Patent Description:
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.

<CIT> describes a mobile mining machine which comprises a movable machine base frame, and a rotatable tool drum including excavating tools. The mobile mining machine further comprises a cantilever unit including a front support arm part and a base part, and a pivotal device to pivot the cantilever unit. The mobile mining machine further comprises a tilt device to tilt the cantilever unit and a rotary mechanism to rotate the support arm part and the tool drum.

<CIT> describes an extensible boom for mounting on a mobile rock breaking or mining machine, comprising an extensible member mouted for rotation about an axis extending in the direction of its length, a non-rotatable extensible member operative to impart extension to said rotatable member of the boom, means for extending the non-rotatatble extensible member of the boom and means on said rotatable member of the boom for mounting a rock breaking or other tool thereon.

<CIT> describes a machine which is for use in mining or tunnelling work and employs a beam or arm supporting cutting means and connected through a support structure to a turntable carried by a movable chassis.

<CIT> describes a rock boring device including a rotary disc cutter. The disc cutter is driven in an oscillating manner and also driven or free to nutate, and the device includes a mounting section for the rotary disc cutter and a driven section.

According to the present invention, there is provided a cutting assembly for a rock excavation machine as defined by independent claim <NUM>. Further advantageous features of the invention are defined by the dependent claims.

In one aspect, a cutting assembly for a rock excavation machine having a frame includes a boom supported on the frame and a cutting device. The boom includes a first portion and a second portion. The first portion includes a first structure and a second structure slidable relative to the first structure. The second portion includes a first member pivotably coupled to the second structure, and a second member pivotably coupled to the first member. The cutting device is supported on the second member.

In another aspect, a cutting assembly for a rock excavation machine having a frame includes a boom and a cutting device. The boom includes a first end supported on the frame and a second end. The boom further includes a first portion adjacent the first end and a second portion adjacent the second end. The second portion is supported for movement relative to the first end by a telescopic coupling and is pivotable relative to the first portion about an axis. The cutting device is supported on the second end of the boom.

In yet another aspect, a rock excavation machine includes a chassis, a boom supported on the chassis, a cutting device supported on the boom, and a material handling device supported on the chassis independently of the boom. At least a portion of the boom is movable relative to the chassis between a retracted position and an extended position. The material handling device is movable relative to the chassis between a retracted position and an extended position independent of the boom.

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 fluid 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>, a boom <NUM>, a cutter head <NUM> for engaging a rock face <NUM> (<FIG>), and a material handling system <NUM>. In the illustrated embodiment, the chassis <NUM> is supported on a 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 boom <NUM> is supported on the chassis <NUM> by a turntable or swivel joint <NUM>. The swivel joint <NUM> (<FIG>) is rotatable about a swivel axis <NUM> that is perpendicular to the chassis axis <NUM> (e.g., a vertical axis perpendicular to the support surface) to pivot the boom <NUM> in a plane that is generally parallel the chassis axis <NUM> (e.g., a horizontal plane parallel to the support surface). In the illustrated embodiment, the chassis <NUM> includes slew actuators or cylinders <NUM> for pivoting the swivel joint <NUM> and the boom <NUM> laterally about the swivel axis <NUM>.

As shown in <FIG>, the machine <NUM> also includes a service support member or bridge <NUM> extending between the chassis <NUM> and the boom <NUM>. In the illustrated embodiment, the bridge <NUM> includes a first portion 68a coupled to the chassis <NUM>, a second portion 68b coupled to the boom <NUM>, and an intermediate portion 68c coupled between the first portion 68a and the second portion 68c. The second portion 68b is substantially aligned with the swivel axis <NUM> but does not rotate with the boom <NUM>. In some embodiments, a bearing (not shown) permits sliding movement between the second portion 68b and the boom <NUM>. The intermediate portion 68c may be rigidly secured at each end to the first portion 68a and second portion 68b, respectively, or a coupling (e.g., a spherical joint) may permit some relative movement. The bridge <NUM> supports and/or guides various service lines (e.g., conduits, cables, wires, hoses, and pipes - not shown) between the chassis <NUM> and the boom <NUM>. The service lines may include electrical slip rings, rotary unions, or manifolds at connection points.

