US20060061206A1

US20060061206A1 - Tool, cutter and button disk

Info

Publication number: US20060061206A1
Application number: US11/206,823
Authority: US
Inventors: Peter Nava
Original assignee: Sandvik Intellectual Property AB
Current assignee: Sandvik Intellectual Property AB
Priority date: 2004-08-20
Filing date: 2005-08-19
Publication date: 2006-03-23
Also published as: SE525838C2; ZA200505598B; SE0402051D0; SE0402051L

Abstract

A tool for mining rock by means of undercutting includes an attachment part which defines a center longitudinal axis, and a holder mounted to the attachment part by bearings for rotation relative thereto about the axis. An outer surface of the holder includes a circumferentially extending first groove. A button disk is mounted on the cutter and includes an inner surface having a circumferentially extending second groove. One of the grooves is superimposed relative to the other groove to define therewith a space. A wire extends within the space to hold the button disk on the cutter.

Description

The present application claims priority under 35 U.S.C. §119 to Patent Application Serial No. 0402051-7 filed in Sweden on Aug. 20, 2004.

FIELD OF THE INVENTION

The present invention relates to a tool, a cutter and a button disk for mining of rock material by means of undercutting.
In WO-A1-03001031 a device is shown that breaks rock material with the assistance of a tool that uses undercutting to rationally break quantities of rock material without creating much dust. However, the known tool has shown to be expensive to use.

OBJECTS OF THE INVENTION

One object of the present invention is to provide a cutter and a button disk which give the same advantages as the prior art.
Another object of the present invention is to provide a cutter with good stability.
Still another object of the present invention is to provide a cutter with a good life-span.
Still another object of the present invention is to provide a cutter, which is inexpensive to use.
Still another object of the present invention is to provide an interchangeable button disk.
These and other objects have been achieved by means of a tool for mining rock preferably by means of undercutting. The tool comprises an attachment part which defines a center longitudinal axis, and a holder mounted to the attachment part by bearings for rotation relative thereto about the axis. An outer surface of the holder includes a circumferentially extending first groove. A button disk is mounted on the cutter and includes an inner surface having a circumferentially extending second groove. One of the grooves is superimposed relative to the other groove to define therewith a space. A wire extends within the space to hold the button disk on the cutter.
Another aspect of the invention relates to the cutter which defines an axis of rotation and comprises a holder, a button disk mounted to a front portion of the holder, and a wire oriented in a space defined by mutually superimposed circumferential grooves of the holder and the button disk, for securing the button disk to the holder.
Yet another aspect of the invention relates to a button disk adapted to be rotatably journaled on a holder and defining an axis of rotation. The button disk carries rock breaking elements at a front portion thereof and includes a circumferential groove adapted to receive a wire for attaching the button disk to the holder.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof in connection with the accompanying drawing in which like numerals designate like elements, and in which
FIG. 1 shows a cutter according to the present invention in a partly cross-sectional side view.
FIG. 2 shows an exploded view of a tool in a partly cross-sectional side view, including a cutter and a button disk according to the present invention.
FIG. 3 shows a button disk according to the present invention in cross-section according to line III-III in FIG. 2.

DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 2 shows a tool 10 for mining of rock material preferably by means of undercutting. The tool comprises an elongated attachment part 11 a cutter 12. The attachment part 11 has a substantially parallelepipedical cross-section and comprises essentially plane parallel lower and upper sides united by substantially plane parallel connector surfaces, i.e. a support surface and a free surface, and an end surface. The underside and the support surface form an internal second acute angle, which is from 70° to 85°.
A bearing journal 13 is formed integrated with the attachment part 11, whereby the cutter 12 is mounted on the journal 13 for rotation about a center axis CL. The cutter 12 comprises substantially three separate parts, i.e. a holder 40, a button disk 112 and a wire 24.
The cutter 12 has a number of rock breaking means, preferably in the form of hard metal buttons 14, arranged in an annular row at a distance from each other in the circumferential direction of the cutter 12. Said distance is at least double the diameter of the button 14. By the expression “hard metal” is here meant a metal carbide, such as tungsten carbide (TC) or similar, sintered together with a binder phase, such as cobalt (CO) or nickel (Ni). A number of bearing arrangements are provided between the cutter 12 and the journal 13. The cutter 12 is symmetrical and rotatable relative to the journal 13 about the rotational axis CL such as is more closely described in WO-A1-03001031.
The button disk 112 is preferably substantially symmetrically configured about a rotational axis CL and is stationary relative to a protrusion 113 of the journal 13. The cutter 12 has an external cylindrical surface 15 to receive radially directed forces. The cylindrical surface 15 is provided in connection with a first end of the cutter 12 which faces away from the attachment part 11. A shoulder or abutment surface 29 oriented perpendicular to the rotational axis CL is provided on the protrusion to receive axial forces. The shoulder 29 connects perpendicularly to the surface 15. The shoulder 29 is provided on a cylindrical base 36 connected to the attachment part 11. The base 36 transfers into the attachment part 11 via a stop surface 50. The stop surface 50 has a greater radial extension than the attachment part 11 and is perpendicular to the rotational axis CL. A circumferential groove 23A is provided in the surface 15. The groove 23A has a substantially semi-circular cross-section. The groove 23A is provided at a distance from the shoulder 29, which distance is shorter than 50% of the axial extension of the surface 15, preferably shorter than 40% of the axial extension of the surface 15.
The button disk 112 has substantially the shape of a circle. The button disk 112 comprises a substantially planar, open first end surface 31, which is perpendicular to the rotational axis CL and which connects to a substantially conical peripheral surface. The peripheral surface comprises holes which hold the buttons 14. The peripheral surface further connects to an axially rearward tapering outer surface 33, which by wiry minerals has a breaching function. The surface 33 may include wear protection in the shape of a hard weld or a number of hard metal buttons 14. The surface 33 further connects to a cylindrical jacket surface 32 of the button disk 112. Said jacket surface 32 can be arranged radially outside of an imaginary cylinder that the jacket surface of the cylindrical base 36 forms.
The button disk 112 comprises a substantially planar open second end surface or abutment surface 34, which is perpendicular to the rotational axis CL and connects to the cylindrical jacket surface 32.
The button disk comprises a central cylindrical hole 35 whose wall constitutes an internal cylindrical surface 16. A circumferential groove 23B is provided in the surface 16. The groove 23B has a substantially semi-circular cross-section. The groove 23B is provided at a distance from the second end surface 34, which distance is shorter than 50% of the axial extension of the surface 16, preferably shorter than 40% of the axial extension of the surface.
Buttons 14 of hard metal are fixed along a circumferential protrusion 30 on the button disk 112. The center line CL2 of each button forms an acute angle with the rotational axis CL of the cutter. The angle is from 60 to 80°, preferably about 75° An extension of the center line CL2 of each button intersects the rotational axis CL at a point X axially rearwardly of the groove 23B or the wire 24, see below. The term “rearwardly” here means that the extension line intersects the rotational axis CL on the attachment part 11 side of the groove 23B or the wire 24.
A hole 25 running tangentially from the groove 23B in the surface 16 (see FIG. 3) exits in the conical surface 33. The hole 25 is provided to enable insertion of a wire 24 of high-tensile steel; such as for example spring steel, into a space defined by superimposed grooves 23A, 23B. The wire 24 in the shown embodiment has a circular cross-section but can also have other cross-sections, such as a rectangular cross-section whereupon the grooves 23A, 23B would form a corresponding space. The wire has a cross-sectional area that is smaller than the cross-sectional area of the space formed by the grooves 23A, 23B to simplify insertion.
The tool 10 is mounted as follows. The attachment part 11 and the button disk 112 are aligned with the rotational axis CL, whereafter the button disk is pushed over the protrusion 113 such that the surfaces 15 and 16 slide against each other until the surfaces 34 and 29 abut against each other. Thereby, also the grooves 23A and 23B are aligned (mutually superimposed) such that an essentially circular cross-sectional space is created, as illustrated by FIG. 1. Thereby the wire 24 can be inserted through the hole 25 and into the formed space. Since the wire is elastically moldable the wire will follow the space until this it substantially fills the space. The wire 24 preferably has a length that at least corresponds to the length of the groove 23A. Preferably, the insertion of the wire is finalized with the aid of a narrow assister, which then is retracted when the wire has attained the desired position. The wire 24 will substantially prevent relative rotation of the protrusion 113 and the button disk 112 and is intended to secure the position of the button disk on the attachment such that the disc does not fall off of the attachment.
The hole 25 need not be sealed after the insertion of the wire 24. The surfaces 29 and 34 receive all reactional force from the rock being cut, while the principal task of the wire 24 is to retain the button disk 112 on the protrusion 113. The power that is required to shear the wire 24 must be so great that it in principle becomes impossible for this to happen, neither during work nor at disk change. Instead the button disk can be cut up into sections in for example two places. The hole 25 is used only for insertion of the wire. The surfaces 15 and 16 have substantially the same axial extension.
The tool 10 is intended to be mounted to a device in a machine, not shown, such that the stop surface 50 of the tool 10 may abut against a stop surface of the device. The attachment part 11 and the machine to be used with the tool 10 have been described in WO-A1-03001 031, which hereby is incorporated into the present description regarding the attachment part 11 and the machine. For example, by tilting the tool, a greater clearance is obtained for inactive parts of the tool, and a more favorable angle of attack for active buttons 14 is obtained. The tool is foremost intended for ore mining such as platinum ore, where the ore lies in narrow reefs in the rock. Frequently, three of the buttons 14 of the tool are active simultaneously, which gives a great surface pressure per hard metal button in relation to surface pressure at steel disks according to other prior art. This gives good penetration per button and requires smaller energy at the same time as the drill cuttings are not compressed in the formed groove but find accommodation between the buttons, which entails good life-span for the tool.
The present invention consequently relates to a tool, a cutter and a button disk that use undercutting to rationally break a great amount of rock material without creating much dust. The tool is simple, has good stability and a good lifespan. The tool is inexpensive to use since the button disk is interchangeable.
Although the present invention has been described in connection with a preferred embodiment thereof, it will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A tool for mining rock, comprising:

