Pipe clamps

Abstract: The invention relates to pipe clamps and is particularly concerned with equipment that combines ease of handling and transportation and which can ensure correct alignment of curved, polyethylene pipe ends (3,4) and their presentation to an appropriate coupling means. This objective is met by a construction comprising first and second clamp means (8,10), said first clamp means (8) being pivotally secured at or towards one end of an inflexible, extendible means (6) and said second clamp means (10) being pivotally secured at or towards the opposite end of said extendible means (6), the free ends of the clamp means being detachably and pivotally secured to each other.

Description: This invention relates to pipe clamps. The employment of polyethylene as the material for pipelines for gas and water distribution is now commonplace taking advantage of its important characteristics. In particular, the flexibility of polyethylene allows pipes formed from it and up to large diameters to be coiled at the point of manufacture for ease of handling and transportation that that provides. The disadvantage of this is that the coiling of polyethylene pipes induces a curvature in the pipe. In German Patent No. 230912 reference is made to a means and a mechanism whereby pipe clamps can be held in rigid axially aligned relationship, and be drawn towards and moved away from each other. However, German Patent DD-A-230912 does not attend to the problem of pipes having an induced curvature. Thus, on site and with one pipe laid e.g. in a trench, and the next pipe length coiled on a drum and ready for laying, the respective ends of the laid pipe and the coiled length are each curved, with an inevitable attendant difficulty in bringing the pipe ends together for jointing, by any one of the usual polyethylene pipe jointing techniques, electrofusion, butt fusion or socket fusion, all of which are very reliant on accurate pipe end alignment for the creation of an acceptable joint. This has led to the development of large and heavy clamping systems and alignment rigs that are inconvenient and slow to use and require considerable manpower for their effective use. The object of the present invention is to provide a pipe clamp that enables the accurate alignment of pipe ends and avoids those disadvantages mentioned above. A pipe clamp according to the present invention is disclosed in claim 1. Preferably pipe clamps are located on clamp supports, the clamp supports being pivotally attached to the extendible means, and to each other. With this form of construction, the means to maintain the clamp means in alignment may be positioned on the clamp supports. Further preferably two support arms are provided for each clamp with cooperating suport arms each pivotally secured to opposite ends of two inflexible extendible means. Preferably, the extendible means is a piston and cylinder, with one clamp support pivotally connected to the closed end of the cylinder, and the other clamp support pivotally secured to the end of the piston rod emerging from the cylinder. Further preferably, the free ends of the clamp supports are held together by a removable pivot pin. Thus, with the clamp supports disconnected from each other, and disconnected from the alignment maintenance means, each can be freely pivoted about its connection to the extendible means to put its clamp in a disposition to receive the end of a pipe, substantially irrespective of any particular upwardly angular disposition of a pipe end, e.g. extending out of a trench, or extending from a coiled length. With the pipe ends clamped in the clamps, the clamp supports can be swung with relative ease about their pivotal connections to the extendible means, to permit their pivotal connection together. The extendible means can then be extended, as a result of which, the clamp supports are brought into alignment and consequentially, the pipe ends brought into an aligned co-axial condition, to permit their successful jointing. With the clamp supports in alignment, each can be engaged by the alignment maintenance means on the other, to hold the clamp supports in alignment during movement of the pipe ends towards each other. When pipe clamps are located on clamp supports they may simply be of rectangular bar shape, and the alignment maintenance means in the form of a slip ring may be provided on one or both support bars. With the slip rings drawn rearwardly of the clamp supports, the first function of the pipe clamp of the invention, easy securing of the pipe ends in the clamps can be effected, and with the clamp supports aligned, the slip rings can be brought forward to lock the ends of the supports together, and permit the removal of their pivotal connection to each other and enable the second function of the invention to be performed. Alternatively a support block may be provided on one support arm of each cooperating pair of support arms and a roller pin removably secured to each support block, the support blocks and roller pins combining to form a guide for the support arms. Thus at the onset of operations, and with the ends of the support arms pivotally secured together, the roller pins can be removed and the extendible means contracted to cause the pivoting of the clamp supports on the extendible means and the folding of the clamp supports about their pivotal connection together to put the clamps in a condition where the pipe ends can be connected to the clamps. The extendible means are then extended to cause opposite pivoting of the clamp supports and to bring the clamp supports into alignment and when the roller pins are replaced to form guides for the clamp supports. The pivotal connection between the supports is then removed and the extendible means contracted to cause the clamps and hence pipe ends to move towards each other and enable connection of the pipe ends. One embodiment of the invention will now be described with reference to the accompanying drawings, in which:- Figure 1 is a schematic representation showing the general disposition of pipe ends requiring connection; Figure 2 is a plan view of equipment in accordance with the invention; Figure 3 shows the equipment of Figure 2 at the point of connection to the pipe ends; Figure 4 shows the equipment at an intermediary stage in bringing the pipe ends into alignment; and Figure 5 shows the equipment of the invention at the stage where the pipe ends are in alignment. As is illustrated in Figure 1, it is ordinarily the case that polyethylene pipe lengths 1 are coiled on a drum 2 at their point of manufacture, and with cosequent inducing of curvature of the coiled pipe. Thus, as is shown in Figure 1, the free end 3 of the coiled pipe assumes an upward curved disposition, as does the end 4 of a laid pipe 5, and to which the coiled pipe is to be attached. As is illustrated in Figures 2 to 4, equipment enabling the accurate aligning of the pipe ends 3 and 4 comprises a double-acting piston and cylinder unit 6 to each side , a rectangular-sectioned support arm 7 for a clamp 8, pivotally secured to the ends of the cylinders 6, and a rectangular-sectioned support arm 9 for a clamp 10 pivotally secured to piston rods 11 extending from the cylinders. Each clamp is of the type where a bottom clamp member is fixed to its respective arm, and a top clamp member removably secured to the bottom clamp member. Each of the support arms 7 and 9 is provided with a mounting member 12 for a removable roller pin 13 and towards their free ends, each arm 7 and 9 is provided with a respective co-operating hole 14, 15, to receive a pivot pin 16. Thus, and as shown in Figure 2, the roller pins 13 are removed, and each arm 7 and 9 swung about its pivotal connections by withdrawing the piston within the cylinder, to fold the arms 7 and 9 about the pivot pin 16 to enable the pipe end 3 and the pipe end 4 to engage in and be secured to the respective clamps 8 and 10, with the pipe end 4 projecting beyond the clamp 8 and the pipe end 3 projecting beyond the clamp 10. The piston and cylinder units are then activated by admitting pressure fluid to the cylinders 6 to drive the piston rods 11 out of the cylinders, and when the pivotal connections of the arms 7 and 9 to the cylinders and to the piston rods and the pivotal connection of the arms to each other by the pin 16 progressively brings the arms into alignment, as is shown by Figures 3 and 4, and hence brings the pipe ends into alignment, as is shown by Figure 4. When the arms 7 and 9 are in alignment, the roller pins are replaced to bridge the overlapping arms, and at this point, the pin 16 is removed. Pressure fluid is then admitted to the cylinders 6 to drive the pistons in the opposite direction and hence retract the piston rods within the cylinders, and because of the connections between the arms 7 and 9 and the cylinders 6 and piston rods, and the slidable engagement between the arms 7 and 9 and the roller pins 13, the result is that the clamps 8 and 10 and hence the pipe ends 2 and 3 are held in axial alignment as they are urged towards each other. Thus, by providing a suitable coupling member 17 between and in axial alignment with the pipe ends, the pipe ends can be driven into enagement with the coupling member. A coupling member of known character such as, for example, a coupling sleeve of the known electrofusion type, can readily be employed. Once the pipe ends have been coupled together, it is simply a case of releasing the pipe ends from the clamps by disconnecting the respective top clamp member, and when the equipment of the invention can readily be transported to the next location where the end of a coiled pipe is to be connnected to the end of a laid pipe.

