Patent Description:
The present disclosure relates to underground mining machines. In particular, the present disclosure relates to a mining machine including multiple cutter heads, in particular, a first cutter head and a second cutter head.

Hard rock excavation typically requires imparting large energy on a portion of a rock face in order to induce fracturing of the rock. One conventional hard rock mining technique includes operating a cutter head having multiple mining picks. Due to the hardness of the rock, this method is often impractical because the picks must be replaced frequently, resulting in extensive down time of the machine. Another technique includes drilling multiple holes into a rock face and inserting an explosive device into the holes. 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, but this technique requires imparting large forces onto the rock to cause fracturing. The document <CIT> shows a machine used for excavating. The machine has a rotatable head, and cutting arms mounted on the head for rotation therewith, extending in the direction of excavation. At least one cutting arm is radially pivotable. The angular position of the head is continuously measured and output signals from these measurements are processed by a computer which controls the angular positions of the head and the arms. According to the present invention, a mining machine as defined by the features of claim <NUM> is provided. Further advantageous features of the invention e.g. are defined in the dependent claims.

In one aspect, a mining machine includes a frame, a boom supported for pivoting movement relative to the frame, and a cutter head pivotably coupled to the boom. The cutter head includes a housing, a cutter shaft coupled to the housing, a cutting disc, and an excitation mechanism. The cutter shaft includes a first end, a second end, a first portion positioned adjacent the first end, and a second portion positioned adjacent the second end. The second portion extends parallel to a cutter axis. The cutting disc is coupled to the second portion of the cutter shaft and is supported for free rotation relative to the cutter shaft about the cutter axis. The cutting disc includes a plurality of cutting bits defining a cutting edge. The excitation mechanism includes an exciter shaft and a mass eccentrically coupled to the cutter shaft. The exciter shaft is driven for rotation relative to the cutter shaft about an exciter axis. The excitation mechanism is coupled to the first portion of the cutter shaft. Rotation of the exciter shaft induces oscillating movement of the second portion of the cutter shaft and the cutting disc.

In another aspect, a mining machine includes a frame, a first boom supported for pivoting movement relative to the frame, a second boom supported for pivoting movement relative to the frame, a first cutter head pivotably coupled to the first boom, and a second cutter head pivotably coupled to the second boom. The second boom is movable independent of the first boom. The first cutter head is movable through a first range of movement and includes a first cutter shaft, a first cutting disc, and a first excitation mechanism. The first cutting disc is supported for free rotation relative to the first cutter shaft about a first cutter axis. The first cutting disc includes a plurality of first cutting bits defining a first cutting edge. The first excitation mechanism includes a first exciter shaft and a first mass eccentrically coupled to the first cutter shaft. Rotation of the first exciter shaft induces oscillating movement of the first cutter shaft and the first cutting disc. The second cutter head is movable through a second range of movement intersecting the first range of movement at an overlap region. The second cutter head includes a second cutter shaft, a second cutting disc, and a second excitation mechanism. The second cutting disc is supported for free rotation relative to the second cutter shaft about a second cutter axis. The second cutting disc includes a plurality of second cutting bits defining a second cutting edge. The second excitation mechanism includes a second exciter shaft and a second mass eccentrically coupled to the second cutter shaft. Rotation of the second exciter shaft induces oscillating movement of the second cutter shaft and the second cutting disc.

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 disclosure 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..

<FIG> illustrate a mining machine <NUM> (e.g., an entry development machine) including a chassis <NUM>, booms <NUM>, and cutter heads <NUM> for engaging a rock face <NUM> (<FIG>). In the illustrated embodiment, the machine <NUM> further includes a material handling system <NUM>. The chassis <NUM> is supported on a traction system (e.g., crawler mechanism <NUM>) for movement relative to a floor (not shown). The chassis <NUM> includes a first or forward end and a second or rear end, and a longitudinal chassis axis <NUM> extends between the forward end and the rear end. The booms <NUM> are supported on the chassis <NUM> by a yoke <NUM>.