As shown in <FIG>, the boom <NUM> includes a first portion or base portion <NUM> and a second portion or wrist portion <NUM> supporting the cutter head <NUM>. Referring to <FIG> and <FIG>, in the illustrated embodiment, the wrist portion <NUM> is pivotably coupled to the base portion <NUM> by a pin joint <NUM>. The base portion <NUM> includes a first or stationary structure <NUM> secured to the swivel joint <NUM> and a second or movable structure <NUM>. The stationary structure <NUM> is pivotable with the swivel joint <NUM> and includes an opening <NUM> (<FIG>) receiving the movable structure <NUM>. The movable structure <NUM> is movable relative to the stationary structure <NUM> in a telescoping manner along a base axis <NUM>. Linear actuators or slide actuators <NUM> (e.g., fluid cylinders) may be coupled between the stationary structure <NUM> and the movable structure <NUM> to move the movable structure <NUM> between a retracted position (<FIG>) and an extended position (<FIG>). The slide actuators <NUM> may be coupled to the exterior surfaces of the stationary structure <NUM> and the movable structure <NUM>. In some embodiments, a sensor (e.g., a transducer - not shown) measures the stroke or position of the slide actuators <NUM>.

As shown in <FIG>, the movable structure <NUM> is supported relative to the stationary structure <NUM> by bearing assemblies <NUM>. In the illustrated embodiment, six bearing assemblies <NUM> are located in a common plane normal to the base axis <NUM>, with two bearing assemblies <NUM> abutting the upper and lower surfaces of the movable structure <NUM> and one bearing assembly <NUM> abutting each lateral surface of the movable structure <NUM>.

As shown in <FIG>, an additional set of bearing assemblies <NUM> may be positioned in a second plane normal to the base axis <NUM> and axially offset from the plane illustrated in <FIG>. In the illustrated embodiment, the second set includes four bearing assemblies <NUM>, with one bearing assembly <NUM> abutting each surface of the movable structure <NUM>. In other embodiments, the base portion <NUM> may include fewer or more bearing assemblies <NUM>, and the bearing assemblies <NUM> may be positioned in additional planes along the length of the base axis <NUM>. The bearing assemblies <NUM> may be positioned in a different manner. In the illustrated embodiment, the bearing assemblies <NUM> are accessible from an outer surface of the boom <NUM>; in other embodiments, the bearing assemblies <NUM> may be accessible only from an interior portion of the boom <NUM>.

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.

In addition, a shim pack <NUM> may be positioned between the main support <NUM> and the stationary structure <NUM> to adjust the position of the main support <NUM>. A spring pack (not shown) may be positioned between the main support <NUM> and the spherical bearing member <NUM> to provide an initial load or preload to ensure that the pad <NUM> maintains positive contact with the movable structure <NUM> during operation. In other embodiments, other types of bearing assemblies may be used.

As shown in <FIG>, the wrist portion <NUM> is pivotable relative to the base portion <NUM> due to operation of one or more fluid actuators (e.g., hydraulic cylinder) 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 <FIG>) and a second or upper position (<FIG> and <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 in 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, each luff actuator <NUM> includes a first end and a second end, with the first end coupled to the movable structure <NUM> of the base portion <NUM> and the second end coupled to the wrist portion <NUM>. Each actuator <NUM> extends through the base portion <NUM> of the boom <NUM>, such that the actuators <NUM> are positioned in the movable structure <NUM>. Also, the transverse axis <NUM> may be offset from the base axis <NUM> such that the transverse axis <NUM> and the base axis <NUM> do not intersect each other. 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>.

