MXPA97010381A - Base for a carret sign - Google Patents

Abstract

The present invention relates to a road sign comprising a cover (30) molded of suitable plastic and having an internal honeycomb configuration. A base plate (42) extends over the lower surface of the cover that covers the alveolar array and defines a plurality of chambers (38) internal to the cover. The plate is provided with a plurality of openings (50), each opening for a chamber (38). When the signal is installed, an adhesive material flows through the openings (50) and into the chambers (38). Before the adhesive hardens, fungiform configurations (58) are formed on the upper internal surface of the plate (42). The fungiform configurations (58) create a strong mechanical bond between the plate and the associated road surface. The lower, large surface area of the plate and the associated road surface. The lower, large surface area of the plate (42) also improves the binding of the signal to the road (5).

Description

BASE FOR A ROAD SIGNAL BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to an improved base for a road or roadway sign and more particularly to a base for a signal having improved pavement adhesion capabilities when used with conventional adhesives. 2. Description of the Prior Art Road signs have been used for a long time to designate bands of traffic road traffic and central lines of road. The initial shapes of road signs were constructed from a solid piece of ceramic material that has a high gloss or luster. Protrusions with ridges were formed on the bottom surfaces of these signals to increase the surface area for cooperation with a suitable adhesive material. In more recent times, road signs involved the use of thermoplastics for REF: 26556 to form signal covers. For purposes of manufacturing economies, these signals were not formed within solid structures similar to the initial ceramic signals. Preferably, these typically have a relatively thin wall with a series of internal ridges defining a plurality of chambers, very similar to a waffle or honeycomb configuration. An example of a signal of this kind is described in U.S. Patent No. D-267,933. In order to mold these signals, the flanges or walls of the chambers taper down to a narrow dimension on the road surface. This is necessary to provide a sufficient angle of inclination for the removal of the signal from the mold. These signals are installed by depositing a suitable adhesive such as bitumen or epoxy on the road surface and pressing the signal down into the adhesive. It has been found that a disadvantage of the above signals is that when the signal is pressed into the adhesive it exhibits a "cookie cutter" effect. Essentially, the narrow bottom surfaces of the walls of the chambers compress or press the adhesive up into the chambers which leaves little adhesive between the surfaces of the signal, background and road to firmly hold the signal. In order to improve the adhesion capabilities of the signals, a signal is known in which the flanges or walls of the internal chambers are initially formed with the tapered configuration, mentioned above. Then, in a separate manufacturing step, the bottom surfaces of the walls are technically deformed to have a cross section similar to a mushroom. This deformation essentially increases the bottom area of the walls and reduces the cookie cutter effect of the signal: The fungiformity of the walls also allows the adhesive to flow into the chambers and onto the tops of the fungiform surfaces providing which a mechanical union, increased between the signal and the adhesive. An example of a signal of this kind is disclosed in U.S. Patent No. 5,078,538 issued January 7, 1992 and assigned to the common assignee herein. While the signs, as just described, improve on the initial constructions, they are not without disadvantages.

Specifically, it has been found that signals having internal chambers sealed in their bottoms with pressure differences that the adhesive experiences between the ambient air pressure acting on the exposed cover of the signal and the internal air pressure for the chambers. The pressure inside the signal chambers increases remarkably, for example, if the signal is installed in cold and then heated later by high ambient temperatures. This differential procedure effect reduces the retention force in the signal. Another problem experienced by conventional signals is that a preferred adhesive material for installing the signals is the bitu en. The bitumen can easily be heated to a fluid state and empty on the pavement in puddles or all in locations where signals are desired. the signals can then be pressed into the puddles and the bitumen can be allowed to cool. Bitumen hardens quickly as compared to alternative adhesives such as epoxy. Nevertheless, a disadvantage of the bitumen is that it bitumen dramatically loses the bond strength of the adhesive with temperature. In this way, even with the improved signals of the type described in U.S. Patent No. 5,078,538, the surface area of the background of the typical signal is still not sufficient to create a sufficiently strong bond between the signal and the bitumen adhesive, particularly at elevated temperatures. Accordingly, it is desirable to provide an improved signal having an alveolar interior for strength, but not exhibiting a cookie cutter effect. In addition, it is desirable to provide such a signal that is resistant to eviction under the effects of air pressure differences between the ambient pressure and the internal pressure of the signal. Still further, it is desirable to provide such a signal with a base having a relatively large surface area for increased mechanical bonding with preferred adhesive materials such as bitumen.

BRIEF DESCRIPTION OF THE INVENTION The present invention improves upon the prior art by providing a road or roadway sign comprising a suitable molded plastic cover and having an internal cellular configuration. A base plate extends over the lower surface of the cover that covers the alveolar array and defines a plurality of chambers internal to the cover. The plate is provided with a plurality of openings, each opening for a chamber. When the signal is installed, the adhesive material flows through the openings and into the chambers. Before the adhesive hardens, the fungiform configurations are formed on the inner, upper surface of the plate. The fungiform configurations create a strong mechanical bond between the plate and the associated road surface. The lower, large surface area of the plate also increases the bond of the signal to the road.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other novel features and advantages of the invention will be understood by reading the following detailed description taken in conjunction with the accompanying drawings in which: FIGURE 1 is a cross-sectional view of a road signal cover of the construction of the known prior art; FIGURE 2 is a plan view of the bottom of a cover for a road sign constructed in accordance with the principles of the invention; FIGURE 3 is a cross-sectional, side view of a road sign cover and a base plate constructed in accordance with the principles of the invention and illustrated as being installed with the adhesive on the road surface; FIGURE 4 is a top plan view of the base plate shown in Figure 3; and FIGURE 5 is a cross-sectional, "side view of the base plate of FIGURE 4.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY Referring now to the drawings, and initially to FIGURE 1, a road sign cover, constructed in accordance with the prior art, is designated in general by the reference number 10. The cover 10 is shown as being installed on a surface 12 of a highway pavement 14 with a suitable adhesive 16. Internal to the cover 10 are a series of reinforcing beads 18 arranged in a honeycomb configuration and defining the chambers 20. In this example a signal technique above, the ridges 18 have been thermally deformed at their bottom surfaces to have a fungiform cross-section 22. By this configuration, the adhesive flows around and on the fungiform surfaces 22 of the ridges 18 and thereby creates a mechanical bond between the surface of highway 12 and cover 10. However, it can be seen from FIGURE 1 that the differential air pressure between ambient air pressure The pressure inside the chambers 20 can reduce the holding force on the cover of the signal 10 as the increased pressure inside the chamber 20 acts on the upper surfaces 24 of the cured adhesive. In addition, the bottoms 26 of the honeycomb surfaces 22 have relatively small surface areas. Therefore, the mechanical connection with the surface of the road 12 is somewhat limited.

