A GUIDE FOR A CUTTING BAND

Abstract: In order to guide a cutting band in a band saw machine in a more efficient manner one or two pivotal band guides (1) according to the invention are fitted as close as possible to the cutting place. Each guide (1) is in two parts and designed as a wheel which can run on bearings (5). The wheel consists of two guide rings (2, 3) with side faces (10) forming lateral guides for the side faces of the saw blade (17) or the knife blade (11). At the rear the cutting blade is provided with a bottom guide in the form of a face (13, 19). This may be configured as the periphery of the rings (12, 18, 21). Finally, one or a number of tolerance rings (14, 20) are inserted, permitting adjustment of the distance between the sides faces (10) on a continuous basis. Hereby is obtained a rotary guide (1) which is not exposed to irregular wear since the entire guide is easily brought to rotate when the cutting blade is moved. This gives a hitherto unobtainable good guiding since the cutting band is being guided in all directions of tension during cutting, whereby deformation of the band is avoided. This gives a very accurate guiding without noise and with reduced wear of the cutting band.

Description: A GUIDE FOR A CUTTING BAND The invention relates to a guide for an endless cutting band in the form of a saw or knife blade running over at least two wheels in a cutting machine. When cutting by means of band saws and band cutting machines it is a large problem that the cutting band does not move in a sufficiently calm manner and that it does not remain in the same cutting position. This is due to the fact that the guiding of the cutting band is not effected close to the item to be cut but rather by the rollers placed nearest to the workpiece on which the band runs. This often creates a large span which causes the band to twist and bend when loaded during operation. This causes an unsteady cutting which is therefore not particularly accurate while at the same time producing a lot of noise. Add to this the load to which the band is subjected which often requires a more powerfully dimensioned cutting band which in turn causes it to become more expensive, creates greater saw kerfs and in¬ creases energy consumption. It is known to provide such band cutting machines with guide means in the form of a supporting roller on each side of the band and a roller towards the rear of the band. These known supporting rollers are, however, quick¬ ly worn and must therefore often be adjusted or replaced; also scattered wear traces often occur on particularly the rear supporting roller since the rollers must be brought to rotate individually by friction with the band. This results in an unsteady performance of the band and as already mentioned in more frequent replacement of the rollers. It is the object of the invention to overcome these shortcomings and disadvantages of the known cutting machines and guide means, and this is obtained by a guide comprising two guide rings fitted on the cutting machine, the said rings being assembled and being freely rotatable on a shaft and having side faces opposed to each other between which the rear portion of the cutting band can run, which side faces extend parallel to each other on a plane at right angles to the axis of rotation of the rings and at a distance to each other which is slightly larger than the thickness of the cutting band, and in that the guide rings at the interior of the side faces are provided with a bottom face or with one or a number of bottom rings against which the rear edge of the cutting band can run. Hereby is obtained a hitherto unknown good guiding of a cutting band, first and foremost because the guide is made up of a rotary unit which is easily brought to rotate by the friction against the band. The rotation of the guide means ensures that sporadic wear of the guide faces will never occur and that performance remains steady permitting accuracy and a cutting of a hitherto unknown good quality. The guide can be fitted close to the workpiece whereby the most accurate cutting is obtained. Guiding is furthermore performed without any significant noise development, and since the loading of the band is reduced, the band can be given smaller dimensions which makes it cheaper to produce and operate. As presented in claim 2, by making the contact faces hard-wearing, i.e. harder, friction against the band is considerably reduced thereby prolonging the life of the band. As presented in claim 3, by arranging exchangeable spacing or tolerance rings between the guide rings, the guide can be adjusted to any required band thickness and, when worn one or a number of the rings can be replaced or removed. As presented in claim 4, by using a V-shaped groove with a double-edged band knife, a hitherto unknown good guiding is