WO2007071065A1

WO2007071065A1 - Marker for cable buried within a hard or packed surface

Info

Publication number: WO2007071065A1
Application number: PCT/CA2006/002119
Authority: WO
Inventors: Darren Dofher
Original assignee: Teraspan Networks Inc.
Priority date: 2005-12-22
Filing date: 2006-12-22
Publication date: 2007-06-28

Abstract

A marker is provided for indicating the presence of a buried fibre optic or other cable. The marker includes a marker body having a flat upper surface suitable for flush-mounting within a settable material, such as concrete, asphalt, or joint filler, which has a generally plastic or flowable phase during which it may flow around a portion of the marker, and which subsequently sets, hardens or is packed so as to grip the marker and prevent its removal. The body is preferably elongate to fit within a narrow cut; for example if may comprise an elongate rectangular plate, although it may take on any suitable shape. Prongs or fins extend downwardly from the body to engage the material after to hardens or is packed.

Description

TITLE OF THE INVENTION

MARKER FOR CABLE BURIED WITHIN A HARD OR PACKED SURFACE

FIELD OF THE INVENTION

[0001] The present application claims the benefit of United States Patent application no. 60/753,203 filed December 22, 2005.

[0002] The invention relates to cable installations within hard surfaces such as pavement and specifically cable buried within joints between hard surfaces such as a road and sidewalk curb, and more specifically to markers for indicating the presence of such cables.

BACKGROUND OF THE INVENTION

[0003] Cable installations within urban areas, and specifically fibre optic communications cables, may be installed within narrow trenches cut into hard surfaces such as sidewalks, road surfaces, and the joints between sidewalks and roads. An example of such a system is described in the present inventor's published United States patent application no. 20050031287, which describes methods and apparatus for installing a network of cables within a hard surface such as roads, sidewalks, etc. Typically, such cables are set into the surface within a narrow trench or cut at a relatively shallow depth, often in the range of several inches. The surface is then typically restored, for example by filling with concrete, asphalt, or a joint sealant. It is important to be able to warn the public of the presence of buried cables, for example to avoid damage during future road maintenance, and also to permit easy location of the cables for maintenance of the cables themselves. For this purpose, it is desirable to provide a marker that is readily visible from the surface, but which at the same time is flush or nearly so in order to prevent damage. Such a marker should also be easy to install during the cable-laying operation, but also securely fastened in place once installed. Further, in the context of a typical in-joint installation the cut is typically quite narrow and thus the marker must also have a narrow side-side width in order to fit easily within the joint. [0004] Markers and indicating devices for installation within a settable material such as concrete have been disclosed. For example in U.S. Patent 6,425,212 to Lovanzzano, which discloses a marker for setting into concrete. The marker comprises flat plat with downwardly-extending retainers that become fixedly incorporated within the concrete when set. The retainers include horizontally-protruding feet for engaging the concrete slab. A generally similar marking device was disclosed in U.S. Patent 2,166,669 to Farrell, although for the intended use of installation on an asphalt road surface, in which case installation is carried out on an existing road surface.

[0005] Markers of this nature are also useful for use with packed material such as coldpatch asphalt or packed crushed stone such as crushed limestone. In this patent specification, the term "hard surface" includes packed loose material of this nature.

SUMMARY OF THE INVENTION

[0006] The present invention has as an object the provision of an improved cable marker suitable for use in installing within a soft settable material, such as a joint filler used to fill a road or sidewalk joint, for indicating the presence of a buried cable.

[0007] In one aspect, the invention comprises a marker for indicating the presence of a buried fibre optic or other cable. The marker includes a marker body which may be elongate, having a flat upper surface suitable for flush- mounting within a settable material, such as concrete, asphalt, or joint filler. The material may also comprise a packable material such coldpatch asphalt or crushed stone. The body defines a front-to back axis; preferably the body is elongate, such as rectangular, although the precise shape is not significant. The material is generally plastic or flowable in nature in one phase, such as concrete or asphalt which has a soft and flowable phase, or uncompacted loose material, in order to flow around a portion of the marker while in the flowable phase, and which subsequently sets, hardens or is packed so as to grip the marker and prevent its removal. The exposed upper surface of the body may be marked with suitable language such as "cable in joint" to indicate the presence of the buried cable. Preferably, the warning indication is engraved within the upper surface of the body. The body is preferably elongate to fit within a narrow cut; for example if may comprise an elongate rectangular plate, although it may take on any suitable shape.

