Abstract:
A mill apparatus ( 1 ) comprises a frame ( 2 ), a mill unit ( 5 ), a mill drive ( 3 ) mounted on the frame ( 2 ) with the mill unit ( 5 ) attached to and suspended from the mill drive ( 3 ). The frame ( 2 ) supports a part of the mill unit ( 5 ) when in a state of disassembly and allows for removal and replacement of a part of the mill unit ( 5 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to mill apparatus, and in particular to such an apparatus facilitating easy servicing. 
       BACKGROUND OF THE INVENTION 
       [0002]    In some milling applications it is necessary to change wearing parts very often, as frequent as every few hours in some applications. 
         [0003]    This is normally a time consuming process which results in the mill being out of operation for a significant period of time. 
         [0004]    It would therefore be desirable to provide an apparatus which provides for easy servicing and the more efficient use of mills. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the invention there is provided a mill apparatus comprising a frame, a mill unit, a mill drive mounted on the frame with the mill unit attached to and suspended from the mill drive. 
         [0006]    Preferably, the frame is adapted to support the mill unit when detached from the mill drive, and advantageously, when lowered with respect to the mill drive. 
         [0007]    The mill unit advantageously includes a housing. Preferably, the housing and the frame include co-operating elements adapted to constrain lateral movement of the mill unit with respect to the frame. The co-operating elements may include a pin and hole for receiving the pin. 
         [0008]    Preferably, the frame provides space between members thereof for the removal of a detached mill unit laterally with respect to the frame. 
         [0009]    According to another aspect of the invention there is provided a method of removing a part of a mill unit comprising the steps of: 
         [0010]    Supporting the mill unit; 
         [0011]    Releasing the mill unit from the mill drive; 
         [0012]    Lowering the mill unit so that it is supported by the frame; 
         [0013]    Releasing a part of the mill unit requiring servicing or replacement; 
         [0014]    Lifting that part of the mill unit and removing it through an opening in the frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    In the Drawings, which illustrate preferred embodiments of the invention: 
           [0016]      FIG. 1   a  is a schematic cross-sectional representation of mill apparatus according to one aspect of the invention; 
           [0017]      FIG. 1   b  is a schematic representation of the mill apparatus shown in  FIG. 1   a  in a partially disassembled state; 
           [0018]      FIG. 1   c  is an exploded view of a part of the mill apparatus shown in  FIGS. 1   a  and  1   b;  and 
           [0019]      FIG. 2  is a schematic representation of a lifting bracket. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]      FIGS. 1   a  to  1   c  illustrate a mill apparatus  1  comprising a frame  2 , a pair of mill drives  3 , a feeder  4  and a pair of mill units  5 . 
         [0021]    The apparatus  1  provides for the easy removal and re-attachment of a mill unit  5  to its respective drive  3 . 
         [0022]    The frame  2  comprises longitudinal upper and lower cross-members  2   a  extending between corner upright members  2   c , lateral cross-members  2   b , longitudinal cross-members  2   d  extending between the lateral cross-members  2   b , and central upright members  2   c ′ extending between upper and lower cross-members  2   a.    
         [0023]    The frame  2  further comprises feet  2   e  located at the corners of the frame on the underside thereof, and pads  2   f  located at the corners of the frame on the underside thereof. 
         [0024]    Each mill unit  5  is attached to a drive housing  3  having brackets  3   a . Each bracket  3   a  mounts a foot  3   b  which sits on the pad  2   f  with an isolation pad  3   c  situated between the foot  3   b  and pad  2   f.    
         [0025]    The mill unit  5  includes a mill housing  5   a  and an end member  5   b . The end member  5   b  includes bores  5   c  which are configured to locate on pins  2   g  mounted on cross-members  2   d . The housing  5   a  includes lifting bracket receiving members  5   d . The lifting brackets  6 , shown in  FIG. 2  comprise a bracket  6   a  configured to receive the fork of a forklift truck for example, a flange  6   b  having holes  6   c  through which bolts may pass to attach the bracket  6  to the lifting bracket receiving member  5   d , and a boss  6   d  for engaging the lifting bracket receiving member  5   d.    
         [0026]    The drive housing  3  includes a rim  3   e  from which extend bolt receiving portions  3   f . As can be seen from  FIG. 1   c , a bolt  3   g  passes through an aperture in the bolt receiving portion  3   f  and into a threaded bore of a bolt receiving portion  5   e  of the mill housing  5   a.    
         [0027]    The mill housing  5   a  also includes bolt receiving portions  5   f , through which bolts  5   g  pass to engage with threaded apertures  5   h  located in end member  5   b.    
         [0028]    Material outlet apparatus  6  includes a bracket  6   a  which attaches to a bracket  5   i  of the end member  5   b.    
         [0029]    To remove one of the mill units  5  from the apparatus  1 , lifting brackets (illustrated in  FIG. 2 ) are attached to the lifting bracket receiving members  5   d . The mill unit  5  is supported through the lifting brackets, for example on the forks of a forklift truck. The bolts  3   g  are removed, which allows the mill unit  5  to be lowered until the end member  5   b  is supported on the cross-members  2   d  of the frame  2  with the pins  2   g  located in bores  5   c.    
         [0030]    With the end member  5   b  securely supported on the frame  2 , bolts  5   g  are removed from threaded apretures  5   h , releasing the housing  5   a  from the end member  5   b . The mill housing  5   a , supported by a lifting means such as a forklift truck may then be removed, and replaced with another mill housing  5   a.    
         [0031]    The apparatus  1  provides for the very straightforward removal and replacement of mill housings  5   a  for servicing and repair. When milling very hard materials, the mill housing  5   a  and the components supported therein may require serving and repair every few hours. Therefore it is desirable to provide for the easy removal and replacement off the mill housing  5   a.    
         [0032]    In the apparatus  1  the mill drive housing  3  is mounted above the mill unit  5 . Not only does this allow for an arrangement wherein the mill housing  5   a  may easily be removed, but also the mill drive components located in the housing  3  are less likely to be infiltrated by dust and other material passing through the mill, because they are located gravitationally above the mill unit  5 . 
         [0033]    Further, by facilitating the support of the mill units  5  on the apparatus when detached from the drive housings  3 , the drive housings  3  may also be removed for servicing and repair. 
         [0034]    Whilst the illustrated example shows a pair of mill units  5 , the apparatus may comprise only one mill unit  5 , or may comprise more than two mill units  5 . 
         [0035]    An outlet  6  extends downwardly from the underside of the mill unit  5 . With the apparatus dismantled, as illustrated in  FIGS. 1   b  and  1   c , the outlet  6  is nevertheless supported above the ground by the frame. 
         [0036]    As can be seen from  FIGS. 1   a  and  1   c , the drive housing  3  includes in feed elements  3   d  to each side of the housing. The outer element  3   d  of each housing  3  is blanked off with a blanking plate  3   d ′. The inner in feed elements  3   d  are each attached to a feeder  4 . The provision of each drive housing with two in feed elements allows multiple products to be introduced to the mill  5 . The feeder  4  may include a plate to block the feeding of material to one of the mill units, for example if one of the mill units  5  is removed for servicing and not immediately replaced, the feeder  4  may be adjusted so that material is fed only to the remaining mill.