Patent Publication Number: US-2016236198-A1

Title: Gyratory crusher bottom shell assembly and arm liners

Description:
FIELD OF INVENTION 
     The present invention relates to a gyratory crusher bottom shell and a bottom shell assembly in which support arms that extend radially to mount a central hub of the bottom shell are shaped and/or configured to provide a seat to at least partially accommodate respective arm liners to provide a secure and effective means of mounting the liners at the bottom shell. 
     BACKGROUND ART 
     Gyratory crushers are used for crushing ore, mineral and rock material to smaller sizes. Typically, the crusher comprises a crushing head mounted upon an elongate main shaft. A first crushing shell is mounted on the crushing head and a second crushing shell is mounted on a frame such that the first and second crushing shells define together a crushing chamber through which the material to be crushed is passed. 
     The gyratory pendulum movement of the crushing head is supported by a lower bearing assembly positioned below the crushing head and a top bearing into which an upper end of the main shaft is journalled. The main shaft and lower bearing are typically mounted within a central hub supported at the bottom shell by radially extending arms. These support arms and the radially inward facing surface of the bottom shell are protected from the material as it falls through the bottom shell by wear resistant liner plates. Example protective liners are described in U.S. Pat. No. 2,860,837; U.S. Pat. No. 3,150,839; U.S. Pat. No. 4,065,064. 
     However, existing bottom shells and arm liners are disadvantageous for a number of reasons. Firstly, it is conventional for the liners to be supported exclusively by attachment bolts that secure radially outer parts of the arm liner to the bottom shell wall to suspend the liner above the support arm. Conventionally, the bottom shell support arms are angled downwardly from the shell wall to the central hub such that if the attachment bolts fail the liner falls radially inward to the hub and becomes dislodged from the arm. According to the conventional arrangements, the attachment bolts are required to both withstand the significant impact forces resultant from the contact with material as it falls through the bottom shell and support the arm liner in a complete or partial cantilever arrangement. Secondly, conventional arm liners, due in part to the configuration of the support arms, are angled axially downward towards the hub. This is disadvantageous as material is thrown radially inward towards the hub resulting in wear to both the hub and associated seals and dust collars. Accordingly, what is required is a bottom shell and bottom shell liner assembly that addresses the above problem. 
     SUMMARY OF THE INVENTION 
     It is an objective of the present invention to provide a gyratory crusher bottom shell and a bottom shell assembly (including a plurality of support arm liners) that is configured to reliably and efficiently mount the support arm liners to both reduce the tensile force within the attachment bolts and to ensure the support arm liners are provided with a redundancy seated position in the event that the attachment bolts fail so as to retain the liners at the support arms. It is a further specific objective to configure the arm liners for the desired and efficient deflection of material passing through the bottom shell without deflecting a majority component of the material radially inward to the central hub. A stronger more reliable means of mounting support arm liners is desired. 
     The objectives are achieved, by specifically configuring the shape and configuration of the support arms that extend radially between the lower region of the shell wall and the central hub. In particular, an axially upper region (or surface) of each arm comprises a trough, seat or saddle region that is positioned axially below an axially uppermost part of the hub so as to accommodate at least a part of the arm liner. In such a configuration, the liner nestles within the seat and is capable of being supported exclusively by the contact with the seat. Accordingly, the present arrangement is advantageous to distribute the mass of the liner in a radial direction between the hub and the shell wall and to reduce the support loading at the radially outer attachment bolts that secure the arm liner to the bottom shell. According to the present configuration, the arm liner is supported both at or towards its radially innermost region and its radially outermost region. Supporting the liner via a dip or recess positioned at a radially inner region of the arm is beneficial to prevent the liner from becoming completely dislodged from the arm should the attachment bolts fail. 
     The present configuration is further advantageous in that the recess or seat enables an uppermost surface of the arm liner (that contacts the material falling through the bottom shell) to be ‘less inclined’ than existing liner arrangements and to extend in a horizontal or near horizontal plane to avoid undesirable deflection of material towards the central hub. The present arrangement therefore allows a significant part of the radial length of the liner to be positioned at, below or slightly above an uppermost part of the hub. 
