GB2431607A

GB2431607A - Pipe cutter with retractable cutting tip

Info

Publication number: GB2431607A
Application number: GB0521802A
Authority: GB
Inventors: Roger Alfred Bullivant
Original assignee: Roxbury Ltd
Current assignee: Roxbury Ltd
Priority date: 2005-10-26
Filing date: 2005-10-26
Publication date: 2007-05-02
Also published as: GB0521802D0

Abstract

The cutter includes at least one cutting tip 68 and releasable means for holding 20 the apparatus in place. Each culling tip 68 can be selectively advanced or retracted by a deployment arrangement 22 located outside the tube. Preferably the holding means 20 include a resilient ring 50 that is deformed when it is pressed between screw clamps 44A, 44B. Preferably each cutting tip 68 is pivoted 64 into position or moved by a cam 72. Preferably the tips are steel, tungsten carbide or diamond. The cutter forms holes in a bore 12 wall 18 from the inside.

Description

I

Cutter Arrangements The present invention relates to cutter arrangements.

Various situations exist in which it is required to cut tubes, pipes and the like to length.

The present invention provides a cutter arrangement for introduction into a bore for cutting the wall of the bore from within, comprising: at least one cutter member having a retracted position and an advanced position for engaging the bore wall; a holding arrangement releasably operable from outside the bore to set the position of the cutter member or members along the bore; and a deployment arrangement operable from outside the bore to selectively advance and retract the or each cutter member, and to turn the cutter member or members to cut the bore wall.

Preferably the holding arrangement is operable to press generally transversely against the wall of the bore, to hold the arrangement at a chosen position along the bore. The holding arrangement may include a resilient member and means for squeezing the resilient member in a generally longitudinal direction, to cause the resilient member to expand transversely into engagement with the bore wall. The squeezing means may include clamp members between which the resilient member is positioned, and a clamp arrangement to force the clamp members together. The clamp arrangement may comprise a threaded member engaging at least one of the clamp members to cause clamping by rotation of the threaded member relative to the engaged clamp member. The threaded member is preferably an elongate member which extends out from the bore to allow the clamp arrangement to be operated from outside the bore.

The or each cutter member is preferably mounted to pivot between the retracted and advanced positions. The or each cutter member may comprise a shank extending from the pivot to a cutting tip.

The deployment arrangement preferably includes cam means operable to move the or each cutter member. The deployment arrangement may include a first body on which the or a cutter member is mounted, a second body having a cam surface for engaging the cutter member, and an actuator arrangement operable to cause relative movement between the bodies, thereby causing the cam surface and cutter member to cooperate to create movement of the cutter member. The deployment arrangement may comprise an elongate deployment member attached to one of the bodies to extend out of the bore for moving the said one of the bodies relative to the other. The deployment arrangement may comprise a return spring against which the said one of the bodies moves. The return spring preferably acts between the bodies.

The deployment member may be in threaded cooperation with another member to cause relative movement and thereby to move the said one of the bodies. The said another member is preferably releasably held in position relative to the cutting position. The said another member may be the threaded member of the clamp arrangement defined above.

Examples of the present invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which: Fig. I is a section at a plane transverse to the axis of a cutter arrangement of the present invention and a pipe being cut; and Fig. 2 is an enlarged view of the cutting head of the arrangement of Fig. 1.

The drawings show a cutter arrangement 10 after introduction into the bore 12 of a pipe 14. The arrangement 10 is operable, as will be described, to cut the pipe 14.

The arrangement 10 comprises cutter members 16 which have a retracted position (Fig. 1) and can move to an advanced position (as will be described) for engaging the wall 18 of the bore 12. A holding arrangement illustrated generally at 20 is releasably operable from outside the bore, generally at 22, to set the position of the cutter members 16 along the bore 12. A deployment arrangement, indicated generally at 24, is operable from outside the bore, generally at 22, to selectively advance and retract the cutter members 16 and to turn the cutter members 16 to cut the bore wall 18.

In the detailed description to follow, the cutter arrangement 10 will be described in use for cutting a metal pipe driven generally downwardly into the ground, such as for piling purposes. Consequently, primarily for reasons of convenience, the description will refer to the relative positions of components in this context, referring to terms such as "above", "below" etc. However, it is to be understood that the use of the embodiment being described, and the invention, are not limited by reference to any particular orientation. For example, it is envisaged that the arrangement 10 could be introduced generally horizontally into ground pipes (such as gas pipes, water pipes or other services) to allow the pipes to be cut for removal or repair. Furthermore, the single term "pipe" is used for brevity, but is intended also to cover tubes and other equivalent forms.

In more detail, the cutter arrangement consists generally of a head 30 mounted at the end of a generally elongate region 32, so that the head 30 can be introduced into the pipe 14, with the elongate portion 32 extending back out from the bore 12 to the region 22. This allows the functions of the head to be controlled from the region 22, as will be described.

The elongate portion 32 has two principal components, namely an inner elongate member 34 and an outer elongate member 36. The inner member 34 is formed in this example as a tube 38 having short externally threaded shafts 40, 42 fixed in the upper and lower mouths of the tube 38.

