A pipe installation tool

Abstract

An underground pipe installation tool comprising: a pair of spaced apart first 71, 72 and second 73, 74 elongate lever elements; wherein each first and second elongate lever elements comprise: a pr

Description

Field of Invention

[0001] The present invention relates to groundwork tools in general and, in particular to a tool to assist in the handling of pipes and pipework in trenches, to assist in the laying, removing and replacement of pipes and pipework for small bore domestic drainage. Background to the Invention

[0002] All buildings - whether they are offices or domestic houses and flats require utility connections: fresh water in, electrical supply in, gas supply in, waste water out, surface water out and telecommunications cabling. Each pipe for fresh water, waste water gas, and cabling are identified by their colour. Additionally, ducting may be provided to facilitate the efficient routing, protection, and maintenance of essential utilities services, such as electricity, water, gas, and telecommunications. Both pipes and ducting are available in specific colours: Blue for water, Black for electrics; yellow for gas; grey for telecommunications; with orange and purple for street lighting, traffic signal and motorway communications. The installation of underground pipes and ducting for utilities pipes and cables is , ostensibly quite simple. A trench is dug (to the correct depth), lay the pipe or any duct and then pass the pipe / cable through the duct, and fill in the trench with the appropriate back-fill. However, complications can arise in the handling of the pipes.

[0003] Utility pipes such as water supply pipes must comply with national and regional regulations. In England and Wales, for example, all materials and fittings used must comply with Water Supply (Water Fittings) Regulations 1999. Additionally, the laws of physics need to be taken into account so as to enable flow without, for example, a pressure problem preventing reasonable flow rates - which is important with respect to waste water, especially foul water. When laying new water supply pipes, new pipe is pigmented blue (BS 6572: Blue polyethylene pipes up to nominal size 63mm for below ground use for potable water) and there is one class designed for a working pressure of 12 bar at 20°C in sizes up to nominal size 63mm, for below ground use for potable water. With respect to water supply pipe lengths of up to 40m, then the nominal inch or 25mm diameter pipe is sufficient; from 40m - 100m an inch and a quarter or 32mm is sufficient whilst from 800m - 2000m, supply pipe diameter of 63mm is recommended. With regard to drain pipes, which will tend to have a reduced head, the pipes need to be of a greater diameter and of a size to prevent / reduce the likelihood of so-called fatbergs and other solid waste, with pipes typically being 6" / 150mm diameter and 4" / 100mm in diameter with a concomitant increase in weight and difficulty in installation, especially when the manufactured from ceramic / concrete.

[0004] As will be appreciated, the wider the bore and the longer the length of a pipe, the greater a difficulty shall be borne by workmen in installation, noting that each and every water pipe needs to connected to an adjacent pipe, without seepage and the weight of the pipe together with this need can cause complications. Whilst lm plus diameter concrete pipes as used as main drains for installation under or adjacent highways may be manoeuvred with assistance from a digger, suspending a pipe length by the use of belts and / or chains, domestic installations are placed in the ground and connected typically by two or more groundsmen, noting that 3 - 6m of plastic pipe needs to be supported and connected coaxially with respect to adjacent, previously laid pipework. One groundsman to offer up and join adjacent ends whether by adhesive, grout or push-fit and one groundsman to lift, rotate and provide axial forces to assist in placement, noting that ceramic pipes are heavy and rigid albeit shorter than plastic pipes which provide less grip from their smooth finish and are generally longer, making connection not as simple as one would wish, taking into account a length of relatively flexible pipe needs support along its length to ensure coaxial mating of adjacent pipes.

