GB2603890A

GB2603890A - Cutter

Info

Publication number: GB2603890A
Application number: GB2020406.1A
Authority: GB
Inventors: Ewels Robert
Original assignee: Thomas Dudley Ltd
Current assignee: Thomas Dudley Ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-08-24
Also published as: GB202020406D0

Abstract

A cutter 105 for a boring device (1, Figure 1) includes a cutting head 151a and a threaded driving portion 150 for engaging receipt within a threaded bore 23 in a housing 10 of the boring device. A shank 151b extends between the cutting head and the driving portion. The shank includes an undercut 155 to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates and advances within the housing. A method of cutting a hole in a pipe includes driving a cutter within a housing such that a cutting head rotates and advances into a wall of the pipe. Swarf wraps around an undercut of a shank of the cutter as it advances. The cutter is retracted with at least part of the swarf wrapped around the shank. The cutting head may include a pair of flanges and a castellated cutting end.

Description

CUTTER

This invention relates generally to cutters, particularly for use in boring devices. More specifically, although not exclusively, this invention relates to cutters for use in pipe boring devices, such as self-tapping ferrule straps, for making a fluid connection through the wall of a pipe. The cutter is also useful for other applications requiring a hole to be bored into the wall of a vessel and/or other applications that will be appreciated by the skilled person.

Self-tapping ferrule straps are generally formed of cast gunmetal and sized to suit a particular pipe diameter. These straps are formed in two, part-circular castings that are wrapped around opposite sides of the pipe and bolted together. Whilst such arrangements are fit for purpose, they are bulky, expensive to manufacture and provide minimal adjustment.

Adjustable self-tapping ferrule straps are also known, which consist of a single casting to which a steel strap is secured at one side. The strap has a portion near its free end having spaced holes for selective engagement with a fastener on the other side of the casting. This arrangement can accommodate a wide array of pipe sizes, but the free end of the strap can present a safety hazard.

W02016083786 seeks to remedy this problem by providing a strap with a pair of strap portions connected together at a first of their ends, wherein a first strap portion has a slot and the second strap portion has hooks spaced along its length. When the strap is wrapped around a pipe, the first strap portion overlaps the second strap portion such that one of the hooks is received in the slot, extends through the first strap portion and is in engagement with the end of the slot.

A cutter having an external thread is then rotated within a threaded bore in a housing sealingly mounted to the pipe by the strap. The cutter also includes a tubular cutting portion that bores a hole into the pipe as the cutter advances. The tubular cutting portion retains a plug of material when the cutter passes through the pipe wall. When the cutter is retracted, the plug remains captivated within the tubular portion.

The applicant has observed that the use of such cutters can be problematic with relatively thick pipes.

It would therefore be desirable to provide a boring device that mitigates the issues with known cutters and boring devices. It would also be desirable to provide a cutter and boring device that is able to accommodate a greater range of applications.

Accordingly, a first aspect of the invention provides a cutter, e.g. for use in a boring device, the cutter comprising a cutting head and a shank with an undercut to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates.

The inventors have observed that the aforementioned, conventional tubular cutters can lo become wedged or stuck, thereby failing to bore fully into the pipe. This compromises the integrity of the pipe, requiring expensive and disruptive corrective action. The use of a cutter with a cutting head and an undercut shank avoids these issues, whilst still enabling the removal of the material on retraction of the cutter. This inhibits the swarf from entering the pipe, and avoids contaminating the fluid passing therethrough.

The cutter may comprise a driving portion, which may be threaded or may include a thread. The shank may extend between the driving portion and the cutting head. The driving portion may configured for engaging receipt within a threaded bore in a housing of a boring device. The undercut of the shank may be configured to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates and advances within the housing.

Another aspect of the invention provides a cutter, e.g. for a boring device, the cutter comprising a cutting head, a threaded driving portion for engaging receipt within a threaded bore in a housing of the boring device, and a shank extending between the cutting head and the driving portion, wherein the shank comprises an undercut to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates and advances within the housing.

The cutter may comprise a rotation axis or rotational axis. The cutting head may be flat and/or may extend laterally, transversely and/or radially. The cutting head may comprise one or more cutting edges, which may extend laterally, transversely and/or radially. The cutting head may comprise one or more, e.g. a pair of, flanges. The flange(s) may extend laterally, transversely and/or radially of the rotational axis.

The cutter or cutting head may comprise a cutting end. The cutting end may be or extend along the flanges. The cutter or cutting head or cutting end may comprise one or more cutting elements. The cutter or cutting head or cutting end may comprise one or more spaces, voids or gaps, hereinafter voids. The cutting elements may be spaced and/or the voids may be located between the cutting elements. The cutting elements may be spaced by the voids. Adjacent pairs of cutting elements may be spaced by a respective one of the voids.

The cutting elements and voids may alternate. The cutter or cutting head or cutting end io may comprise alternating cutting elements and voids. The cutter or cutting head or cutting end may be castellated. The cutting end may comprise a castellated cutting end, which may be described by alternating cutting elements and voids. The cutting head may be asymmetrical.

The rotational sweep of each cutting element on one of the flanges may overlap the rotational sweep of one of the voids, e.g. a corresponding one of the voids, on the other flange. One of the voids on one of the flanges may be located at the lateral or radial end thereof. The distance between the rotational axis of the cutter and each cutting element on one of the flanges may correspond substantially to the distance between the rotational axis of the cutter and one of the voids, e.g. the corresponding void, on the other of the flanges.

The aforementioned features provide continuous, multiple swarf ribbons that coil around the shank of the cutter reliably as the cutter is advanced. This will facilitate removal and/or retention of the waste material, thereby providing substantial advantages that would be evident to the skilled person.

The cutter or cutting head may comprise three or more cutting elements and/or three or more voids, for example three or more corresponding three or more voids. The cutter or cutting head may comprise four or more cutting elements and/or four or more voids, for example four or more corresponding three or more voids.

The width of at least one of the cutting elements may be greater than the width of at least one, e.g. its corresponding, void. The width of each cutting element may be greater than the width of its corresponding void. The width of each cutting element may between 1% and 30% greater than the width of its corresponding void. Preferably, the width of each cutting element may between 2% and 25% greater than the width of its corresponding void. More preferably, the width of each cutting element may between 5% and 15% greater than the width of its corresponding void.

