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(11) | EP 1 270 161 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Circular saw blade having a support disc with holes of different sizes |
| (57) A circular saw blade (1) has a pattern of holes (5) in its body and cutting elements
(3) around its periphery. The presence of the holes (5) enhances the properties of
the circular saw blade, examples of which are improved heat dissipation and reduced
weight. Holes of various sizes are arranged on the saw in such a way so as to provide
the associated benefits in certain regions of the saw whilst maintaining structural
strength in other regions of the saw, as it is required. |
Field of Invention
[0001] The present invention relates generally to circular saw blades, and more particularly to circular saw blades with holes in their side faces.
Background of the Invention
[0002] When a cutting operation is performed using a circular saw equipped with a standard circular saw that has no holes in its side faces, a work-piece is cut by the abrasive tips as the blade is rotated. During this operation, a large amount of heat is generated on not only the annular cutting region, but also both side faces of the disk, so that the side faces are rapidly heated. The heat generated in the disk is transmitted to the abrasive tips, so that the durability thereof is reduced, the cut surfaces of the work-piece become rough, and the work-piece is not cut precisely. Additionally, the heat can cause the disc to become deformed, and this can lead to the generation of noise, and even to jamming of the blade in the cut slot in the work-piece or disintegration of the blade; all of which can have safety implications.
[0003] It is well known that by making a circular saw with holes in its side faces the above problems can be reduced by the increased airflow through the holes in the saw. Another benefit of this kind of circular saw is the improved dust removal from the cutting site by the holes. Also, for every hole made in the saw blade the weight is reduced, this lowered weight makes the saw easier to handle. The presence of a large number of irregularly spaced holes makes it possible to see the work piece being cut. However, a balance must be set between having enough holes to maximise the benefits, and maintaining the structural integrity and safety of the saw blade.
[0004] One way in which the number of holes in the saw blade has been increased without adversely affecting the strength of the saw blade is to provide a pattern of holes arranged in a spiral design which results in the formation of spiral spokes. These spiral spokes provide a stronger support than straight spokes formed between the same number of holes.
Statement of Invention
[0005] Accordingly, this invention provides a circular saw blade comprising a support disc, with a pattern of holes in the body thereof, having cutting elements disposed around the periphery thereof, characterised in that the pattern of holes comprises a plurality of holes of different sizes.
[0006] In a preferred embodiment the cutting disc may have a central pivot region, which does not penetrate the cut in the work-piece, thus permitting it to be thicker than the rest of the disc. It will be appreciated by the man skilled in the art that the increased thickness at the centre of the cutting disc will provide increased strength against side loading during cutting.
[0007] It may be preferable for the different sized holes to be arranged in rings running concentric to the central pivot of the circular saw. Each ring could be made up of a collection of holes of substantially equal sizes.
[0008] The larger sized holes could be located closer to the cutting elements than the smaller sized holes. With this arrangement the larger holes near the cutting elements provide an improved level of heat dissipation, while the smaller holes nearer the centre of the saw blade provide a lower, but still noticeable, level of heat dissipation whilst retaining the structural integrity of the saw blade.
[0009] Alternatively, the smaller sized holes could be located closer to the cutting elements than the larger sized holes. With this arrangement the smaller holes near the cutting elements satisfy a need for strength at the rim, whilst the larger holes near the centre of the saw blade facilitate improved removal of dust, or water passage nearer the centre of the saw blade. It is appreciated that alternative arrangements of rings may provide useful benefits.
[0010] Preferably, the rings could be arranged so that a hole in one ring is not directly in line with a hole in an adjacent ring. By adopting this arrangement the transfer of heat through the metal, from the cutting edge to the central region of the saw, can be impeded by forcing the heat to be conducted along a more convoluted path and thus allowing more time for the heat to be dissipated.
[0011] It may be advantageous for the thickened central pivot region to also have holes, thereby increasing the appreciated benefits further.
[0012] In a preferred embodiment the holes are substantially circular in shape, although it will be appreciated that other shaped holes may provide a desirable effect.
[0013] It will be understood that all the other benefits, as discussed earlier, of holes in the cutting disc will also be provided by the invention. These include amongst other things, vibration reduction and noise reduction.
[0014] It will also be understood from the invention that different types of cutting elements may be used on these cutting discs. Typical examples being wood cutting elements and diamond tipped blades.
