To protect the mechanical and structural parts of crushers from damage caused by the hard and abrasive nature of the product material, most crushers have hard, abrasion resistant liners. These are placed to line the mechanical and structural parts so that the latter are not in direct contact with the product. In jaw crushers, such items are called fixed jaw and swing jaw liners. Gyratory crushers are fitted with a head (mantle) and bowl liners. The liners are made from a number of wear resistant materials, including elastomers and ceramics. However, for most crushers, they are made of metal. Common materials include 12 - 14% manganese steel, also known as Hadfield steel. Hardened high alloy steel and white irons known as Super-chrome and Ni- hard are all common. Special hard facings, commonly high carbon and chrome alloys, are sometimes used to extend liner life. In each case the actual material selected for liners is chosen to best suit operational performance at acceptable cost.

When liners wear out, the worn liners are discarded and new liners are fitted. To permit liner replacement the crusher and its associated feed and discharge systems must be shut down and therefore liner change is always attended by loss of production. It is thus vital that the worn liners are removed quickly and replaced easily with new liners using available on site labour.

The materials from which liners are made are hard and abrasion resistant and some of them become harder, by work hardening, when gouged or distorted by the material which the crusher is reducing. These characteristics make it difficult and expensive to machine them with metal cutting equipment and there is limited accuracy which metal cutting (and grinding) processes can achieve.

On the other hand the liners are not, first and foremost, structural members and the crushing forces must be transferred to them from the mechanical and structural crusher parts which the liners protect. To transfer these crushing forces which are, by their nature, distributed widely over the liner surfaces, intimate contact is needed between the back of the liners and the adjacent mechanical and/or structural components of the crusher. It follows that an ideal liner will have a back surface exactly matching the shape of the crusher parts it protects. The liners however resist such accurate machining. Any machining, regardless of accuracy, is very time consuming and expensive. Traditionally this incompatibility is resolved in gyratory crushers by fitting liners, with little or no machining, to the mechanical and structural parts of the crusher which they protect, leaving an annular gap between each liner and the structural part of the crusher which the liner protects. After assembly, the gap is filled completely by pouring in a low melting point metal such as lead, zinc or a babbit metal or a resinous glue such an epoxy. Thus, each liner is made integral with its structural part. This traditional method achieves full support of the liner and full contact with the crusher parts, and it works very well. The disadvantage is that subsequent removal of a liner from its structural part is very difficult and the pouring process requires acquired skills not always available on site. The replacement of liners using this method takes days rather than hours and adds greatly to the time the crusher is out of service.

The invention provides an improved method and arrangement for providing a liner for a structural part of a gyratory crusher. The invention is particularly well suited for use in relation to structural parts of gyratory crushers of the type disclosed in Australian Patent 618545 (AU-B-19935/88), and largely is described in this context. However, it is to be understood that the invention also can be used for other types of gyratory crushers.

Replacement of crusher liners is required: a) when the liners are worn to the point where they may fail and thereby expose the underlying crusher parts to damage from the material being crushed; and b) when the liners still retain structural integrity and strength but have worn so that the surfaces in contact with the product have lost geometry critical to the control of grade or size, which the operator desires.

The present invention facilitates replacement of liners of gyratory crushers at such times in a manner substantially reducing overall capital costs and the costs of down-time and labour required for replacement.

A gyratory crusher according to the invention includes a bowl defining a chamber for receiving frangible or friable material to be crushed, and further defining a discharge opening at the base thereof through which crushed material is able to discharge. The crusher also includes a crushing head mounted in the bowl at an offset position with respect to a central axis of the bowl, and a drive assembly for driving the crushing head within the bowl for imparting gyratory motion to the head about a gyratory axis inclined with respect to and intersecting the central axis. The arrangement is such that frangible or friable material received into the chamber is subjected to crushing between an inner peripheral surface of the bowl and an outer peripheral surface of the head by the gyratory motion of the head.

