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Title:
ROLLER MACHINING METHOD AND MACHINING DEVICE
Document Type and Number:
WIPO Patent Application WO/2002/092282
Kind Code:
A1
Abstract:
The present invention concerns a method and device for machining roller conveyor rollers while they are installed in the roller conveyor. The rollers are machined using a machining device according to the present invention, having a support framework and a tooling guide bar (46) fastened to said support framework. The support framework has versatile adjusting possibilities, allowing it to be installed on top of different sized roller conveyors. The support framework is firmly fastened to the roller conveyor in such a way that the tooling guide bar is positioned over the roller conveyor in the longitudinal direction of the rollers. A cutter carriage (26) is fastened to the tooling guide bar by means of a sliding fastening mechanism and roller tolling means are arjustably fastened to said cutter carriage. A machining device according to the present invention is specially well suited for metal-shaving machining of rollers, where a lathe cutter or a milling unit is used as a tooling means, but also other tooling means can be attached to the cutter carriage. During machining the rollers are rotated in opposite directions using their own electric motors while the tooling means is moved on the tooling guide bar along the surface of the roller, whereupon the rollers are machined to the desired shape. With the method and device according to the present invention, two adjacent roller conveyor rollers can be machined simultaneously. the present invention is also especially well suited for machining of steel mill roller conveyors, but it may also be used for other similarly structured roller conveyors.

Inventors:
PEKKALA ESA (FI)
Application Number:
PCT/FI2002/000404
Publication Date:
November 21, 2002
Filing Date:
May 13, 2002
Export Citation:
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Assignee:
ASTP TEKNIIKKA OY (FI)
PEKKALA ESA (FI)
International Classes:
B21B28/02; B23B5/08; B23C3/04; B24B5/36; B24B5/37; B21B39/12; (IPC1-7): B24B5/37; B21B28/02; B23Q9/00
Domestic Patent References:
WO1997031755A11997-09-04
Foreign References:
SE458344B1989-03-20
GB2136716A1984-09-26
US5853318A1998-12-29
US2651152A1953-09-08
DE1596618B11971-03-11
Attorney, Agent or Firm:
OULUN PATENTTITOIMISTO BERGGREN OY AB (Lentokatu 2 Oulunsalo, FI)
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Claims:
Claims
1. A method for machining roller conveyor (10) rollers (12) while said rollers are attached to said roller conveyor, in which method a tooling device is moved along a tooling guide bar (46) in the longitudinal direction of said rollers (12), is character ized in that in said method at least two roller conveyor rollers are machined simulta neously and machining is performed using metalshaving tooling means, such as a lathe cutter (72) or a milling unit (82).
2. The method according to claim 1, characterized in that during machining the rollers (10) being machined are rotated using their own electric motors (18).
3. A roller conveyor (10) roller (12) machining device having a support frame work (22) and at least one tooling guide bar (46) attached to said support frame work, said tooling guide bar having a movable cutter carriage (26) for fastening tooling means, is characterized in that said tooling device has tooling means, such as a lathe cutter (72) or a milling unit (82) for metalshaving tooling of at least two rollers simultaneously.
4. The machining device according to claim 3, characterized in that said device also has a grinding unit for roller grinding.
5. The machining device according to claim 3 or 4, characterized in that said device has one tooling guide bar (46) and at least two tooling means (72,82) are arranged on the cutter carriage (26) for machining two adjacent rollers (12).
6. The machining device according to claim 3 or 4, characterized in that said device has more than one tooling guide bar (46) and at least one tooling means (72, 82) is arranged on the cutter carriage (26) for machining at least one roller (12).
7. The machining device according to one of the claims 36, characterized in that the cutter carriage (26) is fastened to the tooling guide bar (46) movably in the longitudinal direction of said tooling guide bar and said machining device has means (62,64) for moving said cutter carriage.
8. The machining device according to one of the claims 37, characterized in that the tooling means are fastened to the cutter carriage (26) by means of a sliding fastening mechanism (68,70) and said cutter carriage has an adjusting means, such as an adjusting screw (74), for moving the tooling device (72,82) toward the roller (12) being machined.
9. The machining device according to one of the claims 38, characterized in that the support framework (22) has means (32,36,38) for fastening said support framework to the roller conveyor (10).
10. The machining device according to claim 9, characterized in that the support framework (22) is arranged to be fastened to the roller conveyor (10) rollers (12) by means of support forks (32).
11. The machining device according to claim 10, characterized in that the support forks (32) are fastened to the support framework (22) movably in the longitudinal and transversal directions of the roller conveyor (10).
12. The machining device according to one of the claims 311, characterized in that the tooling guide bar (46) is fastened to the support framework (22) movably in the longitudinal and transversal directions of the roller conveyor (10).
Description:
Roller machining method and machining device The present invention concerns a method for machining roller conveyor rollers while said rollers are fastened to said roller conveyor, in which method a tooling device is moved along a tooling guide bar in the longitudinal direction of said roll- ers. The present invention also concerns a roller conveyor roller machining device, having a support framework and at least one tooling guide bar fastened to said sup- port framework, said tooling guide bar having a movable cutter carriage to which a tooling device is fastened.

