Abstract:
A retaining wedge assembly for securing an impeller bar to the rotor of a horizontal shaft impact crusher comprises a recess defined in the rotor and sized to receive the impeller bar. The recess includes a first seat shaped to engage a first portion of the impeller bar and a second seat. A retaining wedge includes a first portion adapted to engage a second portion of the impeller bar, and a second portion sized to engage the second seat. A countersunk slot on the second seat receives the retaining wedge, which in turn cooperates to secure the impeller bar in the recess. Guide flanges may be provided for limiting axial movement of the retaining wedge. Thus, the impeller bar may be supported in the recess prior to start-up of the horizontal shaft impact crusher.

Description:
RELATED APPLICATIONS 
     This application claims priority from U.S. Provisional Application Ser. No. 60/347,198, filed Jan. 9, 2002. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to impact crushers, and, more particularly, to an apparatus for securing an impeller bar to the rotor of a horizontal shaft impact crusher. 
     BACKGROUND OF THE INVENTION 
     Horizontal shaft impact crushers are commonly employed to pulverize many different types of materials including, by way of example rather than limitation, asphalt, concrete, and rock. Such crushers typically include a frame, a crushing cavity, and a rotor disposed within the cavity and supporting a number of impeller bars. Typically, the rotor includes a plurality of discs that are axially spaced relative to the rotational axis of the rotor, with each of the discs having a number of recesses in which the impeller bars are mounted. The rotor is typically driven by an external drive mechanism. 
     The rotor and the attached impeller bars are generally surrounded by a number of breaker plates. The frame includes a feed opening to permit the material to be fed into the crushing cavity, such that the material comes into contact with the impeller bars of the rotating rotor. The impeller bars repeatedly throw the material against the breaker plate(s), thereby breaking the material into smaller pieces. 
     As is known, the impeller bars must be adjusted periodically to account for wear. Eventually, the impeller bars must be replaced altogether. Thus, there must a mechanism to provide for the easy adjustment and/or the eventual removal of the impeller bars from the rotor. 
     Many impeller bars are secured to the rotor using a wedge assembly that secures the impeller bars within the recess. The wedge is typically oriented such that the tendency of the impeller bar to slide radially away from the axis of the rotor is resisted by the wedge bearing against a portion of the recess. The wedge and the recess are shaped such that the gripping forces of the wedge(s) against the impeller bar actually increase as the impeller bar slides moves (e.g., slides radially outwardly). Thus, the impeller bar(s) actually gets tighter after the crusher has been started. 
     However, the impeller bars and the wedges might not be fully secured until after start up of the crusher. Thus, it is desirable to ensure that the wedges and impeller bars are at least temporarily secured prior to start up of the crusher. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic elevational view of a horizontal shaft impact crusher; 
         FIG. 2  is a schematic illustration of a rotor assembly for use on the horizontal shaft impact crusher and having the three impeller bars secured by a retaining wedge assembly constructed in accordance with the teachings of the present invention; 
         FIG. 3  is a perspective view of the rotor; 
         FIG. 4  is an enlarged fragmentary elevational view of the retaining wedge assembly in accordance with the teachings of the present invention; 
         FIG. 5  is an enlarged fragmentary exploded view thereof; 
         FIG. 6  is an enlarged fragmentary view in perspective of a seat for supporting the wedge and having a counterbored slot; 
         FIG. 7  is an enlarged fragmentary view in perspective of a wedge for mating with the seat of  FIG. 6 ; and 
         FIG. 8  is an enlarged fragmentary elevational view taken at the circumscribed area of FIG.  1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The embodiment(s) described herein are not intended to be exhaustive or to limit the scope of the invention to the precise form or forms disclosed. The following embodiment(s) have been chosen and described in order to best explain the principles of the invention and to enable others skilled in the art to follow its teachings. 
