CIRCULAR SAW BLADE
Patent Information
- Application Number
- BR112022016655
- Authority / Receiving Office
- BR · BR
- Patent Type
- Patents
- Current Assignee / Owner
- Publication Date
- 2026-09-08
Smart Images
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Abstract
Description
1 / 11 Descriptive Report of the Invention Patent for a CIRCULAR SAW BLADE. Field of Invention
[001] The present invention relates to circular saw blades, more particularly, for example, to improved cutting tips for a circular saw blade, configured to cut a moving electrical resistance welded pipe. Background of the Invention
[002] Electrically resistance welded tubes have been widely used, and are generally formed from a long sheet of metal in a width direction in order to form a tubular shape. A seam (joint) is formed in a longitudinal direction, and is electrically welded to form a hollow tubular body. To electrically weld a seam of an electrically resistance welded tube, means such as high-frequency electrical resistance welding, or frequency induction heating welding, can be adopted. Since these welding means do not require any welding materials, such as a welding rod or welding wire, the beads, which form weld marks, and the tubular body are formed of substantially the same material. Consequently, there is almost no difference in hardness between these two. A streak of a weld bead remains as a weld mark on the seam of an electrically resistance welded tube.
[003] Electrically resistance welded tubes can be continuously and consistently produced in a factory, from the formation of a metal sheet within a hollow tubular body, until the tubular body is cut to a specific length. That is, a flat metal sheet (e.g., steel strip), which is to subsequently become a tubular body, is continuously spread in a longitudinal direction. The flat metal sheet is then rolled in a direction of Petition 870240064808, dated 07 / 31 / 2024, p. 7 / 37 2 / 11 width, and fed as a long tubular body, having a predetermined diameter (roll formation). Since there is a seam (joint) to be formed in the longitudinal direction of the rolled tubular body, the seam is formed by electrically welding on an upstream side of a production process. This welding is done in synchronicity with the distribution of the tubular body.
[004] As a result, a long electrical resistance welded tube is produced, the tube having a seam integrated by a weld bead. In a downstream portion of the process, after the tube has passed through the welding process, the weld bead still remains in the seam of the electrical resistance welded tube. This occurs even though a projecting portion of the weld bead remained on an outer circumferential surface, and on an inner circumferential surface of the electrical resistance welded tube it is trimmed by a grinder. The continuously distributed electrical resistance welded tube is cut into a tubular body, having a desired length by a circular saw cutting machine, running in synchronicity with the electrical resistance welded tube, as the tube runs downstream.
[005] As the present invention relates to an improvement for cutting tips for a circular saw blade, the cutting tips of a conventional circular saw blade will be briefly described. FIG. 9(a) is an enlarged side view of a cutting tip 10, for a circular saw blade used for a roller-type circular blade cutting machine. FIG. 9(b) is a front view illustrating a tilting face, located on a front of the cutting tip 10 shown in FIG. 9(a) in a direction of rotation. FIG. 9(c) is a plan view of a flank 18 of the cutting tip 10, the flank 18 being located in an outer circumferential direction of the circular saw blade. More specifically, each of the cutting tips 10 Petition 870240064808, dated 07 / 31 / 2024, page 8 / 37 3 / 11 welded onto an outer circumference of a common metal 12 includes a first tilting face 14, a flank 18, and a second tilting face 22. The first tilting face 14 is located in front of the circular saw blade, in a direction of rotation. The flank 18 defines a first cutting edge 16, on a line of intersection between the flank 18 and the first tilting face 14. The second tilting face 22 is located in front of the circular saw blade in a direction of rotation, and is adjacent to the first tilting face 14 on one side of an axis of the circular saw blade. The reference number 23 in FIG. 9 represents a release groove. The release groove 23 can be used to separate cutting chips generated while cutting a workpiece. List of Citations Patent Literature Patent Literature 1: JP6339764B Patent Literature 2: JPH08-309609A Summary of the Invention Technical Problem
