape in this cross- sectional view, and the reflective sheets 413, 415 are adhered or otherwise applied to the outer surface of this body. The body 412 may be of unitary construction, or it may include multiple pieces, e.g. two halves, that have been joined together.

FIGS. 5a and 5b are schematic elevational views similar to FIGS. 4a and 4b, respectively, but where certain key dimensions of an exemplary embodiment of delineator 410 are provided. Dimensions are given in millimeters. The reader will understand that these dimensions are only exemplary, and should not be construed as limiting.

FIGS. 6a and 6b are schematic elevational views of delineators with bounceback mechanisms that are being subjected to deflecting forces. The delineators may be the same or similar to delineators discussed in connection with FIGS. 4a-d. FIGS. 6a and 6b show the effect of flexibility of the delineator body (whether or not it has a core/shell construction) on deflection angles. The delineator of FIG. 6a has a delineator body 612 that is substantially rigid; the delineator of FIG. 6b has a delineator body 613 that has significant flexibility. The figures assume that a deflection force is applied to each delineator along the negative y-direction to deflect the upper portion of the delineator by an angle Θ1 relative to its original upright orientation. In each case, the lower portion of the delineator deflects by an angle labeled Θ2 relative to its original orientation. In exemplary embodiments, a ball-and-socket joint is disposed at or near the delineator body lower portion, e.g. , in the base to which it is attached. The figures are drawn such that the upper deflection angle Θ1 is the same in FIGS. 6a and 6b. However, due to the difference in flexibility of the delineator body, the lower deflection angles Θ2 are not the same. In the case of the rigid delineator body (FIG. 6a), the lower deflection angle Θ2 is

substantially the same as the upper deflection angle Θ1. However, in FIG. 6b, the lower deflection angle Θ2 is substantially less than the upper deflection angle Θ1 as a result of the bending of the delineator body 613. The smaller deflection angle Θ2 in FIG. 6b advantageously allows greater delineator deflection (at mid- and upper-portions of the delineator body) for a given deflection of the ball-and-socket joint, which is typically disposed at the base of the delineator.

The use of flexible materials for the delineator body can also be advantageous in situations when the delineator is completely run over by a vehicle wheel or tire. When the delineator body is flexible, a direct hit by a vehicle tire may press the delineator body flat to the ground, after which the delineator body may spring back to its original circular or non-circular cross-sectional shape, for example.

FIGS. 7a-d are different views of another exemplary delineator 710 having a bounceback mechanism similar to that described in connection with FIGS. 4a-d. A Cartesian x-y-z coordinate system is again shown in the figures for reference purposes. FIGS. 7a and 7b are views along the positive y-direction, with FIG. 7b being a close-up view showing some internal components for clarity. The effect of a deflection force along the positive x-direction is also shown, with the deflected delineator shown in phantom lines. FIGS. 7c and 7d are views along the negative x-direction, with FIG. 7d being a close-up view showing some internal components for clarity. The effect of a deflection force along the positive y-direction is shown, with the deflected delineator shown in phantom lines.

The delineator 710 includes a delineator body 712 pivotably coupled to a base 714 via a ball-and-socket joint 730. The delineator body comprises an upper portion 712a, a lower portion 712b, and an optional aperture 712c. The delineator body 712 is shown to have a bullet-like profile in the view of FIG. 7a, but other suitable profiles are also contemplated. Similar to delineator body 412, delineator body 712 may be of single piece construction, or may comprise multiple pieces (e.g., two halves, or more than two component pieces) attached or otherwise joined together. If desired, the delineator body 712 may have a core/shell construction, which may or may not be used to protect edges of reflective sheets that are applied to the delineator. The delineator body 712 is shown to have a narrower profile in the view of FIG. 7c than that of FIG. 7a, and to have two similarly sized reflective sheets 713, 715 provided on opposed sides of the delineator for bi-directional viewing, but other designs are also contemplated. For example, the delineator body 712 may be redesigned to have a simpler shape, such as a circular cylinder, and one or more reflective sheets may be wrapped completely around the cylinder to provide omnidirectional viewing. Alternately, the shape of the delineator body 712 shown in the figures may be maintained, and one of the sheets 713, 715 may be omitted for unidirectional viewing. In the embodiment shown in the figures, visibility is maximized along the positive- and negative y-directions, which would typically correspond to the direction of vehicular travel when the delineator 710 is mounted near a roadway. The delineator body 712 pivotably couples to the base 714 at the bottom of the body 712. The base is shown to be secured to the ground or pavement by bolts 738, but any other suitable attachment mechanism may be used. The base 714 includes a cup-like member 732 designed to extend into a correspondingly shaped depression in the ground or pavement, and designed to attach to a lower end of a resilient rod 718 as shown. In alternative embodiments, the cup-like member 732 may be omitted, and the rod 718 may be driven into the ground or pavement by itself to help secure the delineator in place.