Alternatively, the inner member 34 could be formed as a single externally threaded component.

The outer member 36 is a tube within which the inner member 34 is received. The upper shaft 40 extends out of the upper mouth of the tube 36.

The lower shaft 42 extends out of the lower mouth of the tube 36.

Hold inQ Arranciement The holding arrangement 20 includes upper and lower clamp members 44A, 44B through which the shaft 42 extends. The upper clamp member 44 houses an "0" ring, spring clip or the like 46 to engage lightly in a circumferential groove 48 around the shaft 42, allowing the shaft 42 to turn relative to the clamp member 44A, but resisting axial movement of the clamp member 44A along the shaft 42.

The lower clamp member 44B is close to the end of the shaft 42 and is internally threaded to engage the thread of the shaft 42. Accordingly, relative rotation of the shaft 42 and the clamp member 44B causes the clamp member 44B to move axially along the shaft 42.

A resilient body 50 is provided between the clamp members 44A, B. In this example, the resilient body 50 is a ring of resilient material, such as hard rubber. The body 50 is backed by a supporting ring 52.

The arrangements which have just been described allow the head 30 to be releasably secured in position at the required position in the bore 12, as follows.

After introducing the head 30 into the bore 12, the inner member 34 is turned about its axis. This may be done by engaging the inner member 34 in the region 22. Preferably, the upper end of the shaft 40 is formed for cooperation with a spanner or other tool. Rotation of the member 34 creates rotation of the lower shaft 42 relative to the clamp member 44B. The clamp member is held gently against rotation, by friction between the body 50 and the bore wall 18. Accordingly, the clamp member 44B can be drawn up the shaft 42 toward the upper clamp member 44A, which is held against axial movement by the spring clip 46. As the clamp members 44A, B approach each other, the body 50 is squeezed between the lips 47 of the members 44a, 44B. This causes the body 50 to bulge outwardly, transversely toward the bore wall 18. This outward bulging is further encouraged by the presence of the supporting ring 52, which tends to resist inward bulging toward the shaft 42.

It is envisaged that a relatively small clamping movement of this nature will be sufficient in practice to create a significant outward force on the bore wall 18, sufficient to hold the head 30 at the chosen position, while the pipe 14 is cut, as can now be described. Furthermore, it is envisaged that light friction will initially allow this clamping process to begin, which will become increasingly strong, holding the body 50 and clamp member 44B against rotation.

Deployment Arrangement The lower end of the outer member 36 carries a first body 54 attached to the member 36 by means of a flange 56 and bolts 58. The inner member 34 extends through a bore 60 in the body 54, with a bush 62 being provided to ensure freedom for relative rotation between the inner member 34 and the first body 54.

The cutter members 16 are mounted on the first body 54 at pivots 64.

Each cutter member 16 has a shank 66 which extends away from the pivot 64 to a cutting tip 68, which may be formed of a cutting medium such as high speed steel, tungsten carbide, diamond or the like. Each cutter member is received partly in a radially extending slot in the first body 54. In the retracted position of the cutter member 16, the cutter member 16 extends generally parallel to the axis of the bore 12. The pivot 64 allows the cutter member 16 to pivot to advance the tip 68 out to the bore wall 18. Thus, the tip 68 may move generally in the directions indicated by the double-headed arrow 70 in Fig. 1.

Movement of the cutter members 16 is controlled in part by a generally conical cam face 72, formed in this example on the upper face of the upper clamp member 44A, which faces the first body 54. Thus, the upper region of the clamp member 44A is also serving as a second body 74 within the deployment arrangement for controlling the cutter members 16.

A helical compression spring 76 is provided between the first body 54 and the second body 74, to urge the bodies apart. An 0 ring, resilient ring or other resilient member 78 is provided around the cutter members 16, tending to withdraw the cutter members 16 from the bore wall 18, to their retracted position.

Consideration of Fig. 2 reveals that when the holding arrangement 20 has been operated to hold the head 30 at the required position in the bore 12, the inner member 34 and the clamp members 44A, B are fixed in position along the bore 12. However, the outer member 36 can move along the bore 12. Thus, the outer member 36 can be moved to press the first body 54 toward the second body 74, against the action of the spring 76. As this happens, the cutter members 16 engage the cam face 72 and are deflected on their pivots 64, to extend the tips 68 out into engagement with the bore wall 18.

This axial movement of the outer member 36 is preferably achieved by a threaded collar 80 having radially extending handles 82 and an internally threaded bore at 84, cooperating with the external thread of the shaft 40.

Thus, the collar 80 can be turned to move along the shaft 40 until engaging the upper end of the outer member 36. Further rotation of the collar 80 then presses the outer member 36 down over the inner member 34, to deploy the cutter members 16, as described.

The collar 80 is left in this position, to hold the cutter members 60 deployed in their advanced positions.

Cutting Rotation of the outer member 36 about the axis of the bore 12 thereafter allows the first body 54 to be turned, causing the cutter members 16 to turn and score the bore wall 18 by the tips 68, until the pipe 14 is cut. In this example, this turning is achieved by a further collar 86 and handle 88.

