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
  • E01F7/00—Devices affording protection against snow, sand drifts, side-wind effects, snowslides, avalanches or falling rocks; Anti-dazzle arrangements ; Sight-screens for roads, e.g. to mask accident site
  • E01F7/06—Anti-dazzle arrangements ; Securing anti-dazzle means to crash-barriers

Definitions

• the present invention relates to a glarefoil assembly for reducing headlight glare from on- coming traffic along a divided highway. More particularly, the invention relates to a glarefoil assembly having the novel capability of dis ⁇ sipating energy absorbed from various external sources throughout the entire assembly to decrease the possibility of deformation or failure of the assembly and thus substantially increase its life ⁇ time.
• Another attempt to solve the glare problem consists of an aluminum screen mounted to steel posts along the top of the median barrier.
• the screen is effective in eliminating headlight glare, but maintenance difficulties make this method impractical.
• the screens would often come loose and sag when buffeted by the wind and air currents created by passing automobiles. Pro ⁇ jecting objects from cars and trucks would often catch the screen and tear large holes or otherwise damage . the screen.
• Such screens were also subject to mischief in the form of thrown objects such as pop bottles or rocks which develop large holes in the screen, necessitating further maintenance. Of en in repairing even small holes in the screen, large whose sections of screen had to be replaced, thus adding to labor and material costs.
• the screens also created a barrier for police, ambulance and other emergency vehicles and personnel that need quick access across the high- way in times of accident or emergency. Often, large holes must be cut in the screen to enable quick response. This not only causes critical delays in treating accident victims and in responding to emergencies, but also necessitates additional cost in later reparations of the screen.
• glarefoils which are individually mounted on the top of the median barrier.
• These glarefoils sometimes referred to as paddles, are typically elliptical in shape extending up to 4 feet above the median barrier and are commonly made of polyethylene or other thermoplastic material.
• These glarefoils preserved cross access over the divider and solved some of the maintenance problems associated with the screens. Also, the flexibility of these glarefoils allows them to yield upon impact by protruding or thrown objects and then recover their original shape and position.
• each glarefoil is individually mounted to the median barrier by several bolts.
• the installation or removal of each glarefoil is timely and therefore costly.
• the thermo ⁇ plastic glarefoils become brittle when exposed to extreme temperatures and ultraviolet radiation from the sun.
• these glarefoils often break off at the bolt mountings when constantly buffeted by the wind or the everyday air currents from passing cars. Therefore, although the individual glarefoil system helped solve part . of the problem of absorbing energy from an occasional random impact they failed to deal with the problem of absorbing the everyday vibrational energy caused by wind and passing cars.
• the glarefoil assembly of the present inven ⁇ tion includes a plurality of light obstructing members and means for mounting them to the top 5 face of a base runner section to form an integral, modular structure.
• the bottom face of the base runner section is attached to the top of a median barrier.
• Succeeding base runner sections are mounted end to end in series to form a continuous glarefoil array along any distance desired. Since the base runner is installed in sections with several light blocking members mounted to each section, installation and removal is much more expeditious and inexpensive than the individual glarefoil system which requires individual mounting.
• the base runner also functions to receive vibrational energy which is absorbed by the light obstructing members. This is facilitated by con ⁇ structing the base runner and light obstructing members of flexible materials having mutually compatible elastic moduli, and by firmly securing the light blocking members to the base runner. When the light obstructing members are buffeted by the wind, some of the resultant vibrational energy Is transferred to the base runner which then also vibrates. This vibrational energy is transferred into the base runner in the form of wave motions or vibrations which are superimposed on other vibrations within the base runner from other light obstructing members, as well as rebound energy from the mounted ends of the base runner.
• the effect of superimposition of nonharmonic vibra ⁇ tions within the base runner results in a cancellation of part of the vibration energy as opposing waves traverse the base runner.
• This dissipation of vibrational energy relieves the glarefoil assembly of a portion of the vibrations within the glarefoil which would otherwise tend to concentrate at local points of stress where the light obstructing members are attached to the base runner, thus greatly reducing the risk of failure.
• the light obstructing members are rigid enough to stand upright with respect to the base runner, but are also flexible enough to yield to the impact of an object and then restore themselves to their original positions.
• the present invention is capable of absorbing and dissipating both impact energy and everyday vibrational energy, and as a result has a longer life expectancy.
• Figure 1 is a perspective view of the glare- foil assembly of the present invention, shown mounted to a median barrier.
• Figure 2 is an end perspective view of the glarefoil assembly shown in position along a divided highway.
