Concrete Sign Dart

The present application claims priority to U.S. Provisional Application No. 63/568,859 filed on Mar. 22, 2024, which is incorporated herein.

Roadway sign support systems are frequently installed in areas already covered with pavement. Installation of such signs generally requires removal of a portion of the pavement prior to placement of the sign dart which supports the sign support system. Following placement of the sign dart, cement or other binding material is added to the hole to secure the sign dart in place thereby providing stability to the sign support system. This multistep process requires extended exposure of the road crew to the dangers of passing traffic. Thus, a simple one step installation of the sign dart portion of sign support system through pavement material will enhance safety and reduce costs.

In one embodiment, the present disclosure provides a sign support system. The sign support system comprises a sign dart having a hollow shaft. The hollow shaft has an exterior, an interior, a first end and a second end. Between the first end and the second end, the exterior of the hollow shaft is free of outwardly projecting elements. The first end of the hollow shaft carries a cutter configured to cut a borehole through a pavement material. The resulting borehole has a diameter which frictionally engages the exterior of the hollow shaft. The second end of the shaft carries a plate having a central passageway in alignment with the interior of the hollow shaft.

In another aspect, the present disclosure provides a method of installing a sign support system. The method entails positioning a sign dart within a pavement material. The sign support system comprises a sign dart having a hollow shaft. The hollow shaft has an exterior, an interior, a first end and a second end. Between the first end and the second end, the exterior of the hollow shaft is free of outwardly projecting elements. The first end of the hollow shaft carries a cutter configured to cut a borehole through a pavement material. The resulting borehole has a diameter which frictionally engages the exterior of the hollow shaft. The second end of the shaft carries a mounting plate having a central passageway in alignment with the interior of the hollow shaft. Following attachment of a driver to the mounting plate, the method cuts a borehole though at least a portion of the pavement material by using the driver to rotate the hole shaft at a rate sufficient to permit the cutter to cut a borehole. The driver continues cutting the borehole until the mounting plate is positioned a desired location from the pavement material. The resulting borehole has a borehole wall which engages the hollow shaft and applies sufficient frictional engagement with the hollow shaft such that the sign dart is retained within the borehole without the use of additional binder material. As a result, the sign dart provides the foundation of the sign support system.

The drawings included with this application illustrate certain aspects of the embodiments described herein. However, the drawings should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art with the benefit of this disclosure.

The present disclosure may be understood more readily by reference to these detailed descriptions. For simplicity and clarity of illustration, where appropriate, reference numerals may be repeated among the different figures to indicate corresponding or analogous elements. The following description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may have been exaggerated to better illustrate details and features of the present disclosure. Also, the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting except where indicated as such.

Throughout this disclosure, the terms “about”, “approximate”, and variations thereof, are used to indicate that a value includes the inherent variation or error for the device, system, or measuring method being employed as recognized by those skilled in the art.

The sign dartdisclosed herein overcomes the problems of the prior art discussed above. In particular, sign dartpermits the installation of the sign support systemwith only the use of a driver. Driveras depicted inis only one example of a drive device that would be suitable for engaging sign dartand driving it into and through pavement. The mechanism which engages drivercan be any convenient drilling mechanism capable of being secured to sign dartor driverand imparting rotational movement while applying a downward force sufficient to drive sign dartthrough a solid surface such as concrete, concrete with rebar, solid rock, coral, limestone, cement, asphalt, chip and seal substrate or other substantially solid surface similar to a road surface. For the remainder of this disclosure, such materials are referred to as “pavement.” Thus, sign dartnot only provides the foundation for several different types of sign supporting shafts but also performs the drilling operation normally carried out by a separate tool.