Additionally or alternatively, the axial depth of each void may be less than its width. The axial depth of each void may be at least 20% of its width. Preferably, the axial depth of each void is between 50% and 90% of its width. In some specific examples, the axial depth of each void is between 1mm and 2mm.

At least part of the cutting head may be substantially flat. The cutting head, e.g. the entire cutting head, may be substantially flat. At least part of the shank may be substantially flat. The shank, e.g. the entire shank, may be substantially flat. The undercut may extend from the cutting head toward the threaded driving portion. The shank, for example the flat portion of the shank, may taper, e.g. toward the cutting head.

The undercut of the shank may comprise a necked portion of the shank. The portion of the shank comprising the undercut may be substantially flat, in which case the undercut may comprise narrowed or necked portion and/or may be described by a cutout on each side thereof. The shank may comprise a shoulder, which may be between the undercut and the threaded driving portion. The or a further shoulder may be between the undercut and the cutting head. The or at least one or each shoulder of the shank may be for inhibiting the passage of swarf into the threaded driving portion.

The shank may have a cross-section, which may comprise a radial cross-section and/or may be perpendicular to the rotational axis. The cross-section may be polygonal. The cross-section may be concave polygonal. The cross-section may be in the form of a concave polygon.

The shank may have a plurality, e.g. two or three or four or more, fins. The or at least one or each fin may comprise radial fin and/or may be perpendicular to the rotational axis and/or may extend along the rotational axis. The or at least one or each fin may comprise a shoulder, e.g. between the undercut and the threaded driving portion. The or at least one or each shoulder may be for inhibiting the passage of swarf into the threaded driving portion.

At least part of the shank may comprise a cruciform-shaped cross-section, e.g. radial cross section. The shank may have four radial fins describing a cruciform-shaped radial cross-section. The cutting head may be substantially contiguous with a first pair of opposed radial fins of the shank. Each of a second pair of opposed radial fins of the shank may comprise a lip, which may be aligned with a base of the cutting head and/or with the shoulder between the undercut and the cutting head.

The cutter or shank may comprise a stop, which may be configured to limit the depth to which the cutter may penetrate, in use, into the pipe or substrate. The cutter or shank may io comprise a step, which may provide the stop. The stop or step may comprise a composite stop or step. The stop or step may be provided in part by each of the fins.

The or each cutting element may comprise a cutting edge. The culling edge(s), e.g. at least one or more or all of the cutting edges, may be substantially perpendicular or orthogonal to the or a rotational axis of the cutter, e.g. for making a blind bore.

The or each cutting edge may comprise or be described by a bevelled edge. The or each bevelled edge may be described in part by a leading face, which may be parallel to the rotational axis of the cutter. The or each bevelled edge may be described in part by a trailing face, which may extend at an angle, e.g. a bevel angle or bevelled angle, relative to the leading face. As used herein, the terms leading and trailing refer to the relative position of the face in relation to the intended direction of rotation of the cutter.

The leading face on one of the flanges may be on a first side of the cutting head. The leading face on the other of the flanges may be a second side of the cutting head. The cutting element(s) on the flanges are bevelled in opposite directions. The culling elements on a first of the flanges may be bevelled in a first direction and/or the cutting elements on a second of the flanges may be bevelled in a second direction. The second direction may be opposite the first direction.

The threaded driving portion comprises a driving feature, e.g. a polygonal driving feature, for engagement with a driving tool. The driving feature may comprise a plug, e.g. for engaging a corresponding socket in a driving tool. Alternatively, the driving feature may comprise a socket, recess, keyway, projection or key, e.g. for engaging a corresponding plug in a driving tool.

Another aspect of the invention provides a boring device comprising a cutter as described above and a housing with a threaded bore within which the driving portion of the cutter is engagingly received.

The device may comprise a strap, e.g. for mounting the device to a pipe. The housing may comprise a tubular body with a base for engaging a pipe. The bore may extend from the base into the tubular body.

io Yet another aspect of the invention provides a boring device comprising a housing and a strap for mounting the boring device to a pipe, the housing comprising a tubular body with a base for engaging a pipe, a threaded bore extending from the base into the tubular body and a cutter received within the threaded bore, the cutter comprising a threaded driving portion for engaging the threaded bore of the housing, a cutting head and a shank extending between the driving portion and the cutting head, wherein the shank comprises an undercut to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates and advances within the housing.

The threads of the housing and cutter may cooperate such that rotation of the cutter causes it translate along the bore. The housing may comprise a transverse hole extending from the threaded bore to a fitting for connection with an off-take pipe.

Alternatively, the housing may comprise a fluid passageway. The fluid passageway may surround, e.g. at least partially surround, the bore. The housing may comprise an outlet, e.g. for connecting the fluid passageway with an off-take pipe. The base may comprise one or more transfer passages. The or at least one or each of the transfer passages may be external of the bore. The or at least one of the transfer passages may provide, e.g. in use, fluid communication between the fluid passageway and a hole formed in the pipe by the cutter.

The device or housing or inner part may comprise an opening, which may be at the or an opposite end to the base, for example the second end, which may be for inserting a tool to drive the cutter.

The boring device may form part of a kit of parts and/or may comprise a further or second cutter. The further or second cutter may include a threaded driving portion, e.g. for engaging receipt within the threaded bore in the housing. The further or second cutter may comprise a tubular cutting member. The tubular cutting member may have an annular or part-annular or segmented annular cutting edge.

The further or second cutter may comprise a first end, e.g. a driving end, and/or a second end, e.g. a cutting end. The first end may comprise or be provided by the threaded driving portion. The cutter may comprise a substantially constant size or diameter. The first end to may have substantially the same diameter or cross-section as the second end. The cutter or first end thereof may comprise a driving feature, e.g. a polygonal driving feature, for engagement with a driving tool. The driving feature may comprise a plug, e.g. for engaging a corresponding socket in a driving tool. Alternatively, the driving feature may comprise a socket, recess, keyway, projection or key, e.g. for engaging a corresponding plug in a driving tool.

