Patent Publication Number: US-2010108794-A1

Title: Auger for vertical mixer

Description:
FIELD OF THE INVENTION 
     The present invention is directed to vertical mixers and more specifically to vertical augers for use with vertical mixers. 
     BACKGROUND 
     Feed for livestock typically includes different ingredients that are required to be mixed together before they are provided to the livestock. For example, hay may be mixed with a variety of feed supplements, such as vitamins, to provide a bulk material. Various mixers are known that are designed to mix the bulk material to a desired extent. Vertical mixers are disclosed, for instance, in U.S. Pat. No. 5,863,122 (Tamminga) and in U.S. Pat. No. 5,462,354 (Neier). 
     Many prior art feed mixers include a tub having one or more walls and a floor defining a mixing chamber, with a mixing means, typically one or more augers vertically positioned in the mixing chamber comprising knives for cutting the bulk material as the auger rotates. In conventional use, the components of the bulk material are cut and mixed together by rotation of the auger. After mixing, the mixed bulk material is removed from the tub via a discharge opening and dispensed as appropriate, usually through the use of a conveyor. 
     The amount of bulk material to be mixed is usually relatively large. For example, a load of bulk material in a mixer can weigh as much as 10,000 lbs. or more. Mixing of the bulk material is typically slow and unloading of mixed bulk material is also very time consuming thereby increasing wear on the machine, fuel consumption, man hours, maintenance, etc. 
     A further issue associated with augers for vertical mixers is that rotation of the auger has a tendency to pack mixing bulk material toward the outer perimeter of the mixing chamber. This can also push bulk material up the side wall of the mixing chamber and over the top of the tub resulting in both a loss of bulk material and a decreased usable volume of the tub of the mixing chamber. 
     Further, once a bale has been placed in the mixing chamber and loosened such that it has lost most of its bale form and/or loose material has separated from the original bale, bridging of the loosened longer fibrous material can occur. Bridging of the loosed bulk material typically takes place substantially midway up the auger and therefore knives on the top flighting are generally useless at reducing or preventing bridging as they do not directly impact the bridging of loosened longer fibrous material in the bulk material. Additionally, a less densely packed area, substantially hollow, is formed at the bottom of the auger caused by the bridging longer fibrous material in the bulk material which, among other things, can result in a less efficient mix quality and/or increasing mix time. Additionally, the hay bale core can have a tendency to not process properly. 
     Vertical mixers tend to have difficulty discharging longer fibrous materials such as straw or hay. While discharging, fibrous materials are trapped by wrapping around the back edge of the discharge opening. This can both impede the flow of mixed bulk material out of the door and create a pressure point on the mixer wall at the bottom of the back edge of the discharge opening every time the end of the auger travels in close proximity to it. This pressure point can cause the wall of the mixer to bend out, can cause stress on both the power unit and the driveline/gearbox to the point of breaking components such as shear bolts, can deform the discharge opening, in particular the back edge thereof and can impede the door from closing. Loud noises associated with some of these side effects can also scare the livestock which can cause a reduction in quality and/or quantity of milk or meat production. 
     A further problem brought on at least partially from the trapping of the fibrous materials around the edge of the discharge opening is uneven discharge of the mixed bulk material. Based on the feeding pattern of livestock, for example cows, this can have a negative impact on milk/meat production. 
     A need therefore exists for an auger for a vertical mixer that overcomes or mitigates at least one of the problems outlined above or a further problem associated with existing augers and/or vertical mixers. 
     SUMMARY 
     A vertical mixer for mixing bulk material is provided including an auger having an auger post and flighting including upper flighting and a lower or bottom flight. In one example, the auger includes an angled knife connected to an outside edge of the flighting and oriented so that a blade of the angled knife is positioned at an angle suitable for allowing the angled knife to at least partially cut loosened bulk material that may be bridging in the mixing chamber thereby at least partially preventing or reducing bridging in the mixing chamber and allowing the bulk material to fall towards the floor of the mixing chamber increasing the cutting action of the cutting knives. 
     The vertical mixer for mixing bulk material may further or alternatively be provided comprising an auger for mixing bulk material. The auger uses one or more cutting knives positioned at a peripheral location directly or indirectly on a lower flight of the auger in a location that passes through material trapped on the discharge opening of the mixing chamber when the auger is rotated. The one or more cutting knives cuts trapped material away from the discharge opening thereby freeing the trapped material and allowing for quicker discharge of the mixed bulk material. The one or more cutting knives may be substantially vertically oriented or may be substantially parallel to the discharge opening. 
     In one illustrative embodiment there is provided a vertical mixer for mixing bulk material, the vertical mixer comprising:
         a mixing chamber for receiving the bulk material, the mixing chamber being defined by a floor and a peripheral wall, the mixing chamber comprising a discharge opening including a back edge, the discharge opening for discharging mixed bulk material, and a door for covering the discharge opening, the door moveable between an open and closed position;   a vertical auger in the mixing chamber, the vertical auger comprising
           an auger post;   depending flighting comprising an outside edge defining the perimeter of the flighting, the flighting including upper flighting positioned above a lower flight;   an angled knife connected to the outside edge of the upper flighting, the angled knife comprising a blade oriented at an angle upward relative the adjacent flighting to at least partially cut loosened bulk material bridging in the mixing chamber.   