     According to a first aspect of the present invention there is provided a gyratory crusher bottom shell assembly comprising: an outer wall extending around a longitudinal axis, the wall having radially outer and inner facing surfaces; an inner hub positioned radially within the wall and surrounded by a part of the inner facing surface; a plurality of support arms extending radially to connect the wall and the hub, each arm having an axially upward facing surface that extends generally axially downward from the inner facing surface of the wall towards the hub at a radially outer section of the arm, the upward facing surface at a radially inner section of the arm extending generally axially upward to mate with the hub wherein a region of the upward facing surface is positioned axially lower than an axially uppermost end surface of the hub to define a seat; a plurality of arm liners positioned over the respective arms, each liner having an upward facing surface capable of contacting material passing through the bottom shell assembly and an underside surface positioned opposed to the upward facing surface of the arm; characterised in that: each of the liners comprises a shape and configuration such that a part of the underside surface of the liner is in contact with the upward facing surface of the arm at the seat to at least partially mount each of the liners at the respective arms. 
     Preferably, the seat comprises a curved shape profile in a radial direction between the wall and the hub. Advantageously, the upward facing surface of the arm slopes gradually downward towards the seat (or recess) from the shell wall and slopes gradually upward from the seat towards the central hub. Such a configuration provides a saddle region at the support arm that encourages the liner to be ‘self-seating’ into the saddle in the event that the attachment bolts fail. 
     Optionally, the seat is positioned radially closer to the hub than the wall. Such an arrangement is further advantageous to prevent the liner from becoming dislodged from the arm and to be retained at the bottom shell. 
     Preferably, in an axial plane extending along the radial length of each arm, a radial length (B) of the seat is in a range 30 to 90% of a radial distance (A) between a radially outermost part of the uppermost end surface of the hub and the outer facing surface of the wall at an axial position coplanar with said uppermost end surface. Accordingly, the present radial length of the seat ensures a majority of the radial length of the liner is supported by the seat region to be stabilised over the majority of the liner radial length. Preferably, this range is 40 to 80%; 45 to 65%; 48 to 60%; and more preferably 53 to 57%. 
     Optionally, in an axial plane extending along a radial length of each arm, a radial length (B) of the seat is in a range 50 to 100% of a radial length (C) of the respective liner extending in the direction between the wall and the hub. Optionally, said range of said length of the seat to the length of the liner is 65 to 90%. 
     Optionally, in an axial plane extending along a radial length of each arm, a radial length (D) of the liner occupied within the seat is in a range 10 to 80%. More preferably, said range is 30 to 70%; 40 to 60%; or 45 to 55%. The respective radial lengths of the liner and seat region are advantageous to i) distribute the mass of the liner along the support arm, ii) provide the required deflection direction of material passing through the bottom shell and iii) provide a means for the secure seating of the liner at the arm in the event of failure of the primary attachment bolts. 
     According to a second aspect of the present invention there is provided a gyratory crusher bottom shell comprising: an outer wall extending around a longitudinal axis, the wall having radially outer and inner facing surfaces; an inner hub positioned radially within the wall and surrounded by a part of the inner facing surface; a plurality of support arms extending radially to connect the wall and the hub, each arm having an axially upward facing surface that extends generally axially downward from the inner facing surface of the wall towards the hub at a radially outer section of the arm, the upward facing surface at a radially inner section of the arm extending generally axially upward to mate with the hub wherein a region of the upward facing surface is positioned axially lower than an axially uppermost end surface of the hub to define a seat; characterised in that: in an axial plane extending along the radial length of each arm, a radial length (B) of the seat is in a range 30 to 90% of a radial distance (A) between a radially outermost part of the uppermost end surface of the hub and the outer facing surface of the wall at an axial position coplanar with said uppermost end surface. 
     Optionally, the radial length of the liner occupied within the seat is in the range 30 to 70%. Preferably, the range of the radial length (B) to the radial distance (A) is 40 to 80%; 45 to 65%; 48 to 60%; and more preferably 53 to 57%. Optionally, the seat is positioned radially closer to the hub and the wall and the seat comprises a curved shape profile in a radial direction between the wall and the hub. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which: 
         FIG. 1  is a perspective view of a gyratory crusher bottom shell having a modular wear resistant liner positioned internally within the bottom shell to protect both the internal surface of the shell and support arms that extend radially between the shell wall and a central hub that mounts the crusher main shaft and part of the drive components according to a specific implementation of the present invention; 
         FIG. 2  illustrates the bottom shell and protection liner assembly of  FIG. 1  with one of the protective arm liners removed for illustrative purposes; 
         FIG. 3  is a cross section through E-E of  FIG. 2 ; 
         FIG. 4  is a magnified view of the cross section through E-E with the protective arm liner in position over and about the arm; 
         FIG. 5  is a perspective view of the arm liner of  FIG. 4 ; 
         FIG. 6  is a further perspective view of the arm liner of  FIG. 5 ; 
         FIG. 7  is the cross sectional view of  FIG. 4  further including indicated relative radial dimensions of both the arm and the protective arm liner according to a specific implementation of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION 
     Referring to  FIG. 1 , a gyratory crusher bottom shell  100  comprises a bottom shell wall  101  extending circumferentially around a central longitudinal axis  115 . Wall  101  comprises an axially uppermost annular end  111  and a lowermost annular end  112 . In particular, an annular rim  102  projects radially outward from wall  101  at upper end  111  to provide a flange for coupling to a topshell frame (not shown). A central hub  107  extends circumferentially around axis  115  and is positioned radially inside shell wall  101  towards the axially lowermost end  112 . Hub  107  is supported and held in position within shell wall  101  via a plurality of support arms  106  that extends radially between a radially outermost region  110  of the hub  107  and a radially inward facing surface  103  of shell wall  101 . 
