AU2023285077A1

AU2023285077A1 - Improvements in stone crushing equipment

Info

Publication number: AU2023285077A1
Application number: AU2023285077A
Authority: AU
Inventors: Richard Sutherland
Original assignee: Sutherland Richard Keith
Current assignee: Sutherland Richard Keith
Priority date: 2022-12-21
Filing date: 2023-12-18
Publication date: 2024-07-11
Also published as: ZA202311562B

Abstract

A wear cap for use in combination with a top feed crusher, said wear cap providing an impact resistant and abrasion resistant impact surface which is uppermost in use and 5 being adapted to be removably securable over the apex of a crusher distribution plate or a crusher cone, by means of securing means positioned on the underside of the wear cap, being that side of the wear cap which in use lies adjacent to the apex of the crusher distribution plate or crusher cone; said wear cap being sized so that the periphery of the wear cap extends beyond the apex of the crusher cone or distribution plate. 10 Fig. 4 9 4/8 42 40 41 43 20 15 FIG 4

Description

4/8

42 41

43 20

15 FIG 4

IMPROVEMENTS IN STONE CRUSHING EQUIPMENT

Technical Field The present invention relates to improvements in stone crushing equipment, and in particular to stone crushing equipment of the type where stone to be crushed is fed from above onto a rotating and/or oscillating distributor plate or cone. In the specification, crushing equipment of this type is referred to as a "top feed crusher".

Background Art A stone crusher is used to reduce large rocks to small rocks, gravel, sand or rock dust. One step in the process is to reduce large rocks to smaller rocks, and there are a number of common types of crusher well known for this purpose: for example, a range of rotary crushers sold under the registered trademark BARMAC, gyratory crushers, jaw crushers, and cone crushers. The improvement of the present invention is particularly applicable to BARMAC crushers and cone crushers, but is also applicable to any of a range of top feed crushers.

A part cutaway view of a typical Barmac crusher is shown diagrammatically in Figure 1 of the accompanying drawings.

Figure 2 shows a cutaway view of the inner part of the crusher of Figure 1.

Referring to Figures 1 and 2, a crusher 10 has an outer housing 11 with an open port 12 at the top and an exit port 13 at the bottom. Over the central portion of the housing 11, the wall is lined by a series of spaced plates 14 which in use form pockets in which rocks being processed tend to lodge, to form reservoirs of rock as hereinafter described.

Along the longitudinal axis of the housing 11 a rotatable spindle 15 is mounted, which is rotated by drive belts from motors, none of which are shown. The upper end of the spindle 15 carries a rotor 16 which consists of upper and lower wear plates, 17, 18 secured to, and spaced apart by a series of spaced cavity wear plates 19 which are rigidly secured between the upper and lower wear plates 17, 18. In the centre of the rotor 16 is a distributor plate 20 (Figure 2) which is frusto conical in shape and which is secured on the upper end of the spindle 15 by means of a securing bolt (not visible) which is accessed through the centre hole 21 of the distributor plate 20.

In use, the rotatable spindle 15 and the rotor 16 are driven as described above; rocks to be crushed are poured through the port 12 and fall downwards through the crusher as indicated by arrows A, guided by a spreader 22 and by guide plates 22a. Some of the rocks fall in the direction of arrows B out towards the wall of the housing 11, where the rocks tend to lodge between the plates 14. The remainder of the incoming rocks move in the direction of arrows C through a feed tube (not shown) mounted in a central aperture 23 in the top of the upper wear plate and onto the surface of the distributor plate 20.

The rotation of the rotor 16 flings the incoming rocks falling onto the distributor plate 20 outwards through the gaps between the wear plates 19 (arrows D), and these rocks impact on the rocks lodged between the plates 14. Thus, the rocks are crushed predominantly by rock-on-rock contact, which tends to give a better particle shape and also reduces the wear on the metal components of the crusher. The crushed rock leaves the crusher through the exit port 13 (arrows E).

A major portion of the incoming rocks impact on the distribution plate 20, and this causes rapid heavy wear of the distribution plate, which normally has to be replaced frequently. For normal use, it would be expected that the distribution plate is replaced approximately once a week. This is a comparatively lengthy job, typically taking several hours. A further complication is that the screws securing the distribution plate to the top of the spindle may also be worn down by the impact of the rocks, and thus be very difficult to undo:- it may even be necessary to weld an extension onto the securing screw in order to be able to release it from the top of the rotor.

Distribution plates are heavy duty precision components therefore are comparatively expensive, and obviously the crusher cannot be used for several hours while the distribution plate is dismantled and replaced; this downtime also is expensive.

A typical cone crusher is shown diagrammatically in longitudinal section in Figure 3.