     Referring now to the drawings,  FIG. 1  illustrates a horizontal shaft impact crusher  10  having a frame  12  and a housing  14  enclosing an internal crushing cavity  16 . A rotor  18  is supported on bearings (not shown) such that the rotor  18  rotates about a central axis  20  in a direction generally indicated by the reference arrow A. The rotor  18  includes a plurality of hammers or impeller bars  22 ,  24  and  26 . The impeller bars  22 ,  24 ,  26  may be of conventional construction. Each of the impeller bars  22 ,  24 ,  26  are disposed generally adjacent an outer periphery  28  of the rotor  18 . The housing  14  is provided with a feed opening  30 , which permits aggregate material (not shown) to be fed into the cavity  16  in a suitable manner as would be known. 
     As is known, the aggregate material entering the crushing cavity  16  through the feed opening  30  comes into contact with the impeller bars  22 ,  24 ,  26 , such that the impeller bars strike the aggregate material and propel the aggregate material toward one or more breaker plates  32 . The aggregate material is thus crushed into smaller sizes in response to striking the breaker plates  32 . As would be known, a conventional drive mechanism (not shown) and a gear train (not shown) are operatively coupled to the rotor  18  in order to rotate the rotor  18  about its central axis  20 . 
     Referring now to  FIGS. 2 and 3 , the rotor  18  is typically constructed from a plurality of discs  34 , with four such discs  34  being shown in FIG.  3 . Typically, the discs  34  are spaced apart along the central axis  20  of the rotor  18 . It will be understood that additional or fewer discs  34  may be employed. It will also be understood that the rotor  18  may be constructed using any other suitable construction. 
     Each disc  34  will preferably have a plurality of recesses  36 , with the recesses  36  being spaced about the periphery  28  of the rotor  18 . In the rotor  18  shown in  FIG. 2 , each disc  34  includes three such recesses  36 , with the recesses spaced apart generally equal distances about the periphery of the rotor  18 , such that the rotor  18  accommodates the three impeller bars  22 ,  24 ,  26 . Additional or fewer recesses  36  may be provided, in order to accommodate additional or fewer impeller bars as would be known in the art. It will be understood that only a single one of the impeller bars  22  disposed in a corresponding one of the recesses  36  will be described herein in detail. The remaining impeller bars  24 ,  26  may be suitably secured in their corresponding recesses  36  as required in a similar manner. 
     As shown in each of  FIGS. 2 and 3 , each recess  36  includes a seat  38  (to the right of the impeller bar  22  when viewing the Figs.) and a seat  40  (to the left of the impeller bar  22  when viewing the Figs.). The seat  38  may include a backer bar  41  ( FIGS. 1 ,  2 ,  3  and  8 ). The backer bar  41  will preferably be constructed of a material that is softer than the disc  34 , such that the backer bar  41  (which may be removable or which may be welded in place), will wear faster than the seat  38 , thus extending the service life of the seat  38  and hence the disc  34 . Alternatively, the backer bar  41  may be eliminated. For the sake of brevity, the following discussion will treat the seat  38  as if the seat  38  is defined on the disc  34 . 
     The impeller bar  22  includes a radially outer portion  44 , a radially inner portion  46 , and a pair of opposed faces  48 ,  50 . A retaining assembly generally designated as  52  ( FIG. 2 ) assembled in accordance with the teachings of the present invention is provided. In the disclosed example, the retaining assembly  52  includes a wedge  54 . Alternatively, the retaining assembly  52  could include another suitable shape that is arranged to interact with the shape of the recess  36  and the seats  38 ,  40  to apply a suitable force to the impeller bar  22 . 
     Referring now to  FIG. 8 , the backer bar  41  preferably includes an insert  42 . The insert  42  is sized and shaped to engage a notch  43  on the face  48  of the impeller bar  22 . The insert  42  functions as a key, and may be permanently secured to a seat  45  in the backer bar  41  or, as an alternative, the insert  42  may be removable. 
     In accordance with the disclosed example, the wedge  54  is disposed between the seat  40  and the face  50  of the impeller bar  22 , while the face  48  of the impeller bar  22  abuts a face  56  of the backer bar  41 . Alternatively, it will be understood that the wedge  54  may be positioned on the opposite side of the impeller bar  22  so as to contact the face  48 . In such an alternate form, the seat  40  would preferably include a suitable insert for the purposes described above. 
