AU615230B2

AU615230B2 - Cutting tool for a mining machine

Info

Publication number: AU615230B2
Application number: AU24627/88A
Authority: AU
Inventors: Trevor John Martell; Christopher Nicholas Comyns Owers
Original assignee: De Beers Industrial Diamond Division Pty Ltd
Current assignee: De Beers Industrial Diamond Division Pty Ltd
Priority date: 1987-11-03
Filing date: 1988-11-02
Publication date: 1991-09-26
Anticipated expiration: 2008-11-02
Also published as: DE8813731U1; GB8825624D0; AU2462788A; GB2211875A; GB2211875B

Description

COMMONWEALTH OF AU 6

A

1 A 5 2 PATENTS ACT 1952-1962 COMPLETE SPECIFICATION (Original) FOR OFFICE USE Class Int. Class SApplication Number: Lodged: o Complete Specification Lodged: .0 Accepted: 0. Published: Priority: o0 a o Related Art: 0 0 Name of Applicant: DE BEERS INDUSTRIAL DIAMOND DIVISION (PROPRIETARY)

LIMITED

0 00 Address of Applicant: 45 MAIN STREET, JOHANNESBURG, TRANSVAAL, SOUTH

AFRICA

Actual Inventor(s): 1) CHRISTOPHER NICHOLAS COMYNS OWERS 2) TREVOR JOHN MARTELL Address for Service: DAVIES COLLISON, ONE LITTLE COLLINS STREET, MELBOURNE, 3000, AUSTRALIA Complete Specification for the invention entitled: "CUTTING TOOL FOR A MINING MACHINE" The following statement is a full description of this invention, including the best method of performing it known tox)o/us: :i ini~*ro--a~_ S: S SI 5 54* i S S S

E

BACKGROUND OF THE INVENTION This invention relates to a cutting tool for a mining machine of the type which is used to cut a variety of soft materials such as coal.

In mining machines of this type, a plurality of cutting tools (also known as picks) are positioned on a working surface, for example, the surface of a drum, and moved in a cutting direction against the face of the material to be cut. Each tool comprises a holding lug and a cutting element secured in a bore or socket in the lug. The cutting element may be made of a wear-resistant material such as cemented carbide. Alternatively, the cutting element may comprise an elongate pin, one end of which has secured to it an abrasive compact which provides a cutting edge for the element.

I- i SUMMARY OF THE INVENTION The invention provides a cutting tool for a mining machine of the type used to cut soft materials such as coal. The machine includes a holding lug one end of which is adapted to be mounted in or on a working surface of the machine.

The other end has an elongate socket having a longitudinal axis. A cutting element located in the socket comprises an elongate abrasive compact presenting major surfaces on each of opposite sides thereof, and a cutting point or edge at one end of the compact which extends beyond the elongate surfaces A mass of cemented carbide is bonded to each of the major surfaces and covers each surface completely, the total cemented carbide mass being at least 60 percent by e 15 mass of the cutting element. The cutting element is locatad in the socket such that the elongate abrasive compact lies in or parallel to the longitudinal axis of the socket.

The cutting element may take a variety of forms. For example, it may take the form of a pencil having a centre

I

S• core of cbrasive compact surrounded completely by a "o cemented carbide sleeve which is bonded to it. In another

V.

example, the compact has a rectangular section and presents elongate rectangular major surfaces on each of opposite sides thereof to which are bonded cemented carbide masses.

DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a partially sectional side view of an embodiment of the invention; Figure 2 is a plan view of Figure 1; Figure 3 illustrates a partially sectional side view of a second embodiment of the invention; Figure 4 is a plan view of Figure 3; Figure 5 illustrates a partially sectional side view of a third embodiment of the invention; 1- 4 Figure 6 illustrates a plan view of Figure 5; and Figure 7 is a partially sectional side view of a fourth embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION The abrasive compact may be any known in the art. Abrasive compacts consist essentially of a mass of abrasive particles present in an amount of at least 70 percent, preferably 80 to 90 percent, by volume of the compact bonded into a hard conglomerate. Compacts are polycrystalline masses containing a substantial amount of direct particle-to-particle bonding. The abrasive particles of the compacts are invariably ultra-hard abrasives such as diamond and cubic boron nitride. Diamond and cubic born nitride compacts are manufactured under conditions of temperature and pressure at which the abrasive particle is crystallographically stable.