In steel mills molten metal is poured through a chill to form a strip-like blank, after which said blank is rolled into its final shape. Before rolling, the metal blanks are preheated in an oven, after which the blanks are transferred to a roller conveyor, along which the blanks travel throughout the entire tooling phase. The roller con- veyors are constructed from partial roller conveyors having cylindrical metal rollers of the same size placed in parallel. The ends of the rollers are fastened to the frame of the roller conveyor by means of bearings, and the rollers are rotated by means of electric motors at one end of the rollers. The entire rolling line is constructed of sev- eral consecutive partial roller conveyors whose roller length and roller diameter vary as necessary.

The rollers usually are uniform in diameter, but because the rollers flex under the load of the heavy metal blanks passing over them, the rollers are sometimes ma- chined so they are slightly thicker, or cambered, in the middle. This way the upper surface of a roller in operation is level. Roller conveyor rollers are also often ma- chined so they are slightly conical and placed in the roller conveyor so the thinner ends of adjacent rollers face in opposite directions. Because of the conical rollers, a metal blank moving over the roller conveyor seeks its way toward the center of the roller conveyor and stays well on the roller conveyor. Roller conveyors are usually quite long; one roller conveyor may have several hundreds of rollers.

When the rollers of a roller conveyor wear, their cross-sectional shape changes, and the performance of the roller conveyor weakens. Because of this wearing the rollers occasionally need to be turned to restore their correct shape. To ensure that the roller conveyor functions optimally without disturbing"steps"and that the circumferential speed of each roller is the same, the diameter of all the rollers in a partial roller con- veyor must be equal. For this reason, if even one worn roller needs to be turned to a smaller diameter, all the rollers in the entire partial roller conveyor need to be ma- chined. For machining the rollers are removed from the roller conveyor and trans- ported to a machine shop. Correspondingly, after machining the rollers are trans- ported back to the plant and installed in the roller conveyor. Because of the time involved in removing, transporting and installing the rollers, only a few tens of roll- ers can be machined during a plant's week-long maintenance shut-down.

Several devices according to the prior art are known which are mainly suitable for on-site machining of cylinders and rolls of paper and board machines. Such devices are presented in reference publications FI 101687, FI 853945, FI 895696 and SE 501250. In these designs a roller machining device is supported in place between rollers that are close to each other and they are moved along the surface of the roll- ers being machined in the longitudinal direction of the rollers. The surface of the roller is conditioned by means of a grinding machine which belongs to the device and which is operated by means of a separate drive motor. Some of the devices de- scribed in the reference publications may also be equipped with a cutter unit or a milling unit suitable for metal-shaving machining. Reference publications US 1614097 and US 2651152 describe roller grinding devices in which grinding sur- faces are pressed against the surface of a roller and the roller is rotated around its own axis.

Grinding machines are only suitable for light machining of the surface of a roller, such as grinding and removal of minor unevenness. Because grinding belts and stones wear, it is difficult to control the amount of material removed during machin- ing. Therefore they are not at all suitable for machining unevenly worn roller con- veyor rollers requiring considerable tooling. Furthermore, all the tooling devices described in the reference publications are supported against the surface of the roll- ers, so as they move in the longitudinal direction of the rollers they follow the con- tour and unevenness of the surface. For this reason the devices cannot, even when equipped with a metal-shaving tooling unit, be used on roller conveyors whose roll- ers must be machined to an exact diameter and often so they are conical or cam- bered in shape.

