Abstract:
A shredder, crusher, hammermill, ringmill or the like is provided with a multi-sided rotor shaft to which spider arms and hammers are mounted. The rotor shaft has at least one pair, and preferably two or more pairs, of opposing sides. The hammers are pivotally mounted between supports in the shape of spiders or discs. The supports include openings which have straight sides corresponding to the number of straight sides on the rotor shaft. The straight sides of the support openings engage the rotor shaft straight sides. Hence, the supports are rotationally fixed in place relative to the rotor shaft without the use of keys and keyways, pins, bolts, or other types of fasteners, allowing for easier assembly and reduced maintenance costs for the crusher.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of application Ser. No. 10/120,709 entitled Multi-Sided Shaft For A Crusher filed Apr. 11, 2002, U.S. Pat. No. 6,729,566 which in turn, claims benefit of provisional application Ser. No. 60/284,096 filed Apr. 17, 2001. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable. 
   BACKGROUND OF THE INVENTION 
   This invention relates to crushers, such as shredders, hammermills and ringmills used to process ferrous and non-ferrous scrap material, and, in particular, to an improved rotor shaft for use with the crusher/shredder. 
   Crushers, shredders, hammermills, ringmills, and the like, are often used to process scrap material and stone, to crush or reduce the size of the material so that it can more easily be handled by other equipment for further processing or use. 
   Such crushers typically include a plurality of hammers or rings mounted about a rotatable shaft. As the shaft rotates, the hammers or rings engage and crush whatever media is introduced into the crusher. The hammers or rings can be mounted between supports in the form of spiders or center discs which are positionally fixed relative to the rotor shaft. Typically, the rotor shaft is cylindrical. The use of a cylindrical shaft requires that the supports be positively keyed to the shaft, for example, using a square or rectangular key on the support and a corresponding keyway on the shaft, so that the support cannot rotate relative to the shaft. The use of a keyway weakens the main shaft and makes removal of the supports and end discs a much more difficult task. Further, the key will weaken over time, and eventually the rotor assembly will shift between the shredder housings. Obviously, this can necessitate a repair of the crusher/shredder, requiring that operation of the crusher/shredder be stopped for the duration of the repair. Depending on the location of the support which is no longer positively fixed with respect to the shaft, the crusher/shredder can be shut down for a considerable period of time. 
   BRIEF SUMMARY OF THE INVENTION 
   A shredder, crusher, hammermill, ringmill or the like is provided with a multi-sided rotor shaft to which spider arms and hammers are mounted. The rotor shaft has at least at least one pair, and preferably two or more pairs, of opposing sides. The hammers or rings are pivotally mounted between supports, which take the form of spider arms and center discs. The supports have central openings which have straight sides corresponding to the number of straight sides on the rotor shaft. The straight sides engage the rotor shaft straight sides. Hence, the supports are rotationally fixed in place relative to the rotor shaft without the use of a central key, or other types of fasteners, allowing for easier assembly and reduced maintenance costs for the shredder/shredder. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a cross-sectional view of a crusher having a shaft of the present invention taken along line  1 — 1  of  FIG. 2 ; 
       FIG. 2  is a cross-sectional view of the crusher taken along line  2 — 2  of  FIG. 1 ; 
       FIG. 3  is a side elevational view of the shaft; 
       FIG. 4  is a cross-sectional view of the shaft taken along line  4 — 4  of  FIG. 3 ; 
       FIG. 5  is a plan view of a support in the form of a spider which is mounted on the shaft to support hammers in the crusher/shredder; 
       FIG. 6  is a side elevational view of an alternate embodiment of the shaft; 
       FIG. 7  is a cross-sectional view of the shaft taken along line  7 — 7  of  FIG. 6 ; 
       FIG. 8  is a plan view of a support in the form of a center disc which is mountable on the shaft to support hammers in the crusher/shredder; and 
       FIG. 9  is a cross sectional view of the crusher modified with respect to the use of the draw bar holds to secure the rotors in place. 