obtained especially behind the band without damaging the cutting edge. As presented in claim 5, by fitting a scraper plate inside the guide groove, this can be kept free from cutting refuse, thus maintaining the contact of the band to the guide faces. Finally it is expedient, as presented in claim 6, to fit a dust collecting plate on each side of the band in order to keep the band clean. In the following the invention will be described in closer detail with reference to the drawing, in which fig. 1 is a sectional view through a guide for a double- edged knife blade, fig. 2 is a section of the cutting knife band between the guide faces and the V-groove, fig. 3 is a sectional view through a double guide for a double-edged knife band, fig. 4 shows this double guide seen from above, fig. 5 is a sectional view through a guide for a band saw blade, fig. 6 is a partial section through this guide seen from the side, figs. 7 and 8 are sectional views through two examples of guides with hardened steel wearing parts, fig. 9 is a sectional view through a guide with ceramic wearing parts, fig. 10 is a sectional view of a guide with a recess at one side face, figs. 11 - 12 are sectional views of a guide mean with a double recess, figs. 13 and 14 are sectional views of a guide with cleaning plates, fig. 15 is a sectional view through this guide, and fig. 16 shows this guide seen from above. Figs. 1 and 2 show an example of a rotary guide 1 which is mounted on a shaft 6 which can be attached to a machine part. An example of such a fitting is shown in fig. 4 where the shaft 6 is attached to a machine part 16 by means of a nut 15. On the shaft 6 two ball bearings 5 are arranged having an intermediate ring and being attached in a manner known per se by means of a bolt 8 at the end of the shaft, as shown in fig. 1. On the outside of the bearings 5 a hub 4 is provided which is held by means of a locking ring 7 in an interior groove in the hub. At its end the hub 4 is provided with a flange forming one of the lateral guide rings 3 which on the outside forms a side face 10. The opposite side face is formed in a guide ring 2 being attached to the hub 4 by means of a nut 9. Between these lateral guide rings 2, 3 there is provided a recess for a pair of wearing rings 12 each having a bevel 13 extending on a plane at right angles to the axis of rotation and in the centre of the two lateral guide faces 10. Finally, one or a number of distance rings 14 are provided between the steel rings 12. All the mentioned parts on the hub 4 are tightened together by means of the nut 9 in such a manner that the parts form a wheel which easily turns on ball bearings on the. shaft 6. The guide shown in figs. 1 and 2 is especially suited for double-edged knife bands 11 in that this allows the band to be laterally guided by means of the side faces 10, and at the rear edge by the V-groove formed by the bevels 13 in that, as shown more clearly in fig. 2, guiding and control is effected on both sides of the knife edge without causing damage to the edge proper, because this extends in the groove between the rings 12 which by means of distance rings 14 are at a certain distance to each other. In this manner a double-edged band can be guided and supported at its rear edge, thus ensuring a good support during the cutting of the band. Fig. 3 shows an example of the use of the guide shown in figs. 1 and 2 for construction of a double guide for a double-edged cutting band 11. As is seen from fig. 3, the guides 1 are slightly staggered in the direction of motion of the knife in order to guide both knife edges in the two V-grooves 13 just as the sides of the knife 11 can be guided in the full width of the knife by the two sets of lateral guides 10. Figs. 5, 6 and 7 show an embodiment of a guide 1 whose side piece is formed by side faces 10 being arranged directly on the side rings 2, 3. These rings 2, 3 can be made of a lighter material such as aluminium, and the side faces 10 can be configured as a hard wear-resisting coating thereon. The end guide face or bottom face 19 is a steel ring or a similar hard material 18 which is held in a recess and with a distance ring 20 at the side for the formation of the required distance between the side faces 10, corresponding to the thickness of a saw band 17, which is thereby allowed to run just between the lateral guides 10. Instead of aluminium the rings 2, 3 can be made of hardened steel. Fig. 8 shows an example of a guide made of a light material, such as aluminium which is subsequently provided with wearing rings 23 for the formation of the lateral guides 10, and with a ring portion 18 for the formation of the rear guide face 19 for the rear edge of the saw band 17. Fig. 9 shows an example of a guide with aluminium guide rings 2, 3 which are provided with a ceramic coating 21 at one side