CUTTING APPARATUS

Abstract

A cutter head for excavating hard rock materials in rock face includes a carrier attachable to a cutter arm of a cutter machine and a drive shaft rotatably supported by the carrier. The drive shaft is rotatable about a drive axis and has at one end a support portion for mounting disc cutters. A plurality of disc cutters are mounted on the support portion and configured to perform undercutting against the rock face. Each disc cutter is rotatable about a respective support axis, the respective rotational axis of each disc cutter being configured to be substantially transverse to the rotational axis of the cutter head. A mining machine including the cutter head is also disclosed.

Claims

1. A cutter head arranged for excavating hard rock materials in rock face, the cutter head comprising: a carrier attached to a cutter arm of a cutter machine, and a drive shaft rotatably supported by the carrier, the drive shaft being rotatable about a drive axis and including at one end a support portion for mounting disc cutters; and a plurality of disc cutters mounted on the support portion and configured to perform undercutting against the rock face, each disc cutter being rotatable about a respective support axis, wherein the disc cutters are attached on the support portion in a manner such that the support axes of the disc cutters extend to intersect with one another at the drive axis at an intersection point and lie within a common conical surface.

2. The cutter head according to claim 1, wherein the plurality of disc cutters are spaced apart from the intersection point by a same offset.

3. The cutter head according to claim 1, wherein the plurality of disc cutters have a same configuration in structure, the plurality of disc cutters being uniformly distributed about a circumference in a plane perpendicular to the drive axis.

4. The cutter head according to claim 1, further comprising a flywheel coupled to the drive shaft.

5. The cutter head according to claim 1, wherein each disc cutter includes a single layer of an annular cutting edge, or a single layer of an annular cutting arrangement defined by cutting tips of a plurality of cutting elements arranged on an outer periphery of the disc cutter.

6. The cutter head according to claim 1, wherein the support axis of each disc cutter extends inclined relative to the drive axis by a disc inclination angle, the disc inclination angle being in a range between 60 to 80 degrees.

7. The cutter head according to claim 1, wherein each disc cutter is independently rotatable about the respective support axis via a bearing.

8. The cutter head according to claim 1, further comprising a motor supported on the carrier, the motor being configured to actuate the drive shaft to rotate about the drive axis via a gear mechanism, the gear mechanism including a first stage planetary gear coupled in series to a second stage planetary gear.

9. The cutter head according to claim 1, further comprising a plurality of material cleaning parts deposited between neighbouring disc cutters, the plurality of material cleaning parts being configured to clean material from the rock face.

10. The cutter head according to claim 1, wherein a gap between two neighbouring disc cutters is minimised so that the cutter head includes as many disc cutters as possible, the disc cutters having a diameter of 13 inches.

11. A cutter apparatus for creating a tunnel, the cutter apparatus comprising: a main frame; a support mounted on the main frame and slidable relative to the main frame in the longitudinal direction of the cutter apparatus; a cutter arm mounted on the support and rotatable about a vertical axis; and a cutter head according to 1 mounted at a distal end of the cutter arm.

12. The cutter apparatus according to claim 11, wherein the cutter head is mounted at a distal end of the cutter arm in a manner that a free-cutting angle is defined by the rock face and a plane formed by the cutting edge of the disc cutter in cutting is in a range of 5 to 40 degrees.

13. The cutter apparatus according to claim 11, further comprising a loading means mounted on a lateral side of the cutter head, the loading means being configured to collect material that is cut off by the cutter head.

14. The cutter apparatus according to claim 11, further comprising a slewing gear mechanism or a linear arm actuator arranged to actuate the cutter arm to slew about the vertical axis, and/or a support actuator to actuate the support to slide relative to the main frame.

15. The cutter apparatus according to claim 11, further comprising a plurality of floor and roof engaging means mounted at the main frame and/or at the support, the plurality of floor and roof engaging means being extendible and retractable to raise and lower the cutter apparatus.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0032] 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:

[0033] FIG. 1A is a top view of a cutter head according to a specific implementation of the present invention, with the front part in sectional view;

[0034] FIG. 1B is a front view of the cutter head of FIG. 1;

[0035] FIG. 1C is a schematic representation of a speed reduction mechanism of cutter head of FIG. 1;

[0036] FIG. 2 is a plan view of a cutter apparatus according to a specific implementation of the present invention;

[0037] FIG. 3 is a magnified top perspective view of a part of a cutter head according to a specific implementation of the present invention;

[0038] FIG. 4 is a front perspective view of a cutter apparatus according to another specific implementation of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