The cutter or second end thereof may comprise a tubular cutting member having a sharp and/or slanted or sloped edge. The cutter or tubular cutting member may comprise a pair of substantially axial slots, which may be slanted relative to the longitudinal axis of the cutter and/or which may describe or delineate or divide the tubular cutting member into a pair of cutting blades.

The bore and/or the cutter may comprise a thread having a pair of flanks, for example a first flank and a second flank. The angle between the first flank and an axis, e.g. longitudinal axis, of the bore or cutter may be different to, for example steeper than, the angle between the second flank and the axis. The first flank of the bore may face the base, while the second flank of the bore may face away from the base. The second flank of the cutter may face a cutting end thereof, while the first flank of the bore may face away from the cutting end.

The first flank of the cutter may engage the first flank of the bore and/or the second flank of the cutter may engage the second flank of the bore. The first flank may comprise a leading flank and/or the second flank may comprise a trailing flank. The trailing flanks may be steeper than the leading flank, for example to resist inadvertent retraction of the cutter into the bore and/or to improve the stress distribution along and/or across the threads. As used herein, the terms leading and trailing refer to the direction of movement of the cutter as it bores, in use, a hole in the pipe.

The device or base may comprise a pipe facing surface, which may include an inlet chamber. At least one or the transfer passage may fluidly connect the inlet chamber to the fluid passageway. The inlet chamber may be configured to allow or facilitate the flow of fluid from a pipe into the transfer passage(s), for example when the cutter is retracted from the pipe.

io The pipe boring device may be configured such that at least part of a pipe-facing side or surface of the base stands proud, in use, of the pipe, e.g. to provide the inlet chamber. The inlet chamber may be provided at least in part by a recess formed in the base. The or a pipe-facing side or surface of the base may comprise the recess. At least a portion of the recess may comprise an annular recess, for example surrounding or circumscribing the is bore.

The device may comprise a sealing means or seal extending about the inlet chamber. The inlet chamber may be provided at least in part by the sealing means or seal. The sealing means or seal may stand proud of and/or protrude from the base, e.g. such that the base is spaced, in use, from a pipe to which the device is mounted and/or so as to describe at least part of the inlet chamber. The sealing means or seal may extend about the bore and/or the transfer passage(s) and, if present, the recess. The seal may comprise an annular seal. The annular seal may be received or seated within the annular recess The device may comprise a plurality of transfer passages, which may be spaced, e.g. circumferentially spaced, about the bore. The transfer passages may provide a segmented flow path, e.g. a segmented or composite annular flow path. The transfer passages may at least partially surround the bore and/or may be separated by webs.

The housing may comprise an inner part, which may comprise a stem, and/or an outer part, which may comprise a banjo fitting. The outlet may comprise a push-fit connector. The inner part may comprise the bore and/or the base. The base may comprise a saddle and/or may be saddle-shaped. The inner part may comprise an annular recess, which may describe part of the fluid passageway. The transfer passage(s) may extend from the or a pipe-facing side of the base to the annular recess. The inner part may comprise one or more, e.g. a pair of, sealing annuli. The annular recess may be described between the sealing annuli. The transfer passage(s) may extend through the base. The outer part may be arranged to receive the inner part, for example to describe the fluid passageway therebetween.

The inner and outer parts may be connected, e.g. sealingly connected, by sealing means, which may be annular and/or circumferential. The sealing means may comprise one or more, e.g. a pair of, seals or annular seals. The or at least one of the seals may be received in a recess or groove, e.g. a circumferential groove, in or of the inner or outer part. The inner part may comprise one or more, e.g. a pair of, sealing annuli. The or each sealing annulus may protrude or project from the inner part, e.g. the or a stem or stem portion thereof. The or each sealing annulus may comprise the recess or groove.

The pair of sealing annuli may be on either side of the fluid passageway. A first sealing annulus may be on or located on a first side of the fluid passageway. A second sealing annulus may be on or located on a second side of the fluid passageway, e.g. opposite the first side. The pair of seals may be received in respective recesses either side of the fluid passageway. A first seal may be received in a recess on a first side of the fluid passageway. A second seal may be received in a recess on a second side of the fluid passageway, e.g. opposite the first side. The recess(es) and/or sealing annuli may be circumferential and/or the seal(s) may comprise circumferential seals. The or at least one of the seals may comprise an 0-ring or a gasket.

The device may comprise an end cap, which may be mounted to the housing or inner part, e.g. for retaining the outer part thereon. The end cap may be retained on the housing or inner part, for example by a bayonet fitting. The base may be at a first end of the housing or inner part. The end cap may be mounted to a second end of the housing or inner part.

The inner part may be formed of a stronger and/or more rigid material than the outer part. The inner part may be formed of metal, e.g. gunmetal. Alternatively, the inner part may be formed of an engineered plastics material. Additionally or alternatively, the outer part may be formed of metal, e.g. gunmetal, but is preferably formed of an engineered plastics material.

The device or housing or inner part may comprise a shoulder, which may be described between the bore and the opening. The device or housing or inner part may comprise a seal means, e.g. an annular seal means, which may be captivated between the shoulder and the cutter. The seal means may comprise a seal or washer or gasket.

The strap may be for securement around a pipe and/or to enable a hole to be bored into the pipe. The strap may comprise first and second strap portions, which may be connected together, e.g. at a respective first of their ends. One of the strap portions may comprise a receptacle within which the housing is received. The receptacle may comprise at least one, e.g. a pair of opposed, retaining tab(s), which may engage a notch or respective notches in the housing, e.g. to retain the boring means within the receptacle. The strap portions may io be connected together by connection means, for example adjustable connection means, which may be for adjusting the relative position of the connected first ends. The strap portions may be pivotally connected together by the connection means.

The connection means may comprise screw threaded adjustment means, e.g. for selectively drawing the strap portion ends together. The connection means may comprise a screw threaded fastener engaging a pair of pins. Each strap portion may comprise a loop, e.g. at or adjacent its connected end, with one of the pins rotatably received therein. Each loop may comprise a circumferential slot, for example through which the fastener extends, such as to enable the strap portions to pivot relative to one another.

