GB2359773A

GB2359773A - Machining round bodies.

Info

Publication number: GB2359773A
Application number: GB0031378A
Authority: GB
Inventors: Fridtjof Lovaas
Original assignee: Framo Developments AS
Current assignee: Framo Developments AS
Priority date: 1999-12-23
Filing date: 2000-12-22
Publication date: 2001-09-05
Anticipated expiration: 2020-12-22
Also published as: NO311750B1; NO996473L; NO996473D0; GB0031378D0; NL1016985A1; GB2359773B; NL1016985C2

Description

1 2359773 METHOD AND DEVICE FOR MACHINING OF SUBSTANTIALLY ROUNDED BODIES,

SUCH AS PIPES The present invention relates to a process and a device for machining of bodies, such as pipes, as described

in the introduction of the subsequent claims 1 and 7.

More particularly the invention relates to a process (and a device) for machining of an elongated, substantially rounded body, in particular a pipe, or a substantially cylindrical body, where the the body or pipe more or less comprises dents or other deformations, where the body is clamped in an arrangementwhich can make the body rotate around its longitudinal axisi and a cutting tool, particularly comprising a cutting edge, is brought into contact with the body surface to generate the machining The invention also relates to a use of a method for cutting of pipes/bodies or for cutting a groove in the surface of a pipe.

Cutting a pipe by means of cutting edges is previously known. The cutting edge, which is fitted to a head, is arranged against the pipe which is then made to rotate. The cutting edge scratches or cuts into the pipe material and finally it goes through the pipe wall completely and a section of the pipe falls off. The cutting edge, which is fitted to a head, is normally comprised of a short sharply sharp-edged (honed) edge, and it is normally set across the direction of rotation of the pipe. Thus, the edge will dig, scratch or cut into the wall of the pipe. The pipe can either be cut off completely, or a groove can be made in the wall of the pipe.

2 There are, however, a number of disadvantages with this type of pipe cutting, due to the pipe never being completely circular or round. The pipes can be eccentric, they can be dented as a consequence of damage from impacts, or have other smaller irregularities. Such inconsistencies, dents and irregularities often result in the cutting edge breaking through the wall at different places at different times. Therefore, the cutting edge will easily be damaged or broken by the rotating pipe.

Furthermore, problems are created when cut-off shavings are "wound" off from the pipe during the cutting. Such shavings are normally in the form of a continuous, spiral-shaped string, and become gradually longer and longer as the cutting progresses. The shavings can in the end wind themselves around the pipe or part of the apparatus and cause problems for the operation. The spiral shavings can, therefore, be dangerous for the surroundings. It is normal to cut pipes of the abovementioned type using a band saw. However, this method often gives an uneven cutting-face and it is easy for the saw blade to cut out to the side, in which case the piece of pipe will need post -processing, or in the worst case, that it must be discarded. Furthermore, the method is time consuming. For a pipe of a given thickne ss and diameter, for example of up to 150 mm, the time consumption can be up to 6-7 minutes. It is an object of this invention to provide a new solution for such a device for cutting of pipes of the abovementioned type, and which can prevent damages to the cutting edge. 30 It is also an object of the invention to be able to reduce the time it takes to cut such pipes. Furthermore, it is an object of the present invention to eliminate the problems with the cut-off shavings which are wound f rom the pipe. 35 The invention is particularly suited for machining of thin-walled pipes with a wall thickness of 2-6 mm, particularly 3-4 rnin, which are easily exposed to damages during transportation.

3 The process according the invention is characterized by a sensor/ adjustment device is arranged to control/regulate the positioning of the cutting edge of the cutting tool in relation to the surface contour of the body, and thereby also control the cutting depth of the cutting edge into the body wall, and the sensor - /adjustment device is kept in constant contact with the surface of the body.

The device according the invention is characterized by the features which are described in the characteristics of claim 7.

Preferred embodiments of the process and device are described in the dependent claims, respectively.

Consequently, a solution for a controlled cut through the pipe wall is provided with the invention, as the cutting steel will follow the rolling movement of the runner-wheel (they are connected to each other) into and out of all the depressions and over all possible protuberances which inay be found along the pipe surface.

Furthermore, as the runner-wheel lifts the cutting steel out from its contact with the pipe wall at each turn of the wheel and momentarily cancels the cutting effect of the cutting steel, there will be a break in the abovementioned formation of shavings. The shavings are thereby broken into shorter lengths and falls down without representing any danger to the surroundings.

