Patent Abstract:
A rotary knife for a granulator having a two-piece design comprising a blade holder and a removable blade, the blade holder having a V-shaped saddle for holding the removable blade aligned. The V-shaped saddle having a flat surface for absorbing the shock of force transmitted by the blade shearing plastic and other materials for recycling and reuse.

Full Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to blades used in granulators, grinders or mulchers for reducing waste such as plastic pieces to pellets or chips. Such machines when used with plastic are typically part of a manufacturing line to grind scrap parts for melting and reformation into new parts. The machine typically comprises an input hopper gravity feeding into a shear comprising a rotary component having a plurality of blades mounted thereon positioned to chop with a fixed bed blade. More particularly, the present invention comprises a modular rotary blade having a removable edge adapted to reduce maintenance and downtime, 
       BACKGROUND OF THE INVENTION 
       [0002]    Granulators are part of a class of machines used to reduce scrap to chips or small pieces. These machines are used to regrind plastic parts for remelting and forming into new parts. Similar machines are used to grind trees and wood cuttings into mulch, grind automotive tires for recycling and chop electronic parts for separation of materials and precious metals. Screens are used in the cutting chambers to sort out pieces that are of a desired size. The pieces are cut or chopped until they are of a size to escape the cutting chamber and fall into the output bin or discharge. 
         [0003]    The machines are configured to grind or chop a particular material with the blades selected to perform the necessary cutting action. The blades are formed from hardened steel or alloy and the cutting edge ground depending on the material to be processed. Continuous hard use and shocks to the blade may damage them requiring the place to be removed and be sharpened. The shock absorbed by the blade may be caused by foreign objects dropped into the hopper. Foreign objects such as nuts or bolts, personal jewelry, etc., may fall into the granulator from time to time and cause damage to the blades. The blades may also need to be resharpened after use. 
         [0004]    Typically the blades on the rotary cutter are kept together in a set. The blades are ground to a preselected dimension. Likewise the bed blades are treated as a set and similarly ground together to a preselected dimension. The blades when assembled on the machine require a calibration of the rotary cutter and the bed blades to adapt the positioning for cutting in a desired dimension. Replacing the blades and adjusting the machine requires downtime of the machine. Further, the blades are expensive due to the high quality material used. 
         [0005]    Multipart blades have been designed to use a hardened steel cutter blade attached to a soft steel carrier. These blades require a large carrier and fasteners are to absorb the shock of the cutting action. The weight of these blades make shipping the blade for resharpening expensive. In addition, the construction of these blades demands the blades be expensive. Accordingly, it is desirable to have a cutting blade that may be retrofitted on a standard rotor having an inexpensive, blade holder formed of plastic, composite or inexpensive metal and a cutter blade of tool steel removably Attached thereon. The cutter blade securely fastened to the blade holder and adapted to directly transferred the shock of the cutting action to the late holder. The cutter blade being removable from the blade holder to allow shipping only the cutter blade for resharpening. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    One embodiment of the present invention is directed to a multipart blade for attachment to a rotor of the granulator. The multipart blade having a blade holder made of an inexpensive material such as plastic, a composite or steel and a cutting blade formed from a hardened alloy or tool steel. The blade holder having a shape and mounting configuration of a standard rotor blade and a V-shaped saddle for receiving the rotor cutting blade. 
         [0007]    The blade holder having a body extending the length of the rotor cutting blade. The body having a plurality of mounting holes for attaching to the rotor. The blade holder further comprising a V-shaped saddle formed along the front edge. The V-shaped saddle extending the length of the blade holder. The V-shaped saddle having a first side, second side and a first edge. The first side and the second sidedisposed at a predetermined angle to each other. One of the sides adapted to be generally perpendicular to the shock force applied to the blade when mounted to the rotor and chopping material. A blade hole is formed extending from the back edge to the V-shaped saddle in the front edge. The blade hole extending through the first edge. 
         [0008]    The cutting blade having a cutting edge, two sides and a mounting edge. The cutting blade may be formed of a hardened steel or alloy such as D2. The mounting edge having a V-shaped mounting edge adapted to fit into the V-shaped saddle. A carrier hole is formed in the mounting edge having a carrier hole axis generally parallel to one of the two sides. The carrier hole disposed along the mounting edge to align with the blade hole in the blade holder. A threaded fastener extended into the blade hole from the back edge of the blade holder extending through the V-shaped saddle and into the carrier hole is used to hold the cutting blade in the V-shaped saddle. 
