Concrete sign dart

Abstract

A sign dart and a method for installing a sign dart wherein the retention of the sign dart in the ground relies solely on frictional engagement of the sign dart with a borehole passing into the ground.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Application No. 63 / 568,859 filed on Mar. 22, 2024, which is incorporated herein.BACKGROUND

[0002] 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.SUMMARY

[0003] 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.

[0004] 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.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 provides a side view of the sign dart.

[0006] FIG. 2 provides a top view of the sign dart.

[0007] FIG. 3 is a view of the sign dart positioned within the ground and supporting a sign.

[0008] FIG. 4 is a cut-away view depicting the components for joining a sign dart to a sign post as used in a drop in sign post configuration.

[0009] FIGS. 5A and 5B provide details on the connection of a post to the sign dart.

[0010] FIGS. 6A-6C depict an example sign dart driver.

[0011] FIGS. 7A-7B depict perspective views of bushings suitable for use in the sign support system.

[0012] FIG. 7C is a side view showing hidden lines depicting the passageway through the bushing of FIGS. 7A and 7B.DETAILED DESCRIPTION

[0013] 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.

[0014] 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.

[0015] 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.

[0016] The sign dart 10 disclosed herein overcomes the problems of the prior art discussed above. In particular, sign dart 10 permits the installation of the sign support system 5 with only the use of a driver 60. Driver 60 as depicted in FIGS. 6A-6C is only one example of a drive device that would be suitable for engaging sign dart 10 and driving it into and through pavement. The mechanism which engages driver 60 can be any convenient drilling mechanism capable of being secured to sign dart 10 or driver 60 and imparting rotational movement while applying a downward force sufficient to drive sign dart 10 through 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 dart 10 not 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.

[0017] With reference to FIGS. 1-4, sign dart 10 includes a hollow shaft 12. Hollow shaft 12 has a length sufficient to provide stability to sign dart 10 and any supported sign post 46 and sign 50 following installation of sign dart 10 through the pavement 32 and into the ground, i.e. subsurface soil 33. Hollow shaft 12 has an exterior surface 14 and an interior surface 16. The length of hollow shaft 12, as measured from first end 22 to second end 24, may range from 24 inches to 48 inches or longer if necessary to provide the requisite stability. Typically, hollow shaft 12 will have a length between 30 inches and 40 inches. For most installations, a length of 35 inches to 37 inches will suffice. Hollow shaft 12 may optionally include a first pair of opposing holes 18 proximate to second end 24. Opposing holes 18 will generally be within 0.25 inch to 1.5 inches of second end 24. More typically, opposing holes 18 will be within about 0.5 inch to 1 inch of second end 24. In many embodiments, opposing holes 18 will be within 0.75 inch of end 24. A second pair of opposing holes 26 are also positioned proximate to second end 24. Opposing holes 26 are located about 1.5 inch to 2.0 inch from second end 24. Typically, opposing holes 26 are located 1.75 inch from second end 24. In general, holes 18 and 26 are configured to receive a bushing 27. During installation of a drop-in sign post 46 in shaft 12, hollow bushings 27 pass through shaft 12 and through holes 48 located in sign post 46. Bolts 52, passing through bushings 27 and secure sign post 46 in hollow shaft 12. The interaction of hollow shaft 12, sign post 46, bushings 27 and bolts 52 provide a highly stable sign support system 5. Typically, hollow bushings 27 will be steel bushings; however, any material having the necessary resilience for the environment of use will suffice. One exemplary embodiment of a suitable hollow bushing 27 is depicted in FIGS. 7A-7C.

