ROTARY CUTTING HEAD WITH FLUID SUPPLY DUCTING

FIELD OF INVENTION

The present invention relates to a rotary cutting head for a cutting machine and in particular, although not exclusively, to a cutting head adapted to provide a flow of a fluid to a set of spray nozzles mounted at a peripheral portion of the cutting head, that in turn produce fluid jets to a peripheral cutting region of the head.

BACKGROUND ART

A variety of different types of cutting machine have been developed for the many different applications of rock cutting in a mine environment such as cutting drifts, tunnels, subterranean roadways and the like. Undercutting machines are typically suitable for cutting hard rock by utilising an undercutting principle in which rotatable cutters are forced and dragged against the rock to create a groove that facilitates overcoming the rock tensile strength.

Typically, an undercutting machine comprises a set of roller cutters mounted at a cutting head that may be raised upward in the undercutting mode. Each roller cutter comprises a cutter ring or disc rotatably mounted at a support shaft that is capable of rotation about its central axis. The cutter rings are wear parts and require interchange at regular intervals as they become worn under the aggressive contact with the hard rock.

Existing mining and excavation machines are typically provided with a water spraying mechanism that involves a continuous or intermittent supply of water towards the cutting region to firstly cool the cutting teeth and secondly assist with dust suppression. U.S. Pat. No. 3,563,324 discloses a rotary cutting machine having a plurality of cutting teeth mounted at a periphery of a cutter body. A plurality of atomising nozzles are mounted at the cutter body so as to direct a jets of water towards cutting teeth when cutting into the rock. Similarly, U.S. Pat. No. 4,296,824 discloses a set of nozzles mounted towards the cutting region of a cutter head to provide a continuous stream to the cutting zone that entrains the cuttings rearwardly away from the cutting zone. U.S. Pat. No. 4,721,341 discloses a cutting head having an internally fed spraying means in which water is fed at high pressure to a set of spray nozzles positioned adjacent to the cutting teeth.

However, existing arrangements are disadvantageous for a number of reasons. In particular, accelerated teeth wear and inefficient cutting typically result from a non-optimised supply of fluid (i.e. water) to the teeth and the region of rock that is being cut. Effectively, the cutting teeth (alternatively referred to as cutting picks or buttons) in addition to cutting new rock, grind already cut rock to smaller fines which is undesirable. Additionally, existing arrangements typically involve a complex fluid supply necessitating multiple sealed moving interfaces, valves and the like that increase servicing and maintenance and the risk of fluid leakage. Additionally, nozzles of existing arrangements can be susceptible to blockage from the dust and debris produced when cutting.

Accordingly, what is required is a cutting head that addresses these problems.

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide a rotary cutting head for a cutting machine adapted for an efficient cutting action and to minimise accelerated wear of cutting teeth (cutting picks or buttons) due to undesirable regrinding of already cut rock. It is a specific objective of the present invention to provide and direct a flow of a fluid into the path of the cutting edges or teeth so as to provide a purging or cleaning of the cutting region in addition to providing cooling of the cutting edges or teeth.

It is a further objective of the present invention to provide a simple, robust and reliable system to supply a (cleaning/cooling) fluid to a cutting region of a rotary cutting head so as to minimise servicing, maintenance and the risk of fluid leakage. It is a yet further objective to minimise the number of component parts of the cutting head and in particular the fluid supply system to effectively reduce the requirement for and reliance on seals and valves at one or moving interfaces.

It is further objective to provide a fluid supply arrangement in which spray nozzles at the cutting region are effective to provide an intermittent selective fluid supply to the cutting edges or teeth whilst being positionally located to minimise the risk of blockage or damage to the nozzles during cutting. It is a further specific objective to provide a rotary cutting head having a plurality of cutting units that themselves or the component parts of which are convenient to interchange for servicing and maintenance purposes whilst minimising disruption to any sealed interfaces.

