GB2176140A - A machine for cutting and chamfering pipes - Google Patents

Abstract

The machine cuts a pipe R and subsequently chamfers the cut end, using a combined cutting-off and chamfering tool 3 or a cutting-off tool and a chamfering tool, having at least one inner and one outer chamfering edge. Pipe-holding parts 49 clamp the cut pipe portion during processing. A driven drum 37 surrounds the pipe-holding parts 49 and is borne by a bearing sleeve 21. One or more tool holders 42 are adjustable radially relative to the pipe axis The drum 37 has axially movable with it a control ring 40 for radially adjusting the tool holders 42. The drum 27 is axially adjustable by a stationary, linear drive unit 31. When the control ring 40 rotates relative to the drum 37 the tool holder or holders are radially adjusted. The parts 49 are piston 43 operated. <IMAGE>

Description

SPECIFICATION A machine for cutting and chamfering pipes The invention relates to machines for cutting pipes and chamfering the cut edges of the pipes.

German Auslegeschrift 11 88 413 discloses a device for radially adjusting a cutting knife disposed in a rotating knife head in peeling machinesorothertools in similar machines. The peeling machines or other radially adjusted via an axially adjustable, movable adjusting sleeve having oblique sliding surfaces,the sleeve being rotatably but non-movably mounted on an axially adjustable regulating sleeve. The regulating sleeve is movably and non-rotatably mounted, via a groove and tongue, in a tubular part secured to the machine. A similar machine comprising an axially adjustable regulating sleeve is disclosed by German oeoffenlegungsschrift3l 48727.

US Patent 3563 119 discloses a machine forcutting off pipes and subsequently chamfering the cut-off pipe ends, using a combined cutting-off and chamfering tool, ora cutting-offtool and a chamering tool, having at least one inner and one outer chamfering edge, comprising at least one pipe-holding part clamping the cut pipe portions during processing and a driven dum surrounding the pipe-holding part and borne by a bearing sleeve and one or more tool holders adjustable radially relative to the pipe axis, the drum having means for radially adjusting the tool holder or holders.

In the last-mentioned machine, cutting is brought about by radially moving the combined cutting-off and chamfering tool relative to the pipe, after which, at the end of the cutting-off process, the tool is radially moved back outwards and the two pipe portions are moved apart so thatthechamfering partofthe tool can enterthroughthegap between the two facing ends ofthe cut pipe portions. The pipe portions then have to be longitudinally adjusted relative to the tool to an extent depending on the chamfer, i.e. the end-faces are chamfered by accurate longitudinal adjustment of the pipes against the chamfering tool, which is axially and radially immovable but rotates around the pipe axis.

The aim of the present invention isto improve the known machine so asto obtain moreaccuratecham- fering after a short machining time, particularly in the case of long and/or heavy pipes. Another aim isto simplify some of the means used.

In accordance with the invention the drum is axially adjustable byastationary, linear drive unitand on its front portion bears a control ring which is axially immovable relative to it, and when the control ring rotates relative to the drum the tool holder or holders are radially adjusted.

Optional and prefered features of the invention are defined in the sub-claims 2 et seq.

The invention has the advantagethatthe pipe portions, some of which are long and/or heavy, do not move longitudinally so as to determine the position and size of the chamfer. Chamfering is always brought about by the rotating tool, axially adjustable relative to the pipe axis, when the pipe portions are at rest.

The accompanying drawings show the main parts of an embodiment of the machine according to the invention and how it operates when using two variously-combined tools.

In the drawings: Figure 1 is a partial longitudinal section through the machine; Figure2 shows a first combined tool; Figures 3a - fshow operation with the firsttool; Figure 4shows a second combined tool; and Figure 5a - c show the operation of the second tool.

The embodiment illustrated in Figure 1 comprises a casing 20 in which a bearing sleeve 21 is secured, e.g.

by a row of bolts 21 a disposed in a circle. The row of bolts can be interrupted by one or more setting screws disposed axially parallel to the bolts 21 a. The bearing sleeve 21 extends approximately along the entire length a of the machine, is generallytubular, and has a cylindrical portion 22 and, at its rear end, an annularflange 23 by means of which the bearing sleeve 21 is secured to the machine casing 20.

