Patent Document

RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/314,090, filed Aug. 21, 2001. 
    
    
     FIELD OF THE INVENTION 
     This invention pertains to apparatus and methods for screening debris from a materials reducing machine. In particular, this invention covers a product sizing screen set-up which can be removed from the side of the machine, easily interchanged, reversed or manipulated by an individual without undue expenditure of time and effort. 
     BACKGROUND OF INVENTION 
     Waste recyclers, or materials reducing machines are used to size reduce larger materials, such as wood debris from collection yards, land clearing or demolition-type activities. An example of one such materials reducing machine can be seen in U.S. Pat. No. 5,947,395 entitled Materials Reducing Machine. Generally, waste recycling machines consist of a large rotor that contains knives or hammer teeth spaced along the surface of the rotor. Material to be size reduced is fed into the machine. The teeth of the rotating rotor strike the incoming material, thereby chipping and shredding the debris into smaller sizes. The rotating rotor also advances the debris toward an anvil. The anvil is positioned such that the material hits the anvil, where the material is further reduced by a shearing action between the hammer teeth and the anvil. As the size reduced material passes the anvil it comes in contact with a series of screens or grates which are sized to permit only a desired size of material to pass and discharge from the machine. 
     The screen pattern and size of the holes can vary. For example, screens can have holes that are round, octagonal, square, etc. as well as varying diameters depending on the ultimate size of the end product desired by the user. Although the bulk of the material is reduced prior to engaging the screens, the screens can further act as a size reducer. In such a case, as the rotor advances the size reduced material past the screens the material gets further reduced by the hammer teeth grating material along the screen hole pattern, thereby shredding and further reducing the material, and forcing it out the screen holes. Often the need arises to change these screens. One reason to change the screens might be that the screen has been used long enough such that the bottom edges of the holes have dulled to the point that they are no longer effective in size reducing and screening the material. Screens may also need to be changed if the operator of the waste recycler desires a different product, which includes screening the material by a different size. In such cases the screens must be removed from the machine and replaced. 
     The screens are typically made of a heavy-duty material, such as steel, and are often extremely large, heavy and awkward to manipulate. To remove and replace a screen in current materials reducing machines, typically one or more individuals must completely disengage the machine and gain access to the screens through the top front portion of the machine. Access to the screens is obtained by pivoting what is known as the anvil housing upward such that the rotor is exposed and the screens surrounding the rotor can be removed. Typically, one screen, which is held into place by the anvil housing will be relatively accessible once the machine is open and the anvil housing is disengaged. The other screens, however, are more difficult to access as they must be slid up from toward the bottom of the rotor to the access opening created by the disengagement of the anvil housing, either by the operator&#39;s brut force, or by using some sort of mechanical assistance for sliding or rotating the screen up towards the access location. Further, the screens take a substantial amount of abuse during operation, which may cause the screens to deform and make removal thereof even more difficult. 
     Current materials reducing machines have proven to be cumbersome and extremely difficult for an operator to effectively and rapidly manipulate screens in order to change screens depending on product requirements or replace the worn out screens. As such, there exists a need for a materials reducing machine where the screens can be readily changed without significant disassembly and effort to access and remove the screens. 
     SUMMARY OF INVENTION 
     The present invention is directed to providing a readily removable and interchangeable screen system for material reducing machines. As described in the background of the invention, screens of current waste recycling machines cannot be removed, replaced or interchanged without significant loss of time and expending significant effort to access and remove the screens. 
     The enclosed embodiment of the present invention solves the problems associated with prior materials reducing machine screens by designing a machine in which the screens can be accessed and removed from the side of the machine, changed or rotated 180 degrees and replaced through the side of the machine, all without significant machine disassembly and effort by the operators. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side view of a materials reducing machine; 
         FIG. 2  is a partial perspective view of the materials reducing machine with the screens in the operational configuration; and 
         FIG. 3  is a partial perspective view of the materials reducing machine with the screens partially removed. 
