Cutting device with tapered cutting element

A cutting device for cutting rock includes a disc and a plurality of cutting elements secured to the disc. The disc is supported for rotation about an axis of rotation, and the disc includes a peripheral edge extending around the axis of rotation. The plurality of cutting elements are spaced apart along the peripheral edge of the disc and positioned in a cutting plane. Each of the cutting elements includes a base portion and a cutting portion including a cutting edge, and the cutting portion has a width that is larger than a width of the base portion.

BACKGROUND

The present invention relates to machines for mining or excavation, and more particularly to cutting devices for a machine for mining or excavation.

Mining machines may include rotating cutting discs to engage rock formations and walls cut or dislodge rock and/or mineral. The cutting disc may be rotated and driven to undercut the rock face at a narrow angle relative to the plane of the face, generating shear forces to cause the rock to fracture. Each cutting disc has a plurality of bits or buttons.

SUMMARY

In one aspect, a cutting device for cutting rock includes a disc and a plurality of cutting elements secured to the disc. The disc is supported for rotation about an axis of rotation, and the disc includes a peripheral edge extending around the axis of rotation. The plurality of cutting elements are spaced apart along the peripheral edge of the disc and positioned in a cutting plane. Each of the cutting elements includes a base portion and a cutting portion including a cutting edge, and the cutting portion has a width that is larger than a width of the base portion.

In another aspect, a cutting head for a mining machine includes a boom configured to be supported on a frame, a drive mechanism, and a cutting device supported on the boom and driven by the drive mechanism. The cutting device includes a disc and a plurality of cutting elements secured to the disc. The disc is supported for rotation about an axis of rotation, and the disc includes a peripheral edge extending around the axis of rotation. The plurality of cutting elements are spaced apart along the peripheral edge of the disc and positioned in a cutting plane. Each of the cutting elements includes a base portion and a cutting portion including a cutting edge. The cutting portion has a width that is larger than a width of the base portion.

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

DETAILED DESCRIPTION

FIG. 1illustrates an exemplary mining machine10including a frame14, a boom18, and a cutting head22supported on the boom18for engaging a mine wall. The frame14includes a drive system including traction devices, such as tracks30, for moving the frame14over a support surface or mine floor. In the illustrated embodiment, the frame14further includes a gathering head32positioned adjacent the mine floor proximate the cutting head22. The gathering head32includes a deck34and rotating members38that direct cut material from the deck34onto a conveyor42. In some embodiments, the frame14may also include arms for directing cut material onto the deck34. In the illustrated embodiment, the mining machine10includes a single cutting head; in other embodiments, the machine10may include multiple cutting heads.

As shown inFIG. 2, the cutting head22includes a cutting disc50having an outer edge or peripheral edge54, and the cutting disc50engages a mine wall (not shown) to remove rock from the wall. In the illustrated embodiment, the cutting head22further includes a carrier58and an arm62. The disc50is coupled to the carrier58, which is supported for rotation (e.g., by bearings64—FIG. 2A) relative to the arm62about an axis of rotation66. In the illustrated embodiment, the cutting disc50and/or carrier58are freely rotatable relative to the arm62. As shown inFIG. 2A, in the illustrated embodiment, the arm62includes a shaft70supporting the carrier58, and the cutting head22further includes an exciter assembly for inducing oscillation of the cutting head22. The exciter assembly includes an eccentric exciter mass80coupled to a shaft82and supported for rotation on the arm62, and a motor84for mechanically driving the exciter mass80to rotate. Rotation of the exciter mass80causes the cutting head22(including the cutting disc50) to oscillate.

In some embodiments, the cutting head and disc may operate in a manner similar to that of the mining machine disclosed in U.S. Patent Application Publication No. 2014/0077578, filed Sep. 16, 2013, the entire contents of which are incorporated by reference herein. In other embodiments, the cutting head and disc operates in a similar manner to the cutting mechanism disclosed in U.S. Pat. No. 7,934,776, published May 3, 2011, the entire contents of which are incorporated by reference herein. In other embodiments, the cutting disc may be is driven to rotate in another manner.

As shown inFIGS. 2 and 3, the cutting disc50includes a main support74secured to the carrier58, and a cutting ring78extending around the main support74. The cutting ring78forms the peripheral edge54positioned within a plane86(FIG. 2A). In the illustrated embodiment, the peripheral edge54is formed at a junction between an end surface90(FIG. 3) of the cutting ring78(e.g., a distal end of the disc50) and an outer lateral surface or peripheral surface94of the cutting ring78. In some embodiments, the plane86is coplanar with the end surface90of the cutting ring78and is perpendicular to the axis of rotation66(FIG. 2) of the cutting disc50. The peripheral surface94may have a substantially cylindrical or frustoconical shape, and may extend around the axis of rotation66.

As shown inFIGS. 3 and 4, a plurality of cutting elements or cutting buttons or cutting bits102are positioned along the peripheral edge54and spaced apart from one another (e.g., at regular intervals). In the illustrated embodiment, the peripheral edge54includes a plurality of bores106(FIG. 10), and each of the cutting bits102is positioned within an associated bore106. The main support74and/or the cutting ring78can be formed from rigid materials (e.g., steel and/or other metals), and the cutting bits102can be constructed from a material having high hardness (e.g., carbide).