               

     In another embodiment of the vertical mixer outlined above, the vertical auger further comprises at least one cutting knife positioned on the outer edge of the flighting for cutting bulk material as the auger rotates, the cutting knife oriented at an angle closer to parallel with the floor of the mixing chamber than the angled knife. 
     In another embodiment of the vertical mixer outlined above, the angled knife is connected to the upper flighting in a section below the top of the flight. 
     In another embodiment of the vertical mixer outlined above, the blade is oriented at an angle of from about 15° to about 110°, about 25° to about 90°, about 30° to about 90°, about 30° to about 60°, approximately 45°, at least approximately 30° or at least approximately 45° from the floor of the mixing chamber. 
     In another embodiment of the vertical mixer outlined above, the blade is oriented to draw bulk material into the flighting. 
     In another embodiment of the vertical mixer outlined above, the front end of the blade is further from the auger post than the rear end of the blade to draw bulk material into the flighting. 
     In another embodiment of the vertical mixer outlined above, the angled knife further comprises:
         a connector plate comprising an auger connection section for connection with the auger flighting and a blade connector section for connection to the blade.       

     In another embodiment of the vertical mixer outlined above, the angled knife is mounted rearward and adjacent one of the cutting knives. 
     In another embodiment of the vertical mixer outlined above, the vertical auger further comprises an additional angled knife. 
     In another embodiment of the vertical mixer outlined above, the additional angled knife is connected to the lower flight or the upper flighting. 
     In another embodiment of the vertical mixer outlined above, the additional angled knife is mounted rearward and adjacent the angled knife. 
     In another embodiment of the vertical mixer outlined above, the blade of the angled knife and the cutting knife are integrated into one knife. 
     In another embodiment of the vertical mixer outlined above, on the vertical auger the lower flight comprises a front leading edge and an outside edge defining an outside footprint of the lower flight; and the vertical auger further comprises:
         a first lower cutting blade connected indirectly or directly to the lower flight of the vertical auger at a first connection point, the first lower cutting blade situated to pass proximate the back edge of the discharge opening during rotation of the auger to cut material trapped on the back edge of the discharge opening.       

     In another embodiment of the vertical mixer outlined above, the first connection point is proximate the leading edge of the lower flight. 
     In another embodiment of the vertical mixer outlined above, the vertical auger further comprises:
         a second lower cutting blade connected indirectly or directly to the lower flight of the vertical auger at a second connection point, the second lower cutting blade situated to pass proximate the back edge of the discharge opening during rotation of the auger to cut material trapped on the back edge of the discharge opening; and   wherein the first connection point is proximate the front leading edge of the lower flight and the second connection point is rearward of the first connection point.       

     In another embodiment of the vertical mixer outlined above, the first lower cutting blade is oriented to be substantially parallel to the peripheral wall at the back edge of the opening. 
     In another embodiment of the vertical mixer outlined above, the second lower cutting blade is oriented to be substantially parallel to the peripheral wall at the back edge of the opening. 
     In another embodiment of the vertical mixer outlined above, the first lower cutting blade is oriented to be substantially vertical. 
     In another embodiment of the vertical mixer outlined above, the second lower cutting blade is oriented to be substantially vertical. 
     In another embodiment of the vertical mixer outlined above, the first lower cutting blade comprises a shallow angled front corner having an angle of between about 1 and 45 degrees or about 15 degrees. 
     In another embodiment of the vertical mixer outlined above, the second lower cutting blade comprises a shallow angled front corner having an angle of between about 1 and 45 degrees or about 20 degrees. 
     In another embodiment of the vertical mixer outlined above, the first lower cutting blade is mounted so that a back end of the first cutting knife is further from a point on the wall of the mixing chamber than a front end of the first lower cutting blade when passing the point during rotation of the auger. 
     In another embodiment of the vertical mixer outlined above, the second lower cutting blade is mounted so that a back end of the second lower cutting blade is further from a point on the wall of the mixing chamber than a front end of the second lower cutting blade when passing the point during rotation of the auger. 
     In another embodiment of the vertical mixer outlined above, the vertical auger further comprises:
         a slide plate connected to the lower flight for guiding bulk material, the slide plate comprising:
           a front corner;   a bottom edge; and   a top edge opposite the bottom edge;   
           the slide plate extending from the lower flight beyond the outside edge of the lower flight toward the peripheral wall of the mixing chamber; and   wherein the first lower cutting blade is connected to the slide plate.       

     In another embodiment of the vertical mixer outlined above, the vertical auger further comprises:
         a second lower cutting blade connected to the slide plate at a second connection point, the second lower cutting blade situated to pass proximate the back edge of the discharge opening during rotation of the auger to cut material trapped on the back edge of the discharge opening;   wherein the first connection point is near the top edge and the front corner of the slide plate and the second connection point is rearward of the first connection point near the top edge of the slide plate.       

