GB2365811A

GB2365811A - Pipe preparing tool

Info

Publication number: GB2365811A
Application number: GB0017984A
Authority: GB
Inventors: David Harget; Michael Kenneth Greasley
Original assignee: Uponor Ltd UK
Current assignee: Uponor Ltd UK
Priority date: 2000-07-24
Filing date: 2000-07-24
Publication date: 2002-02-27
Anticipated expiration: 2020-07-24
Also published as: GB2365811B; GB0017984D0

Abstract

A pipe preparing tool (1) comprises a cutter assembly (3) mounted in the wall of a cup-body (2) for free radial movement relative to the cup-body. A cutter (6) is mounted in the assembly for engagement, in use, with a pipe surface (74) of a pipe (70) inserted in the cup (78) of the cup-body. A tangential plane of the surface in contact with the cutter is substantially perpendicular to the radial direction. The tool (1) is adapted for movement over said surface circumferentially on rotation of the tool about the pipe. The cutter (6) has an inclined knife edge (13) to cut into the surface.

Description

<Desc/Clms Page number 1> PIPE PREPARING TOOL VI

This invention relates to pi-pe preparing tools, and more Darticularly to a novel pipe preparing tool suitable z for cutting, scoring or penetrating a surface of a 4 relatively small'- d.ameter plastics #)iine. Composite plastics pipes comprising an inner core and an outer Drotective layer are known. The outer protective layer may, for example, provide environmental protection, or protection against mechanical damage when the pipe is laid in a trench. In joining sections of such a pipe, iL- has been proposed to remove the outer p-rotective layer in order to permit the installation of a pipe coupler, such as, for example, an elect-rofusion pipe coupler. Examples of such pi-pes with outer protective layers are described in WO-A-930021-2, WO-A-9215818, EP-A- 0474583 and in WO-A-9622485, the encire disclosures of which are incorporated here'Ln by reference for all purposes. in practice it has proved to be extremely difficult to remove the outer protective layer cleanly from the pipe inner core witnout damaging the inner core when using conventional tools such as knives, scrapers etc. In G2-A-1487033 there is described a tube cutting and chamfering tool comprising an adjustable C-shaped frame, a pair of spaced cutting wheels arranged in a common plane, supporting rollers for the tube, and a chamfering cutter adjustably located between the two cutting wheels. This tool is quite complex in design and is not readily adapted to remove the outer protective layer of a composite pipe.

G2-A-1458366 describes a tool for cutting a cable sheath wh--'Ich Comprises a loop-like frame, including at least two hingedly connected parts, means for releasably holding the frame parts in closed loop form, a handle connected to the frame, and a cutter assembly mounted for adjustment both inwardly and outwardly of the loop and angularly about the axis of its inward and outward movement. The cable sheath is supported by rollers mounted on the frame and, in some embodiments, also on the cutter assembly. This tool is complex both in design and ooera##--ion. US-A-3943626 describes a pipe cutter adapted to be mounted on a chain pipe wrench. The pipe cutter com#Drises a cuc:ter 1:)i#. which projects adjustable beyond a rigid body me=,er mounted on guide wheels. GB-A-2207377 describes a plas t 4 C pipe cut-er which com#Drises a set of pipe grips and a cutting tool ring. Thl_- cutting tool ring comprises two half round steel bands which are hinged and have a fastening clamp. The cutting tool is housed in a rigid slotted boss. G2-A-21450'47 describes a tool for removing a surplus bead of material from a pipe. The too 1 comprises a blade carried in a rigid blade holder formed in two half body portions carried on releasable clamping means comprising a pair of semi-circular steel straps. In GB-A-2296886 there is described and claimed a pipe preparing tool which comprises: # frame having an opening adapted to receive a pipe or a portion thereof, # first tapered roller means mounted transversely on the frame;

a second tapered roller means mounted transversely on che frame and spaced apart from the first tapered roller means; -the arrangement being such that the first and second tapered roller means have opposed directions of taper; a cutting, scoring or penetrating means mounted on t.h-e frame and s-oaced anart from the first and second roller means; and clamping means adapted to apply a clamping force to the pipe such that the first and second tapered roller means and the cutting, scoring or penetrating means are broug-lit into contact with the pipe and the cutting, scor-ilng or penetrating means penetrates a surface layer of the pipe,- the arrangement being such that the pipe and the tool can be rotated relatively to one another about the axis -he pipe whereby the cutting, scoring or penetrating means -croduces a helical groove in at least a surface layer of the pipe.