[006] FIG. 10 is a cross-sectional view illustrating a situation in which a resistance-welded tube 24 is being cut by a traveling-type circular saw cutting machine. As described above, the weld bead on the resistance-welded tube 24 is trimmed by a grinder. To this end, as shown in FIG. 10(a), the trimmed weld bead 26 is dispersed and remains on the tube. As shown in FIG. 10(b), the second inclined face 22 of a subsequent cutting tip 10 then bites the weld bead 26 remaining inside the bottom of the tube, between an inner wall of the tube and a cutting tip 10, as the circular saw blade continues to rotate. At this moment, a significant impact and / or load is concentrated on the second inclined face 22 of the cutting tip 10. Petition 870240064808, dated 07 / 31 / 2024, page 9 / 37 4 / 11 which tends to cause excessive wear and chipping of the second bevel face 22. For example, for the cutting tip 10 illustrated in the perspective view of FIG. 11, spots near the joints with the common metal 12, and both sides of the second bevel face 22, may be stress concentration points due to the cutting tip 10 biting the weld bead 26. In this way, these stress concentration points may be points where wear or chipping are more likely to occur. Since a hollow tubular body made of tensile steel, which as a material has a tensile strength (e.g., exceeding 1000N / mm2), even if it is not a resistance-welded tube, cutting the tips of a conventional circular saw blade may not cut well into the tubular body. Solution to the Problem
[007] In order to solve the problem and achieve the desired objective, the present invention according to claim 1 is to provide a circular saw blade having a plurality of cutting edges joined together on an outer circumference of a common metal. Each of the cutting edges includes a first tilting face, a flank, and a second tilting face. The first tilting face is located on a first front of the circular saw blade, in a direction of rotation. The flank is configured to define a first cutting edge, on a line of intersection with a first tilting face, and is located on an outer circumference of the circular saw blade. The second tilting face is located on a front of the circular saw blade in the direction of rotation, and is adjacent to the first tilting face on one side of the axis of the circular saw blade.The center of the second tilting face projects forward in the direction of rotation of the circular saw blade. According to the invention of claim 1, since the second tilting face of the cutting tip projects forward in the direction of rotation of... Petition 870240064808, dated 07 / 31 / 2024, p. 10 / 37 5 / 11 circular saw blade, the impact stress received during the cutting of a workpiece, such as a welded resistance pipe, can be concentrated in the center of the second bevel face. Additionally, this impact stress is unlikely to spread to either side of the second bevel face. This can reduce the risk of chiseling the cutting edges and the risk of the edges detaching from the base metal. In this way, the average lifespan of the circular saw blade can be extended.
[008] According to the invention defined in claim 2, the second inclination face is configured to define a second cutting edge, on a line of intersection with the flank. According to the invention of claim 2, the corners of the flank, side edges, and the second inclination face of the cutting tip become less prone to chipping. This is, in part, due to an angle defined by the side edge and the second cutting edge being increased, due to the chamfered angles of the face of the second cutting edges, on both sides of the cutting tip. Advantageous Effects of the Invention
[009] According to the circular saw blade of the present invention, since the center of a second inclined face 22 of a cutting tip 10 is configured to project forward in the direction of rotation of a circular saw blade, an impact stress would not be concentrated on the ends of the second inclined face 22, even if a significant impact force occurs, such as a weld bead 26 being punctured during the cutting of a workpiece. This can reduce the risk of damage to the cutting tips, and of breakage and / or lack of a joint between the cutting tip 10 and the common metal 12. In this way, the service life of the circular saw blade can be extended. Petition 870240064808, dated 07 / 31 / 2024, page 11 / 37 6 / 11 Brief Description of the Drawings
[0010] FIG. 1(a) is a plan view of a cutting edge, according to an exemplary embodiment of the present invention. FIG. 1(b) is a front view, showing a second inclined face of the edge. FIG. 1(c) is a side view of an entire circular saw blade.
[0011] FIG. 2 is an enlarged view of a flank, of the cutting edge shown in FIG. 1(a). FIG. 2 illustrates the first inclination face, which is formed in a triangular shape.
[0012] FIG. 3 is an enlarged view of the first tilt face and the second tilt face, of the cutting edge shown in FIG. 1(b). FIG. 3 illustrates the first tilt face, which is in the center and is formed in a triangular shape.
[0013] FIG. 4 is a perspective view of a cutting edge, according to an exemplary embodiment, illustrating a projection of the second inclination face, inclined to the right and to the left, with a plane section interposed in the center.
[0014] FIG. 5(a) is a plan view of the cutting tip, according to the second exemplary embodiment of the present invention. FIG. 5(b) is a front view of the second inclination face of the tip.
[0015] FIG. 6(a) is a plan view of a cutting edge, according to a third exemplary embodiment of the present invention. FIG. 6(b) is a front view of the second inclination face of the edge.
