The present invention relates to cutting tools, in particular but not exclusively, for cutting tubular conduits or pipes.
Plumbing systems have conventionally used copper piping to feed water in water and central heating systems. Copper having become expensive, pipes of plastics material are increasingly used.
Cutting tools for cutting piping have hitherto involved a metallic support carrying a pair of spaced rollers for supporting the pipe to be cut. The support also carries a rotatably supported cutting disc for engaging the side of the pipe opposite that carried by the rollers. A screw mechanism allows the disc to be progressively advanced towards the rollers and into engagement with the pipe. Rotation of the tool about the pipe will create a circular score line in the pipe. An incremental advance of the disc will allow it to bite deeper into the pipe so that on rotation the whole score line is deepened. The process of incrementally advancing the disc and rotating the tool will eventually result in the total severance of the pipe into two lengths.
The tool is relatively expensive and its operation somewhat tedious. Also, when used with pipes of plastics, the pressure exerted by the tool can cause deformation of the pipe.
It is an object of the present invention to provide an improved cutting tool.
According to the present invention there is provided a tool for cutting a cylindrical conduit having a predetermined external diameter, said tool comprising a body having a bore of a diameter substantially equal to said predetermined diameter and extending along a predetermined axis through the body, a slot extending from an external surface of the body to the bore in the general direction of a first plane containing said axis, said slot tapering so that its width progressively diminishes with distance from the external surface of the body to the external circumference of said bore, said width at said external surface of the body exceeding said predetermined diameter, and at said bore being smaller than said predetermined diameter, a cutting blade extending into said bore along a plane extending at right angles to said predetermined axis by an amount exceeding the thickness of the wall of said conduit, the body having a first portion on one side of the slot which is generally rigid and inflexible and a second portion on the other side of the slot which is resilient and flexible whereby the progressive insertion of a conduit into the bore along the slot will cause the second portion initially to flex away from the first portion until the conduit enters the bore where after the first portion will resile and urge the conduit against the blade, so that relative rotation between the tool and conduit about the predetermined axis will result in the severing of the conduit.
A cutting tool embodying the present invention, will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:
a to 3e are a series of views of the tool of
The tool of
Each half portion 2A, 2B has a radially inwardly extending slot 12 which extends from the outer circumference of the portion to the outer circumference of the bore 10. The slot 12 is tapered and reduces in width with distance from the outer circumference of the portion towards the bore 10. The width of the slot 12 at the outer circumference is larger than the outer diameter of the pipe to be cut by preferably up to 10% and at the outer circumference of the bore the width of the slot is smaller than the diameter of the pipe to be cut by, advantageously, at least 10% but preferably by at least 5% sufficient to retain the pipe during cutting.
While the slot 12 extends generally radially inwardly, one side wall 16 has at least a portion adjacent the point at which it joins the bore 10, that is tangential to the bore 10 at that point. The segment 18 of the portion 2A (hereinafter referred to as ‘the first segment’) that is in part defined by the side wall 16, is solid and is generally inflexible. The remaining segments 19 of the portion 2A (hereinafter referred to as ‘the second segment’) is hollow and has a relatively thin outer wall 20 and a relatively thin radially inwardly displaced inner wall 22. This allows the distal end of the second segment 19 to flex away from the distal end of the first segment 18 and resile under its inherent resilience back again.
The opposite side wall 26, of the slot 12 to the side 16, extends generally radially inwardly to intersect the bore 10 substantially at right angles to its circumference and so forms a nose 30 at the junction of the slot and bore that faces the side wall 16. When the tool is in a relaxed state, the nose 30 is spaced from the side wall by a distance less than the diameter of a pipe to be cut. However, when a pipe is placed on the side wall 16 and displaced inwardly along the side, it will engage the nose 30 and through flexture of the inner and outer walls 20 and 22, will be displaced away from the side wall 16 until the pipe passes into the bore at which point the nose will snap back towards its relaxed state to hold the pipe captive in the bore 10.
When the pipe initially engages the bore 10, it initially engages the blade and so is held from being fully accommodated in the bore 10. The nose 30 will at this point still be acting under the resilience of the walls 20 and 22 to urge the pipe against the blade. Any rotation of the tool relative to the pipe will cause the blade to progressively score the pipe under the pressure applied by the nose until the blade has cut through the wall of pipe whereupon the pipe is fully accommodated within the bore but is severed into two parts.
