Roadheader and Cutter Head Therefor

This application claims priority under 35 U.S.C. § 119 to EP patent application Ser. No. 23/219,951.3, filed on Dec. 22, 2023, which the entirety thereof is incorporated herein by reference.

The invention refers to a roadheader and a transverse cutter head therefor, wherein the cutter head has an outer surface including a plurality of cutting tools, and wherein the tips of the cutting tools define a contour.

For the excavation of tunnels, galleries and the like, including rock and seam sections in underground mining operations, and mineral production, e.g. of coal, rock, gypsum, potash, salt and metal, roadheaders are used, which are equipped with a cross-cutting head mounted on a boom. One type of roadheader typically has two transverse cutter heads mounted on a cutter boom, which are driven to rotate about an axis transverse to a longitudinal direction represented by the cutter boom axis. The boom extends from a main body of the roadheader and can be swivelled in different directions. Such a roadheader is able to cut rock with a high compressive strength. For that, the cutter head has a plurality of cutting tools arranged at the outer surface of each cutter head.

EP 2 208 856 discloses another type of roadheader including a longitudinal cutter head having a rotation axis that is generally parallel to or aligned with the axis of a cutter boom. At the outer surface of the cutter head, cutting tools are arranged forming a contour. The known cutter head has a particularly adapted contour design for this type of cutter head. For a better break-in behaviour, the cutter head includes hard rock breakers arranged on the front side of the cutting head close to the axis of rotation, which are offset inwards in the axial direction of the cutter head.

A transverse cutter head for a roadheader is disclosed in document DE 38 06 335 A1. One cutter head includes several annular discs, which are welded together in surface contact with each other both on the outer circumference and on the inner circumference. The cutter head further includes chisel holders for replaceable chisels which generally consist of round shank chisels, wherein the chisel holders are welded to the outer casing of the base body of the cutter head formed by the annular discs.

Document CN 113565502 A shows another transverse cutter head having a plurality of cutting tools at its outer surface. As one can derive, the cutting tools are arranged at and fixed along spiral grooves provided at the outer surface of the cutter head.

The above known transverse cutter heads have a rounded cutting contour formed by cutting tool tips rotating about the rotation axis of the respective cutter head, for example, at a section close to the rotation axis of the cutter head (side wall cutting area). Such rounded contour leads to irregular wear of the cutting tools located within this section.

Accordingly, it is an object of the invention to provide a cutter head for transverse cutting that has regular wear. Furthermore, it is an object to provide a respective roadheader having such cutter head.

The above object is solved by a transverse cutter head having the features of claimand a road header having the features of claim. The cutter head is configured to be mounted onto a cutter boom e.g. via a shaft (which may include drive/gear mechanism).

In particular, the above object is solved by a transverse cutter head for a mining machine (e.g., a roadheader) with an outer surface including a plurality of cutting tools, wherein the tips of the plurality of cutting tools define a virtual contour line, e.g., when viewed in a cutter boom longitudinal direction and a full rotation of the cutter head is considered. The contour line is formed by at least four sections, namely a first section, a second section, a third section and a fourth section. The four sections are located adjacently in this order, wherein the first section is located closest to the cutter boom (i.e. toward the gear of the cutter head, or, on the inner side) and the fourth section forms the side wall cutting area (i.e., departing away from the gear of the cutter head, or, on the outer side), wherein the first section and/or the fourth section run substantially straight.

Each one of the first section, the second section and the third section has a pitch angle different from the pitch angle of the other two sections. The pitch angle is understood as an angle between a section of the contour line and a rotation axis of the cutter head. To provide additional clarification on the matter mentioned above, the rotation of the cutting tool tips leaves a series of traces that delineates a hypothetical surface or contour or periphery (i.e., delineates a continuous surface which is achieved through interpolation); a contour line e.g. in a form of curve or polyline is understood as a 2-dimensional entity (e.g., curve or polyline) defined by the intersection of the hypothetical surface with a plane running through the rotation axis of the cutter head. To put it differently, intersecting of adjacent traces with a plane running through the rotation axis of the cutter head leaves 2 points, these 2 points are connected by a line which forms a part of the contour line.