[0005] Various types of tool have been developed to assist in the installation of pipework. US3653284 teaches of a vice-grip plier which is used to hold 1" plastic pipe as it is inserted into a well casing, but is employed to draw a pipe through a casing, rather than to assist in the placement and of adjacent pipes in a trench. US4344215 is another vicegrip plier positioning tool - for use in the welding of adjacent cast iron pipes. The tool is provided with first and second differently sized jaws which can assist in the maintenance of position of a pipe by gripping about a narrow portion of the pipe - the width of the jaw, referenced as a blade, is taught as being preferably corresponding to the width between the limbs of the jaw and that end of the blade which confronts the blade preferably has a V-shaped notch which matches the trough formed by the jaw. One of the clamping jaws is capable of substantial adjustment relative to the other to enable the tool to be used on pipes and fittings of considerably different size. CN213541588U teaches of a water supply and drainage pipe installation auxiliary tool for constructional engineering, the clamping mechanism comprises a first and second semicircular clamp elements a that are employed to clamp the pipe, with one of the clamp elements having a handle whereby a pipe-fitter can hold and support the pipe. After use, the clamp elements are released by undoing the clamp, as a separate procedure. OBJECT TO THE INVENTION

[0006] The present invention seeks to provide a simple, easily realisable and inexpensive solution to the problems discussed above. The present invention also seeks to provide a simple device for laying and removal of pipes and pipework which is simple, cost effective and can be used by a reduce number of personnel. The present invention further seeks to provide a tool which can easily operate with regard to a number of diameters of pipe. STATEMENT OF THE INVENTION

[0007] In accordance with a first aspect of the invention, there is provided an underground pipe handling tool for positioning and holding a tubular pipe element, the tool comprising: a pair of spaced apart first and second elongate lever elements; wherein each first and second elongate lever elements comprise: a proximal lever portion and a distal pipe grip portion, wherein the first and second elongate lever elements are pivotally associated with each other about a pivot axis, the pivot axis being between the lever portion and the grip portion of each elongate lever element; wherein the respective grip portions are shaped in correspondence with the dimensions of a pipe to be retained by the tool; wherein the pair of spaced apart first and second elongate lever elements are spaced apart by elongate members, which elongate elements are parallel with the pivot axis; wherein there is an elongate element extending between a proximal part of each pair of first elongate lever elements and an elongate element extending between a proximal part of each pair of second elongate lever elements, the elongate elements being fixedly connected to their respective proximal parts of the first and second elongate lever elements; wherein there is further provided an elongate member about the pivot axis, to assist in maintenance of rigidity of the tool in use; wherein the elongate members extending from the proximal parts of each pair of first and second elongate elements define handle elements, which handle elements can be operably brought together by an operator whereby the pair of spaced apart first and second elongate lever elements are arranged to be operable to grip a pipe element. The gripping of a pipe element can be considered to be similar to a manner similar to a pair of pliers; providing a groundsman with means to comfortably and reliably lift, handle, guide and rotate a pipe to be laid into the ground in accordance with regulations. As will be known to those skilled, handling of pipes of various weights and lengths, which need to be buried in the ground to a depth of lm or more (and getting deeper in line with a required fall over distance), typically in a trench with not much room for a groundsman to move is difficult; with wet and muddy pipes manual handling with the benefit of gloves is also difficult. Indeed, the tool in accordance with the invention scan provide greater degrees of grip and by having a handle, a groundsman operator can easily manoeuvre the pipe by twisting - as when introducing a pipe into a push-fit coupling bell / housing. Whilst a method of working with a pipe may be simplified for one person, in the case of a heavy clay pipe or an elongate 3m - 6m pipe, then two groundsmen can each operate such a tool in tandem, eliminating the need for an additional crane or an adapted digger device with a lifting chain.

[0008] Conveniently, the underground pipe installation tool comprises an elongate element, extending parallel with respect to the pivot axis, between a grip portion of at least one pair of first elongate lever elements and an elongate element extending between a grip portion of each pair of second elongate lever elements, the elongate elements being fixedly connected to their respective grip portions of the first and second elongate lever elements.