     In another illustrative embodiment there is provided a vertical mixer for mixing bulk material, the vertical mixer comprising:
         a mixing chamber for receiving the bulk material, the mixing chamber being defined by a floor and a peripheral wall, the mixing chamber comprising a door for allowing exit of mixed bulk material;   a vertical auger in the mixing chamber, the vertical auger having an auger post and flighting including a lower flight; and   a spacer device directly or indirectly connected to the lower flight of the auger, the spacer device comprising a component extending below the bottom flight of the auger for contact with the floor of the mixing chamber.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric cutaway view of one embodiment of a vertical mixer with a single auger with an example of an angled knife; 
         FIGS. 2A ,  2 B and  2 C are top, isometric and side views, respectively, of one embodiment of an auger for a vertical mixer with an angled knife; 
         FIGS. 3A and 3B  are isometric views of an assembled and exploded, respectively, angled knife for an auger for a vertical mixer; 
         FIGS. 4A ,  4 B and  4 C are top, exploded and side views, respectively, of another embodiment of an auger for a vertical mixer with multiple angled knives; 
         FIG. 5  is an isometric cutaway view of another embodiment of a vertical mixer with dual augers with an example of an angled knife; 
         FIG. 6  is an isometric view illustrating one example of a vertical mixer; 
         FIG. 7  is a side view illustrating one example of an auger for a vertical mixer; 
         FIG. 8A  is a top view of the auger for a vertical mixer illustrated in  FIG. 7 ; 
         FIG. 8B  is an elevated view of the auger for a vertical mixer illustrated in  FIG. 7 ; 
         FIG. 8C  is a side view of the auger for a vertical mixer illustrated in  FIG. 7 ; 
         FIG. 9A  is an exploded isometric view of an auger for a vertical mixer including both lower cutting blades and angled knives; 
         FIG. 9B  is an isometric view of an auger for a vertical mixer including both lower cutting blades and angled knives; 
         FIG. 9C  is a top view of an auger for a vertical mixer including both lower cutting blades and angled knives; 
         FIG. 10A  is an isometric view illustrating another example of a vertical mixer with the door in the open position comprising an example of an auger; 
         FIG. 10B  is top-view of the vertical mixer and auger of  FIG. 10A ; 
         FIG. 11A  is a graph illustrating the power, speed and torque of a conventional vertical mixer during a mixing and unloading phase; and 
         FIG. 11B  is a graph illustrating the power, speed and torque of a vertical mixer having at least two cutting knives during a mixing and unloading phase. 
     
    
    
     DETAILED DESCRIPTION 
     Angled Knife 
     One embodiment of a vertical mixer having an example of a vertical auger is described with reference to  FIG. 1 . A vertical mixer  50  has a mixing chamber  100  for receiving bulk material to be mixed. The mixing chamber  100  has an open top  130  for receiving the bulk material, a floor  120 , and depending walls  110  defining the mixing chamber  100 . A vertical auger  20  is situated in the mixing chamber  100  in a conventional fashion. The mixing chamber  100  includes a door  140  through which mixed bulk material exits the mixing chamber  100  when the door  140  is opened. The auger  20  includes cutting knives  240  connected along an outside edge of the flighting of the auger  20  for cutting bulk material as the auger rotates. The cutting knives  240  generally have an orientation of parallel or near parallel the floor  120  of the mixing chamber  100 . As the auger  20  rotates, bulk material is mixed and cut. However, bridging may occur as the loosened fibrous bulk material, such as hay, is forced upwards and tends towards the outer perimeter of the mixing chamber  100  as well as toward the top of the auger  20 . To reduce and/or mitigate this problem, an angled knife  300  is mounted to the auger  20  along an outside edge and oriented so that the angled knife  300  is more upright than the cutting knives  240 . Typically, the angled knife  300  is oriented to angle upward relative the adjacent flighting to which the angled knife  300  is mounted. The angled knife  300  may be mounted behind one of the cutting knives  240 . The angled knife  300  may be mounted above the lower flight of the auger  20  as will be explained in more detail below with reference to  FIGS. 2 ,  4  and  5 . The angled knife  300  is positioned at a suitable location on the auger  20  to cut a hole in the bridging fibrous bulk material allowing the material to drop down into the auger  20 . This allows the cutting knives  240  to go be exposed to the fibrous bulk material more quickly and more often during rotation of the auger  20  thereby increasing cutting of the fibrous bulk material by the cutting knives  240 . 
     One embodiment of an example of an auger  20  is shown with reference to  FIGS. 2A ,  2 B and  2 C. As will be appreciated by one of ordinary skill in the art, the auger  20  includes an auger post  200  around which there is depending flighting  210  for mixing bulk material deposited in the mixing chamber  100  during rotation of the auger  20 .  FIG. 2B  shows the auger  20  with an exploded view of an example of an angled knife  300  before attachment to the auger flighting  210 . The angled knife  300  is connected along the outside of the flighting  210 . As shown in  FIGS. 2A ,  2 B and  2 C the angled knife  300  may be connected rearwards of a cutting knife  240 . The angled knife  300  includes a blade  315  oriented to be angled upwards relative the cutting knife  240 . Typically, the angled knife  300  has the blade  315  with an angle of between about 15° to about 110° from the floor  120  which is generally substantially horizontal. The blade  315  may alternatively have an angle of between about 25° and about 90°, between about 30° and about 60° or alternatively may have an angle of approximately 45°. Alternatively, the blade  315  may be oriented to have an angle of at least 30° or at least 45°. It is important that the angled knife  300  have an angle suitable for at least partially cutting into the loosened fibrous bulk material that may have bridged during rotation of the auger  20  so that the bridging is reduced or eliminated and the fibrous bulk material more easily falls to the bottom region of the auger  20  so that the cutting knives  240  are more effective in cutting the bulk material and/or the flighting  210  is more effective at mixing the bulk material. 
