CA2844591A1

CA2844591A1 - System for strengthening poles

Info

Publication number: CA2844591A1
Application number: CA2844591A
Authority: CA
Inventors: Martin STANLEY; Glenn ALLSOP
Original assignee: Babcock Networks Ltd
Current assignee: POLE STRENGTHENING SYSTEMS Ltd
Priority date: 2011-08-16
Filing date: 2012-08-15
Publication date: 2013-02-21
Also published as: WO2013024292A2; GB201114097D0; BR112014003439A2; GB2509846A; EP2744956A2; US20140346308A1; ZA201401111B; GB201404473D0; WO2013024292A3; GB2509846B

Abstract

Disclosed is a system for strengthening a pole (100) comprising a support element (102) for supporting the pole; and fastening means (104,106) for securing the support element to the pole; wherein the fastening means comprises a pair of mutually engaging fastening parts, including a bolt part (104) and a corresponding nut part (106) adapted to engage with the bolt part; and wherein the support element comprises an aperture (408) adapted to receive a first one of the pair of fastening parts, and wherein at least one of the aperture and the first fastening part is shaped to prevent rotation of the first fastening part when located in the aperture.

Description

2 System for Strengthening Poles Background of the Invention For wooden utility poles the most common mode of failure is the degradation of the timber at ground level. For example, course grained wood in soft ground is particularly susceptible to weakening over the course of time. Deterioration is promoted by the environmental conditions of the pole. Typically, the region approximately 200 mm above and below the ground level decays, eventually to the point where the pole is structurally unsound. The rest of the timber pole typically suffers far less damage and can still be structurally sound when the ground level is already significantly damaged.
The service life of deteriorated wooden poles can be extended by strengthening the poles at ground level. By strengthening existing deteriorated poles, the replacement of poles can be delayed. Extending the service life of poles as opposed to simply replacing them is preferable as it is cheaper and minimises interruptions to the utility supply.
One conventional solution to the problem of ground level deterioration of wooden utility poles is to wrap a support around the base of poles. This type of solution only provides little lateral support. Further, the wrap obstructs access to the pole for inspection, and also tends to create unfavourable local conditions that encourage further deterioration. Another conventional solution to the problem is to fasten a supporting pin to the pole. A good connection can be achieved by drilling and reaming a large hole through the pole, then bolting the pin to the pole.
This solution however weakens the pole. Misalignment is also common in existing solutions, leading to poles not being sufficiently supported.
To counteract the adverse effects of ground level deterioration, a solution is required that can safely reinforce damaged poles.
Another problem encountered when strengthening poles is that the pole supports are exposed to tampering or theft. Therefore, a solution which improves the security of the pole strengthening system is required.
The present invention seeks to alleviate at least some of the above problems.
Statement of Invention The present invention relates to a system for supporting a pole. According to one aspect of the present invention, the system comprises a support element for supporting the pole; and fastening means for securing the support element to the pole; wherein the fastening means comprises a pair of mutually engaging fastening parts, preferably including a bolt part and a corresponding nut part adapted to engage with the bolt part; and wherein the support element comprises an aperture adapted to receive a first one of the pair of fastening parts, and wherein at least one of the aperture and the first fastening part is shaped to prevent rotation of the first fastening part when located in the aperture.
By preventing rotation of the first fastening part (which may be the bolt part or the nut part), installation can be simplified and subsequent tampering made more difficult. Other types of fastening means and fastening parts may be used instead of a nut and bolt.
Preferably, the aperture is shaped to prevent rotation of the first fastening part when located in the aperture.
The first fastening part may comprise a shaped portion having a shape corresponding to the shape of the aperture so as to prevent rotation of the first fastening part when the shaped portion is located in the aperture.
Preferably, the first fastening part is the bolt part.
The bolt part may comprise a head and a shaped portion shaped to prevent rotation of the bolt part, the shaped portion being proximal or adjacent to the head.

3 The bolt part may be arranged, when fully inserted through the aperture, so that the head abuts a surface of the support element around the aperture and the shaped part of the bolt engages the aperture having a corresponding shape to thereby prevent rotation of the bolt. Thus, when fully inserted the bolt will preferably be held in place by the aperture.
The aperture and/or a portion of the first fastening part may have a non-circular shape, preferably a rectangular or square shape. Other non-circular shapes (e.g.
hexagonal) could be used. Alternatively the shape could be substantially circular (or another shape) but with formations (e.g. complementary notches/protrusions) serving to prevent rotation (and thus lock the first fastening part into place).
The second fastening part may be arranged for engagement with a fastening tool to enable rotation of the second fastening part. The fastening tool is preferably a non-standard fastening tool as described in more detail below.
The second fastening part may comprise a head having one or more apertures for engaging complementary formations on the fastening tool.
The system may further comprise one or more nails for insertion through the one or more apertures in the head of the second fastening part. This can allow the nails to be driven into the pole to secure the second fastening part against the pole and thereby prevent subsequent rotation or slippage of the second fastening part.
The nails may be headless nails, also referred to herein as security nails.
This can make tampering with the nails and the second fastening part more difficult.
The second fastening part is preferably the nut part.
For added security, the nut part may be arranged to be recessed at least partially, optionally mostly or substantially fully, into the pole.
The support element may comprise at least one (preferably elongate) support surface arranged to be placed against a surface of the pole to provide support to

4 the pole. The support surface is preferably curved, preferably with a curvature corresponding to that of the pole surface.
The aperture may be located in (extend through) the support surface.
The support element may comprise a plurality of apertures for use with a plurality of respective fastening means. This can improve the strength and durability of the system.
The system may comprise a plurality of support elements for fastening to the pole.
According to another aspect of the present invention there is provided a support element for supporting a pole, preferably for use in a system as described above, the support element comprising: at least one (preferably curved) support surface adapted to be placed in contact with the surface of the pole to thereby support the pole; and at least one aperture adapted to receive a bolt for securing the support element to the pole, the aperture being shaped to prevent rotation of the bolt when the bolt is inserted through the aperture.
The aperture may be shaped to allow the bolt to pass through the aperture and to engage a correspondingly shaped portion of the bolt such that rotation of the bolt is prevented.
The aperture may be non-circular, preferably rectangular or square.
The support element may further comprise a pair of apertures positioned so as to receive a pair of bolts which are angled relative to one another in a plane perpendicular to the (radial) axis of the pole.
The apertures may be arranged to give an angle between the bolts, when installed, of between 70 and 110 , preferably between 80 and 100 , more preferably substantially 90 . This can improve the strength and rigidity of the system.

