Tip saw

Abstract

To provide a chip saw capable of obtaining a clean cut surface when cutting a hollow workpiece.SOLUTION: In a disc-like chip saw provided with a cutting edge piece 306 at a cutting edge part, the cutting edge piece 306 extends to a reverse rotation side of a chip saw, and has a cutting edge part on a rotation side of the chip saw provided with the cutting edge 306a and a support part on the reverse rotation side of the chip saw. The cutting edge piece 306 is configured to be wider and thicker than a base metal 31 of the chip saw ranging from the cutting edge part to a supporting part. The supporting part of the cutting edge piece 306 extends to a central position between one cutting edge 306a of at least two adjacent cutting edge pieces 306, 306 and the other cutting edge 306a. Thus, it is possible to narrow down a part where the base metal 31 is exposed from an outer periphery of the chip saw with comparison to a conventional chip saw and to reduce manufacturing costs of the chip saw.SELECTED DRAWING: Figure 27

Description

[Technical Field]

[0001] The present invention relates to a tip saw having cutting edges such as tips at the cutting edge of a circular saw. [Background technology]

[0002] Figure 29 is a plan view showing a state in which a pipe-shaped workpiece is cut using a conventional tipped saw. Figure 30 is an enlarged view of the area surrounded by the dashed line vii in Figure 29. As shown in Figures 29 and 30, cemented carbide alloys are harder than high-speed tool steel (high-speed steel, HSS) and do not lose much hardness at high temperatures, so they cut well when used in the cutting edge of a cutting tool. For this reason, in recent years, tipped saws 1 with cutting edge pieces 1a made of cemented carbide attached to the cutting edge have been widely used. In this type of tipped saw 1, the cutting edge pieces 1a are configured to be wider and thicker than the base metal 1A.

[0003] FIG. 31 is a plan view showing a conventional chip saw described in Patent Document 1. This FIG. 31 is the same as FIG. 1 of Patent Document 1. As shown in FIG. 31, Patent Document 1 describes a chip saw 2 (circular saw) for ripping wood. This chip saw 2 has a first cutting piece 2a (insert) and a second cutting piece 2b (insert, facing element, or insert). These first cutting piece 2a and second cutting piece 2b are made of cemented carbide. The first cutting piece 2a is attached to the cutting edge of the chip saw 2, and the second cutting piece 2b is attached to the edge of a groove 2s (slot) located between the cutting edge portions. This groove 2s extends radially inward, with one on each side of the rotation center O of the chip saw 2. Therefore, like the groove 2s, the second cutting piece 2b is provided on each side of the rotation center O of the chip saw 2.

[0004] FIG. 32 is a plan view showing a conventional tipped saw described in Patent Document 2. This FIG. 32 is the same as FIG. 5 of Patent Document 2. As shown in FIG. 32, Patent Document 2 describes a tipped saw 3 (circular saw) suitable for cutting wood and wood panels. This tipped saw 3 has a first cutting edge 3a (tip insert), a second cutting edge 3b (second wiper tip), and a third cutting edge 3c (first wiper tip). These first cutting edge 3a, second cutting edge 3b, and third cutting edge 3c are made of cemented carbide. The first cutting edge 3a is attached to the cutting edge portion. Three second cutting edges 3b are provided on the tipped saw 3, and are attached to the edges of grooves 3s (extended slits) between the cutting edge portions. The grooves 3s extend radially inward, and six grooves 3s are formed at predetermined angular intervals around the rotation center O. The second cutting edges 3b are provided around the rotation center O at every other groove 3s. Three third cutting edge pieces 3c are provided on the tip saw 3, and are attached to the edge of the elongated hole 3h (opening) of the base metal 3A (base disk). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 47-11320 [Patent Document 2] Patent No. 4754260 Summary of the Invention [Problem to be solved by the invention]

[0006] 29 and 30, when a conventional tipped saw 1 is used to cut a hollow (with an internal cavity) workpiece P, such as a pipe or column (rectangular tube), the cutting edge 1a is configured to be wider and thicker than the base metal 1A. Therefore, the cutting edge of the cutting edge piece 1a cuts the workpiece P to form a kerf Pc. When the cutting edge piece 1a is inserted into this kerf Pc, the width of the kerf Pc is maintained the same as the thickness of the cutting edge piece 1a. However, when the cutting edge piece 1a is not inserted into the kerf Pc, the width of the kerf Pc is maintained the same as the thickness of the base metal 1A, i.e., narrower than the thickness of the cutting edge piece 1a. For this reason, when cutting a hollow workpiece P, the width of the kerf Pc of the workpiece P fluctuates, sometimes increasing and sometimes decreasing, resulting in a problem of a dirty cut surface of the workpiece P.

[0007] If the number of cutting edges 1a in the chip saw 1 is increased to solve this problem, the distance between two adjacent cutting edges 1a, 1a will narrow, deteriorating the chip discharge performance of the chip saw 1. If the chip saws 2, 3 described in Patent Documents 1 and 2 shown in Figures 31 and 32 were improved to increase the number of second cutting edges 2b, 3b, the number of grooves 2s, 3s formed in the base metals 2A, 3A would increase, reducing the strength of the base metals 2A, 3A, and there is a risk that the chip saws 2, 3 will not be able to cut wood. For this reason, it is believed that such improvements are not anticipated in Patent Documents 1 and 2.

[0008] SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and its object is to provide a tip saw that can obtain a clean cut surface when cutting a hollow workpiece. [Means for solving the problem]

[0009] In order to solve the above problems, the chip saw of the present invention is a disc-shaped chip saw with a cutting edge at the cutting edge portion, a support piece is arranged between two adjacent cutting edges, the cutting edges and the support piece are configured to be wider and thicker than the thickness of the base metal of the chip saw, and the support piece has a thickness that is the same as or nearly the same as the thickness of the cutting edges.

[0010] According to this invention, a disc-shaped chip saw has cutting edges at the cutting edge portion, and a support piece is arranged between two adjacent cutting edges, and the cutting edges and the support piece are configured to be wider and thicker than the thickness of the base metal of the chip saw, and the support piece has a thickness that is the same as or nearly the same as the thickness of the cutting edges.As a result, the support piece has a thickness that is the same as or nearly the same as the thickness of the cutting edges and is arranged between two adjacent cutting edges, and therefore the support piece can maintain the width of the cutting groove formed by the cutting edges in the workpiece at a thickness that is the same as or nearly the same as the thickness of the cutting edges without increasing the number of cutting edges in the chip saw.