     The angled knife  300  is shown in  FIGS. 2A ,  2 B and  2 C as being attached to the auger  20  on the flighting  210 . More specifically, the angled knife  300  may be attached to a region of the flighting of the auger  20  above the lower flighting  215 . This region will be referred to as the upper flighting  216  and includes all flighting of the auger  20  partially or fully above a lower revolution of flighting, referred to as the lower flighting  215 . When an additional angled knife is used, as will be described with reference to  FIGS. 4A ,  4 B and  4 C, the additional angled knife may be located on any region of the flighting  210  including the upper  216  and lower flighting  215 . 
       FIGS. 2A ,  2 B and  2 C illustrate the angled knife  300  as being connected to the auger flighting  210  using a connector plate  305 . The connector plate  305  is mounted to the auger flighting  210  and includes a mounting section (shown in  FIGS. 3A and 3B ) for mounting the blade  315  thereon. It will be appreciated that the angled knife  300  may be connected to the auger  20  using any suitable method such as bolting, riveting, welding, etc. Alternatively, the angled knife  300  may be a single piece having the connector plate  305  and the blade  315  integrated together. The connector plate  305  is shown as being connected to the underside of the auger flighting  210 . This is not meant to be limiting. The connector plate  305  may alternatively be connected to the upper side, or both sides of the flighting  210 . 
     The angled knife  300 , when mounted on the auger  20 , provides for at least one of the following. Less bridging is experienced during mixing and cutting of loosened fibrous bulk material. As a result, the bulk material and particularly fibrous bulk material such as hay, is cut and mixed more quickly. As such, fewer man hours are required to process the bulk material for use, for example as feed, bedding, etc., as demonstrated for example in the test results outlined below. Less bulk material is thrown and lost out of the top of the mixing chamber  100  because the mixing bulk material is encouraged to drop down towards the floor  120  of the mixing chamber  100  where the cutting knives  240  can more effectively cut the fibrous bulk material. Because of the dropping action of the bulk material and the decrease in bridging, a larger volume of fibrous bulk material may be processed by a vertical mixer as compared to a similar vertical mixer without an angled knife attached to the auger. This is demonstrated for example in the test results outlined below. 
     The angled knife  300  may be oriented to draw bulk material into the flighting  210  of the auger  20 . One orientation that may be used in doing so is to place the front end of the angled knife  300 , relative to the direction of the rotation of the auger  20 , at a distance further from the auger post  200  than the rear end of the angled knife  300 . By doing so, bulk material contacting the angled knife  300  is drawn into the flighting  210  instead of being pushed outward toward the wall  110  of the mixing chamber  100 . 
       FIGS. 3A and 3B  show an illustrative embodiment of an angled knife  300 . As outlined above, the angled knife  300  may be connected to the auger in an suitable manner such that the angle knife  300  is oriented to be at an angle upwards from the adjacent flighting to which the angled knife  300  is connected for cutting loosened fibrous material that may be bridging in the mixing chamber.  FIGS. 3A and 3B  simply show an illustrative embodiment that may be used for connecting the angled knife  300  to an auger. 
     The angled knife  300  comprises a blade  315  for cutting bulk material. The blade may optionally have a serrated edge  320  to increase cutting efficiency. Further included is a connector plate  305  for connection to the flighting of the auger and for attachment to the blade  315 . The embodiment of the connector plate  305  illustrated in  FIGS. 3A and 3B  includes a bend  340  separating an auger connector section  310  for connection with the flighting of the auger and a blade connector section  311  for connection with the blade  315 . 
     The auger connector section  310  includes holes  325  through which fasteners, such bolts or rivets, may be used for connecting the connector plate  305  to the auger. It will be appreciated by one of ordinary skill in the art that any suitable number and orientation of holes  325  may be used for allowing the connection. Alternatively, the connector plate  305  may be welded to the auger flighting thereby alleviated the need for any holes  325 . 
     The connector section  311  includes holes  330  through which fasteners, such as bolts or rivets, may be used for connecting the blade  315  to the connector plate  305 . It will be appreciated by one of ordinary skill in the art that any suitable number and orientation of holes  330  may be used for allowing the connection. Alternatively, the connector plate  305  may be welded to the blade  315  thereby alleviated the need for any holes  330 . It will be appreciated that the method attachment is not essential to the invention and that the embodiment shown in the Figures is merely illustrative. 
     The bend  340  may be of any suitable angle to bring the blade  315  into an orientation suitable for cutting bulk material and particularly fibrous bulk material that may be clumped or bridged in the mixing chamber as a result of rotation of the auger. For example, the bend  340  may be of an angle suitable to bring the blade  315  into an orientation that is between about 15° to about 110° from the floor of the mixing chamber which is generally substantially horizontal. The bend  340  may alternatively have an angle of between about 25° and about 90°, between about 30° and about 90°, between about 30° and about 60°, of at least about 30°, of at least about 45° or alternatively may have an angle of approximately 45°. 
