SJOEDAHL FREDRIK (SE)
NILSSON TOBIAS (SE)
SJOEDAHL FREDRIK (SE)
| WO1984001316A1 | 1984-04-12 |
| EP0718414A1 | 1996-06-26 | |||
| US4849602A | 1989-07-18 | |||
| US20050050801A1 | 2005-03-10 |
| 1. | Segment (11) for a saw blade, cutting blade or drill, said segment comprises a number of diamonds bounded in a metal matrix that surrounds the diamonds, characterized in that the cutting surface on the segment (11) is a fracture surface (13) and that the concentration of diamonds in the segment close to the fracture surface is higher than in the section opposite the fracture surface. |
| 2. | Segment (11) according to claim 1, characterized in that the metal matrix normally is a mixture of Iron, Copper or Cobalt. |
| 3. | Segment (11) according to claim 1 or 2, characterized in that the width of the cutting surface is smaller than the maximum width of the segment. |
| 4. | Segment (11) according to claim 1,2 or 3, characterized in that the segment (11) is joined to a metal core and curved to match the shape of the metal core. |
| 5. | Segment (11) according to any of the previous claims, characterized in that the segment (11) is provided with a flat side (15) opposite the fracture surface (13) to ensure maximum strength in the joint between the segment (11) and a metal core. |
| 6. | Method for producing a segment (11) according to claim 1 for a saw blade, cutting blade or drill, said method includes the step; Mixing a number of diamonds with metal powder or powders, Fill a mould with the diamond and metal powder mixture, Press the diamond and metal powder mixture in the mould to a first shape including a pair (10) or a set of segments, Heating the pair (10) or set of segments to a predetermined temperature so that the metal powder is transformed into a solid matrix surrounding and bounding the diamonds in the matrix and forming the pair (10) or set of segments in the final shape, Breaking the pair (10) or set of segments into single segments (11) and using the fracture surface (13) as the cutting surface for the segment (11). |
| 7. | Method according to claim 6, further comprising the step of providing the pair (10) of segments (11,12) with one or two recesses (14) to facilitate breaking the pair (10) or set of segments in the predetermined area. |
| 8. | Method according to claim 6 or 7, further comprising the step of distributing the diamond metal powder mixture in such a way that the concentration of diamonds in higher in the section of the segment close to the fraction surface than in the side opposite the fraction surface. |
Saw blades and drills provided with a number of abrasive cutting segments used in combination with for example wall or floor saws, power cutters and drilling machines are frequently used for different kind of work within the construction area. The saw blades and drills are used for cutting or drilling in for example concrete, asphalt or stone-type materials.
A saw blade comprises a circular metal core with a plurality of segments affixed to the periphery of the circular core by welding or soldering. The segments on a saw blade extend in radial direction from a disc shaped metal core while a drill is made of a cylinder shaped metal core attached to the drive shaft in one end provided with segments in the other end.
The segments are affixed side by side on the edge of the cylinder shaped metal core in such a way that they extend from the edge in axial direction of the cylinder.
In order to make the cutting efficient and fast the segments must be strong and resistant to wear. This is achieved by making segments containing a number of diamonds that are very hard and resistant to wear.
The segments are manufactured by mixing the diamonds with metal powder. The powder and diamond mixture is pressed in a mould into a first simple shape or a shape close to the desired final shape of the segment and heated to a specific temperature for a predetermined period of time so that the powder is turned into a solid segment, a matrix, that surrounds the diamonds and bounds them in the segment. The segment is during the heating also shaped in the desired final shape of the segment. This method for manufacturing is normally called sintering and each segment is manufactured one by one.
Almost all metals could be used in different combinations for creating a matrix with desired features but the metal powder is normally a mixture of Iron, Copper or Cobalt powder. The different metal powders are mixed in order to optimize the features of the segment for the specific material that the saw blade or drill will be used for. The amounts of each of the different components in the diamond and metal powder mixture, as well as the temperature that the segment is heated to during the manufacturing process, is also selected so that the features of the segment will be as good as possible for the specific use of the saw blade or drill. The matrix is mainly used for bounding the diamonds in the segment while the diamonds are used for cutting.