         FIG. 4  is a side view of a materials reducing screen. 
     
    
    
     DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and which show by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents. 
       FIG. 1  illustrates a material reducing machine  10  with the outside walls removed, which is configured to reduce debris such as logs, stumps, limbs, and other materials into smaller sizes. Material reducing machine  10  can either be portable, i.e. on wheels or a trailer, or it may be fixed in a particular location to perform the task of size reducing debris. 
     In the illustrated embodiment, material to be reduced is fed into machine  10  at receiving bin  12 . The material is advanced toward a pivotal  15  and rotating  15 ′ hold down roller  14 , which compacts the material and helps propel it into the rotational path of rotor  16 . Rotor  16  is a large revolveable drum that has a number of rotor teeth  18  in spaced intervals located around the periphery of the rotor  16 . As the rotor teeth  18  strike the material fed from hold down roller  14 , the first size reducing of the material occurs, or what is known as the initial breakdown of the material. As the material passes the initial breakdown phase and revolves around rotor  16 , it strikes against anvil  20 , which is secured to first screen support member  22 , which is a pivotable housing upon which supports first screen  26 . Anvil  20  is positioned such that as the material hits anvil  20 , it is sheared and further reduced in size. This is also known as the secondary breakdown of the material. 
     The material that passes anvil  20  in the secondary breakdown phase is then ready for final sizing by screens  26 ,  30  and  32  located around a portion of the periphery of rotor  16 . The screen system, which in the illustrated embodiment is made up of three separate screens,  26 ,  30 , and  32 , (see FIG.  4  and discussed below) performs a dual function of further size reducing the material and allowing properly sized material to pass through the screens as final product. It can be appreciated by one skilled in the art that the number of screens need not be limited to three, but can be fewer or more depending on the composition of the feed material, machine size, application and desired product size. 
     First screen  26  does the majority of the material final sizing. Screen  26  is selected so that the hole pattern produces the appropriate sized final product. Though the material is primarily size reduced in the initial breakdown and secondary breakdown phases, material passing anvil  20  may still be too large to pass through the selected screen size of first screen  26 . As such, the holes of first screen  26  further size reduces the material by the action of the revolving rotor teeth  18  grating the material against the holes of first screen  26  (see  FIG. 4  for a drawing of a screen). This grating action further reduces the size such that it can pass through the holes of first screen  26 . The material that passes through the holes of first screen  26  is typically smaller than the hole size. For example, it has been found that the product passing through screens having a pattern of one inch diameter holes will be ¼ inch and smaller in size. 
     Material that is further reduced by the grating action but does not pass through the holes of first screen  26  can encounter more size reduction and pass through the holes of second screen  30  and third screen  32 . It has been found, however, that very little, if any size reduction occurs in the second screen  30  and third screen  32 . As such, it is often desirable to select the hole pattern and size of second screen  30  and third screen  32  to be slightly larger than the hole pattern size of first screen  26 , as the material will be adequately size reduced and no further size reduction need take place. However, if an extremely fine product is desired, selecting a smaller hole pattern for second screen  30  and third screen  32  would be advantageous. 
     First screen  26  is removably attached to first screen support member  22  through screen clamps  28 . First screen support member  22  pivots about pin  24  such that in the closed or operational position, the first screen  26  is in position to screen material and perform final sizing of the material (as is the position illustrated in FIG.  1 ). First screen support member  22  or which is sometimes referred to as an anvil housing is maintained in the operational configuration through the use of shear pin mechanism  25 , which will shear and allow first screen support member  22  and first screen  26  to move to a disengaged position if an ungrindable object is encountered. 
     To change first screen  26 , due to wear or if a different sized product is desired, first screen support member  22  pivots upward and outward on pivot pin  24 . First screen support member  22  can be pivoted manually or by mechanical assistance, such as a hydraulic cylinder and mechanical linkage. Screen clamps  28  can be removed, which allows first screen  26  to be pulled laterally outward perpendicular to the side of machine  10  and similarly replaced. 