[0008] The marker is retained within the settable surface by one or more downwardly-depending members such as prongs that engage with the surface material, if installed while the surface material is still in a flowable state. The retainer member or members are shaped or oriented to engage the soft material such that when the material hardens the retainer members are fixed in position without the use of glue or cement. This is achieved by shaping or orienting the member such that the flowable material may flow over a portion of the retainer member. When hardened, the material which overlies the retainer member fixes it in position.

[0009] For example, if the members comprise prongs, these may include fore and aft prongs that join with the marker body at or adjacent to the forward and rearward ends of the body, and protrude outwardly away from the body in the fore and aft direction. However, the prongs are vertical in the side-to-side direction for installation within a narrow cut. The forward prongs preferably extend downwardly and forwardly at about a 45 degree angle and the rearward prongs are a mirror image extending downwardly and rearwardly at the same angle, such that when viewed from the side the marker, including the prongs, tapers outwardly and downwardly to form a shape resembling a truncated triangle. The outward projection of the prongs permits the flowable or loose material to flow over and overlie at least a portion of the prongs. These prongs may terminate at their downward ends in generally horizontal outwardly- protruding feet for additional engagement with the settable material. Preferably, opposing pairs of such prongs are provided, comprising paired and parallel spaced apart plate-like members having vertical exterior sidewalls. Optionally, a further pair of opposed and paired prongs may be provided at about the midpoint of the marker between the fore and aft prongs to provide additional lateral stability. The marker plate is generally elongate and substantially rectangular, having opposing narrow ends and broad opposing sides. The width of the marker plate approximates the width of the typical cut for cable installation, and is elongate in order to indicate visually the width of the cable cut and its orientation.

[0010] In another aspect the invention comprises a method for marking the presence of a cable buried within a hard surface such as a paved roadway or sidewalk, comprising the steps of providing a cable installed within a cut within the paved surface, the cut defined by spaced apart sidewalls, and providing a marker as defined above. The marker and cut are sized such that the marker when positioned within the cut does not contact the sidewalls of the cut but permits sufficient clearance to permit fill material to flow between the marker prongs and the sidewalls of the cut. The cut is filled or substantially filled with a settable material such as hot asphalt tar, and the marker pressed into the material while still soft such that the upper surface of the marker is generally flush with the material, which is then permitted to harden. The clearance between the marker prongs and sidewall permits sufficient settable material to flow into this space to minimize any interference with the adhesion of the material to the sidewalls of the cut.

[0011] It is a further aspect to provide a marker that has minimal inhibition of the structure or strength of the settable material. This is accomplished by limiting the size of the prongs, or alternatively providing openings within the prongs to permit the settable material to permeate the prongs. The openings may comprise a mesh structure or alternatively other arrays of apertures.

[0012] In another aspect, the prongs are replaced by one or more downwardly-depending fins that extend vertically downwardly from the upper plate. The fin or fins are perforated to permit the settable material to engage the marker and prevent removal after the settable material has hardened. The perforations are sufficiently large to permit the plastic material to flow through them when the device is pressed into position, such that the material penetrates the fin through the perforations, thereby overlying a portion of the fin (namely within the interior of the perforations) to engage the device when the material sets. The perforations may extend fully or partway through the fin so as to permit the plastic material to at least partly penetrate the fin

[0013] In a more general aspect, the invention relates to a marker for indicating the presence of an object buried within a settable or packable surface, for engaging a plastic settable or a loose packable material without the use of cement, said material comprising a first plastic state and a second hardened or packed state, said marker comprising an body having a generally flat upper surface and defining a front to rear axis, front and rear ends and lateral sides, and at least one member extending downwardly from said body to engage said settable or packable material comprising a shape suitable for permitting said material to flow around and overlie at least a portion of said member to engage said member when hardened or packed.

[0014] Preferably, the marker includes a plurality of prongs extending downwardly from said plate, the prongs including at least one first prong extending downwardly and forwardly from the front end of the plate and at least one second prong opposed to said first prong extending downwardly and rearwardly from the rearward end of said plate, said first and second prongs extending axially parallel to said front to rear axis and not extending laterally substantially beyond the sides of said plate. Preferably, the first and second prongs each terminate at their lower ends in a generally horizontal foot for engaging said plastic material and preventing removal therefrom when fully set or packed. The first and second prongs may comprise generally platelike members having flat sidewalls and an elongate shape when viewed in horizontal cross section, said sidewalls of said prongs aligned with said front to rear axis of said marker plate. The first and second prongs may each comprise a pair of opposed spaced apart members aligned with opposing sidewalls of said plate.

