WO2010043861A2

WO2010043861A2 - Compression ring removal tool

Info

Publication number: WO2010043861A2
Application number: PCT/GB2009/002459
Authority: WO
Inventors: Jeff Gilbey
Original assignee: Scottool Limited
Priority date: 2008-10-13
Filing date: 2009-10-13
Publication date: 2010-04-22
Also published as: GB2464325A; WO2010043861A3; GB2464325B; GB0818751D0

Abstract

A tool (2) for removing a compression ring from a pipe comprises means for controllably moving a cutting part in use generally radially with respect to a pipe and into engagement with a compression ring thereon. The cutting part (8) comprises a cutter (16) for cutting into the ring and a stop (18) for preventing the cutter from cutting into the pipe. The cutting part may be mounted or coupled to a threaded spindle (20) which is rotatable in a threaded bore of the tool body. A solid anvil part (6) may be engageable inside a pipe in use of the tool (2).

Description

INDICATOR DEVICE FOR FOREARM

The present invention relates to a compression ring removal tool.

In the field of plumbing, a common method of attaching and sealing a first pipe to a second pipe or other member is to employ a compression fitting comprising a compression nut and a compression ring (often referred to as an Olive¹). The compression ring is typically made of a deformable material such as copper or brass. After the compression nut is placed onto the pipe, the closely fitting compression ring is pushed down onto the pipe, and then the member requiring attachment, e.g. a valve, is placed onto the pipe and threaded into the compression nut. As the compression nut is screwed up onto the valve or other member, it compresses the ring radially inwardly so as to create both a mechanical grip onto the pipe and a fluid-tight seal. Such a compression fitting is commonly used in domestic plumbing to connect a water pipe to a radiator valve.

Compression fittings are often used where a non-permanent pipe connection is required, for example where the connected member such as a radiator valve will be removed from time to time for maintenance or replacement. When reconnecting a valve or other member to a pipe by means of a compression fitting, it is, important to remove the old compression ring and replace it with a new one to ensure proper sealing upon reconnection. Compression rings may also need to be removed and replaced if they wear out and the connection starts to leak.

Due to the gripping attachment of the compression ring to the pipe it is difficult to remove the ring without damaging the underlying the pipe. This problem is exacerbated as domestic water pipes are typically formed of thin- walled copper tubing. One traditional method for removing a compression ring from a pipe involves sawing through the ring to release it, but this method is difficult to control and often results in damage to the pipe.

Instead a plumber may simply cut off the top of the pipe with the compression ring attached and reconnect a compression fitting to the newly exposed pipe. This involves unnecessary waste and is not always possible, e.g. depending on the length of pipe left available for connection. Replacement of the pipe may be required.

Several tools have been proposed for helping to remove a compression ring from a pipe. A tool called an 'olive puller¹ is known and is generally described in GB- 2384456. This tool aims to remove a compression ring or Olive' in a non-destructive manner. The valve or other member is removed from the pipe but the compression fitting is left in place with the nut tightened over the olive. The body of the tool is threaded into the compression nut and a threaded plunger engages into the pipe. Using a spanner to hold the body of the tool against rotation, the plunger is wound down into the body of the tool. This results in the compression nut and ring being pulled from the end of the pipe.

Although the 'olive puller' tool does not destroy the compression ring, it can still cause damage to the pipe. The ring is gripped so tightly onto the pipe that forcibly pulling it off the pipe can cause scratching, scarring and deformation of the pipe. Such damage may interfere with the proper fitting and sealing of a new compression ring, and can only be rectified by removing the damaged pipe section and connecting to a new pipe section instead.

Tools have also been proposed which attempt to cut the compression ring from the pipe in a more controlled manner than using a handsaw. One such tool known as an 'olive cutter' is similar to pliers and comprises a pair of cutting blades which slice into the olive when the handles are squeezed together. However, use of such a tool can readily result in damage to the pipe when at least one of the blades cuts through the olive and into the pipe before a user has chance to release the torque applied. The force is often applied unevenly between the two blades, resulting in damage to one side of the pipe before the blade on the other side has penetrated the ring.