     Hub  107  comprises a central cavity  114  aligned axially with axis  115  to receive a gyratory crusher main shaft (not shown) and to support the shaft towards its lowermost end for gyroscopic procession within the crusher. Hub  107  comprises an uppermost annular end surface  113  and an annular lowermost end surface  301  (referring to  FIG. 3 ), with end surfaces  113 ,  301  realigned substantially parallel and perpendicular to axis  115 . Upper end surface  113  represents an uppermost part of hub  107  that is positioned generally within an axial lower half of shell  100  between upper and lower ends  111 ,  112 . 
     Shell wall  101  and in particular radially inward facing wall surface  103  defines an internal chamber  104  that represents a discharge region through which material falls having been crushed between the opposed radially outer and inner crusher shells (not shown) positioned generally within the topshell (not shown). So as to protect shell surface  103  from the discharged material, a modular wear resistant liner assembly  108  is secured at inner surface  103  via attachment bolts  116 . The liner assembly  108  further comprises respective support arm liners  105  that have a first component that extends over a region of the shell inner surface  103  and a further component that extends radially over and about each support arm  106 . Arm liners  105  are also secured primarily by a pair of attachment bolts  109  that extend through liner  105  and shell wall  101 . 
       FIGS. 2 and 3  illustrate the bottom shell  100  of  FIG. 1  with one of the support arm liners  105  removed for illustrative purposes. Each support arm  106  comprises an axially uppermost region, represented by an upward facing surface  203 , and an axially lowermost region  204 . The upward facing surface  203  extends radially between shell inner surface  103  and the radially outermost part  110  of hub  107 . Arm surface  203  comprises a radially outer region  201  located at shell inner surface  103  and a radially inner region  202  positioned at the outermost region  110  of hub  107 . A seat  200  is positioned radially between regions  201  and  202  and is formed as a saddle or axially extending depression at the arm surface  203 . Accordingly, seat  200  is positioned axially lower than the annular uppermost end surface  113  of hub  107 . That is, in a direction radially inward from the axially lowermost part of seat  200 , the upward facing arm surface  203  curves axially upward at region  202  to meet hub uppermost surface  113 . In the opposite radial direction from the seat  200 , the uppermost surface  203  slopes axially upward towards radially outermost region  201  to provide a smooth curving transition onto the shell inner surface  103 . Accordingly, a radially outermost region of arm upper surface  203  slopes axially downward from shell inner surface  103  to seat  200  and then curves or slopes axially upward from seat  200  to the uppermost end surface  113  of hub  107 . Each arm  106  comprises an axial thickness or length extending below the axial length of hub  107  defined between uppermost annular end surface  113  and lowermost annular end surface  301 . 
     Referring to  FIG. 4 , each support arm liner  105  comprises a radially outermost region  404  for positioning in contact or near touching contact with shell inner surface  103 . Liner  105  further comprises a radially innermost region  403  for positioning towards hub upper surface  113  and in particular the radially outermost end  110  of upper surface  113 . An axially lowermost surface  402  of liner  105  is positioned opposed to the upward facing arm surface  203  whilst surface  401  of liner  105  is upward facing towards uppermost annular end  111  of shell wall  101 . According to the preferred embodiment, at least a region of upward facing liner surface  401  is aligned substantially perpendicular to axis  115  to be approximately horizontal when the crusher is orientated in normal operational use. This is advantageous to avoid deflecting large volumes of crushed material falling through bottom shell  100  towards central hub  107 . 
