Patent Application
20130300183
The invention pertains to a rotatable cutting tool that is useful for the impingement of earth strata such as, for example, asphaltic roadway material, coal deposits, mineral formations and the like. More specifically, the present invention pertains to a rotatable cutting tool that is useful for the impingement of earth strata wherein the cutting tool body possesses improved design so as to provide for improved performance characteristics for the rotatable cutting tool.
Rotatable cutting tools have been used to impinge earth strata such as, for example, asphaltic roadway material or ore bearing or coal bearing earth formations or the like. Generally speaking, these kinds of rotatable cutting tools have an elongate cutting tool body (typically made from steel) and a hard tip (or insert) affixed to the cutting tool body at the axial forward end thereof. The hard tip is typically made from a hard material such as, for example, cemented (cobalt) tungsten carbide. The rotatable cutting tool is rotatably retained or held in the bore of a tool holder or, in the alternative, in the bore of a sleeve that is in turn held in the bore of a holder.
The holder is affixed to a driven member such as, for example, a driven drum of a road planing machine. In some designs, the driven member (e.g., drum) carries hundreds of holders wherein each holder carries a rotatable cutting tool. Hence, the driven member may carry hundreds of rotatable cutting tools. The driven member is driven (e.g., rotated) such that the hard tip of each one of the rotatable cutting tools impinges or impacts the earth strata (e.g., asphaltic roadway material) thereby fracturing and breaking up the material into debris. The ability of the individual tools to most effectively fracture and break up the material into debris of a desired size is an important characteristic and design feature of the cutting tool.
As can be appreciated, during operation the entire rotatable cutting tool is typically subjected to a variety of extreme cutting forces and stresses in an abrasive and erosive environment. Rotatable cutting tools having a cutting tool body with various shapes and designs have been provided to most efficiently and effectively operate in these extreme cutting environments. Such cutting tools are designed to be rotatable in order to maintain the sharpness and cutting effectiveness of the tool while promoting even wear of the tool.
It, therefore, becomes apparent that it is important and desirable that a cutting tool possess the requisite design and strength to maintain its integrity during the intended useful life of the rotatable cutting tool while still providing an efficient and effective rotatable cutting tool for effectively cutting or breaking the material that it impacts. Thus, it would be desirable to provide an improved cutting tool that overcomes disadvantages, shortcomings and limitations of known cutting tools.
In accordance with an aspect of the invention, a rotatable cutting tool for use in impinging earth strata includes a cutting tool body having a central longitudinal axis, the cutting tool body including a head portion, a collar portion axially rearward of the head portion, and a shank portion axially rearward of the collar portion. The cutting tool also includes a hard cutting tip affixed to the head portion of the cutting tool body. The head portion includes a first head section adjacent to an axial forward end of the head portion, wherein the first head section includes a plurality of first side faces such that adjacent first side faces meet to form a corresponding plurality of first common edges. The head portion further includes a second head section adjacent to an axial rearward end of the head portion, the second head section having a plurality of second side faces wherein adjacent second side faces meet to form a corresponding plurality of second common edges.
In accordance with another aspect of the invention, a rotatable cutting tool for use in impinging earth strata includes a cutting tool body having a central longitudinal axis, the cutting tool body including a head portion, a shank portion axially rearward of the head portion and a hard cutting tip affixed to the head portion of the cutting tool body. The head portion includes a first head section adjacent to an axial forward end of the head portion, the first head section having a plurality of first side faces wherein adjacent first side faces meet to form a corresponding plurality of first common edges. The head portion also includes a second head section adjacent to an axial rearward end of the head portion, the second head section having a plurality of second side faces wherein adjacent second side faces meet to form a corresponding plurality of second common edges. The plurality of first side faces are generally planar and each extend longitudinally in a first plane at a first angle relative to the central longitudinal axis of the cutting tool body and the plurality of second side faces are generally planar and each extend longitudinally in a second plane at a second angle relative to the central longitudinal axis. In one aspect, the first angle is substantially the same as the second angle. In another aspect, the first angle is different than the second angle.
In accordance with another aspect of the invention, a rotatable cutting tool for use in impinging earth strata includes a cutting tool body having a central longitudinal axis, the cutting tool body including a head portion, a shank portion axially rearward of the head portion and a hard cutting tip affixed to the head portion of the cutting tool body. The head portion includes a first head section adjacent to an axial forward end of the head portion, the first head section having a plurality of first side faces wherein adjacent first side faces meet to form a corresponding plurality of first common edges. The head portion also includes a second head section adjacent to an axial rearward end of the head portion, the second head section having a plurality of second side faces wherein adjacent second side faces meet to form a corresponding plurality of second common edges. The plurality of first side faces are offset from the plurality of second side faces.
These and other aspects of the present invention will be more fully understood following a review of this specification and drawings.
Referring to
Cutting tool 10 has a central longitudinal axis X-X. Cutting tool 10 includes an elongate body, generally designated as 12, which typically is made of, for example, steel. Elongate body 12 has an axial forward end 14 and an axial rearward end 16.