Compared with previous band saw methods, as mentioned above, in which it may take 6-7 minutes to cut a pipe of 150 mm in diameter and 3-4 mm. thick, a corresponding pipe can now be cut in 20-30 seconds, something which implies a considerable time saving.

There are many practical embodiments whereby one can obtain such operation of the unit of cutting edge (cutting steel) and runner-wheel, most of these shall be described briefly, whilst one of these possible embodiments shall be described in more detail with reference to the enclosed figures in which:

Figure 1 shows in perspective an example of an embodiment of the invention.

1 4 Figure 2 shows a side sketch of the mutual Positioning of the cutting steel and runner-wheel and the pipe that is to be cut.

Figures 3a-c show three possible embodiments of a runner-wheel seen in cross section.

Figures 4a-d show side sketches, partly in outline, of how the cutting head is moved forward in a three step continuous forward movement of the cutting edge/steel in relation to the runner-wheel. Thus, figure 4a shows the start of the cutting operation, while figure 4d shows the situation in which the runner-wheel pulls the cutting edge out from its cutting operation.

Figures 1 and 2 show schematically an example of an embodiment of the invention.

Figure 1 shows a cross-section of a pipe 10 (which generally is denoted a body) with a given pipe thickness. The outer surface of the pipe is shown by 11 and its centre is shown by 15. On the whole, the pipe 10 is circular, but includes a depression or a flat part, shown by 18, which can be a result of some damage from an impact etcr or there can be small protuberancese or misalignments (so-called eccentricities) in the pipe along its longitudinal direction.

The pipe 10 is secured in a clamping device, comprising four, previously known, elongated drive rollers 12,13,14,15, (for example arranged with 900 (degrees) mutual distance around the periphery) and which can rotate the pipe in the direction 16 around its longitudinal axis 15. The pipe driving gear is preferably placed as near to the cutting head as possible.

The cutting device 20 comprises two elongated arms 22,24 of approximately the same length, 'which are mounted so that they can swing around a swing axis 25 in a base section part 27. The axis through the swing point runs parallel to the longitudinal axis of the pipe. On the whole, the arms 22, 24 extend vertically upwards from the base 27. Fitted on the f ree extreme end of the one arm 22 is a cutting head 23 with a cutting ineans having a sharply honed contact edge 26 inserted, hereafter called a cutting steel. The cutting head 23 with the cutting steel 26 can be moved forward to make contact with the surface 11 of the pipe 10. This arm is hereafter called the cutting steel arm 5 22.

A runner-wheel 30 is mounted on the extreme end of the other arm 24, and this arm is hereafter called the runnerwheel arm 24.

The runner-wheel 30, a roller or the like, is arranged to roll freely against the pipe 10 which is to be processed, and which shall help to keep the steel 26 in a correct position against the surface of the pipe. The surface of the runner-wheel has a roughness such that the wheel will run against the pipe surface. According to an alternative solution, the runner-wheel can be replaced by a device, such as a slide, which only glides against the surface of the pipe, and is in constant contact with this surface. Thus the runner-wheel 30 assembly operates as a sensor /adjustment device controlling the pipe cutting. 20 The runner-wheel 30 is preferably arranged close to the cutting head, with a suitable distance being, for example, about 5 mm or less. The mutual sideways distance between the cutting head 23 and the runner-wheel is illustrated in figure 2. At the starting-point, the cutting steel arm 22 and the runner-wheel arm 24 are rigidly connected to each other, in that the arms 22,24 are joined together at their head parts. The arrangement comprises means which can movelflip the cutting steel arm 22 forward around the swing axis 25 (towards the left in the figure) relative to the runner-wheel arm 24. This can be carried out with the aid of a wheel 32 at the end of a threaded rod in connection to the steel cutting arm 22, and which makes contact with corresponding threads on the runner-wheel arm 24. By turning the wheel 32 one way, the cutting steel arm 221edge 26 is (related to the runner wheel arm) moved forward towards the outer surface 11 of the pipe or further into the pipe material, while, by turning the other way, it will 6 pull back the arm 22. At the same time, the runner-wheel 30 of the arm 24 maintains a constant contact with the outer surface of the pipe.