     Alternatively, the connector plate  305  and the blade  315  may be integrated together into a single component. 
     Another embodiment of an example of an auger  20  is shown with reference to  FIGS. 4A ,  4 B and  4 C. The auger  20  includes an auger post  200  with depending fighting  210  including a lower flight  215  and upper fighting  216  similar to the auger described with reference to  FIGS. 2A ,  2 B and  2 C. As previously described with reference to  FIG. 1 , the auger  20  includes cutting knives  240  connected along an outside edge of the fighting  210  of the auger  20  for cutting bulk material as the auger rotates. The cutting knives  240  generally have an orientation of parallel or near parallel the floor of the mixing chamber. The auger  20  includes an angled knife  300  connected along the outside of the fighting  210 . As shown in  FIGS. 4A ,  4 B and  4 C the angled knife  300  in an exploded view may be connected rearwards of the cutting knife  240 . The angled knife  300  includes a blade  315  oriented to be angled upwards relative the cutting knife  240 . Typically, the angled knife  300  has the blade  315 , as shown in  FIG. 4B  which shows the angled knife  300  in exploded view, with an angle of between about 15° to about 110° from the floor  120  which is generally substantially horizontal. The angled knife  300  may alternatively have an angle of between about 25° and about 90°, between about 30° and about 60°, at least 30°, at least 45° or alternatively may have an angle of approximately 45°. It is important that the angled knife  300  have an angle suitable for at least partially cutting into the loosened fibrous bulk material that may have bridged during rotation of the auger  20  so that the bridging is reduced or eliminated and the fibrous bulk material more easily falls to the bottom region of the auger  20  so that the cutting knives  240  are more effective in cutting the bulk material and/or the flighting  210  is effective at mixing the bulk material. 
     The angled knife  300  is shown in  FIGS. 4A ,  4 B and  4 C as being attached to the auger  20  on the upper flighting  216 . One or more additional angled knives  301  may be attached to the auger  20  to provide additional cutting of loosened bridged bulk material. The additional cutting knife  301  may be attached to the upper flighting  216  and/or the lower flighting  215  either directly or indirectly behind a cutting knife  240 . Furthermore, the additional cutting knife  301  may be a series of angled knives placed in series in proximity to each other, or, as illustrated, may be a single additional angled knife placed behind a cutting knife  240 . The additional cutting knife  301  may comprise a blade  315  oriented to be angled upwards relative the cutting knife  240 , and may be connected to the flighting  210  via a connector plate  305  as described with reference to  FIG. 3 . Typically, the additional angled knife  301  has a blade  315 , as shown in  FIG. 4B  which shows the additional angled knife  301  in exploded view, with the blade  315  having an angle of between about 15° to about 110° from the floor  120  which is generally substantially horizontal. The blade  315  of the additional angled knife  301  may alternatively have an angle of between about 25° and about 90°, between about 30° and about 60°, at least 30°, at least 45° or alternatively may have an angle of approximately 45°. It is important that the additional angled knife  301  have an angle suitable for at least partially cutting into the loosened fibrous bulk material that may have bridged during rotation of the auger  20  so that the bridging is reduced or eliminated and the fibrous bulk material more easily falls to the bottom region of the auger  20  so that the cutting knives  240  are more effective in cutting the bulk material and/or the flighting  210  is more effective at mixing the bulk material. 
     Although  FIGS. 4A ,  4 B and  4 C illustrate only a single additional angled knife  301 , it will be appreciated that a plurality of additional angled knives may be attached to the auger  20 . 
     It is also contemplated that the cutting knife  240  and the angled knife  300  may integrated together into a single knife having a curved or bent blade. 
     The vertical auger may further include various devices for directing and guiding the bulk material as it mixes, such as a slide plate mounted to the lower flight. The slide plate may be as described in either of co-pending Canadian patent applications 2,627,001 and 2,641,928 or as described below with reference to the lower cutting blade. A vertical auger of the present invention may further include or may alternatively include one or more lower cutting blades as described below for cutting trapped material away from the discharge opening thereby freeing the trapped material and allowing for quicker discharge of the mixed bulk material. 
       FIG. 5  shows an illustrative embodiment of a twin auger vertical mixer  600 . The twin auger vertical mixer  600  comprises a first vertical auger  20  and a second vertical auger  21 . Each vertical auger  20  and  21  comprises an angled knife  300  oriented for at least partially cutting away bridged fibrous bulk material thereby allowing for fibrous bulk material to be more effectively cut by the cutting knives  240  on the auger  20  and  21 . Cut and mixed bulk material is removed via the door  140  for use for example as feed, bedding, etc. 
     Test Results and Observations 
     Field testing was carried out in Alabama using a vertical mixer model JL4575 and a model JL4425 from Jay-Lor International. 
     While field testing the angled knife on vertical mixers, it was found that hay processing time was cut by 30-40%. 
     The angled knife also allowed for more hay to be processed at one time. Dry hay processing in model JL4574 increased from approximately 1500 lbs to 2000 lbs with less spillage. On model JL4425, dry hay processing capacity increased from 1200 lbs to 2000 lbs also with less spillage. 