The bowl comprises a first assembly, having an outer peripheral member which is a structural part of the crusher and an inner peripheral member which is co-axially mounted within the outer member and defines a bowl liner. The head comprises a second assembly, having an outer peripheral member which defines a head liner, and an inner peripheral member which is a structural part of the crusher and on which the head liner is co-axially mounted. The arrangement is such that in at least one assembly, of the first assembly and the second assembly, its members are configured such that they are able to be moved into or out of co-axial relationship by relative axial movement therebetween, with the one assembly including means releaseably retaining its members in assembly.

Most preferably the arrangement of each of the first and second assemblies is as detailed in the immediately preceding paragraph herein.

In a first arrangement, the at least one, but most preferably each, assembly has a liner which is of composite form in which it has a filler formed thereon, around a peripheral surface thereof which faces the respective structural part. Thus, in the case of the first assembly comprising the bowl, the bowl liner has a filler formed around its outer surface. Conversely, in the case of the second assembly comprising the head, the head liner has a filler formed around its inner surface. In each case, the filler most preferably is formed such that it closely conforms with an opposed surface of the respective structural member; that is, an inner surface in the case of the outer peripheral member of the bowl and an outer peripheral surface in the case of the inner member of the head. Where such composite form of liner is provided, it is such that the weight of the liner urges the filler towards the opposed surface of the respective structural member, preferably such that there is frictional contact between the filler and that opposed surface. Where such frictional contact is achieved, the filler at least in part comprises the retaining means for releaseably retaining the liner and its structural member in assembly. However the retaining means additionally or alternatively may include a clamp system having a clamp plate, ring or the like which is secured to one of the liner and its structural member, such as by bolts, so as to bear against the other one of the liner and its structural member, to secure the liner and its structural member in assembly.

In a second arrangement, the at least one, but most preferably each, assembly has a liner which does not include a filler. In that arrangement, the retaining means may comprise a clamp system having a clamp plate, ring or the like which is secured to one of the liner and its structural member, such as by bolts, so as to bear against the other one of the liner and structural member to secure them in assembly.

Where the retaining means comprises or includes a clamp system, the latter most preferably acts substantially axially with respect to the liner and its structural member to urge them into engagement. Preferably each of opposed surfaces of the liner and its structural member define a respective annular

shoulder, with the retaining means acting to bring the shoulders into firm contact. The shoulders may be at or near one of respective axial ends of the assembly of the liner and its structural member, with the retaining means at or adjacent to the other end. The invention also provides a method for providing a replaceable liner for use in a gyratory crusher according to the invention. The liner may comprise a bowl liner for use with the structural member of a bowl comprising the first assembly, or a head liner for use with the structural member of a head comprising the second assembly. In one form of the method, the liner is provided with a filler, over a peripheral surface thereof which is to be opposed to a mating peripheral surface of the structural member. For this, the liner is assembled in relation to a suitable mould which defines a mould surface providing a replica of the mating surface of the structural member, and fill material is then poured into a fill cavity between the liner and the mould. After the fill material has set (in the case of a resin) or solidified (in the case of a metal) to provide a filler, the liner and filler are together separated from the mould, to provide a composite liner with integral filler ready for mounting to the structural member of the crusher.

The mould used in the process is required to have a mould surface which defines a relatively accurate replica of the mating surface of the structural member but, otherwise, need not be a replica of the structural member. The material of which the mould is made can vary substantially, but depends in part on whether the fill material is a resin or a metal. Also, it of course is required that the mould material is such that it is amenable to separation of the liner/filler composite from the mould.

Where the filler material is a resin, any suitable material can be used for the mould. Thus, in that case, the mould can, for example, be made of glass-fiber reinforced resin, or it can be made from a metal by casting and/or machining. In each case, the mould preferably is coated with a suitable stripping agent, such as wax, prior to a liner being assembled in relation to the mould. Alternatively, the mould can be made of a suitable plastic material with which a resin to comprise the filler material does not bond. Additionally, in the case for example of a metal

mould, the mould can be provided with a coating of such plastic material to provide, in effect, a permanent or semi-permanent stripping agent integral with the mould.

