Disk Cutter

This Non-Provisional Patent Application is a continuation of and claims priority to U.S. patent application Ser. No. 18/348,654, filed Jul. 7, 2023, allowed, which claims priority to U.S. patent application Ser. No. 17/770,830 filed on Apr. 21, 2022, now U.S. Pat. No. 11,802,481, issued Oct. 31, 2023, which is a U.S. national phase of International Patent Application No. PCT/EP2020/083296, filed on Nov. 25, 2020, which claims the benefit of United Kingdom Patent Application Nos. 1917708.8, filed on Dec. 4, 2019 and 2005020.9, filed on Apr. 6, 2020, each of which is incorporated herein by reference in its entirety.

The present disclosure relates to a disk cutter used in mining and excavation machines or in trenching machines. In particular, it relates to a disk cutter with cutting elements comprising superhard materials, such as polycrystalline diamond.

Many types of rock formations are available around the world as large deposits, commonly known as slabs. Various types of mining equipment are deployed in above ground quarries in order to extract the slabs from the ground. The slabs are retrieved using specialist equipment, typically dragged from their resting place by large and very powerful vehicles. Rock slabs may weigh up to 40 tons (40,000 kg). Processing, such as polishing, may take place on site, or alternatively the slabs may be transported off site for cutting into appropriately sized pieces for domestic and industrial use.

The same equipment used above ground may not always be directly usable within the confined space of a subterranean mine.

It is an object of the invention to provide a compact and versatile cutting assembly to facilitate the mining and extraction of geometrically or non-geometrically shaped blocks of specific rock formations, and one that may be used above or below ground.

The Applicant's co-pending applications WO 2019/180164 A1, WO 2019/180169 A1, WO 2019/180170 A1 disclose a cutting assembly comprising a circular disk cutter, which is moveable between horizontal and vertical cutting orientations. Cylindrical cutting elements and a corresponding quantity of tool holders are arranged and seated around a circumferential surface of the disk cutter. Each tool holder is at least partially laterally offset with respect to the circular body. The disadvantage of such an arrangement is that it still requires substantial cutting forces in order to cut through rock formations.

It is an object of the invention to provide a cutting assembly with reduced cutting forces.

According to a first aspect of the invention, there is provided a disk cutter comprising a cutter body, a plurality of tool holders and a plurality of cutting elements mounted to the tool holders, wherein the tool holders and cutting elements are provided in at least one set about the cutter body, each set comprising two or more tool holders and two or more cutting elements, the two or more cutting elements being arranged in a pre-determined sequence of configurations on the tool holders, the tool holders all facing in the same direction.

The disk cutter may comprise multiple sets around a circumferential surface of the cutter body.

The multiple sets may be identical. Alternatively, the multiple sets may be non-identical.

The disk cutter may comprise three or more tool holders in a set.

The disk cutter may comprise four tool holders in a set.

The disk cutter may comprise a single cutting element in one or more of the tool holders. In this embodiment, the single cutting element is optionally mounted centrally on the tool holder.

The disk cutter may comprise two cutting elements in one or more of the tool holders. In such an embodiment, the two cutting elements may be arranged side-by-side adjacent to each other on the tool holder. Alternatively, the two cutting elements may be arranged spaced apart from each other on the tool holder. Optionally, the two cutting elements are arranged spaced apart with a recessed channel in between then.

The cutting element may be a polycrystalline diamond compact (PDC). Optionally, the PDC has a triple chamfer.

Preferably, the tool holder comprises a body portion and a pair of spaced apart legs. The tool holder optionally tapers inwardly from a first end, proximate the or each cutting element, towards a second end.

The cutter body may comprise a series of slots.

According to a second aspect of the invention, there is provided a trench cutter comprising a disk cutter in accordance with the first aspect. Optionally, the cutter body has a diameter in the range of 900 to 1200 mm. Preferably, the cutter body has a thickness in the range of 20 to 30 mm. Preferably, the disk cutter has an effective cutting width of around 60 mm.

