Patent Description:
The present disclosure relates to mining and excavation machines, and in particular to a support for a rock cutting device of a mining or excavation 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.

<CIT> describes cutting assemblies for rock excavation machines. <CIT> describes a cutting device for a cutting head. <CIT> describes a mining machine. <CIT> describes a rock excavating device. <CIT> describes a cutting assembly for a rock excavation machine having a frame includes a boom and a cutting device supported on the boom. The boom includes a first portion and a second portion, the first portion supported for pivotable movement relative to the frame. In some embodiments, the first portion includes a first structure extending along a longitudinal base axis and a second structure moveable relative to the first portion in a direction parallel to the longitudinal base axis, and at least one bearing supports the second portion for movement relative to the first portion. In some embodiments, the second portion is pivotably coupled to the first portion by a universal joint, and a suspension system including a plurality of biasing members may be coupled between the first portion and the second portion.

The scope of the invention is set out in independent claim <NUM> with further alternatives as set out in the dependent claims. A cutting assembly is provided for a rock excavation machine including a frame. The cutting assembly includes a boom, a cutting device, and a plurality of fluid actuators. The boom includes a base portion and a movable portion. The base portion is configured to be supported by the frame, and the movable portion is supported for sliding movement relative to the base portion in a direction parallel to a longitudinal axis of the base portion. The boom further includes a wrist portion pivotably coupled to the movable portion at a pivot joint. The cutting device is supported on a distal end of the wrist portion. The plurality of fluid actuators are coupled between the base portion and the wrist portion. The fluid actuators are operable to move the movable portion and the wrist portion parallel to the longitudinal axis, and the fluid actuators are also operable to bias the wrist portion against cutting loads exerted on the cutting device.

The pivot joint is a universal joint, and the fluid actuators are spaced apart at equal angular intervals about the longitudinal axis, each of the fluid actuators positioned radially outward from an outer surface of the boom.

The base portion is configured to be supported on a swivel to pivot laterally relative to the frame about a swivel axis, and the base portion is pivotably coupled to the swivel and supported for pivoting movement about a luff axis transverse to the swivel axis.

The movable portion is supported relative to the base portion by a plurality of bearings, each bearing including an outer race engaging the base portion, an inner race engaging the movable portion, and an intermediate member positioned between the outer race and the inner race.

Extension and retraction of the fluid actuators causes the movable portion to slide relative to the base portion.

The movable portion includes a cross-section having a round profile, the movable portion supported for sliding movement relative to the base portion by a plurality of bearings, each bearing including an inner race and an outer race extending substantially around the profile of the movable portion.

The cutting assembly further comprising a collar coupled to the movable portion, and at least one torque arm coupled between the collar and the base portion.

The wrist portion includes a plurality of support lugs extending radially outward from an outer surface of the wrist portion, each of the fluid actuators coupled to an associated one of the support lugs.

The cutting device includes a cutting disc having a peripheral edge defining a cutting plane, the cutting plane oriented in a direction substantially perpendicular to a longitudinal axis of the second portion of the boom.

The cutting device includes a cutting disc and an excitation device, the excitation device including an eccentric mass supported for rotation in an eccentric manner and positioned proximate the cutting disc, wherein rotation of the eccentric mass induces oscillation of the cutting device.

A cutting assembly is provided for a rock excavation machine including a frame. The cutting assembly includes a boom, a cutting device, and at least one fluid actuator. The boom is supported on the frame, and the boom including a first portion and a second portion. The second portion includes a first member supported for sliding movement relative to the first portion, and the second member is pivotably coupled to the first member at a pivot joint. The cutting device is supported on the second member. The at least one fluid actuator is coupled between the first portion and the second member, and supports the second member against cutting loads exerted on the cutting device.

The pivot joint is a universal joint, and wherein the at least one fluid actuator includes a plurality of fluid actuators spaced apart at equal angular intervals about a longitudinal axis of the boom, each of the fluid actuators positioned radially outward from an outer surface of the boom.

The first portion is supported on a swivel to pivot laterally relative to the chassis about a swivel axis, and the first portion is pivotably coupled to the swivel and supported for pivoting movement about a luff axis transverse to the swivel axis.