With reference to, sign dartincludes a hollow shaft. Hollow shafthas a length sufficient to provide stability to sign dartand any supported sign postand signfollowing installation of sign dartthrough the pavementand into the ground, i.e. subsurface soil. Hollow shafthas an exterior surfaceand an interior surface. The length of hollow shaft, as measured from first endto second end, may range from 24 inches to 48 inches or longer if necessary to provide the requisite stability. Typically, hollow shaftwill have a length between 30 inches and 40 inches. For most installations, a length ofinches toinches will suffice. Hollow shaftmay optionally include a first pair of opposing holesproximate to second end. Opposing holeswill generally be within 0.25 inch to 1.5 inches of second end. More typically, opposing holeswill be within about 0.5 inch to 1 inch of second end. In many embodiments, opposing holeswill be within 0.75 inch of end. A second pair of opposing holesare also positioned proximate to second end. Opposing holesare located about 1.5 inch to 2.0 inch from second end. Typically, opposing holesare located 1.75 inch from second end. In general, holesandare configured to receive a bushing. During installation of a drop-in sign postin shaft, hollow bushingspass through shaftand through holeslocated in sign post. Bolts, passing through bushingsand secure sign postin hollow shaft. The interaction of hollow shaft, sign post, bushingsand boltsprovide a highly stable sign support system. Typically, hollow bushingswill be steel bushings; however, any material having the necessary resilience for the environment of use will suffice. One exemplary embodiment of a suitable hollow bushingis depicted in.

First endof hollow shaftcarries a cutter. Attachment of cutterto first endmay be by any convenient means including welding or a threaded interface between the two components. Cutteris configured to drill through pavementand produce a boreholepassing through the surface of pavement. The configuration of cutterdepicted is merely exemplary as other configurations may be used. In general, rotation of sign dartby any convenient device while applying sufficient downforce will enable the formation of a boreholeby cutter. Therefore, cutterwill have sufficient hardness to produce the desired borehole through pavement. Typically, cutterwill be hardened steel and may include a titanium carbide bit. Cutterhas a cutting diameter which corresponds to or is slightly larger than the external diameter of shaft. Typically, the diameter of cutterwill be about 1% to about 2.5% larger than the diameter of shaft. In most instances, the diameter of cutterwill be about 1.5% to about 2.2% larger than the diameter of shaft. Generally, the diameter of cutterwill be about 1.8% larger than the diameter of shaft. For example, if hollow shafthas an exterior diameter of 3.5 inches, then a typical diameter for cutterwill be 0.0625 inch ( 1/16 inch) greater than the exterior diameter of hollow shaft. Thus, the diameter of cutterwill be about 3.5625 inches. In some embodiments, cutterwill erode away during the drilling process such that cutterhas an outer diameter consistent with the diameter of hollow shaft. Cuttermay optionally include a passageway. Passagewayallows cuttings produced during formation of boreholeto pass into the interiorof hollow shaft.

Second endof hollow shaftcarries a plate. Platehas a central openingaligned with the interior of hollow shaft. Plateis configured to be engaged by driverto permit drilling of a borehole through the pavement. The example driverdepicted inis configured to engage plate; however, other configurations are also contemplated. Plateis configured for use with both drop-in sign posts,, as well as with a multi-directional slip base breakaway systemas depicted in. Thus, platewill have a generally triangle configuration with slotsat each point of the triangle. As depicted in, the sign post support portion of a conventional slip base breakaway system carries a corresponding upper platewith corresponding slots. Joinder of lower base plateto upper plateis typically achieved using nuts, boltsand shimsas necessary. Multi-directional slip base breakaway systemalso includes an upwardly projecting sign postsuitable for supporting a sign. To accommodate drop-in sign posts, central openingwill generally be configured to receive a conventional sign post. As such, central openingwill in most instances have a length and width of about 2.625 inches. However, the size of plateand central openingmay vary depending on the application of sign dart.

As depicted in, hollow shaftis free of outwardly projecting elements between first endand second end. As previously noted, cutterhas a diameter which corresponds to or is slightly greater than the external diameter of shaft. Thus, the resulting borehole will have a diameter which generally corresponds to or is slightly greater than the external diameter of shaft. As a result, shaftwill be in frictional engagement with the internal diameter of the resulting borehole. This frictional engagement is sufficient to support sign dartand any subsequently attached sign posts or multi-directional slip based breakaway systemsin a stable, fixed manner. Thus, sign dartdoes not rely upon threads, flanges or other outwardly projecting elements to provide for formation of the borehole or retention of sign dartafter installation.

Since the exterior of shaftis free of external protrusions, threads, fins or other devices, retention of sign dartresults only from frictional engagement of hollow shaftwith the surrounding pavement. To be clear, retention of sign dartin place does not require the use of binder material such as cement, asphalt or other affixing material. If shaftpenetrates beyond pavement layer, then frictional engagement of shaftwith the subsurface soilprovides sufficient frictional engagement to stabilize and retain sign dart in place. As a further benefit of the frictional engagement and retention of sign dart, and any subsequently supported multi-directional slip base breakaway systemor other sign post, sign darteliminates the need to add cement or other binder material to the hole in which sign dartis secured. Thus, retention of sign dartwithin pavementand subsurface soilrelies solely upon frictional engagement between sign dartand pavementand subsurface soil.