     The auger with cutting knives and an angled knife allowed the processing of approximately 33% more hay in the same amount of time than an auger with only cutting knives was capable of processing. 
     When two angled knives were placed on the auger, hay processing capacity increased even more and shortened processing time. 
     It was observed that the angled knives help to eliminate or reduce the problem of a hay bale core not processing. 
     The angled knives cut mixing time of complete Total Hay Mix Ration (THMR) by an average of 20-25%. No apparent increase in horsepower was required. 
     It was also observed that the new knives help unloading of THMR from the machine as it appears the knives work like a kicker to push bulk material out the door at more frequent intervals, and discharge of bulk material is smoother and more consistent. 
     The angled knives were tested on 4 farms utilizing different THMR rations, with the same or similar results. 
     Lower Cutting Blade 
     Another illustrative embodiment of a vertical mixer having an auger is shown with reference to  FIG. 6 . A vertical mixer  50  has a mixing chamber  100  for receiving bulk material to be mixed. The mixing chamber  100  has an open top for receiving the bulk material, a floor  120 , and a depending wall  110  defining the mixing chamber  100 . A vertical auger  20  is situated in the mixing chamber  100  for mixing and cutting bulk material, such as straw, hay, grain, additives, etc. The mixing chamber  100  includes a door  140 , shown in the closed position, for covering a discharge opening through which mixed bulk material is discharged from the mixing chamber  100  when the door  140  is opened. The discharge opening and door  140  may be situated on the front of the mixing chamber  100  as illustrated in  FIG. 6  or may alternatively be situated at any position around the mixing chamber  100  as will be appreciated by one of ordinary skill in the art and as illustrated for example in  FIGS. 10A and 10B . 
     FIGS.  7  and  8 A- 8 C show various views of an illustrative embodiment of an auger  20  for use in the mixing chamber of a vertical mixer. The auger  20  has an auger post  200  with flighting  210  attached thereto. The flighting  210  serves to mix and/or cut bulk material during rotation of the auger  20 . Various configurations of flighting may be used to mix and/or out bulk material in the mixing chamber. For example, the flighting may contain a plurality of flights such as a lower flight  215  and upper flighting including a top flight. It will be appreciated that the auger flighting  210  may contain more than two flights and that the flighting  210  may be tapered, expanding from the top flight to the lower flight  215 . Alternatively, the flighting  210  may contain only a single flight, which for the purposes of the description, is referred to as the lower flight  215 . It will also be appreciated that the lower flight  215 , the upper flight, and any other flights described herein are typically joined as part of a connected, continuous flighting  210 , though they need not be. The lower flight  215  has an outside edge  235  representing the outside footprint of the lower flight  215  and, in the case of a tapered flighting  210 , the outside footprint of the flighting  210 . The flighting  210  may be as described in co-pending Canadian Patent Application 2,627,001, U.S. Pat. No. 5,863,122 or in U.S. Pat. No. 5,462,354, all of which are incorporated herein by reference in their entirety. 
     The lower flight  215  terminates in a leading edge  205 . The leading edge  205  may be elevated slightly above the floor  120  of the mixing chamber  100  and may be shaped to be substantially parallel to the floor. 
     The lower flight  215  may also include a flat section substantially parallel to the floor  120  of the mixing chamber  100  resulting in an increasing pitch between lower flight  215  and flighting thereabove over the span of the flat section. The flat section may be elevated slightly from the floor  120  of the mixing chamber  100  to minimize or prevent binding of bulk material between the floor  120  and the lower flight  215  of the auger  20 . The flat section may be shaped to be elevated above the floor  120  of the mixing chamber  100  at a level higher than the leading edge  205 . 
     The vertical auger  20  may further include various devices for directing and guiding the bulk material as it mixes, such as a slide plate  230 , mounted to the lower flight  215 . The slide plate  230  is typically connected to the lower flight  215  along a bottom edge  290 . The slide plate  230  further includes a top edge  285  opposite the bottom edge  290  which may or may not extend beyond the outside edge  235  of the lower flight  215  towards the inner surface of the wall  110  of the mixing chamber  100  (shown in  FIGS. 10A and 10B ). The top edge  285  of the slide plate  230  may extend outside of the footprint of the lower flight  215  and may also be substantially proximate to at least a back edge  400  of a discharge opening  410  in the wall  110  of the mixing chamber  100  when passing by the back edge of the discharge opening during rotation of the auger  20  as illustrated, for example, in  FIGS. 10A and 10B . This will be explained in further detail below. The slide plate  230  may terminate at the front end at a front corner  280  that may be proximate the front leading edge  205  of the lower flight  215 . 
     The slide plate  230  may form part of the lower flight  215  and may not be a separate connected piece. It is therefore within the scope of the auger  20  to have a slide plate  230  which is integrated into the lower flight  215  through, for example, bending, cutting, shaping, etc. 
     As outlined above, and with reference to  FIGS. 7 ,  8 A- 8 C, and  10 A- 10 B, vertical mixers tend to have difficulty discharging longer fibrous materials such as straw or hay. While discharging, some of the fibrous materials are trapped by wrapping around the back edge  400  of the discharge opening  410 . 
