Abstract:
A shredder apparatus and method for shredding wet chip materials in which the shredder utilizes a shredder mechanism having a shaft attached to a frame, a bearing assembly disposed on the shaft, and a rotatable rotor disposed on the bearing assembly. First shredder members are attached to and rotatable with the rotor, and cooperate with second shredder members attached to the frame to shred wet chip materials fed into the shredder apparatus.

Description:
[0001]     This application is a divisional of U.S. application Ser. No. 10/611,526, filed on Jul. 1, 2003, which is hereby incorporated herein in its entirety. 
     
    
     FIELD  
       [0002]     The method for shredding and the shredder apparatus disclosed herein relate generally to the shredding of wet chip materials that subsequently are separated into dry chips and fluid; and, more specifically, to an improved shredder apparatus having a rotor shredder mechanism that allows for shredding of bales of stringy wet chip into granular wet chips.  
       BACKGROUND  
       [0003]     Bales or batches of wet chip materials often are generated in the course of machining operations. The wet chip materials include both relatively small wet chips, referred to herein as granular wet chips, and stringy pieces of wet chips. The chips are covered or coated with lubricating, cooling or other fluid. Additionally, undesired solids such as bolts, nuts, etc. sometimes are found in the bales or batches of wet chip material.  
         [0004]     Prior to sending wet chips to a centrifugal separator, where wet chips are separated into dry chips and fluids, such as is illustrated in Nemedi U.S. Pat. No. 5,106,487, the stringy wet chips generally must be shredded into granular wet chips. Otherwise, commercially-available wet chip separation systems sometimes will not function due to the large size of the stringy wet chips. The wet chip material is fed into a shredder apparatus where the stringy wet chips are shredded into granular wet chips that can be more readily transported in the wet chip separation system free from interfering with the wet chip separation process or damaging the wet chip separation equipment.  
         [0005]     Shredder apparatuses for shredding wet chip materials are well known in the art. Often the shredder apparatus utilizes two rotatable shredder shafts each mounted in bearing units disposed in a shredder frame. Shredder members are disposed on each shaft, the rotating shredder members on one shaft cooperating with shredder members on the other shaft to shred wet chip material. Shredder apparatuses that employ a plurality of rotating shafts generally are relatively large, bulky units that, because of their size, are not adaptable to certain applications that have reduced space constraints.  
         [0006]     In other applications, it is known to employ a wet chip shredder apparatus that utilizes a plurality of first shredder members disposed on a single rotatable shaft. A plurality of second shredder members is fixed to the shredder frame. In a shredding operation the first shredder members engage the second shredder members to shred wet chip material. An example of this type shredder is shown and disclosed in the co-pending application Ser. No. 10/100,786, filed by the present inventor on Mar. 19, 2002. While this shredder device is satisfactory for shredding wet chip material, it has been observed that lubricating and flume fluid can migrate to the location of bearing units that house the rotatable shaft. A concern exists that, over time, the fluid could possibly contaminate or otherwise damage one or more of the bearing units.  
         [0007]     Further, it has been found in some applications that relatively heavy objects such as metal bolts, nuts, etc. are located in the bales of wet chip material. In some instances, these heavy objects can cause the shredder to jam. On such occasions, the shredder device must be stopped until the jam is cleared. In other situations, these heavy objects pass through the shredder and travel in the system with the potential for causing damage to a centrifugal wet chip separator or other parts of the wet chip separation system.  
       SUMMARY  
       [0008]     Briefly, a shredder apparatus may have a shredder mechanism that includes a shaft attached to a shredder apparatus frame. A bearing assembly, comprising for example two spaced bearings, is disposed on the shaft and located inwardly from the shaft ends. A rotatable rotor, comprising for example an elongated cylindrical member, may be positioned over the shaft and is disposed on the bearing assembly. The rotor may be of a length such that the rotor extends over the bearing assembly, whereby the bearing assembly is sandwiched between the shaft and rotor. Seal members may be disposed on the shaft and located at the rotor ends serve to preclude lubricating, coolant or other fluid from coming in contact with the bearing assembly.  
         [0009]     Spaced shredder wheels, each having a plurality of spaced shredder arms extending outwardly from the wheel, are attached to and rotatable with the rotor. A plurality of spaced comb members is disposed on, but is not rotatable with, the rotor. The comb members are attached to the shredder assembly frame, whereby, upon rotation of the rotor, a shredder wheel will cooperate with a comb member to shred wet chip materials into granular wet chips.  