The above objectives are achieved via a rotary drill head in which a rotatable support frame mounts a plurality of peripheral cutter units (each with a cutter disc optionally carrying cutting buttons) and having at least a first set of spray nozzles positionally mounted at the support frame adjacent to each cutter unit so as to direct a fluid jet to a radially outer region of each of the discs (located radially outside a peripheral portion of the support frame) that define a radially outermost perimeter of the cutting head. In particular, the nozzles of at least the first set are positioned so as to direct a fluid jet into the rotating path of selected cutter discs and in particular into the region of a cut groove (formed into the rock by the cutting action of the head) at the very region radially outermost cutting portions (selections) of the discs that are effective to cut the rock. This fluid spray is effective primarily to flush fines from around the region of those active cutting regions (i.e. edges or buttons) so as to avoid regrinding of cut rock, and in turn maximise cutting efficiency and minimise button wear. By positioning the nozzles at the rotatable support frame and not at the cutter units (and in particular the cutting discs), the nozzles are better shielded from abrasive contact with the rock during cutting.

Additionally, the fluid supply pathway (via internal ducting) does not extend through the independently rotatable cutting discs and therefore the number of sealed moving interfaces (that form part of the fluid supply pathway within the rotatable support frame) is minimised. In turn, the present rotary cutting head minimises a requirement for seals, gaskets and the like so as to provide a simple, reliable and robust construction. The present rotary cutting head therefore is adapted for minimised servicing and maintenance together with providing a reduced risk of fluid leakage. As will be appreciated, the nozzles of the first set are also effective to provide cooling of the edges or buttons which is advantageous to minimise operating temperatures and extend the operational service lifetime of the discs.

The present rotary cutting head is further adapted to provide a selective fluid supply to selection of the cutter units in that not all cutter units are supplied with fluid at any one time and only those cutter units having cutting discs that are active (i.e., cutting) receive the fluid. Additionally, the present invention via the specific positioning of the nozzles directs the fluid jet to a selection or region only of the cutting edges or buttons (at those selected cutting discs) to further optimise the volume of fluid delivered to the cutting region and further enhance the efficiency of the cutting and fluid cleaning and cooling processes.

Additionally, the present rotary cutting head is adaptable to provide an intermittent supply of fluid via fluid delivery arrangements comprising ducts, slots, holes or bores that minimise a requirement for sealing interfaces (between moving parts of the rotary cutting head).

According to a first aspect of the present invention there is provided a rotary cutting head for a cutting machine comprising: a rotatable support frame having a radially inner region and a radially peripheral portion and being rotatably coupled to a rotation drive unit; a plurality of cutter units mounted at or towards the peripheral portion, each of the units having a cutter disc rotatably mounted at a cutter hub, a radially outer portion of each of the discs by rotation of the discs configured to abrade rock and create a cut groove therein; each of the discs being rotatable relative to the rotatable support frame via each respective hub; a plurality of fluid supply ducts extending at the support frame and provided in fluid communication with a first set of nozzles to deliver a fluid to the discs; the nozzles mounted at the support frame so that the discs are capable of independent rotation relative to the nozzles; and the nozzles positionally mounted to direct a fluid jet to a region of the discs that are located radially outside of the peripheral portion of the support frame and that define a radially outermost perimeter of the cutting head.

Optionally, the cutting head further comprises a fluid flow director to direct a flow of fluid to a selection only of the nozzles at the peripheral portion of the support frame. Optionally, the fluid flow director is configured to provide fluid flow to a selection of the nozzles where the selection of nozzles includes nozzles positioned at the support frame within an angular segment of 100° to 200°, 130° to 170° or 140° to 160°. Such an arrangement is advantageous to minimise a volume of fluid utilised for the cleaning and cooling function at the cutting region and to avoid flooding of the cutting region.

