The present invention relates to mineral breakers. BACKGROUND OF THE INVENTION Our mineral breaker was first disclosed in Australian Patent Specification No.

463819. Such a mineral breaker was revolutionary at the time since it embodied a system whereby a plurality of mineral beds are defined within a rotating element thus ensuring the majority of the wear (save for a hardened wear tip) is of mineral against mineral. Our New Zealand Patent Specification No. 201190 discloses an improvement whereby, as an enhancement, a hardened wear tip blade is mounted within a recess at the edge of a carrier which is to be positioned at a position where, in the manner of a weir, the smaller pieces of mineral overflow to exit the device.

US Patent Specification No. 4940188 of J Rodriguez and D Rodriguez discloses yet a further refinement of the system. US Patent No. 4,940,188 discloses the use of a weir member which acts substantially as a straight edged wear tip but which better manages the wear erosion.

The full content of the aforementioned patent specifications (including any equivalents thereof) are hereby here incorporated by way of reference.

The present invention relates to a method of providing an improved mineral breaker in that there is a prospect of enhanced tip life, components for attachment into a mineral breaker so as to define such tips, related means and methods which will, at least, provide an alternative to any disclosed in any of the aforementioned patent specifications and/or which may go some way to providing wear enhancement.

It is therefore an object of the present invention to provide means and/or methods relating to mineral breakers which will at least provide the public with a useful choice. The present invention recognises the benefit of shaping the retained bed of material to a trough-like form so that a greater volume of material being thrown from the bed of the rotor (after migration over the wear tip) moves along that material defined surface with some of the thrown material only being able to contact the wear tip. BRIEF SUMMARY OF THE INVENTION

Accordingly, in a first aspect the present invention consists in a tip defining component or assembly for inclusion in a rotor of a mineral breaker, said tip being engageable directly to or via a holder to the rotor to define a weir-like edge that extends

substantially transversely of the direction from which mineral pieces in use are to overflow from a retained bed thereof to exit a port of the rotor, said edge being characterised in that it is configured, assembled or otherwise arranged to provide at a region of flow enhancement such that a greater depth of mineral pieces passes over that edge region and to retain a bed of material having a transverse surface conforming to the weir-like edge.

Preferably, said edge is 'V, 'U' or otherwise scalloped in its configuration. Preferably, said edge is formed from a unitary member.

In other forms of the present invention, said 'V, 'U' or otherwise scalloped edge includes a replaceable wear region at the bottom of the 'V, 'U' or scallop.

Preferably, said tip component or assembly is provided with a holder, said holder having apertures or other means that facilitates the assemblage thereof into a rotor of a mineral crusher.

Preferably, the component, assembly, etc. is substantially as hereinafter described with or without reference to any of the accompanying drawings.

In a further aspect, the present invention consists in a mineral crusher of a kind having a rotor into which mineral to be crushed is fed substantially axially of the rotor direction to thence migrate via a weir-like member/assembly retained bed of mineral pieces to flow from the rotor via at least one circumferential or peripheral port, the apparatus being characterised in that said weir-like member/assembly of the apparatus (of which preferably there are a plurality, ideally three) is provided with a replaceable edge defining component or assemblage which provides a flow depth enhancing edge configuration.

In another aspect the invention is a mineral breaker of a kind having a rotor supported for rotation about a substantially vertical axis, wherein a tip defining component or assembly engaged to, or forming part of a holder itself engaged to, the rotor for each bed of retained material pieces defines a weir-like edge that extends substantially transversely of the direction from which the pieces of material are to overflow from the retamed bed thereof, the arrangement being to define a retained bed of a trough-like cross-sectional surface along which trough defined by the retained material the majority of the pieces of material to be thrown from the rotor passes. Preferably, said edge configuration is 'V, 'U' or otherwise scallop-like shaped. Preferably there exists a plurality of said weir-like members.

Preferably there exists three of said weir-like member/assembly. In yet a further aspect, the present invention consists in a method of minimising wear on a tip in a rotary mineral crusher of a kind previously exemplified wherein a significant quantity of the flow from the retained bed or beds is in a flow of increased depth over a wear tip (as herein defined or described) as a result of a preferred 'V, 'U' or other scallop-like edge thereof being defined that extends transversely of the flow direction from said retained bed(s) from the bed of retained material with the retained bed having a cross-sectional surface substantially conforming to the shape of said wear tip. In yet a further aspect the present invention consists in a method of minimising wear in a rotary mineral crusher having a rotor into which the mineral to be crushed is fed substantially axially of the rotor direction to thence migrate via weir-like member/assembly retained bed of mineral pieces to flow from the rotor via at least one circumferential or peripheral port, wherein a significant quantity of the flow from the retained bed or beds does not contact the surfaces parallel to the direction of flow, above and below said tip as a result of the preferred 'V, 'U' or other scallop-like wedge thereof being defined that extends transversely of the flow direction from said retained bed(s).