[0009] To ensure that it the underground pipe installation tool can be easily handled by an operator, the handle elements can be conveniently provided with rubber-grip covers. Preferably, the rubber handle portions define handgrips for gripping the two handles together by an operator. Additionally, it may be helpful for a tool to be provided with spring biassing means for urging the head portions of the levers away from each other, to assist in release of a pipe when required. Equally, it may be helpful for a ratchet system to be incorporated, such that once a pipe is gripped, the handles remain in position

[0010] The underground pipe installation tool can be adapted such that a respective pair of adjacent first elongate lever grip portions are each provided with a pivoting jaw member. The tool may be adapted such that each respective pair of adjacent second elongate lever grip portions are each provided with a pivoting jaw member. Given that the diameter of pipes should be the same, damage and irregularity in clay pipes can vary slightly: if one or both of the opposing jaws float to a degree - i.e. pivot about an axis on the elongate lever arm, rather than directly contacting elongate lever arm, then security of gripping can be increased.

[0011] The underground pipe installation tool may be arranged such that the elongate lever grip portions have a surface shape in correspondence with a minor arc of a portion of a pipe. This could be arranged such that a respective pair of adjacent first elongate lever grip portions are each provided with a pivoting jaw member and facing jaws are provided with a number of contact teeth, which can help in engagement of the jaw with respect to the pipe. The number of teeth may typically vary from one to ten, depending on the material of the pipe and the size of pipe - but could be more.

[0013] The jaws of the pipe installation tool can be provided with a rubber, polymeric or other material which may assist in engagement of the tool with respect to a pipe surface, it may be arranged such that one or more grip portions extend from a first distal lever grip portion of a pair to a second first distal lever grip of the pair.

[0014] It has been determined that the dimension of the underground pipe installation tool are generally in correspondence with the diameter of the pipe to be handled. Given that there are relatively few standard sizes of diameter of pipe, it may be found convenient to have a tool specific to a size of pipe. Notwithstanding this it may be more convenient to have a single tool with a number of pivot points on the elongate lever arm portions and pivotable jaws that can be pivotally mounted thereto, albeit, to take into account the need for the tool to open to a greater extent to whereby the same movement of the handle is ensured (to enable a comfortable grip in use). Additionally, the separation between the jaws / length of the elongate members can vary in length, but it has been found that it is conveniently between a length in correspondence to a diameter of the pipe to four times the diameter. Applicant has determined that if the distance is too short, then the grip is increasingly liable to slip

[0015] Applicant has employed aluminium of 5251 grade in the initial manufacture of the tool; it is readily obtainable in plate form and can be cut by many procedures such as laser cutting, water jet as well as traditional saws and is much lighter than tool steel. The plate can conveniently be of a thickness of 10mm for use in handling of 110 -160mm pipe. It will be realized that for larger pipe, the handling tool may be made of a more substantial construction; indeed the handles can be longer to exert more leverage, which may well be appropriate for the heavier clay and cast iron pipes. Whilst aluminium has a density far less than steel, tool steel can be employed - as indeed can a number of other materials such as reinforced plastics materials moulded or otherwise. Nonetheless, the elongate members if made from tool steel will provide greater durability.

[0016] By the provision of a range of sizes or adaptable jaws, a simple to use system can readily be provided to support a range of pipes of differing diameters, to assist in the supporting in carrying and connecting of pipes as they are being laid, a tool that is not too different from tools presently employed by builders, electricians and other like tradesmen. Brief Description of the Figures

[0017] For a better understanding of the present invention, reference will now be made, by way of example only, to the Figures as shown in the accompanying drawing sheets, wherein:- Figures 1 and la show a through-ground section of a residential water supply and a cross-section thereof; Figures 2 and 2a show, respectively waste water routes from domestic sewage and rainwater and a cross-section through a waste water trench; Figures 3a and 3b show, respectively, a length of pipe and a boss of a length of pipe having a push-fit receptacle; Figures 4a and 4b show male and female ends of a plastics pipe; Figures 5a, 5b and 5c show known pipe coupling elements; Figures 6a, 6b and 6c show typical procedures associated with handling drainage pipes as are prevalent in the industry; Figure 7 shows an end view of a first embodiment of the invention in a spaced apart fashion; Figure 8 shows a perspective view of the first embodiment of the invention in a spaced apart fashion; Figures 9 shows a perspective view of the first embodiment gripping a section of pipe; Figure 10 shows a variant of jaw design; Figure 11 shows a second variant of jaw design; Figure 12 shows how groundsmen can easily support an elongate pipe using a tool in accordance with the invention; Figure 13 shows how a pipe-to-pipe connection can be enabled using one or more tools in accordance with the invention and, Figure 14 shows how the tool can be employed in another application. Detailed description of the Preferred Embodiments