Furthermore the geometry of such an 'olive cutter' is dictated by the size of the olive to be cut, and thus a separate tool is required for different size olives e.g. corresponding to standard copper pipe diameters of 8, 10, 15, 22 and 28 mm. It is not practical for a plumber to carry a number of different versions of the same bulky tool for just one small job.

It is an object of the present invention to provide an improved tool and according to a first aspect of the invention there is provided a tool for removing a compression ring from a pipe comprising means for controllably moving a cutting part in use generally radially with respect to a pipe and into engagement with a compression ring thereon, said cutting part comprising a cutter for cutting into the ring and a stop for preventing the cutter from cutting into the pipe.

Thus in accordance with the invention the tool is provided with a stop to limit movement of the cutting part radially inward of the compression ring i.e. into the pipe. This means that the ring can be controllably broken without damaging the pipe, allowing the ring to be efficiently removed and replaced.

The stop may be provided at any suitable location on the cutting part. Preferably the cutter and stop are integrally formed in the cutting part. This can be achieved by providing a sharp edge to form the cutter and a blunt edge to form the stop. In order that the stop does not interfere with cutting of the compression ring, the cutting part is preferably dimensioned such that only the cutter will contact a compression ring in use. In other words, the cutter is at least as wide as a compression ring and/or the stop is arranged to contact a pipe outside of the compression ring. This is easily achieved as standard compression rings come in a limited number of sizes (typically nominal diameters of 15 mm, 22 mm and 28 mm, possibly also imperial /2", %", and 1" to match standard pipe sizes). For example, a standard compression ring of nominal diameter 15 mm is 6 mm wide whereas a standard compression ring of - A -

nominal diameter 22 or 28 mm is 8 mm wide. Accordingly it is preferred that the cutter is at least 8 mm wide and preferably around 10 mm wide so that the tool can be used to remove any size of compression ring. A wider cutter may be employed if desired. Although less preferred, a more compact cutter may be provided where the tool is intended for use only with pipes of a certain size e.g. 15 mm diameter copper piping. It is a notable advantage of the tool that in at least preferred embodiments it is capable of cutting a compression ring of any size. A plumber therefore need only to carry a single tool which will work in any situation.

The stop, for example a blunt edge, is preferably provided to the side of the cutter. Due to the width of the cutter preferably being at least as large as the width of the compression ring, the stop will not come into contact with the compression ring. Once the cutter has been forced into or through the ring, however, the stop will come up against the outer surface of the pipe radially inward of the ring. The stop may be provided either above or below the cutter, so as to contact the pipe either above or below the ring, but it is preferred that there is a stop either side of the cutter. Such a symmetrical arrangement of helps to ensure that the cutting part comes to a standstill as soon as it reaches the pipe and even if there is a turning moment applied to the cutting part, the cutter will not penetrate into the pipe.

The cutter may be formed by one or more suitable sharp edges. In a preferred set of embodiments the cutter comprises a single sharp edge. The edge may be wedge- shaped so as encourage the ring to split apart as the edge is driven into it.

Movement of the cutting part can be effected by any suitable means as long as at least the final stages of its movement are in a direction which is generally radial with respect to the pipe and compression ring. The movement may be linear or nonlinear. Non-linear, rotary movement of the cutting part can be arranged to bring the cutter into tangential contact with the ring and pipe. Thus in accordance with some less preferred embodiments the tool may comprise means for applying a torque resulting in rotary movement of the cutting part against the ring and pipe. In such embodiments the cutting part may be pivotally mounted and actuated by a rotatable handle. The tool could comprise a pair of pivotable arms with one arm providing an anvil part insertable into the pipe and the other arm providing the cutting part. However the movement in such tools is not easy to control and tends to be impulsive. Long handles may be required to provide sufficient torque and thus cutting force, but this can make the tool difficult to use in a typical plumbing environment involving tight spaces and adjacent obstacles such as pipes, walls and radiators.