The support element may have at least one ridge or rib lengthwise.
The support element may comprise two curved flanges arranged for placement against the surface of the pole, the curved flanges separated by a ridge extending

5 along the longitudinal length of the support element.
One or both of the flanges may be tapered to assist in insertion into the ground.
According to another aspect of the present invention there is provided a bolt for use in securing a support element to a pole, preferably for use in the system described above, the bolt comprising a head and a shaft, the shaft including a shaped section, the shaped section shaped so as to prevent rotation of the bolt when the bolt is located in a correspondingly shaped aperture of the support element. Preferably, the rest of the bolt shaft (the part of the bolt shaft not including the shaped section) has a circular cross section.
The bolt head may be arranged to substantially prevent manipulation by a fastening/unfastening tool.
The bolt head preferably lacks formations suitable for engagement by a tool and/or may have a flat or dome-shaped, preferably substantially smooth, surface.
The shaft may have a length of between 95% and 98% of the pole diameter, preferably substantially 97% of the pole diameter.
According to another aspect of the present invention there is provided a nut for use in securing a support element to a pole, preferably for use in the system described above, wherein the nut has a head and a body with a threaded bore;
wherein the body is adapted to be recessed into the pole with the head protruding from the pole, and wherein the bore comprises a shoulder which is adapted to guide a bolt into the bore. This can assist with alignment of nut and bolt and so simplify installation.
The shoulder may be one of: chamfered; or rounded.

6 The nut head may have a form arranged to fit a non-standard tightening tool.
Use of a non-standard tightening tool may improve security by preventing tampering.
The term "non-standard tightening tool" preferably refers to a tool specially adapted for use with the present system, for example by way of a tool part designed for engagement with the nut head by way of a specially adapted shape and/or specially adapted engagement formations corresponding to a shape and/or engagement formations of the nut head.
The nut head may comprise formations adapted to engage with complementary formations on a tightening tool, the formations comprising at least one of:
one or more grooves; one or more recesses; one or more apertures; or one or more protrusions.
The diameter of the nut body may be between 130% and 180% of the bore diameter, preferably between 140% and 170%, more preferably between 150%
and 160%, or around 155%.
The diameter of the nut head may be between 180% and 380% of the bore diameter, preferably between 220% and 340%, more preferably between 260%
and 300%, or around 280%.
The diameter of the nut head is preferably at least 120% of the nut body diameter, or at least 130%, or at least 150%.
The nut head may have one or more apertures adapted to receive one or more nails which can be inserted through the apertures into the pole.
One or more of the apertures for receiving nails may also be arranged to engage with corresponding formations on a tightening tool. This can simplify the design of the nut head.
According to another aspect of the present invention there is provided a method for reinforcing a pole, the method comprising: placing an elongate support element adjacent to said pole; boring at least one bore hole through said pole; for each bore hole, boring a recess adapted to receive a respective nut; inserting

7 through the support element and through each said at least one bore hole a respective bolt; inserting in each at least one recess a respective nut; and fastening each bolt to a respective nut. Recessing the nuts in this way can prevent tampering. The nuts are preferably partially or mostly recessed, preferably with only a nut head extending out of (and lying against a surface of) the pole as described elsewhere herein. The nut head is preferably substantially flat, and may for example be in the form of a disc, which may allow it to lie flush against the pole surface.
The two bore holes may be angled to one-another in the radial plane of the pole and adapted to receive a bolt each.
At least a portion of said bore hole and said recess may be bored in a single step, preferably using a single tool and/or a single drill bit.
In a further aspect of the invention, there is provided a boring or drilling tool having a drill bit, and/or a drill bit, preferably for use in or with a method or system as described above, comprising a first section (preferably a tip of the drill bit, preferably for drilling a bore through a pole to receive a bolt) and a second section (preferably for drilling a recess for a nut) wherein the first section has a first diameter, preferably corresponding substantially to the diameter of the bolt, and the second section has a second diameter larger than the first diameter, the second diameter preferably corresponding to the diameter of the body of the nut (or other part of the nut which is to be recessed into the pole).
The first diameter may be between 12mm and 20mm, preferably between 14mm and 18mm, for example around 16mm. The second diameter may be between 21mm and 29mm, preferably between 23mm and 27mm, for example around 25mm.
The second diameter may be between 130% and 180% of the first diameter, preferably between 140% and 170%, more preferably between 150% and 160%, or around 155%.
The depth of the recess preferably corresponds to the size of the nut which is to

8 be recessed, for example, between 48mm and 64mm, preferably between 52mm and 60mm, or around 56mm. The depth may be between 300% and 400% of the first diameter, preferably between 325% and 375% of the first diameter, for example around 350% of the first diameter. The depth may be between 175%
and 275% of the second diameter, preferably between 200% and 250% of the second diameter, for example around 225% of the second diameter.
The dimensions (e.g. diameters and lengths) of the sections of the drill bit preferably correspond to the dimensions of the bolt/bore hole and nut/recess as described elsewhere herein.
The transition from first to second section may be gradual (e.g. sloped) or may comprise one or more step changes. The length of the first section may be arranged to allow a complete bore hole to be drilled through the pole, for example at least 248mm, so that the total length of the drill bit is greater than the diameter of the pole (thereby allowing a nut recess and bore hole to be drilled in one action), or may be shorter; in which case the drill bit may be arranged to drill a recess for a nut (using the second, wider section) and at the same time create a guide hole (using the first, narrower section) for subsequent boring of the main bore hole in a second step, using a different tool/drill bit. This can make it easer to ensure a good alignment between nut recess and main bore hole.
The tool / drill bit may be used in a method as set out above. In a further aspect of the invention, there is provided a method of preparing a pole (and/or boring one or more nut recesses and bore holes) using a drill bit as set out above.
The system and its elements set out above and described in more detail below are preferably adapted for use with poles having a substantially circular cross section. However, the system may alternatively be used with poles having non-circular (e.g. square) cross section. In that case, the support element need not be curved or have curved flanges as described. Instead the support element (and/or the described flanges) may instead be substantially flat, or may have any other suitable shape or configuration (e.g. U-shaped), preferably selected to enable the support element to be placed against, and provide support to, the surface of the pole.