The first member is supported relative to the first portion by a plurality of bearings, each bearing including an outer race engaging the first portion, an inner race engaging the first member, and an intermediate member positioned between the outer race and the inner race.

Extension and retraction of the at least one fluid actuator causes the first member to slide relative to the first portion.

The cutting assembly further includes a collar coupled to the first member, and at least one torque arm coupled between the collar and the first portion.

A cutting assembly is provided for a rock excavation machine including a frame. The cutting assembly includes a boom, a plurality of bearings, a cutting device, and a plurality of fluid actuators. The boom is configured to be supported by the frame, and the boom includes a base portion and a movable portion received within the base portion. The movable portion is supported for sliding movement relative to the base portion in a direction parallel to a longitudinal axis of the base portion. The boom further includes a wrist portion pivotably coupled to the movable portion at a pivot joint. The bearings support the movable portion for sliding movement relative to the base portion, and each bearing includes an outer race engaging the base portion and an inner race engaging the movable portion. The cutting device is supported on a distal end of the wrist portion. The fluid actuators are coupled between the base portion and the wrist portion. The fluid actuators are operable to move the movable portion and the wrist portion parallel to the longitudinal axis, and the fluid actuators also operable to bias the wrist portion against cutting loads exerted on the cutting device.

The pivot joint is a universal joint, and the fluid actuators are spaced apart at equal angular intervals about a longitudinal axis of the boom, each of the fluid actuators positioned radially outward from an outer surface of the boom.

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> and <FIG> illustrate an excavation 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 <NUM>. The swivel <NUM> is rotatable (e.g., by operation of hydraulic cylinders or slew actuators <NUM>) about a swivel axis <NUM> that is perpendicular to the chassis axis <NUM> (e.g., a vertical axis perpendicular to the support surface), and rotation of the swivel <NUM> pivots the boom <NUM> laterally about the swivel axis <NUM>.

In the illustrated embodiment, the boom <NUM> is pivotably coupled to the swivel <NUM> at a luff pivot coupling <NUM>, and luff actuators <NUM> (e.g., hydraulic cylinders) are operable to pivot the boom <NUM> and change an elevation of the cutter head <NUM>. Stated another way, the luff actuators <NUM> pivot the boom about a luff pivot axis <NUM> that is substantially transverse to the chassis axis <NUM>.

As shown in <FIG>, the boom <NUM> includes a first portion or base portion <NUM> and a second portion <NUM> supporting the cutter head <NUM>. In the illustrated embodiment, the base portion <NUM> includes the luff pivot couplings <NUM> and first support lugs <NUM>. In addition, the base portion <NUM> includes an opening or bore <NUM> (<FIG>) extending along a boom axis <NUM>. The second portion <NUM> is supported for movement relative to the base portion <NUM>. The first support lugs <NUM> protrude radially outward from the boom axis <NUM>.

As shown in <FIG>, in the illustrated embodiment, the second portion <NUM> includes a cylindrical portion <NUM>, and the cylindrical portion <NUM> is at least partially positioned in the bore <NUM> of the base portion <NUM> and is movable relative to the base portion <NUM> in a telescoping manner along the boom axis <NUM>. The cylindrical portion <NUM> is supported relative to the base portion <NUM> by bearings <NUM> positioned adjacent each end of the bore <NUM>. As shown in <FIG>, in the illustrated embodiment, each bearing <NUM> includes an outer race <NUM>, an inner race or bushing <NUM>, and a wedge <NUM> positioned between the outer race <NUM> and the bushing <NUM>. The outer race <NUM> is secured to an inner surface of the bore <NUM>. The bushing <NUM> is retained against movement relative to the base portion <NUM> (e.g., by an end cap <NUM>), and has a sliding interface with the cylindrical portion <NUM>. The wedge <NUM> is positioned between the outer race <NUM> and the bushing <NUM>. The wedge <NUM> can provides radial adjustment to account for wear of the bushing <NUM>, and can assist in avoiding backlash or clearance between the bushing and cylindrical portion <NUM>. In some embodiments, the bushing <NUM> may be split into multiple segments spaced around the boom axis <NUM>.

