WEAR-RESISTANT CUTTING TOOL

Abstract

Cutting tool (10) for use in acting on earth strata, the cutting tool (10) being a non-rotatable type tool and comprising: a cutting tool body (12) having a central longitudinal axis (AA), an axial front end (14), an axial rear end (16), a head portion (18) adjacent to the axial front end (14), and a shank portion (20) adjacent to the axial rear end (16), the head portion (18) comprising: a partially frustoconical portion (22) having a first side edge (24) and a second side edge (26); a first side surface (28) having a first lateral transition edge (30) and a first end edge (32), the first lateral transition edge (30) being adjacent to the first side edge (24) of the partially frustoconical portion (22); and a second side surface (34) having a second lateral transition edge (36) and a second end edge (38), the second lateral transition edge (36) being adjacent to the second side edge (26) of the partially frustoconical portion (22) and the first end edge (32) being adjacent to the second end edge (38) to form a cutting edge (40); and a hard cutting tip (42) attached to the axial front end (14) of the cutting tool body (12); wherein the head portion (18) is not rotationally symmetrical with respect to the central longitudinal axis (AA).

Description

[0001] The invention generally relates to a wear-resistant cutting tool suitable for impacting a substrate or earth strata such as asphalt pavement material, coal deposits, mineral formations and the like.

[0002] A cutting tool typically has a generally elongated, cylindrical geometry. The cutting tool includes an elongated steel cutting tool body having an axial leading end and an opposite axial trailing end. A hard cutting element is typically attached to the axial leading end of the cutting tool body. The cutting tool body typically carries an arrangement or means by which the cutting tool is rotatable and is supported by a stationary block or holder on a drum. Alternatively, the cutting tool may be non-rotatable, i.e., fixed in place, within the block or holder on a drum.

[0003] During operation, such as in a road grading or mining application, the holder or block supporting the cutting tool is driven forward to impact the earth strata, fracturing or crushing the earth strata. As can be seen, strong forces are exerted on the cutting tools, and in particular on the cutting tool bodies and hard cutting elements. Consequently, it is important that the cutting tool body and hard cutting elements possess optimal properties suitable for withstanding such a harsh operating environment for an acceptable duration.

[0004] Cutting tools are known from WO 2009 / 003 233 A1, US 3 833 264 A, DE 12 33 355 A and DE 101 33 948 A1.

[0005] Consequently, it is recognized that cutting tools can experience wear in a number of ways due to the environment in which they operate and require frequent replacement. Consequently, it would be highly desirable to create an improved cutting tool that offers an extension of tool life compared to previously known cutting tools.

[0006] According to one aspect of the invention, a cutting tool for use in impacting earth strata comprises a cutting tool body having a central longitudinal axis, an axial leading end, an axial trailing end, a head portion adjacent the axial leading end, and a shank portion adjacent the axial trailing end. The head portion includes a partially frustoconical portion having a first side edge and a second side edge. The head portion also includes a first side surface having a first lateral transition edge and a first end edge, the first lateral transition edge being adjacent to the first side edge of the partially frustoconical portion.The head portion further includes a second side surface having a second lateral transition edge and a second end edge, the second lateral transition edge being adjacent to the second lateral edge of the partially frustoconical portion, and the first end edge being adjacent to the second end edge to form a cutting edge. The cutting tool also includes a hard cutting tip secured to the axial leading end of the cutting tool body. Here, the cutting tool is a non-rotatable type tool in which the head portion is not rotationally symmetrical with respect to the central longitudinal axis.

[0007] These and other aspects of the present invention will be more fully understood after a review of this specification and the drawings. Fig. 1 is an isometric view of a cutting tool according to one aspect of the invention. Fig. 2 is a front view of the Fig. 1 according to one aspect of the invention. Fig. 3 is a side view of the Fig. 1-2 according to one aspect of the invention. Fig. 4 is a bottom view of the Fig. 1-3 according to one aspect of the invention.

[0008] With reference to Fig. 1-4, a cutting tool, generally designated by the reference numeral 10, is illustrated in accordance with aspects of the invention. It will be appreciated that the invention has application to various types of cutting tools useful in various types of cutting operations. Example operations include road grading (or milling), coal mining, concrete cutting, and other types of cutting operations in which a cutting tool having a hard cutting element impacts a substrate (e.g., soil strata, pavement, asphalt road material, concrete, and the like), breaking the substrate into pieces of a variety of sizes, including larger-sized pieces or chunks and smaller-sized pieces, including dust-like particles.It will also be appreciated that the cutting tool 10 of the invention can be manufactured in various sizes and dimensions depending on the desired application of the tool.

[0009] The cutting tool 10 has a central longitudinal axis AA. The cutting tool 10 includes an elongated cutting tool body, generally designated 12, which is typically made of steel, for example. The elongated cutting tool body 12 has an axial forward end 14 and an axial rearward end 16.