9 The invention extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings.
Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure Any feature in one aspect of the invention may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa. Furthermore, any, some and/or all features in one aspect can be applied to any, some and/or all features in any other aspect, in any appropriate combination.
It should also be appreciated that particular combinations of the various features described and defined in any aspects of the invention can be implemented and/or supplied and/or used independently.
These and other aspects of the present invention will become apparent from the following exemplary embodiments that are described with reference to the following figures in which:
Figure 1 shows an overview of a pole strengthening system;
Figure 2 shows a cross section of a pole having been strengthened by the pole strengthening system of Figure 1;
Figure 3 shows the preparation of the pole of Figure 1 for strengthening;
Figures 4 show schematic views of the support element used in the pole strengthening system of Figure 1;
Figures 5 show schematic views of the nut and bolt used in the pole strengthening system of Figure 1;
Figures 6 show schematic views of the nut, tightening tool, washer, and security nails used in the pole strengthening system of Figure 1;
Figure 7 shows use of the tightening tool;
Figures 8 shows an example of a device adapted to install the pole strengthening system of Figure 1; and Figure 9 shows an example process diagram of the installation of the pole strengthening system of Figure 1.
Detailed Description of the Invention 5 Figure 1 shows a system for strengthening wooden poles 100 where a support element 102 is securely fastened to a pole 100 using a system of bolts 104.
The system may restore the pole to its former strength and enable the pole to withstand loading even when there is a total decay of wood at or below ground level.
The pole strengthening system (PSS) provides stability and extends the life of a pole without requiring any sound wood at ground level in order to be safe and effective. The system may potentially support a pole for as long as 20 years, or longer. Further, the system has sufficient strength to restore a pole without enclosing the deteriorated region. This advantageously permits natural drainage, and can also enable inspection, for example in order to monitor future pole deterioration. At the same time, the present system is designed to discourage or prevent tampering.
The system described herein is adapted to strengthen a wide variety of poles including substation poles, switch poles, small diameter poles, and other poles used in telephony networks, electrical networks, or other contexts. These poles may be wooden, or made from other materials. Replacing these poles can require de-energising of the network, which not only requires considerably more safety precautions, but can also lead to service outages. When repairing a pole using the method described herein, generally the pole can be reinstated without the need to have the conductors de-energised. The working height of the reinstatement equipment ensures that work can be safely performed whilst still maintaining the necessary safety distances from exposed conductors. This allows the overall costs associated with the reinstatement of poles to be minimised.
Although specific sizes and materials are described in relation to the drawings, it is clear that a range of different dimensions and materials are possible, corresponding to the situation in which the system is to be implemented.
Therefore, the user can select the most appropriate dimensions and materials for the particular application (for example, in the case of a standard telegraph pole, the dimensions and materials may be adapted based on the relevant pole loadings). The dimensions given below and in the figures relate to an example of a wooden pole of standard size (for example a utility pole such as a wooden telegraph pole) unless otherwise indicated.
It should also be noted that, though principally described in the context of wooden poles, the present approach may also be used with poles made from other materials (for example metal street lamp poles may be reinforced using this system with dimensions altered as necessary).
Figure 1 shows a pole 100 which is in need of strengthening. Poles 100 generally extend into the ground, and rot 101 (in the case of wooden poles) or other damage is common around ground level. The system might also be used, for example, to deal with impact damage or a leaning pole. The pole strengthening system described herein strengthens the section of the pole 100 around ground level. The pole strengthening system comprises a support element 102 and at least one bolt 104 with a corresponding nut 106. In one embodiment, the support element 102 is three metres long, formed from either 6mm or 8mm steel plate.
This size ensures adequate penetration into the ground and sufficient strength to provide support. The length of the support element 102 depends on the type of ground it is driven into and the amount of loading it is expected to support.
Further details relating to the support element 102 are described below in relation to Figure 4.
In use, the support element 102 is driven into the ground adjacent to the pole to a sufficient depth as to be able to support the loading from the pole without slippage. In one example, this is between 1.4 to 1.7m. The support element 102 is then attached to the pole 100 at a number of points by bolts 104 and nuts 106.
This solution can sufficiently strengthen poles, whilst permitting natural drainage and subsequent inspection. Installation is relatively straightforward and economical.

