The present invention relates to the field of sawing technology. It relates to a method for the production of a bimetallic saw blade, saw band, or circular saw blade as claimed in the preamble of claim 1. It also relates to input stock for a saw blade or saw band.
It has been known for a long time to produce saw blades or saw bands having teeth at the edge from two different metals, a steel adapted to the support function being used for the support band (in the case of elongated saw blades or saw bands) or the support disk (in the case of circular saw blades), and the teeth being made at least partly of a higher-grade alloy steel suitable for the cutting operations and long service life, e.g. high speed steel (HSS) (see, e.g., EP-A1-0 319 511 or EP-A2-0 566 560). In the past, different production methods, which have various disadvantages, have been proposed for such bimetallic saw blades or saw bands.
One method consists in welding a support band at a longitudinal edge to a strip of cutting material (HSS or the like) (see, e.g., U.S. Pat. No. 3,685,373 or U.S. Pat. No. 6,701,627) and, possibly after a few interposed rolling operations, in forming the desired tooth profile in the edge region of the welded-on strip by stock removal. In this case, the teeth may be made of the cutting material over the full circumference or may also be made partly of the cutting material (U.S. Pat. No. 5,091,264). The production and precise processing of the narrow strip of cutting material is comparatively complicated and leads to increased production costs. An additional factor in this respect is the fact that a considerable proportion of the cutting material is lost due to the stock removal when forming the tooth profile. Furthermore, the thermal loading on one side when welding on the strip leads to undesirable deformations of the bimetallic band, which have to be removed later in complicated rework steps.
In other methods, a block of support material having a central layer of cutting material is produced by powder-metallurgy or fusion processes and is then rolled down to a thin band and finally divided in half in order to obtain two subsequently workable support bands having a marginal region made of cutting material (U.S. Pat. No. 3,766,808 and U.S. Pat. No. 3,930,426). In these cases, the production of the band-shaped starting material involves comparatively high outlay, which results from both the production of the multi-layer block and the requisite rolling steps.
No less complicated are methods in which first of all strips of cutting material are welded in a planar manner onto both sides of a support band (U.S. Pat. No. 3,593,600).
Finally, for saw blades or saw bands, it is known from EP-A2-1 389 503 to produce input stock in which spaced-apart individual sections of a narrow band made of a cutting material are welded to the outer edge of a support band in order to form a respective base for a saw tooth to be prepared later. In this case, the sections may be welded directly onto the edge of the support band. However, it is also proposed to attach the sections in a sunk position in recesses in the support band. A disadvantage with this type of input stock is that, firstly, the support band having the welded-on sections of cutting material can only be manipulated with difficulty, because the welded-on sections result in an unevenly structured edge, and that, secondly, a comparatively high proportion of cutting material is lost when forming the teeth and has to be painstakingly removed. In addition, the positioning of the individual sections of cutting material at the edge of the support band for the joining process involves great difficulty.
The object of the invention is therefore to specify a method for the production of a bimetallic saw blade, saw band, or circular saw blade which is distinguished by simplification of the method and by a marked reduction in the material and production outlay compared with the known methods and to provide corresponding input stock.
The object is achieved by the features of claim 1 and of claim 18 in their entirety. The essence of the invention consists in the fact that, to form the teeth, holes are first of all made in the support band or the support disk in accordance with the tooth spacing, that small insertion plates made of the cutting material are then inserted into the holes, which are filled by said small insertion plates, and that finally the small insertion plates sitting in the holes are bonded at the edges to the support band or the support disk. Since cutting material is used only at the locations at which the teeth are subsequently formed, a substantial saving of cutting material can be achieved. Since small flat plates are inserted into the holes of the support band or of the support disk, these, small plates can be punched out of a metal sheet in a simple manner, or can be cut out in another way, which metal sheet can be produced and processed in a substantially simpler and more cost-effective manner than a narrow strip of cutting material, as used in the prior art. Since the small insertion plates are completely surrounded at the edges by the support band or the support disk, the thermally induced deformation of the band during the bonding (brazing, welding) is considerably reduced or completely removed.
The holes and small insertion plates may in principle have the most varied shapes. In particular their edge contour may be designed in such a way that not much cutting material is lost with regard to the subsequent shape of the teeth. With regard to the processing and bonding, simple edge contours having higher symmetry are advantageous. The holes and small insertion plates therefore preferably have the edge contour of a polygon (triangle, square, pentagon, hexagon, octagon, etc.). However, especially simple conditions are obtained if the holes and small insertion plates have a round, in particular circular, edge contour.
Materials as are known from the publications mentioned at the beginning and as are familiar to the person skilled in the art may be used for the support band or the support disk and the small insertion plates. The small insertion plates are preferably made of a hardenable tool steel, in particular a high speed steel, and are hardened after being bonded to the support band or the support disk.