Optionally, the fluid flow director comprises a disc located at the radially inner region of the support frame having a plurality of holes and/or slots extending over an angular segment of the disc in a range 100° to 200°, 130° to 170° or 140° to 160°. Such an arrangement is advantageous over alternative valve based arrangements that necessitate multiple sealed interfaces. Accordingly, the present arrangement is beneficial to minimise the number of component parts and to provide a reliable assembly that is convenient to manufacture, install and maintain.

Optionally, the cutting head comprises a fluid flow interrupter to provide an intermittent fluid flow to the nozzles. Optionally, the fluid flow interrupter comprises a disc located at the radially inner region of the support frame. Preferably the interrupter is configured to manipulate a fluid flow to provide a pulsed fluid flow to the nozzles according to predetermined timing intervals.

Preferably, the fluid supply ducts extend internally within the support frame in a direction radially outward from the inner region to the peripheral portion. Preferably, the entire length of the fluid supply ducts are mounted internally in the cutting head. Optionally, the ducts include bores, channels or conduits formed as bores extending within solid components. Optionally, the fluid supply ducts may comprise tubing, hosing or other supply conduits mounted internally within the cutting head between external surfaces of the cutting head. Such an arrangement is advantageous to avoid damage to the supply ducts during cutting as the cutting machine is operational in a confined environment where contact with rock or other apparatus or machinery may damage the supply ducts.

Preferably, the cutting head further comprises a second set of nozzles in fluid communication with the fluid supply ducts and mounted at the support frame at respective positions to direct a fluid jet onto the hubs. Such an arrangement is advantageous to provide a cooling flow of fluid to the nubs so as to effectively cool internal components of the cutter units including in particular oil, grease, bearings and the like.

Optionally, the first set and the second set of nozzles are mounted at respective shrouds located at the peripheral portion of the support frame and positioned between each of the hubs in a circumferential direction. Optionally, each nozzle of the first set is positioned at each shroud at a position radially outside of each nozzle of the second set. Such an arrangement is advantageous to minimise the length of spray created by the nozzles when delivered to the cutting edges or buttons (in a forward direction) and the hubs (in a rearward direction). As such, the present invention is advantageous to maximise efficiency of the use of a cleaning and cooling fluid and to avoid wastage and flooding of the cutting region.

Optionally, each shroud is detachably mountable at the support frame. Accordingly, each shroud may be conveniently detached and reattached at the support frame if cleaning or other maintenance of the nozzles is required without disrupting the cutting units and remaining components of the cutting head.

Optionally, each disc is not independently rotatably driven relative to the drive unit that drives rotation of the support frame. Preferably, each disc is configured to be rotatably driven exclusively via rotation of the support frame by the drive unit. Accordingly, the present cutting head is beneficial to provide an effective cutting action whilst minimising the drive components, the weight of the cutting machine and the servicing and maintenance of the cutting head. Preferably, the cutting head further comprises a gear box arrangement having a drive shaft, the support frame rotatably mounted and driven via the drive shaft.

Optionally, the cutting head may comprise in the range 5 to 20 cutter units mounted at the peripheral portion. Preferably, each of the cutter units are identical including the corresponding cutter discs and hubs.

Optionally, the cutting head may comprise a plurality of cutting buttons mounted at the radially outer portion of each of the discs, the nozzles positionally mounted to direct the fluid jet to a selection of the buttons of the discs that are located radially outside of the peripheral portion of the support frame that define the radially outermost perimeter of the cutting head. Preferably, the cutting buttons comprise a first material and the cutter discs comprise a second material, the material of the cutting buttons being harder than the material of the discs.

Optionally, a rotational axis of each of the respective discs is aligned generally with the rotational axis of the support frame. Preferably, each rotational axis of each cutter disc is aligned approximately parallel with the rotational axis of the support frame. Optionally, each rotational axis of each cutter discs is aligned to be inclined radially outwardly from the rotational axis of the support frame at an angle in the range 1 to 15°.