In the example of Figure 1, a single support element 102 is used. However, more than one support element may be used depending on loading and other requirements. Multiple support elements 102 can be used, but there may be a trade-off between stability provided and obstruction to natural drainage and inspection. In one example where the pole 100 has approximately 30% decay at ground level, adding a support element 102 as described herein restores the pole to 1.5 times its original strength (i.e. a supported, decayed pole can withstand 1.5 times the load of a non-supported, non-decayed pole).
Figure 2 shows a cross-sectional view of the pole 100 of Figure 1 after being strengthened. In this view, the cross-section through one bolt 104 is shown for clarity. Two or more bolts 104, at different pole cross-sections, different orientations, or different lateral positions, can be used, for example four bolts as illustrated in Figure 1. The bolts 104 are placed through pre-bored holes in the pole 100 and are secured in place by nuts 106. The nuts 106 are sized so as to recess into the pole 100 to a distance where the diameter of the bore hole changes (see below and Figure 3). The nut 106 is sized so as to receive the bolt 104 and has internal threading corresponding to the thread of the bolt 104.
The bolt 104 is screwed in, preferably by rotating the nut 106 using tightening tool 600 as described in more detail below. Advantageously, the bolts 102 are tightened to a torque of between 100 Nm and 150 Nm, preferably 130 Newton metres. This torque ensures that the load is adequately transferred to the support element without the bolt 104, nut 106 or support element 102 damaging the pole 100.
One advantage of the recessed nut 106 construction is that the finished pole 100 has no substantial protrusions.
Security nails 108 may be inserted through holes in the nut 106 and driven into the pole 100, thus securing the nut 106 and providing additional protection against tampering. A locking washer such as a star washer may be placed between the head of the bolt 104 and the pole 100 so as to prevent unscrewing of the bolt. The bolt head is shaped so that in cannot be gripped to be unscrewed, for example, by having a bevelled or smoothly rounded head. The bolt head is preferably smooth without recesses or other formations for engagement with screwdrivers, spanners, or other fastening tools, so as to prevent unfastening once installed. A plain washer may be placed between the head of the nut 106 and the pole 100 to distribute the pressure exerted by the nut 106 over a wider area of the pole 100.
Figure 3 shows the preparation of a pole 100 which is to be strengthened using the above described apparatus and method. A through hole for the bolt 300 is drilled with a drill 304. The bolt bore hole 300 has substantially the same diameter 308 as the bolt 104 (in this example 16mm). Preferably, the bore hole 300 is slightly larger than the bolt 104 to ensure that the bolt 104 can be inserted easily.
The bore hole 300 extends through the pole 100, ideally (but not necessarily) along the radial axis of the pole 100, passing through the centre of the pole 100.
The nut recess 302 at the opposing side of the pole 100 to that of the support element 102 is bored at a larger diameter 310 than the bolt bore hole 300.
Advantageously, the nut recess 302 and bolt bore hole 300 are drilled at the same time using a dedicated tool 304 which has tip 314 having a first diameter corresponding to the diameter of the bore hole 300. This tip advantageously has a length the same as or longer than the length of the bore hole 300. The tool then has a second section 316 with a diameter corresponding to the diameter of the recess 302. This second section 316 advantageously has a length the same as or longer than the depth of the recess 302. In an alternative embodiment, the bore hole 300 and the recess 302 are drilled separately.
In one example, the nut recess 302 has a diameter 310 of 25mm and a depth 306 of 56mm to receive the nut. These dimensions ensure, for a wooden pole, that the bolt 104 can be tightened sufficiently and that the minimum amount of material is bored out. Here also the diameter 310 and depth 306 may be slightly larger than the nut dimensions to ensure that the nut 106 fits properly. The construction thus advantageously consists of a bore hole 300 extending along a radial line through the centre of the pole 100. The bore has a step-change in diameter at a depth 306 corresponding to the length of the nut 106. The diameter of the bore hole 300 increases from substantially the diameter 308 of the bolt to the outer diameter 310 of the nut 106. It should be noted that for different poles, these dimensions may be different. In the case of a hollow metal pole, there may be no recess 302, rather a hole bored through the shell of the pole with a diameter of the outer diameter of the nut 512, but smaller than the diameter of the head of the nut 501 (Figure 5).
This construction affords the advantages of requiring a small amount of pole material bored out, as the only recess is sized to fit the nut only, hence not compromising the strength of the pole 100 unduly. There are also no exposed nuts, which reduces the chance of damage or tampering. This also improves the aesthetic properties of the pole 100 as a whole. The use of dedicated tool 304 also means that the nut 106 and bolt 104 automatically align and fit flush to the pole 100, as is described in more detail below.
Preferably, two bolts 104 (at slightly offset pole heights) are ideally positioned so that they are substantially orthogonal to each other. This ensures that the bolts 104 provide substantial support whichever direction the load on the pole 100 is orientated. In situations where orthogonal positioning of the bolts 104 is not practicable, the bolts 104 are positioned as close to orthogonal as is practicable.
This load is then transferred to the support element 102. To ensure that the bolts 104 are substantially orthogonal, the support element 102 ideally covers an angle of at least 90 of the pole 100.
Figure 4 shows the support element 102 used in the pole strengthening system described above and Figure 1. Figure 4 shows the profile of the support element 102; it is substantially formed of two curved flanges 410, with a particular radius of curvature arranged to match that of the pole which the support element is designed to fit around. Joining the two flanges 410, there is a rib 400 which has a rectangular cross-section. This is to improve the strength of the support element 102. In the- above example, the radius of curvature of the flanges is 152mm and the rib is 80mm wide. The support element 102 is uniform in width all the way along its length, in the above example; the support element is 194mm wide.
This affords a simple manufacturing process as, for example, many pins 102 can be stamped from a single sheet of metal with minimal wastage. The rib 400 tapers from a radial extent of 110mm at the top to 17mm at the bottom as is illustrated by the side view of Figure 4(a). This aids insertion into the ground. In a preferred example, the rib 400 is manufactured separately and is welded to the pin 102 to simplify the manufacturing process.

In another example illustrated in Figure 4(d), the support element 102-1 tapers 402 towards the end which enters the ground to further aid the insertion into the ground. In one embodiment, the taper 402 only affects the size of the two flanges in a symmetrical fashion, and not the width of the rib 400. In this example, the rib 5 extends radially 60mm from the support element 102 and 80mm laterally at the top of the support element 102. The rectangular rib 400 reduces in size also;
at the base of the support element 102, the rib 400 extends radially 24mm from the support member, and has the same lateral dimension (as shown in Figure 4(d)).
This taper 402 does not affect the radius of curvature of the support element 102.

