Patent Description:
The present disclosure relates to mining and excavation machines, and in particular to a cutting device for a mining or excavation machine. <CIT> discloses an underground mining machine.

Hard rock mining and excavation typically requires imparting large energy on a portion of a rock face in order to induce fracturing of the rock. One conventional technique includes operating a cutting head having multiple mining picks. Due to the hardness of the rock, the picks must be replaced frequently, resulting in extensive down time of the machine and mining operation. Another technique includes drilling multiple holes into a rock face, inserting explosive devices into the holes, and detonating the devices. The explosive forces fracture the rock, and the rock remains are then removed and the rock face is prepared for another drilling operation. This technique is time-consuming and exposes operators to significant risk of injury due to the use of explosives and the weakening of the surrounding rock structure. Yet another technique utilizes roller cutting element(s) that rolls or rotates about an axis that is parallel to the rock face, imparting large forces onto the rock to cause fracturing.

In one aspect, a cutting assembly for a rock excavation machine having a frame is disclosed in claim <NUM>.

Other aspects will become apparent by consideration of the detailed description and accompanying drawings.

Before any embodiments are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The use of "including," "comprising" or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "mounted," "connected" and "coupled" are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings, and can include electrical or hydraulic connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using any known means including direct connections, wireless connections, etc..

In addition, it should be understood that embodiments of the invention may include hardware, software, and electronic components or modules that, for purposes of discussion, may be illustrated and described as if the majority of the components were implemented solely in hardware. However, one of ordinary skill in the art, and based on a reading of this detailed description, would recognize that, in at least one embodiment, aspects of the invention may be implemented in software (for example, stored on non-transitory computer-readable medium) executable by one or more processing units, such as a microprocessor, an application specific integrated circuits ("ASICs"), or another electronic device. As such, it should be noted that a plurality of hardware and software based devices, as well as a plurality of different structural components may be utilized to implement the invention. For example, "controllers" described in the specification may include one or more electronic processors or processing units, one or more computer-readable medium modules, one or more input/output interfaces, and various connections (for example, a system bus) connecting the components.

<FIG> and <FIG> illustrate an excavation machine or mining machine <NUM> including a chassis <NUM>, a boom <NUM>, a cutting head or cutting device <NUM> for engaging a rock face <NUM> (<FIG>), and a material gathering head or gathering device <NUM>. In the illustrated embodiment, the chassis <NUM> is supported on a crawler mechanism <NUM> for movement relative to a floor (not shown). The gathering device <NUM> includes a deck <NUM> and rotating arms <NUM>. As the machine <NUM> advances, the cut material is urged onto the deck <NUM>, and the rotating arms <NUM> move the cut material onto a conveyor <NUM> (<FIG>) for transporting the material to a rear end of the machine <NUM>. In other embodiments, the arms <NUM> may slide or wipe across a portion of the deck <NUM> (rather than rotating) to direct cut material onto the conveyor <NUM>. Furthermore, in some embodiments, the gathering device <NUM> may also include a pair of articulated arms <NUM>, each of which supports a bucket <NUM>. The articulated arms <NUM> and buckets <NUM> may remove material from an area in front of the machine <NUM> and may direct the material onto the deck <NUM>.

As shown in <FIG>, the boom <NUM> supports the cutting device <NUM>. The boom <NUM> includes a first portion or base portion <NUM> and a second portion or wrist portion <NUM> supporting the cutting device <NUM>. The base portion <NUM> includes a first end <NUM> coupled to the chassis <NUM> (<FIG>) and a second end <NUM>, and the base portion <NUM> defines a base axis <NUM> extending between the first end <NUM> and the second end <NUM>. In one embodiment, the first end <NUM> is pivotable relative to the chassis <NUM> about a transverse axis <NUM> oriented perpendicular to the base axis <NUM>. The transverse axis <NUM> may be offset from the base axis <NUM> such that the transverse axis <NUM> and base axis <NUM> do not intersect. In the illustrated embodiment, the boom <NUM> is formed as a first structure <NUM> proximate the first end <NUM> and a second structure <NUM> proximate the second end <NUM>. The first structure <NUM> is pivotable and includes an opening <NUM> receiving the second structure <NUM> in an extendable or telescoping manner. The first structure <NUM> is pivotable about the transverse axis <NUM> and may also be pivoted laterally about a vertical axis or slew axis <NUM> (<FIG>) (e.g., by rotation of a turntable coupling).