From reference publication FI 75621 a grinding device for a drying cylinder of a paper machine is known, where a belt grinder is moved in the longitudinal direction of the cylinder along a guide bar. The guide bar is fastened to a felt roll next to cyl- inder being machined by means of a magnet or circular fasteners. From reference publication GB 2135609 also, a roller grinding device is known where a belt grind- ing device is moved in the direction of the roller along guide bars. A grinding device that moves along separate guide bars moves in a straight line, but grinding alone cannot be used to tool considerably worn rollers exactly to a desired diameter and shape. From reference publication DE 1596618 a roller cleaning device used in glass manufacturing is known, where rollers are cleaned by means of cleaning ele- ments which are moved along a guide bar. Said device is clearly intended only for light cleaning of roller surfaces and is not at all suitable for heavier machining of rollers.

The purpose of the present invention is to present a new method and machining de- vice especially for on-site machining of roller conveyor rollers. The method and ma- chining device according to the present invention significantly reduce the drawbacks and disadvantages related to machining devices and machining methods according to the prior art.

A method and machining device according to the present invention is characterized by what is presented in the independent claims. Certain advantageous embodiments of the present invention are presented in the dependent claims.

In the method according to the present invention the roller conveyor rollers do not need to be removed from the roller conveyor during machining, but instead the roll- ers are machined while they are installed in place in the roller conveyor. The rollers are machined using a machining device according to the present invention, having a support framework and a tooling guide bar fastened to the support framework. The tooling guide bar has a cutter carriage which moves in the longitudinal direction of the rollers and to which a tooling means are fastened. The support framework is in- stalled on top of the roller conveyor and firmly fastened to the roller conveyor so that the tooling guide bar is positioned in the direction of the longitudinal axis of the rollers being machined. Then the rollers are rotated around their longitudinal axes advantageously in opposite directions while the position of the tooling means is ad- justed so they rest against the surface of the rollers being machined. As the rollers rotate the tooling means are moved from the first end of a roller to the second end, whereupon the rollers are machined to the desired diameter and shape. The basic principle of the method according to the present invention is that two adjacent roller conveyor rollers can be machined simultaneously. This is possible using a machin- ing device according to the present invention having tooling means for simultane- ously machining at least two rollers at a time. In the method according to the present invention roller machining is performed using metal-shaving tooling means, such as lathe cutters or milling units.

In one advantageous embodiment of the method and machining device according to the present invention the roller conveyor's rollers are rotated in opposite directions by means of their own electric motors while the tooling device is moved along the surface of the roller.

One advantage of the method according to the present invention is that it is quick and efficient, because it allows simultaneous machining of two roller conveyor roll- ers at a time. Due to its efficiency a large number of rollers can be machined during a plant's maintenance shut-down.

Another advantage of the present invention is that it is suitable for metal-shaving tooling, whereupon even considerably worn rollers can be tooled to a desired diame- ter and shape on-site at the plant.

One advantage of the machining device according to the present invention is that it has diverse adjustment possibilities, which makes it possible to tool rollers to a conical or cambered shape, for example. Due to its adjustment possibilities the ma- chining device is suitable for machining different kinds and sizes of roller convey- ors.

Another advantage of the present invention is that it's structure is simple and func- tionally reliable and well suited to commercial production.

The present invention is described in detail below, with reference to the enclosed drawings, where figure la shows an exemplary presentation of a machining device according to the present invention viewed from one side, figure lb shows an exemplary presentation of a machining device according to the present invention viewed from above, figure 2a shows an exemplary presentation of part of a machining device according to the present invention showing a cutter carriage viewed from one side, figure 2b shows an exemplary presentation of part of a machining device according to the present invention showing a cutter carriage viewed from above, figure 3 shows an exemplary presentation of part of an advantageous embodiment of a machining device according to the present invention showing a cutter carriage viewed from one side, and figure 4 shows an exemplary presentation of part of another advantageous em- bodiment of a machining device according to the present invention showing a cutter carriage.

Figure la is an exemplary presentation of a roller conveyor 10 roller 12 machining device viewed from above. Figure 1b is a cross-sectional presentation of said ma- chining device viewed from cross-section A-A. Figures la and Ib also present the structure in principle of a roller conveyor 10 used in steel mills.