Where the filler material is a metal, such as lead, zinc or babbit metal, the mould necessarily needs to be of a material which is able to withstand the temperature at which such metal is to be poured and which also enables separation of the liner/filler composite. The mould for use with a metal filler can itself be of a metal, such as steel, which has a melting point sufficiently above that of the filler metal. Alternatively, a sand mould can be used. Separation of the liner/filler composite from the mould may be simply by stripping the composite from the mould, with the then exposed filler surface optionally then cleaned of any stripping agent. However, in the case of a sand mould, separation more typically is achieved by breaking up the mould to allow it to fall away from the composite. In the latter, the then exposed liner surface may be brushed, wiped or subjected to a pressurised air jet to remove any debris.

Crushers with which the composite liner/filler produced by the process of the invention can be used are fitted with similar composites. When a liner of the crusher needs replacement, due to wear, an operator simply removes the composite comprising the worn liner/filler from its structural member and fits a new composite. The new composite may have a filler formed to such accuracy as to provide good engagement with the mating surface of the structural member, so as to retain the new composite in relation to the structural member. Alternatively, or additionally, the new composite may be retained in assembly with the structural member by fitting or reapplying a clamping system as detailed above.

In an alternative method of the invention, a liner for the crusher is formed such that, over at least an annular part of a surface thereof which is to be opposed to a surface of a respective structural member of the crusher, it defines a shoulder which is substantially complementary in form to a shoulder defined by the surface of the structural member. Also, a further surface of the liner, such as an axial end surface, is formed such that it defines a bearing surface which faces oppositely to the shoulder thereof. The bearing surface either is such that it is

adapted to be engaged by retaining means to be mounted on its structural member, or is adapted to have the retaining means mounted thereon for engaging the structural member, such that the restraining means is operable to urge the liner axially relative to the structural member for engagement between the respective shoulders.

The liner may be cast so as to achieve the required form. However, it additionally can be ground and/or machined at the shoulder and/or the bearing surface.

In order that the present invention may more readily be understood, description now is directed to the accompanying drawings, in which:

Figure 1 is a sectional view through a gyratory crusher having structural parts provided with liners in accordance with known practice;

Figure 2 is a sectional view of a head for a gyratory crusher based on use of the present invention; Figure 3 is a half-section of a bowl for a gyratory crusher base on use of the present invention;

Figures 4 and 5 show respective components for the head of Figure 2; Figures 6 and 7 show respective components for the bowl of Figure 3; Figures 8 and 9 show respectively alternative forms of head liner and head bearing housing for use in the invention;

Figure 10 shows a sectional view of a crusher having a head comprising the liner of Figure 8 and the bearing housing of Figure 9; and

Figure 11 shows a sectional view of a crusher having an alternative bowl suitable for application of the present invention. Figure 1 shows a gyratory crusher 10 produced in accordance with known practice. Much of the construction and operation of the crusher 10 readily will be understood. Accordingly, on broad detail is provided.

The crusher 10 has a bowl 12 and a head 16. The bowl 12 is mounted on a fixed, bowl support frame 19. As shown, the bowl 12 is of circular transverse cross-section, and converges frusto-conically from its open upper end to a constriction at 20, and thereafter diverges frusto-conically to its open lower end.

The bowl 14 comprises a main annular body 13 which forms a structural part of

the crusher 10 and, co-axially within the body 13, a bowl liner formed of annular liner parts 14 and 14a.

The head 16 also is circular in transverse section and comprises an inner annular bearing housing 17 which forms a structural part of the crusher 10 and, and co-axially on the housing 17, a head liner formed of annular liner parts 18 and 18a. The outer periphery of the head 16 diverges slightly from its upper end to a region below the construction 20, and thereafter flares downwardly and outwardly to provide a skirt portion 16a.