[0011] In the present invention, the support piece is preferably arranged so as to include at least the central position between the two adjacent cutting edge pieces or a position nearby there. According to this invention, by arranging the support piece so as to include at least the central position between the two adjacent cutting edge pieces or a position nearby there, it is possible to reduce variation in the distance between the adjacent cutting edge pieces and the support piece compared to a case where the support piece is biased toward one of the two adjacent cutting edge pieces and a part of the support piece is not arranged at the central position or a position nearby therebetween.

[0012] Here, the phrase "the support piece is arranged so as to include at least the central position or a position nearby therebetween" includes the following cases: when the support piece is arranged in the central position between the two adjacent cutting edges; when the entire support piece is biased toward one of the two adjacent cutting edges, and a part of the support piece is arranged in the central position or a position nearby therebetween; when a part of the support piece overlaps one of the two adjacent cutting edges in the circumferential direction, and the other part of the support piece is arranged in the central position or a position nearby therebetween; when the support piece extends so as to bridge the two adjacent cutting edges. In this case, both ends of the support piece may overlap both of the two adjacent cutting edges in the circumferential direction.

[0013] In the present invention, it is preferable that the support piece extends so as to overlap in the circumferential direction with the adjacent cutting edge piece on the reverse rotation side of the chip saw. According to this invention, since the support piece extends so as to overlap in the circumferential direction with the adjacent cutting edge piece on the reverse rotation side of the chip saw, the support piece and the adjacent cutting edge piece on the reverse rotation side of the chip saw are arranged adjacent to each other when viewed from the outer periphery of the chip saw, so that the portion that is wider and thicker than the base metal of the chip saw can be continuous without any gaps from the support piece to the adjacent cutting edge piece on the reverse rotation side of the chip saw.

[0014] In the present invention, the support piece is preferably attached to the outside of the base metal. According to this invention, by attaching the support piece to the outside of the base metal, the strength of the base metal is not reduced and the tipped saw can be manufactured easily and at low cost compared to when the support piece is provided on the inside of the base metal.

[0015] Here, the "outside of the base metal" refers to the area outside the outer periphery of the base metal. The teeth and recesses provided on the outer periphery of the chip saw are part of the base metal. Therefore, the "outside of the base metal" includes the outside of the teeth and the outside of the recesses.

[0016] In the present invention, the support piece is preferably provided on the inside of the base metal. According to this invention, since the support piece is provided on the inside of the base metal, the recess of the chip saw is not narrowed compared to when the support piece is attached to the outside of the base metal, and therefore deterioration of chip discharge performance of the chip saw can be prevented.

[0017] Here, the "inside of the base metal" refers to the area radially inward from the outer periphery of the base metal. The teeth and recesses provided on the outer periphery of the chip saw are part of the base metal. Therefore, the "inside of the base metal" includes the inside of the teeth and the inside of the recesses.

[0018] In the present invention, the cutting edge piece and the support piece are preferably made of different materials. According to this invention, since the cutting edge piece and the support piece are made of different materials, the material cost of the support piece can be reduced compared to the material cost of the cutting edge piece, thereby reducing the manufacturing cost of the tipped saw.

[0019] The chip saw of the present invention is a disc-shaped chip saw having a cutting edge piece at the cutting edge portion, the cutting edge piece extending toward the reverse rotation side of the chip saw, and having a cutting edge portion on the rotating side of the chip saw having a cutting edge and a support portion on the reverse rotation side of the chip saw, and the cutting edge piece is configured to be wider and thicker than the base metal of the chip saw from the cutting edge portion to the support portion.

[0020] According to this invention, a disc-shaped chip saw is provided with a cutting edge piece at the cutting edge portion, the cutting edge piece extending toward the reverse rotation side of the chip saw and having a cutting edge portion on the rotating side of the chip saw with a cutting edge and a support portion on the reverse rotation side of the chip saw, and the cutting edge piece is configured to be wider and thicker than the base metal of the chip saw from the cutting edge portion to the support portion.As a result, when cutting a workpiece with the chip saw, the cutting edge portion and the support portion of the cutting edge piece are inserted sequentially and continuously without any gaps into the cutting groove formed in the workpiece by the cutting edge piece, and therefore the width of the cutting groove in the workpiece can be maintained wider and thicker than the base metal of the chip saw for a longer period of time than when the support piece is positioned between two adjacent cutting edge pieces.

[0021] In the present invention, it is preferable that the support portion of the cutting edge piece extends to at least a central position between one cutting edge and the other cutting edge of two adjacent cutting edge pieces. According to this invention, by extending the support portion of the cutting edge piece to at least a central position between one cutting edge and the other cutting edge of two adjacent cutting edge pieces, the width of the kerf of the workpiece can be maintained for a longer period of time compared to when the support portion of the cutting edge piece does not reach the central position.

[0022] In the present invention, it is preferable that two adjacent cutting edges partially overlap in the circumferential direction. According to this invention, by partially overlapping two adjacent cutting edges in the circumferential direction, the two adjacent cutting edges are disposed adjacent to each other when viewed from the outer periphery of the tipped saw, and the cutting edges surround the base metal of the tipped saw circumferentially with no gaps. Therefore, when cutting a workpiece, the cutting edges can be continuously inserted without gaps into the kerf formed in the workpiece, and the width of the kerf can be constantly maintained.

