GB2195682A

GB2195682A - Mineral cutting means

Info

Publication number: GB2195682A
Application number: GB08721914A
Authority: GB
Inventors: Derek John Bunting; Alexander Brian Graham
Original assignee: WIMET MINING Ltd
Current assignee: WIMET MINING Ltd
Priority date: 1986-09-19
Filing date: 1987-09-17
Publication date: 1988-04-13
Also published as: ZA876884B; GB8622605D0; DE3731381A1; GB8721914D0; AU7834987A

Description

GB2195682A 1 SPECIFICATION front views of a mineral cutting tool according

to the invention mounted on a carrier drum, Mineral cutting means and Fig. 3 is a transverse sectional view of the This invention relates to mineral cutting tools 70 same tool on its carrier drum.

and to mineral cutter assemblies which carry The drawing illustrates only fragmentarily a one or more cutting tools. tool carrier which is in the form of a rotary The demands of most mineral cutting oper- drum (not shown) having at least one helical ations require the use of tools that can be rib 2 on its periphery, a series of cutting tools easily and quickly replaced. Conventional cut- 75 4, only one of which is shown, being ting tools therefore comprise a cutting tip mounted at intervals along the or each rib to mounted on a shank which is releasably inproject radially from the drum. Cutting tips 6 serted in an aperture of a mounting. Because on the tools are advanced in the direction of the cutting tip must project a substantial dis- the arrow A with the rotation of the drum.

tance from the mounting, the shank is rela- 80 Such drum cutters are known for coal cutting, tively large and continuing increases in the for example.

maximum size of cutting machines has led to At the tool locations, the rib 2 is cut away the need for incieasingly massive cutting to provide undercut recesses 8 into which tools. Such tools are used for breaking or ex- mounting blocks 10 can be slid laterally and cavating and in mining and road surface re- 85 permanently secured, e.g. by welding. Each moving operations. tool mounting further includes a peg 12 fixed According to one aspect of the present in- in the block 10, but it is of course possible to vention, there is provided a mineral cutting form the mounting as a unitary member, tool having an elongate shank in the rear end whether as a combined peg and block or by of which is a longitudinally extending aperture 90 fixing the peg directly to the drum rib 2. Be to receive a mounting member for holding the cause the mounting peg is a separate part tool, said aperture tapering away from its rear secured to the carrier drum, it is possible to entry face, the aperture or another longitudimake it of a high carbon steel or like hardena nally extending surface of the tool being non- ble alloy without affecting the weldability of circularly formed with reference to a central 95 the main structure of the cutter drum. The longitudinal axis of the aperture to provide a peg can be permanently or releasably secured locating engagement that retains the tool non- in place.

rotatably relative to the mounting, and locking Each cutting tool has a shank with a front means being provided for retaining the tool or outer portion 14 of narrow cross-section, longitudinally on its mounting. 100 the larger axis of symmetry liesin a radial Preferably, the aperture has a non-circular plane of the drum. The rear or inner portion cross section, in particular an elongate cross 16 of the shank has an increased width to section with its major axis extending substan- accommodate an aperture 18 in which a pro tially in the cutting direction of the tool. jecting tapered portion 20 of the mounting According to another aspect of the inven- 105 peg sits.

tion, there is provided a mineral cutter as- The projecting portion of the peg and the sembly comprising a carrier member having at aperture 18 have corresponding generally ellip least one mounting on which a respective cut- tical tapered cross- sections so that the tool ting tool is held, the or each said tool having cannot rotate on its mounting. A locking de an elongate shank in the rear end of which is 110 vice is provided to fix the tool radially, that is an aperture extending longitudinally of the to say, longitudinally of the shank, this com shank, the carrier member being provided with prising a steel pin 22 held in the tool to be a corresponding outwardly projecting mounting urged into the aperture 18 by a resilient back member for the or each said tool, the or each ing block 24, the pin thus being forced into a mounting member and its associated tool 115 recess 26 in the peg. A bifurcated lug 28 is aperture having complementary tapering forms, provided at the rear of the tool shank for said aperture or another longitudinally extend- leverage when the tool is to be removed from ing surface of the top[ being non-circularly the mounting peg against the holding force of formed with reference to a central longitudinal the locking device.

axis of the aperture and being engaged by a 120 The portion 20 of the mounting peg and the surface of said mounting or a part rigid thereaperture can be given other non-circular cross with to retain the tool against rotation on the sections to hold the tool against rotation, but mounting, and locking means being provided in general it will be preferred to employ an to retain the tool longitudinally on the mount- elongate cross-section with its major axis at ing. 125 least approximate to the cutting direction of An embodiment of the invention will be de- the tool, as can best be seen in Fig. 3 of the scribed in more detail by way of example with illustrated example where the minor axis is reference to the accompanying drawings, in parallel to the rotational axis of the drum and which: the major axis therefore lies obliquely to the Figs. 1 and 2 are partly sectioned side and 130 rib. Polygonal, e.g. rectangular and diamond 2 GB2195682A 2 form, cross-sections are further examples, as aperture has non-circular cross-section.