Adjacent to the mounting point 25 of the base 27, the two arms 22,24 are connected to a horizontal-alarm 38 which forms an angle of about 90' with the arms 22,24.

An end part 41 of the arm 38 is connected to the surface 42 of the base 27 via a spring element 43. The spring element 43 will force the horizontal-alarm 38 upwards and the unit of the cutting steel arm 22 and the runner-wheel arm 24 will correspondingly be pressed against the pipe surface with a given normal force. Alternatively the spring can be exchanged with a piston and cylinder unit which can regulate the contact pressure of the arms against the surface 11 of the pipe 10 hydraulically.

The base 27 comprises a movable part 42 which can be moved forwards (i.e. to the left in the figure) and backwards, to regulate the horizontal setting of the unit 22124 in relation to pipes with different diameters. The base section 42 slides along a track and can be moved forwards and backwards by turning a fixed axis 46 which is further connected to the base 48 of the apparatus which is fixed to the floor. The axis is fitted with threads which fit corresponding threads in the underside of the base 42.

The axis is turned by means of the wheel 44. This construction is used to pull the cutting apparatus back (towards the right) when a new pipe is clamped in, and to lead the cutting apparatus back to its position at the surface of the pipe when the pipe is ready to be cut.

To cut a pipe, the rotating mechanism 12,13,14,15, is started such that the pipe 10 rotates at a suitable speed.

The sharply honed edge 26 of the cutting steel is arranged along the axis of rotation of the pipe such that the edge 26 cuts (or scratches or digs) across into the pipe material when the arm 22 is pushed/pivoted towards the rotating pipe 10.

The wheel mechanism 32 is used solely to regulate the mutual positions of the runner-wheel and cutting steely 7 while there are many ways to obtain the necessary pressure exerted by the cutting steel on the pipe to achieve the cutting effect.

When the pipe 10 rotates, the roll/wheel 30 will roll on the surface of the pipe and all the time be forced against the surface of the pipe because of the effect of the spring element 43. The running- wheel arm 24 comprising the wheel 30 will thereby follow the surface of the pipe so that the cutting edge 26 will all the time (i.e. as long as the mutual displacement between wheel 30 and cutting edge 26 is not changed) have the same distance from the surface of the pipe, independent of the shape or form of the pipe.

As can be seen in figure 3a, the runner-wheel 30 has an elevation 34, bead or the like. Figure 3b shows a runner-wheel with a spiral-shaped surface contour, i.e. from a maximum diameter it has a gradually decreasing diameter along the wheel circumference to the point of the maximum diameter. Thereby, a sharp edge 36, or ledge, is formed along the peripheral circumference of the runner- wheel. Figure 3c shows a wheel which is eccentric.

With these wheel shapes, the runner-wheel will make small ejumpsD back and away from the surface of the pipe, while the cutting steel arm 22 will be lifted out from its contact with the pipe wall 11. The cutting steel is thereby removed from its cutting action and there will be a break in the abovementioned formation of shavings.

it can be seen that the arm 24 with the runner-wheel 30 forms a sensor /adjustment device for the positioning of the cutting head 23 with its cutting edge 26.

Functions of the apparatus.

When a pipe is to be cut, it is brought into position in between the rotating rollers as shown in figure 1, the unit cutting head/ runnerwheel 26130 is placed in correct position in relation to the pipe which is further moved in a longitudinal direction to a correct position so that the correct length of pipe can be cut. The pipe is set to rotate and the cutting device with the cutting steel 26 is 8 moved forward to make contact with the pipe by turning the screw-wheel 32. The runner-wheel 30 is pushed against the outer wall of the pipe with a given pressure. The contact pressure of the cutting edge 26 against the surface of the pipe is set at a somewhat lower contact pressure than the corresponding pressure for the runner-wheel so that the runner-wheel shall lie against the outer wall of the pipe and carry out its intended control function and secure an even cutting of the pipe wall by the cutting edge.

The runner-wheel contributes to the cutting edge 26 keeping a steady contact pressure against the surface of the pipe with respect to the bottom of the groove 31 which is being cut. The cutting edge 26 will, as it is rigidly connected to the runner-wheel, follow the movements of the runner wheel all the time. Further, the runner-wheel maintains a constant contact pressure against the surface of the pipe during the cutting process and also ensures that the cutting edge follows the irregularities in the pipe surface. As the groove 31 is cut into the pipe material, the cutting head is gradually, or continually (at an even speed), moved forward in relation to the runner wheel 30. The gradual forward movement of the cutting steel 26 in relation to the runnerwheel 30 and the pipe 10 itself, is shown in four stages in figure 4.