This tool works well in practice, and can be used to strip off the outer layer of a composite pipe, but again some further simplification Of the design would be desirable. In particular, it would be desirable to provide a cheaper tool and one wherein the number of moving parts, such as rollers, can be reduced.

There is sometimes the need to provide differently- sized tools to cope with pi-pes of different diameters. For example, the tool of G2-A-2296880' is limited in that it can only be used for pipes of small enough diameter to fit between the rollers 5-8 and the sliding arm 12 at its maximum setting. Some prior art tools cannot cater for pipes which are out of round, for example slightly oval

as a result of storage in a co-41. 777 pU'-7 #-- a copending applicat-'On to be #_;_ished under the number GB-A-23q5875 --here is provided a pipe preparing tool com-or-ising: # body having -1':JL--sL and second contact points; and # cutter assemh1v mounted on --he body between said contact ncin-k-s and freely slidable along an axis which is, -J n use, subs- -1 ant ial ly nerQendicular to c he -Longitudinal axis cf: the p-pe, and compriisina a cut -ter adapted, in use, z--o engage a su--race cf the pipe when said contact points bear against- the pipe. The cutter may he provided with a cutting blade which is angled, in use, with respect to the surface of the pipe, and it may be provided wit--!.-). a heel located adjacent t'ne cutting blade to prevent more than a predetermined depth of cut. This is a verv effective arrangemen-- in which, when the tool is used to prepare a pipe having a surface skin on an inner core, the blade seems to find the interface between the skin and core and cut substantially only the skin, so that it can be peeled with relative ease. US-A-5600862 descrIbes a ;Dine scraper for removing a un-i-`7orm amount of material from the end of a pipe in which a cup rece.-ves the pi-pe and has a blade fixed in the wall of the cup protruding into the bore of the cup. Biasing means press the pipe against-- the blade so that always the same amount of material is removed from the pipe by the blade as the pine is rotated inside the cup. Such an arrangement is convenient but it suffers from being restricted i n the diameter o t pipes it can

accommodate. Also it is somewhat complicated in its provision of biasing means. It is an object of the present invention to provide a pipe preparing tool which comblines the advantages of the tools described in GB-A-2345875 and US-A-5600862. It is a further object to provide a pi-pe preparing tool of relatively simple construction capable of cutting or scoring the outer surface or a pipe and which is easy to In appropriate embodiments, the outer procective use. layer of a skinned pipe can be penetrated so that it can readily be peeled cleanly away from the underlying pi-pe without any substantial damage to the underlying pipe. In a first aspect of the present invention, there is provided a pipe preparing tool comprising a cup-body; and a cutter assembly mounted in the wall of the cup-body and beinng freely slidable along an axis which is, in use, substantially perpendicular to the longitudinal axis of a pipe inserted in the cup of the cup-body, the cur-ter assembly comprising a cutter adapted, in use, to engage a surface of the pipe when the pipe is inserted in said cup. The cutter is preferably provided with a cutting lolade which is angled, in use, with respect to the surface of the pipe. Preferably, it is provided with a heel located adjacent the cutting blade to prevent more than a ioredetermined depth of cut. Preferably, the cutter is removable from and replaceable in the cutter assembly. In a second aspect of the invention, there is

crovided a pipe -rei#)ar 4 ng tool comnr#s`nq t, - - I. a cutter assembly mounted _Jn the wall of a cup-body for free movement relative to the cup-body in a first direction, a cutter mounted -:n --I-e assemLly for e-n-gagement, in use, with a pipe surface of a pipe inserted in t1le cup of the c-up-body, a tange-Lia'; plane of which surface Jn contact with the cutter is substantially perpendicular said first direction, the too,- being adapted for movement over said surface 1-n a second direction substantially perpendicular said first direct'Lon, the cutter having a knife edge to cut int_-o said sur-Face, said edae beinCr 4 L nc-ined wi-1respect to said plane. Prefera-'-1-v, S::: knife edge substantial1v perpendicular said second d1rect-ion. Preferabiv, sa`#.d knife edge has a distal -region remote -from a connection of the knife edge to the cutter, whicin distal region is adapted, in use, to coincide with an interface between a surface layer and an inner layer of the pipe. ideally, said distal region is inclined with- respect to said knife edcie so as t 0 lie substantially parallel said plane. Pre Ferahly, sa-,# L_ kn' '7e edge s incl 4 ned forwardly in the direction of cut. Preferably, the cutter assembly is capable 0 J_ withdrawal so that it does not izitrude into the cup of the cup-body. Preferably, sizing sleeves are provided to reduce the bore of the cup so that different diameter pipes can be accommodated in the tool. The sizing sleeves have a bore in their side to permit through passage of the cutter

