GB2296886A - Pipe preparing tool - Google Patents

Abstract

A pipe preparing tool comprises a frame 2 having an opening to receive a pipe. Tapered rollers 5 are mounted transversely on the frame; the first and second tapered rollers having opposed directions of taper. A cutting, scoring or penetrating means 14 is mounted on the frame and spaced apart from the first and second rollers. Clamping means apply a clamping force to the pipe such that the first and second tapered rollers engage the pipe and the cutting, scoring or penetrating means penetrates a surface layer of the pipe. When the pipe and the tool are rotated relatively to one another a helical groove is cut in at least a surface layer of the pipe.

Description

PIPE PREPARING TOOL This invention relates to pipe preparing tools, and more particularly to a novel pipe preparing tool suitable for cutting, scoring or penetrating a surface of a plastic pipe.

Plastics pipes comprising an inner core and an outer protective layer are known. The outer protective layer may, for example, provide environmental protection, or protection against mechanical damage when the pipe is, for example, laid in a trench. In joining sections of such a pipe, it has been proposed to remove the outer protective layer in the regions surrounding the pipe ends to be joined in order to permit the installation of a pipe coupler, for example an electrofusion pipe coupler.

Examples of such pipes with outer protective layers are described in PCT/FI92/00201, PCT/F193/00038, European Patent Application No. 0474583 and (P30739GB) the entire disclosures of which are incorporated herein by reference.

In practice it has proved to be extremely difficult to remove the outer protective layer cleanly from the pipe inner core without damaging the inner core.

The present invention provides a pipe preparing tool capable of cutting or scoring a helical groove in the pipe surface. In appropriate embodiments, the outer protective layer only can be penetrated, so that it can readily be peeled cleanly away from the inner core without any substantial damage to the inner core.

In one aspect the present invention provides a pipe preparing tool which comprises: a frame having an opening adapted to receive a pipe or a portion thereof; a first tapered roller means mounted transversely on the frame; a second tapered roller means mounted transversely on the frame and spaced apart from the first tapered roller means; the arrangement being such that the first and second tapered roller means have opposed directions of taper; a cutting, scoring or penetrating means mounted on the frame and spaced apart from the first and second roller means; and clamping means adapted to apply a clamping force to the pipe such that the first and second tapered roller means and the cutting, scoring or penetrating means are brought into contact with the pipe and the cutting, scoring or penetrating means penetrates a surface layer of the pipe; the arrangement being such that the pipe and the tool can be rotated relatively to one another about the axis of the pipe whereby the cutting, scoring or penetrating means produces a helical groove in at least a surface layer of the pipe.

Preferably the pipe preparing tool also comprises means for applying pressure to a surface layer of the pipe, such pressure means serving to disrupt, or partially disrupt, any adhesive bond between the outer protective layer and the inner core.

The pipe preparing tool of the invention is preferably provided with a depth control means such that the cutting, scoring or penetrating means penetrates the pipe surface layer to a predetermined depth. The depth control means can, for example, comprise one or more shoulders on the cutting, scoring or penetrating means, or rollers mounted on either side of the cutting, scoring or penetrating means.

The frame of the pipe preparing tool can, for example, comprise a generally C-shaped frame defining an opening adapted to receive the pipe or a portion thereof.

Other shapes of frame are of course possible, provided that the frame, or the components of the frame, define an opening of a width sufficient to receive the pipe or a portion thereof.

Preferably the frame is provided with a plurality of roller means, for example up to 4 rollers, at least two of which are tapered as hereinbefore described. The effect of the taper is that when the pipe preparing tool is clamped to the pipe it lies at an angle to a plane perpendicular to the axis of the pipe such that when the tool is rotated relative to the pipe the cutting, scoring or penetrating means follows a helical path around the pipe.

The cutting, scoring or penetrating means is preferably rotatable and more preferably comprises a rotatable cutting wheel having shoulders positioned on either side thereof to act as depth control means. Where the pipe is a dual layer pipe comprising an outer protective layer and an inner core, the shoulders are preferably sized and positioned so as to provide pressure means adapted to apply pressure to the outer protective layer to deform the said layer and to disrupt or partially disrupt the adhesive bond between the said layer and the inner core. The shoulders preferably also control the depth of the cutting, scoring or penetrating means such that the groove produced thereby penetrates the outer protective layer but does not extend to the inner core. Other types of cutting, scoring or penetrating means can also be used, for example, knives, blades, points and similar devices.

The cutting, scoring or penetrating means is preferably mounted on the frame such that, in operation, it occupies a position diametrically opposed to the midpoint of the chord between the first and second tapered roller means.

The clamping means is preferably arranged to apply a clamping force to the cutting, scoring or penetrating means such that the pipe is clamped between the cutting, scoring or penetrating means and the first and second roller means. Preferably the clamping means comprises a quick release screw clamp to which the cutting, scoring or penetrating means is connected.

The pipe preparing tool of the invention may, for example, be provided with adjustment means such that the width of the opening in the frame can be adjusted to accommodate different diameters of pipe. This can take the form, for example, of a sliding arm connected to the frame.

An example of a pipe preparing tool of the invention will now be described with reference to and as illustrated in the accompanying Drawings in which: Figure 1 shows a perspective view of a pipe preparing tool according to the invention; Figure 2 shows a perspective view of the pipe preparing tool of Figure 1 in position on a pipe; and Figure 3 shows a pipe prepared with a tool according to the invention and illustrates the peeling off of the outer protective layer.

