WO1999038634A1

WO1999038634A1 - Pipe preparing tool

Info

Publication number: WO1999038634A1
Application number: PCT/GB1999/000102
Authority: WO
Inventors: Steven Robert Wood
Original assignee: Uponor Innovation Ab
Priority date: 1998-01-28
Filing date: 1999-01-27
Publication date: 1999-08-05
Also published as: GB0018458D0; AU2173199A; GB9801844D0; GB2348845A; GB2333732A

Abstract

A pipe preparing tool which comprises: a frame of generally C-shaped construction having an arcuate portion adapted, in use, to be in intimate contact with the outer surface of the pipe; and a cutter assembly mounted on the frame and comprising a cutting, scoring or penetrating means, the cutting, scoring or penetrating means being disposed on the said arcuate portion of the frame.

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 plastic pipe.

Composite 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 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, such as, for example, an electrofusion pipe coupler. Examples of such pipes with outer protective layers are described in WO-A-9300212 , WO-A-9215818 , European Patent Application No 0474583 and in O-A- 9622485 the entire disclosures of which are incorporated herein by reference for all purposes.

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 when using conventional tools. In GB1487033 there is described a tube cutting and chamfering tool comprising an adjustable C- shaped frame, a pair of spaced cutting wheels arranged in a common plane, supporting rollers for the tube, and a chamfering cutter adjustably located between the two cutting wheels. This tool is quite complex in design and is not readily adapted to remove the outer protective layer of a composite pipe.

GB1458366 describes a tool for cutting a cable sheath which comprises a loop-like frame, including at least two hingedly connected parts, means for releasably holding the frame parts in closed loop form, a handle connected to the frame, and a cutter assembly mounted for adjustment both inwardly and outwardly of the loop and angularly about the axis of its inward and outward movement. The cable sheath is supported by rollers mounted on the frame and, in some embodiments, also on the cutter assembly. This tool is complex in both design and operation .

In GB2296886 there is described and claimed 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.

This tool works well in practice, and can be used to strip off the outer layer of a composite pipe, but again some further simplification of the design would be desirable. In particular, it would be desirable to provide a cheaper tool and one wherein the number of moving parts, such as rollers, can be reduced.

The present invention provides a pipe preparing tool of relatively simple construction capable of cutting or scoring, preferably a helical groove in, a pipe. 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 a first aspect, the present invention provides a pipe preparing tool which comprises:

a frame of generally C-shaped construction having an arcuate portion adapted, in use, to be in intimate contact with the outer surface of the pipe; and

a cutter assembly mounted on the frame and comprising a cutting, scoring or penetrating means, the cutting, scoring or penetrating means being disposed on the said arcuate portion of the frame, and

depth control means such that the cutting, scoring or penetrating means penetrates the pipe surface layer to a predetermined depth, for example, to the depth of the outer layer of a composite pipe.

The depth control means can, for example, comprise a screw threaded member mounted on a hollow screw threaded boss member on the frame, the screw threaded member being rotatable to control the depth of cut .

The pipe preparing tool preferably comprises a generally C-shaped frame defining an opening adapted to receive the pipe or a portion thereof. The frame is adapted to slide onto the pipe such that an arcuate portion, and preferably the whole of the inner surface of the frame is in relatively close conformity with the outer surface of the pipe, whilst allowing for some ovality of the pipe circumference in practice. In this specification, this is termed "intimate contact". Preferably, the C-shaped frame forms a snap fit with the pipe. A preferred embodiment for use with oval tools is arranged to clamp the pipe in a multi-point, preferably three point, manner as illustrated in figure 5 at A, B and C. The clamping points are arranged to be at angular displacements of between 120 and 30 degrees. Preferably, an embodiment is arranged such that two of the clamping points are disposed either side of a point on the frame inner surface which is diametrically opposite the cutting assembly. In a preferred embodiment, these two points are each angularly disposed 30 degrees from the point which is diametrically opposite the cutting assembly.

Whilst it may be possible for the generally C-shaped frame to be resiliently deformable, in order to accommodate different sizes of pipe, it is preferable for the frame to be relatively rigid. Although this may limit the use of the tool effectively to one diameter of pipe, the construction of the tool is such that it is a relatively simple matter to provide tools with different sized frames in order to accommodate different diameter pipes. It may indeed be possible to exchange the cutter assembly between different frames in order to reduce costs .