According to a further aspect of the present invention there is provided a cutting machine comprising at least one cutting head as claimed herein. Optionally, the cutting machine is an undercutting mining machine, a continuous mining machine, an electrically operated mining machine and/or a mining machine having one, two, three, four or more cutting heads mounted at distal ends of booms or arms capable of pivoting movement relative to a main body or chassis of the machine. Optionally, the machine may comprise a fluid reservoir, fluid pump, supply hoses and valves to provide a source of a fluid to the cutting heads.

BRIEF DESCRIPTION OF DRAWINGS

A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a mobile undercutting mining machine suitable for creating tunnels and subterranean roadways having a pair of forward mounted pivoting cutting arms each mounting a rotary cutting head according to one aspect of the present invention;

FIG. 2 is a underside view of one of the rotary cutting heads of FIG. 1 with selected components removed for illustrative purposes in which a plurality of cutter units are mounted at a peripheral portion of a rotatable support frame of the head according to a specific implementation of the present invention;

FIG. 3 is a side elevation view of the cutting head of FIG. 2;

FIG. 4 is an underside perspective view of the rotary cutting head of FIG. 2;

FIG. 5 is a magnified front view of a selection of the cutter units of the cutting head of FIG. 2 in which each unit comprises a hub that mounts an independently rotatable cutting disc;

FIG. 6 is a magnified rear view of the selected cutting units of the cutting head of FIG. 2;

FIG. 7 is a cross-sectional view through A-A of the rotary cutting head of FIG. 2 having an internal fluid supply arrangement to deliver a cleaning/cooling fluid to the cutting discs according to a specific implementation of the present invention;

FIG. 8 is a perspective view of a shroud positioned adjacent to the cutting discs of the rotary head of FIG. 2 that mounts respectively a first and a second spray nozzle to direct a fluid jet onto a region of a cutting disc and a support hub of the rotary head of FIG. 2;

FIG. 9 is a cross-sectional view through B-B of the shroud of FIG. 8;

FIG. 10 is a front end view of the shroud of FIG. 8;

FIG. 11 is a rear end view of the shroud of FIG. 8; and

FIG. 12 is a plan view of a fluid director disc mountable at a radially inner region of the rotary cutting head of FIG. 2 to provide a selective fluid supply to the cutting discs.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

A fluid (e.g., water) supply system according to the present invention is capable of delivering a fluid to a cutting region of a rotary cutting head mountable to a variety of different types of cutting or mining machines. A specific implementation of a rotary cutting head in accordance with the present invention is described with reference to an undercutting mining machine for creating tunnels and subterranean roadways as a plurality of rotating heads are slewed laterally outward and raised in the upward and downward direction during forward cutting. The rotary cutting head is adapted specifically to deliver a fluid to the cutting region of the head so as to enhance cutting efficiency and reduce the rate of wear of cutting edges or teeth formed at a peripheral portion of the cutting head.

Referring to FIG. 1, a cutting machine 10 is configured to cut into rock within a mining environment to create drifts, subterranean roadways and the like so as to form an underground mine network. Machine 10 is configured for operation in an undercutting mode in which a plurality of rotatable roller cutter units 13 may be forced into the rock to create a groove or channel and then to be pivoted vertically upward so as to overcome the reduced tensile force immediately above the channel and break the rock. Accordingly, the cutting machine 10 is optimised for forward advancement into the rock using less force and energy typically required for conventional compression type cutters that utilise cutting bits or picks mounted at rotatable heads.

Machine 10 comprises a main frame 11a (or chassis) that mounts a sled 11b capable of sliding forward and aft along a forward region of the sled 11a. A pair of support arms 12 are mounted at a forward region of sled 11b and are configured with parts to pivot independently via a generally horizontal pivot axis and a generally vertical pivot axis. A respective rotary cutting head 15 is mounted at the distal end of each arm 12 and by rotation about the respective horizontal and vertical pivot axes is capable of being raised in a vertical plane (up and down) and to be slewed laterally in a horizontal plane (side-to-side). Each cutting head 15 mounts a plurality of cutter units 13, with each unit 13 rotatably mounting a respective cutter disc 14 (otherwise referred to as a roller cutter or cutting ring). As will be appreciated, machine 10 further comprises additional components associated with conventional undercutting apparatus including in particular an electric motor, jacking legs, tracks etc. The lateral slewing movement of each arm 12 is provided by selective actuation of a first pair of externally mounted hydraulic cylinders 16, 17 and an internally mounted hydraulic cylinder 18, with each of the three cylinders being configured to control one of the two arms via linear extension and refraction of the piston shafts as will be appreciated.

