GB2580585A

GB2580585A - Tool for chamfering pipes

Info

Publication number: GB2580585A
Application number: GB1819816.8A
Authority: GB
Inventors: Caspar Bamford Daniel
Original assignee: Metex Online Ltd
Current assignee: Metex Online Ltd
Priority date: 2018-12-05
Filing date: 2018-12-05
Publication date: 2020-07-29
Also published as: GB201819816D0

Abstract

The tool for chamfering pipes (14, Figure 1) includes a cutting body 10 that is rotationally symmetrical about a rotation axis (A, Figure 2). The cutting body has a cylindrical portion 12, open at a first end and closed by an end wall 20. At a second end, a shoulder 22 is formed where the end wall meets the cylindrical portion. There is at least one cutting region. The or each cutting region includes an aperture 26 formed through the body in the region of the shoulder. A cutting blade 40 extends through the aperture. The blade has a chamfer cutting surface (46, Figure 9), at least part of which is radially inward of the aperture and that is inclined at a chamfer angle with respect to the rotation axis. The blade is a discrete component connected to the cutting body. The blade may include a second cutting surface 48 that extends radially inwardly from the chamfer cutting surface. The blade may be removably secured by inter-engagement of cooperating features, threaded fasteners, rivets, welding, or adhesive bonding. The tool may have two, three or four cutting regions, symmetrically disposed about the axis with identical blades.

Description

Tool for chamfering pipes This invention relates to a tool for chamfering pipes.

The assembly of push-fit joints between lengths of plastic pipe, such as drainage pipes, can be facilitated if a free end portion of a length of pipe is chamfered before it is pushed into a joint collar. Manual assembly of plastic underground drainage pipes in particular is virtually impossible without the free end being chamfered. The chamfer has several beneficial effects: it helps to centralise the pipe within the joint collar and it reduces the risk that the end of the pipe will damage flexible seals within the joint collar.

In GB-A-2 527 198 there is disclosed a tool for forming a chamfer at an end portion of a pipe that comprises a frusto-conical region within which there is a plurality of cutting formations. While such a tool can perform satisfactorily, it has some disadvantages. The angle of the chamfer is fixed by the cone angle of the frusto-conical region. It is also difficult to restore the performance of the tool once the cutting formations have been blunted through use.

It is an aim of this invention to provide a tool for chamfering pipes that overcomes, or at least ameliorates, these disadvantages.

To this end, from a first aspect, the present invention provides a tool for chamfering pipes comprising a cutting body that is rotationally symmetrical about a rotation axis; the cutting body has a cylindrical portion, open at a first end and at least partly closed by an end wall, at a second end, a shoulder being formed where the end wall meets the cylindrical portion, there being at least one cutting region, which cutting region includes an aperture formed through the body in the region of the shoulder and a cutting blade that extends through the aperture, which blade has a chamfer cutting surface at least part of which is radially inward of the aperture and that is inclined at a chamfer angle with respect to the rotation axis and which blade is a discrete component connected to the cutting body.

Thus, the angle of the chamfer that the tool forms on a pipe is determined by the blade or blades and is not fixed by the body, so allowing a range of tools to be manufactured conveniently.

In addition, the blade may include a second cutting surface that extends radially inwardly from the chamfer cutting surface, typically in a direction that is approximately perpendicular to the rotation axis. In use, the second cutting surface operates to trim and deburr the end of a length of pipe.

The blade may be secured by one or more of: interengagement of cooperating features of the blade and the body, threaded fasteners, rivets, welding, adhesive bonding or similar.

The blade may be secured to the body in such a manner that it can be removed and replaced after manufacture. This enables a user to replace a blade that has become worn or to install a blade that is particularly suited to a specific task.

Typical embodiments include a plurality of cutting regions, most typically two, three or four in number. The cutting regions are preferably disposed symmetrically about the rotation axis. The blades of the cutting regions may be substantially identical, or they may vary in accordance with the last three preceding paragraphs or otherwise.

The end wall may be shaped as a disc that substantially closes the end of the body. Alternatively, it may include openings or have a minimal structure, for example, comprising a plurality of radially-extending spokes.

The body may be formed of metal or of plastic material.

Embodiments of the invention preferably further include a spigot that projects centrally from the end wall, away from the first end, and coaxial with the rotation axis.

From a second aspect, this invention provides a method of chamfering a pipe comprising the steps of applying a tool according to any preceding claim to an end portion of a pipe and causing the tool to rotate about its rotation axis with the or each cutting blade in contact with the pipe.

In such a method, the tool may be rotated manually or, more commonly the tool may be rotated mechanically using powered apparatus such as a drill.

An embodiment of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings, in which: Figures 1 and 2 show an embodiment of the invention in use on a length of pipe; Figures 3 to 6 are additional views of the embodiment of Figures 1 and 2; Figure 7 shows the embodiment of Figures 1 to 6 with a body part rendered transparently; Figure 8 shows a body being a part of the embodiment of Figures 1 to 7; and Figure 9 shows a blade being a part of the embodiment of Figures 1 to 7.

With reference to the drawings, a tool embodying the invention includes a one-piece body 10 formed from suitable metal or plastic material. The body is centred upon and is rotationally symmetrical about a rotational axis A. The body 10 has a guide region 12 that is shaped as a hollow cylinder centred upon the rotational axis. The inner diameter of the guide region 12 is marginally greater than the outer diameter of a pipe 14 with which the tool is intended for use. Specifically, the diameter is such that the guide region 12 can rotate freely on the pipe 14 with minimal radial movement.