Claims: A pipe clamp comprising first and second clamp means and a means of maintaining said clamp means in axial alignment during a movement of said clamp members towards and away from each other, induced by an inflexible extendible means, characterised in that the first clamp means (8) and second clamp means (10) are each pivotally secured at or towards a respective end of the inflexible extendible means (6), the ends of the clamp means (8, 10) remote from the respective pivots being detachably, pivotally secured together (16), and there being disconnectable alignment maintenance means (12, 13) to maintain, when required, said clamp means (8, 10) in an axially aligned position parallel to the line of action of said inflexible extendible means (6) and whereby with the pivotal connection (16) disconnected a contraction of the inflexible extendible means (6) causes the clamp means (8, 10) to be drawn towards each other with maintained axial alignment, and whereby with the pivotal connection connected and the disconnectable alignment means disconnected an extension of the extendible means causes the clamps to go from a non aligned to an aligned position. A pipe clamp as in Claim 1, characterised in that the pipe clamps (8, 10) are located on clamp supports (7, 9) the clamp supports (7, 9) being pivotally attached to the extendible means, and to each other. A pipe clamp as in Claim 1 or Claim 2, characterised in that the extendible means is a piston and cylinder (6), with one clamp support (7) pivotally connected to the closed end of the cylinder, and the other clamp support (9) pivotally secured to the end of the piston rod (11) emerging from the cylinder (6). A pipe clamp as in any of Claims 1 to 3, characterised in that the ends of the clamp supports (7, 9) remote from the pivotal attachment to the inflexible extendible means are held together by a removable pivot pin (16). A pipe clamp as in Claim 1 and Claim 2, characterised in that the clamp supports (7, 9) are bars of rectangular section, and the alignment maintenance means (12) are slip rings slidable between a rearward position where the supports (7, 9) can be pivoted for securing of the pipe ends (2, 3) to the clamps (8, 10) to a forward position when the supports (7, 9) are in alignment to hold the supports in axially aligned and slidable engagement. A pipe clamp as in Claim 1 and Claim 2, characterised in that the alignment maintenance means (12) are mounting members secured to each clamp support (7, 9) and a roller pin (13) detachably secured to each mounting member (12) and whereby with the clamp supports (7, 9) pivotally secured together and the roller pins removed, contraction of the extendible means causes a pivoting of the clamp supports and a folding of the clamp supports about their pivotal connection together, and extending the extendible means causes the supports (7, 9) to be brought into alignment and when the roller pins are replaced and the pivotal connection between the supports (7, 9) disconnected and following which contraction of the extendible means causes the closing of the clamps towards each other with the supports held in axial and slidable alignment.

Inventors: BRIDGSTOCK ERIC, BRIDGSTOCK, ERIC
Applicants: FUSION GROUP PLC
Application year: 1991
Main classification: F16L1
IPC codes: B29C65, F16L1