The crusher 10 includes an eccentric shaft 28 on which head 16 is rotatably mounted. The shaft 28 has a lower portion 28a and an upper portion 28b each of which has a common axis of rotation which is substantially co¬ incident with the axis of bowl 12. The shaft portion 28a is rotatable in an upper bearing assembly 30 and a lower bearing assembly 30a, with each of the assemblies 30 and 30a located in lower support frame 19a which can form part of the frame 19. The shaft portion 28b is rotatable in an upper bearing assembly 31 and a lower bearing assembly 31a, with each of the assemblies 31 and 31a located in super-structure 19b mounted above the support frame 19. The shaft 28 also has an intermediate portion 28c which has an axis which is inclined with respect to the common axis of the shaft portions 28a and 28b, with the respective axes of the shaft portions 28a and 28c intersecting at a fixed point P which is on or closely adjacent to a basal plane of the head 16. That is, point P is so located relative to a plane containing the lower peripheral extremity of the skirt portion 16a. The head 16 is mounted co-axially on shaft portion 28c by means of an upper bearing assembly 32 and a lower bearing assembly 32a, with each of the assemblies 32 and 32a being concentric with and provided between the shaft portion 28c and the housing 17 of the head 16.

The shaft 28 is driven, so as to rotate on the common axis of its lower and upper shaft portion 28a and 28b, by drive assembly 34 mounted on structure 19b. The assembly 34 has a drive shaft 36 by which drive is imparted to shaft 28 for rotating the latter.

In operation of the crusher 10, the drive assembly 34 rotates the shaft 28 on the axis of its lower and upper portion 28a and 28b. As the axis of the

intermediate shaft portion 28c is inclined to the axis of shaft portion 28a and 28b, and as head 16 is co-axially mounted on portion 28c, rotation of the shaft 28 on the axis of its portions 28a and 28b causes head 16 to gyrate about the fixed point P. Moreover, as the lower end of head 16 is located proximate to, or coincident with point P, the gyratory motion of head 16 is such that movement of its upper end is predominantly transverse to the axis of bowl 12 and such that movement of the lower end of head 16 is substantially parallel to the axis of bowl 12.

Material to be crushed is fed into the upper end of bowl 12, to a crushing chamber 38 defined within the bowl 12 around the head 16. The movement of the head 16, during rotation of the shaft 28, provides a crushing action in which, where the gap between the crushing surface 40 of bowl 12 and head 16 is a minimum at the upper end of the chamber 38, as shown to the left of head 16, the gap is: - a maximum at the diametrically opposed side of the head 16 at the upper end of chamber 38;

- a maximum at the lower end of chamber 38, at the left side of the head 16; and

- a minimum at the lower end of chamber 38, at the right side of head 16. Furthermore, as shaft 28 rotates, the gyratory motion of head 16 causes the location of the upper maximum and minimum gap openings, and of the lower minimum and maximum gap openings, to be in successive diametrical planes of bowl 12. Thus, after rotation of shaft 28 through 180° from the position shown in Figure 1 , there will be a maximum gap at the top left and lower right sides of head 16.

With further reference to Figure 1 , the bowl 12 and the head 16 are each of integral construction. That is, liner parts 14 and 14a initially are formed separately from body 13, but then:

(i) part 14a is assembled in relation to body 13, for example in a jig, and filler material is poured into a cavity between part 14a and body 13 to form filler 44a; and

(ii) part 14 is assembled in relation to body 13, such as in the jig, and filler material is poured into a cavity between part 14 and body 13 to form filler 44.

On setting or solidification of the filler material to provide filler 44 and 44a, body 13 and liner parts 14 and 14a comprise an integral structure with body 13. A similar procedure and result is necessary with housing 17, liner parts 18 and 18a and filler 45 of head 16.

