GB2293223A

GB2293223A - Pipe clamping and scraping

Info

Publication number: GB2293223A
Application number: GB9518499A
Authority: GB
Inventors: Gerald Didier Lee
Original assignee: Fusion Group PLC
Current assignee: Fusion Group PLC
Priority date: 1994-09-15
Filing date: 1995-09-11
Publication date: 1996-03-20
Also published as: GB9418569D0; DE19533949A1; JPH08226577A; GB9518499D0

Description

2293223 PIPE CLAMPS This invention relates to pipe clamps.

The employment of polyethylene as a 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 and installation that that provides. The disadvantage of this is that the coiling of polyethylene pipes induces a permanent curvature in the pipe.

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.

A first objective of the present invention is to provide a pipe clamp that enables the accurate alignment of pipe ends and avoids those disadvantges mentioned above.

In the particular context of the employment of pipe jointing by the electrofusion technique, it is of paramount importance that the ends of pipes to be inserted into an electrofusion sleeve are normally prepared by the removal of a thin layer of material to expose a clean surface for jointing. Hitherto this has involved the hand cleaning and scraping of the ends of the pipes by an operative, a laborious and time- consuming exercise that offers no guarantees that the pipe ends are totally clean around their full peripheries and over the length of pipe end to be inserted in an electrofusion sleeve.

It is therefore a second objective of the invention to provide simple and efficient means for the automatic scraping of pipe ends that eliminates those problems mentioned above.

According to a first aspect of the present invention, a pipe clamp comprises first and second clamp means each pivotally mounted on a support member, drive means extending between each said support member and its respective clamp member, a pivotal connection between each drive means and its respective clamp means and at least one of said clamp means and its associated support member being movable with respect to said other of said clamp means and associated support member.

The drive means extending between the respective support member and clamp means may simply be a threaded rod extending through a threaded hole to one side of the respective support member, with a drive nut to one end of the threaded rod and a ball connection at the opposite end to engage in a socket attached to the respective clamp such as by way of an actuator plate attached to the clamp means to which a socket to receive the ball is secured. By simple rotation of the threaded rod, the angular disposition of each clamp means can be adjusted to suit the angular disposition of the end of the pipe length to be secured in a respective clamp. In practice, it will be the case of one pipe length already laid in, e.g. a trench, with its pipe end angled upwardly and the next pipe length on a coil waiting to be laid in the trench that ordinarily would also have its end angled upwardly. The invention therefore permits each clamp to be set at an angular disposition to ease considerably the location and securing of the pipe ends in the respective clamp, following which opposite movement brings the clamps and thus the end of the respective pipe to an aligned disposition.

To enable a respective movement as between the clamps and their respective support member, one support member and its clamp may be secured to the closed end of a doubleacting piston and cylinder, and the other support member and its clamp secured to the end of the rod emerging from the cylinder. Thus, by actuating the hydraulic cylinder, the clamp and its support secured to the end of the rod can be drawn towards or urged away from the clamp and support mounted on the cylinder, as required.

For added stability, one or more additional guide rod(s) may be provided adjacent the hydraulic cylinder and to which the support means secured to the cylinder is also attached and on which the support means attached to the rod is slidably mounted.

The clamp means of the invention may be mounted on a sled, for ease of transport but more particularly to enable the clamp means to be located on the ground immediately adjacent a trench or located in the trench with the ease of loading pipe ends into the clamps that it provides, with the guarantee that the pipe ends will be set in alignment and in readiness for securing together. Once loaded in the clamps and aligned, such as an electrofusion sleeve can be located on the pipe end extending from the fixed clamp, and the piston and cylinder activated to draw the movable clamp and its pipe end to a position where that pipe end is inserted into the opposite end of the sleeve following which the sleeve can be connected to a source of electrical supply for electrofusion of the sleeve to the pipe ends to be effected.

In accordance with a second aspect of the invention, a pipe clamp comprises first and second clamp means, a means of causing a respective movement of at least one clamp means with respect to the other, a scraper attachment located between said clamp means and adapted for movement with respect to said clamp means, at least two oppositely directed scrapers on the scraper attachment, and mounted for rotation about the axes of the clamp means and a drive means to cause said rotation of said scrapers.

Thus, with a pipe clamp such as has been discussed above where the clamp means are on supports attached to a double-acting piston and cylinder, with adjacent stabiliser slide bars, a support block may be slidably located on the -5 slide bars and to which the scraper attachment can be detachably secured. Thus, following the loading of pipe ends in the clamp means and the bringing of the pipe ends to the aligned position, the scraper attachment can be secured to the support block and the piston and cylinder activated to draw the clamp on the cylinder rod and its pipe end into engagement with the scraper to that side of the scraper attachment, the drive means to rotate the scraper being simultaneously activated to cause the scraper to rotate around and scrape the periphery of the pipe with the pipe end progressively moving across the scraper, until such time as that pipe end engages the scraper attachment to move it bodily along the slide bars to bring the opposite scraper into engagement with the pipe end of the fixed clamp with progressive movement of the scraper along that pipe end with continued rotation of the scraper. As a result there is the scraping of the pipe ends to a required degree along the length of the pipe ends with the guarantee that scraping will be effective around the full periphery of both pipe ends.