The first strap portion may comprise a recess, aperture or slot, which may be at or adjacent a second, free end thereof. The second strap portion may comprise one or more projections or hooks, which may be spaced along its length. The strap may be configured to be wrapped, in use, around a pipe with the first strap portion overlapping the second strap portion, for example wherein the or one of the projection(s) or hook(s) is received in the recess, aperture or slot and may be in engagement therewith. The projection(s) or hook(s) may extend through the first strap portion and/or be in engagement with the end of the recess, aperture or slot.

The strap may define an opening that is at least partially dependent upon which of the projections or hooks is in engagement with the recess or aperture. When the first strap portion overlaps the second strap portion, the second strap portion may be between the first strap portion and the pipe. The first strap portion may comprises a pair of slots. The second strap portion may comprise two or more hook pairs. Each hook pair may be spaced along the length of the second strap portion, for example such that the strap defines an opening that is dependent upon which of the hook pairs is in engagement, in use, with ends of the slot pair.

The strap portions may be formed from sheet material, e.g. sheet metal or sheet steel. The or each projection or hook may comprise a deformed portion of sheet material. The device may comprise a self-tapping ferrule strap.

Another aspect of the invention provides a kit of parts for assembly into a boring device, for example a boring device as described above. The kit may comprise the housing and at to least one of the cutters.

Another aspect of the invention provides a kit of parts for assembly into a pipe boring device, e.g. as described above, the kit comprising a first cutter, a housing and a second cutter, the first cutter comprising a cutting head and a shank with an undercut to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates, the second cutter comprising a threaded driving portion and a tubular cutting member, the housing comprising a tubular body with a base for engaging a pipe and a threaded bore extending from the base into the tubular body, wherein the housing is configured to receive the first cutter in the threaded bore for cutting a blind bore in a pipe and to receive the second cutter in the threaded bore for cutting through the base of the blind bore to penetrate the wall of the pipe.

The kit may comprise the inner part and/or the outer part of the housing. The kit may further comprise the strap, for example the first and second strap portions.

Another aspect of the invention provides a method of cutting a hole in a pipe, the method comprising: driving a cutter within a housing mounted to the pipe such that a cutting head rotates and advances into a wall of the pipe to form a swarf that wraps around an undercut of a shank of the cutter connected to the cutting head as the cutter advances; and retracting the cutter with at least part of the swarf wrapped around the shank.

The method may comprise retracting the cutter before the cutting head penetrates through the wall of the pipe, thereby to provide a blind bore in the wall of the pipe. The method may comprise replacing the cutter with a second cutter having a tubular cutting member. The method may comprise driving the second cutter within the housing such that the tubular cutting member cuts an annulus from a base of the blind bore through the wall of the pipe.

The method may comprise retracting the second cutter to open fluid communication between the pipe and an off-take pipe.

For the avoidance of doubt, any of the features described herein apply equally to any aspect of the invention. For example, the boring device or kit of parts may comprise any one or more features of the cutter relevant thereto or vice versa. Similarly, the method may comprise any one or more features or steps relevant to one or more features of the cutter or the boring device or kit of parts or vice versa.

io Another aspect of the invention provides a computer program element comprising and/or describing and/or defining a three-dimensional design, e.g. of the cutter described above or an embodiment thereof. The three-dimensional design may be for use with a simulation means or an additive or subtractive manufacturing means, system or device.

is The computer program element may be for causing, or operable or configured to cause, an additive or subtractive manufacturing means, system or device to manufacture the cutter described above or an embodiment thereof. The computer program element may comprise computer readable program code means for causing an additive or subtractive manufacturing means, system or device to execute a procedure to manufacture the cutter described above or an embodiment thereof A yet further aspect of the invention provides the computer program element embodied on a computer readable medium.

A yet further aspect of the invention provides a control means or control system or controller comprising the aforementioned computer program element or computer readable medium.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible.

For the avoidance of doubt, the terms "may", "and/or", "e.g.", "for example" and any similar term as used herein should be interpreted as non-limiting such that any feature so-described need not be present. Indeed, any combination of optional features is expressly envisaged without departing from the scope of the invention, whether or not these are expressly claimed. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

lc) Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a section view of the pipe boring device according to the prior art; Figure 2 is a perspective view of a cutter according to an embodiment of the invention; Figure 3 is an enlarged view of the cutting portion of the cutter of Figure 2; Figure 4 is a plan view of the cutter of Figures 2 and 3; Figure 5 is an end view of the cutter of Figures 2 to 4 showing the rotational sweep of one of the cutting elements; Figure 6 is a side view of the cutter of Figures 2 to 5; Figure 7 is an exploded perspective view of a pipe boring device according to another example, incorporating the cutter of Figures 2 to 6; Figure 8 is a perspective view of the inner part of the housing of the boring device of Figure 7; Figure 9 is a perspective view of the inner part of Figure 8 from below; Figure 10 is a perspective view of the pipe boring device of Figure 7 shown in an assembled condition; Figure 11 is a perspective view of a cutter according to another embodiment of the invention; and Figure 12 is an enlarged view of the cutting portion of the cutter of Figure 2.

Referring to the Figure 1, there is shown a boring device 1 in the form of a self-tapping ferrule strap 1 according to the prior art, which is to be wrapped around a pipe (not shown). The device 1 includes a housing 10, which includes an inner part 2, an outer part 3 and an io over cap 4. The inner part 2 threadedly receives a cutter 5 for boring a hole into a pipe (not shown). The device 1 also includes an outer strap portion 6 and an inner strap portion 7, which are connected together by a connector 8.

The inner part 2 is similar to that shown in W02016083786, the contents of which are incorporated herein by reference. More specifically, the inner part 2 includes a saddle portion 20, an intermediate portion 21 and a stem portion 22 with a threaded axial bore 23 extending through all three portions 20, 21, 22.

The saddle portion 20 extends outwardly from the intermediate portion 21 to provide a shoulder 24 and includes a curved bottom surface 25 shaped to conform the outer surface of the pipe (not shown), which lower surface 25 has an 0-ring seal 25a received in a circular groove surrounding the bore 23 for sealing against the pipe (not shown). The intermediate portion 21 is cylindrical in shape, projects upwardly from the shoulder 24 of the saddle portion 20 and includes a pair of notches 26. The stem portion 22 includes an external thread 27 extending along part of its length from its upper end, a transverse or radial bore 28 through a lower part extending through and in communication with the axial bore 23 and radial flanges, one of which is above and another below the radial bore 28.