         [0010]     In one embodiment, the shredder rotor is rotated in a direction opposite a feed direction of wet chip materials to be shredded. The shredder arms on the shredder wheels contact wet chip materials, e.g., aluminum, steel or other metal chip materials, and lift the wet chip materials upwardly into the shredder. The shredder wheels and comb members then cooperate to shred the wet chip materials into granular wet chips that may be more easily transported through a wet chip separation system to one or more centrifugal separators. During the course of the shredding operation, undesired heavy objects may drop either by gravity or centrifugal force into a removable tray attached to the shredder assembly frame, thereby being separated from the wet chips.  
         [0011]     In a further embodiment, the shredder rotor is rotated in the same direction as the feed direction of the wet chip material to be shredded. The stringy wet chip material will shred at the location of a second shredder arm on the comb member. In the event a heavy, unwanted object contacts the second shredder arm, an increased motor amperage will occur and the motor is signaled to change direction. The unwanted object will then be lifted in the arms of the shredder wheels and ultimately transported to a drop out opening or tray. The motor will then change direction again, and the shredding operation will resume principally at the location of the second shredder arm.  
         [0012]     To minimize potential shredder wheel misalignment problems that sometimes occur with shredder apparatuses, spacers may be disposed between the shredder wheels. By separating the shredder wheels, the possibility of a shredder wheel contacting another shredder wheel due to vertical misalignment is reduced.  
         [0013]     Other advantages of such a shredder apparatus will become apparent from the drawings and the following detailed description of the shredder assembly and method of shredding. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  shows a front perspective view of an exemplary shredder apparatus, and provides a size comparison between the shredder apparatus, a five-gallon container and a one-gallon container;  
         [0015]      FIG. 2  shows a rear perspective view of the shredder apparatus shown in  FIG. 1  with the dropout tray removed from its normal position on the shredder frame;  
         [0016]      FIG. 3  shows a plan view of the shredder apparatus shown in  FIG. 1 ;  
         [0017]      FIG. 4  shows a right side view of the shredder apparatus shown in  FIG. 1 ;  
         [0018]      FIG. 5  shows a left side view of the shredder apparatus shown in  FIG. 1  with a portion of the shredder frame removed;  
         [0019]      FIG. 6  shows a rear view of the shredder apparatus shown in  FIG. 1  with a portion of the shredder frame removed;  
         [0020]      FIG. 7  shows a section view taken along line  7 - 7  in  FIG. 4 ;  
         [0021]      FIG. 8  shows a side view of a shredder comb member employed in the embodiment illustrated in  FIGS. 1-7 ;  
         [0022]      FIG. 9  shows a left side view of a further embodiment of a shredder apparatus in which the comb members include first and second spaced arms, with a portion of the shredder frame removed;  
         [0023]      FIG. 10  shows a side view of a shredder comb member employed in the embodiment illustrated in  FIG. 9 ; and,  
         [0024]      FIG. 11  shows a schematic block diagram of the drive assembly and controller assembly employed in the embodiment illustrated in  FIG. 9 . 
     
    
     DETAILED DESCRIPTION  
       [0025]     An exemplary shredder apparatus  10  comprises housing assembly  11  that, as illustrated in  FIGS. 4, 5  and  7 , includes base  12 , front wall  13 , back or rear wall  14  and side walls  15 ,  16 . Open top plate  17  is fixed at top plate ends  18 ,  19  and top plate sides  20 ,  21  to the appropriate housing front, back and side walls.  
         [0026]     Motor mount wall  22  extends upward from base  12  ( FIG. 7 ). Wall  22  is substantially parallel to and spaced from sidewall  16 . Top wall  23 , which can be made of either a rigid or flexible material, is removably attached to walls  16 ,  22 .  
         [0027]     As illustrated in  FIG. 7 , drive assembly  30  includes motor  31  having a shaft  32  with a bushing  32   a  keyed to the shaft. Screws  33 ,  34  extend through openings in motor flange  35  and openings  36 ,  37  in wall  22 . The screws thread into tapped holes  38 ,  39  in motor mounting plate  39   a , which abuts wall  22 . It has been found that a 460 Volt, three phase, 60 Hz electric motor may be employed. It is appreciated that other size motors could be utilized by one of ordinary skill in the art.  
         [0028]     Positioned below motor  31  is fixed shaft  40  which is greater in length than the distance between spaced sidewalls  15 ,  16 . Elongated shaft  40  is tapered for a portion at each shaft end  41 ,  42 . Taper  43  extends inwardly for a discrete distance from each shaft end. Taper  43  comprises a first tier  44  and a second tier  45 .  