[0010] The elongated cutting tool body 12 includes a head portion 18 adjacent the axial forward end 14 and a shank portion 20 adjacent the axial rearward end 16. The shank portion 20 can be provided with various shapes and configurations. In one aspect, the shank portion 20 is structured and arranged to be non-rotatable, such that the cutting tool 10 is a non-rotatable type tool. The shank portion 20 can be inserted, for example, into a bore of a tool holder in which a retaining ring or other suitable means can be provided to axially retain the cutting tool and restrict free rotation (not shown). In another aspect, the shank portion 20 can be, for example, rectangular or square, as represented by reference numeral 21 (see dashed lines in Fig. 1), and inserted into a similarly configured or shaped bore of a tool holder to prevent rotation of the cutting tool 10.

[0011] According to aspects of the invention, the head portion 18 is structured and arranged to include a partially frustoconical portion 22 having a first side edge 24 and an opposite second side edge 26. In one aspect, the partially frustoconical portion 22 is continuous from the first side edge 24 to the second side edge 26.

[0012] According to another aspect of the invention, the head portion 18 is structured and arranged to also include a first side surface 28 having a first lateral transition edge 30 and an opposite first end edge 32. The first lateral transition edge 30 is structured and arranged to be adjacent, contiguous, or connected to the first side edge 24 of the partially frusto-conical portion 22. The head portion 18 also includes a second side surface 34 having a second lateral transition edge 36 and an opposite second end edge 38. The second lateral transition edge 36 is structured and arranged to be adjacent, contiguous, or connected to the second side edge 26 of the partially frusto-conical portion 22.

[0013] The head portion 18 is further structured and arranged such that the first end edge 32 is adjacent to, contiguous with, or connected to the second end edge 38 to form a cutting edge 40.

[0014] In one aspect, at least a portion of the first side surface 28 and the second side surface 34 is generally planar or flat. In another aspect, at least a portion of the first side surface 28 and / or the second side surface 34 may be coated with a wear-resistant material, generally represented by 29 and 35, respectively (see Fig. 2). A suitable wear-resistant material may be, for example, KenCast®, which is a commercially available product from Kennametal Inc. of Latrobe, PA, the assignee of the present application.

[0015] Advantageously, the described configuration of the head portion 18 improves the overall strength, durability, wear resistance, and / or cutting performance of the cutting tool 10. Furthermore, the invention advantageously provides a wedge effect to assist in severing the substrate and yielding larger particles, thus reducing the small parts generated during the cutting process.

[0016] According to another aspect of the invention, the cutting tool 10 further includes a hard cutting tip, generally designated by the reference numeral 42, adjacent the axial front end 14. The hard cutting tip 42 may be secured, for example, by brazing the hard cutting tip 42 to the head portion 18 adjacent the axial front end 14 of the cutting tool body 12.

[0017] In one aspect, the hard cutting tip 42 is structured and arranged to contact a substrate 44 (see Fig. 1), which may be made of a hard material, such as tungsten carbide (cobalt tungsten carbide). The hard cutting tip 42 further comprises a layer of a superhard material 46 bonded to the substrate 44 (see Fig. 1). The layer of superhard material 46 may comprise, for example, polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PCBN).

[0018] The layer of superhard material 46 may have a generally constant thickness and may be applied to the substrate 44 by any of a number of known techniques, for example, bonding the superhard material 46 to the surface of the substrate 44. For example, the layer of superhard material 46, e.g., PCD, may be applied to the substrate 44 by any of a number of techniques, bonding the layer of superhard material 46 to the surface of the substrate 44. The following patent documents disclose exemplary polycrystalline diamond compositions as well as exemplary techniques for applying a layer of polycrystalline diamond to the surface of a substrate: U.S. Pat. No. 4,063,909, Mitchell; U.S. Pat. No. 4,604,106, Hall et al.; U.S. Pat. No. 4,694,918, Hall; and U.S. Pat. No. 4 811 801, Salesky et al.

[0019] According to another aspect of the invention, the hard cutting tip 42 is structured and arranged to include a partially frustoconical tip portion 48 having a first lateral tip edge 50 and an opposite second lateral tip edge 52. In one aspect, the partially frustoconical tip portion 48 is continuous from the first lateral tip edge 50 to the second lateral tip edge 52.

[0020] According to another aspect of the invention, the hard cutting tip 42 is structured and arranged to also include a first lateral tip surface 54 having a first lateral transition tip edge 56 and an opposite first terminal tip edge 58. The first lateral transition tip edge 56 is structured and arranged to be adjacent, contiguous, or connected to the first lateral tip edge 50 of the partially frusto-conical tip portion 48. The hard cutting tip 42 also includes a second lateral tip surface 60 having a second lateral transition tip edge 62 and an opposite second terminal tip edge 64. The second lateral transition tip edge 62 is structured and arranged to be adjacent, contiguous, or connected to the second lateral tip edge 52 of the partially frusto-conical tip portion 48.

[0021] The hard cutting tip 42 is further structured and arranged such that the first end tip edge 58 is adjacent to, contiguous with, or connected to the second end tip edge 64 to form a tip cutting edge 66.