         [0009]    The above description sets forth, rather broadly, the more important features of the present invention so that the detailed description of the preferred embodiment that follows may be better understood and contributions of the present invention to the art may be better appreciated. There are, of course, additional features of the invention that will be described below and will form the subject matter of claims. In this respect, before explaining at least one preferred embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and to the arrangement of the components set forth in the following description or as illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0010]      FIG. 1  is a section view of the granulator assembly illustrating the first embodiment mounted on the rotor. 
           [0011]      FIG. 2  is an end plan view of the first embodiment. 
           [0012]      FIG. 3  is a side elevation view of the first embodiment. 
           [0013]      FIG. 4  is a perspective view of the first embodiment. 
           [0014]      FIG. 5  is a bottom plan view of the first embodiment. 
           [0015]      FIG. 6  is an exploded perspective view of the first embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part of this application. The drawings 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 changes may be made without departing from the scope of the present invention. 
         [0017]    Referring to  FIG. 1 , the present invention comprises a blade for use and a granulator, generally indicated by reference number  10 . The granulator  10  comprises a generally rectangular box shape body  12  having a rotor  20  used to chop pieces of plastic waste  12 . The granulator may comprise a frame  11 , an input chamber  14 , and a discharge chamber  16 . The input chamber  14  and discharge chamber  16  separated by a screen  17 . Chopped pieces of plastic  18  are formed by the rotor  20  carrying rotor blades  22  rotating about rotor axis  21 . The rotor  20  rotates in a direction indicated by arrow R causing the rotor blades  22  to interface with bed blades  26  in cutting force direction F to reduce plastic  12  to pieces  18 . 
         [0018]    Continuing to refer to  FIG. 1 , granulator  10  further comprises a discharge chute  28  and a door  30  having a handle for accessing the discharge area  16 . Threaded fastener  32  may be used to attach rotor blade  22  to rotor  20  along outer peripheral edge  23 . Likewise, threaded fastener  34  may be used to attach bed blades  26  to granulator frame  11 . 
         [0019]    Referring to  FIG. 2 , the rotor blade  22  further comprises blade holder  40  and cutting blade  42 . Blade fastener  44  extends through blade hole  46  threadably engaging cutting blade  42  at carrier hole  48 . The V-shaped saddle  50  formed along the front edge  51  of blade holder  40 , the V-shaped saddle  50  further comprising a first saddle side  52 , second saddle side  54  and inner edge  55 . First saddle side  52  and second saddle side  54  disposed at a saddle angle of approximately 45° angle. Blade holder  40  may be formed from metal, composite or plastic. Rotor blade  22  a formed of tool steel such as D-2. 
         [0020]    Continuing to refer to  FIG. 2 , cutter blade  42  comprises first mounting side  56  and second mounting side  58  adapted at a saddle angle to each other to fit into the V-shaped saddle  50 . The saddle angle A may be approximately 45° for adapting to a similarly formed V-shaped saddle. Cutter blade  42  further comprises a cutting edge  64  defined by first cutting side  60  and second cutting side  62  which may be ground to a particular edge configuration  59 . Blade side  61  between first mounting side  56  and second cutting side  62  and blade side  63  between second mounting side  58  and first cutting side  60  provide additional tool steel material to allow cutter blade  42  to be resharpened. In a low profile cutter blade  42 , first cutting side  60  may be on second mounting side  58  and second cutting side  62  may be on first mounting side  56 . Cutter blade  42  disposed in V-shaped saddle  50  may have first saddle side  52  bearing against second mounting side  58  and second saddle side  54  bearing against first mounting side  56 . Carrier hole  48  and laid hole  46  are lined to allow insertion and engagement by the blade fastener  44 . Blade  42  may be sharpened to have first blade step  67  second blade step  71  adjacent edge  64 . 
         [0021]    Referring to  FIG. 3 , granulator blade  22  may have cutting blade  42  mounted on blade holder  40  at V-shaped saddle  50 . Blade holder  40  may have an outside  66  and a back edge  68 . Back edge  68  is spaced from V-shaped saddle  50 . A mounting hole  70  preformed through blade holder  40  having a recess  72  formed in the outside  66 . the mounting hold  70  is disposed in a standard blade configuration for retrofit without modification to the rotor  20 . 