According to a third aspect of the invention, there is provided a disk cutter comprising a cutter body, a plurality of tool holders, a plurality of cutting elements, at least one cutting element mounted to at least one tool holder, the plurality of tool holders and plurality of cutting elements being provided along a peripheral surface of the cutter body, the tool holders and cutting elements provided in at least one set about the cutter body, each set comprising two or more tool holders and two or more cutting elements arranged in a pre-determined sequence of configurations, wherein the cutter body comprises at least one light-weighting aperture.

The disk cutter comprise multiple sets around a peripheral surface of the cutter body.

The multiple sets may be identical. Alternatively, the multiple sets may be non-identical.

The disk cutter may comprise three or more tool holders in a set.

The disk cutter may comprise four tool holders in a set.

The disk cutter may comprise a single cutting element in one or more of the tool holders. In this embodiment, the single cutting element is optionally mounted centrally on the tool holder.

The disk cutter may comprise two cutting elements in one or more of the tool holders. In such an embodiment, the two cutting elements may be arranged side-by-side adjacent to each other on the tool holder. Alternatively, the two cutting elements may be arranged spaced apart from each other on the tool holder. Optionally, the two cutting elements are arranged spaced apart with a recessed channel in between then.

The cutting element may be a polycrystalline diamond compact (PDC). Optionally, the PDC has a triple chamfer.

Preferably, the tool holder comprises a body portion and a pair of spaced apart legs. The tool holder optionally tapers inwardly from a first end, proximate the or each cutting element, towards a second end.

In the drawings, similar parts have been assigned similar reference numerals.

Referring initially to, a cutting assembly for slicing into natural formationsunderground is indicated generally at.

The cutting assembly forms part of a long wall mining system, commonly found in underground mines. The cutting assembly is a substitute for known shearer technology, which operates on a mine floor, amidst a series of adjustable roof supports. As the shearer advances in the direction of mining, the roof supportsare positioned to uphold the mine roofdirectly behind the shearer. Behind the roof supports, the mine roofcollapses in a relatively controlled manner. Typically, a gathering arm collects mined rock at the cutting face and transfers it onto a conveying system for subsequent removal from the mine.

As indicated in, the cutting assemblycomprises a base unit, a pair of spaced apart support armsextending from the base unit, a drive spindleextending between and rotatably mounted to the pair of moveable support arms, and a plurality of disk cuttersfixed about the drive spindle.

In a second embodiment, indicated in, a single support armextends from the base unit. The drive spindleis supported centrally by the single support arm, and the plurality of disk cuttersis mounted to the drive spindle, distributed either side of the single support arm.

In an alternative embodiment, not shown, only a single disk cutteris used.

Preferably, the or each disk cutteris mounted at is centre (i.e. centrally) about the drive spindle. However, this is not essential, and the or each disk cuttermay alternatively be mounted off-set from its centre about the drive spindle. Optionally, a combination of the two arrangements could be used instead. For example, when multiple disk cuttersare used in a series, i.e. in parallel next to each other along a drive spindle, alternating disk cuttersmay be mounted centrally about the drive spindle. Each centre of the remaining disk cuttersmay be radially off-set from the point at which the disk cutteris mounted about the drive spindle. Other combinations are envisaged.

The base unitfunctions as a transport system for the disk cutter. The base unitis moveable to advance and retract the disk cutterinto and out of an operational position, in close proximity to the rock formationto be cut. The speed at which the base unitmoves closer to the rock formationis one of several variables determining the feed rate of the cutting assemblyinto the rock formation. The base unit(in concert with the roof supports) is also moveable sideways, from left to right and vice versa, along the long wall of the rock formationto be mined.

Each support armis configured to be moveable into a first and a second cutting orientation. In the first cutting orientation, best seen in, the drive spindleis horizontal. As a result, cuts in the rock formationmade by the disk cutterare correspondingly vertical. In the second cutting orientation, best seen in, the drive spindleis vertical. Consequently, cuts in the rock formationmade by the disk cutterare correspondingly horizontal. First and second cutting orientations are possible with either first or second embodiments mentioned above.

Optionally, the support arm(s)may also be moveable such that the drive spindleis operable in any cutting orientation between the aforementioned vertical and horizontal, though this is not essential. The support arm(s)may alternatively be configured such that they are moveable between the first and second cutting orientations but only fully operational (i.e. the disk cutter(s) to rotate in order to facilitate cutting or pulverising of the rock) in the first and second cutting orientations.