Referring now to the Drawings, the pipe preparing tool illustrated generally at 1 comprises a frame 2, of generally C-shaped construction, defining an opening 3 within which the pipe 4 can be received as shown in Figure 2. The frame is provided with four transversely mounted, spaced apart, rollers 5, 6, 7 and 8 situated on a first projecting arm 9. Outer rollers 5 and 8 are tapered and have opposite hands. The rear section 10 of the frame 2 has a channel 11 within which a sliding arm 12 is located. The arm projects from the rear of the frame and carries at its remote end 13 a transversely mounted rotatable cutting wheel. The cutting wheel 14 has a blade 15 and shoulders 16 arranged on each side of the blade.

Both the cutting wheel 14 and the rollers 5, 6, 7 and 8 are freely rotatable.

The sliding arm 12 is connected to a screw threaded rod 17 which passes through a threaded bush 18 mounted at the end of a second projecting arm 19 of the frame 2.

The rod 17 is provided with a turning handle 20.

In operation, the tool 1 is placed around the pipe 4 and the handle 20 rotated in order to screw the rod 17 into the bush 18 whereby the sliding arm 12 is urged in the direction of the first arm 9 and the rollers 5, 6, 7 and 8. Ultimately the pipe is clamped between the rollers mounted on the arm 9 and the cutting wheel 14 mounted on the sliding arm 12. As the threaded rod 17 is screwed further into the bush 18 pressure is applied to the cutting wheel 14 so that the blade 15 penetrates the outer layer of the pipe 4 until the shoulders 16 come into contact with the outer layer and limit further penetration. The pressure of the shoulders 16 is sufficient to cause local distortion of the surface which can break or weaken the adhesion between the outer protective layer and the inner core in the areas adjacent to the groove produced by the blade 15.

Because the rollers 5 and 8 have tapers of opposite hand, the tool 1 lies at an angle to the plane perpendicular to the axis of the pipe 4. Rotation of the tool relative to the pipe therefore causes the cutting wheel 14 to describe a helical path around the pipe 4 thereby producing a helical groove 21 in the outer surface of the pipe.

As can be seen from Figure 3, the helical groove 21 and the bond disruption produced by the shoulders 16 facilitates removal of the outer surface protective layer of the pipe as a thin helical strip 22 which can be peeled from the pipe to expose a fresh surface layer which can be used, for example, for electrofusion welding. This peeling can be carried out when the groove is first cut, or alternatively the protective layer can be left in place until immediately before the fusion step is carried out.

If desired, the cutting wheel and/or shoulders may be exchanged to accommodate pipes having different surface layer thicknesses.

Whilst the invention has been described with references to a tool for cutting a groove in an outer protective layer of a pipe, it will be apparent that the tool could also be used to cut a helical groove throughout the entire thickness of the pipe to produce a helical plastics strip, should such be desired.

The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps or any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims (16)

1. A pipe preparing tool which comprises: a frame having an opening adapted to receive a pipe or a portion thereof; a first tapered roller means mounted transversely on the frame; a second tapered roller means mounted transversely on the frame and spaced apart from the first tapered roller means; the arrangement being such that the first and second tapered roller means have opposed directions of taper; a cutting, scoring or penetrating means mounted on the frame and spaced apart from the first and second roller means; and clamping means adapted to apply a clamping force to the pipe such that the first and second tapered roller means and the cutting, scoring or penetrating means are brought into contact with the pipe and the cutting, scoring or penetrating means penetrates a surface layer of the pipe; the arrangement being such that the pipe and the tool can be rotated relatively to one another about the axis of the pipe whereby the cutting, scoring or penetrating means produces a helical groove in at least a surface layer of the pipe.

2. A tool according to Claim 1, which comprises means for applying pressure to a surface layer of the pipe, such pressure means serving to disrupt, or partially disrupt, an adhesive bond between the surface layer and the inner core of the pipe.

3. A tool according to Claim 1 or 2, which is provided with a depth control means such that the cutting, scoring or penetrating means penetrates the pipe surface layer to a predetermined depth.

4. A scoring tool according to any of the preceding claims, which is provided with depth control means and/or pressure means which comprise one or more shoulders on the cutting, scoring or penetrating means.

5. A tool according to any of the preceding claims, which is provided with a generally C-shaped frame defining an opening adapted to receive a pipe or a portion thereof.

6. A tool according to any of the preceding Claims, in which the cutting, scoring or penetrating means comprises a rotatable cutting wheel.

7. A tool according to any of the preceding Claims, in which the cutting, scoring or penetrating means is mounted on the frame such that, in operation, it occupies a position diametrically opposed to the mid-point of the chord between the first and second tapered roller means.

8. A tool according to any of the preceding Claims, in which the clamping means is arranged to apply a clamping force to the cutting, scoring or penetrating means such that, in operation, the pipe is clamped between the cutting means and the first and second roller means.

9. A tool according to Claim 8, in which the clamping means comprises a quick release screw clamp to which the cutting, scoring or penetrating means is connected.

10. A tool according to any of the preceding Claims, which is provided with adjustment means such that the width of the opening in the frame can be adjusted to accommodate different diameters of pipe.

11. A tool according to Claim 10, in which the adjustment means comprises a sliding arm connected to the frame.

12. A tool according to any of the preceding Claims, substantially as hereinbefore described with reference to and as illustrated in the accompanying Drawings.

13. A method for producing a groove in the surface of a pipe comprising an inner core and an outer protective layer in which there is used a pipe preparing tool according to any of Claims 1 to 12.

14. A method according to Claim 13, in which the outer protective layer is peeled away from the inner core as a helical strip.

15. A method according to Claim 13 or 14 substantially as hereinbefore described.

16. A pipe preparing tool adapted to cut a helical groove of predetermined depth in a plastics pipe.