The roller conveyor 10 has frame beams 16 in the longitudinal direction of the con- veyor, with rollers 12 installed in the frame beams at regular intervals. The rollers are solid or tubular, long, cylindrical metal parts whose ends are shaped into axles.

The rollers are usually around 2,5 meters long and approximately 400 mm in diame- ter. The ends of the rollers are fastened by means of bearings to bearing housings 14 in the frame beams. The rollers are rotated from one end by means of electric motors 18 at the side of the roller conveyor, which are fastened to an outer frame beam 16 of the conveyor. There may be a gearbox 20 between the electric motors and the ends of the roller axles. To conserve space only a short section of a roller conveyor showing four rollers is presented in the figure. In reality, complete roller conveyors are very long structures having up to several hundreds of rollers. A machining de- vice according to the present invention is very well suited for machining roller con- veyors of steel mills, but said device may also be used for machining other types of roller conveyor rollers that are similar in structure.

In figures la and 1b a machining device according to the present invention is placed on top of a roller conveyor 10 in the position it is in when machining rollers 12. The machining device has a support framework 22 having two parallel support rails 30 in the longitudinal direction of the roller conveyor. The support rails are long enough to extend over at least four consecutive rollers. The ends of the support rails are fitted with support forks 32 resembling an upside down letter Y, having two slanting flanks facing downward and a stem facing upward. The support forks are the means with which the machining device is supported and fastened to the roller conveyor rollers during machining. The support forks are fastened near the ends of the support rails by means of a sliding fastening mechanism that allows the support forks to be moved along the support rails in the longitudinal direction of the support rails. The sliding fastening of the support forks to the support rails is important be- cause the spacing between rollers may vary in different parts of a roller conveyor and especially in different roller conveyors. The sliding fastening makes it possible to move the support forks so that both support forks of a support rail can always be exactly positioned over a roller.

In one advantageous embodiment of the present invention presented in figures la and lb, the sliding fastening of the support forks to the support rails is implemented by means of a bore 34 through the stem of the support fork through which the sup- port rail passes. The support fork also has a locking mechanism (not presented in the figure) with which the support fork can be locked to a locking rail. Said locking mechanism may be a bolt, for example, that is inserted in a threaded bore in the stem of the support fork. When the bolt is screwed into place the end of the bolt butts against the locking rail and locks the support fork into place. The sliding fastening of the support forks to the support rail may also be implemented in a different man- ner than the one described above.

The support forks 32 are fastened to the roller conveyor rollers 12 in such a way that two free rollers being machined are left between the support forks. The support forks are placed on top of the rollers 12 in such a way that the flanks of the support forks rest against the surface of the roller at two points. The support fork is fastened to the roller by means of a fastening rod 36 and fastening bolts 38. The fastening rod is placed below the roller and the ends of the rod are fastened to the ends of the flanks of the support fork by means of the fastening bolts. The roller is squeezed between the flanks of the support forks and the fastening rod, whereupon the sup- port fork remains firmly in place. Naturally, the ends of the fastening rod and the flanks of the support fork have bores for the fastening bolts. The flanks of the sup- port fork and the fastening rod may also be shaped differently, for example, they may be curved, whereupon they rest against the surface of the roller over a longer distance. The support fork may also be fastened to the roller in a different way than described above.

Adjacent support forks of the machining device are connected to each other by means of two support beams 40 in the transversal direction of the roller conveyor.

The support beams are metal beams whose surface resting against the support fork 32 has a guide slot 42 in the longitudinal direction of the beam. The end of the sup- port fork has a guide part 44, which is shaped similarly to the guide slot and inserted in the guide slot. The sliding fastening implemented by means of the guide slot and guide part allows the support fork to be moved in the longitudinal direction of the support beam. The support beam also includes a locking mechanism (not presented in the figure) with which the support fork can be locked in the correct position on the support beam.