     Second screen  30  and third screen  32  are held into the closed position by secondary screen support members  34 . In the illustrated embodiment, support members  34  are retaining bars that are sized to cradle the curved screens  30  and  32 . To change second screen  30  and/or third screen  32 , secondary screen support members  34  is lowered slightly by releasing tensioning mechanism  38 . As illustrated, a conventional clevis mechanism is used to raise and lower the secondary screen support members  34  thereby selectively applying and relieving tension. It can be appreciated by one skilled in the art, however, that any device that can selectively apply tension to the secondary screen support members  34  will work without departing from the scope of the invention, including hydraulic arms and the like. As further shown in  FIGS. 2 and 3 , multiple support members  34  can be used as needed to adequately support screens  30  and  32  along the length of rotor  16 . 
     As shown in  FIG. 1 , when tensioning mechanism  38  is released, the secondary screen support members  34  pivot about pin  36 , thereby releasing tension on screens  30  and  32 . Once the tension is relieved, second screen  30  and/or third screen  32  can be slid laterally out the side of machine  10 . This alleviates the need to rotate the screens upwardly and out the opening created by first screen support member  22  being in the open or disengaged position, as is required in the current materials reducing machines. As with first screen support member  22 , secondary screen support members  34  and tensioning mechanism  38  are maintained in the operational configuration through shear pin mechanism  39 , which allows disengagement of second screen  30  and third screen  32  if an ungrindable object is encountered. 
       FIG. 2  is a partial perspective view of the materials reducing machine with screens  26 ,  30  and  32  in the operation position, and cut outs in side wall  48  of machine  10 , which enable side removal. Screens  26 ,  30  and  32  are sized such that a portion of the screen end protrudes through the sides of machine  10 . In the illustrated embodiment, the ends of screens  26 , 30  and  32  have hand holds  31  (shown in  FIG. 4 ) cut therein to allow an operator to grasp the screens for removal and replacement. 
     As described above, to remove first screen  26 , first screen support member  22  must be pivoted toward the disengaged position. To do so, however, an access port  50  must be cut out of side wall  48  and appropriately sized to accommodate the swing path of the protruding ends of first screen  26 . Once in the disengaged position, screen clamps  28  can be removed so that first screen  26  is no longer attached to first screen support member  22 . Once clamps  28  are removed, first screen  26  can be pulled out of the machine through the first screen access port  50  in side wall  48 . 
     Referring to  FIG. 4 , first screen  26 , as with second screen  30  and third screen  32 , is symmetrical in shape from end to end. As such, first screen  26  can be removed, rotated 180 degrees and reinserted if one side of the holes are worn, or first screen  26  can be removed and replaced with a screen having a hole pattern of a different size and shape to produce a particular product size. Also, second screen  30  and third screen  32 , removal of which is discussed below, can be interchanged with each other or with first screen  26 . In the illustrated embodiment, hand holds  31  are cut into each end of the screens  26 ,  30  and  32  to enable an operator to grasp and remove the screens from the side wall  48  of machine  10 . As also shown in  FIG. 4 , clamps  28  as discussed with regard to first screen  26  above engage clamp slot  56 , which is tapered to enable a centering effect of the screen when screen clamp  28  engages clamp slot  56 . 
     Referring back to  FIG. 2 , second screen  30  and third screen  32  are removed through secondary slot  52  in side wall  48 . Secondary slot  52  is only slightly larger than the thickness of the screens  30  and  32 , as less clearance is required for second screen  30  and third screen  32  to be laterally slid out the side of machine  10 . In the operational configuration, secondary screen support members  34  keep second screen  30  and third screen  32  in position by forcing them against the top portion of secondary access port  52  cut out of side wall  48 . Tension on the secondary screen support members  34  is regulated by retaining bar tensioning mechanism  38 , as discussed above with respect to FIG.  1 . As multiple secondary screen support members  34  can be used, a linkage  35  can be used to enable a variety of tensioning mechanisms to raise and lower support members  34 . When the operator desires to remove either second screen  30  or third screen  32 , the tension on secondary screen support members  34  is relieved and secondary screen support members  34  pivot downwardly on pivot pin  36 . Accordingly, second screen  30  and third screen  32  drop downwardly and rest against the bottom side of secondary screen access port  52 . Once in the disengaged position, either second screen  30  or third screen  32  can be removed by pulling the selected screen through secondary screen access port  52  in side wall  48 . As with the first screen  26 , once removed, screens  30  and  32  can be replaced if worn, interchanged with one another, rotated 180 degrees, or can be interchanged with the first screen  26 . 