As shown in <FIG> and <FIG>, the wrist portion <NUM> includes a first member <NUM> proximate a first end <NUM> and a second member <NUM> proximate a second end <NUM>, and a wrist axis <NUM> extends between the first end <NUM> and the second end <NUM>. The first end <NUM> of the wrist portion <NUM> is coupled to the movable structure <NUM> of the base portion <NUM>, and therefore the wrist portion <NUM> translates or telescopes with the movable structure <NUM> in a direction parallel to the base axis <NUM>. The cutter head <NUM> (<FIG>) is positioned adjacent the second end <NUM> of the wrist portion <NUM>.

The cutter head <NUM> is positioned adjacent a distal end of the boom <NUM>. As shown in <FIG>, in the illustrated embodiment 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, 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>. In the illustrated embodiment, the cutter axis <NUM> is aligned with the wrist axis <NUM> (<FIG>).

As shown in <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> extends between the first lugs <NUM> and a second shaft <NUM> extends 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>. 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>. The second axis <NUM> may be substantially perpendicular to the cutter axis <NUM> (<FIG>). 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 the universal joint <NUM> permits the cutter head <NUM> to precess about the axes <NUM>, <NUM> of the universal joint <NUM>, and the joint <NUM> is capable of transferring shear and torque loads.

The cutter head <NUM> engages the rock face <NUM> by undercutting the rock face <NUM>. The cutting disc <NUM> traverses across a length of the rock face <NUM> in a cutting direction <NUM>. A leading portion of the cutting disc <NUM> engages the rock face <NUM> at a contact point and is oriented at an angle <NUM> relative to a tangent of the rock face <NUM> at the contact point. The cutting disc <NUM> is oriented at an acute angle <NUM> relative to a tangent of the rock face <NUM>, 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 <NUM>) is spaced apart from the face <NUM>. The angle <NUM> provides clearance between the rock face <NUM> and a trailing portion of 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.

Referring again to <FIG> and <FIG>, 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 suspension actuators <NUM> (e.g., hydraulic cylinders). The suspension actuators <NUM> may be independently operated to maintain a desired offset angle <NUM> (<FIG>) between the first member <NUM> and the second member <NUM>. In addition, the suspension actuators <NUM> may be filled with fluid and act similar to springs to counteract the reaction forces exerted on the cutter head <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 <NUM> 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> of the universal joint <NUM>. Each fluid cylinder <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 first member <NUM> and the second member <NUM>.

In other embodiments, the suspension system may include fewer or more suspension actuators <NUM>. The suspension actuators <NUM> may be positioned in a different configuration between the first member <NUM> and 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>. Also, in some embodiments, a fluid manifold <NUM> (e.g., a sandwich manifold - <FIG> and <FIG>) may be positioned between the first member <NUM> and the universal joint <NUM> to provide fluid communication to the suspension actuators <NUM>.

As shown in <FIG>, the cutter head <NUM> is positioned adjacent a second end <NUM> of the wrist portion <NUM> (<FIG>). The cutting disc <NUM> is rigidly coupled to a carrier <NUM> that is supported on a shaft <NUM> for rotation (e.g., by straight or tapered roller bearings <NUM>) about the cutter axis <NUM>. The cutter head <NUM> further includes a housing <NUM>. In the illustrated embodiment, the housing <NUM> is positioned between the second end <NUM> of the wrist portion <NUM> and the shaft <NUM>, and the housing <NUM> is formed as a separate structure that is removably coupled to the second end <NUM> of the wrist portion <NUM> (e.g., by fasteners) and is removably coupled to the shaft <NUM> (e.g., by fasteners). In some embodiments, the housing <NUM> is formed as multiple separate sections that are coupled together.

The housing <NUM> supports an excitation element <NUM>. The excitation element <NUM> includes an exciter shaft <NUM> and an eccentric mass <NUM> positioned on the exciter shaft <NUM>. The exciter shaft <NUM> is driven by a motor <NUM> and is supported for rotation (e.g., by straight or tapered roller bearings <NUM>) relative to the housing <NUM>. The rotation of the eccentric mass <NUM> induces an eccentric oscillation in the housing <NUM>, the shaft <NUM>, and the cutting disc <NUM>. 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>.