The cutter head is composed of a cylindrical and/or conical cutter head housing rotatably mounted on the cutter boom and the plurality of cutting tools attached to the outer surface of the cutter head housing.

In an embodiment, each one of the plurality of the cutting tools is fixed at the outer surface of the cutter head such that a longitudinal axis of the respective cutting tool runs inclined to the outer surface (e.g. a tangent at the outer surface within the fixing area) and that the cutting tool tip points towards the rotation direction of the cutter head. These may be realized using one cutting tool holder for each cutting tool in the way that each cutting tool of the plurality of cutting tools is accommodated within and fixed to a cutting tool holder, wherein the plurality of cutting tool holders is, for example, welded to the outer surface of the cutter head housing. For accommodation of the cutting tool, each cutting tool holder includes an opening or recess for insertion and fixing of the cutting tool shaft. The cutting tool may be detachably accommodated within the opening of the respective cutting tool holder. The fixing may be provided by an internal or external retaining ring or an internal friction retainer. Each cutting tool may be accommodated within the cutting tool holder or the opening may be provided with an oblique course such that the cutting tool protrudes from the outer surface of the cutter head housing and runs inclined to the outer surface of the cutter head and the respective circumferential direction. The pointing direction of the cutting tools is generally the rotation direction, wherein in one embodiment a longitudinal axis of each cutting tool is inclined by an angle equal to or less than 70° against a tangent on the outer surface of the cutter head housing at the position of the cutting tool holder.

The cutting tool may be, for example, a point attack pick, a radial pick or a chisel type pick.

The tip of the respective cutting tool is the end tip of the cutting tool that is farthermost from the outer surface of the cutter head housing. The plurality of tips of all the cutting tools of one cutter head span a virtual outer contour which is a line in particular a polyline that can be drawn above and below the rotation axis of the respective cutter head with respect to any longitudinal section of the cutter head. This line contains all the positions of all the cutting tool tips of the cutter head when the respective cutting tool tip crosses the plane of the respective longitudinal section correspondingly above or below the rotation axis during one full rotation of the cutter head. All the determined positions of the cutting tool tips are connected by a line—the contour line. By means of the contour line and its structure the features of the cutter head will be explained in the following in more detail.

The virtual contour line is formed by the plurality of tips of all cutting tools of one cutter head thereby representing the mining position of all the cutting tools relative to the rotation axis of the cutter head. The contour line has at least four sections, wherein the first section of the contour is located closest to the gearbox of the cutter head, e.g. closest to the cutter boom of the roadheader. The second section of the contour is the one realizing the maximum cutting diameter of the cutter head. When performing a sumping operation, this section contacts and cuts the mining seam first. The third section is located between the second section and the fourth section and is usually the main cutting section, wherein the fourth section forms the side wall cutting area that is located radially farthermost from the cutter boom.

With regard to the present disclosure “adjacently in this order” means that they are provided in this sequence. It does not necessarily mean that these sections are located directly adjacently. For example, in one embodiment, the cutter head has the four sections only that are located directly adjacently, whereas in another embodiment, the cutter head has more than four sections, e.g., it may have an additional section between the third section and the fourth section and/or between the second section and the third section.

The substantially straight contour form of a section (e.g. the first section and/or the fourth section) leads to particular less irregular wear of the cutting tools of this section. This is because in the straight section, the pitch is the same over the whole section (pitch is used interchangeably with pitch angle). Accordingly, the cutting tools of the fourth section, and in the same manner the cutting tools of the first section, equally interact with the rock and seam section so that the wear of the cutting tools is equal, as well. In connection with this feature the definition “substantially straight contour” means that over 80% of the respective section of the contour line, for example over 90% of the respective section, is straight.

Additionally, the pitch angle of the at least three sections (second, third and fourth sections) of the cutter head may be better adapted/adjusted to the cutting task of the cutter head. With this cutter head design the same cutting parameters are realized at every cutting tool position inside the whole cutting area. This is not possible with a bended or curved contour. The advantage of equal cutting conditions for all cutting tools is that the maintenance efforts can be reduced. This is because all the cutting tools will wear down more or less simultaneously. Additionally, this results in a smoother torque consumption curve, which has a positive influence on the service lifetime of all parts of the roadheader, not just the cutter drive and gear box. Another advantage is that it is possible to design a cutter head for each geology according to optimum results, found during rig tests. This leads to optimum production rates due to reduced maintenance and optimum cutting behaviour.