As shown in <FIG>, in some embodiments, the yoke <NUM> is moveable relative to the chassis <NUM> in a direction parallel to the chassis axis <NUM> (e.g., toward or away from the rock face <NUM> - <FIG>) to permit sumping of the cutter heads <NUM>. In the illustrated embodiment, the material handling system <NUM> and the yoke <NUM> are movable together in a direction parallel to the chassis axis <NUM>, thereby permitting the cutter heads <NUM> to be advanced (e.g., in a forward direction <NUM>) without requiring re-positioning the chassis <NUM>. In some embodiments, the cutter heads <NUM>, the material handling system <NUM>, and the yoke <NUM> form a sumping frame. As shown in <FIG>, the sumping frame includes lateral pins <NUM> (<FIG>) projecting outwardly from each side of the sumping frame in a direction transverse to the chassis axis <NUM>. <FIG> shows a perspective view of a rear end of the chassis <NUM>, and the chassis <NUM> includes slots or guides <NUM> oriented parallel to the chassis axis <NUM> for receiving the pins <NUM>. An actuator (e.g., hydraulic cylinders - not shown) moves the sumping frame such that the pins <NUM> slide within the guides <NUM>.

As shown in <FIG>, each boom <NUM> includes a first portion or base portion <NUM> and a second portion or wrist portion <NUM> supporting a respective cutter head <NUM>. The base portion <NUM> includes a first end <NUM> secured to the yoke <NUM> and a second end <NUM> supporting the wrist portion <NUM>. In the illustrated embodiment, the first end <NUM> is secured to the yoke <NUM> by a first pin joint oriented in a first direction (e.g., vertical) and the wrist portion <NUM> is pivotably coupled to the base portion <NUM> by a second pin joint oriented in a second direction (e.g., transverse to the chassis axis <NUM>). First actuators <NUM> (e.g., fluid cylinders) may be coupled between the base portion <NUM> and the yoke <NUM> to move pivot the base portion <NUM> about the first pin joint, about a base axis <NUM>. In the illustrated embodiment, each boom <NUM> includes two first actuators <NUM>; in other embodiments, each boom <NUM> may have fewer or more actuators <NUM>.

Each wrist portion <NUM> is pivotable relative to the base portion <NUM> about the second pin joint due to operation of second fluid actuators (e.g., hydraulic cylinders) or luff actuators <NUM>. In the illustrated embodiment, extension and retraction of the luff actuators <NUM> causes the wrist portion <NUM> to pivot about a transverse axis <NUM> that is perpendicular to the base axis <NUM>. The wrist portion <NUM> may be pivoted between a first or lower position (<FIG>) and a second or upper position (<FIG>), or an intermediate position between the lower position and the upper position. Stated another way, the luff actuators <NUM> drive the wrist portion <NUM> to pivot within a plane that is parallel to the base axis <NUM> and the plane generally extends between an upper end of the machine <NUM> and a lower end of the machine <NUM>. In the illustrated embodiment, the machine <NUM> includes two luff cylinders <NUM>; in other embodiments, the machine <NUM> may include fewer or more actuators <NUM>. Also, in the illustrated embodiment, a lower edge of the cutter head <NUM> is positioned immediately forward of the material handling system when the cutter head <NUM> is in the lower position (<FIG>). In other embodiments, the configuration and orientation of the axes of movement can be modified to meet particular requirements. For example, in some embodiments, the axis about which the wrist portion <NUM> pivots may be defined by a pin extending in a substantially vertical orientation, and the axis about which the cutter head <NUM> may be defined by a pin extending in a substantially horizontal orientation. In some embodiments, these axes may intersect one another. In some embodiments, these axes may be coincident.