10 It is designed so that the curved flanges of the support element 102 are in contact with the pole 100 along the entire length of the support element 102.
Alternative support element designs with more or fewer than one rib 406, different rib cross-section geometry 404 (e.g. as a curved or arched rib), and/or different dimensions may also be used.
As mentioned above, the support element 102 is attached to the pole 100 by the use of an individually tailored nut part 106 and optionally washers on the far side.
In this example the upper bolts are installed substantially 1.2m out of the ground.
The support element 102 includes apertures 408 for receiving the bolts 104.
The apertures 408 are preferably located as offset pairs. Specifically, the apertures 104 of each pair are offset to one-another along the axis of the pole 100, so that respective bolts can pass through the centre of the pole 100 without interfering with each other. In the above example, this offset is 100mm, and the uppermost pair of apertures 408 (on opposing flanges 410) are spaced 150mm and 250mm from the top of the support element 102 respectively. Apertures 408 of each pair are positioned on opposite flanges 400, so that the bolts 104 are substantially orthogonal to one-another. Pairs of bolts 104 are ideally positioned with one pair being located near ground level and the other near the top of the support element 102. In the above example, the pairs of apertures 408 on the same flange 408 are spaced 600mm from each other.
The apertures 408 are shaped so that they rotationally restrain a bolt 104.
This is achieved by the apertures 408 being non-circular, for example square, and the bolt 104 having a section 516 (see Figure 5) immediately next to the bolt head 502 with a corresponding shape. This provides the advantage of the bolt 104 being held stationary when the nut 106 is screwed on, as will be described in more detail below.
The bolt apertures 408 are shown to be square, but could be oval, hexagonal or any other non-circular shape which the bolt 104 could fit in, hold the bolt stationary and still bind the support element 102 to the pole 100.
Alternatively or preferably additionally, the non-circular shaped section of the bolt 516 (see Figure 5) may engage with the material of the pole which rotationally restrains the bolt 104. This may not be preferable in situations where the pole 100 is degraded as the bolt 104 may slip and cause damage to the pole 100.
Figure 5 shows the bolt 104 and nut 106 used in the pole strengthening system described above. The bolt 104 may for example be a coach bolt. In one embodiment up to eight bolts are used for a pole reinstatement. Four is a preferable number of bolts 104. Bolts 104 are preferably between 12mm and 20mm, more preferably between 14mm and 18mm, even more preferably, approximately 16mm in diameter, heavy galvanised, with a length to suit the pole diameter. In the example above where the radius of curvature of the flanges of the support element 102 is 152mm, the length of a bolt 104 is 295mm. This is so that the bolt 104 passes through the centre of the pole 100 and can engage with the recessed nut 106. The length of the bolt 104 is preferably between 90% and 99% of the pole diameter, more preferably between 95% and 98%, even more preferably 97%.
The bolt 104 has a head 502, a shaft 518 and a non-circular section 516 between the shaft 518 and the head 502. The non-circular section 516 is adapted to engage with the non-circular apertures 408 of the support element 102. This section 516 may be square, hexagonal or any other non-circular shape but should match the shape of the apertures. The shaft 518 comprises threaded and non-threaded sections.
The bolts 104 are inserted through the support element 102 and pole 100, and when tightened with the nut 106, they clamp the support element 102 to the pole 100, effectively binding the pole 100 and ensuring the integrity of the reinforced pole.
Unlike systems where both the nut and bolt can be rotated relative to each other by way of suitable tools (for example an operator may hold the bolt stationary by means of a tool during tightening whilst turning the nut with another tool or vice versa), in the present system only the nut can be rotated using an appropriate tool. This makes the system less susceptible to tampering. The bolt 104 as described above is held rotationally stationary by shaped apertures 408 (this also conveniently means that only one tool is required to tighten or loosen the nut). To further improve security, the bolt head can be shaped to prevent gripping and/or rotation by a tool. As an example, the bolt head may have a flat or dome-shaped, substantially smooth surface.
Furthermore, since the nut is recessed into the pole it is less accessible (e.g. to spanners, pliers or similar standard tools) and can preferably only be manipulated using a specially adapted tool, as described in more detail below.
The non-circular holes 408 in the support element 102, combined with the correspondingly shaped section 516 of the bolt 104 stop the bolt 104 rotating during tightening. Furthermore, the use of a lock washer 500 placed in between the bolt head 502 and the support element 102 further ensures that the bolt does not slip when tightening.
The nut 106 fits into the hole drilled and reamed into the exterior surface of the wooden pole 100. The size and shape of the nut 106 ensures that the support element 102 remains in contact with the pole 100 at all times, even if shrinkage of the timber occurs. The nut has a head 501 at one end and a bore 504 that is threaded 506 at the other end. The threaded end 506 of the nut is recessed into the pole 100. For example a typical length of the recessed part 508 of the nut is between 35mm and 80mm, preferably between 50mm and 60mm, more preferably approximately 56mm (for a pole diameter of approximately 300mm).
The threaded part of the nut 506, at the inner surface of the bore, can be for example 35mm long. It can also extend until the end of the bore 504 at the nut head 501. The threaded part of the nut 506 must be long enough to prevent the bolt 104 from tearing out at a sufficient degree of tightening. The bolt 104 can be cut to length so that it does not protrude from the nut head 501. The cylindrical wall 510 of the recessed part of the nut 508 should preferably be thick enough to provide sufficient strength, while not be so thick as to weaken the wooden pole 100 from excessive reaming for the nut recess 302. For example, an outer diameter 512 of the recessed part 508 of 25mm for a M16 bolt is suitable. In general, an outer diameter 512 of the recessed part 508 of about 130% to 180%
of the bolt diameter 514 is suitable, or preferably approximately 155%. These features provide the ability to tighten the nut 106 to the bolt 104 with a torque of 130Nm.
In a preferred embodiment the nut 106 has a wide enough head 501 to distribute the load so that nut 106 does not sink in (even without the use of additional washers). The wide head 501 also protects the hole 302 from dampness. In one embodiment, the nut head 501 is 70mm in diameter and 3.5mm thick, but different sized heads 501 may be used. For example a particularly weak pole may require a large nut head 501 to ensure that the nut head 501 does not sink into the pole 100. Unlike the recessed part of the nut 508, the head 501 sits against the surface of the pole.
In a preferred embodiment, at the threaded end 506 of the nut the shoulder 514 is shaped to assist insertion of the bolt 104 so that the bolt 104 self-centres to the centre of the nut 106. In the example illustrated here, the shoulder 514 is chamfered to guide the bolt 104 into the thread 506. Alternatively, the shoulder 514 can be rounded, tapered or angled. When the bolt 104 engages with the nut 106, the shoulder 514 centres the bolt to the lumen of the nut.
The nut can for example be fabricated from steel, and is preferably galvanised to European Standards (EN) after forming.
Figures 6 and 7 shows the nut 106 and tightening tool 600, and security nails and washer 700 used in the pole strengthening system (PSS) described above.
The nut head 501 is formed into an individual shape that fits a tightening tool 600 with a complementary shape. In the example illustrated here, the nut head shape 501 comprises two through holes 602 arranged in specific locations on the head 501. The tightening tool 600 has a complimentary shape with two studs 604 arranged in locations corresponding to the holes 602 in the nut head 501.
Different configurations may of course be used. For example, three holes may be used, or the holes may be eccentrically placed. Other types of complementary surface formations on the nut head and tightening tool may also be used to allow engagement between tool and nut.
Generally, a huge variety of modifications to the nut head 501 can be made to individualise the nut 106. This gives the advantage that different operators can be supplied with individual nuts and corresponding tools so that only that operator can remove the pole support element 102. By using non-standard, individualised nut and tool designs in this manner, the risk of tampering can be reduced because the nut cannot easily be removed with standard tools. Furthermore, as discussed above, the bolt head is also shaped so that it cannot easily be gripped with standard tools.
To improve security of the construction further, as well as to provide additional advantages, security nails 108 can be used. Security nails 108 may be hammered into the pole 100 through holes in the nut 106 so that they are flush with the nut 106 (as illustrated in Figure 2). In a preferred embodiment, the nails 108 have no heads; they simply fill the holes in the nut 106 so that the nut cannot be removed without tampering with the nails. The nails 108 may be inserted into the tightening holes 602 of the nut 106 until flush with the holes.