         [0022]    Referring to  FIG. 4 , the granulator blade  22  may have the cutting blade  42  formed at approximately the same length as the blade holder  40 . A pair of cutting blade sides  61 ,  63  may be adapted to align with holder inside  69  and outside  66  respectively. Blade holes  46  are spaced intermediate mounting holes a  70  and adapted to allow removal of the blade  42  without removal of the holder  40  from the rotor  20 . 
         [0023]    Referring to  FIG. 5 , blade holes  46  are formed in back edge  68  extending through to the V-shaped saddle  50 . Mounting holes  70  extend from the outside  66  of the blade holder  40  through the blade holder  40  to inside  69 . 
         [0024]    Referring to  FIG. 6 , the cutting blade  42  has a mounting surface  57  which may be adapted to fit into the V-shaped saddle  50 . Carrier holes  48  are disposed to align with the blade holes  46  for insertion of blade fastener  44 . First of mounting side  56  and second mounting side  58  may be disposed at a substantially similar angle to the saddle angle between first saddle side  52  and second saddle side  54 . 
         [0025]    Referring to  FIG. 7 , inner edge  55  of V-shaped saddle  50  is formed approximately at cutter blade axis  80 . First cutting side  60  and second cutting side  62  are formed at the blade axis  82 . Cutter blade axis  80  is in spaced relation to blade axis  82 . Cutting edge  64  is formed in spaced relation to edge axis  82  to direct the cutting force F, at a force angle of attack, approximately perpendicular to first saddle side  52  and second mounting side  58 . Cutting force F is directed on to rotor blade  22  has cutting edge  64  to engage plastic piece  12  with bed blade  26 . Bed blade  26  likewise may comprise a blade carrier  86  with a removable blade  88  adapted to be positioned to cause a shearing force on plastic piece  12  as rotary blade  22  rotates about rotor axis  21  and moves into engagement position with bed blade  26 . 
         [0026]    Continuing to refer to  FIG. 7 , rotor blade  22  is attached to rotor  20  and adapted to engage bed blade  26 . Plastic waste  12  is chopped by the cutting action between rotor blade  22  and bed blade  26 . Bed blade  26  is securely fastened to granulator frame  11 . Rotor blade  22  is securely fastened to rotor  20 . Rotor blade  22  comprises a blade holder  40  having a V-shaped saddle  50  disposed to orient one of the first saddle side  52  or second saddle side  54  approximately perpendicular to cutting force direction F. 
         [0027]    In use, the cutting blade holder  40  is mounted to the rotor  20  rotation about center axis  21 . The bed blade  26  may be adjusted and attend gentle direction to the rotation of rotor  20  and are to position the rotor blade  26  because a cutting action in conjunction with rotor blade  22 . Rotor blade  22  may have cutting blade  42  attached to blade holder  40 . As pieces of material  12  are granulated by interface of the rotor blade  22  with the bed that blade  26 , small pieces  18  well exit to screen  17  and out through discharge chute  28 . Cutting blade  42  may become doll true continued use or by hitting a foreign object  90  ( FIG. 7 ). Cutting blade  42  may be removed from rotor  20  without removal of the blade holder  40  to reduce downtime. 
         [0028]    It should be understood, the plurality of rotor blades  22  may be attached to rotor  20 . Each rotor blade is essentially identical in size and configuration. The discussion here and discusses a single rotor blade however is understood the discussion applies to each of the individual rotor blades use on a rotor  20 . The removable blade  22  is mounted on the rotor  20  having one of the first saddle side or second saddle side  52 ,  54  approximately radially aligned with a diameter of the rotor  20 . This alignment of the first saddle side or second saddle side  52 ,  54 , together with the offset position of the cutting edge  64  such that axis  82  ( FIG. 2 ) is approximately tangential to the diameter of the rotor  20  to direct the force F applied to the rotor knife when cutting plastic pieces  12 , or other material, against the radially aligned side  52 ,  54 . 
         [0029]    Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the embodiments of this invention. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents rather than by the examples given. Further, the present invention has been shown and described with reference to the foregoing exemplary embodiments. It is to be understood, however, that other forms, details, and embodiments may be made without departing from the spirit and scope of the invention which is defined in the following claims.

Technology Classification (CPC): 1