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Patent Searching and Data


Title:
PIPE CUTTING MACHINE AND CIRCULAR SAW BLADE WITH CHAMFERING TEETH
Document Type and Number:
WIPO Patent Application WO/1998/016342
Kind Code:
A1
Abstract:
A length of pipe to be cut is laid on rollers (7) and a motor (1) is operated to rotate a disk (9). The motor (1) is then tilted about a hinge (13) so that teeth on the outer edge of the disk (9) cut into the pipe (8). The pipe (8) is then rotated manually, in the opposite direction to the rotational direction of the disk (9), until it has been cut through fully.

Inventors:
CHINN NORMAN JOHN LEVI (GB)
LE GALLAIS LIONEL (GB)
Application Number:
PCT/GB1997/002699
Publication Date:
April 23, 1998
Filing Date:
October 13, 1997
Export Citation:
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Assignee:
CHINN NORMAN JOHN LEVI (GB)
LE GALLAIS LIONEL (GB)
International Classes:
B23D45/12; B23D61/04; B27B33/20; (IPC1-7): B23D45/12; B23D61/04; B27B33/20
Foreign References:
DE2709024A11978-09-07
DE4013470A11991-10-31
EP0259847A11988-03-16
DE3301919A11984-07-26
US2327863A1943-08-24
US5497816A1996-03-12
US4777723A1988-10-18
Other References:
PATENT ABSTRACTS OF JAPAN vol. 13, no. 560 (M - 906) 13 December 1989 (1989-12-13)
PATENT ABSTRACTS OF JAPAN vol. 9, no. 121 (M - 382) 25 May 1985 (1985-05-25)
Attorney, Agent or Firm:
James, Michael John Gwynne (Laine & James 22 Rodney Roa, Cheltenham Gloucestershire GL50 1JJ, GB)
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Claims:
CLAIMS
1. A pipe cutting assembly comprising a framework having aligned pairs of rollers for receiving a pipe so that it can be rotated on the rollers, and a stand carrying a motorised cutting disk such that the disk can be lowered onto the pipe to cut vertically in a plane across the pipe axis.
2. A pipe cutting assembly according to Claim 1, wherein the motor for the cutting disk is mounted to the stand by a pivot which allows the cutting disk to be lowered into contact with the pipe and to cut it through.
3. A pipe cutting assembly according to Claim 1 or Claim 2, wherein the cutting disk is shrouded by a guard projecting from the motor.
4. A pipe cutting assembly according to any one of Claims 1 to 3, wherein the stand incorporates a height adjustment mechanism to allow for pipes of differing diameter to be cut.
5. A pipe cutting assembly according to any one of Claims 1 to 4, wherein the framework carrying the rollers is extendable to allow for supporting pipes of differing lengths.
6. A pipe cutting disk having cutting teeth on the circumferential edge of the disk and blades on the side faces of the disk, the blades being set on the same radius from the disk axis and having angled cutting faces directed away from the disk axis for creation of chamfered edges to the cut ends of the pipe.
7. A pipe cutting disk according to Claim 6, together with a sleeve which will receive a pipe and has a cutting slot through which the cutting disk can attack the pipe and which will incorporate fixing means enabling one or other of the cut sections of the pipe to be held against rotation whilst the other one is rotated to achieve a clean chamfer against the blades on the cutting disk.
8. A pipe cutting disk according to Claim 7, wherein the blades are formed as outward extensions of the roots of the cutting teeth.
9. A pipe cutting disk according to Claim 7, or Claim 8 wherein the sleeve is part of a relatively simple cutting assembly in which a motor and cutting disk are pivotally mounted on the sleeve itself.
10. A pipe cutting disk according to and one of Claims 6 to 9 in combination with the pipe cutting assembly according to any one of Claims 1 to 5.
11. A pipe cutting assembly or a pipe cutting disk substantially as herein described with reference to the accompanying drawings.
Description:
PIPE CUTTING MACHINE AND CIRCULAR SAW BLADE WITH CHAMFERING TEETH The cutting of large diameter pipes (for example for drainage purposes) presents a problem since the pipes are large and heavy to handle and, for many purposes, the pipe needs to have a clean and accurate cut end face, ideally with a chamfer. This is a particular problem with clay pipes which can easily fracture if not cut correctly. The production of a clean-cut chamfer on large and small pipes of a variety of materials also presents a problem.

From one aspect of the invention there is provided a pipe cutting assembly comprising a framework having aligned pairs of rollers for receiving a pipe so that it can be rotated on the rollers, and a stand carrying a motorised cutting disk such that the disk can be lowered onto the pipe to cut vertically in a plane across the pipe axis.

This assembly provides a mounting for large and heavy pipes in such a manner that the pipe can easily be rotated during the cutting procedure and a clean vertical cut is assured.

The assembly will advantageously have the motor for the cutting disk mounted to the stand by a pivot which allows the cutting disk to be lowered into contact with the pipe and to cut it through. For safety the cutting disk will ideally be shrouded by a guard projecting from the motor.