Brief Description of the Drawings
[0015] In the drawings, which illustrate preferred embodiments of the invention:
Figure 1 is a diagrammatic view of a circular cutting blade;
Figure 2 is an enlarged view of Section A in Figure 1 for a preferred embodiment, which is suitable for cutting wood;
Figure 3 is an enlarged view of Section A in Figure 1 for another preferred embodiment, which is suitable for cutting wood;
Figure 4 is an enlarged view of Section A in Figure 1 for a preferred embodiment, which is suitable for cutting stone;
Figure 5 is an enlarged view of Section A in Figure 1 for another preferred embodiment, which is suitable for cutting stone;
Figure 6 is a cross-sectional view illustrating an embodiment of the invention wherein the central pivot region has an increased thickness for increased strength;
Figure 7 is an enlarged view of Section A in Figure 1 with an alternative arrangement of rings.
Figures 8-11 are diagrammatic representations of Section A in Figure 1 showing alternative patterns of hole size arrangement.
Detailed Description of the Illustrated Embodiments
[0016] Figure 1 shows a standard circular cutting disc 1 comprising a main body 2, with cutting elements 3 arranged around its periphery, and a central mounting hole 4 which is engaged by the disc driving means (not shown). Also a sectional portion A has been highlighted by a dashed line.
[0017] Figure 2 shows a representative sectional portion A1 of a preferred embodiment of the invention which is suitable for cutting wood. This portion shows the arrangement of holes, which would be continued around the whole of the cutting disc. In this arrangement the holes 5 are grouped in to rings that run concentric to the central mounting hole 4. Each ring is made up of a plurality of equal sized holes. The rings are arranged so that the smallest holes 5a are nearest the central mounting hole 4 and the largest holes 5c are furthest away from the central mounting hole 4.
[0018] Figure 3 shows another preferred embodiment where once again the cutting disc has equal sized holes arranged into concentric rings. However in this embodiment the ring comprising the largest holes 5c is arranged closest to the central mounting hole 4 and the ring comprising the smallest holes 5a is furthest from the central hole. As in Figure 2 this embodiment has cutting elements 3a suited to cutting wood.
[0019] Figures 4 and 5 show similar arrangement to Figures 2 and 3 but with cutting elements 3b more suitable for stone cutting.
[0020] In the embodiments illustrated in Figures 2-5, between the inner ring holes and outer ring of holes, there may be a varied number of rings each comprising equal sized holes of different gradations.
[0021] Figure 6 shows an embodiment of the invention in which the central pivot region 6 is thicker than the rest of the cutting disc. The thicker region provides increased strength to the central region of the disc. The diameter of the thicker region is dependant on the required cutting depth of the disc. It will be appreciated from the invention that a balance between the thicker central pivot region and the outer cutting region must be achieved so that the disc has strength but still retains enough holes to give the necessary benefits.
[0022] Figure 7 shows an alternative arrangement of the relationship between adjacent rings of holes. The rings are arranged so that a hole in one ring is out of line with a neighbouring hole in the adjacent rings. This arrangement acts to impede the transfer of heat from the cutting edge to the centre of the cutting disc, by providing a more tortuous path of metal through which the heat must travel before it reaches the centre of the disc.
[0023] Figures 8-11 show a variety of alternative arrangements. In each arrangement the pattern of hole sizes is different. For example in Figure 8, starting from the outer edge of the cutting disc there is a ring of large holes followed by a ring of smaller holes, then another ring of large holes and finally another ring of smaller holes.
1. A circular saw blade (1) comprising a support disc (2), with a pattern of holes in
the body thereof, having cutting elements disposed (3) around the periphery thereof,
characterised in that the pattern of holes comprises a plurality of holes of different sizes (5).
2. A circular saw blade according to Claim 1, wherein the pattern of holes comprises
the different sized holes arranged in concentric rings, wherein each ring is made
up of a collection of similar sized holes.
3. A circular saw blade according to Claim 1 or 2, wherein the larger sized holes (5c)
are located closer to the cutting elements (3) than the smaller holes (5a).
4. A circular saw blade according to Claim 1 or 2, wherein the smaller sized holes (5a)
are located closer to the cutting elements (3) than the larger holes (5c).
5. A circular saw blade according to any preceding claim, wherein holes in one ring
are arranged out of line with holes in an adjacent ring.
5. A circular saw blade according to any preceding claim comprising a central pivot
region (6) of greater thickness than the rest of the blade.
6. A circular saw blade according to Claim 5, wherein the central pivot region (6) also
has holes located in it.
7. A circular saw blade according to any preceding claim, wherein the holes (5) are
substantially circular in shape.
8. A circular saw blade according to any preceding claim, wherein the cutting elements
are stone cutting blades (3b).
9. A circular saw blade according to any preceding claim, wherein the cutting elements
are diamond tipped.