The cutting, scoring or penetrating means is preferably rotatable about an axis normal to the surface of the pipe. The cutting, scoring or penetrating means can, for example, comprise a knife blade, which can be mounted in a suitable holder which is part of a cutter assembly. In a preferred embodiment according to the invention the blade holder and blade are axially rotatable through at least 10 degrees to facilitate a helical cutting action, preferably at least 90 degrees, for example, 360 degrees. In preferred embodiments, the depth of cut can be adjusted, for example, using a handle, knob or thumb screw on the cutter assembly. Any suitable cutting, scoring, or penetrating means can be used in the pipe preparing tool according to the invention, for example, a tool bit comprising a fixed blade with a straight bottom, a tool bit comprising a fixed blade with a vee-shaped bottom, or a tool bit having a knife edge and a lifting action. Other types of cutting, scoring or penetrating means can also be used, for example, cutting wheels, points and similar devices.

The cutting, scoring or penetrating means is preferably mounted on the frame such that, in operation, it occupies a position substantially at the mid-point of an arcuate portion of the frame which is adapted, in use, in accordance with the invention, to be in intimate contact with the surface of the pipe. Where the entire inner surface of the C-shaped frame is in intimate contact with the pipe, the cutting, scoring, or penetrating means is preferably mounted at a point from 5 cms to 30 cms from an end of the frame. Preferably, the position of the cutting, scoring, or penetrating means with respect to the end of the frame varies according to the diameter of the frame.

Embodiments of a pipe preparing tool of the invention will now be described, by way of example only, with reference to the accompanying Drawings in which: Figure 1 shows a sectional side elevation view of a first pipe preparing tool according to the invention;

Figures 2 (a) to 2 (d) show sectional side elevational views of the cutter assemblies of two further pipe preparing tools in different rotational positions, and Figure 2 (e) shows the tools in plan view;

Figure 3 shows a perspective view of a fourth pipe preparing tool according to the invention;

Figure 4 shows a pipe prepared with a tool according to the invention and illustrates the peeling off of the outer protective layer; and

Figure 5 shows an embodiment of a pipe preparing tool which utilises a multi-point clamping action.

Referring now to Figure 1, the pipe preparing tool illustrated generally at 1 comprises a frame 2, of generally C-shaped construction, defining an opening 3 within which a pipe (not shown) can be received.

The inner arcuate surface 4 of the frame 2 is arranged to follow the contours of the outer surface of the pipe, but at least the section designated by the broken line 5 of the inner surface of the frame is, in use, in intimate contact with the pipe surface.

The cutter assembly 6 is mounted in a hole 7 in the frame 2. The cutter assembly 6 comprises an upstanding hollow boss member 8 which has a foot 9 which is rigidly held within the hole 7 in the frame, a blade holder 10, which is rotatably disposed within a hollow shaft 11 in the boss member 8, and a threaded cap member 12 having a lever handle 13.

The cap member 12 has an internally threaded section 14 which engages with a complimentary threaded section 15 on the outer cylindrical surface on the boss member 8. Turning the cap member 12 by means of the handle 13 alters the angular orientation of the blade holder 10 about its axis 16. Height adjustment for the blade holder is provided by the nut 17 which is disposed on the threaded outer surface 18 of the blade holder 10. This has the effect of raising and lowering the blade holder with respect to the boss member 8 and the cap member 12. A cutter blade 19 is rigidly held at the lower extremity 20 of the blade holder 10. It will be appreciated that the blade and blade holder have been shown in an exaggerated extended position for the sake of clarity, and that in practice the blade 19 would be retracted closer to the arcuate surface 5 of the frame 2. In use, a pipe is placed within the opening 3 and the tool 1 is slid along the pipe to the position at which a cut in the outer surface is required. The depth of cut and orientation of the blade 19 are then adjusted by means of the nut 17 and the handle 13 respectively, and the entire tool 1 is then rotated about the pipe. The orientation of the blade 19 will determine whether a straight cut or a spiral cut is obtained. After the cutting operation is completed, the tool is removed and the outer surface of the composite can be peeled off as required.

Referring now to Figures 2 (a) and (b) , there is shown a second embodiment of a cutter assembly 30 according to the invention, mounted on an end section 31 of a C-shaped frame. In Figure 2(a) the cutter assembly 30 is mounted upon a hollow boss member 32 which is integral with the frame 31. A slot 33 in the boss member 32 extends radially around a quarter of its circumference and within the boss member is located a cylindrical blade holder 34 having a radially extending lever handle 35 which protrudes through the slot 33. The cutter assembly is surmounted by a threaded cap member 36 which is connected to the blade holder 34 and is rotatably mounted upon the boss member 32, engaging with an external thread 37 on the outer surface thereof. The blade 38 protrudes through a hole 39 in the frame 31 and can be moved in an axial direction by rotating the cap member 36. The blade member 38 can also be rotated about its axis, to a maximum extent of 90°, by rotation of the handle 35 as shown in Figure 2 (b) .