The stand can incorporate a height adjustment mechanism to allow for pipes of differing diameter to be cut.

The framework carrying the rollers ideally will be

extendable to allow for supporting pipes of differing lengths.

According to a further aspect of the invention there is provided a pipe cutting disk having cutting teeth on the circumferential edge of the disk and blades on the side faces of the disk, the blades being set on the same radius from the disk axis and having angled cutting faces directed away from the disk axis for creation of chamfered edges to the cut ends of the pipe.

Use of such a disk enables a pipe to be cut into two parts by the cutting teeth and as the disk is lowered further the blades then create a chamfer on the cut ends of the pipe. The blades can be formed as outward extensions of the roots of the cutting teeth. Such a cutting disk is ideally used in combination with the pipe cutting assembly of the invention as hereinbefore defined.

A sleeve can be provided which will receive a pipe and has a cutting slot through which a cutting disk can attack the pipe and which will incorporate fixing means enabling one or other of the cut sections of the pipe to be held against rotation whilst the other one is rotated to achieve a clean chamfer against the blades on the cutting disk.

This sleeve could be part of a relatively simple cutting assembly in which a motor and cutting disk are pivotally mounted on the sleeve itself.

The invention may be performed in various ways and a preferred embodiment will now be described, by way of example, with reference to the accompanying drawings, in

which:- Figures 1 and 2 are front and plan views respectively of a pipe cutting assembly of the invention; Figures 3 and 4 are views of the assembly of Figure 1 from one end and the other end respectively, in an operating condition; Figures 5 and 6 are respective views of a face and the edge of a cutting disk shown in Figures 3 and 4; Figures 7 and 8 illustrate modified forms of cutting disk to that shown in Figure 5; and Figure 9 shows a part of a mounting arrangement for a pipe being cut.

The equipment shown in Figures 1 to 4 of the drawings comprise a motor 1 mounted on to a stand 2 to one side of a support framework 3. The framework 3 carries a number of pairs of rollers 4, 5, 6 and 7 (rollers 5 and 6 have been omitted from Figure 1 for clarity) . These rollers will provide support for a length of pipe 8 (see Figures 3 and 4) which is to be cut by a rotating cutting disk 9 driven by the motor 1 and housed within a fixed upper guard 10 and a pivoted lower guard 11. The height of the disk 9 can be adjusted by operating a scissor jack 12, to suit the diameter of the pipe to be cut (two different sizes 8A and 8B, are shown in Figure 4).

In use the length of pipe to be cut is laid on the rollers 4, 5, 6 and 7 and the motor 1 is operated to rotate the disk 9. The motor 1 is then tilted about a hinge 13 so that teeth on the outer edge of the disk 9 cut into the pipe

8. The pipe 8 is then rotated, manually, in the opposite direction to the rotational direction of the disk 9, until it has been cut through fully. A preferred design of disk is illustrated in Figures 5 and 6. This carries a series of outer teeth 14 which cut through the pipe 8 to separate it into two parts. The two face surfaces 15 of the disk 9 also carry a pair of blades 16. As can be seen from Figure 6 these blades 16 are angled so that, as they act against the already cut end of the pipe 8, they will form a chamfered surface 17 (such as that shown in Figure 8). The design of the disk could be modified, as shown in Figure 7. Here the edge of the disk is formed into a number of segments 18 each of which carries some of the cutting teeth 14. This gives the disk greater resilience during the cutting process.

This disk also carries a ring of blades 19 which cut the chamfer, rather than just 2 on each side. Another possibil- ity, as shown in Figure 8, is to form the blades 20 as sideways extensions from the root portions of the cutting teeth 14.

As shown in Figure 9 a sleeve 21 can be provided through which a pipe 8 of a particular diameter can be located. During the main cutting process the sleeve 21 could be mounted on the rollers 5 and 6. It is envisaged however that the sleeve 21 will have a lightweight motor assembly and cutting disk 9 pivotally carried thereon, as a self contained unit. The pipe can be rotated in the sleeve during cutting through of the pipe. This would be particu- larly suited to lightweight pipes formed from plastics

material. For the final stage of creating the chamfer 17 each cut portion of the pipe 8 can be fixed to a respective half portion of the sleeve 21 in turn by means of screws 22 so that the other cut portion can be offered up to the blades 16 on one side of the cutting disk 9 to form a clean- cut chamfer as that part of the cut pipe is rotated on the rollers.

The framework 3 has a telescopic arrangement of tubes 23 and 24 enabling the length of the assembly (between the outermost rollers 4 and 7) to be adjusted as necessary for pipes of differing lengths. The telescopic pipes 23.and 24 can then be fixed in the desired position by screws 25.

The equipment provides an accurate quick cut to the pipe and at the same time provides a chamfer at the desired, and accurate angle. If desired the cutting disk 9 could be in two parts, one with the cutting teeth 14 and the other with the blades 16 or 19. The two parts can then be fixed together to enable differing combinations of disk diameter and width and angle of the chamfer blades 16 or 19 to be achieved.