Depending upon the flexibility and resilience of the material used for the two portions 2A and 2B, the nose 30 may be profiled to have a greater or lesser prominence.
The operation of the tool can be more completely and clearly seen from
As shown in
In the second embodiment shown in
Using a specially hardened rotary blade 38 enables the tool to cut more demanding materials such as pipes made of copper.
Instead of a rotary circular blade, a fixed blade having an arcuate profile in the slot similar to that of the rotary blade may be used.
It will be appreciated that while the tool is of a generally cylindrical configuration, it can have other profiles such as ovaloid or cubic.
It will be appreciated that the tool described is intended to cut one size of pipe only. Different sized tools are needed to cut other sizes of pipe.
The body has a knurled outer surface to ease gripping.
The body is preferably made of nylon or other suitable resilient plastic.
With the tools of
As shown in
In the third embodiment, shown in
As shown, such pipes 48 consist of a series of axially spaced peaks 50 and troughs 52 to allow the pipe to be bent, concertina fashion, away from its central axis so that the pipe can follow an arcuate path.
Such pipes need to be cut to length by severing the pipe at right angles to their central axis either in a trough or on a peak. In order to ensure that the cutting blade of the tool is aligned with the desired cutting position, the tool is provided with a radially inwardly extending rib 54 which extends along one side of the slot 12 around the bore 10 and then along the other side of the slot 12. Embedded in and standing proud of the rib is a cutting blade 56.
In operation, the corrugated pipe is inserted into the tool by causing the portions of the rib 54 on opposite sides of the slot to engage the trough located where the pipe is to be cut. Then pressing the pipe to be cut into the bore will cause the cutting blade 56 to engage the pipe. Relative rotation of the pipe against the blade will produce a circular cut around the pipe. Multiple ribs may serve the same purpose. The blade in this embodiment is situated in the centre of a rib but may be located to either side of the guide rib or ribs.
The portion of the cutting blade 56, which projects from the rib 54, may be straight or triangular in profile with the exposed sides of the triangle, one or each, defining a cutting edge. One cutting edge may extend generally radially of the bore while the other cutting edge may extend generally circumferentially at the bore. The two edges extend generally at right angles to each other.
Various flowable and semiflowable materials, particularly in the building trade are traditionally marketed in sealed cartridges. Such cartridges as shown in
The cap 62 supports an outwardly projecting dispensing tube 64 which is externally screw threaded and sealed at its distal end. A dispensing nozzle 66 (see
The nozzle 66 has a cylindrical end portion 68 with an internal screw thread adapted to screw threadedly engage the tube 64 of the cap 62 and a tapered portion 70 extending away from the cylindrical end portion 68 so that both internal and external diameters progressively reduce with distance from the cylindrical end portion 68. The distal end of the tapered portion may be open or sealed.
To make the cartridge ready for use the end of the dispensing tube needs to be severed at right angles to its axis to release the material within the body 58. Also the tapered portion 70 of the nozzle 66 needs to be severed to provide the appropriate size of dispensing orifice from the nozzle. The nozzle is preferably severed along a plane included to the axis of the nozzle to provide a guide surface to guide the direction in which the material is dispensed.
The tools described in
However frequently cartridges of the type described come in two sizes each having a dispensing tube of different diameters.
The tool shown in
The two blades 76 and 78 are preferably spaced equidistantly from outer end faces of the tool.
As shown parts similar to those in
It will be appreciated that the secondary blade 90 can also be incorporated into the other embodiments of the tool described herein.
The recessed location of the secondary blade in a channel provides a degree of protection against the blade harming the user.
Number | Date | Country | Kind |
---|---|---|---|
0802564.5 | Feb 2008 | GB | national |
0817402.1 | Sep 2008 | GB | national |
0820832.4 | Nov 2008 | GB | national |
This application is continuation of pending U.S. application Ser. No. 12/867,015 filed on Aug. 10, 2010, which is a National Phase Patent Application of International Application Number PCT/GB2009/00374 filed on Feb. 10, 2009, which claims priority to British Patent Application Numbers 0802564.5 filed Feb. 12, 2008, 0817402.1 filed Sep. 23, 2008, and 0820832.4 filed Nov. 14, 2008, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
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Parent | 12867015 | Oct 2010 | US |
Child | 13297190 | US |