The outer part 3 is in the form of a banjo fitting 3, which includes an annular portion 30 that surrounds the stem portion 22 of the inner part 2, a radial spigot 31 projecting from one side of the annular portion 30 and a push fit assembly 32 threadedly secured to the radial spigot 31. The radial spigot 31 includes an internal step that receives an annular seal 33 and a top hat-shaped seal retainer 34 of the push fit assembly 32.

The push fit assembly 32 also includes a tapered, split clamp ring 35 captivated between the seal retainer 34 and a push fit cap 36 threadedly secured to the radial spigot 31. The push fit assembly 32 functions in a known manner by allowing a pipe (not shown) to be inserted into an open end of the push fit cap 36 to a position in which the annular seal 33 seals against an outer surface thereof, wherein removal of the pipe (not shown) is inhibited by the cooperation between the tapered, split clamp ring 35 and a tapered facing surface of the push fit cap 36.

The annular portion 30 of the outer part 3 includes an inwardly facing lip 37 at its lower end io and an internal step 38 at its upper end. The lip 37 includes an internal step in its lower surface within which is received an annular seal 39a. The outward step 38 also receives an annular seal 39h.

The over cap 4 includes a first, closed end 40 with a hole 41 through its thickness that is covered by a cap member 42. The over cap 4 also includes an internal bore 43, part of which is threaded, and an outer flange 44 adjacent its open end. The over cap 4 is mounted to the inner part 2 such that the threaded portion of the internal bore 43 engages the external thread 27 of the stem portion 22.

The annular portion 30 of the outer part 3 is captivated between the over cap 4 and the intermediate portion 21 of the inner housing part 2. More specifically, the open end of the over cap 4 engages the annular seal 39b in the outward step 38 at the upper end of the annular portion 30 and urges the annular seal 39a received in the internal step of the lip 37 at its lower end against the end of the intermediate portion 21 adjacent the lower radial flange of the inner part 2. This arrangement provides a compression, face seal-type sealing arrangement that is typical in such bayonet fittings. In addition, an annular sealing washer 45 is captivated and sealing compressed between the closed end 40 of the over cap 4 and the upper end of the inner part 2.

The inner part 2 also receives a self-tapping ferrule insert or cutter 5, which includes an enlarged head 50 at a first end and a tubular cutting member 51 projecting from the head 50. The head 50 is threaded externally and includes a hexagonal socket for receiving a hexagonal tool (not shown) to drive the cutter 5 in use. The tubular cutting member 51 includes a pair of substantially axial slots, which are slanted slightly relative to the longitudinal axis of the cutter Sand divide the tubular cutting member 51 into a pair of cutting blades. Each cutting blade of the cutting member 51 has a sharp, part-circumferential free edge that is slanted to provide a cutting edge in the usual way.

In use, the cap member 42 of the over cap 4 is removed to reveal the hole 41. A hexagonal removal tool (not shown) is inserted into the hole 41 and into the hexagonal socket 53 of the cutter 5. The tool (not shown) is rotated to drive the cutter 5 down to cut into the pipe (not shown). The tool (not shown) is then rotated in reverse to withdraw the cutter 5 out of the hole bored in the pipe (not shown). As the cutter 5 is withdrawn, fluid flows from the pipe (not shown) into the clearance between the undersized tubular cutting member 51 and io the threaded axial bore 23 of the inner part and out of the radial bores 28. Further retraction of the cutter 5 reduces the restriction of flow therepast until the cutter 5 is fully retracted. In the fully retracted position, the head 50 of the cutter 5 seals against the sealing washer 45 to fully seal the device 1.

Turning now to Figures 2 to 6, there is shown a cutter 105 according to the invention. The cutter 105 can be used as a pre-cutter in the boring device 1 of Figure 1, which can be particularly useful when boring a hole in a relatively thick walled pipe (not shown).

The cutter 105 has a first, threaded end portion 150 with a cutting member 151 projecting therefrom. The first end 150 and cutting member 151 have a common rotational axis C, which is shown in Figures 4 and 6. The first end 150 of the cutter 105 includes an external thread 152 and a hexagonal socket 153 for receiving a hexagonal tool (not shown) to drive the cutter 105 in use.

The cutting member 151 is generally flat, being wider than it is thick, the width and thickness directions being perpendicular to the rotational axis C. The cutting member 151 therefore has opposed major surfaces in the width direction and opposed sides in the thickness direction. The cutting member 151 has a cutting head 151a at its end, and a wedge-shaped shank 151b between the cutting head 151a and the fist end portion 150 of the cutter 105.

The thickness of the shank 151b reduces from the first end portion 150 towards the cutting head 151a. A filleted shoulder is provided at the point where the shank 151b adjoins the first end portion 150 of the cutter 105. The thickness of the cutting head 151a is substantially constant. The width of the shank 151b is substantially the same as, or is less than, the minor diameter of the external thread 152. The cutting head 151a includes a castellated cutting end, which defines the second end of the cutter 105.

The shank 151b of the cutting member 151 has undercuts 155 located along each of its lateral sides. Each undercut 155 is spaced from the first end portion 150 of the cutter 105 and extends to the cutting head 151a. The section of the cutting head 151a between the undercuts 155 and the second end of the cutter 105 has a width substantially the same as the maximum width of the shank 151b, to provide a flanged shaped cutting head 151a. Each undercut 155 is rectangular in shape, with filleted internal corners.

The end of the cutting head 151a is square to the rotational axis C in the width direction. The castellated end provides four cutting elements in the form of cutting teeth 154a, 154b, 154c, 154d, with two cutting teeth 154a, 154b and 154c, 154d on either side of the rotational axis C, in the width direction. Each cutting tooth 154a, 154b, 154c, 154d has an end surface, corresponding to a segmented end surface of the cutter 105. The cutting teeth 154a, 154b, 154c, 154d are of substantially the same thickness as the cutting head 151a and all have substantially the same width.