A feather 24 is held ontheperipheryofthecylin- drical portion 22 of the sleeve 21 and engages a groove 25 in the cylindrical portion 26 of a movable adjusting sleeve 27, which bears a projection of a-nnu- larflange 28. The adjusting sleeve 27 is thus movable on the bearing sleeve 21 in the direction of the double arrow 29, but is prevented from rotation by the feather (tongue) and groove.

The projection orflange28,which extends outwards, engages the push and pull rod of an adjusting means (in the present case the piston rod 30 of a piston-and-cylinder unit31) which is secured to the casing 20 and is adapted to move the adjusting sleeve 27. Any other linear drive can be used instead ofthe unit31.

The piston rod 30 bears two longitudinallymovable, lockable abutment rings 30a, 30b, and adjustments can be made to the distance between the rings and the end face 31a ofthe cylinder 31 b andthewall 20a ofthe casing 20. Preferably a number of pistonand-cylinder units 31 are disposed in a circle around the axis of the pipe Rand their piston rods 30 with rings uniformly engage the adjusting sleeve 27.

Bearings 32,33 are disposed at respective ends of the cylindrical portion 26 of the adjusting sleeve 27 and are held by corresponding spacer means 34 and by a shoulder 35 and a retaining ring 36. The distance between the two bearings 32,33 is large and at least equal to half the length of the bearing sleeve 21. As a result, a cylindrical drum 37 mounted on the bearings 32,33 is accurately guided longitudinally and also in the best position for receiving radial and axial forces acting on it.

The drum 37 has peripheral teeth 38 which engage a corresponding spur gear (not shown) in order to rotate the drum 37 on the movable adjusting sleeve 27 and round the pipe R.

The front box-like portion 39 of the drum 37 bears a control ring 40 which has external teeth 41 enabling the control ring to rotate relative to drum 37. As a result of this relative rotation, a tool-bearing means 42 (represented symbolically by a bent part in Figure 1) is radially moved, so that a tool-holderW and tool 3 secured in the said means 42 can carryoutthe cut ting-off process in the direction of arrow 6. The means 42 is preferably a slidermoved radiallybythecylin- drical adjusting ring 40 in the radial groove of a disc on the drum 37, a number of said means 42 being radially guided on the disc.

A clamping piston 43 is axially movable in the bear ing sleeve 21 connected to the machine casing. Cylin der chambers 44,45 in front of and behind the piston end faces 43a, 43b can be supplied with pressure medium ordepressurized via lines 46 and 47, so that clamping jaws 48 clamp the pipe R in chuck jaws 49 or release ittherefrom.

The chuckjaws49, concentrically surrounding the pipe, are connected in axially movable mannertothe clamping jaws48 by screws 51 having heads extend ing into an oblong hole 50 in the chuckjaw 49, and are prevented from rotation by a feather53 engaging in groove 52. The rear end of the clamping and chuck jaws can be connected to a ring so thatthe chuck jaws can move as required for clamping and releasing but can also be axially adjusted with the ring. The ring can be axially moved by any suitable adjusting means.

Acasing-partwall 55 bears a preferablyaxiallyad- justable abutment againstwhich the ring ofthe chuck jaws 49 abuts when moving to the left in Figure 1 and thus defines the rearmost position (positiontothe furthest left in Figure 1) ofthe jaws 49 and ofthe illustrated pipe portion behind the cutting-off tool 3.

AtZ,i.e. atthe level ofthe pipe portion Kinfrontof the cutting-offplace, a similar device for clamping and axially moving the cut pipe portion can be pro vided, if the machine isto be used for cutting and chamfering the two facing ends of the two cut pipe portions. Any other device can be used for axially adjusting and limiting the backward and forward mo tion ofthe pipe portions after cutting.

Figures2 and3a-3fshowa tool 3 suitableforusein the tool#-bearing means 42. The tool has a shank 60 or other suitable part for guiding in the radial groove of the disc connected to drum 37. The tool also has a cutting-offpart6#1 which extends radiallytowards pipe Rand is coaxial with shank orparalieítothe groove in the disc. A double trapezoidal chamfering part 62 is disposed between shank 60 and cutting-off part 61 and used for chamfering the inner and outer edges ofthe ends of the two cut pipe portions. The trapezoidal part 62 and the longitudinal axis L ofthe tool can include an edge angle awhich is equal to or different from the edge angle P included between part 63 and longitudinal axis L.