[0016] FIG. 7(a) is a plan view of a cutting edge, according to a fourth exemplary embodiment of the present invention. FIG. 7(b) is a front view of the second inclination face of the edge.
[0017] FIGS. 8(a) to 8(d) illustrate the first polygonal face of the inclinations formed on the cutting edge, according to exemplary embodiments. FIG. 8(a) is a first triangular inclination face. Petition 870240064808, dated 07 / 31 / 2024, p. 12 / 37 7 / 11 (fan-shaped). FIG. 8(b) is a first face with a rectangular slope. FIG. 8(c) is a first face with a pentagonal slope. FIG. 8(d) is a first face with a hexagonal slope.
[0018] FIG. 9(a) is an enlarged side view of a cutting edge, for a circular saw blade. FIG. 9(b) is a front view, illustrating a tilting face of the cutting edge. FIG. 9(c) is a plan view of a flank of the cutting edge.
[0019] FIGS. 10(a) and 10(b) are cross-sectional views illustrating phases during the cutting of an electric resistance welding tube with a migrating type circular saw cutting machine. FIG. 10(a) illustrates a state in which a bead remains at the bottom and inside the tube. FIG. 10(b) illustrates a state in which the bead has been chipped into a second angled face of the cutting tip, while the bead is held against an inner wall of the tube.
[0020] FIG. 11 is a perspective view of the cutting edge shown in FIG. 9, in which the points on either side of the second inclination face serve as stress concentration points due to the bead bite. Description of Modalities
[0021] Hereafter, exemplary embodiments of cutting tips, attached to a circular saw blade, according to the present invention, will be described with reference to the drawings. The electrically resistance welded tube described above is considered to be an object to be cut (workpiece) with the circular saw blade, according to the exemplary embodiments. However, another workpiece made of a different material, such as, for example, high-tensile steel, may also be considered to be an object to be cut.
[0022] First, FIG. 1(a) is a plan view of a cutting edge. 10, according to an exemplary embodiment. The cutting tip 10 is connected to a circular saw blade, as shown in FIG. 1(c). A Petition 870240064808, dated 07 / 31 / 2024, p. 13 / 37 8 / 11 FIG. 1(b) is a front view, illustrating a second tilting face 22 of the tip 10. As shown in FIGS. 1(a) and (b), the second tilting face 22 of the cutting tip 10 of the exemplary embodiment defines the second cutting edges 52, on both sides of an intersection line with a flank 18. As also shown in FIGS. 1(a) and 1(b), the second tilting face 22 of the cutting tip includes a projection 30 formed by enabling the center of the second tilting face 22 to project slightly forward, in the direction of rotation of the circular saw blade. The projection 30 is formed as if projecting from the center of the second tilting face 22, such that the second tilting face 22, in a state inclined to the left and to the right, as illustrated in FIG. 2. Figure 2 shows a first side of the enlarged slope face of flank 18. The chamfer angles α of the right and left faces shown in FIG. 2 vary from 2° to 50°.A first inclination angle ranges from -30° to 0°, and a second inclination angle from -5° to 10°. Furthermore, when the first inclination angle is chamfered between flank 18 and a side edge, as shown in FIGS. 1(a) and (b), a crest line between the chamfered face and an inclination face defines a cutting edge. If this inclination face is the second inclination face 22, the cutting edge forms a part of the second cutting edge 52.
[0023] Several experiments were conducted on the chamfer angles α of the face, inclined to the right and to the left on the second face of inclination 22, to find the appropriate ranges for the angles. More specifically, the chamfer angles α of the face were changed to 0°, 2°, 7°, 30° and 50°, and an electrical resistance welded tube was cut. When the electrical resistance welded tube was cut, an impact and other stresses applied to the second face of inclination 22 of the cutting tip were analyzed step by step. During these tests, a stress concentration scar was generated. Petition 870240064808, dated 07 / 31 / 2024, page 14 / 37 9 / 11 in projection 30, at a location shown in FIG. 1(b), due to impacts. This was observed every time the stress was analyzed. It was found that the damaged tip or chip was unlikely to occur, since the stress concentration scar appears in the vicinity of the center of projection 30 of the second tilt face 22. This was observed in all analyses.