[0015] The upper surface of the marker may include a written or graphic sign to indicate the presence of said buried cable.

[0016] The marker may include at least one intermediate prong between said first and second prongs extending downwardly from said body. The prongs may include a downwardly-facing tapered ridge extending along the downwardly- exposed faces thereof to permit said marker to slice into said material.

[0017] In one aspect, the marker prong may comrpise at least one fin having a plurality of apertures extending therethrough having a diameter sufficiently large to permit said plastic material to flow therethrough so as to at least partly penetrate said fin. This may consist of a single fin extending substantially vertically and aligned with the front to rear axis of said body, for example extending generally along midline of said body. Alternatively, there may be provided a pair of opposing fins on either side of said body aligned with the lateral sides thereof. These fins may flare outwardly and downwardly.

[0018] According to another aspect, the invention relates to a method for installing a marker within a settable or packable surface without the use of a cement, for engaging a plastic settable material without the use of cement, said material comprising a first plastic state and a second hardened or packed state, to indicate the presence of an object buried beneath said marker. The method includes the steps of:

- providing an elongate cut or groove within said material and installing a cable or other member into said cut, said cut defined by spaced apart sidewalls;

- filling said cut with a soft plastic or loose packable material in said first state to restore said surface, said material having sufficient plasticity to flow around a portion of the marker while in said first state; - providing a marker as defined in any of claims 1-13, having suitable dimensions to leave a gap between said sidewalls and said member to permit said material to flow therebetween while in said first state;

- pressing said marker into said cut while said material is in said first state until said at least one member is fully buried within said material and said body is generally flush with said settable material, and permitting said material to harden into said second state. The settable material may be a joint filling compound.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIGURE 1 is a perspective view of a marker according to the present invention;

[0020] FIGURE 2 is a further perspective view of the embodiment of Figure

1;

[0021] FIGURE 3 is a further perspective view of the embodiment, shown in an inverted position;

[0022] FIGURE 4 is a side elevational view of the embodiment of Figure 1;

[0023] FIGURE 5 is a top plan view of the marker;

[0024] FIGURE 6 is a photograph showing segments of pavement and pavement joints with a marker according to the present invention installed therein;

[0025] Figure 7 is a perspective view of a further embodiment of the invention and [0026] Figure 8 is a perspective view of a still further embodiment of the invention.

DETAILED DESCRIPTION

[0027] Referring to figures 1-5, a cable marker comprising an embodiment of the present invention includes an elongate plate-like body 10, having in plan view a generally rectangular shape defined by broad opposing sides 12 and relatively narrow opposing ends 14. The elongate dimension of the body 10 defines an elongate axis. The upper surface of the body optionally includes a written or graphic message 16 that may be printed or engraved into the surface, with the example herein engraved with "cable in joint". When used with this message, the marker is intended for installation within a roadway joint, for example a joint between a roadway surface and a sidewalk curb.

[0028] Extending downwardly from the marker body is a plurality of prongs

20 for retaining the marker without the need for cement, within a settable hard surface such as concrete or asphalt or joint filling compound. The prongs comprise opposing pairs of fore and aft prongs 20(a) and 20(b) adjacent to the narrow ends of the marker body. It will be seen that depending on the application, one or more of the individual prongs or paired sets thereof may be dispensed with, for example the fore or aft prongs 20(1) or 20(b) may be omitted for economy or to provide a more easily removed temporary marker. However, the structure illustrated herein is preferable for most applications.

[0029] The prongs comprise plate-like members, each pair of prongs being opposed and parallel to each other, joining with the marker body at the side edges thereof. Each prong extends downwardly and outwardly in the fore or aft direction at approximately a 45 degree angle. The preferred range of angles is between 35 and 55 degrees. Each prong 20(a) and (b) terminates at its lower end in a generally horizontal foot region 24. The overall shape of the marker when viewed from the side is thus a truncated triangle, tapering inwardly and upwardly. This shape permits the marker to be fixedly engaged after the settable surface has fully set.

