Plastics pipes of nominal diameter 110 mm or 160 mm are commonly used as waste pipes for carrying waste liquids and storm water to sewers or the like. The pipes are often connected to one another using push fit connectors and are arranged to cooperate with push fit fittings. The connectors and fittings each contain regions of enlarged diameter intended to receive an end part of the pipe, an annular seal member being arranged to form a seal between the pipe and the connector/fitting.

The ends of pipes for use with such connectors or fittings are provided with externally chamfered ends which assist in assembly by permitting relatively easy insertion of the end part of the pipe through the seal member. Where, during installation, a length of pipe is cut, it will be appreciated that the cut end of the pipe is not chamfered. It is known to use a file or other abrasive material to form chamfers at the cut ends of pipes, but this is time-consuming. Rather than form such chamfers, the cut end of the pipe is often forced into a connector or fitting with the risk of damage to the seal member, or the seal member may be removed to simplify assembly, resulting in leakage.

Further, where a length of pipe is cut, difficulties may be experienced in ensuring that the pipe is cut in a plane substantially perpendicular to the axis of the pipe.

According to the present invention there is provided a pipe trimming tool comprising chamfer forming means carried by a mounting arrangement, the chamfer forming means being arranged to remove pipe material from an end region of a pipe upon relative angular movement of the chamfer forming means and the pipe, in use, and a support arrangement arranged to be received within the pipe to guide the movement of the chamfer forming means relative to the pipe.

The chamfer forming means preferably comprises a blade. The blade is conveniently moveable in a radial direction and is conveniently spring biased towards a radially inner position. An adjustment arrangement may be provided to adjust the magnitude of the spring load applied to the blade.

Such a pipe trimming tool is advantageous in that a chamfer can be formed at a cut end region of a pipe, and as a result insertion of the end of the pipe into a connector or fitting is simplified.

The tool may further comprise a sponge or foam insert which, in use, may be impregnated with a suitable lubricant.

Conveniently, the tool further comprises a resilient C-shaped clip having an end lying in a plane substantially perpendicular to an axis of the clip.

The clip can be snapped onto a pipe, in use, and used to form a guide for cutting the pipe. Alternatively, the end of the clip may be used to permit the formation of a guide line upon the pipe for subsequent use in cutting the pipe.

The invention will further be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a pipe trimming tool in accordance with an embodiment; Figure 2 is an exploded perspective view of the tool of Figure 1 with the tool inverted; Figure 3 is a diagram illustrating operation of the tool; and Figure 4 is an exploded perspective view of part of the tool.

The pipe trimming tool illustrated in the accompanying drawings comprises a two-part plastics moulded housing including an upper part 10 and a lower part 12. The lower part 12 is of tubular form including, at its lowermost end, an outwardly extending flange 13. Intermediate its upper and lower ends, the lower housing part 12 is provided with an interior wall 14 of substantially circular form.

It will be appreciated that the lower housing part 12 defines an interior chamber or volume which is accessible from beneath in the orientation illustrated. The volume is closed, in use, by a cap 15 which is arranged to be secured to the lower housing part 12 by means of a bayonet type connection, the cap 15 carrying a foam insert 16 which is impregnated with a suitable lubricant or detergent. Although the cap 15 is arranged to be secured to the lower housing part 12 by means of a bayonet type connection, it will be appreciated that other techniques may be used, for example the cap 15 and lower housing part 12 may be an interference fit or the cap 15 and lower housing part 12 may be arranged to be secured to one another by means of a screw-threaded connection.

A sleeve 17 of tubular form having an inner diameter slightly greater than the outer diameter of the main portion of the lower housing part 12 is held captive between the upper and lower housing parts 10,12 by means of the flange 13. The diameters of the sleeve 17 and the lower housing part 12 are such that the sleeve 17 is free to rotate relative to the housing formed by the upper and lower housing parts 10,12.

The upper housing part 10 is provided with an opening 18 within which an adjustment member 19 is located. The adjustment member 19 is of substantially circular form and is provided with a handgrip 20 arranged to permit angular movement of the adjustment member 19 relative to the upper housing part 10. The sides of the handgrip 20 may be of concave form. A screw-threaded member in the form of a bolt 21 is secured to the adjustment member 19, the bolt 21 extending through the opening 18 of the upper housing part 10 and through an opening 22 provided in the wall 14, a nut located within the volume defined by the lower housing part 12 adjacent the underside of the wall 14 being secured to the bolt 21 to secure the adjustment member 19 to the lower housing part 12. The opening 18 formed in the upper housing part 10 defines a shoulder 23 with which the outer part of the lower surface of the adjustment member 19 is in engagement, and it will be appreciated that as a result, the upper and lower housing parts 10,12 are secured to one another by means of the adjustment member 19.

As illustrated in Figure 2, the underside of the adjustment member 19 is provided with a formation 24 defining a cam slot 25. A slide member 26 is slidable within a slot 27 formed in the underside of the upper housing part 10, the slide member 26 being provided with a tooth or peg 28 which is received within the cam slot 25. The cam slot 25 is shaped such that angular movement of the adjustment member 19 relative to the upper housing part 10 causes the slide member 26 to move in a radial direction within the slot 27.