The body 10 has an open end that extends about the rotational axis A. A rounded lip 16 projects from the body to surround the open end. The body 10 also has a closed end, opposite the open end, that is closed by an end wall 20 that is shaped substantially as a disc.

The end wall 20 is formed contiguously with the guide region 12, with which it is interconnected at a shoulder 22.

Three cutting regions are formed in the body spaced symmetrically about the axis A. Each cutting region includes a hole 26 that passes through the material of the body 10. The hole 26 is formed to extend into the guide region 12 and the end wall 20, passing through the shoulder 22. The portion of the hole 26 that extends into the end wall is bounded by at least one edge, referred to as the trailing edge, shown at 30, that extends along a radius of the end wall 20. The trailing edge extends into the guide region 12 in a direction parallel to the rotational axis A. A first notch 32 extends from the trailing edge into the end wall 20 and a second notch 34 extends from the trailing edge into the guide region 12.

Each cutting region further includes a planar blade 40 formed from a flat piece of hard metal and shaped as shown in Figure 9. The blade 40 has a thickness that makes it a close fit within the notches 32, 34 of the holes 26 and is shaped and dimensioned to have engagement surfaces 42, 44 and adjacent faces that can engage with the material of the body 10 adjacent to the notches 32, 34. This ensures that each blade 40 can be accurately and securely located on the body 10 next to the trailing edge of a respective one of the holes 26.

Each blade has two cutting edges: a chamfering edge 46 and a trimming edge 48 that meet one another with an angle of greater than 90°. When the blade 40 is located on the body 10, its plane extends parallel to the rotational axis A. The trimming edge 48 extends radially from a radius less than the inner radius of a pipe 14 with which the tool is intended to be used to a radius less than the outer radius of a pipe 14 with which the tool is intended to be used. The chamfering edge 46 extends at an acute angle with the rotational axis A, increasing in radius in a direction away from the trimming edge 48 to a radial position greater than the outer radius of a pipe 14 with which the tool is intended to be used.

The body is carried on a spigot 50. The spigot has a cylindrical shank 52, a boss 54 of larger diameter. An externally-threaded stub 56 extends from the boss 54. A central hole 60 is formed through the end wall 20. In the assembled tool, the threaded stub 56 passes through the hole such that the boss 54 is in contact with the end wall 20 and the shank 52 projects coaxially with the rotational axis A away from the guide region 12. A nut 60 and washer 62 are applied to the stub 56 to secure the spigot 50 in place on the end wall 20 such that the spigot 50 is fast with the body so that rotation of the spigot will cause the body to rotate about its rotation axis.

For use, the shank 52 of the spigot is clamped in the chuck of an electric drill (not shown). A pipe 14 to be chamfered is inserted into the guide region until it is close to the blades 40. The drill is then activated to cause the tool to rotate about rotation axis A. The pipe is then pushed further into the guide region 12 until it makes contact with the blades 40. The chamfering edge 46 forms a tapering chamfer at an end portion of the pipe and the trimming edge 48 simultaneously removes irregularities from the end surface of the pipe 14. Material trimmed from the pipe can escape from the tool through the holes 26.

It should be noted that the direction of rotation is such that the trailing edge 30 of each hole 26 makes contact with the blade 40 to apply a driving force to it and to maintain the blade 40 in a plane that is normal to the direction of rotation.

Claims

Claims 1. A tool for chamfering pipes comprising a cutting body that is rotationally symmetrical about a rotation axis; the cutting body has a cylindrical portion, open at a first end and closed by an end wall, at a second end, a shoulder being formed where the end wall meets the cylindrical portion, there being at least one cutting region, which cutting region includes an aperture formed through the body in the region of the shoulder and a cutting blade that extends through the aperture, which blade has a chamfer cutting surface at least part of which is radially inward of the aperture and that is inclined at a chamfer angle with respect to the rotation axis and which blade is a discrete component connected to the cutting body.
2. A tool according to claim 1 in which the blade includes a second cutting surface that extends radially inwardly from the chamfer cutting surface.
3. A tool according to claim 2 in which the second cutting surface extends in a direction that is approximately perpendicular to the rotation axis.
4. A tool according to any preceding claim in which the blade is secured by one or more of: interengagement of cooperating features of the blade and the body, threaded fasteners, rivets, welding and adhesive bonding.
5. A tool according to any preceding claim in which the blade is secured to the body in such a manner that it can be removed and replaced after manufacture.
6. A tool according to any preceding claim that includes a plurality of cutting regions.
7. A tool according to claim 6 that includes one, two, three or four cutting regions.
8. A tool according to claim 6 or claim 7 in which the cutting regions are disposed symmetrically about the rotation axis.
9. A tool according to any one of claims 6 to 8 in which the blades of the cutting regions are substantially identical.
10. A tool according to any preceding claim in which the end is shaped as a disc that substantially closes the end of the body.
11. A tool according to any one of claims 1 to 9 in which the end wall includes a plurality of radially-extending spokes.
12. A tool according to any preceding claim in which the body is metal.
13. A tool according to any one of claims 1 to 11 in which the body is formed from plastic material.
14. A tool according to any preceding claim further including a spigot that projects centrally from the end wall, away from the first end, and coaxial with the rotation axis
15. A method of chamfering a pipe comprising the steps of applying a tool according to any preceding claim to an end portion of a pipe and causing the tool to rotate about its rotation axis with the or each cutting blade in contact with the pipe.
16. A method according to claim 15 in which the tool is rotated manually.
17. A method according to claim 15 in which the tool is rotated mechanically.