Of course the procedure for bowl 12 can be simplified. Thus bowl 12 may have a single part liner or, like head 16, it may have mating liner parts, necessitating only a single pouring of filler material. However, even with this simplification, the structural part and its liner still need to be set up accurately, such as by use of a jig, and filling material poured to form an integral component. As a consequence there is substantial time, effort and cost involved when replacement of a worn liner is required. One procedure for replacing a worn liner of bowl 12 or head 16 necessitates fracturing the worn liner so that it can be removed in fragments. For this, it often is necessary to cut lines of weakness in the worn liner, such as by thermal cutting. An alternative procedure is to apply high axial forces, using jacks, to force off the worn liner; with it generally being necessary to heat the worn liner so as to at least soften the filler bonding the liner to its structural member. Assuming that the selected procedure does not damage the structural member so as to preclude its re-use, it is necessary after removing the worn liner then to remove adherent filler from the structural member, such as by grinding in the case of a resin filler or machining in the case of a metal filler. Finally, the structural member and a new liner have to be accurately assembled together, for the difficult task of pouring fresh filler material therebetween.

With reference to Figure 2, there is shown an improved form of head 116, in which parts correspond to those of Figure 1 have the same reference numeral, plus 100. The head 116 comprises a housing 117, a liner 118 and filler 145 between the housing 117 and the liner 118. Also, head 116 includes a top ring 46 which is secured to the top peripheral edge of housing 117 by bolts 48, and overlaps and secures liner 118 at its top edge.

With removal of bolts 48 and ring 46, liner 118 and filler 145, as a composite structure, are separable from housing 117. This is possible because the composite is produced in the form shown in Figure 5 and then axially received on a housing 117 as shown in Figure 4. To produce the composite of liner 118 and filler 145, a mould 50 as shown in Figure 5 is used. The mould 50 has an external surface which is a replica of the peripheral surface of housing 117. That external surface of the mould 50 is coated with a release or stripping agent after which filler material is poured into a cavity between the liner 118 and the mould 50, and allowed to set or solidify to form filler 145.

The composite then is stripped from mould 50 and is able to be used, when required, for a replacement in a crusher having a worn head liner 118.

A similar procedure is used for producing a composite bowl liner 114 and filler 144 as shown in Figure 7, for use with a bowl body 113 as shown in Figure 6, for a bowl 112 as shown in Figure 3. That is, filling material is poured against the liner 114, using a mould 52 as shown in broken outline in Figure 7, to form filler 114. The mould 52 has an internal peripheral surface which is a replica of the internal peripheral surface of the body 113, such that the composite of liner 114 and filler 144 is able to be used, when required, for replacement of a worn liner 113 of a crusher.

Figures 8 to 10 illustrate an alternative arrangement and procedure for the head 216 of a crusher 210. Much of the detail of crusher 210 will be readily understood from the description directed to crusher 10 of Figure 1. However, the crusher 210 differs in two significant respects, as briefly outlined in the following. The first difference is that rotation of shaft 228 is by means of a bottom drive assembly 50, utilising a drive motor (not shown). The assembly 50 has a drive shaft 52 mounted in support frame 219a by inner bearing assembly 54 and outer bearing assembly 54a. A pinion 56 is mounted on the inner end of shaft 52, and meshes with a crown wheel 58 secured around portion 228a of the shaft 228. A pulley 60 on the outer end of the drive shaft 52 enables the shaft 52 to be rotated by operation of the motor, via drive belts (not shown), for rotation of the shaft 228.

The second difference is in the form of shaft 228 itself. As shown, the shaft 228 has a lower portion 228a which has an axis of rotation co-incident with the axis of bowl 212. However, its upper portion 228c corresponds to intermediate portion 28c of the shaft 28 of Figure 1 , and has an axis which is inclined to the axis of portion 228a, with the axes of the portions 228a and 228c intersecting at point P. The shaft 228 does not have a third portion which projects above head 216 and corresponding to portion 28b of shaft 28 of Figure 1. However, the gyratory motion of head 216 is essentially the same as for head 16 of Figure 1. Reverting now to the alternative arrangement for the head 216 of the crusher 210, the form of its structural member comprising bearing housing 217 is as shown in more detail in Figure 9. The housing has an outer peripheral surface 217a which has a slight frusto-conical outward taper from top end-face 217b and, adjacent the lower end, is stepped at a shoulder 217c to maintain a wall thickness sufficient to enable an internal step 217d for accommodating bearing assembly 232a. The housing also has at its lower end a radially outwardly extending flange 217e which defines a shoulder 217f. The housing 217 preferably is used substantially in its as-cast form. However, the end-face 217b and the shoulder 217f most preferably are machined to provide substantially flat, radial bearing surfaces.