Viewed from above, the fore-mentioned parts together form a rectangular support framework 22 of the machining device. The support framework is placed on top of a roller conveyor and fastened into place in such a way that two rollers being ma- chined are left between the support forks. The support forks are positioned as accu- rately as possible over the rollers and near the ends of the rollers. Due to the sliding fastening mechanisms of the support forks described above, the support framework can always be adjusted to a suitable size even though the length and spacing of the rollers vary. The support forks are supported near the ends of the rollers because the roller conveyor rollers wear the least at their ends. Therefore the ends of worn roll- ers are very close to their original shape and size. If necessary, spacers (not pre- sented in the figure) can be placed between the surface of the roller and the flanks of the support fork, whereupon the support forks can be adjusted to the correct vertical position.

A tooling guide bar 46 is fastened to the support rails of the support framework in the longitudinal direction of the rollers 12. A cutter carriage 26 is fastened to the bottom surface of said tooling guide bar by means of a sliding fastening mechanism.

The first end of the tooling guide bar is fastened to a support sleeve 52 in the first support rail of the support framework 22 and the second end to a support sleeve in the second support rail. The support sleeves are tubular metal parts through which the support rails 30 pass. The support sleeves are able to move in the longitudinal direction of the support rails, which makes it possible to move the tooling guide bar exactly to the correct position over the rollers being machined.

To move the cutter carriage, the cutter carriage has a threaded bore 60 through which a feed screw 62, which is advantageously a trapezoidal threaded rod, passes in the longitudinal direction of the tooling guide bar. The first end of the feed screw is fastened by means of a bearing to an end plate 66 at the first end of the tooling guide bar and the second end of the feed screw is fastened to a feed screw drive mo- tor 64, which is advantageously an electric motor, at the second end of the tooling guide bar. As the feed screw is rotated by the drive motor, the cutter carriage moves in the longitudinal direction of the tooling guide bar. A ball nut bearing housing can be advantageously arranged in the bore 60, whereupon the friction of the feed screw is minimized and the cutter carriage moves easily and evenly. Naturally, the move- ment of the cutter carriage may be implemented in a different manner than described above, for example, using toothed wheels and toothed bars driven by a hydraulic motor.

Figure 2a shows an exemplary presentation of part of a machining device according to the present invention showing a cutter carriage 26 viewed from one side and fig- ure 2b shows the same part viewed from above. The tooling guide bar 46 is fastened to the support sleeves 52 by means of a sliding fastening mechanism in such a way that the support sleeves can be moved in the longitudinal direction of the tooling guide bar. In an advantageous embodiment of the present invention presented in figure 2a the sliding fastening is implemented using flanges 54 at the top edge of the tooling guide bar and projections 56 on the bottom surface of the support sleeve 52, which are bent to an angle and encircle the edges of the flanges. The flanges and projections fasten the tooling guide bar in place on the bottom surface of the support flange, but allow the support sleeves 52 to be moved in the longitudinal direction of the tooling guide bar. Naturally, there must be sufficient clearance between the flange and projection to allow movement. The support sleeve also includes locking means (not presented in the figure) with which the sleeve can be made immovable on the tooling guide bar. The sliding fastening of the tooling guide bar to the support sleeves may also be implemented in a different way than described above.

A cutter carriage 26 is fastened to the tooling guide bar 46 by means of a sliding fastening mechanism in such a way that the cutter carriage can be moved in the di- rection of the tooling guide bar. The sliding fastening is implemented in such a way that the tooling guide bar passes through a groove 48 in the top surface of the cutter carriage. The sides of the groove have triangular projections and the tooling guide bar has corresponding similar triangular grooves, which keep the cutter carriage in place on the bottom surface of the tooling guide bar, but allow the cutter carriage to move in the longitudinal direction of the tooling guide bar. Naturally, there must be sufficient clearance between the groove in the cutter carriage and the tooling guide bar to allow movement. Naturally, the sliding fastening of the cutter carriage to the tooling guide bar may also be implemented in a different way than described above.

Both sides of the cutter carriage have a vertical adjusting guide bar 68, which has an adjusting carriage 70 that moves in the longitudinal direction of the adjusting guide bar. The adjusting carriage is a fastening base to which a tooling device for machin- ing the rollers 12 is fastened. A machining device according to the present invention is primarily intended for metal-shaving tooling of rollers, where the tooling device is a lathe cutter or a milling cutter. Nevertheless, the present invention is also suitable for lighter tooling of rollers, such as grinding, whereupon the tooling device may be a grinding device or a grindstone. In the embodiment presented in figures 2a and 2b the tooling device fastened to the adjusting device is a metal lathe cutter 72. It is also possible to fasten two different kinds of tooling devices to the adjusting car- riage, for example a lathe cutter and a grinding device, whereupon the roller is first machined to the correct diameter and shape using the lathe cutter and then the sur- face is finished by grinding.