A ball-and-socket joint 730 is shown connecting the delineator body 712 to the base 714. The joint 730 is shown as allowing a first finite amount of deflection θχζ in the x-z plane (FIG. 7a), and a second larger amount of deflection 9yz in the y-z plane. (The tilted or pivoted delineator shown in phantom lines in FIGS. 7a-d assume the delineator body is substantially rigid, and that the upper deflection angle at the top of the delineator body is the same as the lower deflection angle that at the bottom of the delineator body, but embodiments in which the delineator body is flexible, and wherein the lower deflection angle is substantially less than the upper deflection angle, are also

contemplated.) The larger deflection 9yz occurs in a plane that is aligned with, or otherwise corresponds to, directions of maximum delineator visibility (the positive and negative y-directions), which in turn may correspond to directions of vehicular travel. In other embodiments, the ball-and-socket joint may be designed to provide the same amount of deflection (such that θχζ = 9yz) for all planes of deflection.

The delineator 710 also includes a resilient rod 718, which may be the same as or similar to rod 418 discussed previously, and which resists permanent deformation when bent and springs back to its original shape so as to provide a restoring force to the delineator, returning it to its upright position after a vehicle strike. The rod 718 has an upper portion that is anchored to the delineator body 712 by an attachment member 734 as shown best in FIG. 7b. A central portion of the rod 718 is anchored to the delineator 712 via an elastic grommet 716, which may be similar to or the same as grommet 416 discussed above. A lower portion of the rod 718 is anchored to the base 714 via the cuplike member 732. Alternatively, the lower portion of rod 718 may simply be anchored to the ground or pavement, and the base 714 may likewise be anchored to the ground or pavement. The rod 718 is shown as passing through the ball-and-socket joint 730. With this arrangement, rotation or pivoting of the ball-and-socket joint causes bending of the resilient rod 718 in the vicinity of the ball-and-socket joint 730.

An elastic grommet 716 is also provided to hold a portion of the rod 718 and constrain it from acute bending and eventual inelastic deformation or other damage. The grommet 716 is shown to be visible through the aperture 712c, but it may be entirely enclosed within the delineator body 712 if the aperture 712c is omitted. Set screws, one of which is shown in FIGS. 7c and 7d (label 736) and another of which is provided on the opposite side of the delineator, may be used to secure the grommet 716 to the delineator body 712, or other suitable means, such as an adhesive or a friction fit may be used, for example. The grommet 716 may comprise vulcanized rubber or another suitable elastic material such as an elastic polymer.

FIGS. 8a-b, 9a-b, and lOa-b show schematic views of different ball-and-socket joints that may be used in exemplary bounceback mechanisms described herein. The ball- and-socket joint 830 shown in FIGS. 8a and 8b is capable of wide-angle deflection in two orthogonal planes (and in any deflection plane parallel to the z-axis). The ball-and-socket joint 930 shown in FIGS. 9a and 9b is capable of smaller angle deflection in two orthogonal planes (and in any deflection plane parallel to the z-axis). The ball-and-socket joint 1030 shown in FIGS. 10a and 10b is capable of small angle deflection in one plane and wide-angle deflection in a second orthogonal plane.

Thus, in FIGS. 8a and 8b, a joint 830 is provided that comprises a ball 830a and matching socket 830b. The socket 830b, as viewed in any cross-sectional plane, surrounds less than half of the ball 830a so that the ball can pivot relative to its

equilibrium or upright position by wide angles θχζ and 9yz in the x-z and y-z planes, respectively, where θχζ ¾ 9yz, and these angles may be as much as about 90 degrees to allow for a full 180 degree swing in delineator position from one deflection extreme to the other. One disadvantage of this approach is that the ball 830a may separate from the socket 830b, unless the delineator is provided with an additional mechanical coupling device such as a tie-rod/wire, or an elastic coupling such as a bellows structure, to prevent such decoupling.

In FIGS. 9a and 9b, a joint 930 is provided that comprises a ball 930a and matching socket 930b. The socket 930b, as viewed in any cross-sectional plane, surrounds more than half of the ball 930a so that the ball is not able to separate from the socket. A consequence of this design is that the ball is able to pivot relative to its equilibrium or upright position by angles θχζ and 9yz in the x-z and y-z planes, respectively, that are substantially smaller than the corresponding angles of FIGS. 8a and 8b. The joint 930 is assumed to be symmetrical such that θχζ ¾ 9yz, and these angles are substantially less than 90 degrees.

