Patent Application
20190177954
The present disclosure relates generally to an implement cutting edge, and more particularly, to an implement cutting edge with brazed white cast iron teeth.
Machines, for example motor graders, dozers, wheel loaders, and excavators are commonly used in material moving applications. These machines include a ground engaging tool having a cutting edge component configured to contact the material. For example, motor graders are typically used to perform displacement, distribution and leveling of material, such as rock and/or soil. The motor graders may move the ground engaging tool over the ground so that the cutting edge component engages with the rock and/or soil so as to displace, distribute, or level the rock and/or soil.
During use of the cutting edge component, the material may abrade the cutting edge component, causing it to erode away. Accordingly, the cutting edge component may be removably attached to the ground engaging tool and replaced on a periodic basis. Conventional cutting edge components may be formed as a single plate of constant thickness. Such conventional cutting edge components may be relatively costly to manufacture and relatively difficult to handle due to their weight. The cutting edges on large motor graders and similar equipment experience very high rates of wear. Therefore, customers of such heavy duty equipment are seeking solutions that provide significant improvements in the wear life of the cutting edges while minimizing associated cost increases.
A wear component for use on an excavator is described in U.S. Pat. No. 9,027,266 (the '266 patent) issued to Maher et al. Specifically, the wear component of the '266 patent includes a shell formed from a tough metal such as carbon steel and an inner body formed from an abrasion resistant metal such as a chromium white iron. The shell is provided with cross portions extending through the inner body, with the cross portions being made of the tough metal. While the wear component of the '266 patent may strengthen the overall toughness and abrasion resistance of a work tool on earth moving equipment, the configuration of the shell and complexities in the process of joining the shell to a work tool may be prohibitively expensive and result in excessive downtime during repair or replacement of the wear component.
The disclosed cutting edge component with brazed white cast iron teeth is directed to overcoming one or more of the problems set forth above and other problems associated with conventional implement cutting edges.
In one aspect, the present disclosure is directed to a cutting edge component for a work tool on an earth-moving machine. The cutting edge component may include a longitudinally-extending wear component and a support surface connectable to a moldboard of the earth-moving machine, wherein the wear component includes at least one wear portion connected to the support surface, and the at least one wear portion forms at least one ground engaging edge. The at least one wear portion may include a mild steel body and a plurality of longitudinally-spaced white cast iron teeth vacuum brazed along a distal, ground engaging edge of the mild steel body, the plurality of teeth each being shaped with two intersecting substantially planar surfaces arranged to mate with at least a surface extending between the distal, ground engaging edge and at least one of a rearward-facing surface of the mild steel body and a front-facing surface of the mild steel body on at least one of a side of the mild steel body facing away from a direction of travel of the machine and a side of the mild steel body facing in a direction of travel of the machine to form a brazed joint. Each tooth may also include a material directing feature defined along a front-facing surface of each tooth when the tooth is brazed to the mild steel body.
In another aspect, the present disclosure is directed to a wear component for a work tool on an earth-moving machine. The wear component may include at least one wear portion including at least one ground engaging edge, and the at least one wear portion may include a mild steel body and a plurality of longitudinally-spaced white cast iron teeth vacuum brazed along the at least one ground engaging edge. The plurality of teeth may each be shaped with two intersecting substantially planar surfaces arranged to mate with at least a surface extending between the at least one ground engaging edge and at least one of a rearward-facing surface of the mild steel body and a front-facing surface of the mild steel body on at least one of a side of the mild steel body facing away from a direction of travel of the machine and a side of the mild steel body facing in the direction of travel of the machine to form a brazed joint. Each tooth may also include a material directing feature defined in a front-facing surface of each tooth when the tooth is brazed to the mild steel body.
In another aspect, the present disclosure is directed to a method of forming a cutting edge component for a work tool on an earth-moving machine. The method may include preparing a main body of an existing cutting edge component for vacuum brazing and casting a plurality of white cast iron teeth. Each of the plurality of teeth may be shaped with two intersecting planar surfaces that form an angle with each other arranged to mate with at least a surface extending between a distal, ground engaging edge and at least one of a rearward-facing surface of the main body and a front-facing surface of the main body. The method may further include vacuum brazing the plurality of white cast iron teeth along the distal, ground engaging edge of the main body.
An exemplary embodiment of a machine 10 is illustrated in
The machine 10 may also include one or more ground engaging tools 30. The ground engaging tool(s) 30 may include one or more wear components, such as one or more cutting edge components 40. In the case of a motor grader, as shown in
In the embodiment of the motor grader shown in
The terms “distal” and “proximal” are used herein to refer to the relative positions of components or features of the exemplary cutting edge components along the lateral dimension. When used herein, “distal” refers to one end of a cutting edge component in the lateral dimension, e.g., the ground engaging edge of a cutting edge component. In contrast, “proximal” refers to the end of a cutting edge component that is opposite the distal end in the lateral dimension, e.g., the proximal edge 230 of each cutting edge component 410, 510, 610, as shown in
While the cutting edge components shown in
Each cutting edge component may be replaceable to help ensure productivity and/or efficiency of the machine 10. For example, each cutting edge component 410, 510, 610, 420, 520, 620 may be removably connected to the support surface 214 of a ground engaging tool by way of one or more fasteners 216, such as bolts, inserted through one or more mounting holes formed along a longitudinal extent of a portion of each cutting edge component near proximal edge 230.