     It has been determined that the use of a lower cutting blade  220  mounted near the periphery of the auger  20  is successful in alleviating this problem. As the auger  20  rotates, the lower cutting blade  220  cuts away the trapped materials thereby freeing the trapped materials and allowing for quicker and proper discharge of the mixed bulk material. Typically, the lower cutting blade  220  cuts the trapped material away from the back edge  400 , most of which then falls through the discharge opening  410  onto a conveyor, if so mounted. The lower cutting blade  220  may be mounted either directly or indirectly to the lower flight  215  of the flighting  210  using any suitable manner, for example by bolting or welding the lower cutting blade  220  to the auger  20 . The lower cutting blade  220  may be mounted in such a manner as to be proximate the back edge  400  of the discharge opening  410  when passing by the discharge opening  410  during rotation of the auger  20  so that the path of lower cutting blade  220  during rotation of the auger  20  intersects with material trapped around the back edge  400  of the discharge opening  410 . Typically, material is trapped near the bottom of the back edge  400  and gradually builds up. As such, the lower cutting blade  220  may be mounted so that the path of the lower cutting blade  220  passes adjacent the back edge  400  of the discharge opening  410  and optionally the bottom area of the back edge  410  so that trapped material is cut away by the lower cutting blade  220 . 
     The lower cutting blade  220  may be attached to a slide plate  230  connected to the lower flight  215  as illustrated in  FIGS. 7 ,  8 A- 8 C and  10 A- 10 B. This can be especially effective if the slide plate  230  extends proximate the inner surface of the wall  110  of the mixing chamber  100  and is proximate the back edge  400  of the discharge opening  410  as the top edge  285  of the slide plate  230  rotates past the discharge opening  410 . In such a circumstance, the lower cutting blade  220  may be mounted near the top edge  285  of the slide plate  230 . To further increase the cutting ability of the lower cutting blade  220 , the lower cutting blade  220  may be mounted such that the transverse axis of the lower cutting blade  220  is either substantially vertical to the floor  120  of the mixing chamber  100  or substantially parallel to the wall  110  of the mixing chamber  100  at the back edge  400  of the opening  410 . 
     To further increase the cutting ability of the lower cutting blade  220 , the lower cutting blade  220  may be serrated. The serrations increase both the cutting nature of the lower cutting blade  220  and further increase durability of the lower cutting blade  220  and decrease maintenance required on the lower cutting blade  220 . The serrated area of the lower cutting blade  220  may comprise a coating to extend the life of the knife  220  by making it more durable or more corrosion resistant, such as but not limited to a galvanized coating or a tungsten carbide coating. 
     In an alternative embodiment, the lower cutting blade  220  may be mounted directly to the lower flight  215 . The lower cutting blade  220  may be mounted such that the front end of the lower cutting blade  220  is proximate the leading edge  205  of the lower flight  215 . In such an embodiment, the lower flight  215  may extend toward the wall  110  to be proximate the back edge  400  of the opening  410  when the lower cutting blade  220  passes by during rotation of the auger  20 . The lower cutting blade  220  should have a connection point in a location on the auger  20  that allows for the lower cutting blade  220  to pass through material that may be trapped on the back edge  400  of the discharge opening  410 . As outlined above, material is typically trapped in a lower region of the back edge  400  of the discharge opening  410 . 
     The lower cutting blade  220  may have a shallow angled front corner to minimize the force required to push the lower cutting blade  220  through the bulk material and through the trapped material. More horsepower and therefore more fuel is required as the force required to push the cutting knife through the bulk material increases. An angle of, for example but not limited to, between about 5 and 35 degrees may be used, however, an angle of 1 or more degrees should be sufficient to cut away at least a portion of the trapped material. An angle of 15 degrees may be used. It should be appreciated that these angles are merely illustrative examples. 
     The lower cutting blade  220  may have a flat exterior side facing the inner wall  110  of the mixing chamber  100 . The interior side of the cutting knife, opposite the exterior side, may include an angled top portion resulting in a sharpened edge on the top of the knife  220 . The angled top portion may be serrated as outlined above. The serrated edge extends the operational life of the lower cutting blade  220 . It is believed that the serrations impart a small transverse force on the bulk material thereby helping to mix the material. Placement of the lower cutting blade  220  on the slide plate  230  or the lower flight  215  can also aid in dislodging material from the wall  110  as well as from the back edge  400  of the discharge opening  410 . 
     A second lower cutting blade  225  may optionally be used on the auger  20  to further increase the ability of the auger  20  to cut away material trapped on the back edge  400  of the discharge opening  410 . The second knife  225  may have similar coatings and serrations as those described above with reference to the lower cutting blade  220 . The second lower cutting blade  225  may be connected directly or indirectly to the lower flight  215  of the auger  20  and should be connected at a second connection point in a location on the auger  20  that allows for the lower cutting blade  225  to pass through material that may be trapped on the back edge  400  of the opening  410 . The second connection point may be rearward of the first connection point on a periphery of either the lower flight  215  or near the top edge  285  of the slide plate  230 . The second lower cutting blade  225  may be connected using any suitable method such as but not limited to, bolting or welding. 
