Patent Application
20130009446
The present invention relates generally to formation degradation machines and specifically to road milling and mining machines. A pick assembly is generally attached to drums, drills, or chains, which are configured to drive the pick assemblies into the formation with an impacting force that degrades the formation's surface.
U.S. Patent Application No. 2005/0056437 to Gaudielle et al., which is herein incorporated for all that it contains, discloses a pick that comprises a handle and a pick head coupled to the handle at an acute angle thereto. The pick head has a top, and first and second side edges, which extend away from the top and meet at a bottom point. The pick head includes at least one tab extending from the pick head top toward the handle. The tab has a length sufficient to serve as a foot support and as a striking surface.
U.S. Pat. No. 7,401,863 to Hall et al., which is herein incorporated for all that it contains, discloses a pick that comprises a shank attached to a base of a steel body, a cemented metal carbide core press fit into the steel body opposite the shank, and an impact tip bonded to a first end of the core opposite the shank. The impact tip comprises a superhard material opposite the core, and the core comprises a second end and a largest diameter. A distance through the body from the shank to the second end of the core is less than the largest diameter of the core.
U.S. Pat. No. 7,338,135 to Hall et al., which is herein incorporated for all that it contains, discloses a degradation assembly that has an attack tool with a body and a shank, the body having a wear-resistant tip. The shank is disposed within a bore of a holder secured to a driving mechanism. The bore of the holder comprises an inner surface comprising a hardness greater than 58 HRC.
In one aspect of the present invention, a pick assembly comprises a body with a central axis that intersects a working end and a base end. The base end comprises a shank that is configured to be rotationally fixed within a block of a driving mechanism. The working end comprises a tip that is harder than the body and configured to degrade a formation. The body further comprises a streamlined side that is configured to reduce resistance resulting from a flow of aggregate as the tip degrades the formation. The streamlined side may be configured to reduce the pick assembly's drag through the degraded aggregate. The pick assembly also comprises a support side that is configured to support the tip.
The support side comprises a spine with a braze end that forms a bond interface with the tip and a bolstering end that is opposite the braze end. An external surface of the spine progressively advances towards the central axis at the braze end. The streamlined side comprises a bulge opposite the bolstering end of the spine. The bulge may be at least partially formed in a carbide portion of the body. At least one recess is formed between the bulge and the spine and is configured to direct the flow of aggregate around the pick assembly's body.
The recess may be configured to reduce surface contact that may occur between the assembly's body and the formation being degraded. The recess may comprise a steeper incline proximate the tip and a gradual incline proximate the bulge. The reduced contact between the pick assembly and loose aggregate may decrease friction, which will reduce the overall energy consumption. The reduced surface contact may further enable the aggregate to more easily flow past the pick assembly.
The body of the pick may further be configured to shield the support side of the pick from the formation being degraded. The external surface of the spine may comprise a curved geometry. The curved geometry may provide necessary support along the body to adequately support the tip while shielding the support side from the formation.
The assembly's body may comprise a carbide section and metal section that are bonded together. The carbide section may be bonded to the tip, which may comprise a carbide substrate and a superhard working surface. The superhard material may be sintered polycrystalline diamond. In some embodiments, the carbide substrate is brazed at a planar interface to the carbide section. In some embodiments, the pick assembly's base end may comprise a substantially circular geometry.
In some embodiments, the recess and spine may be formed in the carbide section of the body. The body may also comprise a steel portion that forms a proximal spine, at least one proximal recess, and a proximal bulge. The recesses may redirect the aggregate pathway to flow around the assembly's body with minimal resistance.
The body may comprise at least two recesses. Both recesses may be formed between the spine and a first and second side of the bulge. The recesses may be in close proximity to another near the bulge and diverge away from one another as they approach the support side.
Referring now to the figures,
The base end 202 may comprise a shank that is configured to be rotationally fixed within a block 208 of the rotary degradation drum 103 or other driving mechanism. The tip 203 may wear at a slower rate in comparison to the rest of the pick assembly 105 due to the tip material's wear resistant properties. In some embodiments, the tip may rotate.