Figures 2 (c) and (d) show a very similar design to that of Figures 2(a) and 2(b) except that in this case the blade holder 41 extends only part way along the boss member 42 and is surmounted by a spring washer 43. A tubular projection 44 extends downwardly from the cap member 36 and is connected to the blade 45. As before, the depth and orientation of the blade 45 can be adjusted by turning respectively the cap member 36 and the handle 35. The extreme positions of the handle 35 are shown in Figure 2 (e) , which is a plan view of the cutter assembly as applied to any of the embodiments of Figures 2 (a) to (d) .

A further embodiment of a pipe preparing tool according to the invention is shown in Figure 3. This tool, illustrated generally at 50, comprises a C-shaped frame 51 and a cutter assembly 52. The cutter assembly comprises a blade holder 53 having a blade 54 mounted to an end face thereof. The blade holder is rotatable between end stops 55 and 56 and can be rotated by means of a knob 57. In use, the tool 50 is positioned around the pipe as before, the orientation of the blade 54 selected manually, by rotating the knob 57, and the tool is then rotated around the pipe using the knob 57 to apply the appropriate pressure and direction. The position of the stops 55 and 56 is such that the blade has approximately 10° of rotation between them to provide either for a ring cut or a spiral cut .

An example of a composite pipe prepared in accordance with the invention is shown in Figure 4. The composite pipe 60 has an outer layer 61 in which a spiral groove 62 has been cut using a tool in accordance with the invention. A portion of the outer layer 61 has been peeled back as shown at 63.

The invention provides a simple and economical tool for making spiral and ring cuts in the outer surface of a pipe, and which is particularly suitable for assisting in the peeling back and removal of the outer layer of a composite pipe, for example, when the pipe is to be joined using an electrofusion coupler. Removal of the outer surface layer can be achieved to expose a clean pipe surface for electrofusion without damaging the underlying body of the pipe. 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 groove throughout the entire thickness of the pipe to cut the pipe to length or 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

1. A pipe preparing tool which comprises :

a cutter assembly mounted on the frame and comprising a cutting, scoring or penetrating means, the cutting, scoring or penetrating means being disposed on the said arcuate portion of the frame, and depth control means such that the cutting, scoring or penetrating means penetrates the pipe surface layer to a pre-determined depth.

2. A tool according to Claim 1, wherein the depth control means comprises a screw threaded member mounted on a hollow screw threaded boss member on the frame, the screw threaded member being rotatable to control the depth of cut.

3. A tool according to Claim 1 or 2 , wherein the frame is adapted to slide onto the pipe in such a manner that the whole of the inner surface of the frame is in conformity with the outer surface of the pipe.

4. A tool according to any one of the preceding claims, wherein the minimum length of the arcuate section of the frame adapted to be in intimate contact with the pipe spans a predeterminable range.

5. A tool according to any one of the preceding claims, in which the cutting, scoring or penetrating means is rotatable about an axis normal to the surface of the pipe.

6. A tool according to Claim 5, wherein the cutting, scoring or penetrating means is axially rotatable through at least 10┬░ .

7. A tool according to any one of the preceding claims, wherein the cutting, scoring or penetrating means comprises a tool bit comprising a fixed blade with a straight bottom, a tool bit comprising a fixed blade with a vee-shaped bottom, or a tool bit having a knife edge and a lifting action.

8. A tool according to any one of the preceding claims, wherein the cutting, scoring or penetrating means is mounted on the frame such that, in use, it occupies a position substantially at the mid point of an arcuate portion of the frame in intimate contact with the surface of the pipe.

9. A tool according to any one of Claims 1 to 7, wherein the entire inner surface of the C-shaped frame is adapted to be in intimate contact with the pipe, in use, and the cutting, scoring or penetrating means is mounted at a point a predeterminable distance from an end of the frame .

10. A pipe preparing tool substantially as hereinbefore described with reference to and as illustrated in the accompanying Drawings.

11. A pipe preparing tool according to any one of the preceding claims substantially as hereinbefore described.

12. A composite pipe having a grooved outer surface prepared using a pipe preparing tool according to any of the preceding claims .