[0039] FIG. 1A illustrates a cutter head 100 with the front part in sectional view, the front side of which is indicated by arrow 122, the cutter head 100 comprises a cylindrical shaped or drum-like body that may be fastened to a suitable holding arm or boom 203, the body includes a housing or stationary holder 101 which may be tubular form having a chamber as a receptacle for shaft and gear, and a drive shaft 102 that is journaled to the housing 101 freely rotatably by means of bearings 120 such as tapered roller bearings arranged in an O arrangement or X arrangement, an electronic or hydraulic motor 106 can be mounted on the body for actuating the drive shaft 102 to rotate about a drive axis 103 via a speed reduction mechanism, motor 106 is connected to motor shaft 121 that is supported via bearings 120 on housing 101. As shown in FIG. 1C, the speed reduction mechanism includes a bevel gear stage 114 in engagement with a first stage planetary gear 117 which is in series coupled to a second stage planetary gear 118, the carrier of the first stage planetary gear introduces rotation to the sun gear of the second stage planetary gear 118, a bevel gearwheel 116 may be shrink-fit connected to a gear shaft 119, gear shaft 119 is supported via bearings 120 on housing 101, at rear side the gear shaft 119 it is coupled to a flywheel 115, the front side of the gear shaft 119 acts as input to the sun gear of the first stage planetary gear 117. The rotation of bevel gear stage 114 is introduced by motor 106 and consequently transferred to shaft 119, finally the carrier of the second stage planetary gear introduces rotation to the drive shaft 102. The gear ratio for the bevel gear stage 114, the first stage planetary gear 117 and the second stage planetary gear 118 may be set depending on the properties of motor 106 and a target rotational speed of the cutter head, and may be chosen such that the speed of the drive shaft 102 is in the range of 20-60 rpm.

[0040] Turn back to FIG. 1A, the drive shaft 102 projects out of a front end of the housing 101 and includes therein a cutter wheel 109 for mounting a group of disc cutters 104, the cutter wheel 109 and the drive shaft 102 are connected fixedly in terms of rotation to one another or integrally formed in one piece. The group of disc cutters 104 are of the same kind of disk roller cutters and have the same design details, i.e. the same in dimension, in structure and in drive mechanism, in other words, they are structurally and functionally identical to each other. The arrangement of all disc cutters 104 disclosed herein may have a symmetrical or substantial symmetrical configuration with respect to the drive axis 103. Referring to FIG. 1B the disc cutter 104 are mounted in a generally radial direction on the cutter wheel 109 facing outward, uniformly spaced apart from each other on a same outer circumference 140.

[0041] Each disc cutter 104 is freely rotatable about a support axis 105, the support axis 105 may intersect with one another at the drive axis 103 at intersection point 108. The support axis 105 of each disc cutter runs inclined relative to the drive axis 103 by a disc inclination angle 107 which shall be substantially the same value for all disc cutters. Thus the respective support axes 105 define a conical surface with apex at the intersection point 108. The disc inclination angle 107 is dependent on the diameter of the disc cutters and the separation 130 between a centre of cutter ring 112 and the drive axis 103, preferably the disc inclination angle 107 is in a range between 60 to 80 degrees, more preferably the angle 107 is 70 degrees.

[0042] Further, the disc cutters 104 are spaced apart from the drum axis 103 by the same offset 130 in radial direction and positioned in the same altitude along the direction of drive axis 103.

[0043] Each disc cutter may include a cutter disc or cutter ring 112 that is rigidly connected on one side to a cutter hub 111 that is in turn rotatably mounted at a disc shaft 124, bearings 125 permit the cutter hub to be freely rotatable around the disc shaft 124, a radially outer portion of each disc 112 by rotation of the disc configured to abrade rock and create a cut groove therein, each disc shaft 124 is of cylindrical shape and in rigid connection to the cutter wheel 109 e.g. via fastening screws.

[0044] Design details of a disc cutter 104 is partly shown in FIG. 3, annular cutter ring 112 is mounted on the cutter hub 111 via shrink-fit or form-fit or screw bolt connection. A plurality of cutter buttons 301 made of diamond or carbide or other hard material are consecutively and uniformly embedded along the outer periphery of the cutter ring, the buttons are oriented to face obliquely outwards with the tips forming a general annular cutter edge. A radial outer face with respect to the support axis 105 is indicated by reference symbol 126, the outer face is spaced apart from the intersection point 108 by an offset which is the same value for all disc cutters 104.

[0045] The cutter head 100 further includes a set of shovels 302 mounted fixedly in terms of rotation to the cutter wheel 109, each shovel extends in a respective plane across the drive axis 103, and is positioned between a pair of neighbouring disc cutter 104, by means of the shovel, released material can be loaded into a conveyor (not shown). For example the shovel can be a planar board suitable for scraping off rock deposits left on rock face.

[0046] FIGS. 1A to 1C are for illustrating purpose, in another embodiment, depending on the amount of disc cutters 104, support axis 105 of a disc cutter and that of an opposite disc cutter may not necessarily be in the same plane.

[0047] FIG. 2 illustrates one embodiment of a mining machine 200 for excavating hard rock, the machine comprises a main frame (chassis) 201 which is coupled to a pair of crawlers (or track wheels), the crawlers are driven via track gear to move the main frame within a tunnel, a support 202 is movably coupled to the main frame 201 and is actuated by linear drive 207 such as a hydraulic actuator to slide on the main frame 201 via a guide (not shown). The support 202 carries a pivoting mechanism 209 that is rotatable about a vertical axis 204, the pivoting mechanism 209 in turn mounts an arm structure 203 which can be cranked or bent, the arm structure 203 at its distal end carries a cutter head 100, optionally via a holder, a pair of actuators 206 such as hydraulic cylinders are coupled to the support 202 to rotate the pivoting mechanism 209 in horizontal plane, such that the cutter head 100 can be slew about an angle in range 0 to 180 degrees from initial position indicated as A (where the drive axis 103 runs substantially parallel to the longitudinal direction of the machine), to a position B.