Here, the nails 108 prevent tampering with the nut 106, as the tightening tool can no longer be fitted into nut 106. Alternatively the nails 108 may be inserted into separate, dedicated holes in the nuts 106. The nails 108 are optionally threaded so that when they are tapped in, they screw themselves into the wooden pole 100. The nails 108 also prevent the nut 106 from rotating and hence loosening.
The nails 108 provide a further advantage in that one can easily tell if the tension of the bolt 102 has changed by the position of the nail 108. At a later inspection, if the nail 108 is not flush with the nut 106, but is sunk in or appears skewed, the nut 106 may have loosened (for example due to warping of the pole) and needs re-tightening. When the support element 102 is to be dismounted from the pole 100, the security nails 108 can be hammered further into the pole 100 so that the rotation of the nut 106 is no longer obstructed. Further, the same holes in the nut 106 can be accessed by the tightening tool 600 to loosen the nut 106. The 5 support element 102, bolts 104, and nuts 106 can then be re-used.
In some instances, a large plain washer 700, for example 100mm outer diameter, may be placed between the head 501 of the nut 106 and the pole 100. This washer 700 can help distribute the pressure exerted by the nut 106 over a wider 10 area of the pole 100, and can therefore enable additional tightening of the nut 106 and bolt 104, resulting in better connection of the pole 100 to the support element 102. In one example, the large washer 700 is formed from 4.0mm plate and is galvanised to European Standard (EN) after forming. However in embodiments using the security nails, the nut head 501 preferably has a large 15 enough diameter so that use of a washer 700 is not necessary, as the washer might otherwise obstruct insertion of security nails 108.
The features described above can make the pole strengthening system a safe, cost effective, practical and secure method of restoring a decayed pole to 20 serviceable condition.
PSS Installation Process Figure 8 shows one example of a device adapted to install the Pole Strengthening System as described above. The device is adapted to be fitted onto a mechanical excavator, tractor or other piece of machinery.
The installation device 800 attaches to a support member 102 by slotting a securing bolt (not illustrated) through holes 804. Holes 804 are positioned either side of the ridge 400, which has a corresponding hole 808 through it. The installation device 800 comprises a head part 806 which rests on the top of support member 102 which provides support when driving the support member 102 into the ground.
Installation device 800 comprises a hydraulic breaker 802 which moves reciprocally up and down, acting to push the support member 102 into the ground. This process is continued until the support member 102 is at the correct depth. The installation device 800 engages with the top of the support member 102 and extends down a point on the support member 102 above where the flanges 410 start to taper. When the support member 102 has been driven into the ground to a sufficient depth, the installation device 800 can be disconnected by removing the securing bolt. Ideally, this is a quick-release bolt. In one embodiment, this comprises a bolt with a handle attached so that it can be inserted and removed quickly.
Figure 9 shows an example process diagram of the installation of the pole strengthening system.
S1 Mounting: the support element 102 is driven down the side of the pole 100 into the ground using a pile drive method. This is ideally achieved using vibration driving using the installation device described above. The support element may for example be pushed into the ground at an angle, to ensure that the base of the support element pushes into the pole. Poles that have completely failed at ground level can be held in place. The ridge 400 in the support element 102 strengthens the support element 102, aiding both the insertion process and the strength of the support element 102 post-installation. The support element 102 does not require fixation to the pole 100 with concrete, for example. The support element 102 is then attached to the pole 100 using a system of bolts 104 and nuts 106 as described above.
S2 Drilling: as illustrated in Figure 3, holes 300 of the appropriate diameter for the bolts 104 are drilled through the pole 100 at the appropriate positions for attachment of the support element 102. At the hole outlet opposite the support element a recess 302 is drilled to accommodate the nut 106. For this purpose, a special drill bit 304 is used which has a narrower tip 314 of the same diameter 308 as the drill bit 304 for the bolt through hole 300; and is enlarged 316 at a distance from the tip to the same diameter 310 as the nut recess 302. For example, the tip 314 of the bit 304 may be 16mm diameter (for an M16 bolt), and further away from the tip the bit is enlarged 316 to a diameter of 25mm. This change is preferably a step-change, but may be a sloping change, or a series of small step changes. The tip 314 of the drill bit may not extend all the way through the pole 100, rather it just creates a guide hole for subsequent drilling with improved alignment.
The stepped drill bit 304 enables alignment of the recess 302 for the nut 106 with the bore hole 300 of the bolt 104. Thanks to this alignment the nut head 501 is flush with the pole 100, and the risk of the nut 106 and bolt 104 being misaligned is reduced. This can be beneficial in enabling sufficient tightening of the nut 106 to the bolt 106. The drill bit 304 may optionally have another shoulder (not illustrated) at some distance along the enlarged section 316 of the bit 304 to ensure that the nut recess 302 is of the correct depth 306. In the example discussed so far, this would be at 56mm along the enlarged section 316 of the bit 304. The drilling and mounting stages may alternatively be performed in the opposite order.
S3 Bolting: The nut 106 is inserted in the recess 302 opposite the support element 102, if necessary by knocking it in. From the support element side of the pole the bolt 104 is then inserted. The nut 106 guides the bolt 104 into the threaded section 506 by means of the chamfered or rounded shoulder 514. The bolt 104 is usefully pre-cut to the correct length so that it does not protrude out of the nut 106. Bolts 104 are inserted at cross-angles above ground, ideally at right-angles to one another, or as close to right angles as practical. The distance between pairs of bolts 104 is ideally as large as possible to reduce moment loads on the bolts 104. The bolts 104 are preferably heavily greased prior to fitting, to reduce the impact of water damage occurring.
S4 Tightening: The nut 106 is tightened to approximately 130Nm using a tightening tool. The bolt 104 is held rotationally in place by the non-circular section 516 engaging with holes 408 in the support element 102 as described above. Referring to Figures 6 and 7, the tightening tool 600 has a design corresponding to the design of the nut head 501. Ideally, it is of a non-standard design to minimise the chance of tampering. In one example, this design consists of two protrusions 604 spaced from the centre of rotation of the tool. These protrusions 604 then couple with correspondingly placed holes 602 in the nut 106. Alternatively, as described above, each operator or client can have their own nut tool with corresponding nut shape for tightening.
S5 Securing: Security nails 108 can then be tapped through holes in the nut to provide the advantages discussed above.
After installation as set out above, checks can be carried out as required to ensure the integrity of the installation. Finally, the pole strengthening system can be dismounted when no longer needed (e.g. when the pole 100 is taken out of service). These steps are summarised below:
S6 Inspection: In this step, the pole is checked to see if the support element is pulled in tightly against the pole 100. This can be by checking to see if security nails 108 are still intact and in the correct placement.
S7 Dismounting: The bolts 104 can be removed by unscrewing the nuts 106 with the specially adapted tightening tool 600 (after removing or tapping in the security nails 108 if used). The support elements 102 can then be extracted. Support elements 102, bolts 104, and nuts 106 can be reused. This reusability can provide environmental benefits.
Criteria for Assessment to determine suitability for strengthening In some cases, a pole 100 may be strengthened using the described system even if it is unserviceable for normal duties. There may even be little or no sound wood present at or below ground line. In an embodiment of the pole strengthening system, requirements might include:
= Internal Rot: Preferably at least 60 mm of sound wood measured at 1 metre above ground line (a Matson borer can be used to ascertain the amount of sound wood available).
= External Rot: External rot of treated sapwood should preferably not penetrate more than 20 mm, provided there is at least 70 mm of sound wood (probing the surface of the pole with a screwdriver, for example, provides information as to the extent of any external rot).
The above requirements are given purely as examples of requirements that might apply in a particular context or embodiment. Other embodiments and other application contexts may have different requirements, which may be more or less stringent.
It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.
For example, although the pole strengthening system has been described for reinforcing poles at ground level, any portion of a pole may be reinforced using the system, in which case the support element may be of a different shape (e.g.
instead of being tapered, the support element may have substantially the same width along its length, and additional bolts may be used).
Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.
Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