well as circular modified by one or more flats. 3. A tool according to claim 2 wherein the It is also possible to provide a circular crossaperture has an elongated cross-section with section and to obtain angular location by co- its major axis extending substantially in the operating flats on an outer face of the tool 70 cutting direction of the tool.

shank and the opposed face of the drum 4. A tool according to claim 3 wherein said mounting, or internally by means of a key and cross-section is generally elliptical.

keyway. The use of a continuously curved 5. A tool according to any one of the pre- cross-section such as an ellipse is preferred, ceding claims wherein the shank has an elon however, because of the relative ease with 75 gate foremost cutting portion of a substan which both the internal and external surfaces tially lesser width than a rear shank portion can be machined to give a taper fit which will containing said mounting aperture.

hold the tool rigidly on the mounting peg. 6. A mineral cutter assembly comprising a In the preferred arrangement shown, the ex- carrier member having at least one mounting ternal cross-section of the apertured rear por- 80 on which a respective cutting tool is held, the tion 16 of the shank is kept substantially or each said tool having an elongate shank in within the thicknss of the helical rib 2 of the the rear end of which is an aperture extending cutter drum and this wider part of the shank longitudinally of the shank, the carrier member also projects very little beyond the rib radially. being provided with a corresponding out The locking device 22, 24 and the release lug 85 wardly projecting mounting member for the or 26 are also within the rib height and are con- each said tool, the or each mounting member veniently disposed in a part of the shank and its associated tool aperture having com through which the major axis of the aperture plementary tapering forms, said aperture or cross-section extends. another longitudinally extending surface of the The front portion of the shank projecting 90 tool being non-circularly formed with reference from the rib and carrying the cutting tip 6 to a central longitudinal axis of the aperture therefore -has a relatively small frontal area but and being engaged by a surface of said its depth in the cutting direction is similar to mounting or a part rigid therewith to retain the the depth of the rear portion 16, so that the tool against rotation on the mounting, and required strength and stiffness is obtained 95 locking means being provided to retain the with economy of material. By mounting the tool longitudinally on the mounting.

tool through an aperture in its shank and re- 7. An assembly according to claim 6, ducing the width of the shank beyond the wherein said complementary tapering forms of mounting aperture, the mass of the tool is the or each mounting member and tool aper further reduced as compared with a conven- 100 ture have an elongated cross-section with its tional tool that is mounted by insertion of the major axis extending substantially in the cut rear end of its shank into a carrier aperture. ting direction of the tool, These measures are particularly significant 8. An assembly according to claim 7 and with large size tools which are cumbersome said cross- section is generally elliptical.

and the frequent replacement of which be- 105 ' 9. An assembly according to any one of the comes increasingly inconvenient with their claims 6 to 8, wherein said at least one size. mounting is recessed into an adjacent region Although described in relation to a drum of the carrier member, the associated tool cutter for coal mining, it will be understood having a wider rear shank portion which con that the invention relates to mineral cutting 110 tains said mounting aperture and which termi generally and can be applied to different forms nates substantially within said carrier member of cutting machinery, including cutter heads, adjacent region, a foremost cutting portion of shearer drums, road planing drums and the shank projecting outwardly from said adja ploughing machines. cent region having a substantially lesser width 115 than said rear shank portion.

Claims

CLAIMS 10. An assembly according to claim 9

1. A mineral cutting tool' having elongate wherein the external crosssection of the rear shank in the rear end of which is a longitudi- shank portion of said at least one tool is lo nally extending aperture to receive a mounting cated substantially within the thickness of the member for holding the tool,, said aperture ta- 120 adjacent region of the carrier.

pering away from its rear entry face, the aper- 11. A mineral cutting tool constructed and ture or another longitudinally extending surface arranged for use substantially as described of the tool being non-circularly formed with herein with reference to the accompanying reference to a central longitudinal axis of the drawings.

'aperture to provide a locating engagement that 125 12. A mineral cutter assembly constructed retains the tool non-rotatably relative to the and arranged for use substantially as de mounting,-and locking means being provided scribed herein with reference to the accom for retaining the tool longitudinally on its panying drawings.

mounting.

2. A tool according to claim 1 when the I GB2195682A 3 Published 1988 atThe Patent Office, State House, 66/71 High Holborn, London WC 1 R 4TP. Further copies may be obtained from The Patent Office, Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD.

Printed by Burgess & Son (Abingdon) Ltd. Con. 1/87.