The head liner 218 is of integral cast form. As shown in Figure 10, the liner 218 has an upper frusto-conical part 218a and a lower frusto-conical part 218b. The external surface part 218a tapers slightly outwardly from a top end face 218c, while the external surface of part 218b continues the taper but at a significantly greater cone-angle, such that part 218b flares outwardly from part 218a. The internal surface 218d of liner 218, over a major part of its axial extent, follows the external taper of part 218a. The taper of surface 218d is such that liner 218 is able to be axially received, downwardly on to housing 217. Also, surface 218d is stepped to accommodate the shoulder 217c of housing 217, and to provide a downwardly facing radial shoulder 218e. Below the shoulder 218e, surface 218d follows the frusto-conical taper of the external surface of part 218b.

The liner 218 is used substantially in its as-cast form. However, the end- face 218c and the shoulder 218e most preferably are machined or ground to provide substantially flat, radial bearing surfaces. The axial extent of the liner 218 is such that it is supported by its shoulder 218e resting on shoulder 217f of the housing 217. Also, when so received, end-face 218c of liner 218 preferably is closely adjacent, most preferably slightly below, end-face 217a of the housing 217.

The liner 218 and the housing 217 are cast within tolerances which ensure that the liner 218 is able to be axially received, and removed from, the housing 218 without interference. However, it is preferred that surface 218c is a relatively close fit around the outer surface 218a of the housing 218, particularly at the upper part of the head 216.

The head 216 of the crusher 210 further includes a cap 66 of inverted cup- shaped form. The cap has a stepped bottom peripheral face which defines a lower outer rim 68a and a recessed inner rim 68b. Bolts (not shown) pass downwardly through cap 66, around its periphery, through bores which open at rim 68b. The bolts engage in threaded bores 64 in the end face 217a of the housing 217 (see Figure 9), to retain the cap in portion. The bolts are tightened, to draw cap 66 down, and thereby force its rim 68a onto face 218c of the liner 218, and force shoulder 218e of the latter into firm engagement with shoulder 217f of the housing 217.

Figure 10 does not provide detail in relation to bowl 212 of crusher 210. However, the arrangement may be similar to that shown in Figure 11.

In Figure 11 , there is shown a crusher 310 of which the general arrangement and working will be understood from a consideration and comparison of Figures 1 and 10. Accordingly, description will be limited to the detail of bowl 312, as illustrated principally on the right side of Figure 11.

The bowl 312 has an outer peripheral member 313 which is structural part of the support frame 319, and a liner 314. The member 313 is of cylindrical form and is provided with an external thread formation 313a by which it is secured in relation to a surrounding part of the housing 319. The internal peripheral surface

313b of the member 313 is of uniform circular section, except for a radially

inwardly extending flange 313c at the lower extent of the surface 313b. The axially upper face of the flange 313c and the top face 313d of member 313 are machined flat, with member 313 otherwise being in its as-cast condition.

The liner 314 is of somewhat arcuate form in diametrical section. However, on its outer face 314a, it defines an upper radial boss 314b, and a lower radial flange 314c. The axially lower face of boss 314b and the axially upper face of flange 314c are ground or machined such that each is substantially flat and spaced by substantially the same axial distance as that between the machined faces of member 313. Liner 314 is axially received in member 313 such that the flat face of flange

314c rests on the flat face of flange 313c and the flat face of boss 314b rests on top face 313d of member 313. A respective bolt 70 then is passed through each of a plurality of angularly spaced bores 72, which extend from the inner to the outer surfaces of liner 314; with each bolt 70 engaging in an aligned bore in member 313. The bolts 70 are tightened to secure member 313 and its liner 314 in assembly, with the contacting faces forced securely against each other.

Finally, it is to be understood that various alterations, modifications and/or additions may be introduced into the constructions and arrangements of parts previously described without departing from the spirit or ambit of the invention.