The wrist portion <NUM> is coupled to the movable structure <NUM> and supported relative to the base portion <NUM>. The wrist portion <NUM> may move or telescope with the second end <NUM> of the base portion <NUM>, thereby selectively extending and retracting the wrist portion <NUM> in a direction parallel to the base axis <NUM>. In the illustrated embodiment, the second end <NUM> is extended and retracted by operation of one or more fluid actuators <NUM> (e.g., hydraulic cylinders - <FIG>). The wrist portion <NUM> includes a first end <NUM> and a second end <NUM> and defines a wrist axis <NUM>. In some embodiments, when the wrist portion <NUM> is in a rest position, the wrist axis <NUM> may be oriented substantially parallel to the base axis <NUM>. The first end <NUM> of the wrist portion <NUM> is supported by the second end <NUM> of the base portion <NUM>. The cutting device <NUM> is coupled to the second end <NUM> of the wrist portion <NUM>.

Referring to <FIG>, the cutting device <NUM> includes a cutting bit or cutting disc <NUM> having a peripheral edge <NUM>, and a plurality of cutting bits <NUM> (<FIG>) positioned along the peripheral edge <NUM>. The peripheral edge <NUM> defines a cutting plane <NUM>, and the cutting disc <NUM> rotates about a cutter axis <NUM> (<FIG>).

As shown in <FIG>, in the illustrated embodiment, the cutting device <NUM> further includes a housing <NUM>, an excitation element <NUM>, and a shaft <NUM> removably coupled (e.g., by fasteners) to the excitation element <NUM>. The cutting disc <NUM> is coupled (e.g., via fasteners) to a carrier <NUM> that is supported on an end of the shaft <NUM> for rotation (e.g., by roller bearings) about the cutter axis <NUM>. In the illustrated embodiment, the cutting disc <NUM> engages the carrier <NUM> along an inclined surface <NUM> forming an acute angle relative to the cutting plane <NUM>. Defined another way, the cutting disc <NUM> abuts a surface <NUM> tapering inwardly toward the cutter axis <NUM> in a direction oriented away from the housing <NUM>. In some embodiments, the cutting disc <NUM> is supported for free rotation relative to the housing <NUM> (i.e., the cutting disc <NUM> is neither prevented from rotating nor positively driven to rotate except by induced oscillation).

In the illustrated embodiment, the end of the shaft <NUM> is formed as a stub or cantilevered shaft generally extending parallel to the cutter axis <NUM>. The excitation element <NUM> may include an exciter shaft <NUM> and an eccentric mass <NUM> secured to the exciter shaft <NUM> for rotation with the exciter shaft <NUM>. The exciter shaft <NUM> is driven by a motor <NUM> and is supported for rotation (e.g., by roller bearings). The rotation of the eccentric mass <NUM> induces an eccentric oscillation in the shaft <NUM>, thereby inducing oscillation of the cutting disc <NUM>. In some embodiments, the structure of the cutting device <NUM> and excitation element <NUM> may be similar to the cutter head and excitation element described in <CIT>, the entire contents of which are hereby incorporated by reference. In other embodiments, the cutting device <NUM> and excitation element <NUM> may be similar to the exciter member and cutting bit described in <CIT>, the entire contents of which are hereby incorporated by reference.

Referring again to <FIG>, in the illustrated embodiment, the cutter axis <NUM> is oriented at an angle <NUM> relative to a tangent of the rock face <NUM> at a contact point with the cutting disc <NUM>. In some embodiments, the angle <NUM> is between approximately <NUM> degrees and approximately <NUM> degrees. In some embodiments, the angle <NUM> is between approximately <NUM> degree and approximately <NUM> degrees. In some embodiments, the angle <NUM> is between approximately <NUM> degrees and approximately <NUM> degrees. In some embodiments, the angle <NUM> is approximately <NUM> degrees.

The cutting device <NUM> engages the rock face <NUM> by undercutting the rock face <NUM>. That is, a leading edge of the cutting disc <NUM> engages the rock face <NUM> such that the cutting disc <NUM> (e.g., the cutting plane <NUM>) forms a low or small angle relative to the rock face <NUM> and traverses across a length of the rock face <NUM> in a cutting direction <NUM>. Orienting the cutting disc <NUM> at an angle provides clearance between the rock face <NUM> and a trailing edge of the cutting disc <NUM> (i.e., a portion of the edge that is positioned behind the leading edge with respect to the cutting direction <NUM>).

Referring to <FIG>, the wrist portion <NUM> includes a universal joint or U-joint <NUM> coupling the first member <NUM> and the second member <NUM>. In particular, the first member <NUM> includes a pair of parallel first lugs <NUM> and the second member <NUM> includes a pair of parallel second lugs <NUM>. A first shaft <NUM> is positioned between the first lugs <NUM> and a second shaft <NUM> is positioned between the second lugs <NUM> and is coupled to the first shaft <NUM>. In some embodiments, the second shaft <NUM> is rigidly coupled to the first shaft <NUM>. In the illustrated embodiment, the first shaft <NUM> and second shaft <NUM> are positioned in a support member <NUM> and are supported for rotation relative to the lugs <NUM>, <NUM> by bearings <NUM>, <NUM>, respectively. The first shaft <NUM> defines a first axis <NUM> that is substantially perpendicular to the wrist axis <NUM>, and the second shaft <NUM> defines a second axis <NUM>. In the illustrated embodiment, the second axis <NUM> is substantially perpendicular to the cutter axis <NUM>. The first axis <NUM> and the second axis <NUM> are oriented perpendicular to each other. The universal joint <NUM> allows the second member <NUM> to pivot relative to the first member <NUM> about the first axis <NUM> and the second axis <NUM>. Other aspects of universal joints are understood by a person of ordinary skill in the art and are not discussed in further detail. Among other things, the incorporation of a universal joint permits the cutting device <NUM> to precess about the axes of the universal joint, and the joint is capable of transferring shear and torque loads.