As shown in <FIG> and <FIG>, each cutter head <NUM> is coupled to a distal end of the respective boom <NUM>, at an end of the wrist portion <NUM> that is opposite the base portion <NUM>, and each cutter head <NUM> is supported by a pin connection. In the illustrated embodiment, the pin connection defines a slew axis or pivot axis <NUM> about which the cutter head <NUM> pivots. A third actuator or slew cylinder <NUM> (<FIG>) is coupled to between the cutter head <NUM> and the wrist portion <NUM> to pivot the cutter head <NUM> about the pivot axis <NUM>. The pivot axis <NUM> is generally oriented perpendicular to the luff axis or transverse axis <NUM>.

As discussed in further detail below, each cutter head <NUM> oscillates about transverse axis <NUM> and pivot axis <NUM>. In the illustrated embodiment, each luff cylinder <NUM> is operable to position the cutter head <NUM> about the transverse axis <NUM> and also acts as a spring or biasing member to permit rotary oscillations of the cutter head <NUM> at an excitation frequency caused by the operation of the excitation element <NUM> (described in more detail below). In a similar fashion, each slew cylinder <NUM> (<FIG>) is operable to position the respective cutter head <NUM> about the pivot axis <NUM> and may also act as a spring or biasing member to permit rotary oscillations of the cutter head <NUM> at the excitation frequency. In the illustrated embodiment, the cylinders <NUM>, <NUM> maintain alignment of the axes <NUM>, <NUM> of the cutter head <NUM> relative to the wrist portion <NUM>; in other embodiments, other orientations of the cutter head <NUM> may be controlled.

Referring now to <FIG>, the cutter head <NUM> includes a cutting member or bit or cutting disc <NUM> having a peripheral edge <NUM>, and a plurality of cutting bits <NUM> (<FIG>) are positioned along the peripheral edge <NUM>. The peripheral edge <NUM> may have a round (e.g., circular) profile, and the cutting bits <NUM> may be positioned in a common plane defining a cutting plane <NUM> (<FIG>). The cutting disc <NUM> may be rotatable about a cutter axis <NUM> that is generally perpendicular to the cutting plane <NUM>.

AS shown in <FIG>, the cutter head <NUM> includes a housing <NUM> generally extending along a housing axis <NUM>. An outer surface of the housing <NUM> includes lugs <NUM> that are coupled to the slew cylinders <NUM> (<FIG>). The housing <NUM> also includes projections <NUM> extending radially outward with respect to the housing axis <NUM>. The projections <NUM> are received within sockets (not shown) on the wrist portion <NUM> and generally define the pivot axis <NUM> about which the cutter head pivots relative to the wrist portion <NUM>.

As shown in <FIG>, the cutter head <NUM> further includes a shaft <NUM> removably coupled (e.g., by fasteners) to an end of the housing <NUM> that is opposite location of the projections <NUM> (<FIG>). The shaft <NUM> includes a first portion <NUM> positioned adjacent the housing <NUM> and a second portion <NUM> extending away from the housing <NUM>. The cutting disc <NUM> is rigidly coupled to a carrier <NUM> that is supported on the second portion <NUM> for rotation (e.g., by tapered roller bearings <NUM>) about the cutter axis <NUM>. In the illustrated embodiment, the second portion <NUM> is formed as a stub or cantilevered shaft generally extending in a direction parallel to the cutter axis <NUM>. Also, in the illustrated embodiment, the first portion <NUM> and the second portion <NUM> are separable components; in other embodiments, the first portion and the second portion may be integrally formed. In still other embodiments, the shaft may be formed as more than two separable components.

As shown in <FIG>, the cutter head <NUM> also includes an excitation element <NUM>. In the illustrated embodiment, the excitation element <NUM> is positioned in the first portion <NUM> of the shaft <NUM>. The excitation element <NUM> includes 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 spherical roller bearings <NUM>) relative to the first portion <NUM> of the shaft <NUM> about an exciter axis <NUM>. In the illustrated embodiment, the exciter axis <NUM> is aligned with the cutter axis <NUM>; in other embodiments, the cutter axis <NUM> may be offset or oriented at a non-zero angle relative to the exciter axis <NUM>. In the illustrated embodiment, the motor <NUM> is positioned adjacent a rear end of the cutter head <NUM>, opposite the projections <NUM>, and is coupled to the shaft <NUM> via an output shaft <NUM>. The motor <NUM> may include a torque arm to resist rotation of the motor <NUM>.