[0018] First end 22 of hollow shaft 12 carries a cutter 28. Attachment of cutter 28 to first end 22 may be by any convenient means including welding or a threaded interface between the two components. Cutter 28 is configured to drill through pavement 32 and produce a borehole 30 passing through the surface of pavement 32. The configuration of cutter 28 depicted is merely exemplary as other configurations may be used. In general, rotation of sign dart 10 by any convenient device while applying sufficient downforce will enable the formation of a borehole 30 by cutter 28. Therefore, cutter 28 will have sufficient hardness to produce the desired borehole through pavement 32. Typically, cutter 28 will be hardened steel and may include a titanium carbide bit. Cutter 28 has a cutting diameter which corresponds to or is slightly larger than the external diameter of shaft 12. Typically, the diameter of cutter 28 will be about 1% to about 2.5% larger than the diameter of shaft 12. In most instances, the diameter of cutter 28 will be about 1.5% to about 2.2% larger than the diameter of shaft 12. Generally, the diameter of cutter 28 will be about 1.8% larger than the diameter of shaft 12. For example, if hollow shaft 12 has an exterior diameter of 3.5 inches, then a typical diameter for cutter 28 will be 0.0625 inch ( 1 / 16 inch) greater than the exterior diameter of hollow shaft 12. Thus, the diameter of cutter 28 will be about 3.5625 inches. In some embodiments, cutter 28 will erode away during the drilling process such that cutter 28 has an outer diameter consistent with the diameter of hollow shaft 12. Cutter 28 may optionally include a passageway 29. Passageway 29 allows cuttings produced during formation of borehole 30 to pass into the interior 20 of hollow shaft 12.

[0019] Second end 24 of hollow shaft 12 carries a plate 34. Plate 34 has a central opening 36 aligned with the interior of hollow shaft 12. Plate 34 is configured to be engaged by driver 60 to permit drilling of a borehole through the pavement. The example driver 60 depicted in FIGS. 6A-6C is configured to engage plate 34; however, other configurations are also contemplated. Plate 34 is configured for use with both drop-in sign posts, FIG. 4, as well as with a multi-directional slip base breakaway system 40 as depicted in FIGS. 5A and 5B. Thus, plate 34 will have a generally triangle configuration with slots 42 at each point of the triangle. As depicted in FIGS. 5A and 5B, the sign post support portion of a conventional slip base breakaway system carries a corresponding upper plate 44 with corresponding slots 42. Joinder of lower base plate 34 to upper plate 44 is typically achieved using nuts 54, bolts 56 and shims 58 as necessary. Multi-directional slip base breakaway system 40 also includes an upwardly projecting sign post 46 suitable for supporting a sign 50. To accommodate drop-in sign posts, central opening 36 will generally be configured to receive a conventional sign post 46. As such, central opening 36 will in most instances have a length and width of about 2.625 inches. However, the size of plate 34 and central opening 36 may vary depending on the application of sign dart 10.

[0020] As depicted in FIG. 1, hollow shaft 12 is free of outwardly projecting elements between first end 22 and second end 24. As previously noted, cutter 28 has a diameter which corresponds to or is slightly greater than the external diameter of shaft 12. Thus, the resulting borehole will have a diameter which generally corresponds to or is slightly greater than the external diameter of shaft 12. As a result, shaft 12 will be in frictional engagement with the internal diameter of the resulting borehole. This frictional engagement is sufficient to support sign dart 10 and any subsequently attached sign posts or multi-directional slip based breakaway systems 40 in a stable, fixed manner. Thus, sign dart 10 does not rely upon threads, flanges or other outwardly projecting elements to provide for formation of the borehole or retention of sign dart 10 after installation.

[0021] Since the exterior of shaft 12 is free of external protrusions, threads, fins or other devices, retention of sign dart 10 results only from frictional engagement of hollow shaft 12 with the surrounding pavement. To be clear, retention of sign dart 10 in place does not require the use of binder material such as cement, asphalt or other affixing material. If shaft 12 penetrates beyond pavement layer 32, then frictional engagement of shaft 12 with the subsurface soil 33 provides sufficient frictional engagement to stabilize and retain sign dart in place. As a further benefit of the frictional engagement and retention of sign dart 10, and any subsequently supported multi-directional slip base breakaway system 40 or other sign post, sign dart 12 eliminates the need to add cement or other binder material to the hole in which sign dart 12 is secured. Thus, retention of sign dart 10 within pavement 32 and subsurface soil 33 relies solely upon frictional engagement between sign dart 10 and pavement 32 and subsurface soil 33.