[0023] In the present invention, it is preferable that the cutting edge portion and the support portion of the cutting edge piece are made of different materials. According to this invention, since the cutting edge portion and the support portion of the cutting edge piece are made of different materials, the material cost of the support portion can be reduced compared to the material cost of the cutting edge portion, thereby reducing the manufacturing cost of the tipped saw. [Effects of the Invention]

[0024] As described above, according to the present invention, a disc-shaped chip saw has cutting edges at the cutting edge portion, and a support piece is arranged between two adjacent cutting edges, or the cutting edges have a support portion extending toward the reverse rotation side of the chip saw.Therefore, when cutting a workpiece with the chip saw, the support piece or support portion can be inserted into the cutting groove formed in the workpiece by the cutting edges, thereby achieving the excellent effect of maintaining the width of the cutting groove in the workpiece. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a plan view showing a tip saw according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view showing the area surrounded by the dashed dotted line i in FIG. [Figure 3] 3 is a schematic end view showing the state as seen from the arrow L1 in FIG. 2. FIG. [Figure 4] 1 is a schematic plan view showing a state in which a hollow workpiece is cut by the tip saw of the first embodiment. FIG. [Figure 5] 5 is an enlarged view showing the area surrounded by the dashed line ii in FIG. 4. [Figure 6] FIG. 10 is a plan view showing the tip saw of the second embodiment. [Figure 7] 7 is an enlarged view showing the area surrounded by the dashed line iii in FIG. 6. [Figure 8] 8 is a schematic end view showing the state as seen from the arrow L2 in FIG. 7. FIG. [Figure 9] 10 is a schematic plan view showing a state in which a hollow workpiece is cut by the tip saw of the second embodiment. FIG. [Figure 10] 10 is an enlarged view showing the area surrounded by the dashed line iv in FIG. 9. [Figure 11] FIG. 10 is a plan view showing the tip saw of the third embodiment. [Figure 12] 12 is an enlarged view showing the area surrounded by the dashed line v in FIG. 11. [Figure 13] 13 is a schematic end view showing the state as seen from the arrow L3 in FIG. 12. FIG. [Figure 14] FIG. 10 is a schematic plan view showing a state in which a hollow workpiece is cut by the tip saw of the third embodiment. [Figure 15] 15 is an enlarged view showing the area surrounded by the dashed dotted line vi in FIG. 14. [Figure 16] FIG. 10 is an enlarged view showing the outer periphery of another tip saw according to the first embodiment. [Figure 17] FIG. 10 is an enlarged view showing the outer periphery of another tip saw according to the first embodiment. [Figure 18] FIG. 10 is an enlarged view showing the outer periphery of another tip saw according to the second embodiment. [Figure 19] FIG. 10 is an enlarged view showing the outer periphery of still another tip saw according to the second embodiment. [Figure 20] FIG. 10 is an enlarged view showing the outer periphery of another tip saw according to the second embodiment. [Figure 21] FIG. 10 is an enlarged view showing the outer periphery of yet another tip saw according to the second embodiment. [Figure 22] FIG. 10 is an enlarged view showing the outer periphery of another tip saw according to the third embodiment. [Figure 23] FIG. 11 is an enlarged view showing the outer periphery of still another tip saw according to the third embodiment. [Figure 24] FIG. 10 is an enlarged view showing the outer periphery of another tip saw according to the third embodiment. [Figure 25] FIG. 11 is an enlarged view showing the outer periphery of yet another tip saw according to the third embodiment. [Figure 26] FIG. 10 is an enlarged view showing the outer periphery of a different tip saw according to the third embodiment. [Figure 27] FIG. 11 is an enlarged view showing the outer periphery of yet another tip saw according to the third embodiment. [Figure 28] FIG. 10 is an enlarged view showing the outer periphery of a different tip saw according to the third embodiment. [Figure 29] FIG. 10 is a plan view showing a state in which a hollow workpiece is cut by a conventional tip saw. [Figure 30] FIG. 30 is an enlarged view showing the area surrounded by the dashed dotted line vii in FIG. 29. [Figure 31] FIG. 1 is a plan view showing the tip saw described in Patent Document 1. [Figure 32] FIG. 1 is a plan view showing the tip saw described in Patent Document 2. DETAILED DESCRIPTION OF THE INVENTION

[0026] (First embodiment) The tip saw of the first embodiment according to the present invention will be described in detail below. Fig. 1 is a plan view of the tip saw of the first embodiment according to the present invention. As shown in Fig. 1, the tip saw 10 is a disc-shaped circular saw, and has a base metal 11, a cutting piece 12, and a support piece 13.

[0027] In the figures, the direction indicated by the arrow Rt is the rotation side of the chip saw (the side that rotates counterclockwise around the center of rotation O in Figures 1, 4, 6, 9, 11, and 14, the left side of the page in Figures 2, 3, 7, 12, 13, and 16 to 28, and the upper left side of the page in Figures 5, 10, and 15). The direction indicated by the arrow Rv is the reverse rotation side of the chip saw (the side that rotates clockwise around the center of rotation O in Figures 1, 4, 6, 9, 11, and 14, the right side of the page in Figures 2, 3, 7, 12, 13, and 16 to 28, and the lower right side of the page in Figures 5, 10, and 15). The direction indicated by the arrow Ot is the radially outer side of the chip saw (the side away from the center of rotation O in Figures 1, 4, 6, 9, 11, and 14, the upper side of the paper in Figures 2, 7, 12, and 16 to 28, the front side of the paper in Figures 3, 8, and 13, and the upper right side of the paper in Figures 5, 10, and 15). The direction indicated by the arrow In is the radially inner side of the chip saw (the side closer to the center of rotation O in Figures 1, 4, 6, 9, 11, and 14, the lower side of the paper in Figures 2, 7, 12, and 16 to 28, the back side of the paper in Figures 3, 8, and 13, and the lower left side of the paper in Figures 5, 10, and 15). The direction indicated by arrow Fr is the front side of the chip saw (the front side of the paper in Figures 1, 2, 4 to 7, 9 to 12, 14 to 28, and the bottom side of the paper in Figures 3, 8, and 13). The direction indicated by arrow Bk is the rear side of the chip saw (the rear side of the paper in Figures 1, 2, 4 to 7, 9 to 12, 14 to 28, and the top side of the paper in Figures 3, 8, and 13). The directions indicated by arrows Rt and Rv are the circumferential direction of the chip saw. The directions indicated by arrows Ot and In are the radial direction of the chip saw. The directions indicated by arrows Fr and Bk are the thickness direction of the chip saw. These directions indicate relative positional relationships, and do not indicate absolute positional relationships with respect to the direction of gravity.

[0028] The base metal 11 is disk-shaped, and has teeth 14 and recesses 15 integrally formed on its outer periphery. The teeth 14 are approximately rectangular and protrude radially outward of the chip saw 10, as indicated by arrow Ot. The recesses 15 are concave and recessed radially inward of the chip saw 10, as indicated by arrow In. The inner bottom of the recesses 15 is curved in an arc. The teeth 14 and recesses 15 are alternately arranged one by one in the circumferential direction of the chip saw 10, as indicated by arrows Rt and Rv. In other words, the teeth 14 and recesses 15 are alternately arranged one by one around the center of rotation O. In the illustrated example, the teeth 14 and recesses 15 are part of the base metal 11. There are 60 teeth 14 and 60 recesses 15. The teeth 14 are arranged at an angle of 6° around the center of rotation O.