A support side 205 may be configured to support the tip 203. The body 200 may be configured to shield the support side 205 from the formation.
The body 200 may also comprise a streamlined side 204 configured to reduce a resistance force that may result from a flow of aggregate as the tip 203 degrades the formation. The streamlined side 204 may be configured to improve the flow of degraded aggregate around the pick 105 by redirecting the flow of loose aggregate through recesses formed between a bulge 303 of the streamlined side 204 and an spine 300 of the support side 205.
The assembly 105 may comprise a carbide section and a metal section, such as a steel section. The carbide section may be bonded to the metal section at a braze joint. The carbide section may also be bonded to the pick assembly's tip 203.
The base end 202 may comprise a substantially circular geometry. The working end 201 may be significantly smaller than the base end 202, thereby, focusing the impact force just ahead of the tip 203.
An external surface of the spine 300 may progressively advance towards the central axis at the braze end 206. The progressive advancement may result in the working end 201 becoming substantially smaller than the base end.
The external surface of the spine 300 may comprise a curved geometry. The curved geometry may aid in shielding the support side 205 from the formation and in evenly distributing forces that are applied to the spine 300 throughout the degradation process.
The streamlined side 204 may comprise the bulge 303 proximate the bolstering end 207 of the spine 300. The bulge 303 may be at least partially formed in the carbide portion of the body 200. The bulge 303 may comprise a material with a high hardness rating to prevent erosion from occurring at the bulge 303. In some embodiments, the bulge 303 may be partially formed in the metal portion of the assembly 105. The bulge 303 may force loose aggregate into the recesses 304, 350 that are formed between the bulge 303 and the spine 300. These recesses 304, 350 may further direct the loose aggregate away from the pick assembly's body 200 along a low friction path that is designed to reduce drag.
In some embodiments, the recesses are formed in a carbide section. The recesses' geometry may reduce erosion on the pick body 200. The recesses 304, 350 may comprise a gradual curve near the bulge 303 and the curve may become steeper near the support side 205. The bulge 303 may, in effect, plow through loose aggregate forcing the aggregate into the recesses 304, 350 along the gradual curve. The entrance into the recesses 304, 350 may be narrower than the base of the pick body 200. Thus, the loose aggregate may be effectively directed into either recess 304, 350. Preferably, the recesses 304, 350 efficiently direct the aggregate away from the pick while keeping the aggregate away from the support side 205, which has the function of supporting the tip 203.
The geometry of the present invention may conserve the material of the pick assembly's body 200. In the current embodiment, the pick assembly 105 may be formed through a mold or another alternative manufacturing process.
The recesses 304, 350 may further be configured to prevent degraded aggregate buildup from occurring during the degradation process and specifically to prevent buildup from occurring proximate the tip 203. The recesses 304, 350 may provide an area or pathway for the degraded aggregate to flow through to clear up the formation 104 currently being degraded. The buildup prevention may improve a pick's ability to degrade through the formation 104 by reducing the aggregate that the pick assembly 105 must go through to reach the formation 104.
The recesses 304, 350 may be configured to funnel aggregate around the body 200 of the pick 105, directing the aggregate away from the pick's body 200. By directing the aggregate away from the pick's body 200, an impact between the aggregate and body 200 may decrease in magnitude.
At least one proximal recess 705, 706 may be disposed away from the distal recesses 304, 350 along the length of the pick assembly and may be formed in the metal portion of the assembly 105. The proximal recesses 705, 706 may divert the degraded aggregate to either side of the pick assembly 105 and away from the body 200 of the pick 105. The proximal recesses 705, 706 may further direct the loose aggregate along a low friction path designed to reduce the drag.
Additionally, the metal portion may form a proximal spine 707 near the proximal recesses 705, 706 and spaced away from the distal spine 300. The proximal spine 707 may provide additional support to the pick assembly 105. The metal portion may also form a proximal bulge 708 proximate the proximal recesses 705, 706 and opposite the proximal spine 707. The proximal bulge 708 may redirect the loose aggregate toward the streamlined side 204 and into the proximal recesses 706, which may then direct the aggregate to a side of the body 200 that is away from the proximal spine 707.
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.