Moreover when the cutting part is rotated into contact with the compression ring and pipe it is not easy to ensure that the cutting surface contacts the ring evenly so as to sever it fully across its width. It is therefore preferable that the cutter is moved linearly in a direction radial to the pipe and ring, thereby ensuring that all of the cutter's force is transmitted straight through the ring rather than being wasted as a component tending to push the ring up or down the pipe. Such axial force is unwanted as it may force the ring up or down the pipe during the removal operation and cause scratching or other damage to the pipe. It is therefore preferred that the tool comprises means for controllably moving the cutting part linearly in a direction which is radial to the pipe and ring.

It is envisaged that in at least some embodiments the tool may comprise means for applying a linear force to effect linear movement of the cutter. The cutting part could, for example, be provided at the end of a plunger that is pushed in use towards the ring and pipe. A ratchet mechanism could be used to provide incremental forward movement of the plunger, although a release mechanism would be required to allow for retraction of the cutter. In accordance with a preferred set of embodiments the tool comprises means for applying a torque and means for converting the applied torque into a linear force effecting movement of the cutter. This is preferred as it is easier in manual operation to apply a turning force than a linear force. Increasing the distance between the turning point and the point of application provides a straightforward way of increasing the magnitude of the force. Of course, a combination of linear and turning forces may be applied to give the resultant movement. In many domestic plumbing situations requiring removal of a compression ring from a pipe, the working space available around the pipe is limited by the presence of other components of the plumbing system as well as by nearby floors and walls. The next nearest component in the plumbing system, for example a radiator, will typically be located at a short axial distance from the pipe to which it is to be connected by a compression fitting. Pipe bends are generally avoided wherever possible. Thus there is often more space available laterally of the pipe. For this additional reason it is advantageous for the tool to move the cutting part linearly in a direction radial from the pipe, i.e. utilising the side space around the circumference of the pipe to apply a torque.

Thus in accordance with a second aspect of the invention there is provided a tool for removing a compression ring from a pipe comprising a cutting part, means for applying a torque, and means for converting the applied torque into controlled linear movement of the cutting part generally radially with respect to a pipe and into engagement with a compression ring thereon.

A more compact tool is thereby achieved which can generate the same cutting force while requiring the minimum amount of space to work the tool.

According to this aspect of the invention a stop is not necessarily provided. By using a torque handle or similar to generate the required linear cutting force, it is easier to manually control the force being applied. Thus a user can turn the torque handle, or other torque applying means, slowly and steadily while watching the linear movement of the cutter. As the cutter moves radially into contact first with the compression ring on the outside of the pipe, a user can carefully apply enough force to cut through the ring but without moving the cutter past the ring and into the pipe. It is therefore an advantageous arrangement even without a stop, but it will be appreciated that the tool is made safer and can be operated with less skill when a there is also provided a stop for preventing the cutter from cutting into the pipe as in the first aspect of the invention. The preferred features described hereinabove therefore apply equally to the invention in its second aspect.

Where an applied torque is converted into controlled linear movement of the cutting part, it is preferred that the movement can be incrementally controlled. As explained above, if no stop is present then this allows a user to control the movement of the cutting part precisely so as to cut through the compression ring but not into the pipe. It is also preferred that both forwards and backwards movement of the cutting part is possible using the same mechanism. The torque could be applied to a cam which progressively pushes the cutting part forwards as it rotates. However a simple and effective way of smoothly converting torque into linear motion (in both directions) utilises a screw. Thus in accordance with a preferred set of embodiments the cutting part is mounted or coupled to a threaded spindle which is rotatable in a threaded bore. The threaded bore may be formed in a body of the tool.

Preferably a torque handle or the like is attachable or attached to the opposite end of the spindle to the cutting part to facilitate rotation thereof. Additionally or alternatively, the spindle may provide for connection with a spanner or wrench to allow a torque to be applied thus. For example, a portion of the spindle may be shaped, e.g. like a nut, so as to be received in the mouth of spanner. An alien key arrangement could also be used, with a hexagonal recess in the opposite end of the spindle to the cutting part to facilitate rotation thereof with an alien key.

Some further preferred features in accordance with embodiments of both aspects of the invention will now be described.