     The second lower cutting blade  225  may be as described above with regard to the first lower cutting blade  220 . The shallow angled front corner may be of the same or a different angle to that of the first lower cutting blade  220 . For example, the first cutting knife may have a shallow angled front corner at an angle of about 15 degrees and the second lower cutting blade  225  may have a shallow angled front corner at an angle of about 20 degrees. It should be appreciated that these angles are merely illustrative examples. It is within the scope of this disclosure that the cutting knives  220  and  225  may have shallow angled front corners of any suitable angle for cutting away material trapped around the back edge  400  of the discharge opening  410 . 
     Either one or both of the cutting knives  220  and  225  may be mounted at an angle such that the back end of the cutting knife, opposite the front shallow corner, tapers away from the inner surface of the wall  110  of the mixing chamber  100 . 
     In one non-limiting example, the first and second cutting knives  220  and  225  have a similar length. The length of the cutting knives  220  and  225  may be, for example but not limited to, about 17 inches. It will be understood, however, that the cutting knives  220  and  225  may be of different lengths relative each other, and may be greater or less than 17 inches in length. It is within the scope of this disclosure that the cutting knives  220  and  225  are of any length suitable for cutting away material trapped around the back edge  400  of the discharge opening  410 . 
     The lower cutting blade  220  and optionally the second lower cutting blade  225  cuts and removes trapped material from the opening  410  thereby allowing for quicker discharge of the bulk material from the mixing chamber  100 . Quicker discharge results in less energy consumption, less operating time of the auger and vertical mixer and therefore less maintenance and less wear and longer operating life cycle of the mixer  50  and auger  20 , and less man hours required for operation of the mixer  50  and therefore lower costs. 
     Removal of trapped material can also alleviate the pressure build-up on the wall  110  of the mixing chamber  100  when the auger  20  passes by the trapped material thereby reducing the stress imparted on the mixing chamber  100  and power unit as a result of the build-up of trapped material around the edge of the opening  400 . 
     Additionally, a more even discharge of the mixed bulk material is achieved as clumps of trapped material are reduced. A build-up of material is reduced as a result of reducing the amount of material trapped around the back edge  400  of the discharge opening  410 . 
     Although an auger with both one and two cutting knives has been illustrated, it is within the scope of the disclosure to use one, two or more cutting knives for removing material trapped on the discharge opening  410 . For example, a plurality of knives, such as three or more knives, may be mounted to the lower flight  215  or a slide plate  230  for cutting away trapped material. 
       FIGS. 9A to 9C  show an illustrative embodiment of an auger  20  comprising both the angled knife  300  as outlined above and a slide plate  230  with a lower cutting blade  220  and a second lower cutting blade  225  as described above. 
     A spacer device may be used to provide a supporting surface, such as a rub strip, a bearing surface, block or wear surface, or a rolling ball or wheel, for supporting the exterior region of the lower flight  215  or slide plate  230  when under load such as when the mixing chamber  100  is loading with bulk material. The loading of bulk material can cause the lower flight  215  to flex downwards, thereby angling the cutting knives  220  and/or  225  outwards toward the wall  110  of the mixing chamber  100 . If the lower flight  215  or the optional slide plate  230  is too thin, the flexing can be sufficient to cause the cutting knives  220  and/or  225  to contact the inner surface of the wall  110  thereby damaging or wearing the wall  110  and/or cutting knives  220  and  225 . The spacer device may be used to prevent or mitigate the flexing of the lower flight  215  and/or the slide plate  230 . The spacer device may be connected to the lower flight  215  or the optional slide plate  230 . The spacer device may be used to prevent the outer region of the lower flight of the auger from rubbing or contacting the floor and further the spacer device prevents the lower cutting blade from contacting or gouging the inside wall of the mixing chamber due to flexing of the lower flight when under load. 
     Test Results and Observations 
     Test 1: Discharge Time Using Auger without Lower Cutting Blades and with Lower Cutting Blades. 
       FIGS. 11A and 11B  are graphs illustrating test results for unloading a load of mixed bulk material comparing an auger with no lower cutting blades and an auger with lower cutting blades. For each test run, a mixture of two bales of similar hay were placed in the vertical mixer and mixed/cut and then discharged. Mixtures of both test runs were cut to similar lengths.  FIGS. 11A and 11B  are graphs showing the torque, speed and power of the vertical mixer, mixing the two bales of hay with the door  140  closed and discharging the mixed and cut hay with the door  140  open. In the graphs, the door was opened and discharge was started right after the speed has a large drop. For example, in  FIG. 11A  discharge began at approximately 9:48 and in  FIG. 11B  discharge began at approximately 9:30. The graph of  FIG. 11A  shows the results of a vertical mixer having an auger with no lower cutting blades while the graph of  FIG. 11B  shows the results of a vertical mixer having an auger with first and second lower cutting blades. The time for discharge using an auger without any cutting blades was about 12 minutes. The time for discharge using an auger with cutting blades was about 6 minutes 30 seconds. 
     The present invention has been described with regard to a plurality of illustrative embodiments. However, it will be apparent to persons skilled in the art that a number of variations and modifications can be made without departing from the scope of the invention as defined in the claims.