Referring now 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> (<FIG>). As the machine <NUM> 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 driven by one or more sprockets <NUM>. In the illustrated embodiment, the conveyor <NUM> is coupled to the gathering head <NUM> by a pin joint <NUM> and is supported for movement relative to the chassis <NUM> by a roller <NUM> (<FIG>). 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 also include a pair of articulated arms, each of which supports a bucket for removing material from an area in front of the machine <NUM> and directing the material onto the deck <NUM>.

As shown in <FIG>, the gathering head <NUM> and the conveyor <NUM> are coupled together and are supported for movement relative to the chassis <NUM>. Specifically, the gathering head <NUM> and conveyor <NUM> are coupled to the chassis <NUM> by a link <NUM> and a sumping actuator <NUM>. Although only one link <NUM> and sumping actuator <NUM> is shown in <FIG>, it is understood that the machine <NUM> may include a similar link <NUM> and sumping actuator <NUM> on each side of the machine <NUM>.

In the illustrated embodiment, a first end of the link <NUM> is pivotably coupled to the chassis <NUM> (e.g., proximate an upper end of the front of the chassis <NUM>) and a second end of the link <NUM> is pivotable coupled to the gathering head <NUM>. The sumping actuator <NUM> is coupled between the chassis <NUM> and the link <NUM> such that operation of the sumping actuator <NUM> moves the gathering head <NUM> and conveyor <NUM> relative to the chassis <NUM> (movement that is commonly referred to as "sumping"). The gathering head <NUM> and chassis <NUM> may be moved between a retracted position (<FIG> and <FIG>) and an extended position (<FIG> and <FIG>), and any intermediate position between the retracted position and the extended position. The stroke of the sumping actuators <NUM> may be measured with a sensor (e.g., an internal transducer - not shown). In some embodiments, the sumping actuators <NUM> include floating pistons to maintain the forward edge of the deck <NUM> against the ground.

In general, the coupling between the wrist portion <NUM> and the base portion <NUM> is positioned forward (i.e., distal) with respect to the telescoping coupling between the stationary structure <NUM> and the movable structure <NUM>. As a result, the articulating portion of the boom <NUM> is more compact, thereby reducing the area between the cutter head <NUM> and the forward edge of the gathering head <NUM>. Also, the material handling system <NUM> is coupled to the chassis <NUM> independent of the boom <NUM>. As a result, the material handling system <NUM> can be extended and retracted independent of the boom <NUM>. For example, the boom <NUM> may be extended relative to the chassis <NUM>, and the material handling system <NUM> may be extended by a distance that is greater than, less than, or equal to the extension of the boom <NUM>. This provides versatile control of the cutting and gathering operations. In some embodiments, the material handling system <NUM> can be extended and retracted through a linear distance of approximately <NUM>, and the boom <NUM> can be extended and retracted through a similar distance.

Claim 1:
A cutting assembly for a rock excavation machine (<NUM>), the rock excavation machine including a frame, the cutting assembly comprising:
a boom (<NUM>) supported on the frame, and a cutting device,
the boom including a first portion (<NUM>) and a second portion (<NUM>), the first portion including a first structure (<NUM>) and a second structure (<NUM>) slidable relative to the first structure (<NUM>), the second portion (<NUM>) including a first member (<NUM>) pivotably coupled to the second structure (<NUM>), and a second member (<NUM>) pivotably coupled to the first member (<NUM>), the boom further including a first fluid actuator (<NUM>) for pivoting the first member (<NUM>) relative to the first portion (<NUM>), a second fluid actuator (<NUM>) for driving sliding movement of the second structure (<NUM>) relative to the first structure (<NUM>), and at least one biasing member (<NUM>) coupled between the first member (<NUM>) and the second member (<NUM>); and
the cutting device supported on the second member,
characterised in that
the second member is pivotably coupled to the first member by a universal joint (<NUM>), the second portion further including a plurality of biasing members (<NUM>) coupled between the first member and the second member.