The tool may simply be held radially outwardly of the pipe and ring and then deployed. However it is preferred that the tool further comprises means for engaging with the pipe such that it is easier for a user to hold the tool in a fixed position relative to the pipe. The tool may be provided with means for clamping onto the pipe so that no effort is required to steady the tool or hold it in place. As a typical water pipe made of copper tubing is relatively soft, there is a risk that the force of the part cutting through the ring and moving up against the pipe may cause the pipe to bend or otherwise deform. It is therefore preferred that there is further provided an anvil part engageable inside the pipe. The anvil part preferably contacts and supports the pipe radially inward of the cutting part on its path such that the force of the cutting part is transmitted through the pipe wall to the anvil. The anvil part is preferably engageable against the inside of the pipe wall opposite the ring section to be severed.

The anvil may be provided by a part separate from the tool, for example a handheld anvil, but in at least some preferred embodiments the anvil part is provided by the tool. In this way the anvil part can help to locate the tool relative to the pipe and ring, and help to steady the tool in use. Where the tool comprises a body, e.g. a body having a threaded bore as in some of the preferred embodiments described above, then the same tool body preferably forms an anvil part. In this way the number of tool parts is minimised. The tool body is advantageously a single unit which is manually engaged with the pipe and held stationary with one hand while the other hand applies the work necessary to move the cutting part relative to the body and towards the compression ring and pipe.

A still further aspect of the invention provides a compression ring removal tool comprising an anvil part shaped for insertion into the end of a pipe, the anvil part connected to a tool body which also mounts a compression ring cutting part which is movable with respect to the anvil part, and a threaded or ratchet actuating means operable to forcibly engage the cutting part against. a compression ring on a pipe end whilst engaged with the anvil part in use. This aspect of the invention may include any or all of the preferred features of the other aspects described above.

The invention also extends to improved methods for removing a compression ring from a pipe. In accordance with a further aspect of the invention there is provided a method of removing a compression ring from a pipe comprising providing a cutting part and controllably moving the cutting part generally radially with respect to a pipe having a compression ring thereon, said cutting part comprising a cutter for cutting into the ring and a stop for preventing the cutter from cutting into the pipe. In accordance with yet a further aspect of the invention there is provided a method of removing a compression ring from a pipe comprising providing a tool comprising a cutting part and applying a torque to the tool, the tool comprising means for converting the applied torque into controlled linear movement of the cutting part generally radially with respect to a pipe having a compression ring thereon. In accordance with yet a further aspect of the invention there is provided a method of removing a compression ring from a pipe comprising: providing a tool comprising a tool body, an anvil part connected to the tool body and a compression ring cutting part movably mounted to the tool body with respect to the anvil part; inserting the anvil part into the end of a pipe; and operating a threaded or ratchet actuating means to forcibly engage the cutting part against a compression ring on the pipe.

Although the tool has been described as facilitating removal of a compression ring from a pipe, it may of course find use in other situations and is not limited in its use.

Some preferred embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying Figures, in which:

Figure 1 is a perspective view of an olive removing tool in accordance with a preferred embodiment;

Figure 2 is a cross-sectional view of the tool of Figure 1 engaged into the end of a pipe in use; and

Figure 3 is a cross-sectional view of an olive removing tool in accordance with another preferred embodiment.

There is shown in Figure 1 an olive removal tool 2 generally comprising a body part 4, an anvil part 6, and a cutting part 8. The main parts of the tool 2 are machined from a low carbon mild steel designated as BS 970230M07 (ENlA) which is suitable for machining using automatic and CNC machines. The anvil part 6 projects from the body 4 with sufficient clearance to allow it to engage inside a pipe. The anvil part 6 is solid and generally cylindrical in shape with an outer diameter of no more than 13 mm to allow it to fit inside standard size copper pipes ranging in internal diameter from 15 to 32 mm. Although in this embodiment the anvil part 6 is fixedly connected to the body part 4, they could of course be integrally formed.