an attachment part defining a center longitudinal axis,

a holder mounted to a front portion of the attachment part by bearings for rotation relative thereto about the axis, an outer surface of the holder including a circumferentially extending first groove,

a button disc mounted on the holder and including an inner surface having a circumferentially extending second groove, wherein one of the grooves is superimposed relative to the other groove to define therewith a space; and

a wire extending within the space to hold the button disc on the cutter.

2. The tool according to claim 1 wherein the button disc includes hard metal buttons arranged in an annular row along an outer periphery of the button disc, a center line of each button disc intersecting the axis at a point located axially rearwardly of the wire.

3. The tool according to claim 1 wherein the button disc includes an internal surface overlying an external surface of the holder, the button disc including a rearwardly facing abutment surface abutting a forwardly facing abutment surface of the holder, each groove spaced by an axial distance from the abutment surfaces, the distance being shorter than 50% of an axial extension of the internal surface.

4. The tool according to claim 3 wherein the distance is shorter than 40% of the axial extension.

5. The tool according to claim 1, wherein the wire has a length substantially corresponding to a length of the space.

6. A cutter for mining rock material, the cutter defining an axis of rotation and comprising a holder, a button disk mounted to a front portion of the holder, and a wire oriented in a space defined by mutually superimposed circumferential grooves of the holder and the button disc, for securing the button disk to the holder.

7. The cutter according to claim 6, further including hard metal buttons arranged in a generally annular row along an outer periphery of the button disc; each button defining a center line which intersects the axis at a point located axially rearwardly of the wire, the button disc including an internal surface in which one of the grooves is formed.

8. The cutter according to claim 7 wherein the button disc includes a rearwardly facing abutment surface for abutting the holder, the groove of the button disc spaced forwardly from the abutment surface by a distance shorter than 50% of the axial length of the internal surface.

9. The cutter according to claim 8 wherein the distance is shorter than 40% of the axial length.

10. The cutter according to claim 6 wherein the button disc includes a central cylindrical hole defined by the internal surface.

11. A button disc adapted to be rotatably journaled on a holder and defining an axis of rotation; the button disc carrying rock breaking elements at a front portion thereof and including a circumferential groove adapted to receive a wire for attaching the button disc to the holder.

12. The button disc according to claim 11 wherein the button disc includes an internal surface in which the groove is formed.

13. The button disc according to claim 12 wherein the internal surface defines a central cylindrical hole passing through the button disc.

14. The button disc according to claim 13 further including a rearwardly facing abutment surface; the groove spaced forwardly from the abutment surface by a distance shorter than 50% of an axial length of the hole.

15. The button disc according to claim 14 wherein the distance is shorter than 40% of the axial length.