         [0029]     A bearing assembly comprising spaced bearings  50 ,  51  is seated on shaft  40 , each bearing being located on a tapered portion of shaft  40 . In this particular embodiment illustrated in the drawings, bearings  50 ,  51  seat on shaft taper tier  45 .  
         [0030]     Cylindrical rotor  52  having an outer surface  53  and inner surface  54  is positioned over fixed shaft  40 . Rotor  52  is recessed at each rotor end  55 ,  56  as illustrated, for example, in  FIG. 7 . Each bearing is positioned so that it is sandwiched between shaft  40  and rotor  52 . Bearing  50  is disposed within a rotor recess at rotor end  55  while bearing  51  is disposed within a rotor recess at rotor end  56 . A first seal member  57  is disposed on shaft surface  45  at rotor end  56 . A second seal member  58  is located on shaft surface  45  at rotor end  55 . The seal member may be made of any conventional sealing material such as polyvinyl chloride (PVC) or Buna N, so long as the material aids in providing a seal at the location of the rotor ends.  
         [0031]     Faceplate  60  is bolted at  62  to sidewall  16 , while faceplate  63  is bolted at  64  to sidewall  15 . Shaft end  41  extends through an opening in faceplate  60 , and shaft end  42  extends through an opening in faceplate  63 . Faceplate  60  is located adjacent seal member  57 , and faceplate  63  is positioned adjacent seal member  58 .  
         [0032]     Lock member  65  is disposed on shaft  40  at shaft end  41  and seats against faceplate  60 . Lock member  66  is disposed on shaft  40  at shaft end  42  and seats against faceplate  63 . Each lock member is illustrated as being welded at  68  to a respective faceplate. If desired, other shaft locking arrangements, for example, a two piece clamp trough, could be employed. Similarly, the shaft ends could be threaded and lock nuts could be utilized in place of the locking arrangement shown in the drawings. With the particular arrangement shown in the drawings, bearings  50  and  51  are placed in a relatively closed or sealed location formed by shaft  40 , rotor  52  and seal members  57 ,  58 .  
         [0033]     A first sprocket  70  is keyed at  71  to motor shaft  32  at the location of bushing  32   a  ( FIG. 7 ). A second sprocket  72  is bolted at  73  to sprocket mounting plate  74 , the latter being welded at  75  to rotor  52  at outer rotor surface  53 . A drive chain, not shown, connects sprockets  70 ,  72  whereupon activation of motor  31  and the sprocket chain assembly, rotor  52  rotates on bearings  50 ,  51 . Shaft  40  is fixed in place and does not rotate. Referring to  FIG. 7 , drive assembly  30  includes motor  31  and the sprocket chain assembly, the latter being enclosed by walls  16 ,  22  and  23 .  
         [0034]     A plurality of spaced shredder wheels  80 , each wheel including spaced shredder arms  81  extending outwardly from the wheel, is keyed at different locations  82  to rotor  52 . A plurality of spaced shredder comb members  84 , illustrated, for example, in  FIGS. 5 and 8 , is located on rotor  52 , and is positioned so that a comb member  84  is adjacent a shredder wheel  80 .  
         [0035]     With reference to  FIG. 8 , each comb member  84  includes a comb portion  85  and a comb arm  86 . Opening  87  is formed in comb portion  85 , while a key slot  88  is formed at the outboard end of comb arm  86 . Each comb member is adapted to be inserted on rotor  52 , and seats on the rotor at the location of comb opening  87 ; however, the comb members do not rotate with rotor  52 . End comb member is keyed at the location of slot  88  to key bracket  89 , the later being fixed to rear wall  14 , as seen in  FIG. 5 . Accordingly, shredder wheels  80  rotate relative to fixed adjacent comb members  84  and together, the shredder wheels and comb members cooperate to shred or otherwise cut wet chip material passing through shredder apparatus  10 .  
         [0036]     Spacers, in the form of washer-like members  90 , are disposed on rotor  52  and positioned between adjacent comb members  84 , as shown in  FIG. 7 . The spacers  90  serve to space the shredder wheels  80  apart so that, should any vertical misalignment of a shredder wheel  80  occur, the spacer  90  will preclude contact with another shredder wheel  80 .  