Referring to FIGS. 2 to 4, each rotary cutting head 15, when viewed in plan (or at a cross section perpendicular to a rotational axis 24 of the head 15) may be considered to be a wheel or disc having a radially inner region 21 and a radially outer peripheral portion indicated generally by reference 20. Peripheral portion 20 is generally circular around axis 24. Each head 15 comprises a support frame indicated generally by reference 23 that represents the main body of head 15. Support frame 23 according to the specific implementation is a multi-component support structure comprising for example a series of panels, plates, struts, assemblies and attachment elements (i.e. bolts and/or screws) formed together as a unitary body to support the cutter units 13 and to withstand the significant loading forces encountered at the head 15 during cutting.

As illustrated in FIGS. 2 and 4, the cutter units 13 are mounted at the peripheral portion 20 of support frame 23 to define generally a ring of cutter units 13 extending around axis 24. The cutter units 13 are mounted at the peripheral portion 20 of frame 23 such that the outer region of each cutter disc 14 extends radially beyond peripheral portion 20. Accordingly, a diameter (or radius) of each head 15 is defined in part by the radial outermost portion of each disc 14. In particular, each disc 14 carries a plurality of cutting buttons 19 (alternatively referred to as cutting picks or teeth) formed from a high abrasion resistant material as will be familiar to those skilled in the art. Buttons 19 project radially outward from a radially outer portion or perimeter of each disc 14. Accordingly, a region indicated generally by reference 28 of each of the discs 14 (and/or a selection of the buttons 19) project radially beyond the peripheral portion 20 of support frame 23. It is this region 28 (and selection of buttons 19) that represent the effective cutting portion of each cutter unit 13.

As will be understood, each of the discs 14 is mounted at a respective cutter hub 25 that represents a majority component of each cutter unit 13. Each hub 25 comprises internally mounted bearings to allow free rotation of each disc 14 about a rotational axis 26 extending longitudinally through each generally cylindrical hub 25. Each disc 14 is not positively or power driven at each hub 25 but is in turn rotated about axis 26 (of each respective cutter unit 13) and central axis 24 (of the respective cutting head 15) via the powered/driven rotation of head 15 by a drive unit 55 and gear box 22 as mounted at machine 10 and in particular each arm 12. That is, each head 15 is configured for rotation about axis 24 in direction R₁so as to induce a corresponding rotation in direction R₂of each disc 14 that is pressed in contact with the rock during cutting. The region 28 of each disc 14 (i.e., selection of cutting buttons 19) that extends radially beyond a radially outermost peripheral surface 27 of head 15 represent the ‘active’ cutting region and buttons to provide the cutting action at any specific time period as each disc rotates by direction R₂and R₁about each respective axis 26, 24.

The peripheral portion 20 of each head 15 is defined by a plurality of shrouds illustrated in isolation within FIGS. 8 to 11. Each shroud 40 comprises a generally ‘hammer-head’ shaped main plate 42 from which extends laterally a mounting flange 41 having through bores 43 to receive attachment bolts to mount each shroud 40 at head support frame 23. The shrouds 40 represent radially outermost components of each head 15 and are positioned, in a circumferential direction, between each respective cutter unit 13 so to at least partially envelop or nestle against neighbouring cutter units 13 at a position immediately behind each cutter disc 14. In particular, the ‘hammer-head’ shaped end of each plate 42 is positioned in the axial direction (of axis 26) between disc 14 and hub 25 such that laterally outward regions 42a of a single plate 42 are positioned immediately behind cutter disc 14 of two neighbouring cutter units 13. An end surface of plate 42 that extends between regions 42a represents the radially outermost surface 27 of the head 15 at the head peripheral portion 20.