• Figure 3 is a top plan view of the glarefoil assembly.
• Figure 4 is a bottom perspective view of the glarefoil assembly.
• Figure 5a is a cross-sectional view of a rectangular base runner of the glarefoil assembly with a segment of an upright light obstructing member and fastener shown in phantom lines.
• Figure 5b is a cross-sectional view of the base runner of the glarefoil assembly of Figure 4 taken along line 2-2, showing the Tri-Beam con ⁇ figuration of the base runner.
• Figure 6 depicts a slotted fastener used to assemble the glarefoil components.
• An integral part of the present invention includes the discovery that in a typical highway environment of passing high speed traffic, pulsating air currents develop which set the glarefoils into a state of mild vibration which may often be barely noticeable. Over extended periods of time, however, this seemingly trivial energy is concentrated at an immovable bolt location where the glarefoil is attached to the concrete median. Because of the extreme high modulus of the concrete and steel mounting bolt, the vibrational energy remains in the glarefoil until dissipated.
• the plastic of the glarefoil In contrast to the steel bolt and concrete of the median, the plastic of the glarefoil is flexible. At the point of attachment, therefore, there Is an extreme mismatch in modulus of elasticity which eventually leads to material failure around the bolt attachment location.
• the present Invention provides for partial translation of this vibrational energy out of the glarefoil and Into an elongated base member to thereby reduce the degree of vibrational movement at mounting bolt locations. Furthermore, the effects of the transferred vibrational energy are reduced by the fact that this energy is propagated into the base member in the form of waves which superimpose over waves from other light blocking members and thereby cause a partial cancellation or "interference" of superimposed waves.
• the attachment of a plurality of light obstructing members to a single base member permits the obstructing members to cooperatively reduce the actual vibrational energy developed in the base member, as compared to vibrational energy which would require dissipation if each obstructing member were attached to an independent and separate base member alone.
• a synergistic effect arises wherein the benefit exceeds the sum of the individual contri ⁇ butions made by the inventive structure. Mathematically, this could be illustrated in a glarefoil assembly with four blades attached to a single base member in the following" manner.
• This interference pattern is specifically facilitated by matching the compliance of the base member with that of the glare blades. This tends to reduce reflectional vibrations such as experienced by the conventional plastic glare blade as it vibrates against a rigid concrete median barrier.
• FIG. 12 An embodiment of this glarefoil assembly is generally designated 12 in Figures 1 and 2.
• Elongated light obstructing members 16 (also referred to herein as glare blades) are mounted to an elongated base runner section generally designated 13 at the top face 14a thereof, with angular support plates 26 providing the means for rigid attachment thereto.
• the bottom face 14b of base runner 13 is attached to a median barrier 10 along a divided highway represented by traffic lanes 30 and 32.
• Angular support plates 26 operate as rigid attachment means between the glare blades 16 and base runner 13. Although the figures illustrate the use of pop rivets 27 and 28, it will be noted that angular support plates 26 could be directly epoxied to glare blades 16 and base runner 13. Also, it will also be apparent that where minimal impact or vibrational energy is expected, glare blades 16 could be directly epoxied to top face 14a of base runner 13 without the need for angular support plates 26. Typically, angular support plates 26 are made of aluminum and add strength to the assembly as well as facilitate the transfer of vibrational energy as will be explained later. Other rigid metals or plastics could be used, provided they meet the strength requirement and facilitate the referenced energy transfer to the base runner section.
• Strengthening ribs 18 located at the edges of glare blades 16 provide rigidity and form an I-Beam configuration with the web section 42 of the glare blades 16. (See Figure 3) As best shown in Figures 1, 2 and 4, the ends of strengthening ribs 18 interlock with slots 34 in securing ribs 20a located at the edges of base runner 13. Securing ribs 20a extend upward from top face 14a and provide extra contact of glare blades 16 with base runner 13 in better securing glare blades 16 thereto. Securing ribs 20a also provide a more efficient energy path for the transfer of vibrational energy from glare blades 16 to base runner 13, as will be explained later.
• reinforcement ribs 20b which are also located at the edges of base runner 13 and extend downward from bottom face 14b.
• a spacing means such as rib 24 located in the center of bottom face 14b cooperates with reinforcement ribs 20b to displace the bottom face 14b from the median barrier 10 and thereby accommodate the heads 29 of pop rivets 28 In the space therebetween, while at the same time providing a rigid mounting site.
• an object such as a washer may also be used as the spacing .means 24 to enable rigid attachment of the base runner 13 against median barrier 10 and provide a space to accommodate pop rivet heads 29.
• Base runner section 13 is of sufficient length to permit a substantial receipt of vibrational energy from attached glare blades 16.
• the present inven ⁇ tion provides for dissipation of vibrational energy throughout the glarefoil structure, and particularly into the base runner.