An exemplary cutting edge component 410 is shown in
The main body of cutting edge component 410, 510, 610, 420, 520, 620 may be an existing cutting edge part made from a mild steel. Mild steel is a type of carbon steel with a low amount of carbon, and is also known as “low carbon steel”. Although ranges vary depending on the source, the amount of carbon typically found in mild steel is 0.05% to 0.25% by weight, whereas higher carbon steels are typically described as having a carbon content from 0.30% to 2.0% by weight. The mild steel is typically more ductile, machinable, and weldable than high carbon and other steels, but is difficult to harden and strengthen through heating and quenching. Improved wear resistance of the cutting edge component is obtained according to various embodiments of this disclosure by vacuum brazing teeth 220, 720 made from superior wear resistant materials along the distal, ground engaging edge 240 of the mild steel main body. Details of tooth 220 are shown in
In various exemplary implementations according to this disclosure, each white cast iron tooth 220, 720 may be cast in a shape designed to mate along a distal, ground engaging edge 240 of an existing wear component 212, typically made from a mild steel. The teeth 220, 720 may be vacuum brazed directly to the ground engaging edge 240 of the main body of the wear component without the need for an intermediate mild steel base. The teeth 220, 720 may also be vacuum brazed directly to the ground engaging edge 240 without the need to perform any machining operations to the existing wear component 212, other than some fine finishing operations to clean up surfaces to be brazed. The custom cast shape of teeth 220, 720 conforming to the configuration of distal, ground engaging edge 240 of the main body of an existing wear component 212 also eliminates any requirement to weld an intermediate mild steel base to the ground engaging edge of the wear component. As shown in the perspective view of
In an alternative embodiment, intersecting brazing surfaces 731, 732 of each tooth 720 may be configured to mate with a front-facing surface of wear component 212 and distal, ground engaging edge 240. Embodiments including teeth 720 brazed along a front-facing surface of wear component 212 may be able to withstand higher loads during an earth moving operation on larger machines as the loads impacting each tooth may be largely absorbed by wear component 212 and put less stress on the brazed joint.
In exemplary embodiments including teeth brazed along a rearward-facing surface of wear component 212, the front-facing surface of each tooth with groove 233 may be arranged approximately coplanar with a front-facing surface of the mild steel body when the tooth is brazed to the mild steel body. The term “approximately coplanar” refers to coplanar within standard machining, brazing, and other manufacturing and assembly tolerances. One of ordinary skill in the art will recognize that it is not required for the front-facing surface of each tooth 220 to be coplanar with the front-facing surface of the mild steel body of the wear component 212. Alternative implementations may include the front-facing surfaces of each of the teeth 212 extending an amount forward of the forward-facing surface of the main body of wear component 212, or even lying in a plane that is an amount rearward of the forward-facing surface of the mild steel body. Each of the brazing surfaces 231, 232 may be ground or otherwise finish machined to form a flat, smooth surface suitable for brazing to the wear component. In an exemplary embodiment, each of brazing surfaces 231, 232 may be ground to be flat within approximately 0.1 mm, and along with the mating surfaces on the wear component, may be finished so that any gap between the mating surfaces is less than approximately 0.2 mm. The process of vacuum brazing the white cast iron teeth 220 along the distal, ground engaging edge 240 of each wear component 212 may include control of a number of factors including, but not limited to, braze alloy selection, finish of the mating surfaces on both the white cast iron teeth and the mild carbon steel main body of the wear component, cleaning of the surfaces before a vacuum brazing operation, fixture design for holding the teeth against the wear component during the brazing operation, braze furnace environment, temperatures, and cycles, etc.
In the alternative embodiments shown in
The various disclosed embodiments of cutting edge components with white cast iron teeth vacuum brazed along a distal, ground engaging edge 240 include different configurations and arrangements of the teeth 220 along distal, ground engaging edge 240. In the exemplary embodiments of
The brazing surfaces 231, 232 of each tooth 220, and the brazing surfaces 731, 732 if each tooth 720 may be arranged with a stress-relieving, arcuate-shaped recess 237, 737 or groove formed at the intersections of the brazing surfaces with each other and with a surface of tooth 220, 720 designed to contact the distal, ground engaging edge 240 of wear component 212. The arcuate-shaped recesses 237, 737 may be designed to eliminate any high stress regions that may develop at sharp-angled intersections between cast surfaces on the white cast iron teeth 220, 720.
As best seen in
The sides of the grooves 233 may form edges 234, 235 with the front-facing surface of tooth 220. The edges 234, 235 may serve as self-sharpening teeth as wear progresses on the front-facing surface of tooth 220. As the front-facing surface of tooth 220 wears away, unworn and sharpened portions of edges 234, 235 become exposed, and therefore edges 234, 235 may be self-sharpening.