In an embodiment, the first section of the contour line has a length L1 and the third section has a length L3, wherein L3≥2.2×L1, for example L3=2.2×L1 . . . 2.8×L1 (i.e., 2.2×L1≤L3≤2.8×L1, L3 is a multiple of L1, where the multiplier is within the range of 2.2 to 2.8). In this embodiment the third section is the main cutting section. Accordingly, it has a substantially greater length L3 than the length L1 of the first section, or L3 must be at least as long as L1. Alternatively, the length L1 of the first section approximately corresponds to the length L3 of the third section. This embodiment is used for sump in operation.

It is noted that the terms “length of a contour line” (L1, L2, L3, L4) and “contour length” are synonymous and can be used interchangeably. Each represents the extension of the cutting tool contour line determined in a direction parallel to the rotation axis of the cutter head from the cutting tool group located closest to the cutter boom to the cutting tool group arranged farthest away from the cutter boom. In other words, it represents the extent of the contour line (e.g., including one or more sections) projected onto the rotation axis of the cutter head.

It is understood that, the longer L1, the deeper the cutter head may sump into the rock before a swivelling operation of the cutter head is needed. The reason behind this is, considering the horizontal distance between an outermost pick whose tip has the maximal radius (departing from the rotation axis of the cutter head) and the gear box housing (or the boom side face), the bigger this distance, the deeper the cutter head may sump into the rock. This fact (deeper sump distance) may increase the production rate of the whole machine system.

For the same reason, L3 shall be maintained larger, as L3 is the main production area, L3 plays significant role in the production rate of the cutter head, in order to maximize production rate, L3 is at least be as long as L1, and preferably longer as L1 and also not shorter than all other lengths of the contour line (L1, L2, L4), as other sections (L1, L2, L4) are for secondary activities only.

In an embodiment, the second section of the contour line has a length L2, wherein L3≥2.2×L2, for example L3=2.2×L2 . . . 2.8×L2 (i.e. 2.2×L2≤L3≤2.8×L2). The main cutting section (third section) is greater than the second section for the same reason that it is greater than the first section.

In an embodiment, the fourth section of the contour line has a length L4, wherein L3≥2.2×L4, for example L3=2.2×L4 . . . 2.8×L4 (i.e. 2.2×L4≤L3≤2.8×L4). The main cutting section (third section) is greater than the fourth section (side wall cutting area) for the same reason that it is greater than the first section.

With regard to above embodiments, the lengths L1, L2, L3 and L4 are determined along the respective line section.

In an embodiment, the second section of the contour line is a substantially straight section. In an embodiment, the second section may be substantially parallel to the rotation axis of the cutter head and may, accordingly, have a pitch angle A2, wherein 0.5°≥A2≥−0.5°. Each pitch angle A1, A2, A3, A4 mentioned in this document is measured in a plane of a longitudinal section containing the contour and the rotation axis of the cutter head and with respect to the rotation axis of the cutter head.

According to the geology of the material to be cut using the cutter head, the first and/or third sections of the contour line may be adapted. Accordingly, in one embodiment, the third section has a pitch angle A3, wherein 28°=<A3<=42° e.g. chosen according to geology of the material to be cut using the cutter head, and/or in an embodiment, the first section has a pitch angle A1, wherein −42°=<A1<=−28° e.g. chosen according to geology of the material to be cut using the cutter head.

In the same manner, the pitch angle of the fourth section of the contour line (i.e. the side wall cutting area) may be adapted to the width of a roadway to be cut using the cutter head. In an embodiment, the fourth section has a pitch angle A4, wherein 33°=<A4<=55°, e.g., chosen according to a width of a roadway to be cut using the cutter head (). In an embodiment the pitch angle A4 of the fourth section of the contour line is greater than the pitch angle A3 of the third section of the contour line.