     Referring now to  FIGS. 4 and 5 , the wedge  54  includes a pair of faces  58 ,  60 . It will be noted that in accordance with the disclosed embodiment, the seat  40  includes an angled face  62  which is oriented at an angle relative to the face  50  of the impeller bar  22 . The face  58  of the wedge  54  is angled with respect to the face  60 , such that the face  58  may be positioned to mate with/abut the angled face  62 , with the face  60  of the wedge  54  oriented parallel to the face  50  of the impeller bar  22 . Preferably, the face  50  of the impeller bar  22  and the face  60  of the wedge  54  may be oriented parallel to the line B extending radially outward from the central axis  20 . An attachment bolt  64  is provided to secure the wedge  54  to the seat  40  in a manner to be described in greater detail below. 
     Referring now to  FIG. 6 , an enlarged fragmentary view in perspective of the seat  40  is shown therein. The seat  40  includes an upper end  66  and a lower end  68 . For ease of reference, the terms “upper” and “lower” refer to the device when oriented as shown in  FIGS. 4-7 . It will be understood that the term “upper” relates to a radially outward direction relative to the central axis  20  of the rotor  18 , while the term “lower” refers to a radially inward direction relative to the central axis  20 . 
     A slot  70  extends between the upper and lower ends  66 ,  68 , such that the angled face  62  of the seat  40  is divided into a pair of surfaces  72   a  and  72   b . In the example shown the surfaces  72   a  and  72   b  are separated by the slot  70 . The upper end  66  of the seat  40  is provided with a counterbore  74 . The counterbore  74  is sized to receive an outer end  64   a  ( FIG. 5 ) of the attachment bolt  64  (e.g., the counterbore  74  is sized to receive all or a portion of a head  75  shown in  FIG. 5  at the outer end  64   a  of the attachment bolt  64 ). The bolt head  75  may thus be substantially protected from undue wear by virtue of being substantially unexposed to excessive direct contact with the aggregate material being crushed. 
     Referring now to  FIG. 7 , the wedge  54  includes a top  76 , a bottom  78 . In the preferred example, the wedge  54  includes a pair of side flanges  80 ,  82 . Alternatively, the side flanges  80 ,  82  may be omitted. The bottom  78  may include a bottom flange  83 . The wedge  54  also includes an aperture  84  that is sized to receive a shaft of the attachment bolt  64 , such that an inner end  64   b  ( FIGS. 4 and 5 ) and of the attachment bolt may extend below the bottom  78  of the wedge  54 . In the disclosed embodiment, the aperture  84  extends through the angled face  58 , as well as through a portion of the bottom flange  83 . 
     Referring again to  FIG. 5 , the wedge  54  may be attached to the seat  40  using the attachment bolt  64  oriented as shown. Preferably, a pair of washers  86 ,  88  are provided, with the washer  86  sized to be received in the counterbore  74 , and with the washer  88  sized to abut the bottom  78  of the wedge  54  such that a threaded nut  90  threaded onto the threaded shaft of the attachment bolt  64  bears against the washer  88 , thus applying a force to the bottom  70  of the wedge  54 . 
     In operation, the impeller bar  22  is attached to the rotor  18  by placing the impeller bar  22  in the recess  36  of the disc  34  (and through an aligned recess in the next adjacent disc or discs), such that the impeller bar extends generally parallel to the central axis  20  of the rotor  18 . As would be known, the face  48  of the impeller bar  22  is seated against or abuts the seat  38  (e.g., the face  48  of the impeller bar abuts the face  56  of the insert  42  should the seat  38  be provided with such an insert). 
     The retaining assembly  52  may be assembled by positioning the attachment bolt  64  substantially as shown in  FIG. 5 , and positioning the inner end  64   b  of the attachment bolt  64  through the slot  70  of the seat  40 . The shaft of the attachment bolt  64  will extend through the aperture  84  in the angled face  58  of the wedge  54 . Again, suitable washers and or lock washers may be provided as desired. 