[0018] There will now be described, by way of example only, the best mode contemplated by the inventor for carrying out the present invention. In the following description, numerous specific details are set out in order to provide a complete understanding to the present invention. It will be apparent to those skilled in the art, that the present invention may be put into practice with variations of the specific.

[0019] Figures 1 and la show a through-ground section of a residential water supply form a stop tap 11 to pavement water connection 12 for water supply, with Figure la indicating the spacing in a trench 17 required for the placement of a water supply pipe 13 with regard to other utility supplies, such as gas 14, telecommunications 15 and electric 16 services. Figure 2 indicates corresponding waste water routes from domestic sewage and rainwater are indicated in relation to a simplified section of a house 20 with reference to sewage 21 and rainfall 22 drains, with Figure 2a indicating a cross-section through a trench 24 with a pipe 25 being supported by shingle in the haunch 26 are upon bedding 27, which in turn rests upon a foundation layer 28, if required, which in turn rests upon an earth base 29 of the trench.

[0020] Most houses and other residential properties in the UK have used two types of pipe work for underground drainage since the late 1970's, namely clay and plastics piping, with UPVC being the preferred plastics material. Indeed, UPVC is more commonly used since the pipe lengths are typically of 3m in length - but can be 6m or longer, thereby reducing the number of joins that are required to be made between adjacent pipes, noting that clay pipes are typically 1.5 m or so in length. Figure 3a show a typical length of 110mm diameter 3m length of uPVC pipe 30; Figure 3b shows a butt end 33 connection of a plastics pipe 32 which does not connect via separate couplers, rather each pipe has clay's main benefits are its strength and durability / longevity, plus it has a good environmental profile from a raw material through manufacturing, installation, in-use to end of life. This is considered by some as being the best since it is sustainable, durable, cost-efficient and provides a high-performance sewerage solution. However, there is a downside: for a 4" diameter pipe of 1.6m length, the weight is around 15Kg; an 8.25" diameter pipe of 1.75m length, the weight is around 31Kg.

[0021] Cast-iron sewer pipe, like clay pipe, is associated with older homes, yet it is still - albeit rarely - installed today. One of the best things about cast iron pipe has considerable internal strength against high pressures. A 4-inch diameter sewer pipe can withstand well over 350 psi. By contrast, clay, ABS, and PVC pipe are all subject to breakage at such pressures. On the other hand, plastics pipe runs must be encased in a 10mm pea shingle layer or fine gravel mix, before larger grade material can be placed on top for compacting and then receiving top layer of back fill and can generally absorb temporary pressures, due to vehicular movement. Furthermore, in regions where there is, or might be, soil movement due to topography, precipitation and climate, it is advisable to use vitrified clay pipe or cast iron pipe, which pipes have significantly greater structural strength and are not so dependent upon the use of back fill materials to provide necessary resistance to ensure stability.

[0022] One of the key benefits of (u)PVC soil system fittings is that it is one of the most durable plastics around and PVC is a common, strong but lightweight plastic used in construction. Plastics pipes typically weigh 94% less than their concrete equivalent. Due to their lightweight nature, plastics pipes and fittings help to reduce energy use and therefore greenhouse gas emissions. It is made softer and more flexible by the addition of plasticizers. If no plasticizers are added, it is known as uPVC (unplasticized polyvinyl chloride) or rigid PVC. uPVC is used for the majority of plastic pipes in the world, as it is incredibly resistant to chemical erosion and has smoother inner walls that help to encourage water flow. It also functions well in a wide range of temperatures and operating pressures. It is incredibly strong, stiff and cost-effective, and so is often used for sewage lines and exterior drainage pipes. Neither PVC nor uPVC is used to supply drinking water. cPVC (chlorinated polyvinyl chloride) is used instead.