         [0037]     Compression spring assembly  92  formed of compression spring  93  and spring plate  94  is positioned against the outboard surface of comb member  84  located near one end  56  of rotor  52 . Compression spring assembly  96  formed of compression spring  97  and spring plate  98  is positioned against the outboard surface of comb member  84  near the opposite rotor end  55 .  
         [0038]     A heavy object dropout tray or box  100  is removably attached to the outer surface of rear wall  14  in a manner well known to a person of ordinary skill in the art.  
         [0039]     In operation, wet chip materials to be shredded comprising granular wet chips, stringy wet chips, unwanted solids (such as bolts, nuts, etc.) and lubricating, cooling, flume or other fluid are delivered to the opening  101  in the front wall  13  of shredder  10 . The wet chip material moves into the shredder traveling in the direction shown by arrow “A” ( FIG. 4 ). Upon actuation of drive assembly  30 , rotor  52  rotates and travels in a direction, shown by arrow “B,” opposite to the direction of wet chip material travel. As the wet chip material passes into shredder  10 , shredder arms  81  on shredder wheels  80  engage the material and cause at least the stringy wet chip material to be lifted upwardly in the direction of arrow “B” toward a shredding station.  
         [0040]     At the shredding station, shredder wheels  80  and shredder comb members  84  engage and cooperate to shred the stringy wet chip material and reduce it to granular wet chips. As rotor  52  continues to rotate, shredded granular wet chips drop to the bottom of shredder  10 . Unwanted solids in the form of nuts, bolts and the like which may have been lodged or otherwise entrained in the stringy wet chip material to be shredded either drop out of the material or are thrown by centrifugal force into collection tray  100 . The shredded wet chips now reduced to a desired size then can be processed out of shredder apparatus  10  at the opening  102  in rear wall  14  in a centrifugal separation system whereby the wet chips are separated into dry chips and fluid.  
         [0041]     Shredder apparatus  10  can be made of a reduced size such as illustrated in  FIG. 1 , where shredder apparatus  10  is shown compared in size to a five-gallon container and a one-gallon container. One particular shredder apparatus  10 , for example, has a width of 16¼inches, a depth of 19 inches, and a height of 26 inches. A reduced-size shredder apparatus is particularly desirable in those applications where there is a space constraint.  
         [0042]     Additionally, the use of spacer washers  90  serve to minimize shredder wheel alignment problems because the shredder wheels  80  have been spaced a satisfactory distance from one another.  
         [0043]     A further embodiment of a shredder apparatus  10  is illustrated in  FIGS. 9-11 . In this particular embodiment, comb members  103  replace comb members  84 . Each comb member  103  includes base portion  104 , and a first arm  105  and a second, spaced arm  106  extending outwardly from base portion  104 .  
         [0044]     An opening  107  is formed in base portion  104 , while a key slot  108  is formed at the outboard end of comb arm  105 . Comb arm  106  preferably is serrated at  109  along substantially the length of one side  110  of comb arm  106 .  
         [0045]     Each comb member  103  is adapted to be inserted on rotor  52  and seats on the rotor  52  at the location of comb opening  107 ; however, comb members  103  do not rotate with rotor  52 . Each comb member  103  is keyed at the location of slot  108  to key bracket  89 , the later being fixed to rear wall  14 , as seen in  FIG. 9 .  
         [0046]     In addition to replacing the comb members  84  with the comb members  103 , shredder wheels  80  are replaced with shredder wheels  116 . Wheels  116  each include spaced shredder arms  118  extending outwardly from the center of wheel  116 . Each shredder arm  118  has sides  120 ,  121  formed or grooved inwardly at  122  to define a concave surface, as illustrated in  FIG. 9 . Accordingly, in this embodiment, shredder wheels  116  rotate relative to fixed adjacent comb members  103 , and together the shredder wheels  116  and comb members  103  cooperate to shred or cut wet chip materials at the locations of comb arms  105  and  106 .  
         [0047]     In particular, during the operation of the embodiment of the shredder apparatus  10  of  FIG. 9 , wet chip materials to be shredded, comprising granular wet chips, stringy wet chips, unwanted solids (such as bolts, nuts, etc.), and lubricating, cooling, flume or other fluid, are delivered to the opening  101  in the front wall  13  of shredder apparatus  10 . The wet chip material moves into the shredder apparatus  10  traveling in the direction shown by the arrow “D” in  FIG. 9 .  