assembly. Preferably, means prevent rotation of the cutter assemblv in the cup-body so that orientation o4:# the cutter is so as to effect a circumferential cut in the pipe surface on rotation thereof in the cup-body, Means mav be -provided to permit angular adjustment of the cutter assemblv in the cup-body so that orientation of the cutter may be so as to effect a iongizudiinal cut in the pipe surface on insertion of the r-i-ce into the cupbody. Said rotation prevention means preferably comprises a pin _i- the wall of the cup-body engaging a slot in the cutter assembly. Preferablv, said angular adjustment means comprises said cutter assembly being rotatably d-is-cosed about its own axis in said cup body and a circumferential extension of said slot around said cutter assembly. in a third aspect of the invention, there is provided a method for cutting the outer surface of a pi-pe in which there is used a pipe preparing tool substantially as described above. Preferred embodiments of the #)resent invention will now be more particularly described, by way of example only, with reference co the accompanying drawings in which: Figure 1 a and b are a cross and longitudinal section respec##ively, along the lines a-a and b-h in Figures 1 b and a respectively, of a pipe preparing tool embodying the present invention; Figures 2 a and b are a front view and side view

respectively of" the cutter of the tool of Figure 1; and Figures 3 a, b and c are side, perspective and plan views of the cutter body. Referring to Figures 1 a and b, a pipe preparing tool 1 comprises a cup-body 2 of cast metal or plastics material. A cutter assembly 3 is mounted in a bore 50 4-1-7-1 the bodv, such that it --1s radially moveable relat-Live to the body 2. The cutter assembly comprises a dome-shaped head 4 which, in use, serves as a handle is easil.#; qrip;Ded by the user of the pipe preparing tool. The head 4 is rigidly fixed to a s',.#bstan----'ally cylindrical sleeve 5. At the end of the sleeve 5 remote from --he head 4 is the cutter 6 itself. Although ';_-. use, the cu#------er 6 #.s firm-Ly fixed in Qosi--ion, the cutter mav be removable and replaceable is Rotational movemenl-- OL the cutter assembly - substantially prevented by a grub-screw 52 having a pin 54 in its end and which engages a slot 56 in the sleeve 5. In F--gur--s 2 a and b c-uz#ter 0' Inas a scruare section shaft 7 which passes though the centre of sleeve 5 to head 4, wh-'e-re it is held in place -by a screw 8, which is received in a threaded hole 81 in shaft 7. The square section shaft 7 is received in a corresponding square bore 64 of the sleeve 5. Thus the cutter is rotationally fixed with respect to the sleeve 5. on loosening the screw 8, the cutter 6 and its shaft 7 can be easily removed from the sleeve 5 and the old cutter 6 can be substituted by a new cutter; the new

cutter and shaft 7 then simply being replaced into the TD-Lpe preparing tool it being retained in the cup -body 2 by #_'ae (grub screw 52. A pipe 70 has a core 72 and a skin 74 adhered to a T t greater or lesser extent to the core 72. is usually desired to remove the outer skin 74 at -the end of the P-41r)e 70 in order to join two such pipes together using an electrofusion coupler. A sizing sleeve 76 is first _'nserted in the cup 78 of t':Ie cup-body 2. An a3Derture 80 of the sizing sleeve is arranged to coincide with the bore 50 of the cup-body 2. This may be facIllitated by a slot 82 in the cup 78 adapted to receive a dog 84 of the sizing sleeve 76. The sizing sleeve is arranged to be a close sliding fit on the oipe 70. Different sized sleeves 716 may be provided for different sized pipes, or indeed may be omitted altogether for the largest diameter pipes co be peeled with the assistance of the tool 1. To the same degree, the sleeve 76 may have bottoms 86 of different deQths, or 4 such bottoms may be omitted altogether, = dependence on "the distance from t-1-ie end of the piiDe 70 it is desired to peel the skin 74. Referring, in particular, to Figures 2a and b, the cutter 6 is freely moveable in a first direction or axis 20 by virtue of the head 4 and sleeve 5 being slidable in the bore 50 of the cup-body 2. The cutter 6 has a cutting blade 13. The blade 13 is 4Z formed by grinding a circular groove 22 in the cylindrical head 6' of the cutter, followed by an angled saw cut 24. Finally the so for-Ined blade 13, having a cutting edge 13' , is deflected downwardly.