[0023] Deformation of flexible pipes must occur if the pipe-soil system is to reach equilibrium. Therefore deformation is not detrimental but a natural action allowed for in flexible pipe design. The deformation of flexible pipes under load results in the ovalisation of the pipe (typically a 1-4% reduction in the vertical diameter and an increase in the horizontal diameter). As the horizontal diameter of the pipe increases, it derives support from the sidefill and trench wall. This passive earth pressure increases as the pipe deforms further until the pipe-soil system comes into equilibrium. Further deformation will not occur thereafter unless a higher vertical load is applied to the pipe-soil system or consolidation (or creep) of the materials occurs over a long period of time. European testing on flexible pipes has shown that pipe deformations of more than 30% can occur in practice without signs of structural failure. However, it is accepted that a limit on vertical deformation is necessary to ensure adequate long term pipe performance. Appropriate deflection (serviceability) limits should be set on a case by case basis. The duration of time is dependent on soil and installation conditions but generally less than two years.

[0024] Traditionally, clay pipes were fastened to each other by the use of cement - and cast iron pipes by welding or molten lead or rope-caulking, but now, in common with modern plastic pipes, push-fit couplers are employed. Moreover, with push-fit couplings plastic pipes can be coupled to cast iron as easily as to clay, or indeed plastic pipes. Nonetheless, it should be mentioned that plastics pipes can also be fastened using solvents, where the UPVC or PVC pipe ends are coated with a solvent, conveniently applied to one or both parts of a hub and spigot arrangement. Solvent weld soil system fittings provide watertight and permanent connections to a drainage system. Subject to correct application of solvent, these permanent bonds between pipes can ensure the integrity of a stem is maintained, with leakages and any potential spills being prevented.

[0025] Regular push-fit soil system fittings are widely manufactured with 110mm / 160mm / 210mm diameters and are considered to comprise the essential plumbing components used in a wide variety of underground drainage systems, whether that is residential, industrial or commercial. These sizes correspond to traditional 4", 6" and 8" pipe diameters and are therefore compatible with a majority of new and extant drainage systems, and it is notable that push fit products don't require any special equipment or tools in order to efficiently incorporate them alongside other products, given the resilience of the rubber / polymer sealant inserts in the butt ends of the pipe. Whilst 110mm push-fit soil system pipes can readily transport sewage and other general wastewater away from domestic buildings into their respective sewer or septic systems, it will be appreciated that in blocks of flats, and business premises, the larger diameter pipes will be more suitable. The larger diameter pipe will necessarily reduce the chances of obstructions occurring, in correspondence with the greater service requirements of larger buildings.

[0026] Referring now to Figures 4a and 4b there is shown a female hub element 41 of a pipe 40, which has an inside diameter sufficient to accommodate a circular rubber seal (not shown), which can sealingly engage with the outside of the male end 42 (spigot) of the pipe of figure 4b. Marking 42 is indicated to assist in confirmation of the connection being fully inserted. In contrast, Figures 5a and 5b show a rubber coupling element 50 and a pipe 51 with a rubber coupling element attached to a first end of the pipe. Figure 5c shows a coupling element 52 suitable for connecting two pipes having different diameters, conveniently fastened to respective pipe portions by appropriately sized first and second worm drive hose clamps, 53, 54, albeit other types of band clamp can be employed. It is to be noted that with waste water, pipes flow from a minor diameter to a major diameter - or otherwise blockages may all too easily arise.