As an alternative, where the scraper is again mounted on a support block slidably located on slide bars, the oppositely directed scrapers are initially latched in an inoperative position, and a first movement of one clamp and its associated pipe end urges the pipe end into the scraper to contact release means and bring the scraper(s) into contact with the pipe at a distance along its length. Continued movement of that clamp causes the movement of the scraper and slidable support block to push the scraper at the opposite side over the end of the pipe secured in a fixed clamp to that side of the equipment. Again, the scraper(s) is initially latched in an inoperative position, and released into contact with the pipe surface when the pipe has contacted release means located on the scraper. on withdrawing the first clamp and pipe, with a simultaneous rotation applied to the scraper, the first pipe end is scraped clean as it is pulled clear of the scraper to that side. At that point connecting rods extending from the first clamp are brought into contact with the support block for the scraper to draw it clear of the pipe end on the fixed clamp, to scrape clean that pipe end as the support block is.withdrawn.

To foreshorten the time taken to scrape both pipe ends, a means can be provided whereby the scraper attachment is caused to move towards the fixed clamp simultaneously with the movement of the movable clamp towards the scraper attachment. In one form of construction movement of the scraper attachment is consequent upon the movement of the movable clamp and whereby the pipe ends are simultaneously scraped. This can be achieved by providing a Z-1inkage pivotally secured to the support for the scraper attachment with the ends of the links pivotally respective clamp supports and whereby movable clamp towards the scraper attachment causes a movement of the scraper attachment towards the fixed clamp, the Z-1inkage causing the scraper attachment to move towards secured to the movement of the the fixed clamp at one-half the rate that the movable clamp moves towards the scraper attachment and such that there is the equal and simultaneous scraping of the pipe ends.

As an alternative, equal and one-half rate of movement can be achieved by providing spring-loading means as between the scraper attachment and the respective fixed and movable clamps with the ratings of the springs specifically chosen to ensure the simultaneous and equal progression of the scrapers across the respective pipe ends.

Also possible is the provision of a separate drive means such as for example a hydraulic drive for the scraper attachment, to be activated simultaneously with the drive means for the movable clamp, whereby and again, to provide for the simultaneous scraping of both of the pipe ends.

One embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a part sectional side elevation of a pipe clamp/pipe scraper; Figure 2 is a section of the line II-II of Figure 1 to a larger scale; and Figure 3 is a plan view of a part of Figure 1, to a larger scale, with the scraper attachment removed.

in the drawings, a pipe clamp means 1 that enables the accurate alignment of pipe ends 2 has pipe clamp members 3, 4, each pivotally mounted on respective supports 5, 6, which supports are located between side plates 7 of the clamp means, the side plates further serving the purpose of -Bskids to enable the pipe clamps means to rest on the ground.

To ease the movement of the pipe clamp means along the ground, one or more wheels 8 may be provided towards one end of the pipe clamp means.

To each end of the pipe clamp means, frame members 9 are provided with threaded holes through which can pass a respective threaded rod 10, 11, each of which terminates in a ball for attachment to a respective universal coupling 12, 13, secured to a respective extension 14, 15, to the clamps 3, 4. Thus, the rotation of a threaded rod 10 or 11 causes its clamp member 3, 4, to rock about its pivotal connection to the respective support 5, 6, to put the clamp axis at a disposition to suit the angle of a pipe end as it, for example, might lie in a trench or as it might lie extending from a transport coil. With each clamp member being in two halves, the top half to each clamp can be removed, a pipe end laid on the clamp on the bottom half and the top half replaced and locked to the bottom half by appropriate bolts. Rotation of the bolts 10, 11 in the required direction causes the clamps to swing about their pivotal connection to the support until such time as the longitudinal axis of the clamps and the pipe ends located in the clamps are brought to a horizontal, aligned condition. As is shown more particularly by Figure 2, the support 6 is provided with wheels 16 lying in runners 17 located on the inner faces of the side plates 7. The support 6 has a bridging member 18 having holes 19 therethrough in which is positioned and secured the end of a respective cylinder 20 of a piston and cylinder arrangement, the piston rod of the piston and cylinder arrangement extending to and being secured to the support 5 which of itself is secured to the side plates 7. The bridging member 18 has further holes 20 through which extend guide bars 21 extending partway along the length of the clamp means, as will be discussed below, and there being a further hole 22 through which passes a slide bar 23 extending along the full length of the pipe clamp means.

Between the clamp members 3 and 4, a scraper attachment 24 is provided, detachably secured to a mounting 25 having wheels 26 located in the runners 16. To either side of the mechanism a rotatable socket-like member 27 is provided each having at least two oppositely-directed blades 28, which blades are retractable to an inoperative position and extendable to an operative position by movement of a latch mechanism 29.