[0022] With continued reference to the FIGS., improved sign dart 10 also provides an improved method of installation. The method of installing sign dart 10 does not utilize cement or other binding agents to retain sign dart 10 in the pavement or the subsurface soil below the pavement.

[0023] A rotational drive mechanism, not shown, rotates driver 60 which engages or is attached to plate 34. Any convenient rotational drive mechanism, e.g. a hydraulic driver, suitable for applying rotational force will suffice in this operation. As depicted in FIGS. 6A, 6B and 6C, driver 60 includes three side beams 62. Each side beam 62 has a notch 64 at a first end and a pivotal arm 66 carried at the second end of beam 62. Driver 60 also includes a top plate 68 and an attachment point 70 which may be engaged by any suitable rotation drive mechanism. As can be seen in FIG. 6A, driver 60 is configured to mate to the triangular configuration of lower base plate 34 carried by shaft 12. Further, driver 60 has notches 72 which corresponds to notches 42 of base plate 34. Thus, driver 60 may be temporarily joined to base plate 34 using nuts 54 and bolts 58 or the operator may rely solely on the interaction of side beams 62 and pivot arms 66 with base plate 34 during drilling operations. In the event that base plate 34 is square instead of triangular, then driver 60 will have one additional beam 62 and pivotal arm 66 but will otherwise work in the same manner as described above.

[0024] Operation of the rotational drive mechanism with driver installed on base plate 34 rotates sign dart 10 and applies downward force to sign dart 10 such that cutter 28 begins cutting through pavement 32 thereby forming borehole 30. Alternatively, the operator of the drive mechanism initiates rotation of driver 60 to begin the drilling operation and the operator applies downward force such that cutter 28 begins cutting through pavement 32 to form borehole 30. During drilling, cuttings formed by cutter 28 passing through pavement 32 and subsurface soil 33 may pass through passageway 29 into the interior of hollow shaft 12 or to the exterior of hollow shaft 12. To the extent that cuttings pass to the exterior of hollow shaft 12, those cuttings further enhance the frictional engagement of hollow shaft 12 with the interior of borehole 30.

[0025] Driving of sign dart 10 into and through the pavement 32 continues until plate 34 is within about 3 inches of the upper surface of the pavement 32 with openings 18 and 26 being above ground level. Thus, if pavement 32 does not extend the full length of shaft 12 and cutter 28, cutter 28 also forms borehole 30 in the subsurface soil 33. At this point, hollow shaft 12 is in contact with the interior of the resulting borehole 30 in pavement 32 and if present the subsurface soil 33. Following positioning of sign dart 10 in borehole 30, driver 60 may be removed and either type of sign post positioned within or secured to sign dart 10.

[0026] Because cutter 28 has a cutting diameter which is equal to or slightly larger than the exterior diameter of hollow shaft 12, the resulting interface between borehole 30 and exterior surface 14 of shaft 12 produces sufficient frictional engagement to retain sign dart 10 within the borehole 30 in a stable manner. The frictional engagement is sufficient to also support the subsequent attachment of sign post 46 with sign 50 as part of a multi-directional slip base breakaway system 40. Alternatively, a simple drop-in post 46 may be positioned within opening 32 and the interior of hollow shaft 12. When using a drop-in post 40, retaining bolt 52, will normally be positioned through opposing holes 18 and a corresponding hole(s) in drop-in post 46 as well as opposing holes 26 and corresponding hole(s) in drop-in-post 46 thereby retaining drop-in post 46 within hollow shaft 12. As noted above, bushings 27 will commonly be placed within holes 18 and 26 prior to placement of bolts 52. Retention of a multi-directional slip base breakaway system 40 to plate 34 and sign dart 10 will be achieved using nuts, bolts and shims as required to joint upper plate 44 to base plate 34 thereby providing the desired break-away system characteristics. In the break-away system 40, upper plate 44 supports post 46.