The metal matrix, as already described, surrounds the diamonds in the segment and bounds the diamonds in the segment. The fact that the matrix surrounds the diamonds is however a drawback since very few diamonds will be exposed on the cutting surface on the segment when the saw blade or tool is new. This problem is solved by grinding the cutting surface of the segments so that the matrix on the cutting surface of the segment is removed and more diamonds exposed on the cutting surface of the segment.
The amount of diamonds in the section of the segment close to the flat surface that is welded or soldered to the metal core is lower than in the cutting part of the segment. This ensures maximum strength in the joint between the segment and the metal core and a higher concentration of diamonds in the cutting part of the segment.
Manufacturing of segments are complicated, time consuming and consequently also expensive since the manufacturing includes several different steps.
The claimed segment and manufacturing method reduces this problem by making the manufacturing less complicated and eliminating the final step where the segments are grinded before use of a new saw blade, cutting blade or drill. This is done by manufacturing the segments in pairs or a set of segments. After the pair or set of segments are sintered and the diamond and metal powder mixture turned into a solid matrix are the segments separated by breaking the pair or rack of segments into segments and using the fraction surface on the segment as the cutting surface.
One embodiment of the claimed invention is illustrated in the drawings.
Figure 1. Illustrates a perspective view of a pair of segments for a drill.
Figure 2. Illustrates a cross section of the pair of segments in figure 1.
Figure 3. Illustrates a perspective view of a segment for a drill.
Figure 4. Illustrates a cross section for the segment in figure 3.
In figure 1 is a perspective view of a pair 10 of cutting segments according to the claimed invention illustrated. The pair 10 of segments includes a first 11 and a second 12 segment manufactured according to the claimed method.
The pair 10 of segments is manufactured by mixing predetermined amounts of different metal powders with a number of diamonds or diamond powder. The diamond and metal powder is pressed in a mould to first simple shape or a shape close to the desired final shape of the pair 10 of segments. The pair 10 of segments is heated to a predetermined temperature so that the metal powder mixture is transformed into a solid matrix surrounding and bounding the diamonds in the matrix. During the heating process is the pair of segments formed in the desired final shape of the segment. The final step in the manufacturing process is breaking the pair 10 of segments into two separated segments.
Each segment 10 and 11 will then have a fraction surface 13 that will be used as the cutting surface for the segment 11.
The pair 10 of segments is provided with two recesses 14, one on each side of the pair 10 of segments. These recesses make it easier to break the pair 10 of segments into separate peaces. The illustrated embodiment of the invention is provided with recesses 14 on both sides. It is however not necessary to use recesses 14 at all.
The shape of the segment is designed to match the blade or drill that the segments will be used for. The segments 11 and 12 illustrated in the drawings are used for a drill and therefore curved sideways so that the curvature of the segments 11 and 12 will be the same as the one on the cylindrical metal core that the segments are welded or soldered to.
Opposite the fracture surface 13 on the segment is a flat surface 15. The surface 15 is flat to facilitate welding or soldering of the segment to the metal core.
The section of the segment close to the flat surface 15 is normally manufactured without diamonds to ensure maximum strength in the joint between the segment and the metal core and reduce the amounts of diamonds in the tool where they not are required. The length, width and height of the segments are selected for the specific use of the saw blade, cutting blade or drill.
Segments for a saw blade or cutting blade are either not curved or curved in the radial direction of the blade. This embodiment is not illustrated in the drawings.
Segments are either placed separated from each other to allow for water and waste material to be transferred away from the cutting area, or packed together side by side around the disk or cylinder shaped metal core which is favorable in some cases.
The illustrated segment 11 is provided with a grove 16 on the curved side facing outwards in radial direction. This grove 16 is used to reduce the friction between the segment 11 on the drill and the hole during use of he drill.