The end surface of each cutting tooth 154a, 154b, 154c, 154d is angled to provide an acute angle or bevel between one major surface of the cutting head 151a, and an obtuse angle with the other major surface of the cutting head 151a. The cutting teeth 154a, 154b on a first side of the rotational axis C are acutely angled, or bevelled, relative to one of the major surfaces the cutting member 151 and the cutting teeth 154c, 154d on a second side of the rotational axis C are acutely angled, or bevelled, relative to the other major surface the cutting member 151. The acute angles, or bevels, provide cutting edges which are perpendicular to the rotational axis C. Other configurations of cutting elements 154a, 154b, 154c, 154d are also envisaged.

The cutting teeth 154a, 154b, 154c, 154d are spaced from one another other to provide voids V therebetween. A void V is also included at the lateral end of the first side of the cutting head 151a, beyond the first cutting tooth 154a. The voids V are substantially cuboidal, with curved sides corresponding to a blend radius between each adjacent cutting tooth 154a, 154b, 154c and the root of the cutting head 151a. The depth of each void V is less than its width and is typically between 1 mm and 2 mm.

The spacing between adjacent cutting teeth 154a, 154b, 154c, 154d, corresponding to the width of the void V, is less than the width of the cutting teeth 154a, 154b, 154c, 154d. The As a result of the void V at the end of the first side of the cutting head 151a, the first cutting tooth 154a is spaced from that end, whereas there is no such void V at the end of the second side of the cutting head 151a, beyond the fourth cutting tooth 151d. Accordingly, the cutting teeth 154a, 154b on the first side of the cutting head 151a mirror the voids Von the second side of the cutting head 151a. Similarly, the cutting teeth 154c, 154d on the second side of the cutting head 151a mirror the voids V on the first side of the cutting head 151a.

In use, the cutter 105 may be used as a pre-cutter for the boring device 1 of Figure 1. In order to pre-cut an initial portion of a hole in a pipe, the inner part 2 of the housing 10 is mounted to a pipe and secured thereto with the strap 6, 7, but with the banjo fitting 3 and over cap 4 omitted. The cutter 105 is inserted, cutting head 151a first, into the threaded axial bore 23 of the inner part 2.

When the cutter 105 is rotated about the rotational axis C, using the hexagonal tool (not shown) received in the hexagonal socket 153, the threaded engagement of the external thread 152 and the bore 23 drives the cutter 105 in an axial direction. In this example, rotating the cutter 105 in a clockwise direction drives the cutter 105 in a cutting direction.

The bevelled edges of the cutting teeth 154a, 154b, 154c, 154d lead when the cutter 105 is rotated in a clockwise direction, providing a cutting function to cut a blind bore.

Each cutting tooth 154a, 154b, 154c, 154d has a rotational sweep which corresponds to the rotational sweep of a corresponding one of the voids V on the opposite lateral side of the cutting head 151a. The rotational sweep 157 of the fourth cutting tooth 154d is shown as a shaded annulus bounded by dashed lines, in Figure 5. As the cutting teeth 154a, 154b, 154c, 154d are wider than the voids, their rotational sweeps overlap with one another. The overlapping rotational sweeps provide a complete, circular coverage of the cutting medium.

This, segmentation of the cutting surface is beneficial because each cutting tooth 154a, 154b, 154c, 154d cuts a continuous string of swarf (not shown). As the length of the swarf string increases, it wraps around the shank 151b. The undercuts 155 contain the swarf therein. By containing the swarf in the undercuts 155, the swarf does not interfere with the external thread 152, and facilitates removal. The filleted shoulder between the cutting member 151 and the first end portion 150 of the cutter 105 also prevents swarf from interfering with the thread.

Once a predetermined blind bore depth has been reached, the cutter 105 is retracted along the threaded axial bore 23 of the inner part 2 of the housing 10. The swarf retained around the shank 151b within the undercuts 155 is retracted together with the cutter 105, before inserting the cutter 5 of the prior art. The banjo fitting 3 and over cap 4 are then assembled over the inner part 2, and the final portion of the bore is cut as described above.

io Another advantage of using the cutter 105 of the invention in this way, is that the majority of the bore drilled in the pipe can have a larger diameter, which facilitates simultaneous insertion of a sleeve into the bore. This can be particularly useful for applications involving thick barrier pipes, which include a laminated wall. These and other advantages will be appreciated by the skilled person.

Turning now to Figure 7, there is a shown a boring device 100 according to another example, which is particularly suited to using the cutter 105 as the sole cutter for boring a hole in a pipe. The boring device 100 in this example includes a housing 101 having an inner part 102, an outer part 103 and an end cap 104. The inner part 102 threadedly receives the cutter 105 for boring a hole into a pipe (not shown). The device 100 also includes an outer strap portion 106 and an inner strap portion 107, which are connected together by a connector 108. A sealing washer 156 is captivated between the first end 150 of the cutter 105 and a shoulder 122b of the inner part 102.

The inner part 102, shown more clearly in Figures 8 and 9, includes a base 120 with a stem 121 projecting therefrom, a castellated or splined end 122 and a threaded axial bore 123 open through the base 120 and extending to a hole 122a through the splined end 122. The diameter of the hole 122a is smaller than that of the threaded axial bore 123, thereby providing a shoulder 122b.

The base 120 includes a saddle portion 124 projecting outwardly in a similar manner to the saddle portion 20 of the boring device 1 of the prior art, but with differences that will be apparent from the present disclosure. The base 120 also includes a first sealing annulus 125 spaced from the saddle portion 124 and six transfer passages 126 surrounding the axial bore 123 and providing a segmented annular flow path therearound.

The saddle portion 124 also includes first and second recesses 124a, 124b in its lower surface. The first recess 124a is substantially cylindrical and coincides with the outer dimension of the transfer passages 126 to describe an inlet chamber 124a. The second recess 124b surrounds the first recess 124a and receives an 0-ring seal 124c for sealing against the pipe (not shown).

The first sealing annulus 125 is in the form of a flange projecting outwardly of the base 120 and including a circumferential groove 125a, which receives an 0-ring seal 125b. The to transfer passages 126 extend from the inlet chamber 124a through the base 120 and open through an upper surface of the first sealing annulus 125. The transfer passages 126 have a curved, substantially rectangular cross-section with rounded corners and are separated by webs 126a, which connect the base 120 to the stem 121.