A machining device according to the present invention has two adjusting carriages for tooling devices to enable simultaneous tooling of two adjacent roller conveyor rollers. In machining the rollers the tooling devices are placed in a suitable position over the rollers being machined. For example, when using a lathe cutter the cutter is advantageously placed near the center of the cross-section of the roller. Because the distance between rollers may vary in different parts of the roller conveyor, and espe- cially in different roller conveyors, it is necessary to be able to adjust the distance between the tooling devices fastened to the cutter carriage as needed. In a machining device according to the present invention, this adjustment possibility is implemented by fastening the adjusting guide bars 68 to the cutter carriage 26 removably, advan- tageously using bolts, and by inserting separate metal adjusting plates 78 in a gap between the adjusting guide bar and the cutter carriage. By selecting a suitable num- ber and size of adjusting plates the distance between the tooling devices fastened to the cutter carriage. The adjustment of the distance between the tooling devices may also be arranged in a different way, for example, by fastening the adjusting guide bars 68 to the cutter carriage 26 by means of guide bars in the longitudinal direction of the roller conveyor.

The adjusting carriages are fastened to a flange 76 at the upper end of the adjusting guide bar by means of an adjusting screw 76 in such a way that the adjusting car- riage can be moved in the direction of the adjusting guide bar by turning the adjust- ing screw. It is also possible to fasten another type of adjusting device for the adjust- ing carriage, such as an electric or hydraulic motor, and the operation of the adjust- ing device may also be arranged to function automatically using a computer-based control device. By using a machining device equipped with a computer-controlled automatic adjusting device it is easy to machine roller shapes that are not straight, such as conical or cambered rollers.

In the method according to the present invention the support framework 22 of the machining device is fastened on top of the roller conveyor 10 in the manner de- scribed in the explanation of figures la and lb in such a way that the rollers being machined are left in the middle of the support framework between the support forks 32. By moving the support sleeves 52 the tooling guide bar 46 is positioned in the middle of the rollers and locked in place. After this the drive motor 64 is used to move the cutter carriage 26 of the machining device over the ends of the rollers be- ing machined and adjusting plates are used to adjust the tooling devices to a suitable position over the rollers being machined. In the embodiment presented in figures 2a and 2b the tooling devices are lather cutters 72, which are advantageously posi- tioned near the center of the cross-section of the roller.

When the machining device is in place the rollers 12 being machined are rotated in opposite directions. The rollers are advantageously rotated using their own electric motors 18. The rotating speed of the rollers is adjusted to suit the machining by means of possible gearboxes 20 belonging to the roller conveyor or by using a fre- quency converter (frequency converter not presented in the figures). If for some rea- son it is not possible to rotate the rollers using their own motors, a separate auxiliary motor can be used to rotate the rollers. As the rollers rotate the lather cutters are moved against the roller being machined by turning the adjusting screw 74 so that the cutters begin removing metal from the surface of the roller. After this the cutter carriage is moved at an even speed by rotating the feed screw 64 using the drive mo- tor 64 so that the cutter carriage moves from the first end of the roller to the second end, whereupon the lathe cutters 72 turn the roller to a cylindrical shape of uniform size along its entire length. Because the rollers being machined rotate in opposite directions, the shaving forces exerted on the lathe cutters partially negate each other.

This reduces the amount of stress exerted on the cutter carriage 26, tooling guide bar 46 and support framework. It is also possible to install a tank and a hose to the ma- chining device according to the present invention to supply cutting fluid (not pre- sented in the figure). The use of cutting fluid when turning metal is a generally known method that reduces the friction between the lathe cutters and the surface being machined, thereby improving the result of turning.