In an embodiment, within at least one of the first section, the second section, the third section and the fourth section of the contour line at least two groups of cutting tools, each cutting tool group including at least two cutting tools, are arranged such that the tips of the cutting tools of the same group form a virtual circle around the outer surface of the cutter head, wherein two adjacent groups of cutting tools of the at least one section have a pre-defined distance, wherein the distance is measured in a direction parallel to the rotation axis of the cutter head. Within the same section, the distance between two adjacent groups of cutting tools is substantially equal to that between other adjacent groups of cutting tools. This arrangement of cutting tools provides a uniform distribution of cutting tools within the at least one section. This contributes to the even wear of the cutting tools. For example, three cutting tools, four cutting tools or five cutting tools form one group of cutting tools.

In an embodiment, the cutting tools of adjacent groups may be arranged offset to one another relative to the circumferential direction. This leads to a further, more uniform distribution of torque at the cutter head.

In an embodiment, the cutting tool tips of the second section have the greatest distance from the rotation axis compared to the cutting tools of first section, the third section and the fourth section, wherein, for example, a ratio of a contour height (the contour height is measured at the middle position of the section and measured radially from the rotation axis of the cutter head or determined as ½ of the contour diameter at the middle position) to a contour length (i.e. the extension of the cutting tool contour determined in a direction parallel to the rotation axis of the cutter head from the cutting tool group located closest to the cutter boom to the cutting tool group arranged farthest away from the cutter boom) is greater than or equal to 0.3.

In an embodiment, the ratio of the contour height and the contour length is greater than or equal to 0.3 and less than or equal to 1.0. In a more preferred embodiment, the ratio of the contour height and the contour length is greater than or equal to 0.4 and less than or equal to 0.85. In an embodiment, the ratio of the contour height and the contour length is greater than or equal to 0.43 and less than or equal to 0.7.

In an embodiment, the third section of the contour line is a substantially straight section.

The above task is further solved by a roadheader having a main body and a cutter boom extending therefrom, wherein the roadheader further comprises two above described cutter heads rotatable about an axis extending transversally relative to a cutter boom longitudinal direction, wherein each cutter head extends from opposite side faces of the cutter boom at a cutter boom end section located opposite the main body. This roadheader has the advantages explained for the cutter head above. Accordingly, it is referred to the above description. The main body of the roadheader includes, for example, a driving unit, a control unit, a pair of endless tracks for propelling the roadheader over the ground, e.g. within a mine, and a conveyor belt, for example, for transport of the mined rock or minerals.

In an embodiment, the cutter boom is pivotable into horizontal and/or vertical direction. This pivoting/swivelling allows a flexible and wide (horizontally and/or vertically) excavation/mining of material. In this case, the roadheader main body comprises a driving unit for driving the horizontal and/or vertical movement of the cutter boom. In one embodiment, the cutter boom is telescopically extendable thereby providing a greater cutting range.

While embodiments of the present invention have been illustrated, and described, it will be understood that changes and modifications may be made therein without departing from the invention in its broader aspects.

The foregoing summary, as well as the following detailed description of the embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the embodiments depicted are not limited to the precise arrangements and instrumentalities shown.

shows a roadheaderwith a main bodysupporting and moving a cutting assembly. The main bodyincludes, for example, a gear box and an on-board control unit. Further, the roadheaderincludes a travelling mechanism including a pair of endless tracksfor propelling the roadheaderover the ground within a mine into a heading direction. The heading directiondefines the front end of the roadheaderand of all its elements. The respective front end is in front when the roadheadermoves into the heading direction. Accordingly, the opposite end of the roadheaderhaving a conveyor beltfor mined rock or mineral transport forms its back end.

The cutting assemblyincludes a cutter boom, which is vertically and horizontally pivotable mounted at the main body. The cutter boomis, for example, pivotable about a first horizontal axisand a second vertical axis. Further, the cutter boommay be telescopically extendable and retractable along a direction of a longitudinal axisof the cutter boom.

Two cutter headsare rotatably mounted to a front end section of the cutter boomopposite the main body. Both cutter headsare jointly driven by a drive gear accommodated within the cutter boomand a joint driven shaft(). Accordingly, the rotation of the two cutter headsis provided about a joint rotation axis. The two cutter headsare mounted mirror-inverted to the front end section of the cutter boom, wherein the mirror plane includes the longitudinal axisof the cutter boom.