         [0048]     Upon actuation of drive assembly  30 , rotor  52  rotates and travels in a direction, represented by an arrow “E” in  FIG. 9 , that is the same direction as the direction of the wet chip material travel. As the wet chip material passes into shredder  10 , shredder arms  118  engage the wet chip materials and direct at least the stringy wet chips toward a shredding station disposed at comb arm  106 . Comb arms  106  and shredder arms  118  cooperate to shred the stringy wet chips.  
         [0049]     In the event that a heavy, unwanted solid enters shredder apparatus  10 , the solid travels to the shredder station disposed at the comb arm  106 . Inasmuch as the shredder apparatus  10  cannot shred the unwanted solid, an increase in the motor amperage occurs, whereupon the motor  31  stops and changes direction of rotation. With the change in the direction of rotation of the motor  31  (and in particular motor shaft  32 ), rotor  52  will change its direction of rotation, and the shredder wheels  116 , fixed to the rotor  52 , will the rotate in the direction indicated by arrow “F” in  FIG. 9 . As the shredder wheels  116  rotate in the direction of arrow “F”, the unwanted solid will be carried on one or more surfaces  122  on the shredder arm  118 , and transported in the direction of arrow “F”. The unwanted solid may be transported in somewhat of a circular direction until the unwanted solid, for example, drops onto the top of first comb arm  105  and passes therealong into drop out tray  100 . After rotor  52  travels in the direction of arrow “F” for a period of time, for example, until at least the unwanted solid passes into tray  100 , the motor  31  again changes direction and rotor  52  travels in the direction of arrow “E”, whereupon shredding of the wet chip material resumes.  
         [0050]      FIG. 11  illustrates a controller system  128  associated with the embodiment of the shredder apparatus  10  in  FIG. 9 . The controller system  128  includes a controller  130 . When controller  130  is turned to an “on” position, the controller  130  closes forward switch  131  and actuates motor  31 , which causes motor shaft  32  to rotate in the direction of arrow “E”.  
         [0051]     Upon contact of an unwanted solid with comb arm  106 , increased amperage occurs in motor  31  and is sensed by sensor  132 . The controller  130  receives signals from the sensor  132  representative of the increased amperage, and, in response, turns off motor  31  and opens forward switch  131  to a disconnect position. Following a dwell period of, for example, approximately one second, the controller  130  closes reverse switch  133  and actuates motor  31 , causing motor shaft  32  to rotate in the direction of arrow “F”.  
         [0052]     Following a time period during which an unwanted solid is transported to the top of comb arm  105 , the controller  130  turns off motor  31  and opens reverse switch  133 . Following a dwell period of, for example, approximately one second, the controller closes forward switch  131  and actuates motor  31 , whereupon motor shaft  32  again rotates in the direction of arrow “E” and shredding occurs at the location of shredder arm  106 .  
         [0053]     It is appreciated that while one system  128  for actuating motor  31  to permit shaft rotation in the direction of arrows “E” and “F” has been shown, other systems for rotating motor shaft  32  in the desired directions would be apparent to one of ordinary skill in the art. For example, rather than using the controller  130  to control the motor  31  to make motor shaft  32  rotate in a particular direction for a particular amount of time, the controller may control the motor  31  to make the motor shaft rotate in a particular direction for a particular number of revolutions or over a particular angular distance.  
         [0054]     While the bales of stringy wet chips are shredded principally at the shredder stations at the second comb arms  106  in the embodiment of  FIGS. 9-11 , shredding can also occur at the location of the first comb arms  105  during the course of the unwanted solid removal.  
         [0055]     Similarly, while comb arm  106  has been shown to have a serrated shredding or cutting surface  109  along side  110 , it may be that, in some applications, serrations are not required. Accordingly, a person of ordinary skill in the art could select other shapes for the sides  110 , for example, a smooth surface.  
         [0056]     While the shredder apparatus  10  has been shown standing alone, it is appreciated the shredder apparatus  10  could be employed in a flume, where bales of stringy wet chip material, granular wet chips and unwanted solids are transported in a fluid to the shredder apparatus  10 . Shredder wheels  80 , each with its respective shredder arms  81 , would engage and lift the stringy wet chip material upward, at least partially out of the flume, and then shred the material. An example of the use of a shredder apparatus employed in a flume application is shown and disclosed in the co-pending application Ser. No. 10/100,876, filed by the present inventor on Mar. 19, 2002, the disclosure and claims of which are incorporated herein by reference.  
         [0057]     While one or more embodiments have been illustrated and described in detail herein, it will be understood that modifications and variations thereof may be effected without departing from the spirit of the invention and the appended claims.