     Arm liner  105  comprises a locating foot  400  formed as a stub-projection extending axially downward from downward facing surface  402  and positioned radially towards the radially innermost end  403 . Foot  400  is configured for positioning in contact with arm seat  200  such that liner  105  may be supported exclusively by contact between foot  400  and seat  200 . In particular, seat  200  comprises an axial depth sufficient to accommodate the entire volume of foot  400  and a proportion of a lower region of the liner  105  generally. The curved profile of the arm upper surface  203 , at the region of seat  200  is advantageous to allow liner  105  to be self-seating (by contact with the seat  200 ) such that if the primary attachment bolts  109  fail, liner  105  is maintained in position over and about arm  106 . Additionally, the present configuration is further advantageous in that a radial length of seat  200  is optimised such that a significant volume of the liner  105  is accommodated within the seat (or recess) region to effectively axially lower the mass centre of liner  105  relative to uppermost surface  113 . This is beneficial to prevent the liner  105  from being dislodged from arm  106  by the falling material. 
     Referring to  FIGS. 5 and 6 , each liner  105  comprises a first part  501  for positioning at (and configured to protect) shell inner surface  103 . First part  501  comprises a pair of holes  500  through which the attachment bolts  109  pass to secure liner  105  to surface  103 . A second part  502  of liner  105  is formed as a short tunnel section  504  that projects perpendicular or tangential to first part  501  and is configured for positioning over and about support arm  106  and in particular upper surface  203 . The tunnel part  504  comprises an arched entrance edge and surface  503  and an underside surface  505  positionable opposed to arm surface  203 . Foot  400  projects downwardly from underside surface  505  within tunnel region  504  at a position towards arched edge  503 . The second part  502  is positioned substantially within an axially lower half of liner  105  and extends from a liner lowermost edge  509 . A liner surface  508  is orientated radially inward towards axis  115  and curves axially upward from arched edge  503  towards liner uppermost edge  507  at the first part  501 . A handle  506  projects radially from surface  508  at the uppermost edge  507  to allow convenient mounting and dismounting of liner  105  at support arm  106 . 
     Referring to  FIG. 7 , the present bottom shell assembly is advantageous to distribute the mass of liner  105  between hub  107  and bottom shell wall  101  so as to reduce the tension and likelihood of failure at the primary attachment bolts  109 . This is achieved by specifically configuring the dimensions of the region of seat  200  so as to accommodate and support an axially lowermost part of liner  105  at a region radially towards hub  107 . Distance A corresponds to the radial distance between shell outer surface  300  and the radially outermost region  110  of hub upper surface  113  in a plane  700  aligned coplanar with uppermost surface  113 . Distance B corresponds to the radial distance at plane  700  between the radially outermost region  110  of surface  113  and the region of arm upward facing surface  203  that bisects plane  700 . Distance B therefore corresponds to the radial length of seat  200  that is positioned axially below hub uppermost surface  113 . Distance C represents the radial length of liner  105  between the radially innermost end  403  and radially outermost end  404  (referring to  FIG. 4 ). Distance D corresponds to the radial distance over which liner  105  is accommodated within seat  200  representing the volume of liner  105  that is positioned axially between plane  700  and the axially lowermost part of seat  200 . 
     According to the specific implementation, at plane  700 , the radial length B of seat  200  is substantially 50 to 60% of the radial distance A between the shell wall outer surface  300  and region  110  of hub surface  113 . Additionally, at plane  700 , the radial length B of seat  200  is substantially 70 to 80% of the radial length C of liner  105  between ends  403 ,  404 . Furthermore, at plane  700 , the radial length B of liner  105  occupied within seat  200  is 45 to 55%. 
     An axial depth of seat region  200  relative to hub uppermost surface  113  is optimised to provide both the correct support and seating of liner  105  at arm  106  and to avoid material collecting at the uppermost region of the hub. Accordingly, the axial depth of seat region  200  is such that the upward facing liner surface  401  is positioned axially above hub uppermost surface  113 . The radially innermost liner end  403  is separated by a small radial distance from hub region  110  (at upper surface  113 ) to provide a desired radial clearance between liner  105  and hub  107 . However, according to further embodiments, radially inner liner region  403  may be positioned at or in near touching contact with hub region  110 . 
     Additionally, and according to further embodiments, the shape profile of arm upper surface  203  may comprise planar or angled regions so as to optimise seating of liner  105 . Additionally, liner  105  may be devoid of the downwardly extending foot  400  such that the innermost surface  505  of tunnel region  504  may contact arm surface  203  at seat  200 . Additionally, according to further embodiments, liner  105  may comprise a plurality of feet  400  projecting from surface  505  to contact arm surface  203  at seat  200 .