1. A system for supporting a pole, comprising:
a support element for supporting the pole; and fastening means for securing the support element to the pole;
wherein the fastening means comprises a pair of mutually engaging fastening parts, including a bolt part and a corresponding nut part adapted to engage with the bolt part; and wherein the support element comprises an aperture adapted to receive a first one of the pair of fastening parts, and wherein at least one of the aperture and the first fastening part is shaped to prevent rotation of the first fastening part when located in the aperture.

2. A system according to claim 1, wherein the aperture is shaped to prevent rotation of the first fastening part when located in the aperture.

3. A system according to claim 2, wherein the first fastening part has a shaped portion having a shape corresponding to the shape of the aperture so as to prevent rotation of the first fastening part when the shaped portion is located in the aperture.

4. A system according to any of the preceding claims, wherein the first fastening part is the bolt part.

5. A system according to claim 4, wherein bolt part comprises a head and a shaped portion shaped to prevent rotation of the bolt part, the shaped portion being proximal or adjacent to the head.

6. A system according to claim 5, wherein the bolt part is arranged, when fully inserted through the aperture, so that the head abuts a surface of the support element around the aperture and the shaped part of the bolt engages the aperture having a corresponding shape to thereby prevent rotation of the bolt.

7. A system according to any of the preceding claims, wherein the aperture and/or a portion of the first fastening part has a non-circular shape, preferably a rectangular or square shape.