The slide member 26 is provided with side walls and an end wall 29 which together define a spring chamber. An opening is formed in the end wall 29 through which the shank of a screw-threaded bolt 30 extends, and a spring 31 is held captive between the head of the bolt 30 and the end wall 29. The bolt 30 is in screw-threaded engagement with a blade holder 32 which is slidable within a slot 33 formed in the under surface of the upper housing part 10.

As illustrated most clearly in Figure 4, the blade holder 32 is shaped to define a slot 34 within which a blade 35 is received, the blade 35 being secured in position by means of a screw 36 and washer 37. The blade 35 comprises a square of tool steel material, and the slot 34 is orientated such that, in use, when an end region of a pipe is introduced around the sleeve 17, one of the edges 38 of the blade 35 is presented to the pipe material and acts as a cutting edge. The cutting edge is angled relative to the axis of the pipe to form a chamfer on the pipe, in use. In the event that the cutting edge becomes blunt, then the screw 36 is released and the blade 35 removed. The blade 35 is reintroduced into the slot 34 with a different one of the edges 38 thereof presented to the material of the pipe. It will be appreciated that in such an arrangement, a single blade has eight edges 38 which can act as cutting edges depending upon the orientation of the blade 35.

In order to assist in operating the tool, the upper housing part 10 is provided with a radially outwardly extending arm 39 upon which a handle 40 is mounted. As illustrated in Figures 2 and 3, the slot 33 is formed in the under surface of the arm 39.

In order to avoid tilting of the blade holder 32 and blade 35, in use, the under surface of the upper housing part 10 is conveniently provided with a formation 41 illustrated most clearly in Figure 3 located adjacent the slot 33 and with which a side surface of the blade holder 32 is engagable to give the blade holder 32 additional support.

As illustrated in Figure 3, the tool further comprises a clip 42 which is of part-circular form and is constructed of a resiliently flexible material. The clip 42 is shaped such that in a rest condition, the diameter of the clip 42 is less than that of the outer diameter of the sleeve 17, and thus the clip 42 may conveniently be stored upon the sleeve 17. The clip 42 is designed to be sufficiently flexible that it can be expanded to a degree sufficient to permit the clip 42 to be snap-fitted onto a pipe. The clip 42 is shaped such that when secured upon a pipe as illustrated in Figure 3, a plane containing an end surface of the clip 42 lies substantially perpendicular to an axis of the pipe. In such a condition, the clip 42 may be moved axially upon the pipe to a desired position and then the end surface used to permit the formation of a guideline upon the pipe, for example using a marker pen or pencil or by scoring or scratching a line in the pipe surface.

The clip 42 can then be removed from the pipe and the guideline used to assist in guiding cutting of the pipe. Alternatively, where the clip 42 is constructed of a sufficiently hard-wearing material, the clip 42 may be used directly to guide cutting of the pipe. It will be appreciated, however, that for such use, the clip 42 must be of a sufficiently hard-wearing material to withstand the abrasion which will occur during cutting of the pipe.

Once the length of pipe has been cut, the sleeve 17 of the tool is introduced into the pipe such that the cut end of the pipe lies adjacent the blade 35. The adjustment member 19 is moved angularly to apply a predetermined spring loading to the blade 35 biasing the blade 35 into engagement with the pipe. The magnitude of the predetermined spring loading is selected by selecting the angular position of the adjustment member 19, and the upper housing part 10 is conveniently provided with markings indicating several suitable settings for the adjustment member 19 to apply appropriate spring loadings to the blade 35. Once the appropriate spring loading has been achieved, the pipe is held firm and a load is applied to the handle 40 to cause rotation of the upper and lower housing parts 10,12 relative to the pipe. The sleeve 17 which is received within the pipe is of dimensions sufficient to support the tool to ensure that as the upper housing part 10 is rotated relative to the pipe, the blade 35 moves through a circular path in a plane substantially perpendicular to the axis of the pipe. The movement of the upper housing part 10 causes the blade 35 to shave pipe material from the outer surface of the pipe adjacent its cut end to form a chamfer at the cut end of the pipe. It wi I I be appreciated that as the pipe material is cut away, the blade holder 32 and blade 35 will move under the action of the spring 31 to ensure that the blade 35 remains in engagement with the pipe. Rotation of the upper housing part 10 relative to the pipe continues until the desired chamfer has been formed. Thereafter the pipe is removed from the sleeve 17.

Lubricant or detergent can then be applied to the end region of the pipe by removing the cap 15 from the lower housing part 12 and using the impregnated foam insert 16 to apply lubricant or detergent to the pipe.

The cut end of the pipe is then ready for insertion into a connector or fitting in the usual manner. It will be appreciated that, if desired, the lubricant or detergent could be applied prior to formation of the chamfer.

The mounting of the handle 40 upon the arm 39 gives a leverage effect.

Thus less effort is required in rotating the tool relative to the pipe than would be the case if the handle were not mounted upon an outwardly extending arm. For convenience and comfort, the handle 40 is conveniently rotatably mounted upon the arm 39. It will be appreciated, however, that such mounting is not essential. As the sleeve 17 is rotatable relative to the remainder of the tool, the sleeve 17 can be gripped within the pipe and serves to minimise drag between the pipe and the tool.

These effects combine to give rise to a tool which is relatively easy to operate.