If the roller being machined is not worn very badly, the roller can be machined to the desired diameter with one run of the cutter carriage. If the roller conveyor rollers require heavy machining, the machining can be done by completing several turning passes. In such a case the cutter carriage is moved from one end of the roller to the other several times and each time the lathe cutter is adjusted a little closer to the centerline of the roller being machined. If the roller is to be machined to a cylindri- cal or cambered shape, the position of the lathe cutter is adjusted as the cutter car- riage moves by turning the adjusting screw. Naturally, a more accurate result is ob- tained if the adjusting carriage of the machining device is equipped with an auto- matic adjusting device. When the rollers are machined to the desired diameter and shape, the support framework is removed from the roller conveyor and moved along the roller conveyor to the next rollers being machined, where the fore-mentioned procedures are repeated.

Figure 3 shows an exemplary presentation of part of an advantageous embodiment of a machining device according to the present invention showing a cutter carriage 26 viewed from one side. In this advantageous embodiment of the present invention the tooling device fastened to the adjusting carriage 70 is a milling unit 82, which includes a milling cutter 80 rotated by its own actuator. In this embodiment machin- ing of a roller takes place using the same principle as when lathe cutters are used, except that now roller machining is implemented as milling lathe work. In milling lathe work the milling cutter is rotated in the opposite direction as the roller being machined, whereby clearly higher shaving speeds are reached than in ordinary turn- ing. Therefore, milling lathe work is suitable for machining where a large amount of metal needs to be removed. Machining time for one roller is about a half hour with milling lathe work and about two hours with turning.

Figure 4 shows an exemplary presentation of part of another advantageous embodi- ment of a machining device according to the present invention showing a cutter car- riage 26. In this advantageous embodiment of the present invention there are two separate, independently adjustable tooling guide bars 46, each with its own cutter carriage, which is moved by means of its own drive motor 64 and feed screw 62.

Furthermore, in this embodiment a joint is arranged in the support sleeve 52, which allows separate adjustment of the position of each end of the tooling guide bar. The joint divides the support sleeve in the vertical direction into two separate parts whose facing surfaces have fastening flanges 53a, 53b, which are fastened to each other by means of fastening bolts 57. The fastening bolt holes in the fastening flanges are elliptic, which makes it possible to fasten the flanges to each other in slightly different positions, whereupon the position of the end of the tooling guide bar changes in the longitudinal direction of the roller conveyor. It is also possible to install adjusting plates 55 of different thicknesses between the fastening flanges to change the vertical position of the end of the tooling guide bar. This possibility to separately adjust the ends of the tooling guide bar is necessary, for example, if the rollers being simultaneously machined are not exactly parallel or if parallel rollers are machined to conical shapes that get thinner at opposite ends.

Both cutter carriages 26 have a tooling device, advantageously a lathe cutter or mill- ing cutter, for machining one roller. Machining of the roller also takes place in this embodiment in the same manner as described in the explanation of the previous fig- ures, meaning that two rollers being machined are rotated in opposite directions us- ing their own electric motors and they are machine to the desired shape by moving the cutter carriage and the fastened tooling device in the longitudinal direction of the roller. The advantage of two separate tooling guide bars and cutter carriages is that it is easier to accurately position the cutter carriages over the rollers being machined.

The number of tooling guide bars in a machining device according to the present invention is not limited to two, but there also may be several, for example three tool- ing guide bars. The cutter carriages of a device equipped with several tooling guide bars do not necessarily need to be of the same kind, but rather they may be equipped with different kinds of tooling devices. For example, a machining device may have three tooling guide bars, with the outside tooling guide bars equipped with tooling devices for tooling one roller and the middle tooling guide bar equipped with tool- ing devices for tooling two rollers. It is obvious that the more tooling guide bars and attached movable tooling devices a machining device has, the sturdier and more du- rable the support framework of such a machining device must be.

A machining device according to the present invention can be equipped with several different kinds of actuators and automatic control devices that control the movement of the guide bars and tooling devices, which thus facilitate the operation and instal- lation of the device. The machining device may be manufactured from ready-made factory parts, such as linear guide bars and ball nut screws. In the fore-mentioned description the machining device is fastened on top of a roller conveyor, but it may also be fastened underneath a roller conveyor. The fastening position can be freely selected depending on which side has more free space for operating the device.

Certain advantageous embodiments of a method and machining device according to the present invention are described above. The present invention is not limited to the embodiments described above, but rather the inventive idea can be applied in a number of ways to the extent allowed by the enclosed claims.