The cutting part 8 is arranged opposite to the anvil part 6 with a space between them large enough to accommodate a pipe and olive in use. As is seen more clearly from Figure 2, the cutting part 8 is slidably mounted in a cylindrical bore 10 in the tool body 4. The cutting part 8 is prevented from rotating in the bore 10 by a pin 12 extending radially between the cutting part 8 and the tool body 4. The pin 12 is accommodated in a cavity 14 in the tool body 4 which allows for translation of the pin 12 when the cutting part 8 moves axially in the bore 10. Abutment of the pin 12 against either end of the cavity 14 advantageously limits the movement of the cutting part 8 in and out of the bore 10. This can be arranged to provide a final stop against movement of the cutting part 8 such that it cannot be brought into contact with the anvil part 6 and accidentally blunted. However the pin 12 could be omitted and rotation of the cutting part 8 could instead be prevented by using a square section bore.

The fore end of the cutting part 8 comprises a cutting edge 16 and a pair of stops 18 arranged either side of the cutting edge 16. It will be seen from Figure 1 that the cutting edge 16 is formed by the apex of a wedge which extends back into the cutting part 8. The cutting edge 16 is parallel to the axis of the opposed anvil part 6. The stops 18 are formed by squared-off blunt portions arranged above and below the cutting edge 16 in the axial direction of the anvil part 6. When the tool 2 is engaged with a pipe 30 in use, as is shown in Figure 2, the axis of the anvil part 6 is aligned with the axis of the pipe 30. The length of the cutting edge 16 between the stops 18 is 10 mm. This ensures that the cutting edge is long enough for an olive of any size; at least in the UK olives normally come in nominal sizes of 15 mm, 22 mm and 28 mm, possibly also imperial VΪ \ %" and 1", to match standard pipe diameters and have a corresponding range of widths. For example, a standard compression ring of nominal diameter 15 mm is 6 mm wide whereas a standard compression ring of nominal diameter 22 or 28 mm is 8 mm wide. Of course the length of the cutting edge 16 can be adapted in a tool for use outside the UK where standard pipe and olive diameters may be different. The stops 18 are around 4-5 mm square. The area of the stops 18 is not critical as long as it is sufficient to bring the cutting part 8 to a standstill upon contact with a pipe 30.

The aft end 9 of the cutting part 8 is in the form of a connecting rod which is fixedly engaged with an actuating spindle 20. The spindle 20 has an external thread and engages within an internally threaded bore 22 formed in the tool body 4. The threaded bore 22 is an extension of the bore 10 in which the cutting part 8 moves. In this embodiment the spindle 20 is pushed onto the rod 9 of the cutting part 8 and secured by a resilient washer 21. The spring steel washer 21 is seated in a recess in the spindle 20 and grips onto the end, of the rod 9 so as to fixedly connect the two parts. When the spindle 20 is wound back, the washer 21 ensures that the cutting part 8 is pulled back together with the spindle 20.

The distal end 24 of the spindle 20 is arranged outside of the tool body 4 and is provided with a torque handle 26, commonly referred to as a "tommy bar" in the trade, to rotate the spindle 20 and screw it in and out of the bore 22. As the spindle 20 is wound in and out, it moves the associated cutting part 8 axially in and out of its own bore 10.

The torque handle 26 is slidably mounted in a transverse bore 28 passing through the distal end 24 of the spindle 20 so as to enable a torque to be applied from different sides. Stop portions 29 are provided at either end of the handle 26 to prevent it from sliding out of the bore 28. Of course a fixed handle may be used instead but will not allow as much flexibility in operation of the tool.

Operation of the tool to remove an olive 32 from a pipe 30 will now be described with reference to Figure 2. It will be seen that a compression fitting to the pipe 30 has been loosened by unscrewing the compression nut 34 and moving it down from the end of the pipe. An olive 32 remains grippingly attached to the end of the pipe 30. The tool 2 is engaged with the pipe 30 by inserting the anvil part 6 inside the pipe 30. The tool 2 is moved down until the cutting edge 16 is positioned radially outwardly of the olive 32. As the cutting edge 16 is wider than the olive 32, the stops 18 are necessarily disposed axially above and below the olive 32. The anvil 6 is pulled across into contact with an inner wall of the pipe 30 and held in position there. The tool 2 can be used at any circumferential position relative to the pipe 30, thus enabling it to be manoeuvred according to the lateral space available around the pipe 30, which may be limited in many situations.