[0029] An attachment hole 11a is formed in the center of the base metal 11. This attachment hole 11a is an opening for connecting to a device (not shown) that rotates the chip saw 10, and penetrates the front and back plate surfaces of the base metal 11. In other words, the attachment hole 11a of the base metal 11 penetrates from the front surface 11A to the back surface 11B. The shape of this attachment hole 11a is not particularly limited, and in the illustrated example, it is formed in a circular shape when viewed from the front surface 11A. The rotation center O of the chip saw 10 is located at the center position of the attachment hole 11a. In other words, the chip saw 10 is configured to be rotatable around the rotation center O.

[0030] FIG. 2 is an enlarged view of the area enclosed by the dashed line i in FIG. 1. As shown in FIG. 2, the cutting piece 12 is a small, approximately rectangular piece (chip) made of a cutting tool material. This material may be, for example, cemented carbide, sintered diamond (Poly Crystalline Diamond, PCD), sintered CBN (Cubic Boron Nitride), cermet (a composite material of ceramics and metal), or Cermetal (a material intermediate between ceramics and cemented carbide). A cutting edge 12a is formed at the corner of the cutting piece 12 where the rotating side of the chip saw, indicated by arrow Rt, intersects with the radially outer side. This cutting edge 12a extends in the thickness direction from the front surface 12A to the back surface 12B of the cutting piece 12 (see FIG. 3). The cutting edge 12a enables the cutting piece 12 to cut a workpiece.

[0031] Next, like the cutting pieces 12, the support pieces 13 are small, roughly rectangular pieces (chips) made of a wear-resistant material, such as cemented carbide. The support pieces 13 may be made of the same material as the cutting pieces 12, or may be made of a different material than the cutting pieces 12. If the support pieces 13 are made of a different material than the cutting pieces 12, the material cost of the support pieces 13 can be made lower than the material cost of the cutting pieces 12, thereby reducing the manufacturing cost of the tip saw 10.

[0032] Here, a typical cemented carbide is made by mixing and sintering tungsten carbide (WC) with cobalt (Co) as a binder, and titanium carbide (TiC) or tantalum carbide (TaC) may be added as needed.

[0033] The cutting pieces 12 are attached to the rotation side of the chip saw 10 indicated by the arrow Rt of the tooth portion 14, and the support pieces 13 are attached to the reverse rotation side of the chip saw 10 indicated by the arrow Rv of the tooth portion 14. Therefore, the cutting pieces 12 and the support pieces 13 are arranged so as to sandwich the tooth portion 14 from both the rotation side and the reverse rotation side of the chip saw 10. As a result, the cutting pieces 12 and the support pieces 13 are arranged alternately, one by one, at a predetermined angle around the rotation center O of the chip saw 10. In the illustrated example, there are 60 cutting pieces 12 and 60 support pieces 13, the same as the tooth portions 14. The method of attaching these cutting pieces 12 and support pieces 13 is not particularly limited and may be, for example, brazing, soldering, welding, etc.

[0034] FIG. 3 is a schematic end view showing the state as viewed from the arrow L1 in FIG. 2. As shown in FIG. 3, the cutting pieces 12 are configured to be wider and thicker than the base metal 11. The thickness direction of the cutting pieces 12 is the thickness direction of the chip saw 10, indicated by arrows Fr and Bk. The surface 12A of the cutting pieces 12 protrudes from the surface 11A of the base metal 11 toward the surface side of the chip saw 10, indicated by arrow Fr, and the back surface 12B of the cutting pieces 12 protrudes from the back surface 11B of the base metal 11 toward the back surface side of the chip saw 10, indicated by arrow Bk. If the thickness of the cutting pieces 12 is D2 and the thickness of the base metal 11 is D1, the thickness D2 of the cutting pieces 12 is greater than the thickness D1 of the base metal 11 (D2 > D1). The thickness D2 of the cutting pieces 12 is the distance from the surface 12A to the back surface 12B in the thickness direction, and the thickness D1 of the base metal 11 is the distance from the surface 11A to the back surface 11B in the thickness direction. As a result, the cutting edge piece 12 is configured to be able to cut a workpiece wider than the thickness D1 of the base metal 11. The tooth portion 14 and the recessed portion 15 are both part of the base metal 11 and have a thickness that is the same as or nearly the same as the thickness D1 of the base metal 11.

[0035] Similarly, support piece 13 is configured to be wider and thicker than base metal 11. Surface 13A of support piece 13 protrudes from surface 11A of base metal 11 toward the surface side of the chip saw, and back surface 13B of support piece 13 protrudes from back surface 11B of base metal 11 toward the back surface side of the chip saw. If the thickness of support piece 13 is D3 and the thickness of base metal 11 is D1, thickness D3 of support piece 13 is greater than the thickness of base metal 11 (D3 > D1). Thickness D3 of support piece 13 is the distance from surface 13A to back surface 13B in the thickness direction.

[0036] Furthermore, the support piece 13 has the same or nearly the same thickness as the cutting piece 12. The surface 13A of the support piece 13 is disposed in the thickness direction at the same position as or nearly the same as the surface 12A of the cutting piece 12, and the back surface 13B of the support piece 13 is disposed in the thickness direction at the same position as or nearly the same as the back surface 12B of the cutting piece 12. In other words, the thickness D3 of the support piece 13 is the same or nearly the same as the thickness D2 of the cutting piece 12 (D3 = D2 or D3 ≈ D2).

[0037] 2 and 3, the support piece 13 is disposed between two circumferentially adjacent cutting pieces 12, 12. The base metal 11 is exposed from the outer periphery of the chip saw 10 between the cutting piece 12 and the adjacent support piece 13 on the rotation side of the chip saw 10, and between the cutting piece 12 and the adjacent support piece 13 on the reverse rotation side. Therefore, when viewing the chip saw 10 from the outer periphery, the thickness in the thickness direction of the chip saw 10 is smaller than the thickness of the cutting piece 12 and the support piece 13 in the portion between the cutting piece 12 and the adjacent support piece 13 on the rotation side of the chip saw 10 and the portion between the cutting piece 12 and the adjacent support piece 13 on the reverse rotation side of the chip saw 10. In other words, the distance extending from the cutting edge piece 12 in the circumferential direction toward the rotating side of the chip saw 10 when the base metal 11 has thickness D1 is from the cutting edge piece 12 to the adjacent support piece 13 on the rotating side of the chip saw 10, and the distance extending from the cutting edge piece 12 in the circumferential direction toward the reverse rotation side of the chip saw 10 when the base metal 11 has thickness D1 is from the cutting edge piece 12 to the adjacent support piece 13 on the reverse rotation side of the chip saw 10.