8. A system according to any of the preceding claims, wherein the second fastening part is arranged for engagement with a fastening tool to enable rotation of the second fastening part.

9. A system according to claim 8, wherein the second fastening part comprises a head having one or more apertures for engaging complementary formations on the fastening tool.

10. A system according to claim 9, comprising one or more nails for insertion through the one or more apertures in the head of the second fastening part.

11. A system according to claim 10, wherein the nails are headless nails.

12. A system according to any of the preceding claims, wherein the second fastening part is the nut part.

13. A system according to claim 12, wherein the nut part is arranged to be recessed into the pole.

14. A system according to any of the preceding claims, wherein the support element comprises at least one support surface arranged to be placed against a surface of the pole to provide support to the pole.

15. A system according to claim 14, wherein the aperture is located in the support surface.

16. A system according to any of the preceding claims, wherein the support element comprises a plurality of apertures for use with a plurality of respective fastening means.

17. A system according to any of the preceding claims, comprising a plurality of support elements for fastening to the pole.

18. A support element for supporting a pole, preferably for use in a system as claimed in any of claims 1 to 17, the support element comprising:
at least one support surface adapted to be placed in contact with the surface of the pole to thereby support the pole; and at least one aperture adapted to receive a bolt for securing the support element to the pole, the aperture being shaped to prevent rotation of the bolt when the bolt is inserted through the aperture.

19. A support element according to claim 18, wherein the aperture is shaped to allow the bolt to pass through the aperture and to engage a correspondingly shaped portion of the bolt such that rotation of the bolt is prevented.

20. A support element according to claim 18 or 19, wherein the aperture is non-circular, preferably rectangular or square.

21. A support element according to any of claims 18 to 20, comprising a pair of apertures positioned so as to receive a pair of bolts which are angled relative to one another in a plane perpendicular to the radial axis of the pole.

22. A support element according to claim 21, wherein the apertures are arranged to give an angle between the bolts, when installed, of between 70° and 110°, preferably between 80° and 100°, more preferably substantially 90°.

23. The support element according to any of claims 18 to 22, wherein the support element has at least one ridge lengthwise.

24. The support element of any of claims 18 to 23, wherein the support element comprises two curved flanges arranged for placement against the surface of the pole, the curved flanges separated by a ridge extending along the longitudinal length of the support element.

25. The support element of Claim 24, wherein one or both of the flanges are tapered to assist in insertion into the ground.

26. A bolt for use in securing a support element to a pole, preferably for use in the system of any of claims 1 to 17, the bolt comprising a head and a shaft, the shaft including a shaped section, the shaped section shaped so as to prevent rotation of the bolt when the bolt is located in a correspondingly shaped aperture of the support element.

27. A bolt according to claim 26, wherein the bolt head is arranged to substantially prevent manipulation by a fastening/unfastening tool.

28. A bolt according to claim 26 or 27, wherein the bolt head lacks formations suitable for engagement by a tool and/or wherein the bolt head has a flat or dome-shaped, preferably substantially smooth, surface.

29. A bolt according to any of claims 26 to 28, wherein the shaft has a length of between 95% and 98% of the pole diameter, preferably substantially 97% of the pole diameter.

30. A nut for use in securing a support element to a pole, preferably for use in the system of any of claims 1 to 17, wherein the nut has a head and a body with a threaded bore; wherein the body is adapted to be recessed into the pole with the head protruding from the pole, and wherein the bore comprises a shoulder which is adapted to guide a bolt into the bore.

31. The nut of claim 30, wherein the shoulder is one of: chamfered; or rounded.

32. The nut of claim 30 or 31, wherein the nut head has a form arranged to fit a non-standard tightening tool.

33. The nut of any of claims 30 to 32, wherein the nut head comprises formations adapted to engage with complementary formations on a tightening tool, the formations comprising at least one of: one or more grooves; one or more recesses; one or more apertures; or one or more protrusions.

34. The nut of any of claims 30 to 33, wherein the diameter of the nut body is between 130% and 180 % of the bore diameter.

35. The nut of any of claims 30 to 34, wherein the diameter of the nut head is between 180% and 380% of the bore diameter.

36. The nut of any of claims 30 to 35, wherein the diameter of the nut head is at least 120% of the nut body diameter.

37. The nut of any of claims 30 to 36, wherein the nut head has one or more apertures adapted to receive one or more nails which can be inserted through the apertures into the pole.

38. The nut of claim 37, wherein one or more of the apertures for receiving nails are also arranged to engage with corresponding formations on a tightening tool.

39. A method for reinforcing a pole, the method comprising:
placing an elongate support element adjacent to said pole;
boring at least one bore hole through said pole;
for each bore hole, boring a recess adapted to receive a respective nut;
inserting through the support element and through each said at least one bore hole a respective bolt;
inserting in each at least one recess a respective nut; and fastening each bolt to a respective nut.

40. The method of claim 39 wherein two bore holes are angled to one-another in the radial plane of the pole and adapted to receive a bolt each.

41. The method of claim 39 or 40 wherein at least a portion of said bore hole and said recess are bored in a single step, preferably using a single tool.

42. The method of any of claims 39 to 41, further comprising inserting headless nails through apertures in the nut into the pole.

43. A drill bit, preferably for use with a system as claimed in any of claims 1 to 17 or in a method as claimed in any of claims 39 to 42, comprising a first section, preferably for drilling a bore through a pole to receive a bolt, and a second section, preferably for drilling a recess for a nut, wherein the first section has a first diameter, preferably corresponding substantially to the diameter of the bolt, and the second section has a second diameter larger than the first diameter, the second diameter preferably corresponding to the diameter of at least a part of the nut to be recessed into the pole.

44. A system for supporting or reinforcing a pole substantially as described herein with reference to and/or as illustrated in any of the accompanying drawings.

45. A support element substantially as described herein with reference to and/or as illustrated in any of the accompanying drawings

46. A method of reinforcing a pole substantially as described herein with reference to and/or as illustrated in any of the accompanying drawings.