The stem 121 includes a second sealing annulus 127 adjacent to, but spaced from, the splined end 122. The second sealing annulus 127 is also in the form of a flange, projects outwardly of the stem 121 and includes a circumferential groove 127a, which receives an 0-ring seal 127b. The diameter of the second sealing annulus 127 is smaller than that of the first sealing annulus 125, as are their respective 0-ring seals 125b, 127b.

The outer surface 128 of the stem 121 between the first and second annuli 125, 127 is recessed to describe part of a fluid passageway surrounding the axial bore 123. As a result, the transfer passages 126 extend from the inlet chamber 124a through the base 120 and open into this fluid passageway. The splined end 122 includes four radial projections, castellations or splines 122c spaced equally about its periphery and projecting outwardly therefrom. Each spline 122c is substantially arcuate and the circumferential extent of each is substantially the same as the circumferential extent of the spaces between them.

The outer part 103 is in the form of a banjo-type fitting 103, which includes an annular portion 130, a radial spigot 131 projecting from one side of the annular portion 130 and a push fit assembly 132 threadedly secured to the radial spigot 131. The push fit assembly 132 is similar to the push fit arrangement described in GB2521825A, the contents of which are incorporated herein by reference, and will therefore not be described in further detail herein.

The end cap 104 is substantially cylindrical with a side wall 140, an end wall 141 and four ledges (not shown) projecting inwardly from the side wall 140. The shape of the ledges (not shown) corresponds substantially to that of the splines 122c of the inner part 102. The end wall 141 includes a central hole 143 through its thickness and four arcuate holes 144 inboard of the side wall 140 and aligned with the ledges (not shown). It will be appreciated that these arcuate holes 144 are necessary for forming the ledges (not shown) in a conventional injection mould tool (not shown).

The annular portion 130 of the outer part 103 surrounds the inner part 102 and is retained lc) thereon by the end cap 104. To secure the end cap 104 to the inner part, it is first placed over the splined end 122 of the inner part 102 with the ledges 142 aligned with the spaces between the splines 122a until the splined end 122 of the inner part abuts the end wall 141. The end cap 104 is then rotated through 45 degrees to lock the ledges 142 with the splines 122a in a bayonet-type fashion.

The outer part 103 has a complementary internal shape to the inner part 102. The 0-ring seals 125b, 127b sealingly engage the internal surfaces of the outer part 103 to provide an annular outlet passage described between the outer surface 128 of the stem 121 and the annular portion 130. This annular outlet passage is fluidly connected to the inlet chamber 124a via the transfer passages 126 and feeds, in use into the radial spigot 131 and out of a pipe (not shown) connected to the push fit assembly 132.

This arrangement differs from the sealing arrangement of the device 1 of the prior art in that, inter alia, sealing is achieved using circumferential seals 125b, 127b. Contrary to the face seal arrangement of the device 1 of the prior art, the use of circumferential seals 125b, 127b precludes the need to apply a preload using a threaded end cap 4. Instead, a simple bayonet fitting is sufficient. As such, the force required to secure the end cap 104 is less and the radial spigot 131 is able to rotate more freely. This arrangement also reduces the risk of leakage.

The strap portions 106, 107 are connected to one another at a first of their ends by a screw threaded fastener 180 which threadedly engages a pair of pins 181, 182, each of which is captivated within a respective loop 160, 170 of the strap portions 106, 107. The pins 181, 182, are rotatably received in the loops 160, 170 and each loop 160, 170 includes a circumferential slot 161, 171 through which the fastener 180 extends to enable the strap portions 106, 107 to pivot relative to one another. The inner strap portion 107 includes a hole or receptacle 170a which receives the base 120 of the inner part 102.

The outer strap portion 106 has a series of slot pairs 162, one pair of which has an engaging end 163 adjacent its second end. The inner strap portion 107 includes three pairs of hooks 172 spaced along its length. When the strap portions 106, 107 are wrapped around a pipe (not shown), the first strap portion 106 overlaps the second strap portion 107 and the hooks 172 are received in the slots 162. The hooks 172 extend through the slots 162 in the first strap portion 106 and one of the hook pairs 172 engages the slot end 163. The strap portion 106, 107 defines an opening that is dependent upon which of the hooks 172 are in engagement with the slot ends 163.

The strap portions 106, 107 are preferably formed of sheet steel and the hooks 172 are provided by a deformed portion of the inner strap portion 107. The strap portions 106, 107 and connector 108 are similar to the strap arrangement described in W02016083786, the contents of which are incorporated herein by reference.

In use, the tool (not shown) is inserted through the hole 143 in the end cap 104 and through the hole 122a in the splined end 122 of the inner part 102 to engage the hexagonal socket 153 of the cutter 105. The cutter 105 is then rotated, as explained above in relation to the boring device 1 of Figure 1. In this example, however, the cutter 105 is only retracted sufficiently to clear the inlet chamber 124a, to avoid obstructing the flow out of the hole in the pipe through the transfer passages 126. The swarf is therefore retained within the threaded axial bore 123 permanently, around the undercuts 155 of the shank 151b, thereby preventing the swarf entering the pipe.

Referring now to Figures 11 and 12, there is shown a cutter 205 according to another embodiment of the invention. The cutter 205 according to this embodiment can also be used as a pre-cutter in the boring device 1 of Figure 1 or as a the sole cutter 205 for a boring device 100 of Figures 7 to 10. The cutter 205 according to this embodiment is similar to the cutter 105 described above, wherein like references depict like features which are incremented by 100.

The cutter 205 according to this embodiment differs from that of the embodiment described above in that the shank 251b has a cruciform-shaped radial cross-section. The shank 251b has four radial fins 251c extending perpendicular from one another, which run along the rotational axis of the shank 251b. The cutting head 251a is contiguous with two of the radial fins 251c. Each of the other two radial fins 251c terminate at the cutting head 251a, and include a lip 251d, which provides a shoulder mirroring part of the shoulder provided by the cutting head 251a, and a tapering end 251e that merges the radial fin 251c with the cutting head 251a.