     Though the illustrated embodiment shows cut outs in side wall  48  creating access ports  50  and  52 , one skilled in the art will appreciate that side wall  48  can be removed in order to gain access to screens  26 ,  30  and  32 , whereby they can be removed out the side of machine  10 . It is preferred, however, for the side walls  48  to remain in place and the screens  26 ,  30  and  32  be removed through access ports  50  and  52  to minimize time and effort required to change or rotate screens. 
       FIG. 3  shows screens  26 ,  30  and  32  partially removed from the side of machine  10 . In regards to fist screen  26 , first screen support member  22  is in the disengaged position, screen clamps  28  (not shown in  FIG. 3 ) are removed from their attachment point  29  on first screen support member  22 . First screen  26  is partially pulled out of first screen access port  50  using hand holds  31 . For second screen  30  and third screen  32 , tensioning mechanism  38  is extended to relieve the tension on secondary screen support members  34  (not shown in FIG.  3 ). Second screen  30  and third screen  32  can then be pulled out the secondary screen access port  52  in side wall  48  using hand holds  31 . 
     Referring back to  FIG. 2 , to enable secondary slot  52  and first screen access slot  50  to be cut into the side wall  48 , and to provide unobstructed access to screens  30  and  32 , rotor bearing housing  40  cannot be traditionally mounted, i.e. with rotor bearing housing support  60  horizontally affixed to the lower portion of machine  10 , as is done in current materials reducing machines. To do so blocks access to the screens and prevents side removal. Rather, the mounting assembly for rotor bearing housing  40  must be reconfigured such that rotor bearing housing support  60  is mounted in a way that does not block access to screens  26 ,  30  and  32 . 
     In the illustrated embodiment, rotor bearing housing support  60  mounts vertically to the side, such that it would not interfere with removal of screens  26 ,  30  and  32 . To provide the necessary support, rotor bearing housing  40  and rotor bearing housing support  60  are supported off to the side by support brackets  62  and  64 , which are integral with the side wall  48  of machine  10 . Though not illustrated, rotor bearing  40  and rotor bearing housing support  60  can be similarly mounted to the upper side of the materials reducing machine  10  such that access to screens  26 ,  30  and  32  is unobstructed. 
     To reinforce side wall  48  with first screen access slot  50  and secondary slot  52  cut out, reinforcement bracket  66  is used. This enables the protruding portion of second screen  30  and third screen  32  to be forced against the top edge of secondary slot  52  by secondary screen support members  34  in the operational configuration, as well as the first screen  26  to be forced against the inside edge of first screen access port  50  by first screen support member  22  in the operational configuration without side wall  48  buckling or deforming. For lighter operations, support bracket  66  may not be necessary. 
     Those skilled in the art would recognize that though a three screen system is depicted and described, fewer or more screen may be used depending on the operational situation, size of the machine, and nature of the material being size reduced. For larger machines, more screens may be employed in order to keep the weight of each individual screen section to a point that can be maneuvered by an individual (e. g. 100 pounds). It can also be appreciated by one skilled in the art that the described and illustrated support structure for the rotor bearing housing can be number of configurations to provide adequate support for the rotor bearing housing  40  without departing from the spirit of the invention, which includes providing unobstructed access through the side wall  48  of machine  10  to screens  26 ,  30  and  32 . 
     Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the specific embodiment shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.

Technology Category: b