The cutting elements which are used in the invention may be made by a method described in British Patent Specification No. 1,579,204.

j The total cemented carbide mass will typically be at least 60 percent by mass of the cutting element. The cemented carbide may be any known in the art, preferably cemented tungsten carbide.

Four embodiments of the invention will now be described with reference to the accompanying drawings. Referring first io Figures 1 and 2, a cutting tool for a mining machine comprises a holding lug 10 having one end 12 adapted to be mounted in or on the working surface of a rotatable drum, and a cutting end 14. The cutting end 14 has an elongate socket 16 in which is mounted a cutting element 18. The cutting element 18 comprises a cylindrical core 20 of abrasive compact surrounded by a 910715,GJNDAT.053,24627.res,4 sleeve of cemented carbide 22 which is bonded to it. The cutting element 18 is located in the socket such that the core 20 lies in or parallel to the longitudinal axis of the socket. The core 20 presents a cutting point 24. The cutting element is, in effect, of pencil-shape. The cutting element may be brazed into the lug which itself can rotate in the drum surface.

It will be seen in the drawings that core 20 presents major surfaces on each of any two opposite sides of the core, defined by the cylindrical exterior of the core, that cutting point 24 extends beyond these surfaces, and that carbide sleeve 22 covers each of the major surfaces completely.

ot The embodiment of Figures 3 and 4 is similar to that of Figures 1 and 2 and like numerals are used to describe like parts. The cutting element 26 in this embodiment is of sandwich-shape having an elongate abrasive compact core 28 of rectangular section which presents major surfaces 30, 32 on each of opposite sides and to which are bonded cemented carbide supports 34. Core 28 is parallel to the longitudinal axis of the socket 16. Carbide supports 34 cover the respective surfaces 30, 32 completely. The abrasive compact 28 is shaped to present a cutting edge 36 which extends beyond surfaces 30, 32. The cutting edge 36 may also be a point, as in Figure i. The cutting element is brazed to the lug. The cutting tool of this embodiment will be non-rotating in use.

The embodiment of Figures 5 and 6 is again similar to that of the previous embodiments. Like numerals are used to designate like parts. In this embodiment, the cutting element 38 comprises an elongate abrasive compact 40 of rectangular section presenting major surfaces 42, 44 to which are bonded cemented carbide supports 46. The abrasive compact presents a cutting edge 48. The cutting 910715,GJNDAT.053,246Z7.res,5 6 element is located in and bonded to a supporting body which itself is fixed to the cutting end 14 of the holding lug. The cutting tool of this embodiment will be nonrotating in use.

The embodiment of Figure 7 is similar to that of Figures 1 and 2 and like numerals represent like parts. It will be noted that the side surface 20a of the sleeve 22 of the cutting element 18 tapers inwardly. Further, the sides 14a of the cutting end 14 of the holding lug are cut-away, minimising erosion and abrasion of this end during use.

i ,e 0 r u e l 910715,GJNDAT.053,24627.res,6

Claims

1. A cutting tool for a mining machine of the type used to cut soft materials such as coal comprising: a holding lug one end of which is adapted to be mounted in or on a working surface of the machine and the other end has an elongate socket having a longitudinal axis and a cutting element located in the socket, the cutting element comprising an elongate abrasive compact presenting major surfaces on each of opposite sides thereof, and a cutting point or edge at one end of the compact which extends beyond the elongate surfaces; a mass of cemented carbide bonded to each of the major surfaces and covering each surface completely, the total cemented carbide mass being at least 60 percent by mass of the cutting element; and the cutting element being located in the socket such that the elongate abrasive compact lies in or parallel to the longitudinal axis of the socket.

2. A cutting tool according to claim 1 wherein the cutting element has the form of a pencil in which said abrasive compact comprises a core completely surrounded by S: a cemented carbide sleeve which forms said mass and is bonded to the compact.

3. A cutting tool according to claim 1 wherein the abrasive compact of the cutting element has a rectangular section and presents elongate rectangular major surfaces on each of opposite sides thereof, to each of which is bonded said cemented carbide mass.

4. A cutting tool according to claim 1 and substantially as herein described with reference to any one of Figures 1 to 7 of the accompanying drawings. DATED this 15TH day of JULY 1991 DE BEERS INDUSTRIAL DIAMOND DIVISION (PROPRIETARY) LIMITED By its Patent Attorneys DAVIES COLLISON S 1 910715,GJNDAT.053,24627.res,7