Referring again to <FIG>, the second portion <NUM> further includes a collar <NUM> positioned adjacent a distal end of the cylindrical portion <NUM>, and a wrist portion <NUM> pivotably coupled to the collar <NUM>. The cutter head <NUM> is positioned adjacent a distal end of the wrist portion <NUM>. In the illustrated embodiment, the wrist portion <NUM> is coupled to the collar <NUM> by a universal joint <NUM> permitting the wrist portion <NUM> to pivot relative to the collar <NUM> about two pivot axes (not shown). In the illustrated embodiment, the universal joint <NUM> includes a hub <NUM> positioned radially within the collar <NUM>. The hub <NUM> may include first shaft portions rotatable relative to the collar <NUM> and second shaft portions rotatable relative to the wrist portion <NUM>. The first shaft portions define a first pivot axis, and the second shaft portions define a second pivot axis. In some constructions the pivot axes are oriented substantially perpendicular to the boom axis <NUM> and substantially perpendicular to each other. In some embodiments, the universal joint <NUM> may be similar to a universal joint described in <CIT>, the entire contents of which are incorporated by reference herein. 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 pivot axes.

Referring again to <FIG>, an outer surface of the wrist portion <NUM> includes second support lugs <NUM>, each of which is aligned along the boom axis <NUM> with one of the first support lugs <NUM> of the base portion <NUM>. The second support lugs <NUM> protrude radially outward from the outer surface of the wrist portion <NUM>. A suspension system includes linear actuators <NUM> (e.g., fluid cylinders) coupled between the first support lugs <NUM> and the second support lugs <NUM>.

The linear actuators <NUM> are operable to extend and retract the second portion <NUM> relative to the base portion <NUM>. For example, extending/retracting all of the linear actuators <NUM> simultaneously will extend/retract the second portion <NUM> in a direction parallel to the boom axis <NUM>. Also, operating the linear actuators <NUM> independently of one another (that is, extending/retracting fewer than all of the linear actuators <NUM> at the same time) will cause the wrist portion <NUM> to pivot about the universal joint <NUM> and position the cutter head <NUM> at an angular offset relative to the boom axis <NUM> (see <FIG>). In addition, the linear actuators <NUM> can bias the wrist portion <NUM> in a desired orientation relative to the universal joint <NUM>, thereby acting as biasing elements (similar to springs) to react to static and impact loads exerted on the cutter head <NUM> by the rock surface <NUM> (<FIG>).

In the illustrated embodiment, the suspension system includes four fluid cylinders <NUM> spaced apart from one another about the boom axis <NUM> by an angular interval of approximately <NUM> degrees. The cylinders <NUM> extend in a direction that is generally parallel to the boom axis <NUM>. In the illustrated embodiment, the suspension system includes four linear actuators, although other embodiments may include fewer or more linear actuators, and/or the linear actuators may be positioned in a different manner. In some embodiments, the cutter head <NUM> can be extended and retracted in a direction parallel to the boom axis <NUM> by a distance of <NUM>, enabling the cutter head <NUM> to perform multiple cutting passes without the need to re-position the machine <NUM> after each pass. In addition to permitting the cutter head <NUM> to be extended/retracted to a desired depth along the boom axis <NUM> and to be positioned at a desired angular orientation relative to the boom axis <NUM>, the linear actuators <NUM> transfer loads caused by the cutting forces around the universal joint <NUM>, thereby reducing the loads that are exerted on the components of the universal joint <NUM> and assisting to isolate the components and structures to the rear of the universal joint <NUM> against the vibrational forces exerted on the cutter head <NUM>.

Referring to <FIG> and <FIG>, torque arms <NUM> extend between the collar <NUM> and the base portion <NUM> and resist torques and torsional loads exerted on the second portion <NUM> about the boom axis <NUM>. In the illustrated embodiment, the boom <NUM> includes a pair of torque arms <NUM>, with one torque arm <NUM> positioned on each lateral side of the second portion <NUM>. Also, an end of each torque arm <NUM> is secured to the collar <NUM> and is slidable relative to the base portion <NUM>. In other embodiments, the boom <NUM> may include fewer or more torque arms, and/or the torque arms may be configured in a different manner.