   

   Corresponding reference numerals will be used throughout the several figures of the drawings. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The following detailed description illustrates the invention by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the invention, and describes what I presently believe is the best mode of carrying out the invention. 
   A crusher  10  is shown generally in  FIGS. 1 and 2 . The crusher  10  includes a housing  12  having a front wall  14 , a back wall  16 , side walls  18  and  20 , and a top  22 . A feed inlet  24  is formed in the front wall. The feed inlet  24  can extend only a portion of the side-to-side width of the crusher  10 , or can extend substantially the full side-to-side width of the crusher  10 . 
   A rotor or shaft  30  extends between the side walls  18  and  20  to rotate within the housing. As seen in  FIGS. 3 and 4 , the rotor  30  includes a multi-sided central section  32  and two cylindrical end sections  34  extending from opposite sides of the central section. The central section  32  has eight sides, however, it could be formed with fewer sides or more sides, as desired. The central section  32  as shown in  FIG. 4  includes four long sides  36  which are angled generally 90° to each other and four short sides  38  positioned between the long sides  36 , and which are also angled generally 90° to each other. The short sides  38  are curved and define arcs of a circle. Thus, in cross-section, the rotor central section  32  can be defined as a circle which is flattened along four sides to form the long sides  36 . Alternatively, the central section  32  can be defined as a square in which the corners are truncated or beveled; the beveled or truncated sections forming the curved short sides  38 . The ends  34  of the rotor  30  extend through openings  40  in the side walls  18  and  20 . At least one end of the rotor  30  is in a bearing assembly  42 , to allow the rotor to rotate within the housing  12 . The other end  34  of the rotor  30  can be operatively connected to, and supported by, a drive, such as a motor to rotate the shaft along its axis X. 
   A plurality of supports  50  are positioned on the rotor central section  32 . The supports, which, illustratively, are in the form of spiders, have a generally square base  52  having with a central opening  54 . The opening  54  is a generally square opening having straight sides  56  and curved, rather than sharp, corners  58 . The square opening  54  of the spider support is sized to fit over the rotor central section, such that the central section long sides  36  are adjacent the straight sides of the square opening  54 . Rods  60  ( FIG. 2 ) extend transversely through openings in the bases  52  to hold the spiders  50  together on the rotor  30 . A pair of arms or mounts  62  extends from opposite sides of each spider base. The arms  62  of adjacent spiders alternate, such that one set is vertical, the next is horizontal, the next is vertical, etc. Hammers or rings  64  are mounted between adjacent spiders which extend in the same direction. A hammer shaft  66  ( FIG. 2 ) extends through the arms  62 , and the hammers/rings  64  are journaled on the shafts  66 . As can be appreciated, the hammers/rings are positioned at intervals of 90° around the circumference of the rotor shaft  30 . The rotor shaft could be provided with more than two pair of opposing straight sides to reduce the interval between the hammers/rings. For example, if the rotor shaft had three pair of opposing straight sides, the hammers/rings could be spaced at intervals of 60° around the shaft. Four pair of opposing straight sides would allow for intervals of 45° between the hammers/rings. Alternatively, the rotor shaft could be formed with only one pair of opposing straight sides, such that the hammers/rings are positioned 180° apart from each other. This would require the use of spacers between the rings/spider arm bases. 
   In  FIG. 8 , an alternative embodiment of the support is shown. The support  50 ′ is shown in the form of a center disc having a plate  52 ′ with a central opening  54 ′. The central opening  54 ′ is substantially identical in shape to the opening  54  of the spider  50  ( FIG. 5 ). The disc  50 ′ includes inner openings  59 ′ through which the rod  60  extends. Six openings  59 ′ are shown, however, more or fewer openings could be provided to accommodate more or fewer rods. The disc  50 ′ also includes outer openings  65 ′ which are evenly spaced about the disk  50 ′ near the periphery of the disc. The openings  65 ′ are sized to receive the shaft  66  upon which the hammers/rings are mounted between adjacent discs  50 . Six openings  65 ′ are shown. More or fewer openings  65 ′ could be provided to accommodate more or fewer hammers/rings. 