The rotation of the eccentric mass <NUM> induces an eccentric oscillation in the shaft <NUM>, thereby inducing oscillation of the cutting disc <NUM>. In the illustrated embodiment, the excitation element <NUM> is offset from the second portion <NUM> (i.e., the portion supporting the cutting disc <NUM>) in a direction parallel to the cutter axis <NUM>. In other embodiments, the excitation element <NUM> and cutter head <NUM> may be similar to the exciter member and cutting bit described in <CIT>.

In the illustrated embodiment, the cutting disc <NUM> is supported for free rotation relative to the shaft <NUM>; that is, the cutting disc <NUM> is neither prevented from rotating nor positively driven to rotate except by the induced oscillation caused by the excitation element <NUM> and/or by the reaction forces exerted on the cutting disc <NUM> by the rock face <NUM>.

Although only one of the booms <NUM> and one of the cutter heads <NUM> is described in detail above, it is understood that the other boom <NUM> and cutter head <NUM> includes substantially similar features. In the illustrated embodiment, the machine <NUM> includes a pair of booms <NUM> and cutter heads <NUM> laterally spaced apart from one another and positioned at substantially the same height. Each of the booms <NUM> and cutter heads <NUM> are movable independent of the other boom <NUM> and cutter head <NUM>. In other embodiments, the machine <NUM> may include fewer or more booms <NUM> and cutter heads <NUM>, and/or the booms <NUM> and cutter heads may be positioned in a different manner.

Referring now to <FIG>, each cutter head <NUM> engages the rock face <NUM> by undercutting the rock face <NUM>. The cutting disc <NUM> moves in a desired cutting direction across a length of the rock face <NUM>. A leading portion of the cutting disc <NUM> engages the rock face <NUM> at a contact point and is oriented at an acute angle relative to a tangent of the rock face <NUM> at the contact point, such that a trailing portion of the cutting disc <NUM> (i.e., a portion of the disc <NUM> that is positioned behind the leading portion with respect to the cutting direction) is spaced apart from the face <NUM>. The angle provides clearance between the rock face <NUM> and a trailing portion of the cutting disc <NUM>. In some embodiments, the angle is between approximately <NUM> degrees and approximately <NUM> degrees. In some embodiments, the angle is between approximately <NUM> degree and approximately <NUM> degrees. In some embodiments, the angle is between approximately <NUM> degrees and approximately <NUM> degrees. In some embodiments, the angle is approximately <NUM> degrees.

As shown in <FIG>, each cutter head <NUM> is independently movable through a range of movement that overlaps with the range of movement of the other cutter head <NUM>. However, the configuration of the booms <NUM> and cutter heads <NUM> permits overlapping, independent movement of each cutter head <NUM> without binding or interfering with the movement of the other cutter head <NUM>. The dual cutter head configuration and compact booms <NUM> permit the machine <NUM> to engage a wide section of the rock face <NUM> without requiring a large operating height. In some embodiments, the machine is capable of engaging the rock face <NUM> across a width of approximately <NUM> meters and along a height of approximately <NUM> meters. In addition, in some embodiments, the cutter heads <NUM> may engage the rock face <NUM> along a desired profile. Also, the use of inertially-excited cutter heads <NUM> may improve cutting rates, and increase overall mining efficiency compared to conventional entry development machines. The machine <NUM> may also reduce or eliminate the need for drill and blast operations, may reduce the incidence rate of injury, and may reduce overall operating cost compared to conventional entry development machines.