In some embodiments, the enhanced wear resistance of the white cast iron teeth 220, 720 may be still further enhanced by coating grooves 233, and ridges 733 formed along the front-facing surface of each tooth with a coating of abrasion resistant material. For example, the bottom surfaces, sides, and/or edges 234, 235 of grooves 233 may be coated with the abrasion resistant material. The abrasion resistant material may include a carbide (e.g., tungsten carbide, titanium carbide, and/or chromium carbide) and/or a metal oxide (e.g., aluminum oxide and/or chromium oxide). The abrasion resistant material, e.g., in particle form, may be applied to the grooves 233 by welding, plasma transfer arc deposition, and/or laser deposition. In some exemplary embodiments, the coating may not fill in grooves 233, thereby allowing grooves 233 to maintain the profile of the bottom surface, sides, edges 234, 235, and depth. Alternatively, the coating may fill the grooves 233.
As shown in
The disclosed cutting edge components with wear portions that include white cast iron teeth 220, 720 brazed along a distal, ground engaging edge 240 of an existing mild steel wear component 212 may be applicable to any machine having a ground engaging tool. Several advantages may be associated with the cutting edge components according to various embodiments of this disclosure. The cutting edge components may exhibit improved penetration performance and longer wear life. For example, the cutting edge components may penetrate and break up hard and/or frozen ground, and may direct the flow of material passing by the cutting edge component when the cutting edge component is moved horizontally and/or vertically into the ground. Additionally, the disclosed embodiments with white cast iron teeth 220, 720 vacuum brazed along the distal, ground engaging edge 240 of an existing wear component 212 eliminate the need for an intermediate mild steel base to which the teeth must first be attached before the base can then be attached to an existing wear component, and eliminate any requirement to weld to existing support surfaces on wear components. Moreover, the custom cast shapes of the teeth enable mating and vacuum brazing of the teeth directly to existing cutting edge parts, with the cast shape providing improved sharpness, reduced soil cutting forces, improved flow of material past the teeth on the wear portions of the cutting edge component, and improved cutting efficiency of the disclosed cutting edge components.
The cast teeth 220, 720 of the wear portions on the cutting edge components may each have brazing surfaces formed along portions of the teeth that mate with either chamfered rearward-facing surfaces of an existing wear component 212, or a front-facing surface of an existing wear component 212. A front-facing surface of each tooth 220 may include material directing features such as one or more of at least one of a centrally positioned groove 233 that intersects with the front-facing surface along edges that provide self-sharpening cutting edges for each tooth, and a centrally positioned ridge 733. The grooves 233 and ridges 733 also increase the length of contact between the front-facing surface of each tooth 220, 720 and the ground being operated on by the cutting edge components, thereby increasing penetration force for the same amount of power expended in moving the cutting edge components through the soil. The custom cast shapes of teeth 220, 720 along the distal, ground engaging edges of wear components 212 may include tapered side surfaces extending between a rearward-facing surface of each tooth and the front-facing surface. The tapering of the width and/or thickness of each tooth 220, 720 along the sides of the tooth may form a chisel-like member at the ground engaging edge for penetrating and breaking up hard and/or frozen ground, e.g., when the cutting edge components 410, 510, 610, 420, 520, 620 with teeth 220, 720 move horizontally and/or vertically into the ground. Cast teeth 220, 720 may also be spaced along a distal, ground engaging edge of each cutting edge component in different configurations and spacings to achieve different results and/or to provide more effective penetration of different ground materials.
The arrangements of the cast teeth 220, 720 along the distal, ground engaging edge of each cutting edge component 410, 510, 610, 420, 520, 620 may include individual teeth 220, 720 that are each spaced a selected distance from an adjacent tooth, pairs of teeth 220, 720 that are arranged with each of the two teeth in each pair of teeth positioned immediately adjacent to each other, and with each pair of teeth being spaced a selected distance from an adjacent pair of teeth, and all teeth along the ground engaging edge being immediately adjacent and abutting against each other. The spacing of the teeth from each other, or the spacing of different groups of teeth from each other, along with the amount of taper of the sides of the teeth may be selected to allow the flow of material that is broken up by the ground engaging edge to pass between the teeth. The widths and spacing of the teeth 220, 720 may be different depending on the intended function of the cutting edge component as well as the dimensions of an existing wear component 212 to which the teeth 220, 720 are to be brazed. Also, the spacing (e.g., the width of the gaps between the teeth) of the teeth 220, 720 of the cutting edge components 410, 510, 610, 420, 520, 620 may depend at least in part on the size of the particles of the material broken up by the ground engaging edge.
The cutting edge components 410, 510, 610, 420, 520, 620 may also be constructed for optimal placement of the white cast iron teeth 220, 720 along the ground engaging edge 240 of a wear component 212 to reduce weight, cost, and the amount of material at the end of life of the cutting edge components. The custom cast shape of each tooth 220, 720 may be selected to optimize the penetration capabilities of the tooth and the wear life of the tooth, while minimizing costs associated with the amount of material and processing required to form each tooth.
It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed cutting edge components. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosed cutting edge components. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.