In a further aspect, the present invention consists in a method and/or apparatus suitable for retro-fitting rotaiy mineral breakers to provide the enhancements of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

Preferred forms of the present invention will now be described with reference to the accompanying drawings in which: Figures 1 to 7 are those of our New Zealand Patent Specification No. 201190, the prior art tip (preferably of tungsten carbide grade 438) 4 being held in a bed retaining configuration by a carrier blade 3 having apertures 5 and 6 to respectively receive mounting bolts and to receive threaded studs;

Figure 8 shows the feed direction (axially with respect to the rotor), the flow direction after movement onto a retained mineral bed and the circumferential or radial exiting from the rotor over a wear tip such as 4;

Figure 9 is Figure 12 taken from US Patent No. 4940188 showing another prior art embodiment showing therein a wear tip 27;

Figures 10 through 14 show a number of different embodiments of a tip configuration (in conjunction with a holder, blade or the equivalent) within the scope of the present invention;

Figure 15 through 19 show alternative embodiments of a tip configuration within the scope of the present invention;

Figure 20 illustrates a cut away view of a mineral breaker showing a tip configuration within the mineral breaker; and

Figure 21 illustrates a preferred configuration of a tip. DETAILED DESCRIPTION In accordance with the present invention, the wear of a tip (preferably of tungsten carbide) can be further enhanced by m-inimising the contact thereof with mineral pieces as they flow thereover in the manner of a weir. Such enhancement is best achieved by concentrating the flow from a condition as shown in Figure 8 (where the flow is substantially even over the substantially straight edge) to a condition where, should any of the edge configurations shown in Figures 10 through 14 be adopted, there is a minimum of flow over some outer regions of the tip (thus reducing wear thereover) but a greater depth of flow over a central region, (ie. the scalloped region) such that there is a reduced tendency for each piece of mineral to contact the wear tip, ie. there is an enhancement of the mineral to mineral contact as pieces move from the bed over the wear tip and hence a lower percentage of the mineral pieces contacting the tip.

The embodiment as shown in Figure 10 has an edge profile of the tip A in the form of a 'V which can be enhanced as to wear characteristics by the provision of an inset or insert (preferably also of tungsten carbide) B which is at the base of the 'V form.

Figure 11 is another variation where the scallop shape is more in the form of a channel having a flat bottom region C with inclined sides D. It is optional whether or not the members C and/or D can independently be changed or whether or not it is a fabricated or unitary structure.

Figure 12 is another variation on the theme of Figures 10 and 11 where there is a substantially 'U' shaped scallop in the tip E. Figure 13 is a form with upper regions F leading to a mineral retaining lower 'V defining region G through which many pieces in the bed will not easily pass thereby retaining a wall of mineral (perhaps to the level shown by the dotted line) which then acts in much the same way as, for example, tungsten carbide edge C in Figure 11.

Figure 14 is a fabricated edge form substantially of the configuration as shown in Figure 12.

Other variations within the scope of the present invention are also possible including those where the wear tips are mounted from separate holders or blades which

5 are to be mounted in juxta position or otherwise proximate one to the other so as to act in a manner substantially as described in the prior art or as is envisaged from the combined forms as shown in Figures 10 through 14.

Persons skilled in the art will appreciate how components in accordance with the present invention can be either the wear pieces themselves shown in Figures 10 through 10 14 or the assembly of the wear pieces and the holders therefor, the holders in Figures 10 through 14 being designated generally by the letter I and having, by way of example, a number of apertures therethrough to allow the mounting of the same in the prior art manner (as in Figure 8) within the rotor.

In preferred forms, where a 'V type edge is defined, preferably the ideal angle is 15 about 90°, ie. much more steeper forms will jam as in the lower regions in the embodiment of Figure 13 while much more open channel forms do not provide an optimal mineral piece contacting flow over the tungsten carbide with only a minimum of the mineral pieces contacting the wear surface. The shape of the edge also minimises the wear on the surfaces above and below the edge, the surfaces being part of the mineral 20 breaker.

Preferably the tip from edge to edge is of the order of 100mm long.

Persons skilled in the art will appreciate that tips in accordance with the present invention can be used to derive an advantage in prior art rotary mineral crushers as well as being incorporated in new crushers. 25 All forms of the present invention falling within the scope of any one of the aforementioned statements of invention or substantially as hereinbefore described are within the scope of the present invention.