As shown in Figure3a,thechamfering part 61 cuts the pipe into portions Sand T and is them moved a short distance in the direction of arrow Q in orderto form the outer chamgers 64,65 on portions Sand T.

Next, the two pipe portions Sand Tare moved apart until the ring (not shown in Figure 1) connected to #jaws 49 and axially moving them comes againstthe adjustable abutment at wall 55 or until the corres ponding deviceorpipe portionThascomeintooper- ation.

Of course, any other means can be used for moving portions Sand T apart by a given amountforobtaining a gap a through which the outermost edges 66 of tool 3 can be inserted. The chamfering parts 62 oftool 3 then travels through gap a, so that its edges come level with the inner wall of pipe portions S,T(Figure 3d),after which the two pipe portions and T are chamfered by moving the tool in the direction of arrows P1 and P2. The chamfering accu racy therefore depends only on the adjusting motion of tool 3,since the pipe portions are held motionless during cham fering.

Figure 4 shows a tool 130 having a shank 60 and a short chamfering part 70 which can also have a shape differentfrom that shown. It has two portions 71 and 71; portion 72 has two working edges 73,74 disposed in pairs at the same height, edges73 likewise being used for cutting whereas edges 74 are for chamfering the inner wall of pipe portions U, V, the same being done by edges 75 of portion 71 with regard to the outer chamfer or portions U and V. Tool 130 is radially adjusted, makes a cut and forms a gap b through which tool portion 72 is inserted between pipe portions U and Vsothatthe plane ofthe cut 76 between the two tool portions 71,72 is level or app roxim ately level with the central plane 77 of the pipe wall. Tool 130 is then adjusted in the direction of arrowsx andy until one of the rings 30a,30b on the piston rod 30 axially movin#g the tool abutsthewali 31a or20a, when tool 3 is adjusted during motion as per Figures 3e and f. As before, pipe portions U and V are held motionless and only tool 130 is moved (axially and very accurately) by rings 30a and 30b, thus obtaining a very accurate chamfer.

If only one, e.g. the front edge of each pipe portion, has to be chamfered, the tool can be correspondingly shaped and the device for gripping and longitudinally moving the cut pipe portion K atZ in Figure 1 can be eliminated or switched off.

Claims (8)

1. A machine for cutting a pipe and chamfering the cut end, using a combined cutting-off tool and a chamfering tool, the tool(s) having at least one inner and one outer chamfering edge, the machine comprising pipe-holding means for clamping the pipe during processing, a driven drum surrounding the pipe-holdingmeans and borne by a bearing sleeve, and one or more tool holders adjustable radially relative to the pipe axis, the drum having means for radially adjusting the tool holder(s),the drum being axially adjustable by a stationary, linear drive unit and bearing a control ring which is axially immovable relative to it, rotation of the control ring relative to the drum causing radial adjustment of the tool holder(s).

2. A machine as claimed in claim 1, in which the drum is rotatably and axially immovable disposed on a non-rotatable adjusting sleevewhichengagesthe piston rod of a stationary piston-and-cylinder unit for axially adjusting the adjusting sleeve.

3. A machine as claimed in claim 2, in which the adjusting sleeve is axially movable on the bearing sleeve and has a radially outwardly projecting mem ber engaging the piston ofthecylinder-piston unit, which is coaxial with the drum, the adjusting sleeve, and the control ring.

4. A machine as claimed in claim 2 or 3, in which the-non-rotatable, axially movable adjusting sleeve extends along more than halfthe length of the bearing sleeve and the drum is mounted on the adjusting sleeve on both sides of a cylindrical portion thereof.

5. A machine as claimed in any of claims 2 to 4, in which the piston-and-cylinder unit has means for variable axial adjustment ofthe position ofthe adjusting sleeve, the drum, and the control ring.

6. A machine as claimed in any preceding claim, in which the pipe-holding means is axially adjustable against an abutment on the machine casing.

7. A machine as claimed in any preceding claim, associated with a device which clamps a cut pipe portion and is movable axially against an abutment.

8. A machine for cutting a pipe and chamfering the cut end, substantially as described with reference to, and as shown in, the accompanying drawings.