In the trenching industry, earth may be degraded using picks or teeth to break up minerals and rocks. Picks are generally attached to trenching booms or wheels and are used for making trenches in the earth for installing pipes and utility lines and digging foundations for homes or other buildings.
Some of the trenching machines of the prior art are disclosed in U.S. Pat. Nos. 7,150,131; 6,854,201; 6,457,267, and 6,341,823.
In one aspect of the invention a trenching machine for degrading natural and man-made formations has a plurality of picks with wheels rotationally supported by housings exteriorly mounted to a trenching boom or wheel. The roller assemblies have a plurality of pointed inserts radially arranged along an outer diameter of the wheel. The inserts may have a tip adapted to impact the formation.
The tip of the pointed inserts may comprise a superhard material selected from the group consisting of cubic boron nitride, diamond, diamond like material, or combinations thereof. In some embodiments, the tip comprises a carbide substrate bonded to the superhard material. The superhard material may be at least 0.100 inches thick, and may have a volume of 3 to 20 percent metal binder concentration. The tip may also comprise a 0.05 to 0.20 inch apex radius. The tip may be brazed to a carbide core which is press fit into a pocket formed in the wheel.
The pointed inserts may be radially positioned about the wheel which rotates about an axis causing the pointed inserts to rotationally engage the surface. The rotation of the pointed inserts is believed to lessen the drag that would otherwise occur on the pointed inserts thus, extending the life of the pointed inserts. The rotation effect is also believed to degrade the formation in larger chucks than dragging the tip against the formation. The cores may be press fit into pockets of the wheel. In other embodiments, the cores are brazed to the outer surface of the wheel or they are brazed or otherwise bonded into pockets formed in the wheel. In some embodiments the wheels are made of metal, steel, stainless steel, or hardened steel. In some embodiments of the invention the wheel and housing will be protected with a wear resistant material. Carbide buttons may be attached to the wheel, housing, or other components of the rolling assemblies to prevent wear.
The trenching machine may have a dampening element adapted to vibrationally insulate itself from the chain driven assembly. The dampening element may comprise a shock absorber, an elastic material, or a combination thereof.
In another aspect of the invention, a method comprising the steps of providing a plurality of roller assemblies comprising wheels rotationally supported by housings exteriorly mounted to a trenching boom or wheel. The wheels of the roller assembly comprise a plurality of pointed inserts radially arranged along the wheel's outer diameter. Another step involved positioning the trenching boom or wheel adjacent the formation; and another step involves degrading the formation with the inserts by activating the trenching boom or wheel.
a is a perspective diagram of another embodiment of a roller assembly.
Force is applied in the direction of the arrow 250 loading the weight of the boom on the pointed inserts 203. The pointed inserts 203 engage the surface at the impact tip 204, which is optimized for the wear life of the pick. Wear life is improved because the rotating motion reduces the effects of drag and wear on the pointed inserts 203. The housing 205, the wheel 202, and the pointed inserts 203 may comprise or be coated by a hard material to prevent wear. Carbide buttons may be attached to the housing, wheel, or other components of the rolling assembly by a press fit or they may be bonded.
The impact tips may comprise a super hard material which may comprise diamond, polycrystalline diamond with a binder concentration of 1 to 40 weight percent, cubic boron nitride, refractory metal bonded diamond, silicon bonded diamond, layered diamond, infiltrated diamond, thermally stable diamond, natural diamond, vapor deposited diamond, physically deposited diamond, diamond impregnated matrix, diamond impregnated carbide, monolithic diamond, polished diamond, course diamond, fine diamond, nonmetal catalyzed diamond, cemented metal carbide, chromium, titanium, aluminum, tungsten, or combinations thereof. The super hard material may be a polycrystalline structure with an average grain size of 10 to 100 microns. In some embodiment, a hard or superhard material may be applied to the roller assembly 101 and/or a paddle 201 to reduce wear.
A paddle 201 may be positioned behind the roller assembly and be adapted to remove loose fragments generated from the trenching process. In the embodiment of
The paddle 201 comprises a wear resistant distal end 503 that runs along the ground. A hard material that may be incorporated in the distal end may be carbide, cubic boron nitride, diamond, diamond like material, or combinations thereof. The paddle is flexibly attached to the chain and is designed to remove the loose unconsolidated portions of the formation while following the profile of the consolidation portions of the formation 104 such as large rocks 504. The paddle 201 comprises a spring mechanism 210 adapted to allow the distal end of the paddle to follow along the profile of the unbroken formation, while pushing the loose cuttings out of the trench. This spring mechanism 210 may comprise a coil spring, a compression spring, a tension spring, Belleville spring, wave spring, elastomeric material, gas spring, or combinations thereof. The spring mechanism may generate an axial load or it may generate an angular load as shown in the embodiment of
Referring now to
a discloses a roller assembly comprising a wheel with a plurality of canted inserts. By canting the inserts, each insert may engage the formation at a different location in the formation, which is believed to increase the rate of degradation of the formation. The inserts may be canted at any angle; in some embodiments, the inserts are canted at 2 to 10 degrees. In the embodiment of
In other embodiments, the housing is skewed which may offset the wheel such that the inserts break the formation in compression and shear. The housing may be skewed at an angle of 2 to 10 degrees. In some embodiment of the present invention, roller assemblies mounted to the chain may be used in combination with picks mounted to the chain.
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.
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Number | Date | Country | |
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20080282584 A1 | Nov 2008 | US |