A cone crusher 30 provides a cone which is mounted on a main shaft 32 for eccentric rotation, and which supports a conical mantle 31 formed with a domed feed plate 31A. The mantle and feed plate rotate with the cone. The eccentric rotation of the cone means that the distance D between the upper surface of the mantle 31 and the adjacent surfaces of a stationary liner 33 varies as the cone rotates, thus varying the size of the particles which are crushed between the mantle and the liner, and which then fall through the exit port of the crusher, in the direction of arrow G.

Rock to be crushed is poured into the crusher in the direction of arrows F and impacts on the upper surface of the feed plate 31A. This tends to cause rapid wear on the upper surface of the feed plate, which necessitates a frequent replacement of the feed plate.

In another embodiment of a cone crusher, the cone is mounted on a shaft which is rotated about a vertical axis, rather than being rotated about an inclined axis, but the variation in the distance D is achieved by mounting the cone asymmetrically on the main shaft. The effect is the same as with the version shown in Figure 3:- the distance D between the upper surface of the mantel and the adjacent surfaces of a stationary liner varies as the cone is rotated.

Disclosure of Invention An object of the present invention is the provision of a wear cap which can be used in any of a range of top feed crushers as defined above, to extend the life of the replaceable crusher cones or distribution plates.

The present invention provides a wear cap for use in combination with a top feed crusher, said wear cap providing an impact resistant and abrasion resistant impact surface which is uppermost in use and being adapted to be removably securable over the apex of a crusher distribution plate or a crusher cone, by means of securing means positioned on the underside of the wear cap, being that side of the wear cap which in use lies adjacent to the apex of the crusher distribution plate or crusher cone; said wear cap being sized so that the periphery of the wear cap extends beyond the apex of the crusher cone or distribution plate.

The wear cap may be made of any of a range of tough abrasion resistant materials e.g. tungsten steel, abrasion resistant plastics materials (including polyplastics), hardwoods such as ironwood, rubber composites, or abrasion resistant ceramics or ceramic composites.

Good results have been obtained using a wear cap with a mild steel base in which the surface which is uppermost in use (i.e. the impact surface) is coated with a high magnesium steel, which is very abrasion resistant and also is impact resistant. Another suitable material is a substrate of mild steel with tungsten steel inserts or a top coating of tungsten steel over the impact surface. Inserts of abrasion resistant ceramics or ceramic composites also may be used on the impact surface.

The wear cap may be any of a wide range of shapes e.g. circular in plan or rectangular/square in plan, or oval in plan, or multisided in plan.

Brief Description of Drawings By way of example only, two embodiments of the present invention are described, with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic cutaway view of a BARMAC crusher;

Figure 2 is a diagrammatic cutaway of a detail of the crusher of Figure 1;

Figure 3 is a diagrammatic sectional view of a cone crusher;

Figure 4 is a sectional side view of the centre portion of Figure 2, but with a wear cap in accordance with the present invention fitted;

Figure 5 is a diagrammatic sectional view similar to that of Figure 3, but with the wear cap of the present invention fitted; Figure 6 is a plan view of one embodiment of a wear cap in accordance with the present invention;

Figure 7 is a plan view of another embodiment of a wear cap in accordance with the present invention.

Figure 8 is a side view of a variation of a securing means for a wear cap; and

Figure 9 is an isometric view of the underside of a wear cap.

Best Mode for Carrying Out the Invention Referring to Figures 1, 2 and 4, a wear cap 40 is fitted over the apex of the distribution plate 20.

As shown in Figure 4, the wear cap 40 consists of a head portion 41 which is circular in plan and has a rounded upper surface 42. The lower surface has a stem 43 welded to the centre; the stem 43 is formed with an exterior screw thread so that it can be firmly and rigidly secured to the head of the bolt 44 which holds the distribution plate 20 onto the upper end of the spindle 15.

The diameter X of the wear cap 40 is selected such that the outer perimeter of the wear cap overhangs the upper portion of the distribution plate 20, as shown in Figure 4.

In use, the presence of the wear cap 40 means that rocks entering the crusher and directed downwards onto the distribution plate 20 impinge initially on the wear cap 40 rather than on the top of the distribution plate 20. This helps to spread the incoming rocks over the whole of the distribution plate 20, and also prevents impact damage on the top of the distribution plate 20 and on the bolt 44 which secures the distribution plate 20 to the spindle 15.

The use of the wear cap 40 significantly reduces the wear on the distribution plate 20 and thus greatly increases the service life of the distribution plate. Typically, the service life of the distribution plate 20 for a crusher in heavy use can be extended from about two weeks to about seven to eight weeks, by the addition of the wear cap 40.

Since replacing the distribution plate involves significant downtime for the crusher, any increase in the service life of the distribution plate is a considerable practical advantage. In addition, the work of replacing the wear cap 40 is significantly easier and quicker than replacing the distribution plate 20:- the time required is typically a few minutes compared to several hours. A further advantage is that the wear cap 40 is a much cheaper component than the distribution plate.