Elongate body 12 further includes a head portion 18 adjacent the axial forward end 14 and a shank portion 20 adjacent the axial rearward end 16. A collar portion 21 may be formed between the head portion 18 and the shank portion 20, but is not required. The shank portion 20 may be provided with various shapes and configurations. In one aspect, the shank portion 20 may be structured and arranged to be rotatable such that the cutting tool 10 is a rotatable type cutting tool. In another aspect, the shank portion 20 may be structured and arranged to be non-rotatable such that the cutting tool 10 is a non-rotatable type cutting tool.
In accordance with another aspect of the invention, the cutting tool 10 further includes a hard cutting tip, generally designated as reference number 22 adjacent the axial forward end 14. The hard cutting tip 22 may be affixed by, for example, brazing the hard cutting tip 22 to, for example, a socket (not shown) that is typically formed in the head portion 18 adjacent the axial forward end 14 of the body 12.
In one aspect, the hard cutting tip 22 is structured and arranged so as to include a substrate 26 (see, for example,
The layer of superhard material 28 may have a generally constant thickness and can be applied to the substrate 26 by any one of the number of known techniques wherein the superhard material 28 is, for example, bonded to the surface of the substrate 26. For example, one can apply the layer of superhard material 28, e.g. PCD, to the substrate 26 by any one of a number of techniques wherein the layer of superhard material 28 is bonded to the surface of the substrate 26. The following patent documents disclose exemplary compositions of polycrystalline diamond as well as exemplary techniques to apply a layer of polycrystalline diamond to the surface of a substrate: U.S. Pat. No. 4,063,909 to Mitchell, U.S. Pat. No. 4,604,106 to Hall et al., U.S. Pat. No. 4,694,918 to Hall, and U.S. Pat. No. 4,811,801 to Salesky et al.
Still referring to
The first head section 30 is structured and arranged to include a plurality of first side faces 38 wherein adjacent first side faces 38 meet to form plurality of first common edges 40. In one aspect, the plurality of first side faces 38 are continuous about the first head section 30, i.e. extend around the entire perimeter of the first head section 30.
The second head section 34 is structured and arranged to include a plurality of second side faces 42 wherein adjacent second side faces 42 meet to form plurality of second common edges 44. In one aspect, the plurality of second side faces 42 are continuous about the second head section 34, i.e. extend around the entire perimeter of the second head section 34.
In another aspect of the invention, the first head section 30 and the second head section 34 are adjoined at or meet to form a sectional boundary 46 therebetween. The sectional boundary 46 divides or separates the first head section 30 and the second head section 34. It will be appreciated that if additional head sections are provided then additional sectional boundaries will exist accordingly.
The plurality of first side faces 38 each extend from the axial forward end 32 of the head portion 18 to the sectional boundary 46. In addition, the plurality of first common edges 40 also each extend from the axial forward end 32 of the head portion 18 to the sectional boundary 46.
The plurality of second side faces 42 each extend from the axial rearward end 36 of the head portion 18 to the sectional boundary 46. In addition, the plurality of second common edges 44 also each extend from the axial rearward end 36 of the head portion 18 to the sectional boundary 46.
In an aspect of the invention, the plurality of first side faces 38 are structured and arranged to be offset from the plurality of second side faces 42. In another aspect, the first head portion 30 having the plurality of first side faces 38 and the second head portion 34 having the plurality of second side faces 42 are structured and arranged to be out of time with one another.
In another aspect, the plurality of first common edges 40 and the second common edges 44 are structured and arranged such that none of the plurality of first common edges 40 are aligned with any of the second common edges 44. In one example, each of the plurality of first common edges 40 are generally aligned with a longitudinal centerline C1 of corresponding adjacent second side faces 42 of the second head portion 34. In another example, each of the plurality of second common edges 44 are generally aligned with a longitudinal centerline C2 of corresponding adjacent first side faces 38 of the first head portion 30.
In accordance with another aspect of the invention, the plurality of second side faces 42 and the plurality of second common edges 44 are structured and arranged to form a raised projection 48 adjacent the sectional boundary 46. More particularly, adjacent side faces 42 and the second common edge 44 extending therebetween are structured and arranged to be raised above a corresponding adjacent first side face 38 such that the raised projection 48 is provided.
In an aspect of the invention, the plurality of first side faces 38 are generally planar and each extend longitudinally in a first plane at a first angle A (see
Advantageously, the described configuration including, for example, the offset first side faces 38 and second side faces 42 along with the raised projection 48 improves the operating efficiency and reliability of the cutting tool 10. For example, these features improve the ability of the cutting tool 10 to rotate during operation which is important for the self-sharpening aspects of these types of tools. In addition, these features improve the ability of the cutting tool 10 to break up and fracture material during operation, as well as, provides for increased comminution, i.e. reduction of size, and mixing action in stabilization and pulverizing operations.
Whereas particular aspects of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.