[0027] Whether push-fit connections or more traditional cemented bonding adhesives are employed, when taking into account the need to offer up the end of one pipe against another coupling or within a receiving mount, it will be realized that the pipes need to be coaxial with respect to each other. Additionally, where a pipe emanates from within a building to the outside, rocker pipes of a length of 600mm are provided with at a boundary, as defined by lintels etc. at the edge of a building regard to plastics pipes, to accommodate localized settling, which is likely to occur over time, typically over the months after building has taken place. Figures 6a indicates how a tracked excavator 60 is utilized to carry a drainage pipe 61; in one alternative, Figure 6b shows how two groundsmen 62 transport a plastics drain pipe 63; Figure 6c shows how a large diameter ground pipe 64 is connected, with a lever action enabled by lever bar 65, pivoting with respect to the earth against a board 66 in an abutting relationship to an open end of a pipe.

[0028] Figures 7 and 8 show a first example of a tool 70 in accordance with the present invention presenting, respectively, an end view and a perspective view, from one side, of the tool. The tool 70 comprises: a first pair of first and second elongate lever elements 71, 72, which are pivotable about a pivot axis PA which are spaced apart from a second pair of spaced apart first and second elongate lever elements 73, 74, which are pivotable about the same pivot axis PA. The first and second pairs of elongate lever elements are separated at least by three parallel spaced apart elongate members 75a, 75b and 76, providing a triangular frame enabling pivoting of the handles toward each other in use. Specifically, when the handles are retained by an operator's hand, respective first and second grip handles 75a, 75b pivot about the pivot axis PA by an amount of movement m and, in turn, the distal ends of the tool (from the handle) define jaw elements 71, 72, 73, 74 which move apart to enable a pipe member 80 to be picked up (see Figure 8). That is to say the jaws open to extend about the diameter of the pipe - noting that the jaws also move with respect to the pivot axis to define an arcuate movement M.

[0029] It will be realized that the pivot motion can be enabled in a variety of fashions: the pivot spacing element 76 could be fastened to the outermost lever arm elements 72 and 74, and the two innermost lever arm elements of each pair of elongate elements pivot about a circular bearing part of the pivot spacing element. Conveniently, an inner shoulder is provided to the circular elongate element to ensure that stability of the pivoting element is maintained. Equally, fourth and fifth elongate elements 77, 78 could be placed between the jaws, whereby rigidity is ensure the a specific arrangement of the pivot. The bearing surface of the lever arms about the pivot spacing member 76 are conveniently plain bearings, but at a cost, could equally be provided as taper roller, needle or ball bearings. The pivot spacing member 76 can the attached to lever elements 72 &74 by screwthreaded bolts which provide an ability to service and re-grease the pivot bearings - albeit the other elongate elements would also need to be so attached, to enable full disassembly. On the other hand, crimp fastening, welding or event heat shrink locking could be employed, but whilst weld fastening is probably the easiest to conduct, to provide a relatively cheap tool, care should be taken in selection of the materials: conveniently, the pivot axis elongate element would be best made from a tool steel which has been hardened about the bearing surfaces and may not easily weld with the lever arms, if made from, for example certain types of aluminium, which would be selected for lightness, noting that a lightweight tool will be more easily managed in use by a groundsman. Aluminium alloys and steel are distinct with respect to their respective metallurgical and physical properties, such as thermal conductivity and melting temperature. Generally, steel's melting temperature is around 1370°C, more than twice that of aluminium that melts at around 660°C.

[0030] Referring again to Figure 9, it will be seen that the inside surfaces 82, 84 are shaped in relation to a specific size of pipe - that is to say the inside surface defines an arc having a radius in correspondence of the jaws 71, 72, 73, 74. Figure 10 shows a further variant, wherein, instead of having arcuate inside surfaces, 82, 84, upstanding elements 95 could be provided, which, if formed from the jaw member itself can provide detent means, which could grab relatively softer uPVC pipes - as opposed to clay or metallic pipes. In contrast, if separate and comprise rubber / polymer based resilient materials could better grab hard materials such as clay, concrete and steel pipes.

[0031] In the case, where the external surfaces of the pipe are damaged or of a non-uniform nature, with reference to Figure 11, one of each set of pivoted elongate lever arms 101, 103 can be provided with a pivoting grip element. In particular pivot element 105 is pivotally mounted about pivot 106 to lever arm 101; equally, pivot element 107 is pivotally mounted about a pivot (not shown) to lever arm 103. It will be appreciated that the pivot elements can present and arcuate surface, have detent element or provided with polymeric grip elements as discussed above.