• the transfer of vibrational energy from glare blades 16 to base runner 13 is facilitated by making the glare blades, the base runner section arid the angular support plate 26 or other attachment means of materials whose physical characteristics enhance their capability to transfer vibrational energy.
• Elastic modulus and moment of inertia are two such physical characteristics which, can be exploited to more easily effect such a transfer.
• the vibrational energy is carried directly into the base runner in accordance with well known wave propagation theory.
• the second element of moment of inertia its use in the present structure is primarily for the purpose of developing rigidity to improve the support and resilience of the glare blade and base member portions of the glarefoil assembly.
• This more rigid structure tends to enhance the propagation of vibrational waves in the same manner that a taut string or rubber band has * better wave transmittal characteristics than a loose string.
• the use of ribs and other reinforcing structure which increase moment of inertia operate to improve resilience and trans- mittance of vibrational energy.
• the glare lades 16 and base runner 13 are made of fiber ⁇ glass or fiber reinforced plastic.
• the elastic modulus of fiberglass composite (approximately 1-6 million) is well adapted for such a glarefoil assembly because It has inherent rigidity and weatherability to remain functional, yet it can be structured to withstand random impacts from passing vehicles or objects without incurring immediate need for maintenance.
• Such fiberglass composite material can also be pultruded or other- wise formed into various geometric cross-sections to maximize opposing characteristics of flexi ⁇ bility and rigidity at minimal cost. See for example, U.S. Patent 4,092,081.
• moment of inertia can also be used to effect a better transfer of vibrational energy within glarefoil assembly 12.
• FIG. 5a shows such a configuration, that of an I-Beam or modified Tri-Beam.
• the I-Beam configurated base runner 13 of Figure 5b have a vertical mode of vibration as indicated by arrows 4 and 4' , but it also develops a rotational mode of vibration indicated by arrows 5 and 5'.
• This configuration is achieved by having a thin web section 40, in conjunction with securing ribs 20a and reinforcement ribs 20b.
• the web section 40 has a low moment of inertia which improves flexibility.
• the strengthening ribs 18 of glare blades 16 also employ this concept.
• Strengthening ribs 18 form an I-Beam configuration with thin web section 42, as best seen in Figure 3.
• the additional vibrational modes created by joining strengthening ribs 18 to web section 42 enhances translation of multiple modes of energy transfer to the base runner section. This method of energy transfer also avoids excessive concentration of stress at local sites and therefore reduces the rate of wear toward failure.
• Another important feature of the glarefoil assembly 12 is the use of securing ribs 20a which provide improved rigid contact between the glare blades 16 and the base runner 13. Not only does the extra contact provide enhanced stability to the upright member, but it also provides more effective contact area between the ribbed portions of the respective glare blades 16 and base runner 13. This integral contact between the more rigid rib portions tend to make the subject glarefoil assembly respond to energy vibration as a single, integral unit.
• a slot extending across face 14a to accomodate the entire end of a glare blade 16 Is also possible. Such a slot would provide even more integral contact by glare blade 16 with base runner 13 and effect an even better transfer of vibrational energy therebetween.
• angular support plates 26 In providing additional contact and support with glare blades 16 and base runner 13, angular support plates 26 also provide an additional energy path for dissipating vibrational energy from the glare blade 16 to the base runner 13.
• glarefoil assembly 12 to median barrier 10 can be accomplished in many different ways.
• One simple method is to drill holes in the concrete median barrier and insert an iron stud 36. Holes 22 in corresponding position to the studs 36 are drilled in the base runner 13. The studs 36 are then inserted info holes 22 and the assembly 12 is then firmly secured to median barrier 10 by means of washers and steel nuts 38.
• a possible alternative method of installation would be to epoxy the ends of the base runner 13 or ribs 20b and 24 directly to the median barrier 10.
• each glare blade may vary, depending on the width of the blade and the relative angle of implacement with respect to the longitudinal axis of the base runner. It should be apparent that wider glare blades will enable greater spacial separation. Furthermore, the maximum spacial displacement between adjacent glare blades will be a function of blade orientation, since the blades must effectively block out all opposing headlight glare during close visual proximity between passing cars.
• Thickness of ribs on base .64-1.27cm Thickness of web section .23-.64cm

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Bridges Or Land Bridges (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Polarising Elements (AREA)
• Liquid Crystal (AREA)

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• 1982
  • 1982-03-17 EP EP82901333A patent/EP0102951B1/de not_active Expired
  • 1982-03-17 WO PCT/US1982/000360 patent/WO1983003271A1/en active IP Right Grant
  • 1982-03-17 AU AU83907/82A patent/AU8390782A/en not_active Abandoned
  • 1982-03-17 DE DE8282901333T patent/DE3278213D1/de not_active Expired
  • 1982-03-17 AT AT82901333T patent/ATE32928T1/de not_active IP Right Cessation

Patent Citations (2)

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