BACKGROUND OF THE INVENTION
Efficient degradation of materials is important to a variety of industries including the asphalt, mining, and excavation industries. In the asphalt industry, pavement may be degraded using attack tools, and in the mining industry, attack tools may be used to break minerals and rocks. Attack tools may also be used when excavating large amounts of hard materials. In asphalt recycling, often, a drum supporting an array of attached attack tools may be rotated and moved so that the attack tools engage a paved surface causing the tools, which typically have a tungsten carbide tip, to wear. Much time is wasted in the asphalt recycling industry due to high wear of the tools.
U.S. Pat. No. 6,733,087 to Hall et al., which is herein incorporated by reference for all that it contains, discloses an attack tool for working natural and man-made materials that is made up of one or more segments, including a steel alloy base segment, an intermediate carbide wear protector segment, and a penetrator segment comprising a carbide substrate that is coated with a superhard material. The segments are joined at continuously curved interfacial surfaces that may be interrupted by grooves, ridges, protrusions, and posts. At least a portion of the curved surfaces vary from one another at about their apex in order to accommodate ease of manufacturing and to concentrate the bonding material in the region of greatest variance.
BRIEF SUMMARY OF THE INVENTION
In one aspect of the invention, an attack tool for degrading materials comprises a base segment comprising an attachment to a driving mechanism, a first wear-resistant segment bonded to the base segment, a second wear-resistant segment bonded to the first wear-resistant segment at a brazed joint opposite the base segment, and at least a portion of exterior surfaces of both the wear-resistant segments proximate the joint, the portion of exterior surfaces comprising a finish ground surface.
In another aspect of the invention, a method for manufacturing an attack tool is also disclosed. The method may comprise the steps of providing a first wear-resistant segment and providing a superhard material bonded to a second wear-resistant segment, forming a joint by brazing the first and second wear-resistant segments together, and removing by grinding a braze-induced affected zone proximate the brazed joint.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional diagram of an embodiment of an attack tool on a rotating drum attached to a motor vehicle.
FIG. 2 is an orthogonal diagram of another embodiment of an attack tool and a holder.
FIG. 3 is a cross-section of a perspective diagram of another embodiment of an attack tool.
FIG. 4 is a cross-sectional diagram of an embodiment of an attack tool that includes a first wear-resistant segment, a second wear-resistant segment, a brazed joint, and a braze-affected zone.
FIG. 5 is a cross-sectional diagram of the embodiment of the attack tool illustrated in FIG. 4 in which a braze-affected zone has been removed and a portion of an exterior surface of the first and second wear-resistant segments includes a finish ground surface.
FIG. 6 is a cross-sectional diagram of the embodiment of the attack tool illustrated in FIG. 4 in which the braze-affected zone will be removed and a finish grinding of a portion of an exterior surface of the first and second wear resistant segments is performed by an embodiment of a grinding tool.
FIG. 7 is a cross-sectional diagram of the embodiment of the attack tool illustrated in FIG. 4 in which the braze-affected zone will be removed and a finish grinding of a portion of an exterior surface of the first and second wear resistant segments is performed by another embodiment of a grinding tool.
FIG. 8 is a cross-sectional diagram of another embodiment of an attack tool that includes another embodiment of a finish ground surface of an exterior surface of a first and second wear resistant segments.
FIG. 9 is a cross-sectional diagram of an attack tool that includes another embodiment of a finish ground surface of an exterior surface of a first and second wear resistant segments.
FIG. 10 is a side-view of an embodiment of a second wear-resistant segment and a superhard material bonded to the second wear-resistant segment.
FIG. 11 is a side-view of another embodiment of a second wear-resistant segment and a superhard material bonded to the second wear-resistant segment.
FIG. 12 is a side-view of another embodiment of a second wear-resistant segment and a superhard material bonded to the second wear-resistant segment.
FIG. 13 is a side-view of another embodiment of a second wear-resistant segment and a superhard material bonded to the second wear-resistant segment.
FIG. 14 is a side-view of another embodiment of a second wear-resistant segment and a superhard material bonded to the second wear-resistant segment.
FIG. 15 is a side-view of another embodiment of a second wear-resistant segment and a superhard material bonded to the second wear-resistant segment.
FIG. 16 is a cross-sectional diagram of an embodiment of a sacrificial material at a brazed joint between a first wear-resistant segments and a second wear-resistant segment.
FIG. 17 is a cross-sectional diagram of an embodiment of a non-planar interface between a first wear-resistant segment and a second wear-resistant segment.
FIG. 18 is a cross-sectional diagram of another embodiment of a first wear-resistant segment and a second wear-resistant segment.
FIG. 19 is a cross-sectional diagram of another embodiment of a first wear-resistant segment and a second wear-resistant segment.
FIG. 20 is a cross-sectional diagram of an embodiment of a second wear-resistant segment brazed into a pocket of a first wear-resistant segment.
FIG. 21 is a cross-sectional diagram of another embodiment of an attack tool.
FIG. 22 is a cross-sectional diagram of another embodiment of an attack tool.
FIG. 23 is a cross-sectional diagram of another embodiment of an attack tool.
FIG. 24 is a cross-sectional diagram of another embodiment of an attack tool.
FIG. 25 is a schematic of an embodiment of a method for manufacturing an attack tool.
FIG. 26 is a schematic of another embodiment of a method for manufacturing an attack tool.
DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT
It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, may be arranged and designed in a wide variety of different configurations. FIG. 1 is a cross-sectional diagram of an embodiment of an attack tool 101a on a driving mechanism 102 attached to a motor vehicle 103. The driving mechanism 102 may be a rotating drum. The motor vehicle 103 may be a cold planer used to degrade pavement 104 prior to the placement of a new layer of pavement, or a mining vehicle used to degrade natural formations. Attack tools 101a are attached to the driving mechanism 102, which rotates so that the attack tools 101a engage and degrade the pavement 104. The pavement 104 may cause substantial wear on the attack tools 101a. When the attack tools 101a wear enough, the attack tools 101a need to be replaced. The maintenance required to replace these attack tools 101a may be burdensome and costly because of down time.
FIG. 2 is an orthogonal diagram of an embodiment of an attack tool 101b secured within a holder 201. The holder 201 may be secured to a driving mechanism, such as the driving mechanism 102 illustrated in FIG. 1. The holder 201 may hold the attack tool 101b at an angle to increase the degradation efficiency of the attack tool 101b. An end of the attack tool 101b may comprise an attachment 203a, such as a shaft. The holder 201 may support the attack tool 101b at an angle offset from the direction of rotation, such that as the attack tool 101b engages a paved surface, such as the pavement 104 illustrated in FIG. 1, the attack tool 101b rotates within the holder 201. A sheath 202 may be fitted around an attachment 203a to enable or improve the rotation of the attack tool 101b. Rotation may be beneficial in that it may result in more even wear on the attack tool 101b instead of having most of the wear concentrated on one side of the attack tool 101b.
FIG. 3 is a cross-section of a perspective diagram of another embodiment of an attack tool 101c. The attack tool 101c may comprise a base segment 301a which may be made of steel, cemented metal carbide, or combinations thereof. The base segment 301a may comprise an attachment 203b, such as a shaft, that attaches to a driving mechanism, such as the driving mechanism 102 illustrated in FIG. 1. The attack tool 101c may further comprise a first wear-resistant segment 302a that is bonded to the base segment 301a. The first wear-resistant segment 302a may comprise steel, a cemented metal carbide, tungsten, silicon, niobium, or combinations thereof. A second wear-resistant segment 303a, which may comprise steel, a cemented metal carbide, tungsten, silicon, niobium, or combinations thereof, may be bonded to the first wear resistant segment 302a at a brazed joint 304a opposite the base segment 301a.
There may also be a superhard material 305a bonded to the second wear-resistant segment 303a opposite the brazed joint 304a. The superhard material 305a may comprise a domed, rounded, semi-rounded, conical, flat, or pointed geometry, and the superhard material may further comprise natural diamond, polycrystalline diamond, boron nitride, or combinations thereof. The superhard material 305a may be bonded to the second wear-resistant segment 303a by various processes, including high pressure/high temperature, chemical vapor deposition, physical vapor deposition, or combinations thereof.
FIG. 4 is a cross-sectional diagram of an embodiment of an attack tool 101d that includes a first wear-resistant segment 302b, a second wear-resistant segment 303b, a brazed joint 304b joining the first wear-resistant segment 302b and the a second wear-resistant segment 303b, and a braze-affected zone 130a.
Preferably the first wear-resistant segment 302b and the second wear-resistant segment 303b comprise a cemented metal carbide, preferably tungsten carbide.
The brazed joint 304b may comprise a braze material comprising silver, gold, copper, nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, indium, phosphorus, molybdenum, platinum, or combinations thereof.
Excess braze material 402a may extrude to the outside of the brazed joint 304b when the first wear-resistant segment 302b and the second wear-resistant segment 303b are brazed together. Additionally, brazing may result in an affected zone 130a which is indicated by dotted lines 403a. The affected zone 130a may be weakened by cracks, depressions, scrapes, or other irregularities and/or imperfections as a result of the brazing. The affected material in the affected zone 103 in either the first wear-resistant segment 302b and the second wear-resistant segment 303b may initiate a break especially in embodiments where the first wear-resistant segment 302b and the second wear-resistant segment 303b comprise brittle materials, such as tungsten carbide.
To mitigate the effects of the affected zone 130a, and, consequently, reduce or remove any braze-induced weaknesses the first wear-resistant segment 302b and the second wear-resistant segment 303b, the affected zone 130a is removed. FIG. 5 is a cross-sectional diagram of the embodiment of the attack tool 101d illustrated in FIG. 4 in which the braze-affected zone 130a has been removed and a portion of an exterior surface 501a proximate the brazed joint 304b of the first wear-resistant segment 302b and the second wear-resistant segment 303b includes a finish ground surface 504a.
The first wear-resistant segment 302b may also comprises an outer diameter 310b and an edge 510a joined by a fillet 503. The radius of the fillet 503 may be 0.005 to 0.600 inches and may include a shelf 511 that joins the edge 510a to the fillet 503. An additional benefit of the fillet 503 may be that a stress point that results from a 90 degree angle formed by the first wear-resistant segment 302b and the second wear-resistant segment 303b before grinding is reduced. When the first wear-resistant segment 302b and the second wear-resistant segment 303b are ground as indicated in FIG. 5, the stress may be distributed away from the brazed joint 304b, extending its life.
In the embodiment of the attack tool 101d that has been processed as illustrated in FIG. 5, surfaces of the attack tool 101d, such as the edge 510a and shelf 511a, may be susceptible to high wear. A durable coating 512 may be bonded to those surfaces susceptible to high wear. The durable coating 512 may comprise diamond, polycrystalline diamond, cubic boron nitride, diamond grit, polycrystalline diamond grit, cubic boron nitride grit, or combinations thereof. The durable coating 512 may be deposited by chemical vapor deposition; physical vapor deposition; blasting diamond grit, polycrystalline diamond grit, cubic boron nitride grit, sintering or combinations thereof.
FIG. 6 is a cross-sectional diagram of the embodiment of the attack tool 101d illustrated in FIG. 4 in which the braze-affected zone 130a will be removed proximate the brazed joint 304b of the first wear-resistant segment 302b and the second wear-resistant segment 303b and a finish grinding of a portion of an exterior surface 501a to provide a finish ground surface 504a (illustrated in FIG. 5) is performed by an embodiment of a grinding tool. After brazing, excess braze material 402a may be ground away, in addition to the affected zone 130a, which includes portions of the first wear-resistant segment 302b and the second wear-resistant segment 303b f.
A grinding tool 604a, such as a dremel, may comprise a grinding element 603a attached to a shaft 601a. The grinding element 603a may rotate along an axis 602a of the shaft 601a. The grinding element 603a may comprise fine or coarse diamond grit or other materials suitable for grinding. Grinding, however, may leave small cracks, abrasions, grooves, or other irregularities and/or imperfections behind which may weaken the attack tool 101d when in use, although it is believed to still be an improvement over leaving the affected zone 130a in place. Therefore, the finish ground surface 504a may be polished. Polishing may remove irregularities and/or imperfections. In selected embodiments, grinding, lapping, hand polishing, annealing, sintering, direct firing, wet etching, dry etching, or a combination thereof, may be used to aid in polishing the attack tool 101d. In other embodiments of the grinding and polishing process, the attack tool 101d may be polished in multiple stages. In either case, a layer of material which may comprise the irregularities and/or imperfections may be removed in an effort to strengthen the attack tool 101d.
FIG. 7 is a cross-sectional diagram of the embodiment of the attack tool 101d illustrated in FIG. 4 in which the braze-affected zone 130a will be removed proximate the brazed joint 304b of the first wear-resistant segment 302b and the second wear-resistant segment 303b and a finish grinding of a portion of an exterior surface 501a to provide a finish ground surface 504a (illustrated in FIG. 5) is performed by another embodiment of a grinding tool.
The grinding tool 604b may comprise a grinding element 603b attached to a shaft 601b. The grinding element 603b may rotate along an axis 602b of the shaft 601b, and may comprise fine or coarse diamond grit or other material suitable for grinding. The shape of the grinding element 603a may be changed to form different geometries instead of a fillet, such as the fillet 503 illustrated in FIG. 5.
FIG. 8 is a cross-sectional diagram of another embodiment of an attack tool 101e that includes another embodiment of a finish ground surface of an exterior surface of a first wear-resistant segment 302c and a second wear-resistant segment 303c. The first wear-resistant segment 302c comprises an outer diameter 310c and an edge 510b joined by at least one substantially conic section 801a and a shelf 511b. The at least one conic section 801a, or a shelf 511b may comprise a finish ground surface 501b. The conic section 801a may form obtuse angles with the shelf 511b and the outer diameter 510b. These angles may still be stress points, but the stress may be spread between them and be below the brazed joint 304c. Polishing may also remove any irregularities and/or imperfections leftover from or created by grinding.
FIG. 9 is a cross-sectional diagram of another embodiment of an attack tool 101f that includes another embodiment of a finish ground surface of an exterior surface of a first wear-resistant segment 302d and a second wear-resistant segment 303d. A plurality of substantially conic sections 801b may be used to join the outer diameter 310d and edge 510c. In FIG. 9, two or more conic sections 801b and a shelf 511c are used. Again, other obtuse angles may be created when multiple conic sections 801b which may serve to further disperse the stresses encountered when the attack tool 101f is in use.
FIGS. 10 through 15 are cross-sectional diagrams of a superhard material bonded to a second wear-resistant segments. FIG. 10 shows a second wear-resistant segment 303e bonded to a superhard material 305e comprising a rounded geometry. FIG. 11 shows a second wear-resistant segment 303f bonded to a superhard material 305f comprising a domed geometry. FIG. 12 shows a second wear-resistant segment 303g bonded to a superhard material 305g comprising a conical geometry. FIG. 13 shows a second wear-resistant segment 303h bonded to a superhard material 305h comprising a semi-rounded geometry. FIG. 14 shows a second wear-resistant segment 303i bonded to a superhard material 30i5 comprising a pointed geometry. FIG. 15 shows a second wear-resistant segment 303j bonded to a superhard material 305j comprising a flat geometry. Each geometry may change the cutting properties of an attack tool, such as attack tool 101a illustrated in FIG. 1. A pointed geometry may allow for more aggressive cutting. While a rounded geometry may reduce wear by distributing stresses and make cutting less aggressive.
FIG. 16 is a cross-sectional diagram of an embodiment of a sacrificial area 1601 proximate a brazed joint 304k between a first wear-resistant segments 302k and a second wear-resistant segment 303k. Excess braze material 402b may extrude to the outside of the brazed joint 304b when the first wear-resistant segment 302k and the second wear-resistant segment 303k are brazed together for the purpose of being the sacrificial area 1601. After brazing, a affected zone 130b, indicated by the dotted lines 403b, may be contained in the sacrificial area 1601, which may then be ground away to leave the desired shape of the outer surfaces.
FIG. 17 is a cross-sectional diagram of an embodiment of a first non-planar interface 1701 between a first wear-resistant segment 302l and a second wear-resistant segment 303l. A second non-planar interface 1704 is also between the second wear-resistant segment 303l and a superhard material 305l. The non-planar interface 1701 between the first wear-resistant segment 302l and a second wear-resistant segment 303l at a brazed joint 304l may increase the area of the brazed joint 304l and strengthen the bond. Similarly, the non-planar interface 1704 between the second wear-resistant segment 303l and the superhard material 305l may also strengthen their bond. The non-planar interface 1701 between the first wear-resistant segment 302l and a second wear-resistant segment 303l may comprise at least one protrusion 1702 disposed within the second wear-resistant segment 303l that is fitted within at least one recess 1703 disposed within the first wear-resistant segment 302l. Other embodiments may include complementary curved surfaces, such as that exhibited by the second non-planar interface 1704.
In FIG. 18 a second wear-resistant segment 303m may be conical in shape. A conical shape may allow for a smaller tip 1801 while having a larger area to braze at a brazed joint 304m. Other embodiments of the second wear-resistant segment 303m include pyramidal, frustoconical, spherical, helical shapes. Also shown in FIG. 18, is that an affected zone, such as the affected zone 130a illustrated in FIG. 4, has been removed such that an outer diameter 1802 of the second wear-resistant segment 303m increases the further away from the tip 1801 one measures the outer diameter 1802, but then the outer diameter 1802 decreases as it approaches a brazed joint 304m.
In FIG. 19, a second wear-resistant segment 303n is tungsten carbide without a superhard material, such as the superhard material 305a illustrated in FIG. 3, bonded to it. The second wear-resistant segment 303n may have a non-planar interface 1701 between it and a the first wear-resistant segment 302n, which may also comprise tungsten carbide, the second wear-resistant segment 303n being brazed to the first wear-resistant segment 302. The first wear-resistant segment 302n may be bonded to a base segment 301n comprising an attachment 203b that attaches to a driving mechanism, such as the driving mechanism 102 illustrated in FIG. 1.
FIG. 20 is a cross-sectional diagram of an embodiment of a second wear-resistant segment 303o brazed into a pocket 2001 of a first wear-resistant segment 302o. The pocket 2001 may increase a surface area available for bonding the second wear-resistant segment 303o to the first wear-resistant segment 302o. The brazing process may create an affected zone 130c indicated by the dotted lines 403c that may not be entirely removable due to the location of the braze material between the first wear-resistant segment 302o and the second wear-resistant segment 303o. Some of the zone 130c may be ground to improve strength as discussed above.
FIGS. 21 through 24 are cross-sectional diagrams of various embodiments of attack tools adapted to remain stationary within their respective holders, which are attached to a driving mechanism. In FIG. 21, an attack tool 101p may comprise a base segment 301p which may comprise steel, or a cemented metal carbide. The attack tool 101p may also comprise a first wear-resistant segment 302p and a second wear-resistant segment 303p bonded at a brazed joint 304p. The brazed joint 304p may also comprise affected zones, such as the affected zone 130a in FIG. 4, which may be removed by a finish grinding process. A rake angle of a superhard material 305p may be altered to change the cutting ability of the attack tool 101p. Positive or negative rake angles may be used. The layer of superhard material 305p may be from 1 to 6000 microns thick.
In FIG. 22, an attack tool 101q may comprise a base segment 301q, a first wear-resistant segment 302q and a second wear-resistant segment 303q bonded at a brazed joint 304q, and a superhard material 305q.
In FIG. 23, an attack tool 101r may comprise a base segment 301r, a first wear-resistant segment 302r and a second wear-resistant segment 303r bonded at a brazed joint 304r, and a superhard material 305r.
In FIG. 24, an attack tool 101s may comprise a first wear-resistant segment 302s and a second wear-resistant segment 303s bonded at a brazed joint 304s, and a superhard material 305s.
FIG. 25 is a schematic of an embodiment of a method 2100 for manufacturing an embodiment of attack tools described above. The method 2100 may comprise the steps of providing 2101 a first wear-resistant segment and providing a superhard material bonded to a second wear-resistant segment, forming 2102 a brazed joint by brazing the first wear-resistant segment and the second wear-resistant segment together, and removing 2103 a braze-induced affected zone proximate the brazed joint by grinding.
In the method 2100, the wear-resistant segments may comprise steel, a cemented metal carbide, tungsten, niobium, silicon, or combinations thereof. The step for forming 2102 a joint by brazing may comprise using a braze material comprising silver, gold, copper, nickel, palladium, boron, chromium, silicon, germanium, aluminum, iron, cobalt, manganese, titanium, tin, gallium, vanadium, indium, phosphorus, molybdenum, platinum, or combinations thereof.
FIG. 26 is a schematic of another embodiment of a method 2200 for manufacturing an embodiment of attack tools described above. The method 2200 may comprise the steps of providing 2201 a first wear-resistant segment and providing a superhard material bonded to a second wear-resistant segment, forming 2202 a brazed joint by brazing the first wear-resistant segment and the second wear-resistant segments together, and removing 2203 a braze-induced affected zone proximate the brazed joint by grinding. The method 2200 may further comprise another step of polishing 2204 an outer diameter formed by removing the braze-induced affected zone. That is, when cracks, ruts, or other similar irregularities and/or imperfections may be left behind from grinding these, irregularities and imperfections may be removed by polishing the finish ground surface, which may result in a stronger tool.
Patent Grant
7950746