Turning now to FIGURES 2 and 3 a signal cover constructed in accordance with the present invention is designated generally by the reference number 30 the cover 30 comprises a bottom surface 32 having a large central opening 34 in which a series of fully formed vertical rims 36 are arranged to define the individual cells or chambers 38. In a manner well known in the art, the upper surface 39 of the cover 30 may be provided with one or more reflective elements (not shown). At spaced, preselected intervals within the opening 34 are a plurality of reinforcements 40 adhered to the supports 40., as by ultrasonic welding for example, and cover of the complete opening 34, is a base plate 42. As seen in improvement in FIGURES 4 and 5, the base plate 42 is a relief member of tensile strength elongate, generally thin which is preferably formed with suitable reinforcement ribs 44. The reinforcement ribs 44 are located on the plate 42 so as not to interfere with the reinforcements 40 of the cover 30. In addition, the flanges 44 are sized and arranged for each one is in contact with a flange 36 extending downwardly of the cover 30. In this way, the flanges 36 and 44 cooperate to firmly support the surface 39 of the cover 30 against the loads of the tires. The flanges 36 and 44 are also preferably ultrasonically welded together. Whereby, the plate 42 fits within the opening 34 to form a continuous surface 46 with a bottom surface 32 of the cover 30. According to the invention, the plate 42 is provided with a plurality of aperture 50, the purpose of which will be described later. Referring again to FIGURE 3, the cover 30 with the base plate. 42 connected is illustrated as installed on a surface 52 of the pavement of the road 54 by a suitable adhesive 56. The adhesive 56 is preferably of a type such as bitumen having a fast cure time so that the installation of the signal It can be done with minimal disruption of automotive traffic. As FIGURE 3 illustrates, the condition of the adhesive 56 is such that a uniform layer 58 of the adhesive 56 is formed between the surface of the road 52 and the complete bottom surfaces 46 and 32 of the plate 42 and the cover 30, respectively. In addition, the adhesive 56 flows through the openings 50 of the base plate 42 and into the inner chambers 38 of the cover 30. Before the adhesive 56 hardens or cures, it assumes a fungiform configuration 58 within the chambers 38. It can now be seen that a mounting of a cover 30 and a base plate 42 according to the invention offers considerable resistance to forces such as impact forces of the tires that tend to dislodge or loosen the surface assembly of the pavement. The fungiform configuration 58 of the adhesive 56 in the openings 50 of the plate 42 provides substantial resistance to forces having a component directed normal to the pavement surface. In addition, the relatively large surface area of the plate 42 with a coextensive adhesive 56 offers considerable resistance to shearing or cutting forces as are common in the installed conditions of the signals. Furthermore, it can be seen that the plate 42, and not the adhesive 56, carries the effect of increased air pressure within the chambers 38. Therefore, unlike the previous signals having sealed chambers with adhesive, the present assembly The signal is also highly resistant to eviction under the effect of internal pressure forces that can be caused by high ambient temperature conditions. While the present invention has been described in connection with a preferred embodiment thereof, it will be apparent to those skilled in the art that many changes and modifications can be made without departing from the true spirit and scope of the present invention. Accordingly, it is proposed by the appended claims to cover all such changes and modifications as come within the true spirit and scope of the present invention.

It is "stated that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following:

Claims (8)

1. A road sign, characterized in that it comprises: a cover having an exposed upper surface, a lower surface portion and a central opening defined in the lower surface; a plurality of ridges formed, internal to the cover, the flanges are arranged to form discrete chambers within the cover; a base plate connected to the cover and covering the flanges and opening, the plate has a generally flat lower surface and a generally planar upper surface internal to the cover; and a plurality of openings formed by the plate, each opening communicating with a chamber defined by the flanges; where the adhesive flows through the openings and takes the mushroom shape on the upper surface of the plate inside the chambers when the signal adheres to the road surface.

2. The signal according to claim 1, characterized in that the cameras define an alveolar configuration.

3. The signal according to claim 1, characterized in that the cover also includes reinforcements projecting downwards from the cover for joining the base plate.

4. The signal according to claim 1, characterized in that the surface of the plate and the lower surface portion of the cover are arranged in a common plane.

5. The signal according to claim 1, characterized in that the flanges are integrally formed with the cover.

6. The signal according to claim 1, characterized in that the base plate is provided with reinforcement ribs that extend vertically upwards from the surface of the top plate.

7. The signal according to claim 3, characterized in that the base plate is provided with reinforcement ribs projecting upwards and the rims of the base plate are configured to project within the cover in a spaced relation to the reinforcements.

8. The signal according to claim 6, characterized in that the selective flanges of the cover and the selective flanges of the base plate are mutually aligned in a coupling with one another to support the cover on the base plate.