Consequently, the cutting edge cuts a groove 31 deeper and deeper into the pipe wall material and finally completely through it, so that the section piece of pipe falls off. A first step a) 4ccording to figure 4, shows cutting edge and runner-wheel side by side, i.e. before the cutting operation itself starts. In step b) the cutting edge is moved somewhat further forward and has cut halfway through the pipe wall. In step c) the edge is moved even further forward, and will now cut through the wall completely.

The problem with the steadily longer spiral-shaped shavings from the cut, shown by 50 in figure 4, which will increasingly be slung around in larger and larger circles, is now solved as the outer periphery of the runner-wheel 30 9 comprises a shorter or longer elevation (bead) which will contribute to the arm being pushed outwards from the pipe surface. Thereby, the cutting edge will also be pulled from the pipe wall, or a bit out of the groove, and thereby out from its cutting function. Thereby, the off-cut shavings are broken and fall down. As the runner wheel 30 has a small diameter compared to the pipe 10, the wheel 30 will make many turns for each turn of the pipe and will produce many shorter bits of shavings falling down for each turn of the tube, without these shavings representing any danger.

Another preferred constructional alternative in relation to that which is shown and described in figure 1, is that the unit of the runner-wheel 30 and cutting steel head can be fitted on a slide which, for example, can be moved along a rail, and by means of hydraulically driven piston and cylinder units one can:

1) Move the slide unit forwards and backwards on the track, i.e. up to and away from the pipe surface, 2) regulate the contact pressure against the pipe surface, and 3) regulate the mutual positioning of cutting edge 26 and runner-wheel 30, and their mutual contact pressure against the pipe surface.

When a longer pipe shall be cut into a number of smaller pipe lengths, the pipe is located on a forward feeding table, which both positions the pipe so that it is cut into correct lengths and also that there is an automatic forward feeding between each cut. The operation of the forward feeding mechanism is tied to the operation of the cutting tool itself such that the whole cutting process can take place automatically.

The process and device according to the invention can also be used when the pipe is not to be cut completely, but only a groove with an optional depth is to be made in the surface of the pipe. Thus, a groove can also be made in the surface of solid, circular, or approximately circular (round), solid bodies such as cylinders, rods and the like.

According to the invention, a new construction is thereby provided for machining oblong working pieces, something which results in improved operation of such apparatus, and gives increased safety for the operators. The invention may be used for machining solid bodies or pipes of several cross section shapes, such as circular, rounded or oval shaped cross sections.

11 P A T E N T C L A 1 M S.

1. Process for machining of an elongated, substantially rounded body, in particular a pipe (10), or a substantially cylindrical body, where the the body or pipe (10) more or less comprises dents or other deformations, where the body (10) is clamped in an arrangement (12 15) which can make the body rotate around its longitudinal axis, and a cutting tool (22), particularly comprising a cutting edge (26), is brought into contact with the body surface to generate the machining, characterized in that a sensor /adjustment device (24,30) is arranged to control/regulate the positioning of the cutting edge (26) of the cutting tool (22) in relation to the surface contour of the body (10), and thereby also control the cutting depth of the cutting edge (26) into the pipe wall, and the sensor/adjustment device (24,30) is kept in constant contact with the surface of the body.

2. Process according to the claim l, characterized in that the cutting edge (26) of the cutting tool (22) is moved forwards in relation to the sensor/adjustment device (24, 30) towards the wall of the body which is to be machined/processed.

3. Process according to claims 1-2, characterized in that as a sensorladjustment device (24,30) an arm (24) with a runner-wheel (26), or a gliding device, which is brought into contact with the surface of the pipe, is used.

4. Process according to claims 1-3, characterized in that the movement is carried out by rotation of a threaded rod in connection with the cutting edge arm (22) where the rod engages with corresponding threads on the runner-wheel arm (24) so that the cutting edge (26) is moved forward.

1 12 5. Process according to one of the preceding claims, characterized in that the cutting edge (26) regularly or irregularly (with time intervals) is brought out from the cutting action against the body material to break the cutoff shavings (50).