The collar and handle 86, 88 preferably incorporate a ratchet mechanism allowing convenient use to turn the cutter members 16 against the reaction caused by the cutting action.

It is desirable for the outer member 36 to carry a third collar 90 to help retain the member 36 centrally in the bore 12, particularly if the arrangement lOis very long.

Accordingly, it can be understood from the above description that the sequence of operations for using the apparatus described, in the manner described, can be summarised as follows: 1. Introduce the head 30 into the pipe 14, to place the cutters 16 at the required cutting position along the bore, with the members 34, 36 projecting out of the bore.

2. Turn the inner member 34 to clamp the resilient body 50, causing it to bulge and secure the head 30 in position within the bore 12.

3. Turn the collar 80 to drive the outer member 36 down, causing the cam face 72 to move the cutter members 16 to their advanced position, with the tips 68 engaging the bore wall 18.

4. Turn the outer member 36 by means of the collar 86 and handle 88, causing the cutter members 16 to score and cut around the bore wall 18.

5. Release the collar 80 once the cut has been completed, to allow the cutter members 16 to move back to their retracted position under the influence of the 0 ring 78.

6. Release the resilient body 50 by turning the inner member 34.

7. Remove the head from the pipe 14.

8. Remove the cut length of pipe.

This sequence is simple to execute and is considered particularly advantageous in allowing all operations to be executed by manipulation of the arrangement 10 in the region 22. Thus, a pipe 14 may be cut internally by manual use of the arrangement 10 at a convenient access position at the end of the pipe 14, even if access to the pipe is not possible at the required cutting position.

It will be apparent that many variations and modifications to the example described above can be made without departing from the scope of the present invention. In particular, the shapes, sizes, forms and materials used for the various components could be modified in many different ways which will be readily apparent to the skilled reader with a full understanding of

the disclosure set out above.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS

1. A cutter arrangement for introduction into a bore for cuthng the wall of the bore from within, comprising: at least one cutter member having a retracted position and an advanced position for engaging the bore wall; a holding arrangement releasably operable from outsIde the bore to set the position of the cutter member or members along the bore; and a deployment arrangement operable from outside the bore to selectively advance and retract the or each cutter member, and to turn the cutter member or members to cut the bore walL
2. A cutter arrangement according to claim 1, wherein the holding ---arrangement is operable to press generally transversely against the wall of the bore1 to hold the arrangement at a chosen position along the bore.

3. A cutter arrangement according to claim 2, wherein the holding -. -arrangement includes a resilient member and means for squeezing the ---resilient member in a generally longitudinal directIons to cause the resilient member to expand transversely into engagement with the bore wall.

4. A cutter arrangement according to claim 3, wherein the squeezing means includes clamp members between which the resilient member Is positioned, and a clamp arrangement to force the clamp members together.

5.. A cutter arrangement according to claim 4, whereIn the clamp arrangement comprises a threaded member engaging at least one of the clamp members to cause clamping by rotation of the threaded member relative to the engaged clamp member.

6. A cutter arrangement according to claim 5, wherein the threaded member is an elongate member which extends out from the bore to allow the clamp arrangement to be operated from outside the bore.

7 A cutter arrangement according to any preceding claim, wherein the or each cutter member is mounted to pivot between the retracted and advanced positionS.

8. A cutter arrangement according to claim 7, wherein the or each cutter member comprises a shank extending from the pIvot to a cutting tip.

9. A cutter arrangement according to any preceding claim, wherein the deployment arrangement includes cam means operable to move the or each cutter member. .. --.

10. A cutter arrangement according to claim 9, wherein the deployment arrangement includes a first body on which the or a cutter member is mounted, a second body having a cam surface for engaging the cutter member, and an actuator arrangement operable to cause relative movement between the bodies1 thereby causing the cam surface and cutter member to --cooperate to create movement of the cutter member.

11. A cutter arrangement according to claim 10. whereIn the deployment arrangement comprises an elongate deployment member attached to one of the bodies to extend out of the bore for moving the said one of the bodies relative to the other.

12. A cutter arrangement according to claim 11, wherein the deployment arrangement comprises a return spring against which the said one of the bodies moves.

13. A cutter arrangement according to claim 12, wherein the return spring acts between the bodies.

14. A cutter arrangement according to any of claims 10 to 13, wherein the deployment member is in threaded cooperation with another member to cause re'atiVe movement and thereby to move the said one of the bodies.

15. A cutter arrangement according to claim 14, wherein the said another member is releasably held In position relative to the cutting position.

16. A cutter arrangement according to claims 14 or 15, insofar as dependent Ofl claims 5 or 6, wherein the said another member is the threaded member of the clamp arrangement.

17. A cutter arrangement substantially as described above, wfth reference ---- to the acompaflyiflg drawings. --ie. Any novel subject matter or combination including novel subject matter disclosed herein1 whether or not within the scope of or relating to the same * -invention as any of the preceding claims.