The leading poJn, at which the cutting blade 13 contacts the outer layer of the pipe is point X. Where point X contact-s a p1pe surface, a ta-nqer-tial plane of the pi-pe is defined. The cutting edge 13' is arranged substantially perpendicular to the direction of cut and incli-ned downwardly w'Lthi -respect to the tangential -plane. In pipes 70 to which the present invention relates, the thickness of the skin 74 is substantially constant, regardless of diameter of the 3D'L.#De and the length and inclination of the blade 13 is arranged so that its ti,p X is just below the level of the interface between the sk-in and core. A flat por#:ion or heel 14 is provided beside the cutti-q blade 13, as shown in Figure 2a, which serves to i--reven7: "submarinIng" o-f t-e blade into -the outer surface of the pipe during the cutting operation. The dimensions and angles for -he L cutter 6 may be as follows: it may have a cutter diameter D of about Smm, so that the length of the cutting blade 13 is about 4mm, the anale of in-clination a of the slot 24 with respect to the axLs 20 is abou-. 70'- the base of the cutting blade s ground to an angle P of about 87' with respect to the axis, ideally be-Fore the slot 24 is cut; and the angle of inclination ( of the blade 12 is about 99') to the axis 20 . Referring also back to Figure la and b, the blade 13 is positioned so that it is normally substantially longitudinal of a pipe 70 in the cup 76. However, the slot 56 in the surface of the sleeve 5 is U-shaped having two legs 56a,b substantially at right angles to one another around the axis 20, and joined by a base 56c.

Thus, by lifting the head 4 so that the pin 54 contacts the base of the slot 56a, the cutter assembly 3 can be rotated wi-#h the #,cin sliding in -the base 56c. When the slot 56b is reac-'ried, the cutter assembly can again be lowered in the cup-body bore 50, but-, this time the blade edge 13' is circumflerentially disposed, facing the open end of the cup 78. The foillowIng description exclains how the p-;'_pe preparing tool of the -Qresent invention can be used to S.I < 4 cut throug1h the ou-Ler protective _M of a pipe so that the skin may be readily peeled away, without causing any substantial damage to the underlying pipe. It wi..ll be appreciated, however, that the pipe preparing tool of the present invention is also suitable for cutting or scoring the outer surface of a plastics pipe which does not have such an outer protective skin. To use the pipe preparing tool, cutter assembly is pulled out of the bore 50 as far as possible and rotated so that the blade 13 of the cutter 6 is arranged to face the opening of the cup 78. An appropriate sizing sleeve 76 for the pi-pe to be peeled (if one is necessary) is inserted in the cu;D 78. The cutter assembly is then rotated until t_-he blade 13' faces the mouth of the cun 73, and then dropped until a foot 5b of the sleeve 5 contacts the base 50b of the bore 50. A pipe 70 is then inserted in the cup 78, or sizing sleeve 76, as the case may be, until the cutter 6 is contacted. The assembly 3 is then raised until a forward extension 14' of the heel 14 just clears and rests on the leading edge of the pipe. The head 4 is then pressed downwards gently, its movement downwards being prevented by the front edge of the pipe. The pipe is then pushed into the cup 7B until it hits the

bottom. However, in the process, the blade 13 cuts through the skin o-"" the pi#De, slince the blade depends below the heel 14' - The cut will be longitudinal of the pipe, as deep as the pipe is inserted into the tool 1; that is to say, depending on the thickness o-E the base 86 of the sizing sleeve 76. When pushed home, the assembly 3 is lifted until the nin 54 Contacts the base of the slot 56b, whereupon the head 4 and sleeve 5 are rotated through 90 degrees with t:'ne nin sliding in -- i rcumfe rent: -4 a! slot 56c. When the side of slot 56a 'is contacted, the head 4 is again pressed downwardly gently -intil the blade contacts the surface of the pipe. As the i s rot-#--ed (relativel-v) about its own axis in -the -73, the blade ---3 will penetrate the skin 74 until its -4 p enters the interface between ##'-ne skin and core. T- arly event, the heel 11 contacts the top surface o -ff '-#--e -cice and prevents submarining of the blade if the skin should be thinner than the rake of the blade 13 is adapted to accommodate. The design of the cutting blade 13 is such that, after the initial cut is made into the skin, downward pressure on the head 4 is no longer required as the tool travels around the periphery ol` the pipe, cutting the skin away from the underlying pipe. The cutting blade 13, or at leas-#- its point X, "settles" at the inte=ace between the skin and the underlying pipe and resists any forces tending to eject the cutting blade from the cut it is making. Movement of the cutter assembly 3, which is freely slidable in the bore 50, whilst the cutting action takes place, permits the blade to stay in this settled position. Indeed the distal end of the blade 13 could be inclined again so that it is substantially parallel the

longitudinal axis of the pipe 70. Moreover, the freely s1liding movement of the cutter assembl-v in cup-body means that, not only can the tool readily cope with pipes of different diameters, (so long as sizing sleeves ar e employed) but also that it can cope with pipes which are out of round, for example slightly oval (as is caused when pipes are stored on a coil.) . Once the cutting blade 13 has settled at- the interface between the skin and the underlying pipe, variations in diameter can be easily cooed with, the cutter assembly automatically moving up or down, to compensate. The skin is lifted or Irlared" where it contacts the angled blade so thac it can easily be gripped and peeled away from the underlying pipe. The Qresent invention therefore provides a pipe preparing tool which is both simple and effective to use. Furthermore, the tool is safer than many prior art devices as the blade is protected within the cup-body of the tool.