     Referring now to  FIG. 4 , as the threaded nut  90  is threaded onto the attachment bolt  64 , the wedge  54  will be shifted in a radially outward direction (upward when viewing FIG.  4 ). By virtue of the angle on the seat  40  and the angled face  60  of the wedge  54 , as the attachment bolt  64  is tightened, such as by tightening the threaded nut  90 , the wedge  54  will be urged radially outward and generally toward the right when viewing FIG.  4 . Thus, the face  58  of the wedge  54  will apply a progressively greater force against the face  50  of the impeller bar  22  (e.g., the angled faces  60  and  62 , effectively cause the recess  36  to narrow with distance away from the central axis  20  of the rotor  18 ). Stated another away, the seats  38 ,  40  are separated by a first distance when measured generally adjacent to a lower portion of the recess  36 , and the seats  38 ,  40  are separated be a second and lesser distance when measured generally adjacent to an upper portion of the recess  36 . As also shown in  FIG. 4 , the bottom flange  83  on the wedge  54  may be sized to abut a ledge  85  at the lower end  68  of the seat  40 . 
     Referring now to  FIGS. 6 and 7 , the side flanges  80 ,  82  of the wedge  54  are sized to abut corresponding side edges  92 ,  94  ( FIG. 6 ) of the seat  40 . In the disclosed example the side edges  92 ,  94  are defined at least in part by corresponding side edge portions of the disc  34 . Consequently, should the impeller bar  22  or the wedge  54  drift in a direction generally parallel to the central axis  20  of the rotor  18  (such drift being generally referred to throughout as “axial drift”), the side flanges  80 ,  82  will prevent the wedge  54  from moving past the seat  40 . In the disclosed example, the side flanges  80 ,  82  will permit some limited axial drift, subject to the distance between the side flanges  80 ,  82  minus the distance between the side edges  92 ,  94 . 
     As alternatives, the seat  40  and/or the wedge  78  may be provided with a suitably sized bore or a slot. The bore or slot preferably is suitably sized to permit movement of the wedge  54  in the outward direction and/or in the direction toward and away from the appropriate face of the impeller bar  22 . 
     During operation of the horizontal shaft impact crusher  10 , the impeller bars  22 ,  24 ,  26  will tend to migrate radially outwardly, especially immediately after installation. By virtue of the retaining assembly  52  including the wedge  54 , this outward migration tends to increase the grip of the wedge  54  on the impeller bars. In at least one possible mode of operation, the impeller bars  22 ,  24 ,  26  and the wedges  54  need not be fully tightened prior to start up of the crusher  10 . Instead, operation of the crusher  10  effectively secures the impeller bars by letting the impeller bars tighten themselves. 
     The retaining assembly  52  according to the disclosed example permits the operator of the crusher  10  to apply a preload to the joint between the wedge  54  and the appropriate impeller bar  22 ,  24  or  26 . However, it is known that the impeller bars are subject to axial drift, which, even if contained by the rotor itself, may cause a mis-alignment of the wedges  54 . It therefore is desirable to minimize and/or eliminate axial drift of the wedges  54 . One manner of accomplishing this goal is to provide for the application of a preload to the wedge joint. However, it may be desirable to provide for the application of a preload without developing moments on the wedge, as a moment on the wedge  54  may hinder the application of the preload force. A retaining assembly constructed according to the disclosed example situates the attachment bolt  64  such that the attachment bolt  64  passes through or near to the plane separating the face  50  of the impeller bar  22  and the face  58  of the wedge  54 . This orientation helps to reduce and/or eliminate moments applied to the wedge  54  when applying the preload. 
     Preferably, the wedge  54  is constructed of a material that is softer (i.e., has a lower hardness) than the material that forms the impeller bars  22 ,  24 ,  26  and the disc  34 . Consequently, the wedge  54  is the component that will receive the most abuse. This is desirable in that the wedge  54  is easily replaceable, and can be replaced without disassembly of the rotor  18  and without removal of the impeller bars. 
     Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved.