Degradation assembly

Abstract

A degradation assembly comprises a rotating portion and a fixed portion. The rotating portion comprises a wear resistant tip bonded to a carbide bolster. The bolster is attached to a shaft adapted for a rotatable connection within a bore of the fixed portion. The fixed portion is adapted for a rigid connection to a driving mechanism. The fixed portion includes an O-ring slot formed within its bore and with an O-ring being disposed therein. The O-ring is at least 15 percent compressed such that the O-ring resists rotation of the shaft.

Description

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 attack tools disposed within holders, together making up a degradation assembly, may be rotated and moved so that the attack tools engage a paved surface causing the tools and/or holders to wear. Much time is wasted in the asphalt recycling industry due to high wear of the degradation assemblies, which typically have a tungsten carbide tip.

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.

Examples of degradation assemblies from the prior art are disclosed in U.S. Pat. No. 6,824,225 to Stiffler, U.S. Pat. App. Pub. No. 2005/0173966 to Mouthaan, U.S. Pat. No. 6,692,083 to Latham, U.S. Pat. No. 6,786,557 to Montgomery, Jr., U.S. Pat. App. Pub. No. 2003/0230926, U.S. Pat. No. 4,932,723 to Mills, U.S. Pat. App. Pub. No. 2002/0175555 to Merceir, U.S. Pat. No. 6,854,810 to Montgomery, Jr., U.S. Pat. No. 6,851,758 to Beach, which are all herein incorporated by reference for all they contain.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention, a degradation assembly comprises a rotating portion and a fixed portion. The rotating portion comprises a wear resistant tip bonded to a carbide bolster. The bolster is attached to a shaft adapted for a rotatable connection within a bore of the fixed portion. The fixed portion is adapted for a rigid connection to a driving mechanism. The fixed portion also comprises an O-ring slot formed within its bore and an O-ring being disposed within the bore, such that the O-ring contacts the shaft of the rotating portion. The O-ring is at least 15 percent compressed such that the O-ring resists rotation of the shaft.

The shaft may be a shank or a sleeve. The shank may be disposed within a sleeve. The shaft may also be tapered on the end attached to the bolster to aid in reducing stress risers. The shaft may be formed from a steel body which is rigidly connected to the bolster. The shaft may comprise a tapered face adapted to be attached to the bolster. The bolster may also comprise a cavity with a lip adapted to attach to a locking mechanism. The fixed portion may comprise a wire snap ring slot formed within its bore. The O-ring may comprise a diameter smaller than a diameter of a wire snap ring. The bolster may comprise a tapered base end. The bolster may be mechanically attached to the shaft or shank by a locking mechanism. The locking mechanism may be axially disposed within the fixed portion, the rotating portion, and the shaft. The locking mechanism may be adapted to lock to a cavity of the bolster. The locking mechanism may be threaded through the fixed portion. A bore of the shaft may comprise a geometry of the locking mechanism. This may aid in supporting the locking mechanism and help in stabilizing it.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a representative asphalt milling machine.

FIG. 2 is a cross-sectional diagram of an embodiment of a degradation assembly.

FIG. 3 is a cross-sectional diagram of another embodiment of a degradation assembly.

FIG. 4 is a cross-sectional diagram of another embodiment of a degradation assembly.

FIG. 5 is a cross-sectional diagram of another embodiment of a degradation assembly.

FIG. 6 is a cross-sectional diagram of another embodiment of a degradation assembly.

FIG. 7 is a cross-sectional diagram of another embodiment of a degradation assembly.

FIG. 8 is a cross-sectional diagram of another embodiment of a degradation assembly.

FIG. 9 is a perspective diagram of another embodiment of a degradation assembly.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a cross sectional diagram of an embodiment of an asphalt milling machine 100. The asphalt milling machine 100 may comprise a driving mechanism 102 attached to a motor vehicle 103. A plurality of degradation assemblies 200 may be secured to the driving mechanism 102. The driving mechanism 102 may be a rotating drum, a chain, a rotor, or combinations thereof. The asphalt milling machine 100 may degrade a paved surface 104 of a road, sidewalk, or parking lot prior to applying new pavement. The driving mechanism 102 may rotate such that the degradation assemblies 200 engage the paved surface 104 as the motor vehicle 103 moves in a direction indicated by the arrow 105. In other embodiments of the invention, the driving mechanism 102 may be attached to a mining vehicle or other drilling machine.

FIG. 2 is a cross-sectional diagram of an embodiment of the degradation assembly 200 of FIG. 1. The degradation assembly 200 may comprise a rotating portion 210 supported by a fixed portion 290 that is attached to the driving mechanism. The rotation of the rotating portion 210 may aid in degradation of material. The rotating portion 210 can include a wear resistant tip 220 bonded to a carbide bolster 230. The bolster 230 may be attached to a shaft 240, which shaft is in turn adapted for rotatable connection within a bore 292 of the fixed portion 290. The shaft 240 can include both an inner shank 250 installed within an outer sleeve 270, with the shank 250 being coupled to the bolster 230 with a coaxial locking mechanism 260 adapted to attach to a cavity 232 of the bolster 230. The cavity 232 of the bolster 230 may comprise a lip 234 adapted to attach to a head 262 of the locking mechanism 260. As shown in FIG. 2, the bolster 230 may be isolated from the fixed portion 290 by the sleeve portion 270 of the shaft 240.

The fixed portion 290 of the degradation assembly 200 may be adapted for a rigid connection to the driving mechanism. The fixed portion 290 may also comprise an O-ring slot 294 formed within its bore 292. With the shaft 240 installed in the bore 292 of the fixed portion, the O-ring 280 may be at least 15 percent compressed such that the O-ring resists rotation of the shaft 240 within the bore. It is believed that an O-ring 280 resisting rotation of the shaft 240 will aid in resisting wear of the rotating portion 210 of the degradation assembly 200. It is also believed that an O-ring 280 may prevent debris from entering the assembly 200. The O-ring 280 may be disposed proximate a first end 243 of the shaft 240.

The fixed portion 290 may also comprise a wire snap ring slot 296 formed within its bore 292. A snap ring 286 may be disposed around a second end 247 of the shaft 240 to stabilize the rotating portion 210 of the degradation assembly 200.

FIG. 3 is a cross-sectional diagram of another embodiment of the degradation assembly 300. The degradation assembly 300 may comprise a locking mechanism 360 adapted to attach the shaft 340 to the bolster 330, which shaft 340 can include a shank 350 coupled to a threaded attachment 344. The locking mechanism 360 may comprise a locking shaft 366 intermediate a locking head 362 and a threaded base end 368. The locking head 362 may comprise a complementary geometry relative to a geometry of the cavity 332 of the bolster 330. The bolster cavity 332 may include an O-ring 382 that may aid in wear resistance. The threaded base end 368 of the locking shaft 366 may be threadedly attached to a locking nut 348 located within a shank cavity 356 formed into the base of the shank 350.

The base end 347 of the shaft 340 can include a threaded attachment 344 that is threaded into the base portion of the shank cavity 356 and about a spring 346, which spring 346 may add to the life of the degradation assembly by minimizing axial wobble in the rotating portion. The base end 347 of the shaft 340 may also comprise a snap ring 386 disposed around the threaded attachment 344 and adapted to connect the shaft 340 of the rotating portion 201 to the non-rotating sleeve 370 of the fixed portion 390 of the degradation assembly 300.

The degradation assembly 300 may also comprise a fluid passage 304 formed within the shaft 340 and/or shank 350 of the rotating portion 310. The fluid passage 304 may run through the shaft 340 and/or shank 350 and into surrounding portions of the degradation assembly 300. Thus, a fluid may be passed through a port in the threaded attachment 344, into the fluid passage 304 formed into the shaft 340 and/or shank 350, and into the degradation assembly 300, for added wear resistance and lubrication.

FIG. 4 is a cross-sectional diagram of another embodiment of a degradation assembly 400. The fixed portion 490 of the degradation assembly 400 may comprise a snap ring 486 disposed at the second end 418 of the rotating portion 410, and which snap ring is adapted to secure the rotating portion 410 to the fixed portion 490. The rotating portion 410 may rotate around the snap ring 486. A plurality of springs 446 may be disposed around the second end 418 of the rotating portion 410 as well. It is believed that the spring 446 may add to the life of the degradation assembly 400 by minimizing axial movement in the degradation assembly. A second spring 488 may be a retaining spring. The second spring 488 may stabilize the rotating portion 410.

FIG. 5 is a cross-sectional diagram of another embodiment of a degradation assembly 500. The fixed portion 590 of the degradation assembly 500 may comprise a threadform 598 adapted to be threadedly attached to a holder 506. A first end 593 of the fixed portion 590 may comprise a hexagonal geometry. The fixed portion 590 may comprise a diameter less than a diameter of the rotating portion 510.

FIG. 6 is a cross-sectional diagram of another embodiment of a degradation assembly 600. The degradation assembly 600 may comprise a rotating portion 610 that includes a carbide bolster 630 intermediate a tip 220 and a shaft 640. The shaft 640 may comprise a taper 645 adapted to receive a taper 635 of the carbide bolster 630. The tapers may aid in wear resistance to the assembly during degradation of a material. The tapers 635, 645 may be able to withstand greater forces at more angles than if there were no taper. The bolster 630 may be brazed 639 along its taper to the shaft 640. In some embodiments, the bolster is only brazed along the taper.

FIG. 7 is a cross-sectional diagram of another embodiment of a degradation assembly 700. The degradation assembly 700 may comprise a rotating portion 710 that includes a carbide bolster 730 intermediate a tip 720 and a shaft 740. The shaft 740 may comprise a taper 745 adapted to receive a taper 735 of the carbide bolster 730. The bolster 730 may be brazed 739 along a base portion 732 to a face 742 of the rotating portion. This may provide the advantage of minimizing the surface areas that are brazed since the applicants have found that a larger surface area may compromise the integrity of the braze.

FIG. 8 shows another embodiment of the degradation assembly 800 in which the bolster 830 may be brazed 839 to the steel body of a shaft 840 along a taper 835 of the base of the bolster. A cavity 832 in the bolster 830 reduces the surface area of the braze. In some embodiments, voids may be formed along the taper 835 to reduce surface area of the braze.

FIG. 9 discloses another embodiment of the degradation assembly 900 with flats 914 incorporated on the rotating portion 910. These flats may be use to apply torque to the rotating portion with a tool such as a wrench. In some embodiments, the degradation assembly is used for a period of time and then manually rotated so that wear occurs more evenly.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.

Claims

1. A degradation assembly comprising: a rotating portion including: a carbide bolster having a base end and a working end;a wear resistant tip bonded to the working end; anda shaft having a first end and a second end spaced away from the first end, the first end being attached to the base end;a fixed portion adapted for rigid connection to a driving mechanism, the fixed portion having a bore formed therein, the bore being sized and shaped to receive the shaft of the rotating portion, the bore having an O-ring slot formed therein; andan O-ring located within the O-ring slot and contacting the shaft, the O-ring being at least 15 percent compressed by the shaft such that the O-ring substantially resists rotation of the shaft relative to the bore.

2. The degradation assembly of claim 1, wherein the shaft comprises: a shank, the shank being attached to the base end, anda sleeve, wherein the shank is a disposed within the sleeve.

3. The assembly of claim 1, further comprising a tapered receptacle formed in the first end of the shaft, the tapered receptacle being adapted to receive therein a tapered base end of the carbide bolster.

4. The degradation assembly of claim 3, wherein the base end of the bolster comprises a taper complementary with the tapered receptacle.

5. The degradation assembly of claim 1, wherein the shaft is between the bolster and the fixed portion.

6. The degradation assembly of claim 1, further comprising a locking mechanism, the locking mechanism being adapted to attach the shaft to the base end of the carbide bolster.

7. The degradation assembly of claim 6, wherein the locking mechanism is axially disposed within both the bore of the fixed portion and the shaft of the rotating portion.

8. The degradation assembly of claim 6, further comprising a cavity formed in the based end of the bolster, and wherein the locking mechanism is adapted to interlock with the cavity.

9. The degradation assembly of claim 8, wherein the locking mechanism comprises a threadform proximate the second end of the shaft, the threadform being engagable with a threaded locking device.

10. The degradation assembly of claim 8, wherein the locking mechanism comprises a protruding member proximate the first end of the shaft, the protruding member being mechanically engagable with an internal lip of the cavity.

11. The degradation assembly of claim 1, wherein the wear resistant tip comprises: a carbide substrate; anda diamond layer, the diamond layer being bonded to the carbide substrate, and the carbide substrate having an axial thickness that is less than an axial thickness of the diamond layer as measured along a centerline axis of the rotating portion.

12. A degradation assembly for use with a driving mechanism, said degradation assembly comprising: a first portion including: a carbide bolster having a base end and a working end,a wear resistant tip bonded to said working end, anda shaft having a first end and a second end spaced apart from said first end, said first end being attached to said base end, said second end having an outside surface;a second portion connectable to a driving mechanism, said second portion having a bore formed therein, and said bore being sized and shaped to receive said shaft of said first portion, said bore having an inside surface;an O-ring groove, said O-ring groove being formed within one of said outside surface of said shaft and said inside surface of said bore; andan O-ring, said O-ring being located within said O-ring groove, said O-ring being adapted to contact the other of said outside surface of said shaft and said inside surface of said bore, and said O-ring being adapted to impede rotation of said shaft and said bore relative to each other.

13. The degradation assembly of claim 12, wherein said O-ring is at least 15 percent compressed between said outside surface of said shaft and said inside surface of said bore.

14. The degradation assembly of claim 12, further comprising: said second portion being adapted for rigid connection to said driving mechanism;said O-ring groove being formed into said inside surface of said bore; andsaid O-ring being positionable within said O-ring groove and adapted to contact said outside surface of said rotating shaft.

15. The degradation assembly of claim 12, further comprising a tapered receptacle formed in said first end of said shaft, said tapered receptacle being adapted to receive therein a tapered base end of said carbide bolster.

16. The degradation assembly of claim 12, wherein said shaft further comprises: a shank, said shank being attached to said base end; anda sleeve, said sleeve being disposed about said shank.

17. The degradation assembly of claim 16, further comprising a locking mechanism, said locking mechanism being configured to attach said shank to said base end.

18. The degradation assembly of claim 17, wherein said locking mechanism is axially disposed within each of said shank and said bore.

19. The degradation assembly of claim 16, wherein said resistance device is adapted to contact an outside surface of said sleeve.

20. The degradation assembly of claim 12, wherein said second portion comprises: a fixed portion, said fixed portion connectable to said driving mechanism; anda sleeve, said sleeve installed within said fixed portion, said sleeve including said bore.

21. The degradation assembly of claim 20, wherein said shaft comprises a shank, said shank being attached to said base end by a locking mechanism, and said shank being rotatably receivable within said bore of said sleeve.

22. A degradation assembly for use with a driving mechanism, said degradation assembly comprising: a carbide bolster having a base end and a working end;a wear resistant tip bonded to said working end;a shaft having a first end and a second end spaced from said first end, said first end being attached to said base end;a support portion connectable to a driving mechanism, said support portion having a bore formed therein, said bore being sized and shaped to receive said shaft and to support said shaft in rotatable connection with said support portion;an O-ring groove, said O-ring groove being formed within one of an outside surface of said shaft and an inside surface of said bore; andan O-ring, said O-ring being located within said O-ring groove, said O-ring being adapted to contact the other of said outside surface of said shaft and said inside surface of said bore, and said O-ring being at least 15 percent compressed to impede rotation of said shaft and said bore relative to each other.

23. The degradation assembly of claim 22, wherein said resistance means comprises: an O-ring groove, said O-ring groove being formed into an inside surface of said bore; andan O-ring, said O-ring positionable within said O-ring groove, said O-ring being adapted to contact an outside surface of said shaft.

24. The degradation assembly of claim 22, further comprising a tapered receptacle formed in said first end of said shaft, said tapered receptacle being adapted to receive therein a tapered base end of said carbide bolster.

25. The degradation assembly of claim 22, wherein said shaft comprises: a shank, said shank being attached to said base end; anda sleeve, said sleeve being disposed about said shank.

26. The degradation assembly of claim 25, further comprising a locking mechanism, said locking mechanism being configured to attach said shank to said base end.

27. The degradation assembly of claim 26, wherein said locking mechanism is axially disposed within each of said shank and said bore.

28. The degradation assembly of claim 25, wherein said resistance means is adapted to contact an outside surface of said sleeve.

29. The degradation assembly of claim 22, wherein said support portion comprises: a fixed portion, said fixed portion connectable to said driving mechanism; anda sleeve, said sleeve installed within said fixed portion, said sleeve including said bore.

30. The degradation assembly of claim 29, wherein said shaft comprises a shank, said shank being attached to said base end by a locking mechanism, and said shank being rotatably receivable within said bore of said sleeve.