[0038] Here, let the distance from the cutting blade piece 12 to the support piece 13 adjacent to the rotating side of the chip saw 10 be W1a, the distance from the cutting blade piece 12 to the support piece 13 adjacent to the reverse rotating side of the chip saw 10 be W1b, and the distance between two adjacent cutting blade pieces 12, 12 be W1. Then, both the distance W1a and the distance W1b are shorter than the distance W1, and the sum of the distance W1a and the distance W1b is shorter than the distance W1 by the length in the circumferential direction of the support piece 13 of the chip saw 10 (W1a < W1, W1b < W1, W1a + W1b < W1). In this case, the distance W1a is the distance that extends in the circumferential direction from the cutting blade piece 12 to the rotating side of the chip saw 10 in the state of the thickness D1 of the base 11, and the distance W1b is the distance that extends in the circumferential direction from the cutting blade piece 12 to the reverse rotating side of the chip saw 10 in the state of the thickness D1 of the base 11.

[0039] Also, the support pieces 13 are respectively arranged so as to include at least the central position or a position near the central position between two adjacent cutting blade pieces 12, 12. This includes the case where the support piece 13 is located at the center between two adjacent cutting blade pieces 12, 12, and the case where the whole support piece 13 is offset to one of two adjacent cutting blade pieces 12, 12 and a part of the support piece 13 is located at the center between two adjacent cutting blade pieces 12, 12. In this case, both the distance W1a and the distance W1b are smaller than half of the distance W1 (W1a < 1 / 2·W1, W1b < 1 / 2·W1), and the variation between the distance W1a and the distance W1b is reduced. In other words, when looking at the chip saw 10 from the outer periphery, the portion where the base 11 is exposed becomes smaller in the circumferential direction of the chip saw 10.

[0040] FIG. 4 is a schematic plan view showing a state in which a hollow workpiece is cut using the tipped saw of the first embodiment. FIG. 5 is an enlarged view of the area surrounded by the dashed line ii in FIG. 3. As shown in FIGS. 4 and 5, when a hollow workpiece P is cut using the tipped saw 10, the cutting edge 12 cuts into the workpiece P to form a kerf Pc. When the cutting edge 12 is inserted into the kerf Pc, the width of the kerf Pc is maintained equal to the thickness D2 of the cutting edge 12. When the support piece 13 is inserted into the kerf Pc, the width of the kerf Pc is maintained equal to the thickness D3 of the support piece 13. When only the base metal 11 is inserted into the kerf Pc in the workpiece P, the width of the kerf Pc is maintained equal to the thickness D1 of the base metal 11. At this time, the thickness D3 of the support piece 13 is larger than the thickness D1 of the base metal 11 (D3>D1) and is the same as or nearly the same as the thickness D2 of the cutting edge piece 12 (D3=D2 or D3≒D2). As a result, when the support piece 13 is inserted into the kerf Pc of the workpiece P, the width of the kerf Pc is larger than the thickness D1 of the base metal 11 and is maintained at a width that is the same as or nearly the same as the thickness D2 of the cutting edge piece 12.

[0041] When the chip saw 10 configured as described above is rotated around the rotation center O toward the rotation side of the chip saw 10 to cut into the hollow workpiece P, the cutting edge 12a of the cutting edge piece 12 cuts the workpiece P to form a cutting groove Pc, and the cutting edge piece 12, a portion of the base metal 11, and a portion of the support piece 13 and the base metal 11 are inserted in sequence into this cutting groove Pc to cut the workpiece P.

[0042] In the first embodiment, the support piece 13 is arranged between two adjacent cutting pieces 12, 12, and the thickness D3 of the support piece 13 is greater than the thickness of the base metal 11 and is the same as or nearly the same as the thickness D2 of the cutting piece 12.Therefore, when the chip saw 10 is rotated to cut into the hollow workpiece P, the cutting edge 12a of the cutting piece 12 forms a cutting groove Pc in the workpiece P, and then the cutting piece 12 and the support piece 13 are inserted alternately and continuously into this cutting groove Pc one by one, and the workpiece P is cut while maintaining the width of the cutting groove Pc to be the same as or nearly the same as the thickness D2 of the cutting piece 12.Therefore, the cut surface of the hollow workpiece P can be formed more cleanly than with a chip saw that does not have a support piece 13.

[0043] In this first embodiment, the distance extending circumferentially from the cutting blade piece 12 toward the rotating side of the chip saw 10 in the state of the thickness D1 of the base 11 is the distance W1a between the cutting blade piece 12 and the adjacent support piece 13 on the rotating side of the chip saw 10, and the distance extending circumferentially from the cutting blade piece 12 toward the reverse-rotating side of the chip saw 10 in the state of the thickness D1 of the base 11 is the distance W1b between the cutting blade piece 12 and the adjacent support piece 13 on the reverse-rotating side of the chip saw 10. Since these distances W1a and W1b are shorter than the distance W1 between two adjacent cutting blade pieces 12, 12 (W1a < W1, W1b < W1), when the support piece 13 is not provided, that is, when the distances extending circumferentially from the cutting blade piece 12 toward the rotating side and the reverse-rotating side of the chip saw 10 in the state of the thickness D1 of the base 11 are both the distance W1, the distances extending circumferentially from the cutting blade piece 12 toward the rotating side and the reverse-rotating side of the chip saw 10 in the state of the thickness D1 of the base 11 become shorter respectively. Therefore, when cutting the workpiece P with the chip saw 10, the width length of the cutting groove Pc of the workpiece P can be held wider by the support piece 13.