A recess portion 30 is indented into a first forward facing planar surface 31 of plate 42. A first nozzle 29 is mounted internally within plate 42 such that a spray tip of nozzle 29 is positioned at recess portion 30. Accordingly, with fluid supplied to nozzle 29, a fluid jet is capable of being directed from nozzle 29 forwardly and outwardly from recess portion 30 onto a part of a respective disc 14. A corresponding recess portion 34 is formed within a second rearward facing planar surface 32 of plate 42 with surface 32 orientated to be facing cutter hubs 25. A second nozzle 33 is mounted within plate 42 so as to have a spray tip that emerges within the recess portion 34 to be capable of producing a fluid jet in a rearward direction and outwardly from plate 42. The forward facing first recess portion 30 and the first nozzle 29 are positioned so as to be aligned along a direction (indicated by line 52) transverse to a longitudinal axis 51 of plate 42 at an angle in a range 75 to 85°. Accordingly, each of the first nozzles 29 is orientated so as to direct the fluid jet exclusively onto the region 28 (selection of buttons 19) at the radially outermost region of head 15. Moreover, the nozzles 29 are positioned adjacent each disc 14 so as to direct the fluid jet onto the button selection 28 as each disc 14 rotates in direction R₂. That is, the spray jet from each nozzle 29 may be considered to flow in a clockwise direction whilst each disc 14 is configured to rotate in an anti-clockwise direction. With the head 15 positioned against the rock during cutting, each nozzle 29 directs the fluid jet into the as-formed groove that is cut into the rock by the button selection 28 and in particular into the clearance space within the as-formed groove. This is beneficial to primarily flush the cut groove and clear rock pieces and fines to avoid grinding and regrinding of the cut material.

Accordingly, the cutting efficiency of the present arrangement is enhanced. The position and configuration of each of the first nozzles 29 also provides a secondary cooling of the buttons 19 and the peripheral edge of each disc 14 during cutting. This together with the flushing of cut rock and fines minimises abrasive wear of the buttons 19 and discs 14 so as to extend their service lifetime. In a direction of head axis 24 (and a respective cutter unit axis 26), each nozzle 29 is positioned slightly axially rearward relative to each disc 14 and the buttons 19 within the selection 28. As such, nozzles 29 and recess portions 30 are further orientated to be transverse to head axis 24 (and the respective cutter unit axis 26) so as to direct the fluid jet axially forward onto the buttons 19 within selection 28.

Each of the second nozzles 33 and respective second recess portions 34 are aligned in a direction illustrated by line 58 that extends perpendicular to the main length or axis 51 of plate 42. That is, each second nozzle 33 is aligned transverse to each first nozzle 29 at each plate 42 with an angle between the respective nozzles 29, 33 (as defined by directional lines 52, 58 respectively) being in a range 5 to 15°. Each of the second nozzles 33 and respective recess portions 34 are aligned in the direction of head axis 24 and cutter unit axis 26 to be generally rearward facing at plate surface 32. Accordingly, the fluid jet produced from each nozzle 33 is directed rearwardly from surface 32 and onto a cutter hub 25. Accordingly, each hub 25 is provided with a cooling supply of fluid. Such an arrangement is advantageous to cool oil and grease internally within each hub 25 that in turn provides a controlled cooling of the internal hub components (i.e., bearings etc.).