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, and a plurality of cutting bits <NUM> are positioned along the peripheral edge. The peripheral edge may have a round (e.g., circular) profile. The cutting bits <NUM> may be positioned in a common plane defining a cutting plane <NUM>. The cutting disc <NUM> may be rotatable about a cutter axis <NUM> that is generally normal to the cutting plane <NUM>. In the illustrated embodiment, the cutter axis <NUM> is aligned with a longitudinal axis of the wrist portion <NUM> (<FIG>).

The cutter head <NUM> engages the rock surface <NUM> (<FIG>) by undercutting the rock surface. The cutting disc <NUM> traverses across a length of the rock surface in a cutting direction. For example, with respect to the view shown in <FIG>, the cutting direction may be into or out of the plane of the page. A leading portion of the cutting disc <NUM> engages the rock surface <NUM> at a contact point and is oriented at an angle relative to a tangent of the rock surface <NUM> at the contact point. In some embodiments, the cutting disc <NUM> is oriented at an acute angle relative to a tangent of the rock surface <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) is spaced apart from the surface <NUM>, thereby providing clearance between the rock surface <NUM> and the trailing portion of the cutting disc <NUM>.

As shown in <FIG>, the cutter head <NUM> is positioned adjacent a distal end of the wrist portion <NUM>. 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 distal end of the wrist portion <NUM> and the shaft <NUM>, and the housing <NUM> is formed as a separate structure that is removably coupled (e.g., by fasteners) to the wrist portion <NUM> and removably coupled (e.g., by fasteners) to the shaft <NUM>. 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 spherical 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 rotation is generally centered about the universal joint <NUM>. In some embodiments, the excitation element and cutter head 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>. Stated another way, the cutting disc <NUM> is neither prevented from rotating (other than by inertial or frictional forces that may inhibit rotation), nor positively driven to rotate, except to the extent that the induced oscillation caused by the excitation element <NUM> and/or by the reaction forces exerted on the cutting disc <NUM> by the rock surface <NUM> (<FIG>) cause the disc <NUM> to rotate.

Referring now to <FIG>, the material handling system <NUM> includes a gathering head <NUM> and a conveyor <NUM> coupled to the gathering head <NUM>. The gathering head <NUM> includes an apron or deck <NUM> and rotating arms <NUM>, and the gathering head <NUM> can be pivoted relative to the conveyor <NUM> by cylinders <NUM>. As the machine <NUM> advances, the cut material is urged onto the deck <NUM>, and the rotating arms <NUM> move the cut material toward 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, with flights or bars for moving cut material along a pan. In other embodiments, the material handling system <NUM> may include other devices for moving cut material from an area in front of the machine <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 a carrier frame <NUM> that is supported on the chassis <NUM>. Sumping actuators <NUM> are coupled between the chassis <NUM> and the carrier frame <NUM> such that operation of the sumping actuators <NUM> moves the gathering head <NUM> and conveyor <NUM> relative to the chassis <NUM> in a direction parallel to the chassis axis <NUM> (movement that is commonly referred to as "sumping"). In the illustrated embodiment, the material handling system <NUM> can be extended and retracted independent of the extension/retraction of the boom <NUM>, providing versatile control of the cutting and gathering operations.

Although the cutting device support 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 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.

Claim 1:
A cutting assembly for a rock excavation machine, the rock excavation machine including a frame, the cutting assembly comprising:
a boom (<NUM>) supported on the frame (<NUM>), the boom (<NUM>) including a first portion (<NUM>) and a second portion (<NUM>), wherein the second portion (<NUM>) includes a first member (<NUM>) supported for sliding movement relative to the first portion (<NUM>) and a second member (<NUM>) pivotably coupled to the first member (<NUM>) at a pivot joint (<NUM>);
a cutting device supported on the second member (<NUM>); and
at least one fluid actuator (<NUM>) including a first end directly coupled to the first portion (<NUM>) and a second end directly coupled to the second member (<NUM>), the at least one fluid actuator (<NUM>) being operable to both translate and pivot the second member (<NUM>) relative to the first portion (<NUM>), the at least one fluid actuator (<NUM>) supporting the second member (<NUM>) against cutting loads exerted on the cutting device.