Referring toFIG. 3, in the illustrated embodiment, the cutting ring78may be formed as a plurality of radial cutting sections110independently and removably coupled to the main support74(e.g., by fasteners, quick release connections, etc.). Each of the cutting sections110supports some of the cutting bits102. In the illustrated embodiment, the cutting sections110are coupled to the main support74and positioned around the axis of rotation66(FIG. 2), thereby defining a circular or round profile. In other embodiments, the cutting sections110may be positioned in a different manner. The detachable aspect of the cutting sections110provides a modular cutting disc50, allowing worn or degraded cutting sections110to be replaced individually without the need to replace the entire disc, reducing downtime due to maintenance. In other embodiments, however, the cutting ring78may be formed as a single unitary member supporting the cutting bits102.

As shown inFIGS. 5 and 6, each cutting bit102includes a first portion or base portion124, a second portion or transition portion128, and a third portion or cutting portion132. The base portion124includes a base end136defining a first end of the cutting bit102, and the cutting portion132includes a cutting tip or cutting edge138defining a second end of the cutting bit102. A longitudinal axis140extends between the base end136and the cutting edge138. In the illustrated embodiment, the base portion124has a cylindrical shape. The cumulative height of the base portion124, the transition portion128, and the cutting portion132defines a height H (FIG. 6). In some embodiments, the height H is between approximately 20 mm and approximately 40 mm. In some embodiments, the height H is between approximately 25 mm and approximately 35 mm. In some embodiments, the height H is approximately 31 mm.

The base portion124is positioned within an associated bore106(FIG. 10) of the cutting ring78. The base portion124includes an outer surface142having a width D2. The outer surface142is contiguous with a tapered base end136and the transition portion128. The transition portion128includes a tapered or inclined surface150extending outwardly from the outer surface142of the base portion124. The inclined surface150is contiguous with the base portion124and a shoulder154. The shoulder154has a width D1that is wider than the width D2of the outer surface142.

In the illustrated embodiment, the outer surface142and the shoulder154both have a circular profile, and the widths D1and D2represent diameters of the respective portions. In some embodiments, the shoulder154has a diameter D1between approximately 12 mm and approximately 20 mm. In some embodiments, the shoulder154has a diameter D1of approximately 16 mm. In some embodiments, the outer surface142has a diameter D2between approximately 7 mm and approximately 13 mm. In some embodiments, the outer surface142has a diameter D2of approximately 10 mm. In other constructions, one or more of these widths may have different dimensions.

Referring now toFIGS. 7-9, in the illustrated embodiment, the cutting portion132includes a chisel shape. That is, the cutting portion132includes a pair of major chisel surfaces166extending from the shoulder154to the cutting edge138. The major chisel surfaces166are angled relative to each other and each major surface166forms an angle A relative to the longitudinal axis140. In some embodiments, the angle A is between approximately 37 degrees and approximately 48 degrees. In some embodiments, the angle A is approximately 42 degrees. As shown inFIG. 8, the cutting portion132also includes a pair of minor surfaces170extending from the shoulder154to the cutting edge138on either side of the major chisel surfaces166. The minor surfaces170are angled relative to each other, and each minor surface170forms an angle B relative to the longitudinal axis140. In some embodiments, the angle B is between approximately 27 degrees and approximately 38 degrees. In some embodiments, the angle B is approximately 33 degrees. A transition between the major chisel surfaces154and the minor surfaces170may include a rounded or chamfered surface178(FIG. 9). In other embodiments, the cutting portion may have a different geometry (e.g., conical, parabolic, ballistic, etc.).

As shown inFIG. 10, each cutting bit102is received within an associated bore106of the peripheral edge54. In the illustrated embodiment, the base portion124and the transition portion128are received within the tapered bore106. The longitudinal axis140of the bit102may be oriented at an acute angle relative to the axis of rotation66(FIG. 2) and/or relative to the end surface90of the cutting ring78. The cutting edges138of the cutting bits102may be positioned within a cutting plane.

As shown inFIG. 11, in the illustrated embodiment, the inclined surface150of the transition portion128engages a corresponding tapered portion or countersink182in the tapered bore106, while the shoulder154and cutting portion132protrude from the bore106above the surface of the disc50. The cutting portions132of the bits102engage a rock face (not shown) during operation of the cutting head22. The engagement of the transition portion128and the countersink182provides a large surface area for distributing reaction loads exerted on the bits102and reducing bending stresses experienced by the bits162.

As shown inFIG. 11, the cutting bits102are received within the bores106of the cutting disc50. The tapered geometry of the cutting bits102and the bores106reduces the necessary space needed between the cutting portions132of adjacent bits102, permitting adjacent bits102to be positioned close to one another and providing a high density of cutting bits102per unit of surface area along the peripheral edge54of the cutting disc50. The geometry also decreases the bending stresses on the cutting bits102to increase durability. In addition, the geometry of the bits102increases the surface area of the cutting portions132that engages the rock face during operation.

Referring now toFIG. 12, in some embodiments the bores106extend through the cutting ring78, and a removal opening190is positioned adjacent a rear surface of the cutting ring78. The removal opening190is in communication with the bore106. A force F may be applied to the base end136of the bit102through the removal opening190to urge the cutting bit102out of the bore106. This force F may be a hydraulic force, a mechanical force, pneumatic force, or any other suitable force to remove the cutting bit102. For example, a tool198(FIG. 13) may include an end202that is inserted through the removal opening190to contact the base end136of the cutting bit102. The tool198may be actuated by a hydraulic press to remove the cutting bit102. The bits102may be removed from the cutting ring78, allowing a user to replace individual bits102that are damaged or worn.

Although certain aspects have been described in detail with reference to certain embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects as described. Various features and advantages are set forth in the following claims.