The fluid supply pathway to each of the first and second nozzles 29, 33 will now be described with reference to FIGS. 7 to 12. Referring initially to FIG. 7, cutting head support frame 23 comprises generally a forward facing annular face 37 and a rearward facing annular face 38. A central hub 35 is mounted at the radially inner portion 21 of head 15 to represent an inner frame part of the head 15. A peripheral frame assembly 59 provides a radially outer region to which is mounted each of the cutter units 13 and shrouds 40. Each head 15 comprises internal ducting extending radially between the inner hub 35 and outer assembly 59. In particular, a central supply duct 57 (indicated schematically) provides a means of transferring fluid from a source reservoir into head 15. Referring to FIG. 7 in combination with FIG. 12, a distributor disc 60 is mounted at hub 35 to be centred on axis 24. Disc 60 comprises a series of discreet holes or slots 63 that extend over an angular distance towards a perimeter 62 of disc 60. According to the specific implementation, disc 60 comprises eight slots extending between a first endmost slot 63a and a second endmost slot 63b. An angle α between the respective end slots 63a, 63b is in a range 140 to 160°. Disc 60 is positioned adjacent to central supply duct 57 via a central boss assembly 61 mounted at inner hub 35 such that fluid is capable of flowing from supply duct 57, through slots 63 and into ducting 36 via port 45. Boss assembly 61 comprises a series of annular discs, plates and seals so as to securely mount disc 60 and provide a fluid tight seal for the transfer of fluid into ducting 36 (within support frame 23).

Referring again to FIG. 7, hub 35 comprises a plurality of feed ducts illustrated generally by reference 36 that extend radially from hub 35 to outer assembly 59. According to the specific implementation, each head 15 comprises a plurality of ducts 36 corresponding to the number of cutter units 13, which according to the present embodiment, is 12. Each feed duct 36 comprises a radially inner receiving port 45 that interfaces with a respective disc slot 63 so as to allow a supply of fluid from central supply duct 57 into feed duct 36. Fluid then flows generally radially outward through feed duct sections 36a, 36b, 36c and 36e. Feed duct 36 further comprises various plugs 36f, 36d required for manufacturing convenience. The feed supply of fluid emerges from head peripheral assembly 59 at supply port 46.

Referring to FIGS. 8 to 11, each shroud 40 comprises a fluid delivery port 44 provided at rearward facing planar surface 32. A delivery duct 48 extends axially within plate 42 being centred on axis 51 between port 44 and a pair of outlet ports 49, 50. A first outlet port 49 is provided in fluid communication with second nozzle 33 and a second outlet port 50 is provided in fluid communication with first nozzle 29, with the ports 49, 50 being located toward one end of duct 48 and delivery port 44 located towards an opposite end. Accordingly, fluid is capable of being delivered to the head central hub 35 and then to flow radially outward through ducts 36 (via the distributed disc 60) and into each shroud 40 to each respective nozzle 29, 33. Due to the angular arrangement of disc slots 63, a selection only of cutter units 13 are supplied with fluid at any one time as head 15 rotates in direction R₁. Accordingly, a selection of the first and second nozzles 29, 33 are active to produce respective fluid jets onto the selections 28 of buttons 19 and cutter hubs 25 that are being used at that specific time instance when cutting rock. In particular, the active cutter units 13 and accordingly first and second nozzles 29, 33 include only those cutter units 13 arranged over the same corresponding angular distance a relative to the distributor slots 63.

According to aspects of the present invention, machine 10 and/or each head 15 may further comprise a fluid flow interrupter configured to provide an intermittent flow of fluid to the nozzles 29, 33. Such an interrupter may be implemented as a specifically configured disc mounted at the central boss in place of, or in addition to, disc 60. The distributor disc 60 (and optionally the fluid flow interrupter disc) are beneficial to provide an efficient use of fluid to a selection only of the cutter units 13.

The above embodiment is described with reference to each of the discs 14 having cutting buttons 19. According to further embodiments, each disc 14 comprises a specifically configured radially outer perimeter edge region adapted to abrade rock (without the need for additional cutting buttons 19). According to such an embodiment, the first nozzles 29 are configured to direct a fluid jet to the cutting edge of each of the discs 14.

ROTARY CUTTING HEAD WITH FLUID SUPPLY DUCTING

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