[0044] Further, since the support piece 13 is arranged so as to include at least the central position or a position near the central position between two adjacent cutting blade pieces 12, 12, both the distance W1a from the cutting blade piece 12 to the adjacent support piece 13 on the rotating side of the chip saw 10 and the distance W1b from the cutting blade piece 12 to the adjacent support piece 13 on the reverse-rotating side of the chip saw 10 are smaller than half of the distance W1 between two adjacent cutting blade pieces 12, 12 (W1a < 1 / 2·W1, W1b < 1 / 2·W1). When cutting the workpiece P with the chip saw 10, the variation in the timing of alternately inserting the cutting blade piece 12 and the support piece 13 one by one into the cutting groove Pc of the workpiece P can be reduced.

[0045] (Second Embodiment) FIG. 6 is a plan view of a tip saw blade according to a second embodiment. FIG. 7 is an enlarged view of the area enclosed by the dashed line iii in FIG. 6. As shown in FIGS. 6 and 7, the tip saw blade 10 of the first embodiment has the support piece 13 attached to the outside of the base metal 11, whereas the tip saw blade 20 of the second embodiment has the support piece 23 attached to the inside of the base metal 21. The inside of the base metal 21 refers to the area radially inward from the outer periphery of the base metal 21. Because the tooth portion 24 and the recessed portion 25 are part of the base metal 21, the inside of the base metal 21 includes the area radially inward from the outer periphery of the tooth portion 24 and the area radially inward from the outer periphery of the recessed portion 25. Note that the same parts as those of the tip saw blade 10 of the first embodiment are designated by the same reference numerals, and their description will be omitted. The cutting edge piece 12 of the second embodiment is the same as the cutting edge piece 12 of the first embodiment. The support piece 23 of the second embodiment is made of the same material as the support piece 13 of the first embodiment.

[0046] As shown in FIG. 7 , the inside of the base metal 21 refers to the radially inner side of the outer periphery of the base metal 21. Specifically, notches 21n are formed in the base metal 21. These notches 21n are disposed radially inward of the portions extending from the tooth portions 24 to the recessed portions 25. The notches 21n are oval or elliptical when viewed from the front surface 21A of the base metal 21 and penetrate from the front surface 21A to the back surface 21B of the base metal 21. The support pieces 23 are fitted into the notches 21n and have the same planar shape as the notches 21n. In other words, the support pieces 23 are oval or elliptical. Therefore, compared to when the support pieces 23 are attached to the outside of the tooth portions 24, the recessed portions 25 of the chip-discharge saw 20 are not narrowed, and deterioration of chip discharge performance can be prevented. Note that although the notches 21n are formed on the outer periphery of the base metal 21, they may be openings or through-holes provided radially inward from the outer periphery of the base metal 21.

[0047] FIG. 8 is a schematic end view showing the state as viewed from the arrow L2 in FIG. 7. As shown in FIGS. 7 and 8, the support piece 23 is disposed between two adjacent cutting edges 12, 12, in a position biased toward the cutting edge piece 12 on the reverse rotation side of the tipped saw 20. A portion of the support piece 23 is located in the center between the two adjacent cutting edges 12, 12, and another portion extends so as to overlap the cutting edge piece 12 on the reverse rotation side of the tipped saw 20 in the circumferential direction. In this case, the base metal 21, support piece 23, and cutting edge piece 12 of the second embodiment have the same thicknesses D1, D3, and D2 as the base metal 11, support piece 13, and cutting edge piece 12 of the first embodiment, respectively. Therefore, when viewed from the outer periphery of the tipped saw 20, the support piece 23 and the adjacent cutting edge piece 12 on the reverse rotation side are disposed adjacent to each other in the circumferential direction and are continuous with the same or nearly the same thickness. In other words, the surface 23A of the support piece 23 and the surface 12A of the adjacent cutting edge piece 12 on the reverse rotation side are continuous in the circumferential direction without any steps, and the back surface 23B of the support piece 23 and the back surface 12B of the adjacent cutting edge piece 12 on the reverse rotation side are continuous in the circumferential direction without any steps.

[0048] 8, when viewed from the outer periphery of the saw blade 20, a portion of the base metal 21 having thickness D1 extends from the cutting edge piece 12 toward the reverse rotation side of the saw blade 20, but does not extend from the cutting edge piece 12 toward the rotation side of the saw blade 20. The circumferential distance of this portion of the base metal 21 having thickness D1 is distance W2b from the cutting edge piece 12 to the adjacent support piece 23 on the reverse rotation side of the saw blade 20. In other words, of the distance W2 between two adjacent cutting edge pieces 12, 12, only distance W2b is the portion of the base metal 21 having thickness D1. Therefore, compared to the saw blade 10 of the first embodiment, the saw blade 20 can reduce the portion of the base metal 21 having thickness D1 exposed from the outer periphery of the saw blade 20.

[0049] Fig. 9 is a schematic plan view showing a state in which a hollow workpiece is cut by the tip saw of the second embodiment. Fig. 10 is an enlarged view showing the area surrounded by the dashed line iv in Fig. 9. As shown in Figs. 9 and 10, when the tip saw 20 cuts the hollow workpiece P, if the support piece 23 is inserted into the kerf Pc in the workpiece P formed by the cutting edge 12a of the cutting piece 12, the width of the kerf Pc is maintained at the same width as the thickness D3 of the support piece 23, i.e., the same width as or nearly the same as the thickness D2 of the cutting piece 12.

[0050] When the chip saw 20 configured as described above is rotated around the rotation center O toward the rotating side of the chip saw to cut into the hollow workpiece P, the cutting edge 12a of the cutting edge piece 12 cuts the workpiece P to form a cutting groove Pc, and the cutting edge piece 12, a portion of the base metal 21, and the support piece 23 are inserted in sequence into this cutting groove Pc to cut the workpiece P.

[0051] In the second embodiment, the support piece 23 is positioned inside the base metal 21, so that the support piece 23 does not narrow the recess 25 of the chip saw 20, compared to the chip saw 10 of the first embodiment in which the support piece 13 is attached to the outside of the tooth portion 14, thereby preventing a deterioration in the chip discharge performance of the chip saw 20.

[0052] In this second embodiment, the support piece 23 and the adjacent cutting edge piece 12 on the reverse rotation side of the chip saw 20 overlap circumferentially, and when viewed from the outer periphery of the chip saw 20, the support piece 23 and the adjacent cutting edge piece 12 on the reverse rotation side of the chip saw 20 are arranged adjacent to each other, so that the support piece 23 and the adjacent cutting edge piece 12 on the reverse rotation side of the chip saw 20 are continuous with the same thickness or nearly the same thickness, and therefore the width of the cutting groove Pc in the workpiece P can be maintained wider for a longer period of time than the chip saw 10 of the first embodiment.