In somewhat similar manner to the clamp 6, the mounting 25 for the scraper attachment 24 has through holes for the cylinders 20 the slide bar 23 and the rods 21, the length of the rods being such that they extend marginally beyond the support 25 to collar members secured to the ends thereof.

Thus, with pipe ends clamped in place, and brought to a horizontal and aligned condition, the pipe ends can be prepared in readiness to receive such as an electrofusion coupling sleeve. To enable this, the piston and cylinder units 20 are activated to cause the clamp 6 and its pipe end 2 to move towards the clamp 5 and its pipe end. Movement of the clamp 6 introduces its pipe end 2 into the socket-like member 27 until the pipe end contacts the latches 29 to release the scraper blades 28 that then contact the outer periphery of the pipe end. A continued movement of the clamp 6 causes the scraper attachment 24 to be moved bodily towards the fixed clamp 5 and its pipe end, the socket-like member 27 to that side passing over the pipe end until the pipe end contacts the latches 29 to release the blades 28 into contact with the outer periphery of that pipe end.

With the socket-like members caused to rotate, and the piston and cylinder units reversed, the clamp 26 is pulled away from the clamp 25, causing its pipe ends 2 to be withdrawn from the respective socket-like member 27 with the rotating scraper blades then cleaning that pipe end and eliminating any ovality. Continued opposite movement of the clamp 6 withdraws the rods 21 through the support 25 until the collars at the ends of the rods abut the support, from which point the scraper attachment 24 is caused to be pulled away from the clamp 25, progressively pulling the rotating socket-like member 27 to that side from the pipe end in the clamp 6, again to clean that pipe end and eliminate any ovality.

The pipe ends are now in a condition to receive a connecting sleeve such as for exmaple an electrofusion 25connecting sleeve, and whereby the pipe ends can be secured together.

Claims

1. A pipe clamp comprising first and second clamp means each pivotally mounted on a support member, drive means extending between each said support member and its respective clamp member, a pivotal connection between each drive means and its respective clamp means and at least one of said clamp means and its associated support member being movable with respect to said other of said clamp means and associated support member.

2. A pipe clamp as in Claim 1, wherein the drive means is a threaded rod extending through a threaded hole to one side of the support member with a ball connection to engage a socket attached to the clamp.

3. A pipe clamp as in Claim 2, wherein the drive means extending between the respective support member and clamp means is a threaded rod extending through a threaded hole to one side of the respective support member, with a drive nut to one end of the threaded rod and a ball connection at the opposite end to engage a socket connected to the respective clamp such as by way of an actuator plate attached to the clamp means to which a socket to receive the ball is secured.

4. A pipe clamp as in any of Claims 1 to 3, wherein the support member and respective clamps are so mounted that at least one support member and clamp is movable with respect to the other support member and clamp.

5. A pipe clamp as in Claim 4, wherein one support member and its clamp is secured to the end of at least one double-acting piston and cylinder unit and the other support member and its clamp secured against movement and secured to the opposite end of the piston and cylinder unit, and whereby activation of the at least one piston and cylinder unit causes a relative movement of the clamps and pipe ends towards and away from each other.

6. A pipe clamp as in Claim 5, wherein for added stability, one or more additional guide rods are provided adjacent the at least one piston and cylinder unit.

7. A pipe clamp as in any of Claims 1 to 6, wherein for ease of transport the pipe clamp is mounted on a sled.

8. A pipe clamp as in Claim 7, wherein at least one support wheel is mounted on the sled at one end.

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9. A pipe clamp comprising first and second clamp means, a means of causing a respective movement of at least one clamp means with respect to the other, a scraper attachment located between said clamp means and adapted for movement with respect to said clamp means, there being at least two oppositely directed scrapers on the scraper attachment and mounted for rotation about the axis of the clamp means, and a drive means to cause said rotation of said scrapers.

10. A pipe clamp as in Claim 9, wherein the clamp means are on supports attached to at least one double-acting piston and cylinder, with adjacent stabiliser slide bars, the scraper attachment being mounted on a support block slidably located on the slide bars and to which the scraper attachment is detachably secured.

11. A pipe clamp as in Claim 10, wherein the support block is freely slidable on the slide bars and movable thereon by contact with one of the pipe ends associated with one of the clamps.

12. A pipe clamp as in Claim 10, wherein the support for the scraper attachment is pivotally mounted on a Zlinkage the free ends of which are attached respectively to the clamps and whereby a movement of one clamp towards the other causes a commensurate simultaneous movement of the scraper attachment towards that other clamp.

13. A pipe clamp as in Claim 10, wherein spring means are associated with the support for the scraper attachment, the ratings of which are selected such that a force applied to the support caused by movement of one clamp causes an equal and one-half rate movement of the support towards the other clamp.

14. A pipe clamp as in any of Claims 9 to 13, wherein the oppositely directed scrapers are movable between a retracted position and an operative position, and there being a release means capable of contact by a pipe end to cause the movement of the scrapers to the operative position when the pipe ends have been properly presented to the scraper attachment.

15. A pipe clamp substantially as hereinbefore described with reference to the accompanying drawings.