[0030] The length of the prongs, and accordingly their protrusion, may vary depending on the intended application. For example, for use in loose material such as crushed stone or coldpack asphalt, it may be desirable for the prongs to be somewhat longer than for use with concrete or conventional asphalt, in order to provide more surface area for gripping the marker within the material.

[0031] An additional pair of prongs 20(c) is provided at approximately the mid-point of the body. This third pair of prongs comprises opposing substantially flat prongs depending approximately straight downwardly, and comprising a pair of spaced apart plate-like members of a similar structure to the end prongs.

[0032] The exposed edges of the respective prongs 20, and in particular the downwardly-facing lower edges 26 as well as the exposed vertical or partly vertical edges 28 of the prongs, taper towards a point to make it easier to press the prongs into a soft surface.

[0033] It will be seen that the marker may comprise any suitable size or relative dimensions. However, without wishing to be tied to any particular size or relative dimensions, a suitable size is to provide a body about 60 mm long and 10-12 mm wide, when viewed in plan, with an overall length including prongs of about 85 mm. The overall height of the prongs from lower edge to marker body may be about 20-25 mm. It has been found that a device having these dimensions is well suited for providing a visible notification to the public, while still being small enough to easily fit in a typical roadway joint. This size also provides good retention qualities when installed within a settable roadway surface.

[0034] In general, the width of the marker is defined by the width of the desired cut within which the marker is to be installed, such that when within the cut, there is a gap between the sidewalls of the cut and the marker prongs sufficient to permit the joint filler material to flow reasonably freely. This permits the material to adhere to the sidewalls of the cut with minimal interference from the marker prongs.

[0035] In another embodiment, shown in Figure 7, the prongs are replaced by a central fin 50 extending vertically downwardly from the body 10. The fin 50 is generally centrally disposed and is parallel to the central elongate axis of the body 10. A plurality of apertures 52 extend through the fin, to permit the fin to engage a flowable or plastic settable material. This is accomplished by providing the apertures of a suitable size to permit the material to flow through the apertures after the marker has been pressed into the material while soft. When the material hardens, the portion of material that extends through the apertures firmly grips the marker.

[0036] A still further embodiment is shown in Figure 8. In this embodiment, the fins 50 of the embodiment shown in Figure 7 are replaced by paired fins 50 which depend downwardly from each lateral side of the marker. The fins 50 may flare out slightly, as seen in Figure 8. Each fin 50 includes multiple apertures 52, so as to engage the material within which the marker is installed. This embodiment has the added advantage that the additional fin provides improved retention.

[0037] A preferred material for the marker is a rigid plastic material such as acetal. It will be seen that any suitable rigid non-corroding material may be used, including stainless steel as well as other plastic materials. Preferably, the marker comprises a one-piece rigid molding comprising plastic or other suitable moldable material. Persons skilled in the art will recognize suitable materials for the marker; such material is preferably one which is rigid, non-brittle and strongly resists corrosion. [0038] In use, a cable such as a fibre optic cable (not shown) is installed within a narrow trench or cut 30, in a known fashion. Typically, the cut is in the range of several inches in depth, although there is no particular limit to the depth of the cut. After installation, the surface is restored with a soft settable substance such as concrete or joint filler 32. The substance is flowable while in a first phase, in that it is sufficiently plastic to flow around the retainer member, namely the prongs 20 or through the openings 52 of the retainer fin 50. In this manner, the substance comes to overlie a portion of the retainer, and when in its second phase the substance hardens or is compacted this overlying portion prevents removal of the marker without the need for glue or cement. The lower edge 54 of the fin 50 is tapered towards a knife edge to permit the fin to more easily be pressed into the plastic joint filler material. Preferably the body 10 and fin 50 are injection molded as a one-piece unit.

[0039] While the plastic joint filler material is still soft, at least one and preferably a plurality of markers are installed at regular intervals within the restored surface. Each marker is simply pressed into the surface 32 while still soft, to the point where the surface of the body is generally flush. Upon hardening of the settable material, the marker will be permanently installed, with the fore and aft prongs preventing removal thereof except by breaking up the settable material. Preferably, the graphic or written text on the surface of the marker is engraved, such that the text remains visible even when covered with a layer of grime or dirt. Preferably, the markers are installed such that their elongate axes substantially align with the buried cables, in order to provide a visual queue as to the location of the buried cables.