6. Process according to claim 5, characterized in that a runner-wheel (30) with a spiral-shaped surface contour is used, i.e. that from a maximum diameter it has a gradually decreasing diameter along the wheel circumference up to the maximum diameter point in which the surface enlarges with a sharp edge, or that the runner-wheel is eccentrically fitted to the flip arm.

7. Device for machining of an elongated, substantially rounded body, in particular a pipe, or a substantially cylindrical body, where the the body or pipe (10) more or less comprises dents or other deformations, in which the device comprises an arrangement (12-15) for clamping of the body (10), an arrangement for rotating the body around its longitudinal direction, and a cutting tool (22), particularly comprising a cutting edge (26), which can be brought into contact with the surface of the body to generate the machining, characterized in that a sensor /adjustment device (24,30) is arranged to control/ regulate the positioning of the cutting edge (26) in relation to the surface contour of the body (10), thus to control the cutting depth of the cutting edge (26) into the body wall, 30 that the sensorladjustment device (30) is in constant contact with the surface of the body.

8. Device according to claim 7, characterized in that the sensor/adjustment device (24) comprises a runner-wheel (a.

roller) (30) arranged to roll on the peripheral surface of the body when the body (10) rotates, with the runner-wheel (30) being connected to the cutting tool (22,26).

13 9. Device according to claims 7-8r characterized in that to effect the cutting operation, the cutting tool (22) with its cutting edge (26) (a cutting steel) can be brought forward, in relation to the runner-wheel, towards the body wall which is to be machined.

10. Device according to claims 79, characterized in that the cutting tool (22,26) and sensor/adjustment device (30) comprise separate arms (22,24) the one end of which comprises the cutting edge (26) and the runner-wheel (30) respectively, that the other ends of the arms (22,24) are fitted so that they can swing around an axis (25) in a base secion (42), that the arms are in the starting point mutually connected to each other, and that the cutting edge (26) is, relative to the arm (22), arranged to be moved forward against (or into) the wall of the pipe (10) by the arm (24) being pushed/flipped around the axis (25).

11. Device according to claim 10, characterized in that the arms (22,24) are arranged to be clamped against the surface of the body (10) with a given f orce by means of clamping means, such as a spring element (43) or by hydraulic means.

12. Device according to one of the preceding claims 7-11, characterized in that the arms (22,24) Including the cutting tool (26) form the one leg unit of an L-shape, and which is fitted to the base section (42) so that it can be flipped around an axis (25), with the end part of the other leg in the L-shape being connected to the base via clamping means, such as a spring (42), thus to generate the clamping force of the arms (22,24) against the body.

14 13- Device according to one of the preceding claims 7-12, characterized in that the unit of the runner-wheel arm (30) and the cutting edge arm is fitted on a slide which can be moved along a rail.

14. Device according to claim 13, characterized in that the device comprises piston- and cylinder units which are arranged to:

1) move the slide unit forwards and backwards on the rail, i.e. up to and away from a body outer surface, 2) regulate the contact pressure against the body surface, and 3) regulate the mutual positioning of the cutting edge (26) and runner- wheel (30), and their mutual contact pressure against the body surface.

15. Device according to one of the preceding claims 7-14, characterized in that the device comprises means (30) for regularly or irregularly moving the cutting tool out from its body cutting action.

16. Device according to claim 15, characterized in that the means involves that the runnex-wheel (30) comprising along its peripheral circumference a number of protuberances (34), preferably two protuberances, or most preferably one protuberance.

17. Device according to claims 15-16, characterized in that the means comprise of the runner-wheel (30) having a spiral-shaped surface, i.e. that from a maximum diameter it has a gradually decreasing diameter along the wheel circumference up to the maximum diameter point at which the surface enlarges with a sharp edge, or that the runner- wheel is eccentrically mounted to the flip arm.

19. Use of the process and device according to the preceding claims for cutting a pipe.

19. Use of the process and the device according to the preceding claims for cutting a groove (31) in the outer wall of a pipe, or in the outer wall of a solid body.

20. Process for machining an elongated, substantially rounded or cylindrical body, substantially as hereinbefore described with reference to the accompanying drawings.

21. Device for machining an elongated, substantially rounded or cylindrical body, substantially as hereinbefore described with reference to the accompanying drawings.