Abstract:
A grinding mechanism for a food waste disposer includes a grinding ring defining a plurality of window openings therethrough. A backing member receives the grinding ring and defines a plurality of cavities therein corresponding to the window openings. A plurality of stacked disks form a rotatable shredder plate that is situated to rotate relative to the grinding plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is a non-provisional application of U.S. Provisional Application Ser. No. 60/521,151, filed on Feb. 27, 2004, which is incorporated by reference herein. 

   BACKGROUND 
   The present disclosure relates generally to food waste disposers, and more particularly, to grinding mechanisms for food waste disposers. 
   Food waste disposers are used to comminute food scraps into particles small enough to safely pass through household drain plumbing. A conventional disposer includes a food conveying section, a motor section, and a grinding mechanism disposed between the food conveying section and the motor section. The food conveying section includes a housing that forms an inlet for receiving food waste and water. The food conveying section conveys the food waste to the grinding mechanism, and the motor section includes a motor imparting rotational movement to a motor shaft to operate the grinding mechanism. 
   The grind mechanism that accomplishes the comminution is typically composed of a rotating shredder plate with lugs and a stationary grind ring. The motor turns the rotating shredder plate and the lugs force the food waste against the grind ring where it is broken down into small pieces. Once the particles are small enough to pass out of the grinding mechanism, they are flushed out into the household plumbing. 
     FIG. 1  illustrates a typical grinding mechanism  10 . The illustrated grinding mechanism  10  includes a grinding plate  12  with swivel lugs  14  and a stationary grind ring  16 . The grinding plate  12  is mounted to the motor shaft  18 . The grind ring  16 , which includes a plurality of notches  20  defining spaced teeth  21 , is fixedly attached to an inner surface of a housing  22 . 
   In the operation of the food waste disposer, the food waste delivered by the food conveying section to the grinding mechanism  10  is forced by the swivel lugs  14  against the teeth  21  of the grind ring  16 . The edges of the teeth  21  grind the food waste into particulate matter sufficiently small to pass from above the grinding plate  12  to below the grinding plate  12  via gaps between the rotating and stationary members. Due to gravity, the particulate matter that passes through the gaps between the teeth  21  drops onto the upper end frame  24  and, along with water injected into the disposer, is discharged through a threaded discharge outlet  26 . Size control is primarily achieved through controlling the size of the gap through which the food particles must pass. 
   This type of grinding, however, is much more effective on friable materials than on fibrous materials. Long fibrous and leafy food waste particulates often have escaped the grinding and cutting process in known disposer designs, resulting in longer and larger particulates escaping to the sink trap. This creates problems such as plugged traps and plugged plumbing. Known designs that may be more effective on these types of food wastes are often too costly to mass-produce. 
   The present application addresses these shortcomings associated with the prior art. 
   SUMMARY 
   In accordance with various teachings of the present disclosure, a grinding mechanism for a food waste disposer includes a grinding ring defining a plurality of window openings therethrough. A backing member receives the grinding ring and defines a plurality of cavities therein corresponding to the window openings. In certain exemplary embodiments, the grinding ring further defines a plurality of notches therein, which may alternate with the windows around the periphery of the grinding ring. 
   In accordance with other aspects of the present disclosure, a grinding mechanism for a food waste disposer includes a plurality of disks stacked to form a rotatable shredder plate. The shredder plate is situated to rotate relative to the grinding ring. In some exemplary embodiments, at least one of the stacked disks defines teeth therein, which may lie on different planes. A support member may also be attached to at least one of the disks, and define lugs extending through openings in the disks. Moreover, in exemplary embodiments, the disks define different radiuses and/or thicknesses. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: 
       FIG. 1  is a sectional view of a prior art food waste disposer grinding mechanism. 
       FIG. 2  is a sectional side view showing portions of a food waste disposer embodying aspects of the present disclosure. 
       FIGS. 3-5  illustrate aspects of an exemplary stacked shredder plate assembly. 
       FIGS. 6 and 7  illustrate another exemplary stacked shredder plate assembly. 
       FIG. 8  is a side view conceptually illustrating portions of the embodiments shown in  FIGS. 3-7 . 
       FIG. 9  is a close up view showing part of the food waste disposer illustrated in  FIG. 2 . 
       FIGS. 10-12  illustrates exemplary stationary grind ring assemblies in accordance with aspects of the present disclosure. 
       FIGS. 13 and 14  illustrate aspects of another exemplary stacked shredder plate assembly having two stacked disks. 
       FIGS. 15 and 16  illustrate aspects of a further exemplary stacked shredder plate assembly having three stacked disks. 
       FIGS. 17 and 18  conceptually illustrate aspects of still further exemplary stacked shredder plate assemblies. 
       FIGS. 19 and 20  illustrate aspects of yet another exemplary stacked shredder plate assembly. 
   

   While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
   DETAILED DESCRIPTION 
   Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     FIG. 2  illustrates portions of an exemplary food waste disposer embodying aspects of the present invention. The food waste disposer  100  includes a food conveying section  102  and a grinding mechanism  110 , which is disposed between the food conveying section  102  and a motor section (not shown). The food conveying section  102  includes a housing that forms an inlet for receiving food waste and water. The food conveying section  102  conveys the food waste to the grinding mechanism  110 , and the motor section includes a motor imparting rotational movement to a motor shaft  118  to operate the grinding mechanism  110 . 