[0040] A similar installation process may be used to install the markers in loose packable material such as coldpack asphalt or crushed stone, the markers may be pressed into this material while the material is loose and unpacked, following which the material is packed and compressed so as to cause the material to flow around the marker prongs or fins and thereby retain the marker firmly within the packed surface. [0041] The invention has been described herein by way of detailed descriptions and illustrations which relate to various embodiments and features of the invention. However, persons skilled in the art to which this invention pertains will readily understand that the invention is not limited to any of the features and elements described or illustrated herein. Rather, the full scope of the invention is to be derived and understood from this patent specification as whole including the accompanying claims. I will be understood that elements set forth or described in this patent specification include their structural or functional equivalents. The skilled person will understand that one may depart from or vary the described or illustrated features while remaining within the scope of the invention.

Claims

CLAIMS:

1. A marker for indicating the presence of an object buried within a settable or packable surface, for engaging a material which in one phase is a plastic settable or a loose packable material, said marker being capable of being retained within said material without the use of cement, said material comprising a first plastic phase and a second hardened or packed phase, said marker comprising an body having a generally flat upper surface and defining a front to rear axis, front and rear ends and lateral sides, and at least one member extending downwardly from said body to engage said settable or packable material comprising a shape suitable for permitting said material to flow around and overlie at least a portion of said member to engage said member when hardened or packed.

2. A marker as defined in claim 1 wherein said member comprises a plurality of prongs extending downwardly from said plate, the prongs including at least one first prong extending downwardly and forwardly from the front end of the plate and at least one second prong opposed to said first prong extending downwardly and rearwardly from the rearward end of said plate, said first and second prongs extending axially parallel to said front to rear axis and not extending laterally substantially beyond the sides of said plate.

3. A marker as defined in claim 2 wherein said first and second prongs each terminate at their lower ends in a generally horizontal foot for engaging said plastic material and preventing removal therefrom when fully set or packed in said second phase.

4. A marker as defined in claim 2 wherein said first and second prongs comprise generally platelike members having flat sidewalls and an elongate shape when viewed in horizontal cross section, said sidewalls of said prongs aligned with said front to rear axis of said marker plate.

5. A marker as defined in claim 4 wherein said first and second prongs each comprise a pair of opposed spaced apart members aligned with opposing sidewalls of said plate.

6. A marker as defined in claim 1 for indicating the presence of a cable buried within a cut within said material, said upper surface of said marker including a written or graphic sign to indicate the presence of said buried cable.

7. A marker as defined in claim 2 further comprising at least one intermediate prong between said first and second prongs extending downwardly from said body.

8. A marker as defined in claim 2 wherein said prongs each include a downwardly-facing tapered ridge extending along the downwardly-exposed faces thereof to permit said marker to slice into said material.

9. A marker as defined in claim 1 wherein said member comprises at least one fin having a plurality of apertures extending therethrough having a diameter sufficiently large to permit said plastic material to flow therethrough so as to at least partly penetrate said fin.

10. A marker as defined in claim 9 comprising only a single fin extending substantially vertically and aligned with the front to rear axis of said body.

11. A marker as defined in claim 10 wherein said fin extends from generally the midline of said body.

12. A marker as defined in claim 9 comprising a pair of opposing fins on either side of said body aligned with the lateral sides thereof.

13. A marker as defined in claim 12 wherein said fins flare outwardly and downwardly.

14. A method for installing a marker within a settable or packable surface without the use of a cement, for engaging a plastic settable material without the use of cement, said material comprising a first plastic state and a second hardened or packed state, to indicate the presence of an object buried beneath said marker, comprising the steps of:

- filling said cut with a soft plastic or loose packable material in said first state to restore said surface, said material having sufficient plasticity to flow around a portion of the marker while in said first state;

- providing a marker as defined in any of claims 1-13, having suitable dimensions to leave a gap between said sidewalls and said member to permit said material to flow therebetween while in said first state;

- pressing said marker into said cut while said material is in said first state until said at least one member is fully buried within said material and said body is generally flush with said settable material, and permitting said material to harden into said second state.

15. A method as defined in claim 14 wherein said settable material is a joint filling compound.

16. A method as defined in claim 14 wherein said cut is located within a preexisting joint within a sidewalk, roadway or joint between a sidewalk or roadway.

17. A method as defined in claim 14 wherein said material comprises a packable material, and said material is hardened by packing said material.