The undercut 255 extends along only a portion of the shank 251b, adjacent the cutting head 251a, and includes a step 255a where it merges with the rest of the shank 251b. The steps 255a have a radial dimension substantially the same as, albeit slightly less than, the outer radial dimension of the cutting head 251a. The outer dimension of the shank 251b, specifically of each of the radial fins 251c, is larger than that of the cutting head 251a and steps 255a. The transition between the step 255a and the outer dimension of the radial fins 251c therefore acts as a stop, ensuring that penetration of the cutter 205 is limited to a predetermined depth.

In use and similar to the cutter 105 described above, each cutting tooth 254a, 254b, 254c, 254d cuts a continuous string of swarf (not shown) that wraps around the shank 251b. The undercuts 255 contain the swarf therein, and the provision of two additional radial fins 251c improves the ability of the shank 251b to engage and retain the swarf (not shown). The skilled person will appreciate that the cruciform cross-section also provides a stronger shank 251b, with greater torsional strength than the cutter 105 described above.

It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. The shank 151, 251 need not have a cruciform or flat radial cross-section. Whilst it may have a round or circular cross-section, an interrupted shoulder has been found to be particularly advantageous. As such, the shank 151, 251 preferably has radial fins 251, although these may be greater or less in number than four. In fact, whilst a cruciform cross-section has been found to provide an excellent balance between function and complexity, the shank may have any suitable cross-section, e.g. a concave polygon, that provides an interrupted shoulder.

It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.

Claims

CLAIMSA cutter for a boring device, the cutter comprising a cutting head, a threaded driving portion for engaging receipt within a threaded bore in a housing of the boring device, and a shank extending between the cutting head and the driving portion, wherein the shank comprises an undercut to enable swarf cut, in use, by the cutting head to wrap around the shank as the cutter rotates and advances within the housing.
2. The cutter of claim 1, wherein the cutting head comprises a pair of flanges extending io radially of a rotational axis of the cutter and a castellated cutting end along the flanges described by alternating cutting elements and voids.
3. The cutter of claim 2, wherein the rotational sweep of each cutting element on one of the flanges overlaps the rotational sweep of a corresponding one of the voids on the other flange.
The cutter of claim 3, wherein the cutting elements comprise three or more cutting elements and a corresponding three or more voids.
5. The cutter of claim 3 or claim 4, wherein the width of each cutting element is greater than the width of its corresponding void.
The cutter of claim 5, wherein the width of each cutting element is between 5% and 15% greater than the width of its corresponding void.
The cutter of any one of claims 2 to 6, wherein the axial depth of each void is between 50% and 90% of its width.
8. The cutter of any one of claims 2 to 7, wherein the axial depth of each void is between imm and 2mm.
The cutter of any one of claims 2 to 8, wherein the cutting head and at least part of the shank are substantially flat and the undercut extends from the cutting head toward the threaded driving portion.
10. The cutter of claim 9, wherein the flat portion of the shank comprises a shoulder between the undercut and the threaded driving portion for inhibiting the passage of swarf into the threaded driving portion.
11. The cutter of claims 9 or claim 10, wherein the flat portion of the shank tapers toward the cutting head.
12. The cutter of any one of claims 2 to 11, wherein the shank has a radial cross-section in the form of a concave polygon.
13. The cutter of any one of claims 9 to 12, wherein the shank has three or more radial fins each comprising a shoulder between the undercut and the threaded driving portion for inhibiting the passage of swarf into the threaded driving portion.
14. The cutter of any one of claims 13, wherein the shank has four radial fins describing a cruciform-shaped radial cross-section.
15. The cutter of claim 14, wherein the cutting head is substantially contiguous with a first pair of opposed radial fins of the shank and each of a second pair of opposed radial fins of the shank comprise a lip aligned with a base of the cutting head.
16. The cutter of any one of claims 2 to 15, wherein the cutting elements comprise cutting edges that are substantially perpendicular to the or a rotational axis of the cutter for making a blind bore.
17. A pipe boring device comprising a cutter according to any preceding claim, a housing and a strap for mounting the boring device to a pipe, the housing having a tubular body with a base for engaging the pipe and a threaded bore extending from the base into the tubular body with the cutter received therein.
18. The boring device of claim 17, wherein the housing comprises a fluid passageway at least partially surrounding the bore and an outlet for connecting the fluid passageway with an off-take pipe, wherein the base comprises one or more transfer passages external of the bore which provide, in use, fluid communication between the fluid passageway and a hole formed in the pipe by the cutter.
19. The boring device of claim 17, wherein the housing comprises a transverse hole extending from the threaded bore to a fitting for connection with an off-take pipe.
20. The boring device according to any one of claims 17 to 19 comprising a further cutter which includes a threaded driving portion for engaging receipt within the threaded bore in the housing and a tubular cutting member having an annular or part-annular or segmented annular cutting edge.
21 A kit of parts for assembly into a pipe boring device according to any one of claims 17 to 20, the kit comprising a first cutter according to any one of claims 1 to 16, a housing and a second cutter having a threaded driving portion and a tubular cutting member having an annular or part-annular or segmented annular cutting edge, the housing comprising a tubular body with a base for engaging a pipe and a threaded bore extending from the base into the tubular body, wherein the housing is configured to receive the first cutter in the threaded bore for cutting a blind bore in a pipe and to receive the second cutter in the threaded bore for cutting through the base of the blind bore to penetrate the wall of the pipe.
22. A method of cutting a hole in a pipe, the method comprising: driving a cutter within a housing mounted to the pipe such that a cutting head rotates and advances into a wall of the pipe to form a swarf that wraps around an undercut of a shank of the cutter connected to the cutting head as the cutter advances; and retracting the cutter with at least part of the swarf wrapped around the shank.
23. The method of claim 22 comprising: retracting the cutter before the cutting head penetrates through the wall of the pipe, thereby to provide a blind bore in the wall of the pipe; replacing the cutter with a second cutter having a tubular cutting member; driving the second cutter within the housing such that the tubular cutting member cuts an annulus from a base of the blind bore through the wall of the pipe; and retracting the second cutter to open fluid communication between the pipe and an off-take pipe.
24. A computer program element defining a three-dimensional design of the cutter of any one of claims 1 to 16.
25. A computer program element according to claim 24 comprising computer readable program code means for causing an additive or subtractive manufacturing system to execute a procedure to manufacture the cutter.