[0032] Referring now to Figure 12, there are shown two groundsmen 111, 112 carrying a 6m length of drainage pipe 110, each of the groundsman having a pipe tool 70 in accordance with the present invention. Figure 13 shows how the connecting end of a loose pipe 120 is urged forward towards the butt end 121 of a previously laid pipe 122. Within the butt end 121 is a short length of a coupling nitrile not indicated - which is cleaned prior to the approach of the lose pipe. Ideally, the pipe 120 has a chamfered entry portion - but if not present, then a chamfer can be created to assist in the coupling process, noting that swarf from the chamfer action should be removed from the area of the join. Lubricant is then applied to the pipe ends, in accordance with procedure for a particular manufacturer. Groundsmen are not shown within the trench 124 to aid understanding, nonetheless, the tool 70 is seen with the handle sections 75a,b to the right hand side of the pipe. Arrows 125 indicate forward motion of pipe 120 relative to the previously laid pipe 122, whilst broad arrows 126 indicate rotational movement of the pipe, assist insertion, noting also that the handle sections 75a, b enable the vertical position of the pipe to be easily controlled. Ideally this procedure is undertaken by two groundsmen - noting that their movements will need to be synchronized to enable simple installation, albeit, it has been found, that the procedure can be undertaken by a single groundsman. It will be understood, that once the pipe 120 is pushed firmly hoe within the receiving end of the pre-existing pipe, checks are performed to ensure that the pipes are fully home - as indicated by marks that are provided with some makes of pipe. Equally, if the pipes do not have butt ends, then the respective ends must be checked, to ensure that the collar on one pipe has been dislodged.

[0033] It will be appreciated, that the trench may have boarding along the sides or some other support; the width of the trench may limit the amount of rotational to and from movement possible. In a stable native soil, the trench width must only be wide enough to permit the adequate placement and compaction of the embedment materials around the pipe. Stable trench walls enhance the structural integrity of the system when the trench is relatively narrow; as a result, it is desirable to only disturb the amount of soil as necessary for the pipe installation. Trenches that are too narrow make it difficult to correctly place the backfill. Trenches that are too wide can take more time to construct and can require more backfill; however, they may not be as stable as the undisturbed native material. Obviously, where the soil has a high sand content, trench widths need to be greater and with soils having a high clay content, trench widths can be less. One also needs to take into account the requirement for a fall basis in the pipe to ensure flow - very often there is a minimum of a 25mm fall per meter length, but this may need to increase on a site specific basis, together with natural undulations of the surface which may increase the amount that is removed. Any bricks that may have been employed for temporary support will need to be replaced by pea shingle, as an initial backfill which will provide free flowing support whereby in use, despite for example, a lorry or car that is positioned above the pipe, will provide sufficient resistance and spread the forces about the trench, without causing the pipe to break. A final backfill is subsequently placed over the initial backfill up to the final ground surface.

[0034] In the examples discussed above, the tool in accordance with the invention has be shown as a pipe fitting tool. It will also be realized, for example, when an extension to a building is being built, then a drain pipe may need to be changed, for example, to permit another bathroom to drain to feed into a pre-existing drain. In such circumstances the tool in accordance with the present invention may be employed to loosen a downstream pipe having a push-fit connection with an adjacent upstream pipe, typically by initially twisting the downstream pipe, to break any calcification that may be present or any seal that may have form due to sludge etc. that has caused two adjacent pipes to become locked together. Once this has been performed, then the pipes need to be separated by pulling one pipe from another, noting that in some circumstances, it has been found necessary to use another tool, to prevent the adjacent pipe from twisting or otherwise becoming loosened at an end distal to the proximal end pipe which is desired to be released.