Claims

1 A pipe preparing tool comD , , rising a cup-body; and a cu#_-ter asser-bly mounted in the wall of the cupbody and being freely slidable along an axis which is, in use, substantiallv oe_-nendicu#ar to the longitCudinal axis of a pipe inserted J_T _-1 the cup of the cup-body, the cutter assemblv comorising a cutter ada3Dted, in use, to engage a surface of z#he piece when -the Pipe is inserted in said cu p . 2. A pipe preparing Loci as claimed in claim 1, in wni ch -the cu'Eter I s iDrovided with a cutting blade which is analed, in use, with respect to T#he surface of the oi#:)e. 3. A pipe preparing tool as claimed in claim 2, in which t_-he cu-1-ter is #Drovided with a heel located adjacent the cutting blade to prevent more than a predetermined depth of cut. 4. A pipe preparing tool as claimed in claim 1, 2 or 3, n w,4ch h_L the cutter is remo7,rahle from L and replaceable in the cutter assembly. 5. A pipe preparing tool comprising a cutter assembly mounted in the wall of a cup-body for free movement relative to the cup-body in a first direction, a cutter mounted in the assembly for engagement, in use, with a pipe surface of a pipe inserted in the cup of the cupbody, a tangential plane of which surface in contact with the cutter is substantially perpendicular said first direction, the tool being adapted for movement over said surface in a second direction substantially perpendicular

said -first direction, the cutter having a knife edge to cut into said surfac_-, said edge being inclined with respect to said Qlane. 6. A -p_Jpe preparing too! as claimed in claim 5, in which said knife edge is substantially perpendicular said second direction. 7. PL iDipe pre#)arina tool as claimed in claim 5, in which said knife edge has a distal region remote from a connect"Lon of the 'knife edge to the cutter, which distal region is adapted, in use, to coincide with an interface between a surface skin and an inner core of the pipe. B. A pipe preparing tool as claimed in claim 7, in which said distal region is inclined with respect to said knife edge so as to lie substantially parallel said pl, ane . 9. A pipe preparing cool as claimed in claim 7 or 8, in which said knife edge is inclined forwardly in the direction of cut. 10. A pipe preparing too! as claimed in any preceding claim, in which the cutter assembly is capable of withdrawal so that it does not intrude into the cup of the cup-body. 11. A pipe preparing tool as claimed in any preceding claim, in which sizing sleeves are provided to reduce the bore of the cup so that different diameter pipes can be accommodated in the tool. 12. A pipe preparing tool as claimed in claim 11, in which said sizing sleeves have a bore in their side to permit through passage of the cutter assembly.

13, A pipe preparing tool as claimed in any preceding claim, in which means Prevent rotat-Lon of the cutter assembly in the cup-body so that, orientation of the cutter is so as to ef]Eect a circumferential cut in the pipe surface on --rotation thereof in the cup-bod-v. 14. A pipe preparing tool as claimed in claim 13, in which said rotation #Drevention means comiDrises a pin in the wall of the cup-body engaginq a slot in .--he cutter assem.bly. 15. A pipe preparing tool as claimed in any preced-nu claim, in which means permit angulal- adjustment of the cutt#(.:#r assembly in the cup-body so #:hat orientation ofL the cutter may be so as to effect a longitudinal cut in 7he pipe sur'Lace on insertion of the pipe into the cupbody - 16. A pipe preeparing tool as claimed in claims 14 and 15, in which said angular adjustment means comprises said cutter assembly being rotatably disposed a-bout its own axis in said cup body and a circumferential extension of said slot around said cutter assembly. 17. A method for cutting ---he outer surface of a pipe in which there 'is used a pipe preparing tool as claimed in any preceding claim. 18. A method for cutting the outer surface of a pipe substantially as described herein with reference to and by any appropriate combination of the as I accompanying drawings. !9. A pipe preparing tool substantially as described herein with reference to and as illustrated by any appropriate combination of the accompanying drawings.