[0048] The machine frame can be braced between the tunnel roof and floor by a plurality of jacking legs 208, wherein the jacking legs are arranged on both sides of the longitudinal centre plane of the machine frame.

[0049] From FIG. 2 it is seen that, when the drive axis 103 of the cutter head is parallel to the longitudinal direction of the machine, the enveloping of the disc cutters is located in the front 122 relative to the rotational centre 204, i.e. an angular offset 210 of outermost cutting edge of disc cutter is present, the angular offset 210 is defined by two rays starting from a rotation centre at the vertical axis 204, with one ray 212 towards outermost cutting edge, and the other ray 211 perpendicular to the drive axis 103 of the cutter head. The angular offset 210 may be set in the range of 0 to 25 degrees.

[0050] It is important to maintain a free-cutting angle (or called a contacting angle) of a disc cutter at an optimal value, FIG. 3 illustrates a cutter head in cutting operation, the free-cutting angle 303 is defined by the tangent line of the rock face at contacting point to rock and a plane of outer face 126, the plane of outer face 126 is formed by the annular cutting edge of the disc cutter. The free-cutting angle is preferably kept as a small value, it may be set in the range of 5 to 40 degrees, preferably, the free-cutting angle is in the range of 20 to 35 degrees.

[0051] During operation of a cutter head 100, an individual disc cutter 104 is subjected to two rotational movements about two different rotational axes, i.e. in a first rotational movements about the drive axis 103, and in a second rotation about support axis 105. In addition, the disc cutter 104 is subjected to a pivoting movements about vertical axis 204. The disc cutter 104 pierces into mining material, thereby causing cracks in the mining material and eventually creates an undercut or slot. A previous cutting path is indicated by reference symbol 306, a succeeding path to be cut is indicated by reference symbol 307, all shown in a horizontal plane. A disk cutter first cuts in the base rock along cutting path 307 to remove a free section 308, a succeeding disk roller cutter comes to crush the base rock to remove a free section 309. A maximal penetration 304 or undercut depth into the mining material, which is in radial direction with respect to the support axis 105, may be set, for example, in a range between about 2 mm and about 20 mm for hard rock mining material. A cut spacing 305, which is in radial direction with respect to the drive axis 103, lies in a range of 0 to 150 mm preferably between 5 mm and 70 mm.

[0052] During cutting, the pivoting speed of the cutter arm is controlled in such a way that, the cutter ring of a succeeding disc cutter 104 comes into contact with the material to be removed at a point which is offset in a common horizontal plane from that of the cutter ring of the preceding disc cutter, wherein the offset corresponds to a required penetration 304.

[0053] FIG. 4 illustrates another embodiment of a mining machine for excavating hard rock, the machine comprises a main frame 401, a support 402 movably coupled to the main frame 401 via a drawer structure e.g. a rod within a sleeve, and is actuated by an actuator 407 to slide on the main frame 401, a pivoting mechanism 409 carrying a cantilever arm 403 is mounted to the support 402, a cutter head 100 is mounted at the distal end of the cantilever arm. In this design, the longitudinal axis of cantilever arm 403 is substantially perpendicular to the drive axis of the cutter head.

[0054] The pivoting mechanism 409 includes a rotary drive or slew drive train inside, in order to achieve a specific reduction ratio, the drive train may comprise a first stage planetary drive coupled in series to a second stage planetary drive (not shown). A motor 411 is provided as resource to the drive train. Jacking legs 408 are connected the main frame. Additional jacking legs 410 may be provided to support the pivoting mechanism 409, optionally the additional jacking legs 410 may have rollers on foot. Other settings of the machine are similar to the machine of FIG. 2.

[0055] In operation, the machine 200 is set in the required position in the tunnel, depending on needs, operating parameters such as the slewing speed of the cutter arm, rotational speed of the cutter head etc. may be set. Jacking legs 208 are actuated to stabilize the machine within the tunnel; then cutter heads 100 is rotated via the motor 106, and cutter arm 203 is actuated to pivot about axis 204 to guide the cutter head to cut from position A to position B, thereafter cutter arm 203 is brought back to position A by pivoting of the arm in reverse direction. The support 202 together with the pivoting mechanism 209 is driven to slide forward by a distance corresponding to required sump depth, cutting is repeatedly performed from position A.

[0056] The sliding movement of support 202 and the succeeding cutting can be repeated many times until the maximal forward travel of the support 202 is achieved, then jacking legs 208 are retracted to engage the crawler 406 onto the ground. The machine 200 may then be advanced forward via crawler 406. Jacking legs are extended again for repeating the cutting cycle.

[0057] The slewing speed of the cutter arm is set dependent on the rotation speed of cutter head (amounts to 60 rev/min), the amount of disc cutters (8 to 12 pieces), and required penetration (2 to 20 mm).