[0024] Considering the results of the analyses, the change in stress applied to the second face of inclination 22, when the cutting tips begin to cut while in contact with the workpiece (the weld bead), and the cutting through the workpiece was found to be well balanced and favorable, if the bevel angles α of the face when measured in the vicinity of the projection center 30, fall within the range of equal to or greater than 7° and less than 30°. Compared to the cases where the bevel angles α of the face are 0° and 2°, an area of a stress concentration point during the cutting of the workpiece was smaller in the case of 2°. It was also found that the risk of chipping should increase, since an intense stress concentration occurs immediately after contacting the workpiece, if the bevel angles α of the face exceed 30°.However, even when the chamfer angles α of the face are 2° or 50°, it has been confirmed that the beneficial effect is sufficiently significant when compared with conventional cutting tips with a second flat inclination face 22.
[0025] As shown in FIG. 1(b), the projection 30 formed on the second inclined face 22 of the cutting tip 10 of FIG. 1, is formed as a line at the intersection between two faces inclined to their respective sides. However, as exemplary alternative embodiments, as shown in FIG. 4 to FIG. 7, the projection 30 may be formed not as a line between the right and left inclined faces, but formed to have a planar section or a rounded section, Petition 870240064808, dated 07 / 31 / 2024, page 15 / 37 10 / 11 interlaced between the inclined faces. For example, FIG. 4 is a perspective view of a cutting edge 10, as an exemplary embodiment. In this exemplary embodiment, the projection 30 of the second inclined face 22 projects vertically forward in the direction of rotation of the circular saw blade, and projects into the center of the second inclined face 22. In other words, the projection 30 inclines to the right and to the left with the flat section 22a interlaced in the center of the second inclined face 22.
[0026] Furthermore, projection 30 of FIG. 5 is rounded, while projection 30 of FIG. 6 is flat. Moreover, projection 30 of FIG. 7 is flat and chamfered. Chipping of the edge may be more likely to occur when the edge cuts the weld bead 26 if the width in the thickness direction of the edge of a flat surface of projection 30 exceeds 1 mm. However, it has been found that the circular saw blade is able to cut well even when there is a weld bead 26 if the width of the flat surface of projection 30 is equal to or narrower than 1 mm.
[0027] In the present invention, since the center of the second tilting face 22 of the cutting tip 10 is left to extend in the direction of rotation of the circular saw blade, the flank 18 of the cutting tip 10 is divided into a plurality of sections in the direction of the rotating axis of the circular saw blade. This results in the first tilting face 14 of the cutting tip 10 forming a polygonal shape in the vicinity of the center, as shown in FIG. 3. FIGS. 8 (a) to (d) illustrate the first tilting face 14, which has such a polygonal shape. More specifically, in FIG. 8 (a), the first tilting face 14 is formed in a triangular shape (fan shape), and in FIG. 8 (b), the first tilting face 14 is formed in a rectangular shape. In FIG. 8 (c), the first tilting face 14 is formed in a pentagonal shape, while in FIG. 8 (d), the first face of Petition 870240064808, dated 07 / 31 / 2024, page 16 / 37 11 / 11 inclination 14, is formed in a hexagonal shape. List of Reference Signs: cutting edge, 12 common metal, 14 first inclination face, 16 first cutting edge, 18 flank, 22 second inclination face, α face chamfer angle, 52 second cutting edge Petition 870240064808, dated 07 / 31 / 2024, page 17 / 37
Claims
1 / 2 CLAIMS 1. Circular saw blade, characterized in that it has a plurality of cutting points (10) joined together on an outer circumference of a common metal (12), each of the cutting points (10) comprising: a first inclination face (14) located on a front of the cutting point, in a direction of rotation of the circular saw blade; a flank (18) configured to define a first cutting edge (16), on a line of intersection with the first inclination face (14), the flank being located on an outer circumference of the circular saw blade;and a second tilting face (22) located in front of the cutting edge, in the direction of rotation of the circular saw blade, the second tilting face being adjacent to the first tilting face (14), on one side of an axis of the circular saw blade, wherein a center of the second tilting face (22) is configured to project forward, in the direction of rotation of the circular saw blade, wherein the second tilting face (22) defines a second cutting edge (52) on a line of intersection with the flank (18), and wherein the flank (18) is divided into sections on a rotational axis of the circular saw blade by a release groove (23) extending from a portion between the first cutting edge (16) and the second cutting edge (52).
2. Circular saw blade, according to claim 1, characterized in that the second tilting face (22) is inclined from the center of the second tilting face to the right, and from the center of the second tilting face to the left, in such a manner that the second tilting face is formed to project, and wherein the face bevel angles (α) of the second tilting face vary from 2° to 50°.