and which furthermore have a ring portion at the interior for the formation of the bottom guide face 19, and which at the other side are provided with a ring 22 for the formation of the opposite wear face. Also here one or a number of distance rings 20 are provided for adjustment of the distance between the lateral guide faces 10. Fig. 10 shows an example of a guide 1 without recess in the one lateral guide 3. The recess is found only in the other lateral guide 2 so that the steel ring 18 can be inserted for determination of the width between the lateral guide faces 10 and the bottom guide face 19 for the saw blade 17. Working of the one lateral guide 3 is hereby recuced which simplifies manufacture of the guide considerably. Such a guide is advantageously made of cast steel which is subsequently hardened. Finally, figs. 11 and 12 show an example of a guide 1 with lateral guide rings 2, 3 whose recess is uniform and so wide that steel rings 18 with different largest diameters can be inserted for the formation of the bottom face 19 which can be adapted to saw bands 17 of varying widths. Hereby is obtained a universal guide equipment in which distance rings 20 can be inserted as previously mentioned. If such materials are to be cut which tend to deposit either in the guide groove or on the band, it is an advantage to fit a cleaning device, as shown in figs. 13- 16. A holder 24 is secured on the shaft 6, and to this holder there is attached partly a dust collecting plate 25 extend¬ ing down into the guide groove behind the saw band 17 as shown in figs. 13 - 16, and partly a dust collecting plate 26 extending on both sides of the band 17 thereby cleaning the band of dust and other refuse, such as saw meal during operation. In this manner the guide can be used for cutting knives or cutting saws in slaughterhouse machinery or the like, thereby eliminating any risk of disturbing the performance of the guide or the band. By means of this guide there is thus ensured the best possible cutting accuracy since all parts rotate simultaneously and easily by friction with the band when this runs. Irregular wear is hereby avoided and the optimum rotation symmetrical faces remain intact. This also gives low noise and, as already mentioned, a hitherto unobtainable steady running of the band thus facilitating a precise cutting operation. As one or more of the parts are worn the equipment is easi¬ ly disassembled permitting replacement or partial removal of distance rings so that the distance between the lateral guide faces is constantly adapted to the thickness of the band.

Claims: C L A I M S 1. A guide for an endless cutting band in the form of a saw or knife blade running over at least two wheels in a cutting machine, c h a r a c t e r i z e d in that each guide (1) comprises two guide rings (2, 3) fitted on the cutting machine, the said rings being assembled and being freely rotatable on a shaft (6) and having side aces (10) opposed to each other between which the rear portion of the cutting band (11, 17) can run, which side faces (10) extend parallel to each other on a plane at right angles to the axis of rotation of the rings and at a distance to each other which is slightly larger than the thickness of the cutting band (11, 17), and in that the guide rings (2, 3) at the interior of the side faces (10) are provided with a bottom face (13, 19) or with one or a number of bottom rings (12, 18, 21) against which the rear edge of the cutting band (11, 17) can run. 2. A guide according to claim 1, c h a r a c t e r ¬ i z e in that the side faces (10) and the bottom ace (13, 19) are provided with hard-wearing surfaces. 3. A guide according to claims 1 and 2, c h a - r a c t e r i z e d in that one or a number of distance rings (14, 20) are provided between the guide rings (2, 3) for adjustment of the distance between the side faces. 4. A guide according to claims 1-3 for use in a cutting machine with double-edged knife blade (11), c h a ¬ r a c t e r i z e d in that the bottom ring (12) is provided with a V-groove (13) for the rear cutting edge. (Figs. 1 and 2). 5. A guide according to claims 1-4, c h a r a c t e r ¬ i z e d in that a holder (24) is provided on the cutting machine (16, 6) said holder having a stationary plate (25 projecting in between the side faces (10) to the botto face (13, 19) behind the cutting band (11, 17) for th cleaning of the guide groove. 6. A guide according to claims 1-5, c h a r a c t e r i z e d in that a stationary dust collecting plate (26) i provided on the cutting machine on each side of the cuttin band (11, 17) for the cleaning thereof.

Inventors: HYLDIG JENS MARTIN HOVMOELLER, HYLDIG, JENS, MARTIN, HOVMOELLER
Applicants: HOVMOELLER HYLDIG J M, HYLDIG, JENS, MARTIN, HOVMOELLER
Application year: 1991
Main classification: B27B13
IPC codes: B23D55, B26D1