With continued reference to the FIGS., improved sign dartalso provides an improved method of installation. The method of installing sign dartdoes not utilize cement or other binding agents to retain sign dartin the pavement or the subsurface soil below the pavement.

A rotational drive mechanism, not shown, rotates driverwhich engages or is attached to plate. Any convenient rotational drive mechanism, e.g. a hydraulic driver, suitable for applying rotational force will suffice in this operation. As depicted in, driverincludes three side beams. Each side beamhas a notchat a first end and a pivotal armcarried at the second end of beam. Driveralso includes a top plateand an attachment pointwhich may be engaged by any suitable rotation drive mechanism. As can be seen in, driveris configured to mate to the triangular configuration of lower base platecarried by shaft. Further, driverhas notcheswhich corresponds to notchesof base plate. Thus, drivermay be temporarily joined to base plateusing nutsand boltsor the operator may rely solely on the interaction of side beamsand pivot armswith base plateduring drilling operations. In the event that base plateis square instead of triangular, then driverwill have one additional beamand pivotal armbut will otherwise work in the same manner as described above.

Operation of the rotational drive mechanism with driver installed on base platerotates sign dartand applies downward force to sign dartsuch that cutterbegins cutting through pavementthereby forming borehole. Alternatively, the operator of the drive mechanism initiates rotation of driverto begin the drilling operation and the operator applies downward force such that cutterbegins cutting through pavementto form borehole. During drilling, cuttings formed by cutterpassing through pavementand subsurface soilmay pass through passagewayinto the interior of hollow shaftor to the exterior of hollow shaft. To the extent that cuttings pass to the exterior of hollow shaft, those cuttings further enhance the frictional engagement of hollow shaftwith the interior of borehole.

Driving of sign dartinto and through the pavementcontinues until plateis within about 3 inches of the upper surface of the pavementwith openingsandbeing above ground level. Thus, if pavementdoes not extend the full length of shaftand cutter, cutteralso forms boreholein the subsurface soil. At this point, hollow shaftis in contact with the interior of the resulting boreholein pavementand if present the subsurface soil. Following positioning of sign dartin borehole, drivermay be removed and either type of sign post positioned within or secured to sign dart.

Because cutterhas a cutting diameter which is equal to or slightly larger than the exterior diameter of hollow shaft, the resulting interface between boreholeand exterior surfaceof shaftproduces sufficient frictional engagement to retain sign dartwithin the boreholein a stable manner. The frictional engagement is sufficient to also support the subsequent attachment of sign postwith signas part of a multi-directional slip base breakaway system. Alternatively, a simple drop-in postmay be positioned within openingand the interior of hollow shaft. When using a drop-in post, retaining bolt, will normally be positioned through opposing holesand a corresponding hole(s) in drop-in postas well as opposing holesand corresponding hole(s) in drop-in-postthereby retaining drop-in postwithin hollow shaft. As noted above, bushingswill commonly be placed within holesandprior to placement of bolts. Retention of a multi-directional slip base breakaway systemto plateand sign dartwill be achieved using nuts, bolts and shims as required to joint upper plateto base platethereby providing the desired break-away system characteristics. In the break-away system, upper platesupports post.

Thus, the described method for installing sign dartdoes not require the use of a separate boring system to prepare a borehole for installation of sign dartat the signage location. Further, formation of the borehole and positioning of sign dartwithin the borehole occurs simultaneously. The simultaneous formation of the borehole and positioning of sign dartgenerates a frictional engagement between the pavement and/or subsurface soil and hollow shaftsufficient to retain sign dartwithin the borehole with sufficient stability to support the subsequently attached sign. As a result, an additional step of applying cement or other binding agent to stabilize and retain sign dartwithin the borehole is not required. Thus, the method of installing sign darteliminates two steps currently required when installing roadside signage. Specifically, the described method does not require an initial borehole to receive sign dartand does not utilize cement or other binding agent to retain sign dartin the borehole.

Other embodiments of the present invention will be apparent to one skilled in the art. As such, the foregoing description merely enables and describes the general uses and methods of the present invention. Accordingly, the following claims define the true scope of the present invention.