[0027] Thus, the described method for installing sign dart 10 does not require the use of a separate boring system to prepare a borehole for installation of sign dart 10 at the signage location. Further, formation of the borehole and positioning of sign dart 10 within the borehole occurs simultaneously. The simultaneous formation of the borehole and positioning of sign dart 10 generates a frictional engagement between the pavement and / or subsurface soil and hollow shaft 12 sufficient to retain sign dart 10 within 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 dart 10 within the borehole is not required. Thus, the method of installing sign dart 10 eliminates two steps currently required when installing roadside signage. Specifically, the described method does not require an initial borehole to receive sign dart 10 and does not utilize cement or other binding agent to retain sign dart 10 in the borehole.

[0028] 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.

Claims

1. A sign support system comprising:a sign dart having a hollow shaft, the hollow shaft having an exterior, an interior, a first end and a second end;the first end of the hollow shaft carries a cutter, the cutter configured to cut a borehole through a pavement material, wherein the cutter is configured to produce the borehole; and,the second end of the shaft carrying a plate, the plate having a central passageway in alignment with the interior of the hollow shaft.

2. The sign support system of claim 1, wherein the plate is configured as a base mounting plate of a multi-directional slip base breakaway system.

3. The sign support system of claim 1, wherein the cutter has a central hollow passage configured to direct cuttings to the interior of the hollow shaft.

4. The sign support system of claim 1, wherein the cutter is configured to form a borehole having a diameter which frictionally engages the exterior of the hollow shaft.

5. The sign support system of claim 1, wherein between the first end of the hollow shaft and the second end of the hollow shaft, the exterior of the hollow shaft is free of outwardly projecting elements.

6. The sign support system of claim 1, further comprising a driver configured to be removably secured to the sign dart.

7. The sign support system of claim 1, further comprising a driver configured to be removably secured to the plate carried by the second end of the shaft.

8. The sign support system of claim 1, wherein the sign support system does not include binder material.

9. A method of positioning a sign dart within a pavement material, the method comprising:providing a sign dart, the sign dart comprising:a hollow shaft having an exterior and an interior and a first end and a second end;the first end of the shaft carrying a cutter, the cutter configured to bore a hole through the pavement material; and,the second end of the shaft carrying a mounting plate;attaching a driver to the sign dart;cutting a borehole though at least a portion of the pavement material by using the driver to rotate the sign dart at a rate sufficient to permit the cutter to cut a borehole;continue cutting the borehole until the mounting plate is positioned a desired location from the pavement material;retaining the sign dart within the resulting borehole wherein the resulting borehole has a borehole wall which frictionally engages the hollow shaft.

10. The method of claim 9, wherein the driver is removably attached to the mounting plate.

11. The method of claim 9, wherein the exterior of the hollow shaft is free of outward projecting elements.

12. The method of claim 9, wherein the mounting plate has a central passageway in alignment with the interior of the hollow shaft; and, further comprising the step of using the central passageway to direct cuttings to the interior of the hollow shaft.

13. The method of claim 9, further comprising the step of removing the driver after retaining the sign dart within the resulting borehole.

14. The method of claim 9, wherein the resulting borehole is sized to frictionally engage the exterior of the hollow shaft and wherein the step of retaining the sign dart within the borehole relies upon the frictional engagement of the exterior of the shaft with the borehole15. The method of claim 9, wherein the resulting borehole is sized to frictionally engage the exterior of the hollow shaft and wherein the step of retaining the sign dart within the borehole does not require the use of binder material.

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