In FIGS. 10a and 10b, an asymmetrical ball-and-socket joint 1030 is provided that comprises a ball 1030a and matching socket 1030b. The socket 1030b, as viewed in one cross-sectional plane (see FIG. 10a), surrounds more than half of the ball 1030a so that the ball is not able to separate from the socket. However, in an orthogonal cross-sectional plane (see FIG. 10b), the socket 1030b surrounds less than half of the ball 1030a so that the ball can pivot relative to its equilibrium or upright position by a large deflection angle 9yz , which may be as much as about 90 degrees to allow for a full 180 degree swing in delineator position from one deflection extreme to the other in the y-z plane. In the orthogonal x-z plane, the ball is able to pivot relative to its equilibrium or upright position by an angle θχζ that is substantially smaller than 9yz. The joint 1030 is thus asymmetrical in design. An advantage of such a design is that the socket provides sufficient structure to hold the ball in position without separation, while also allowing large deflection angles, e.g., as much as 90 degrees, in at least one plane of deflection. The orientation of the ball- and-socket joint relative to the delineator body may be selected to provide a desired relationship between the plane of maximum deflection and one or more planes (or directions) of maximum visibility. For example, the ball-and-socket joint may be incorporated into a unidirectional or bidirectional delineator such that the direction or directions of maximum visibility are parallel to the plane of maximum deflection, which in turn may be parallel to the direction of vehicle travel.

FIGS. 1 la-c are diagrammatic representations to assist the reader in visualizing the range of deflections at the ball-and-socket joint that are possible with the joints depicted in FIGS. 8a-b, 9a-b, and lOa-b. Thus, FIG. 1 la is a perspective view of a deflection hemisphere 1110 whose center of curvature is situated at the origin of a Cartesian x-y-z coordinate system. The hemisphere is assumed to have an arbitrary radius, e.g., a radius of 1 unit. Any given deflection can be characterized by a polar angle Θ and an azimuthal angle φ, and each (θ,φ) pair can be represented by a point on the hemisphere 1110. (The absolute value of Θ can be used if needed to map negative values of Θ into positive values.) Note that azimuthal angles φ = 0 or 180 degrees correspond to deflections in the x-z plane, and azimuthal angles φ = 90 or 270 degrees correspond to deflections in the y-z plane.

FIG. 1 lb is a perspective view of the deflection hemisphere 1110, on which is drawn a first curve 1112 representing a possible deflection limit of the ball-and-socket joint of FIGS. 8a-b, and a second curve 1114 representing a possible deflection limit of the ball-and-socket joint of FIGS. 9a-b. If the ball-and-socket joints 830, 930 are of symmetrical design, then curves 1112 and 1114 are substantially circular shapes, similar to lines of latitude on a globe. The joint 830 may have deflections ranging from nominally zero deflection corresponding to the top of the hemisphere 1110 (i.e., the z-axis or Θ = 0) down to the boundary established by the curve 1112, which is nearly at the edge of the hemisphere itself. The joint 930 has a smaller range of deflection, from virtually zero at the top of the hemisphere 1110 down to the boundary established by curve 1114. The reader will understand that the curves 1112, 1114 are meant to be exemplary, and should not be considered as limiting.

FIG. 1 lc is another perspective view of the deflection hemisphere 1110, on which is drawn a curve 1116 representing a possible deflection limit of the ball-and-socket joint 1030 of FIGS. 10a and 10b. Thus, in the y-z plane, the curve 1116 approaches the edge of the hemisphere, i.e., about a 90 degree value of Θ. In contrast, in the x-z plane, the curve 1116 reaches a much smaller value of deflection Θ. The shape of curve 1116 is clearly seen to be asymmetrical, unlike the symmetrical curves 1112, 1114. Stated differently, the maximum pivot angle Θ associated with joint 1030 can be said to vary substantially as a function of azimuthal angle φ, while the pivot angle Θ associated with joints 830 and 930 can be said to be substantially constant as a function of azimuthal angle φ.

Unless otherwise indicated, all numbers expressing quantities, measurement of properties, and so forth used in the specification and claims are to be understood as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that can vary depending on the desired properties sought to be obtained by those skilled in the art utilizing the teachings of the present application. Not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, to the extent any numerical values are set forth in specific examples described herein, they are reported as precisely as reasonably possible. Any numerical value, however, may well contain errors associated with testing or measurement limitations.

Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the spirit and scope of this invention, and it should be understood that this invention is not limited to the illustrative embodiments set forth herein. For example, the reader should assume that features of one disclosed embodiment can also be applied to all other disclosed embodiments unless otherwise indicated. It should also be understood that all U.S. patents, patent application publications, and other patent and non-patent documents referred to herein are incorporated by reference, to the extent they do not contradict the foregoing disclosure.