[0035] Figure 14 shows another application of the present invention. In this instances, the tool 70 is placed upon a bench or work surface 140 and 5 a pipe 141 is placed within the jaws of the tool. Using a scribe 142 against an outside edge face of the distal pipe grip portion or jaw 143, whilst rotating the pipe 141, a guide line for cutting the pipe can be simply formed, whereby an angle grinder or saw or other suitable cutting tool can usefully be employed to create a straight edge termination, perpendicular 10 to the central axis of the pipe.

[0036] While particular embodiments of this invention have been shown in the drawings and described above, it will be apparent, that many changes may be made in the form, arrangement and positioning of the various elements of the combination. In consideration thereof, it should be 15 understood that preferred embodiments of this invention disclosed herein are intended to be illustrative only and not intended to limit the scope of the invention.

Claims

1. An underground pipe installation tool for positioning and holding a tubular pipe element, the tool comprising:a pair of spaced apart first and second elongate lever elements;wherein each first and second elongate lever elements comprise:a proximal lever portion and a distal pipe grip portion, wherein the first and second elongate lever elements are pivotally associated with each other about a pivot axis, the pivot axis being between the lever portion and the grip portion of each elongate lever element;wherein the respective grip portions are shaped in correspondence with the dimensions of a pipe to be retained by the tool;wherein the pair of spaced apart first and second elongate lever elements are spaced apart by elongate members, which elongate elements are parallel with the pivot axis;wherein there is an elongate element extending between a proximal part of each pair of first elongate lever elements and an elongate element extending between a proximal part of each pair of second elongate lever elements, the elongate elements being fixedly connected to their respective proximal parts of the first and second elongate lever elements;wherein there is further provided an elongate member about the pivot axis, to assist in maintenance of rigidity of the tool in use;wherein the elongate members extending from the proximal parts of each pair of first and second elongate elements define handle elements, which handle elements can be operably brought together by an operator whereby the pair of spaced apart first and second elongate lever elements are arranged to be operable to grip a pipe element.

2. The underground pipe installation tool according to claim 1, wherein there is an elongate element extending between a grip portion of each pair of first elongate lever elements and an elongate element extending between a grip portion of each pair of second elongate lever elements, the elongate elements being fixedly connected to their respective grip portions of the first and second elongate lever elements.

3. The underground pipe installation tool according to claim 1 or 2, wherein the handle elements are provided with rubber-grip covers.

4. The underground pipe installation tool according to any one of claims 1-3, wherein the handle portions define handgrips for gripping together by an operator.

5. The underground pipe installation tool according to any one of claims 1-4, wherein the respective pair of adjacent first elongate lever grip portions are each provided with a pivoting jaw member.

6. The underground pipe installation tool according to any one of claims 1-5, wherein the respective pair of adjacent second elongate lever grip portions are each provided with a pivoting jaw member.

7. The underground pipe installation tool according to any one of claims 1-6, wherein the elongate lever grip portions have a surface shape in correspondence with a minor arc of a portion of a pipe.

8. The underground pipe installation tool according to any one of claims 1-6, wherein the elongate lever grip portions are each provided with a number of contact points to enable a secure grip with a pipe.

9. The underground pipe installation tool according to any one of claims 1-6, wherein at least some of the elongate lever grip portions provided with a rubber grip surface.

10. The underground pipe installation tool according to any one of claims 1-6, wherein one or more grip portions extend from a first distal lever grip portion of a pair to a second first distal lever grip of the pair.

11. The underground pipe installation tool according to any one of claims 1 - 10, further comprising spring biassing means operably arranged to urge the jaws away from each other, to assist in release of a pipe when required.

12. The underground pipe installation tool according to any one of claims 1 - 11, further comprising a ratchet and detent release mechanism, such that once a pipe is gripped, the handles remain in position13. The underground pipe installation tool according to claim 1, wherein the length of the elongate members correspond from a length in correspondence to a diameter of the pipe to a length in correspondence to four times the diameter.

14. The underground pipe installation tool according to claim 1, wherein at least one distal pipe grip portion element has an edge that grips the pipe that is perpendicular to the pivot axis, which edge can be used with a scribe to assist in the marking of a pipe.A