GB2249774A - Pipe clamping device, and use thereof - Google Patents

Abstract

The pipe clamp (10, 13) is linked to a hydraulic bucket actuating mechanism (6) at the end of an arm (1) of a mechanical digger. The clamp comprises two opposed concave gripper members which are operated by the bucket- actuating mechanism to selectively grip or release a pipe (P). When gripped the pipe may be moved longitudinally of itself by means of movement of the arm of the mechanical digger. Preferably the lower clamp member is supported in a framework (11, 12). <IMAGE>

Description

Pipe Clamping Device. and use thereof This invention relates to pipe clamping devices, and the use thereof in a method of inserting a pipe along a passage.

Re-laying a pipeline is a complicated, disruptive and expensive business. For total replacement of the pipeline, the ground has to be dug up along the entire length of the pipe, the old one lifted out, the new one laid, and the trench back-filled.

This is avoidable in certain circumstances, and a technique has been developed of threading an existing pipeline with new, smaller bore piping. With modern materials, higher pressures can be sustained in the new pipeline and therefore the same capacity can be achieved despite the reduction of size. Of course, the existing pipeline has to be broken into at intervals for the new piping to be inserted and pushed in, and also to be extracted or joined up at the other end.

A dedicated machine has been developed for pushing such new piping into existing underground pipelines, but it is quite large, requiring a correspondingly large excavation to enable it to be set into alignment with the existing pipewort. It is also timeconsuming to set up and dismantle, and very expensive.

It is the aim of this invention to provide a much simpler, cheaper and more compact device which will carry out the same job much more quickly and easily, using a mechanical digger of a kind which is almost invariably on site to excavate the ground down to the existing pipework and which would otherwise be standing idle while insertion was carried out.

According to a first aspect of the invention, there is provided a pipe clamping device comprising at least two clamping members arranged to be selectively movable relative to one another such that a pipe may be clamped therebetween, said device being provided with connection means for connecting to respective parts of a bucket actuating mechanism at the end of an arm of a mechanical digger, whereby selective actuation of said mechanism causes relative movement of said clamping members.

Since the bucket actuating mechanism, and hence relative movement of the gripper members, is generally hydraulically actuated, the clamping members are movable to engage and grip various sizes of pipe.

It is preferred that a pair of clamping members are provided, each advantageously having an arcuately curved surface profile for gripping the cylindrical outer surface of a pipe. Typically therefore the clamping members have part cylindrical clamping surfaces arranged to engage and grip the pipe.

Advantageously, a lower clamping member is provided in a support cradle, the lower clamping member having a curved arcuate gripping surface on which the pipe may rest. In this embodiment it is preferred that the lower clamping member is fixed relative to the cradle with an upper clamping member being movable relative to both the cradle and lower clamping member. It is preferred that the support cradle is pivotally connected to the arm of the mechanical digger. It is further preferred that the upper clamping member is constrained to move in a defined manner relative to the cradle by means of guide members provided on the cradle.

In use, a pipe is gripped by the device and the arm of the digger is moved to shift the gripped pipe longitudinally. The pipe is then released, the arm is moved in the opposite direction with the clamp sliding freely along the pipe, and then the pipe is regripped, and so on. Thus the pipe can be shifted lengthwise step by step (i.e.

incrementally).

According to a second aspect of the invention, therefore, there is provided a method of incrementally inserting an elongate pipe along a passage, which method comprises clamping a portion of said pipe between at least two hydraulically actuated clamping members connected to the arm of a mechanical digger, moving said arm such that a length of said pipe is fed along said passage, releasing said clamping members, and retracting said arm such that the arm moves relative to the pipe in the longitudinal direction of the pipe.

Typically the passage will be a pre-existing pipe or conduit below ground surface.

The clamping device used in the method according to the invention is, of course, typically as described above with reference to the first aspect of the invention.

For a better understanding of the invention, one embodiment will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 is a side view of the pipe clamp mounted at the end of a boom of a mechanical digger, and Figure 2 is an end view of the clamp of Figure 1.

A mechanical digger has an articulated boom of which the end of the arm 1 at the extremity is shown. A rocker 2 is pivoted on this arm by a transverse pin 3 and can be swung as indicated by the double arrow by a hydraulic ram 4 generally parallel to the arm 1, anchored at its other end and acting on a pin 5 parallel to the pin 4. From the upper pin 5 there are suspended links 6. In normal use, a bucket is attached by parallel pins through the end of the arm 1 and through the lower ends of the links 6, and its scooping action is governed by the ram 3 and by movement of the arm 1, which is also hydraulically actuated.

The cable clamp has a square U-shaped body 7 and within it, over its web 8, there is a cradle 9. This has a semi-cylindrical portion 10, open at both ends, resting on the web 8 and laterally supported by flanges 11 extending out to the sides of the body 7.