Referring again to <FIG>, the material handling system <NUM> includes a gathering head <NUM> and a conveyor <NUM>. The gathering head <NUM> includes an apron or deck <NUM> and rotating arms <NUM>. As the sumping frame advances, the cut material is urged onto the deck <NUM>, and the rotating arms <NUM> move the cut material onto the conveyor <NUM> for transporting the material to a rear end of the machine <NUM>. The conveyor <NUM> may be a chain conveyor and may be articulated relative to the chassis. In other embodiments, the arms may slide or wipe across a portion of the deck <NUM> (rather than rotating) to direct cut material onto the conveyor <NUM>. Furthermore, in other embodiments, the material handling system <NUM> may include another mechanism for removing material from an area in front of the machine <NUM> and directing the material onto the deck <NUM>.

The sumping frame and associated components (i.e., the booms <NUM>, cutter heads <NUM>, material handling system <NUM>, and yoke <NUM>) may be advanced or sumped toward the rock face <NUM>, permitting significant advancement of the cutting operation without requiring frequent relocation and readjustment of the machine <NUM>. This reduces the time that typically must be spent aligning the machine each time the machine is re-positioned in order to maintain a cut face that is parallel to the previous cut. In addition, the sumping function permits the cutter heads <NUM> and the material handling system <NUM> to maintain their relationship to one another as the face is advanced. In addition, as shown in <FIG>, the lower edges of the cutter heads <NUM> may be positioned close to the front of the deck <NUM> at floor level, which facilitates loading cut material onto the deck <NUM>.

Although the cutter head <NUM> has been described above with respect to a mining machine (e.g., an entry development machine), it is understood that one or more independent aspects of the boom <NUM>, the cutter head <NUM>, the material handling system <NUM>, and/or other components may be incorporated into another type of machine and/or may be supported on a boom of another type of machine. Examples of other types of machines may include (but are not limited to) drills, road headers, tunneling or boring machines, continuous mining machines, longwall mining machines, and excavators.

Also, as shown in <FIG>, in some embodiments, the machine <NUM> includes a stabilization system including a plurality of stabilizers or jacks. In the illustrated embodiment, four floor jacks <NUM> are coupled to the chassis <NUM>, with a pair of floor jacks <NUM> positioned proximate a rear end of the crawler mechanism <NUM> and a pair of floor jacks <NUM> positioned proximate a forward end of the crawler mechanism <NUM>. In addition, a pair of roof jacks <NUM> are positioned proximate a rear end of the chassis <NUM>. The floor jacks <NUM> are extendable to engage a floor surface and support the machine <NUM> off the ground during cutting, while the roof jacks <NUM> may be extended to engage a roof surface and therefore increase the load exerted on the floor jacks <NUM>. In some embodiments, the stabilization system is similar to the stabilization system described in <CIT>. The stabilization system may include fewer or more floor jacks and or roof jacks, and/or the jacks may be positioned in a different manner relative to the machine <NUM>.

<FIG> illustrate another embodiment of the mining machine <NUM>. The mining machine <NUM> is similar to the mining machine <NUM> described above, and only differences are described for the sake of brevity. Similar features are identified with similar reference numbers, plus <NUM>.

The mining machine <NUM> includes a yoke <NUM> including a first portion <NUM> and a second portion <NUM>. The first portion <NUM> extends between the booms <NUM>, and each boom <NUM> is pivotably coupled to the first portion <NUM>. The second portion <NUM> is an elongated member including one end secured to the first portion <NUM> and another end pivotably coupled to the sumping frame. The second portion <NUM> may be pivoted relative to the sumping frame by an actuator (e.g., a fluid cylinder - not shown). As a result, the yoke <NUM> may be pivoted vertically (e.g., about a transverse axis <NUM>) between a lower position (<FIG>) and a lower position (<FIG>). In some embodiments, the yoke <NUM> may be pivoted such that the cutter heads <NUM> can cut a height of approximately <NUM> meters. In one aspect, not covered by the appended claims, a mining machine comprises:.

Advantageously, the excitation mechanism further includes a motor for driving the exciter shaft relative to the cutter shaft.

Advantageously, the mining machine further comprises a yoke supported for movement relative to the frame, the boom pivotably coupled to the yoke, wherein movement of the yoke advances the cutter head toward a rock face.