The wrist portion <NUM> further includes a suspension system for controlling movement of the second member <NUM> relative to the first member <NUM>. In the illustrated embodiment, the suspension system includes multiple fluid cylinders <NUM> (e.g., hydraulic cylinders). The fluid cylinders <NUM> maintain a desired offset angle between the first member <NUM> and the second member <NUM>. The fluid cylinders <NUM> act similar to springs and counteract the reaction forces exerted on the cutting device <NUM> by the rock face <NUM>.

In the illustrated embodiment, the suspension system includes four fluid cylinders <NUM> spaced apart from one another about the wrist axis <NUM> by an angular interval of approximately ninety degrees. The cylinders <NUM> extend in a direction that is generally parallel to the wrist axis <NUM>, but the cylinders <NUM> are positioned proximate the end of each of the first shaft <NUM> and the second shaft <NUM>. Each fluid cylinders <NUM> includes a first end coupled to the first member <NUM> and a second end coupled to the second member <NUM>. The ends of each cylinder <NUM> may be connected to the first member <NUM> and the second member <NUM> by spherical couplings to permit pivoting movement. The suspension system transfers the cutting force as a moment across the universal joint <NUM>, and controls the stiffness between the wrist portion <NUM> and the base portion <NUM>.

In other embodiments, the suspension system may include fewer or more fluid actuators <NUM>. The fluid actuators <NUM> may be positioned in a different configuration between the first member <NUM> and the second member <NUM> (e.g., see <FIG>, in which the hydraulic cylinders <NUM> are offset from the axes of the shafts <NUM>, <NUM>; stated another way, each cylinder <NUM> may extend between a corner of the first member <NUM> and a corresponding corner of the second member <NUM>). In still other embodiments, the suspension system may incorporate one or more mechanical spring element(s), either instead of or in addition to the fluid cylinders <NUM>.

<FIG> shows another embodiment of the boom <NUM> including a wrist portion <NUM> which does not however fall under the scope of the claims. For brevity, only differences are discussed, and similar features are identified with similar reference numbers, plus <NUM>. The wrist portion <NUM> may include a first member <NUM> that pivots about a first pivot pin <NUM> and a second member <NUM> that pivots about a second pivot pin <NUM> that is offset from the first pivot pin <NUM>. The first member <NUM> and the second member <NUM> may pivot about perpendicular, offset axes. The first member <NUM> forms a first end of the wrist portion <NUM>. The second member <NUM> forms the second end <NUM> of the wrist portion <NUM> and supports the cutting device <NUM>.

The first member <NUM> is coupled to the base portion <NUM> by the first pivot pin <NUM>, and the second member <NUM> is coupled to the first member <NUM> by the second pivot pin <NUM>. In the illustrated embodiment, the first pivot pin <NUM> provides a first pivot axis <NUM> oriented perpendicular to the base axis <NUM> and permits the first member <NUM> to pivot relative to the base portion <NUM> in a plane containing axis <NUM>. The second pivot pin <NUM> provides a second pivot axis <NUM> oriented transverse to the base axis <NUM> and perpendicular to the first pivot axis <NUM>, permitting the second member <NUM> to pivot relative to the first member <NUM> in a vertical plane. The first member <NUM> is pivoted about the first pivot axis <NUM> by actuation of a first actuator <NUM>, and the second member <NUM> is pivoted about the second pivot axis <NUM> by actuation of a second actuator <NUM>.