Each support armis moveable between a first operative position and a second operative position, in optionally each of the first and second cutting orientations, according to the depth of cut required. This is indicated by double end arrow A in. For example, in the first operative position, the drive spindleis lowered so as to be in close proximity to the mine floorand in the second operative position, the drive spindleis raised so as to be in close proximity to the mine roof.

Optionally, each support armmay have a first arm portion connected to a second arm portion by a pivot joint (or alternatively, a universal joint), each first and second arm portion being independently moveable relative to each other. This arrangement augments the degrees of freedom with which the cutting assemblymay operate and advantageously improves its manoeuvrability.

The drive spindleis driven by a motor to rotate at a particular speed. The power of the motor is typically between 20 and 50 KW per disk cutter, depending on the type of disk cutterselected and the cutting force required.

Turning now to, in an embodiment of the invention, the disk cuttercomprises a generally circular bodyand a plurality of cutting elementsarranged peripherally around the circular body. Rotation of the drive spindlecauses a corresponding rotation of the disk cutter. The disk cutterneed not be generally circular, for example, depending on its size, an octagonal shaped cutter could approximate a generally circular disk cutter. Accordingly, the disk cuttermay be hexagonal, octagonal, decagonal etc, or indeed have any number of circumferentially extending sides. More information about the bodyis provided further below.

In a preferred embodiment, a plurality of disk cuttersis arranged on the drive spindle. Typically, six or more disk cuttersmay be provided. The disk cuttersare preferably regularly spaced apart along the length of the drive spindle, between the pair of spaced apart support arms, or either side of the support arm, depending on the embodiment.

The spacing of the disk cuttersis selected according to the depth of cut required and the mechanical properties, e.g. Ultimate Tensile Strength (UTS), of the rock formationbeing cut in order to optimise the specific cutting energy, which will dictate the required power consumption. The aim is to achieve conditions under which the cut material will breakout under its own weight. For example, for a 0.4 m depth of cut in Kimberlite, the ideal spacing between adjacent disk cutters is around 0.3 m. However, this can be increased or decreased depending on the force required for breakout. Preferably, the spacing is adjustable in-situ and may be an automated process or a manual process. The spacing may be remotely adjustable, for example from an operations office above ground. A wedge shaped tool may be used to apply such a breakout force, to assist in rock breakout.

The disk cuttersare spaced apart by a gap measuring between preferably 0.01 m and 2 m, more preferably between 0.01 m and 0.5 m. Yet more preferably, the disk cutters arespaced apart by a gap measuring between 10 cm and 40 cm.

The circular bodyof the disk cutteris typically made from steel and has a diameter of approximately 1000 mm and a thickness (measured axially, also considered to be a lateral extent for subsequent descriptions) of approximately 10 to 30 mm. Realistically, such a diameter enables a depth of cut of up to 400 mm. The circular bodyhas a shaft diameter of between 60 mm and 100 mm, and is sized and shaped to receive the drive spindle.

The diameter (or effective diameter in the case of non-circular disk cutters) and thickness of the disk cutterare selected appropriately according to the intended application of the cutting assembly. For example, cable laying applications would require a disk cutterwith a smaller diameter. Robotic arm angle grinders would require a yet smaller diameter. Tunnelling applications though would require a disk cutterwith a significantly greater diameter and would be adapted accordingly.

According to the invention, the disk cutteralso comprises a plurality of tool holdersfor each receiving at least one cutting element. In this embodiment, there is a repeating set of four tool holdersand seven cutting elements. There are forty-two PDC cutting elementsin total. Each set is repeated identically about the circular body. In each set, there are four different spatial configurations of tool holderand cutting element, as explained in more detail below. When arranged in sequence, one behind the other in the direction of rotation of the disk cutter, the required cutting force of the disk cutteris significantly reduced.

In each set, the tool holders remain facing the same forward direction, towards the direction of rotation. It is the arrangement of cutting elements that changes from one tool holder to the next within the set. It is the pre-determined sequence of cutting elements that is advantageous and distinct from the prior art.

Non-identical sets located about the circular bodymay be used.

Not all sets have to include tool holders with any cutting elements. They could simply be ‘blanks’ without cutting elements.