[0053] (Third embodiment) FIG. 11 is a plan view showing a tip saw of the third embodiment. FIG. 12 is an enlarged view showing the area surrounded by the dashed line v in FIG. 11. As shown in FIGS. 11 and 12, the tip saw 10 of the first embodiment and the tip saw 20 of the second embodiment have support pieces 13, 23 between two adjacent cutting pieces 12, 12, but the tip saw 30 of the third embodiment does not have a support piece, and the cutting piece 32 extends toward the reverse rotation side of the tip saw 30. Note that the same parts as those of the tip saw 10 of the first embodiment are given the same reference numerals, and their description will be omitted. The cutting piece 32 of the third embodiment is made of the same material as the cutting piece 12 of the first embodiment.

[0054] The cutting edge piece 32 of the third embodiment has an elongated shape and is provided with a cutting edge 32a at the end on the rotation side of the tip saw 30. The cutting edge piece 32 is attached to the radially outer side of the tooth portion 34 and extends obliquely from the cutting edge 32a on the rotation side to the reverse rotation side of the tip saw 30 along the outer periphery of the tooth portion 34. In the illustrated example, the cutting edge piece 32 covers the entire outer periphery of the tooth portion 34. The method of attaching the cutting edge piece 32 to the tooth portion 34 is not particularly limited, and may be, for example, brazing, soldering, or welding.

[0055] As shown in Figure 12, the cutting edge piece 32 has a cutting edge portion 32x and a support portion 32y. The cutting edge portion 32x is the portion of the cutting edge piece 32 that faces the rotation side of the tipped saw 30 and includes the cutting edge 32a. The support portion 32y is the portion of the cutting edge piece 32 that faces the rotation side of the tipped saw 30 in the opposite direction. The cutting edge portion 32x and the support portion 32y have the same thickness D2. As a result, after the cutting edge piece 32 forms a kerf Pc in the workpiece P with the cutting edge 32a of the cutting edge portion 32x, the support portion 32y can maintain the width of the kerf Pc at the same thickness D2 of the cutting edge piece 32.

[0056] 13 is an end view showing the state as viewed from the arrow L3 in FIG. 12. As shown in FIGS. 12 and 13, a portion of each cutting edge piece 32 circumferentially overlaps with an adjacent cutting edge piece 32 on the reverse rotation side of the tipped saw 30. In other words, two adjacent cutting edge pieces 32, 32 partially overlap in the circumferential direction. Specifically, of two adjacent cutting edge pieces 32, 32, the support portion 32y of one cutting edge piece 32 circumferentially overlaps with the cutting edge portion 32x of the other cutting edge piece 32. In other words, the cutting edge pieces 32 are arranged at a predetermined angle around the rotation center O so that they partially overlap in the circumferential direction, and surround the base metal 31 without any gaps in the circumferential direction.

[0057] 13, when the tipped saw 30 is viewed from the outer periphery, two adjacent cutting pieces 32, 32 are adjacently arranged with no gaps in the circumferential direction, and are continuous from one cutting piece 32 to the other cutting piece 32 with the same thickness D2. In other words, of two adjacent cutting pieces 32, 32, the surface 32A of one cutting piece 32 is continuous with the surface 32A of the other cutting piece 32 with no steps in the circumferential direction, and the back surface 32B of one cutting piece 32 is continuous with the back surface 32B of the other cutting piece 32 with no steps in the circumferential direction. This allows the cutting pieces 32 to be inserted continuously into the kerf P of the workpiece P without any gaps.

[0058] Fig. 14 is a schematic plan view showing a state in which a hollow workpiece is cut by the tip saw of the third embodiment. Fig. 15 is an enlarged view showing the area surrounded by the dashed line vi in Fig. 14. As shown in Figs. 14 and 15, when the tip saw 30 cuts the hollow workpiece P, when the cutting piece 32 is inserted into the kerf Pc formed by the cutting edge 32a of the cutting piece 32, the width of the kerf Pc is maintained at the same width as the thickness D2 of the cutting piece 32.

[0059] When the chip saw 30 configured as described above is rotated around the rotation center O toward the rotation side and cuts into the hollow workpiece P, the cutting edges 32a of the cutting edge pieces 32 cut the workpiece P to form a cutting groove Pc, and the cutting edge pieces 32 are inserted continuously into this cutting groove Pc without leaving any gaps, thereby cutting the workpiece P.

[0060] In the third embodiment, the chip saw 30 does not have support pieces 13, 23, so the number of parts can be reduced and manufacturing costs can be reduced compared to the chip saws 10, 20 of the first and second embodiments, which have both cutting pieces 12 and support pieces 13, 23.

[0061] In this third embodiment, the cutting edge pieces 32 extend toward the reverse rotation side of the chip saw 30, and the cutting edge pieces 32 surround the base metal 31 in a circular pattern with no gaps, so that two adjacent cutting edge pieces 32, 32 overlap partially in the circumferential direction.As a result, when cutting a hollow workpiece P with the chip saw 30, the cutting edge pieces 32 are inserted continuously without any gaps into the cutting groove Pc in the workpiece P formed by the cutting edges 32a of the cutting edge pieces 32, so that the width of the cutting groove Pc can always be maintained at the same width as the thickness D2 of the cutting edge piece 32, and a cleaner cut surface can be obtained than with the chip saws 10 and 20 of the first and second embodiments.

[0062] The saw blades 10, 20, and 30 of the first to third embodiments are not limited to the illustrated examples described above, and various modifications can be made without departing from the spirit of the present invention. For example, while the support piece 13 of the first embodiment is rectangular with rounded corners (see FIG. 2), the support piece 101 may be rectangular with sharp corners (see FIG. 16), and the support piece 102 may be substantially triangular with a hypotenuse that extends linearly from the radially outer end (protruding end) of the tooth portion 14 to the inner bottom of the recess 15 (see FIG. 17).

[0063] Furthermore, in the second embodiment, the support piece 23 is disposed radially inside the portion extending from the tooth portion 24 to the recessed portion 25 (see FIG. 7), but it may be disposed radially inside the tooth portion 24 (at the base of the tooth portion 24) or may be disposed radially inside the recessed portion 25. The support pieces 201, 202, 203, and 204 may be disposed in portions of the tooth portion 24 on the reverse rotation side of the chip saw 20 (see FIGS. 18 to 21).