Each cutter headincludes a housingwith an outer surface. As one can derive at best from, the outer form of the housingis conical. The embodiment of one cutter headshown inincludes at its outer surfacea number of (e.g. in total) cutting tools (picks). The cutting toolsare numbered, wherein the numbers of the cutting toolsare marked with a circle encircling the respective number to distinguish them from the reference numbers of this description (see). The reference numbers do not have any marking. Each one of thecutting toolsare fixed to the surfaceof the cutter headby means of a holderthat is welded to the outer surfaceof the housing. Each holder includes an opening into which the respective cutting toolis removably mounted. The cutting toolsare mounted such that they point into the rotation direction, wherein the rotation direction is depicted inby arrow. The cutting toolsare inclined with regard to a tangent at the outer surfaceof the housingat the position of the holderby an angle in the range of 40° to 55°.

As can be best derived from, with regard to each cutter heada contour linemay be drawn, wherein the contour lineis defined within the plane of one longitudinal section of the cutter headand contains the positions of all the tipsof the cutting toolswithin this plane when the cutter headprovides a full rotation about its rotation axis. The position of the tipsof the cutting toolsare marked by crossesat the contour line.

In, above each crossthe numbers of the respective three cutting toolsto which the respective crossbelongs too are shown. Accordingly, the cutting toolsare grouped intogroups of three cutting tools, each of which are located at the outer surfaceof the cutter headsuch that they form a virtual circle when the cutter headrotates. Adjacent groups of cutting toolshave a distance ranging from 15 mm to 65 mm, depending on the rock type to be cut and the available cutter motor power (determined in a direction along the contour line).

As one can derive from the structure of the contour line shown in, the distances of the groups of cutting toolsare approximately similar indicating that the cutting tools are uniformly distributed over the outer surfaceof the cutter head. Further, as one can derive from, the cutting toolsof adjacent groups are arranged off-set relative to the circumferential direction.

As indicated in, the contour lineincludes four sections, namely a first section A (closest to the cutter boomand its drive gear), a second section B, a third section C and a fourth section D (farthest from the cutter boom). All the four sections A, B, C and D are substantially straight, wherein the pitches of the second section B, the third section C and the fourth section D are different. The overlapping of the frames depicting the four sections A, B, C and D show, that some pointsof the contour linebelong to two different, directly adjacent sections, for example the pointof the cutting toolswith the numbers,,belong to the first section A and the second section B. The same applies to the pointof the cutting tools with the numbers,,(sections B and C), and the pointof the cutting tools with the numbers,,(sections C and D). In this embodiment, the pitch of the first section A is −40°, the pitch of the second section B is 0° (i.e. the second section B of the contour lineruns horizontally, parallel to the rotation axis), the pitch of the third section C (main section) is 30° and the pitch of the fourth section D is 40°, wherein the pitch is measured in relation to the rotation axisof the cutter head.

The contour height H at section B (i.e., the distance of section B from the rotation axis) is, for example, 690 mm and the contour length L is, for example, 820 mm (see). Accordingly, the ratio of the contour height and contour length is 0.84.

A second embodiment of a cutter head is depicted inby means of its contour line′ drawn through points′ representing the position of cutting tool tips within one longitudinal section of the respective cutter head considering one full rotation of this cutter head. The second embodiment includes a longer first section A′ compared to the first section A of the first embodiment (see). Accordingly, the third section C′ is shorter than the third section C of the first embodiment. In this embodiment, the pitch of the first section A′ is 32°, the pitch of the second section B′ is 0°, the pitch of the third section C′ (main section) is 32° and the pitch of the fourth section D′ is 53°. Further, contour height at section B′ is, for example, 650 mm and the contour length is, for example, 940 mm. Accordingly, the ratio of the contour height and contour length is about 0.7. The advantage of a cutter head having such contour line′ is that, optimum cutting parameters at all periods of the cutting process can be achieved; which ends up in optimum cutting rates at minimum and equal wear of cutting tools, reduced maintenance, and optimum cutting behavior, which means minimum vibration of cutting head, cutting boom and cutting machine.

Although the present embodiment(s) has been described in relation to particular aspects thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present embodiment(s) be limited not by the specific disclosure herein, but only by the appended claims.