Advantageously, the yoke is supported for translational movement relative to the frame in a direction parallel to a longitudinal axis of the frame, and the yoke is also supported by pivoting movement relative to the frame about an axis transverse to the longitudinal axis of the frame.

Advantageously, the exciter axis is aligned with the cutter axis.

Advantageously, the frame including a chassis and a sumping frame that is movable relative to the chassis, wherein the boom and the cutter head are supported on the sumping frame.

Advantageously, the mining machine further comprises a gathering head coupled to a base of the frame and including a deck having a forward edge, wherein when the cutter head is in a lowermost position, the cutting edge is positioned adjacent the forward edge of the deck.

Advantageously, the boom is a first boom and the cutter head is a first cutter head, the mining machine further comprising,.

Advantageously, the boom including a first portion and a second portion pivotably coupled to the first portion, the cutter head coupled to the second portion of the boom, wherein the first portion is pivotable about a first axis and the second portion is pivotable about a second axis that is substantially perpendicular to the first axis.

According to an aspect of the invention, a mining machine is provided comprising:.

Advantageously, the mining machine further comprises a yoke supported for movement relative to the frame, the first boom and the second boom each pivotably coupled to the yoke, wherein movement of the yoke advances the first cutter head and the second cutter head in a sump direction.

Advantageously, the mining machine further comprises a gathering head coupled to a base of the frame and including a deck having a forward edge, wherein when each cutter head is in a lowermost position, the respective cutting edge is positioned adjacent the forward edge of the deck.

Advantageously, each cutter shaft includes a first portion and a second portion, each cutting disc supported for rotation on the second portion of the respective cutter shaft, each excitation mechanism positioned adjacent the first portion of the respective cutter shaft.

Advantageously, each cutter head includes a motor for driving the respective exciter shaft about an exciter axis.

Advantageously, the frame includes a chassis and a sumping frame that is movable relative to the chassis, wherein the first boom and the second boom are coupled to a yoke supported on the sumping frame such that the first boom, the second boom, the first cutter head, and the second cutter head are movable relative to the chassis.

Claim 1:
A mining machine comprising:
a frame;
a first boom (<NUM>) supported for pivoting movement relative to the frame;
a second boom (<NUM>) supported for pivoting movement relative to the frame, the second boom being movable independent of the first boom;
a first cutter head (<NUM>) pivotably coupled to the first boom, the first cutter head movable through a first range of movement, the first cutter head including a first cutter shaft (<NUM>), a first cutting disc (<NUM>), and a first excitation mechanism, the first cutting disc supported for free rotation relative to the first cutter shaft about a first cutter axis (<NUM>), the first cutting disc including a plurality of first cutting bits (<NUM>) defining a first cutting edge (<NUM>), the first excitation mechanism including a first exciter shaft (<NUM>) and a first mass (<NUM>) eccentrically coupled to the first cutter shaft (<NUM>), rotation of the first exciter shaft inducing oscillating movement of the first cutter shaft and the first cutting disc; and
a second cutter head (<NUM>) pivotably coupled to the second boom (<NUM>), the second cutter head laterally offset from the first cutter head in a direction transverse to a longitudinal axis of the frame, the second cutter head movable through a second range of movement intersecting the first range of movement at an overlap region, the second cutter head being laterally movable into a position that overlaps a position of the first cutter head in a height direction of the frame, the second cutter head including a second cutter shaft (<NUM>), a second cutting disc (<NUM>), and a second excitation mechanism, the second cutting disc supported for free rotation relative to the second cutter shaft about a second cutter axis (<NUM>), the second cutting disc including a plurality of second cutting bits (<NUM>) defining a second cutting edge (<NUM>), the second excitation mechanism including a second exciter shaft (<NUM>) and a second mass (<NUM>) eccentrically coupled to the second cutter shaft (<NUM>), rotation of the second exciter shaft inducing oscillating movement of the second cutter shaft and the second cutting disc.