   An alternate shaft or rotor  30 ′ is shown in  FIGS. 6 and 7 . As seen in  FIGS. 6 and 7 , the rotor  30 ′ includes a multi-sided central section  32 ′ and two cylindrical, stepped end sections  34 ′ extending from opposite sides of the central section. The central section  32 ′, at the approximate center of the rotor  30 ′, includes a raised hub  69  which has the same shape as the center section  32 ′. As seen in  FIG. 7 , the central section  32 ′ has eight sides, however, it could be formed with fewer sides or more sides, as desired. The central section  32 ′ as shown in  FIG. 7  includes four straight sides  36 ′ which are angled generally 90° to each other and four curved sides  38 ′ positioned between the straight sides  36 ′, and which are also angled generally 90° to each other. The curved sides  38 ′ define arcs of a circle. Thus, in cross-section, the rotor central section  32 ′ can be defined as a circle which is flattened along four sides to form the straight sides  36 ′. Alternatively, the central section  32 ′ can be defined as a square in which the corners are truncated or beveled; the beveled or truncated sections forming the curved sides  38 ′. The ends  34 ′ of the rotor  30 ′ extend through openings  40  in the side walls  18  and  20 . 
   The provision of the hub  69  allows for the supports (i.e., the center discs  50 ′ or the spiders  50 ) to be fixed to the shaft  30 ′ without the use of outer lock nuts to secure or tighten the rotor together. As can be seen at  FIG. 9 , shaft  70  incorporates its raised center portion  71 , and includes a pair of cross bar holds, as at  72  and  73 , held by the fasteners  74 , to secure the hammers  75  thereon. This holds the entire rotor assembly to the shown shaft. A grate  70   a  ( FIGS. 1 and 2 ) extends from the bottom of the inlet  24  beneath and around the rotor  30  and hammers/rings  64  in a generally arcuate fashion. The grate  70   a , as can be appreciated, will hold matter to be crushed in the housing to be impacted and crushed by the hammers/rings. As the material is crushed to a desired size, it will fall through the grate  70   a.    
   The use of the multi-sided rotor shaft  30 ,  30 ′ facilitates assembly of the supports  50 ,  50 ′ and hammers  64  to the rotor  30 , as well as operation of the crusher  10 . Because the shaft  30 ,  30 ′ includes the flat sides  36 ,  36 ′, and the support central openings  54 ,  54 ′ have the corresponding flat sides, the supports cannot rotate relative to the rotor shaft. Thus, the crusher  10  does not require keys and keyways, pins, bolts, or other fasteners to rotationally fix the supports to the rotor shaft central section  32 . Additionally, the corresponding shape of the rotor shaft central section  32  to the support central opening  54 ,  54 ′ causes the rotor shaft  30  to positively drive the spiders or center discs, and hence the hammers or rings. Again, because there are no keys and keyways, pin, bolts or other fasteners which secure the spiders to the rotor shaft, there are no keys and keyways, pins, bolts, or fasteners which might sheer during operation. Hence, the use of the multi-sided rotor shaft  30 ,  30 ′, with the supports having central openings corresponding in shape to the cross-sectional shape of the rotor reduces not only the construction costs of the crusher or mill  10 , but also reduces maintenance costs of the crusher or mill  10 . 
   As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. For example, although the rotor  30 , 30 ′ and the support central opening  54 ,  54 ′ are both shown to have at least two flat sides, both could be provided with a single flat side. This single flat side would still allow for the support to be rotationally fixed to the shaft or rotor without the use of keys, pins, etc. This example is merely illustrative.