The cutting part 8 is initially retracted relative to the tool body 4 so as to leave space for the pipe 30 and olive 32 to penetrate between the anvil part 6 and cutting part 8. Once the tool 2 is in position relative to the pipe 30 and olive 32, the torque handle 26 is turned to wind the spindle 20 into its bore 22. As the spindle 20 is screwed into the tool body 4, it pushes the cutting part 8 forward out of its bore 10 in a direction which is radially towards the pipe 30 and olive 32.

Turning of the handle 26 is continued until the cutting edge 16 contacts the olive 32 and application of further torque then causes the cutting edge 16 to penetrate into the olive 32. As the olive 32 will normally be made of brass or copper, it may split open as the cutting edge 16 is driven through. The handle 26 can be turned until the cutting edge 16 has moved through the olive ring 32 and the stops 18 come into contact with the outer surface of the pipe 30. Abutment of the stops 18 prevents the cutting edge 16 from penetrating into the outer wall of the pipe 30. It is not possible to turn the handle 26 any further and cause damage to the pipe 30. The pressure of the anvil part 6 against the inside of the pipe 30 ensures that the force of the stops 18 coming up against the pipe does not bend or deform the pipe 30.

To release the olive 32, the handle 26 is turned back in the opposite direction to retract the cutting part 8 towards the tool body 4. The split ring 32 will drop from the pipe 30 or can easily be removed without scratching. The tool 2 is then disengaged from the pipe 30 and a new olive 32 may be fitted.

The tool provides a very quick and efficient method for removing an olive from a pipe without damaging the pipe. The tool can readily be used with any diameter of pipe and olive (within the usual range of standard sizes) and does not need to be adjusted for use with different size pipes and olives. The compact arrangement of moving parts around the tool body, together^' with the movable handle, makes the tool very well adapted for use in confined spaces.

Another embodiment of the olive removal tool 2 is shown in Figure 3. This tool 2 is almost the same as in the embodiment of Figures 1 and 2, and thus will only be described in terms of its structural differences. In this embodiment, the spindle 20 is fixedly connected to the cutting part 8 by a screw 36. The screw 36 passes through a threaded bore 38 which is formed in both the cutting part 8 and the spindle 20. In order to ensure that the cutting part 8 is pulled back when the spindle 20 is retracted, the screw 26 has left hand thread while the spindle 20 has a right hand thread (or vice versa). This means that as the spindle 20 is screwed back there is a force biting against the oppositely threaded screw 36 which pulls on the cutting part 8 to help withdraw it away from the olive.

In this embodiment the distal end 24 of the spindle 20 is provided with a hexagonal external surface so as to allow connection with a spanner. Either with or without removing the tommy bar 26, a spanner may also be used to turn the spindle 20. This can be especially useful when it is desirable to apply a greater torque than is possible with the tommy bar 26, for example to split a large olive or to retract the cutter when it has become buried in an olive. This feature makes the tool 2 even more flexible and adaptable to different olive removing situations.

Operation of the tool 2 is otherwise as is described above with respect to Figure 2.

Although the preferred embodiments have been described as using a torque handle and threaded spindle to actuate incremental forward movement of the cutter, this mechanism could be replaced by a ratchet actuator instead.

Although the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various modifications may be made without departing from the scope of the invention as defined by the accompanying claims.

Claims

1. A tool for removing a compression ring from a pipe comprising means for controllably moving a cutting part in use generally radially with respect to a pipe and into engagement with a compression ring thereon, said cutting part comprising a cutter for cutting into the ring and a stop for preventing the cutter from cutting into the pipe.

2. A tool as claimed in claim 1 wherein the means is arranged in use to controllably move the cutting part linearly in a direction which is radial to the pipe and ring.

3. A tool as claimed in claim 1 or 2 wherein the linear movement is incrementally controllable.

4. A tool as claimed in claim 1 , 2 or 3 comprising means for applying a torque and means for converting the applied torque into a linear force effecting movement of the cutter.

5. A tool for removing a compression ring from a pipe comprising a cutting part, means for applying a torque, and means for converting the applied torque into controlled linear movement of the cutting part generally radially with respect to a pipe and into engagement with a compression ring thereon.

6. A tool as claimed in claim 4 or 5 wherein said means converts the applied torque into controlled linear movement of the cutting part both forwards and backwards.

7. A tool as claimed in claim 4, 5 or 6 wherein the cutting part is mounted or coupled to a threaded spindle which is rotatable in a threaded bore.

8. A tool as claimed in claim 7 wherein a torque handle is attached to the opposite end of the spindle to the cutting part to facilitate rotation thereof.

9. A tool as claimed in claim 7 or 8 wherein a portion of the spindle is shaped for connection with a spanner.

10. A tool as claimed in claim 7, 8 or" 9 wherein the cutting part is slidably mounted in a bore.

11. A tool as claimed in any of claims 7 to 10 wherein the bore(s) is/are formed in a body of the tool.

12. A tool as claimed in any preceding claim further comprising means for engaging with a pipe in use.

13. A tool as claimed in claim 12 comprising means for clamping onto a pipe in use.

14. A tool as claimed in claim 12 comprising an anvil part engageable inside a pipe in use.

15. A tool as claimed in claim 14 wherein the anvil part is arranged to contact and support the pipe wall opposite the ring section to be severed.

16. A tool as claimed in claim 14 or 15 wherein the anvil part is formed by a body of the tool.

17. A compression ring removal tool comprising an anvil part shaped for insertion into the end of a pipe, the anvil part connected to a tool body which also mounts a compression ring cutting part which is movable with respect to the anvil part, and a threaded or ratchet actuating means operable to forcibly engage the cutting part against a compression ring on a pipe end whilst engaged with the anvil part in use.

18. A tool as claimed in any of claims 5-17 wherein the cutting part comprises a cutter for cutting into the ring and a stop for preventing the cutter from cutting into the pipe.

19. A tool as claimed in any of claims 1 -4 or 18 wherein the stop comprises a blunt edge.

20. A tool as claimed in any of claims 1-4 or 18-19 wherein the stop is provided to the side of the cutter.

21. A tool as claimed in any of claims 1 -4 or 18-20 wherein the stop is provided either side of the cutter.

22. A tool as claimed in any of claims 1 -4 or 18-21 wherein the cutter and stop are integrally formed in the cutting part.

23. A tool as claimed in any of claims 1 -4 or 18-22 wherein the cutting part is dimensioned such that the width of the cutter is at least as large as the width of a standard compression ring.

24. A tool as claimed in any of claims 1 -4 or 18-23 wherein the cutter is at least 8 mm wide and preferably around 10 mm wide.

25. A tool as claimed in any of claims 1 -4 or 18-24 wherein the cutter is formed by one or more sharp edges.

26. A tool as claimed in any of claims 1-4 or 18-25 wherein the cutter comprises a single sharp edge.

27. A tool as claimed in any of claims 1 -4 or 16-26 wherein the edge is wedge- shaped.

28. A method of removing a compression ring from a pipe comprising providing a cutting part and controllably moving the cutting part generally radially with respect to a pipe having a compression ring thereon, said cutting part comprising a cutter for cutting into the ring and a stop for preventing the cutter from cutting into the pipe.

29. A method of removing a compression ring from a pipe comprising providing a tool comprising a cutting part and applying a torque to the tool, the tool comprising means for converting the applied torque into controlled linear movement of the cutting part generally radially with respect to a pipe having a compression ring thereon.

30. A method of removing a compression ring from a pipe comprising: providing a tool comprising a tool body, an anvil part connected to the tool body and a compression ring cutting part movably mounted to the tool body with respect to the anvil part; inserting the anvil part into the end of a pipe; and operating a threaded or ratchet actuating means to forcibly engage the cutting part against a compression ring on the pipe.