<FIG> and <FIG> shows another embodiment of the boom <NUM> including a wrist portion <NUM> supported by multiple articulating boom portions, which does not however fall under the scope of the claims. In particular, a base portion <NUM> of the boom <NUM> includes a first member or first structure <NUM> and a second member or second structure <NUM> pivotably coupled to the first structure <NUM>. In the illustrated embodiment, the first structure <NUM> is supported on a slew coupling <NUM> for pivoting the boom <NUM> in a lateral plane about a slew axis <NUM>. The first structure <NUM> is pivotable relative to the slew coupling <NUM> about a first axis <NUM> oriented transverse to the slew axis <NUM>, and the second structure <NUM> is pivotable relative to the first structure <NUM> about a second axis <NUM> oriented parallel to the first axis <NUM>. The slew coupling <NUM> may be driven to pivot by actuators (e.g., hydraulic cylinders - not shown). The first structure <NUM> is driven to pivot about the first axis <NUM> by first actuators <NUM>, and the second structure <NUM> is driven to pivot about the second axis <NUM> by second actuators <NUM>. The first axis <NUM> and second axis <NUM> both extend in a transverse orientation, thereby providing two independently articulating luff portions to provide significant versatility for pivoting the cutting device in a vertical plane. In other embodiments, the first structure and second structure may pivot in a different manner. The wrist portion <NUM> is secured to an end of the second structure <NUM> distal from the first structure <NUM>, and the cutting device <NUM> is supported by the wrist portion <NUM>.

Referring now to <FIG>, the first member <NUM> of the wrist portion <NUM> is coupled to the movable structure <NUM> of the base portion <NUM>. In the illustrated embodiment, a fluid manifold <NUM> (e.g., a sandwich manifold) is positioned between the movable structure <NUM> and the first member <NUM>, and a linear actuator <NUM> (e.g., a hydraulic piston-cylinder device) is positioned within the base portion <NUM>. One end (e.g., a rod end) of the linear actuator <NUM> may be connected to the first structure <NUM>, and another end (e.g., a cylinder end) of the actuator <NUM> may be connected to the manifold <NUM>. The linear actuator <NUM> may have cylinder chambers in fluid communication with the manifold <NUM>. Extension of the linear actuator <NUM> causes extension of the movable structure <NUM> in a direction parallel to the boom axis <NUM>, and retraction of the linear actuator <NUM> causes retraction of the movable structure <NUM> in a direction parallel to the boom axis <NUM>. In the illustrated embodiment, a sensor <NUM> is coupled between an outer surface of the first structure <NUM> and the manifold <NUM>. The sensor <NUM> may include a transducer for measuring the stroke or position of the linear actuator <NUM> and the movable structure <NUM>.

As best shown in <FIG>, the movable structure <NUM> is supported relative to the first structure <NUM> by bearing assemblies <NUM>. In the illustrated embodiment, eight bearing assemblies <NUM> are located in a common plane normal to the base axis <NUM>, with two bearing assemblies <NUM> abutting each of the four sides of the movable structure <NUM>. An additional set of eight bearing assemblies may be positioned in a similar manner in a second plane normal to the base axis <NUM> and offset from the plane illustrated in <FIG>. In other embodiments, the base portion <NUM> may include fewer or more bearing assemblies <NUM>, and the bearing assemblies <NUM> may be positioned in multiple planes along the length of the base axis <NUM>. The bearing assemblies <NUM> may be positioned in a different manner.

As shown in <FIG>, each bearing assembly <NUM> includes a main support <NUM> secured to the base portion <NUM> and a pad <NUM> abutting a surface of the movable structure <NUM>. In addition a spherical bearing member <NUM> is coupled to the main support <NUM> to permit pivoting movement of the pad <NUM> relative to the main support <NUM>. The pad <NUM> includes one or more pockets or chambers or galleries <NUM> formed in a surface of the pad <NUM> adjacent the movable structure <NUM>. The main support <NUM> includes a port <NUM> and a passage <NUM> providing communication between the port <NUM> and galleries <NUM>. The port <NUM> may receive a lubricant (e.g. grease) through a manual feed or an automatic lubrication system, and the lubricant may be transferred to the galleries <NUM> to lubricate the interface between the pad <NUM> and the movable structure <NUM>. In addition, in the illustrated embodiment, a hard, low-friction bearing surface <NUM> is secured to an outer surface of the movable structure <NUM>. The bearing surface <NUM> may be removably secured to the movable structure <NUM> (e.g., by fasteners) or attached by fusion (e.g., welding). The bearing assemblies <NUM> provide a low-friction interface and are capable of transmitting large forces caused by the cutting operation.

Claim 1:
A cutting assembly for a rock excavation machine (<NUM>) including a frame, the cutting assembly comprising:
a boom (<NUM>) including a first portion (<NUM>) and a second portion (<NUM>), the first portion (<NUM>) configured to be supported by the frame, the second portion (<NUM>) pivotably coupled to the first portion (<NUM>) by a universal joint, the first portion (<NUM>) including a base (<NUM>) and a moveable structure (<NUM>), the base (<NUM>) extending along a longitudinal base axis (<NUM>), the moveable structure (<NUM>) coupled to the second portion (<NUM>) by the universal joint (<NUM>), the moveable structure (<NUM>) supported for movement relative to the base (<NUM>) in a direction parallel to the longitudinal base axis (<NUM>); and
a cutting device (<NUM>) supported by the second portion of the boom (<NUM>).