Extending upwardly from these flanges are guide members 12 which laterally confine a semicylindrical element 13 matching the portion 10. It is concave downwards and so in its lowermost position it defines with the portion 10 a substantially circular section passage 14 through the body 7.

The element 13 is carried by a transverse pin 15 extending through holes in the upper ends of upstanding lugs 16, through the ends of the links 6 and through slots 17 in the sides of the body 7. The pin is secured by quick release fastenings 18 on the outside of the body 7. The slots 17 extend generally vertically, assuming the web 8 to be horizontal, but it may be found advantageous to have them at an angle. In any event, they permit up and down movement of the element 13 relative to the cradle 9 so that the passage 14 can be enlarged or reduced by actuation of the ram 3. The arm 1 is also coupled to the body 7 by a transverse pin 19 held by fastenings 20, but this is a close fit in holes in the sides, and will only allow pivoting.

For use, the body 7 is positioned so that a pipe P rests in the cradle 9. The arm 1 is then moved to shift the body 7, and hence the pipe P, longitudinally. Usually, this movement will be a withdrawing action of the arm towards the main body of the digger.

The ram 3 is then retracted to release the clamping action, the arm 1 is extended again, and the device with a widened passage 14 slides freely along the pipe P. Clamping is then applied again and the action repeated.

The cradle 9 and element 13 may be replaceable, to cater for pipes of different diameter, or they may be equipped with inserts, to reduce the size of the passage 14.

It will be noticed that, during operation, no-one has to be in the excavation, which is a substantial safety advantage.

Claims (8)

CLAIMS:

1. A pipe clamping device comprising at least two clamping members arranged to be selectively movable relative to one another such that a pipe may be clamped therebetween, said device being provided with connection means for connecting to respective parts of a bucket-actuating mechanism at the end of an arm of a mechanical digger, whereby selective actuation of said mechanism causes relative movement of said clamping members.

2. A pipe clamping device according to claim 1, wherein a pair of clamping members is provided, each clamping member having an arcuately curved surface profile for gripping the cylindrical outer surface of a pipe.

3. A pipe clamping device according to claim 1 or 2, wherein the clamping members have part cylindrical clamping surfaces arranged to engage and grip the pipe.

4. A pipe clamping device according to any preceding claim, wherein a lower clamping member is provided in a support cradle, the lower clamping member having a curved arcuate gripping surface on which the pipe may rest.

5. A pipe clamping device according to claim 4, wherein the lower clamping member is fixed relative to the cradle and an upper clamping member is movable relative to both the cradle and lower clamping member.

6. A pipe clamping device according to claim 5, wherein the upper clamping member is constrained to move in a defined manner relative to the cradle by means of guide members provided on the cradle.

7. A pipe clamping device according to any of claims 4 to 6, wherein the support cradle is pivotally connected to the arm of a mechanical digger.

7. A pipe clamping device according to any of claims 4 to 6, wherein the support cradle is pivotally connected to the arm of a mechanical digger.

8. A pipe clamping device substantially as herein described with reference to the accompanying drawings.

9. A method of incrementally inserting an elongate pipe along a passage, which method comprises gripping a portion of said pipe between at least two hydraulically actuated gripper members connected to the arm of a mechanical digger, moving said arm such that a length of said pipe is fed along said passage releasing said gripper members and retracting said arm such that the arm moves relative to the pipe in the longitudinal direction of the pipe.

10. A method according to claim 9, wherein said portion is gripped by means of a clamping device according to any of claims 1 to

8.

AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS CLA#IS: 1. A pipe clamping device comprising at least two clamping members arranged to be selectively movable relative to one another to clamp a pipe, said device being provided with connection means for connecting to respective parts of a bucket actuating mechanism at the end of an arm of a mechanical digger, whereby selective actuation of said mechanism causes relative movement of said clamping members, such that said pipe may be clamped thereby between having its longitudinal direction substantially in the direction of movement of said arm of said mechanical digger.

2. A pipe clamping device according to claim 1, wherein a pair of clamping members is provided, each clamping member having an arcuately curved surface profile for gripping the cylindrical outer surface of a pipe.

3. A pipe clamping device according to claim 1 or 2, wherein the clamping members have part cylindrical clamping surfaces arranged to engage and grip the pipe.

4. A pipe clamping device according to any preceding claim, wherein a lower clamping member is provided in a support cradle, the lower clamping member having a curved arcuate gripping surface on which the pipe may rest.

5. A pipe clamping device according to claim 4, wherein the lower clamping member is fixed relative to the cradle and an upper clamping member is movable relative to both the cradle and lower clamping member.

6. A pipe clamping device according to claim 5, wherein the upper clamping member is constrained to move in a defined manner relative to the cradle by means of guide members provided on the cradle.