[0022] In one aspect, at least a portion of the first side tip surface 54 and the second side tip surface 60 is generally planar or flat. In another aspect, the partially frusto-conical portion 22 of the head portion 18 is adjacent, aligned, contiguous, or connected to the partially frusto-conical tip portion 48 of the hard cutting tip 42. In another aspect, the first side surface 28 of the head portion 18 is adjacent, aligned, contiguous, or connected to the first side tip surface 54 of the hard cutting tip 42. In another aspect, the second side surface 34 of the head portion 18 is adjacent, aligned, contiguous, or connected to the second side tip surface 60 of the hard cutting tip 42.In yet another aspect, the cutting edge 40 of the head portion 18 is adjacent, aligned with, adjacent to, or connected to the tip cutting edge 66 of the hard cutting tip 42.

[0023] Advantageously, the described configuration of the hard cutting tip 42 improves the overall strength, durability, wear resistance, and / or cutting performance of the cutting tool 10. In addition, the invention advantageously provides a wedge effect to assist in separating the substrate and yielding larger particles, thus reducing the debris generated during the cutting process.

[0024] The hard cutting tip 42 is structured and arranged to further include a nose tip 68. In one aspect, the nose tip 68 is structured and arranged to be offset from the central longitudinal axis AA of the cutting tool body 12. In other words, in one aspect, the central longitudinal axis AA does not pass through the nose tip 68.

[0025] Advantageously, the described configuration of the nose tip 68 offset from the central longitudinal axis AA improves the overall strength, durability and / or cutting performance of the cutting tool 10.

[0026] Although specific aspects of this invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that numerous changes may be made in the details of the present invention without departing from the invention as defined in the appended claims.

Claims

[1] Cutting tool (10) for use in acting on earth strata, the cutting tool (10) being a non-rotating type tool and comprising: a cutting tool body (12) having a central longitudinal axis (AA), an axial front end (14), an axial rear end (16), a head portion (18) adjacent to the axial front end (14), and a shank portion (20) adjacent to the axial rear end (16), the head portion (18) comprising: a partially frustoconical portion (22) having a first side edge (24) and a second side edge (26); a first side surface (28) having a first lateral transition edge (30) and a first end edge (32), the first lateral transition edge (30) being adjacent to the first side edge (24) of the partially frustoconical portion (22); and a second side surface (34) having a second lateral transition edge (36) and a second end edge (38), the second lateral transition edge (36) being adjacent to the second side edge (26) of the partially frustoconical portion (22) and the first end edge (32) being adjacent to the second end edge (38) to form a cutting edge (40); and a hard cutting tip (42) attached to the axial front end (14) of the cutting tool body (12); wherein the head portion (18) is not rotationally symmetrical with respect to the central longitudinal axis (AA). [2] The cutting tool of claim 1, wherein the first side surface (28) is generally flat. [3] Cutting tool according to claim 2, wherein the first side surface (28) is coated with a wear-resistant material. [4] The cutting tool of claim 1, wherein the second side surface (34) is generally flat. [5] Cutting tool according to claim 4, wherein the second side surface (34) is coated with a wear-resistant material. [6] Cutting tool according to claim 1, wherein the hard cutting tip (42) comprises: a partially frustoconical tip portion (48) having a first lateral tip edge (50) and a second lateral tip edge (52); a first lateral tip surface (54) having a first lateral transition tip edge (56) and a first terminal tip edge (58), the first lateral transition tip edge (56) being adjacent to the first lateral tip edge (50) of the partially frustoconical tip portion (48); and a second lateral tip surface (60) having a second lateral transition tip edge (62) and a second terminal tip edge (64), the second lateral transition tip edge (62) being adjacent to the second lateral tip edge (52) of the partially frustoconical tip portion (48) and the first terminal tip edge (58) being adjacent to the second terminal tip edge (64) to form a tip cutting edge (66). [7] The cutting tool of claim 6, wherein the first side tip surface (54) is generally flat. [8] The cutting tool of claim 6, wherein the second side tip surface (60) is generally flat. [9] The cutting tool of claim 6, wherein the partially frusto-conical portion (22) of the head portion (18) is adjacent to the partially frusto-conical tip portion (48) of the hard cutting tip (42). [10] The cutting tool of claim 6, wherein the first side surface (28) of the head portion (18) is adjacent to the first side tip surface (54) of the hard cutting tip (42). [11] The cutting tool of claim 6, wherein the second side surface (34) of the head portion (18) is adjacent to the second side tip surface (60) of the hard cutting tip (42). [12] Cutting tool according to claim 6, wherein the cutting edge (40) of the head portion (18) is aligned with the tip cutting edge of the hard cutting tip (42). [13] The cutting tool of claim 6, further comprising the hard cutting tip (42) having a nose tip (68) offset from the central longitudinal axis (AA) of the cutting tool body (12). [14] The cutting tool of claim 6, wherein the hard cutting tip (42) comprises a substrate (44) and a layer of superhard material (46) adhered to the substrate (44). [15] The cutting tool of claim 14, wherein the layer of superhard material (46) comprises polycrystalline diamond (PCD) or polycrystalline cubic boron nitride (PcBN).

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