Referring to Figures 3 and 5, a cone crusher 30, of the type which has the feed plate 31A of the cone 31 exposed, can also be fitted with a wear cap 40 in accordance with the present invention. As described with reference to the BARMAC type of crusher, the wear cap 40 is sized so that the outer perimeter of the wear cap overhangs at least the upper portion of the feed plate 31A.

The wear cap is fitted by boring a screw-threaded mounting hole in the centre of the apex of the feed plate, and screwing the stem 43 of the wear cap 40 into the hole. The use of the wear cap on a cone crusher significantly extends the working life of the feed plate 31A, with a corresponding reduction in the expense of providing replacement feed plates and in the down time required to remove and replace the feed plate. The wear cap 40 is a cheaper component than the feed plate, and can be replaced much more quickly and easily.

As an alternative to the securing means for the wear cap as shown in Figures 4 and 5, the arrangement shown in Figure 8 is preferred. As shown in Figure 8, a nut 50 which is formed with an internal screw thread, is welded to the centre of the underside of a wear cap 51, with the longitudinal axis A - A of the nut 50 perpendicular to the plane of the underside of the wear cap 51.

The bolt 44 is the bolt described with reference Figure 4, which holds the distribution plate 20 onto the upper end of the spindle 15. An externally screw threaded shaft 52 is rigidly secured to the head of the bolt 44 at its lower end; the upper end of the shaft 52 can be screw threaded the engaged with the screw thread on the interior of the nut 50. This construction means that the wear cap 51 can be quickly and easily replaced simply by rotating the wear cap 51 to unscrew it from the shaft 52. A fresh wear cap is then threaded into place.

An equivalent arrangement for a cone crusher is to provide a screw threaded mounting hole in the centre of the apex of the feed plate, as described with reference to Figure 5, and then screwing an externally threaded shaft into the mounting hole; a wear cap fitted with a nut 50 as described above can then be screwed onto the externally threaded shaft.

The wear cap used with either the BARMAC crusher or the cone crusher can vary in plan view:- it may be circular in plan as shown in Figure 6 or a rounded rectangular shape as shown in Figure 7, or square in plan or oval. Other shapes may also be used e.g. multi-sided. The actual dimensions of the wear cap depend upon the dimensions of the distribution plate or cone with which it is to be used:- as described above, the wear cap should be sized to overhang the adjacent portion of the distribution plate/cone, typically at least 20 millimetres.

To make it easier to unscrew the wear cap from engagement with the distribution plate or from the feed plate of a cone crusher, preferably the underside of each wear cap is formed as shown in Figure 9:- a series of equidistantly spaced slots 55 are formed on the underside 56 of the wear cap 51. The slots 55 do not penetrate the upper surface of the wear cap. The size and shape of the slots 55 are not important:- they simply provide purchase for a hand or for a tool so that the wear cap can be gripped to rotated relative to the distribution plate/feed plate as the case may be.

Claims

Claims 1. A wear cap for use in combination with a top feed crusher, said wear cap providing an impact resistant and abrasion resistant impact surface which is uppermost in use and being adapted to be removably securable over the apex of a crusher distribution plate or a crusher cone, by means of securing means positioned on the underside of the wear cap, being that side of the wear cap which in use lies adjacent to the apex of the crusher distribution plate or crusher cone; said wear cap being sized so that the periphery of the wear cap extends beyond the apex of the crusher cone or distribution plate.
2. The wear cap as claimed in Claim 1 wherein the shape of the wear cap in plan is selected from the group consisting of: circular, oval, square, rectangular, multisided.
3. The wear cap as claimed in Claim 1 or Claim 2, wherein said securing means includes an externally threaded shaft rigidly secured to the centre of the underside of the wear cap, with the longitudinal axis of said shaft perpendicular to the plane of the underside of the wear cap.
4. The wear cap as claimed in Claim 1 or Claim 2, wherein said securing means includes an internally threaded nut rigidly secured to the centre of the underside of the wear cap, with the longitudinal axis of said nut perpendicular to the plane of the underside of the wear cap.
5. The wear cap as claimed in any one of the preceding claims, wherein the wear cap is made from a material selected from one of the following: tungsten steel, mild steel coated with tungsten steel on the impact surface thereof, abrasion resistant plastics materials, hardwoods, rubber composites, mild steel coated with high magnesium steel on the impact surface thereof, abrasion resistant ceramics or ceramic composites, steel provided with ceramic inserts on the impact surface thereof, steel provided with tungsten steel inserts on the impact surface thereof.
6. The combination of the wear cap as claimed in any one of the preceding claims and a rotary crusher.
7. The combination of the wear cap as claimed in any one of the preceding claims and a cone crusher.