[0064] Although support piece 23 in the second embodiment is oval or elliptical (see FIG. 7), the planar shape of support piece 23 is not particularly limited and may be, for example, circular or polygonal, such as pentagonal, hexagonal, or octagonal. Also, support piece 201 may be rectangular (see FIG. 18), support piece 202 may be semicircular (see FIG. 19), support piece 203 may be semicircular (see FIG. 20), and support piece 204 may be crescent-shaped (see FIG. 21).

[0065] Furthermore, although the cutting edge piece 32 in the third embodiment is linear and extends obliquely from the rotation side to the reverse rotation side of the tip saw 30 (see FIG. 12), the cutting edge piece 301 may be curved (see FIG. 22).

[0066] In the third embodiment, the radially inner portion of the cutting piece 32, i.e., the portion that contacts the tooth portion 34, is flat (see FIG. 12), but the portions of the cutting pieces 302, 303, and 304 that contact the tooth portion 34 are preferably uneven (see FIGS. 23 to 25). This makes it difficult for the cutting pieces 302, 303, and 304 to come off the tooth portion 34. Specifically, the cutting piece 302 is formed with a protrusion 302p that protrudes in the extension direction of the cutting piece 302 and a recessed depression 302q (see FIG. 23). The cutting piece 303 is formed with a protrusion 303p that protrudes in a direction intersecting the extension direction of the cutting piece 303, i.e., in the direction that contacts the tooth portion 34, and a recessed depression 303q (see FIG. 24). The cutting edge piece 304 is formed with dovetail grooves 304q, 304q recessed in the direction of contact with the tooth portion 34 (see FIG. 25).

[0067] Furthermore, although the entire cutting piece 32 in the third embodiment is made of a single material, the cutting edge portion 32x on the rotation side of the tipped saw 30 and the support portion 32y on the reverse rotation side of the tipped saw 30 may be made of different materials. For example, as shown in Figure 26, the cutting edge portion 305x of the cutting piece 305 is made of the same cutting tool material as the cutting piece 12 of the first embodiment, and the support portion 305y is made of the same wear-resistant material as the support piece 13 of the first embodiment. This reduces the manufacturing cost of the tipped saw.

[0068] Furthermore, while in the third embodiment, two adjacent cutting edge pieces 32, 32 are arranged so as to partially overlap in the circumferential direction, two adjacent cutting edge pieces 306, 306 and 307, 307 may be arranged so as not to overlap in the circumferential direction (see FIGS. 27 and 28). For example, as shown in FIG. 27, when the distance from one cutting edge 306a to the other cutting edge 306a of two adjacent cutting edge pieces 306, 306 is W3, the cutting edge piece 306 may extend along the outer periphery of the tooth portion 34 to a position corresponding to at least half of the circumferential distance W3 (½ W3). This allows the portion of the base metal 31 exposed from the outer periphery of the chip saw to be narrower than in conventional chip saws, and also reduces the manufacturing cost of the chip saw.

[0069] 28, the cutting edge portion 307x of the cutting edge piece 307 on the rotation side of the tipped saw 30 and the support portion 307y on the reverse rotation side of the tipped saw 30 may be made of different materials. That is, the cutting edge portion 307x of the cutting edge piece 307 is made of the same cutting tool material as the cutting edge piece 12 of the first embodiment, and the support portion 307y of the cutting edge piece 307 is made of the same wear-resistant material as the support piece 13 of the first embodiment. This reduces the manufacturing cost of the tipped saw. [Explanation of symbols]

[0070] 1,2,3,10,20,30...Tipped saw, 1a,12,32,301,302,303,304,305,306,307...Cutting blade piece, 1A,3A, 11,21,31...Base metal, 2a,3a...First cutting blade piece, 2b,3b...Second cutting blade piece, 2s,3s...Groove , 3c...Third cutting blade piece, 3h...Long hole, 11a...Mounting hole, 11A, 12A, 13A, 21A, 23A, 32A...Surface, 11B, 12B, 13B, 21B, 23B, 32B...Back surface, 12a, 32a, 306a... Cutting edge, 13, 23, 101, 102, 201, 202, 203, 204...Support pieces, 14, 24, 34...Tooth portion, 15, 25...Concave portion, 21n...Notch, 302p, 303p...Convex portion, 302q, 303q...Dent, 304q...Dovetail groove, 32x, 305x, 307x...Cutting edge portion, 32y, 305y, 307y...Support portion, D1, D2, D3...Thickness, O...Center of rotation, P...Workpiece material, Pc...Knife groove, Rt, Rv, Ot, In, Fr, Bk, L1, L2, L3...Arrow, W1, W1a, W1b, W2, W2b, W3...Distance, i, ii, iii, iv, v, vi...Dash line

Claims

1. A disc-shaped tipped saw blade having a cutting edge piece at a cutting edge portion, the cutting edge piece extending toward the reverse rotation side of the tipped saw blade, having a cutting edge portion on the rotation side of the tipped saw blade having a cutting edge and a support portion on the reverse rotation side of the tipped saw blade, the cutting edge piece being configured to be wider and thicker than the base metal of the tipped saw blade from the cutting edge portion to the support portion, The support portion of the cutting edge piece extends to at least a central position between one cutting edge and the other cutting edge of two adjacent cutting edge pieces.

2. A disc-shaped tipped saw blade having a cutting edge piece at a cutting edge portion, the cutting edge piece extending toward the reverse rotation side of the tipped saw blade, having a cutting edge portion on the rotation side of the tipped saw blade having a cutting edge and a support portion on the reverse rotation side of the tipped saw blade, the cutting edge piece being configured to be wider and thicker than the base metal of the tipped saw blade from the cutting edge portion to the support portion, The two adjacent cutting edge pieces partially overlap in the circumferential direction.

3. 3. The tip saw according to claim 1, wherein the cutting edge portion and the support portion of the cutting edge piece are made of different materials, and the support portion is made of a wear-resistant material.

4. The tip saw according to claim 3, wherein the cutting edge portion of the cutting piece is made of cemented carbide.

5. 4. The tip saw according to claim 3, wherein the support portion of the cutting edge piece is made of cemented carbide.

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