However, it is also conceivable for the small insertion plates to be made of a carbide. In this case, brazing in particular is suitable for the bonding between small insertion plates and support band or support disk.
If a support band is used, it is advantageous for the processing if the holes are made in the inner region of the support band, because the thermally induced deformation is then minimized. The conditions become especially simple if a support band is used having a width which is greater than or approximately equal to twice the width of the finished saw blade or saw band, if the holes are produced on a center line of the support band, if the support band, after being bonded to the small insertion plates, is divided into two sectional bands of preferably the same kind along a parting line extending in the longitudinal direction and running in each case through the small insertion plates, and if the two sectional bands are processed by stock removal, with a respective tooth profile being formed. In this case, the support band is preferably divided into two sectional bands by means of laser jet cutting.
The holes may be made in the support band or the support disk in different ways. A laser cutting method, for example, is conceivable. However, it is especially simple and cost-effective if the holes are made in the support band or the support disk by means of a punching operation.
Compared with the narrow band from the prior art, the small insertion plates have the advantage that they can be cut out, in particular punched out, of a larger metal sheet of cutting material in a simple and cost-effective manner.
A preferred configuration of the method according to the invention is distinguished by the fact that the small insertion plates sitting in the holes are bonded to the support band or the support disk by brazing, in particular inductive brazing, preferably with copper brazing metal. If small insertion plates made of a hardenable tool steel are used in this case, it is especially advantageous and especially time-saving and energy-saving if the small insertion plates, after being brazed in place, are hardened using the heat resulting therefrom.
However, it is also readily possible for the small insertion plates sitting in the holes to be bonded to the support band or the support disk by welding, in particular by means of laser beam or electron beam.
So that the inserted small insertion plates are correctly positioned for further processing, it is advantageous if the small insertion plates, after being inserted into the holes and before being bonded to the support band or the support disk, are fixed in the holes. In particular, it has proved successful for the small insertion plates to be fixed in the holes by embossing.
The method becomes especially simple if, according to another configuration, in a single process step, the small insertion plates are punched out of a larger metal sheet made of cutting material and are inserted into the holes in the support band or in the support disk, or if, in a single process step, the small insertion plates are punched out of a larger metal sheet (30) made of cutting material, the holes are punched in the support band or in the support disk, and the punched-out small insertion plates are inserted into the holes in the support band or in the support disk.
The input stock according to the invention is based on a support band or a support disk made of a first metal and is characterized in that there are holes in the support band or the support disk, in that small insertion plates made of a cutting material are inserted into the holes, the holes being filled by said small insertion plates, and in that the small insertion plates sitting in the holes are bonded at the edges to the support band or the support disk.
Further configurations follow from the dependent claims.
The invention is to be explained in more detail below with reference to exemplary embodiments in connection with the drawing, in which:
Reproduced in
According to
According to
However, it is also conceivable to use small insertion plates 16 made of carbide, as used for cutting tips for example. The small insertion plates 16 preferably have the same shape and edge contour as the holes 15, so that they completely fill the holes 15 and bear closely with their outer edge against the inner edge of the holes 15. During the subsequent bonding, the small insertion plates 16 are then connected to the support band 11 over the entire length of their edge. In particular with regard to the subsequent tooth shape, however, the small insertion plates 16 may also be shaped in such a way that they bear against the support band 11 and are connected to it only via certain sections of their edge.
When the small insertion plates 16 are inserted into the holes 15 of the support band 11, the further processing steps are facilitated by the small insertion plates 16 being fixed in their position in the holes 15 until they are finally bonded to the support band. Fixing can be achieved in an especially simple manner according to
After the small insertion plates 16 have been fixed in the holes 15 of the support band 11, the small insertion plates 16 and the support band 11 are bonded to one another at the edge of the small plates. In the case of small insertion plates 16 made of hardenable tool steel, a brazing method with following hardening process is preferred for this purpose according to
Instead of brazing, if the small insertion plates 16 are made of a weldable material, a welding method, in particular by means of laser beam or electron beam, may also be used as a bonding method (
Once the support band 11 and the small insertion plates 16 have been bonded to one another in this way, the support band 11 is separated according to
According to
Especially simple and elegant configurations of the method according to the invention are reproduced schematically in
In the configuration shown in
On the whole, the invention results in a method for the production of a bimetallic saw blade or saw band or circular saw blade which is distinguished by the following characteristic features and advantages:
Number | Date | Country | Kind |
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1073/04 | Jun 2004 | CH | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/CH05/00342 | 6/21/2005 | WO | 00 | 12/22/2006 |