   The grinding mechanism  110  includes a stationary grind ring  116  that is fixedly attached to an inner surface of the housing of the grind mechanism  110 . A rotating shredder plate assembly  112  is rotated relative to the stationary grind ring  116  by the motor shaft  118  to reduce food waste delivered by the food conveying section  102  to small pieces. When the food waste is reduced to particulate matter sufficiently small, it passes from above the shredder plate assembly  112 , and along with water injected into the disposer, is discharged through a discharge outlet  128 . 
   As noted in the Background section hereof, many known grinding mechanisms for food waste disposers do not adequately handle leafy or fibrous food wastes. To better handle such waste, the shredder plate assembly  112  is made up from multiple, stacked plates or disks to provide a plurality of levels for multi-stage chopping or cutting of food waste.  FIG. 5  shows an exploded view, and  FIGS. 3 and 4  are assembled top and bottom views, respectively, of an embodiment of the shredder plate assembly  112 . The illustrated embodiment includes two stacked shredder disks  121 ,  122  and a support member  126 . In some embodiments, the support member  126  includes lugs  114  that extend upwards through openings in the disks  121 ,  122 , as well as swivel lugs  115  attached to the assembly.  FIGS. 6 and 7  illustrate a similar embodiment having tabs  127  extending upwards from the top of the upper disk  121 . 
   The disks  121 ,  122  may be made by a stamping process, which is relatively inexpensive and provides sharp corners, angles and levels for cutting the food waste. The lower disk  122  defines teeth  124  about the periphery of the disk  122  for chopping food wastes. Further, in the embodiments shown in  FIGS. 3-7 , the lower disk  122  defines a radius larger than the upper disk  121 , such that the teeth  124  extend beyond the periphery of the upper disk  121 .  FIG. 8  is a partial side view of the stacked disks  121 ,  122  showing the teeth  124  of the lower disk  122  extending beyond the upper disk  121 .  FIG. 9  is a close up view of a portion of the disposer shown in  FIG. 2 , showing this “under cutting” arrangement, in which the teeth  124  of the lower disk  122  extend below a portion of the grind ring  116 . 
   The under cutting arrangement may be especially useful in conjunction with a “pass-through” grind ring assembly that has openings extending through the grind ring  116 .  FIG. 10  shows one such a grind ring  116 . The grind ring  116  shown in  FIG. 10  defines windows  130  extending therethrough, and notches  132  that create teeth  134  on the grind ring  116 . In other embodiments, such as that shown in  FIG. 11 , only the windows  130  are defined in the ring  116 . A plurality of breaker members  117  are defined by the grinding ring  116 , extending towards the center of the ring  116  to break up food waste inside the grinding mechanism  110 . 
     FIG. 12  conceptually illustrates portions of the grinding mechanism  110  in a partial sectional view. A backing member  140  defines cavities  142  therethrough that correspond to the openings  130 ,  132  through the grinding ring  116 , creating a tunnel-like passage  144  behind the openings  130 ,  132 . Now, the food waste can be either broken against, or sheared over, the edges of the openings  130 ,  132 . Once the particles are small enough to pass completely through the openings  130 ,  132 , they enter the passage  144  behind the ring  116  and are carried from there by the water flow to the discharge. The inside surface geometry of the backing member  140  creates the passages  144  behind the window openings  130  and teeth openings  132  while supporting, orienting, and limiting rotation of the metal ring  116 . To orient and limit rotation of the ring  116 , the backing member  140  defines a key that is received by a key way  151  defined in the ring  116 . 
   The fineness of the ground waste is controlled by the size of the openings  130 ,  132  in the ring  116  as seen by the food waste. The apparent opening size is affected by the rotational speed and the trajectory of the food waste into the ring. It is believed that the fibrous materials are able to partially enter the passage  144  behind the opening  130 ,  132  and are then sheared off by the passing lug  114 . The ability to shear as well as break materials during the grinding improves the fineness on a range of materials. 
   In the embodiment illustrated in  FIGS. 10  the teeth  134  forming the openings  132  have a lower surface  135  that is generally perpendicular to the face of the tooth  134  and parallel to the plane of the rotating grinding plate  112 . The edges of these lower surfaces  135  create additional cutting surfaces, which, in conjunction with the rotating grinding plate  112 , will impart an additional shearing or cutting action to the food particles. This is particularly advantageous in further reducing the size of fibrous materials. 
   Several different configurations of stacked disks are employed in various embodiments of the shredder plate assembly  112 . In addition to the lower disk having a larger radius with teeth extending beyond the periphery of the upper disk as is shown in  FIGS. 3-8 , some alternative configurations include disks having approximately the same radius, with teeth defined in one or both of the disks.  FIGS. 13 and 14  show an assembly  112  including disks  121 ,  122  having approximately the same radius, with teeth  124  in both disks. Lugs  115  are attached to the upper disk  121 , with additional fixed lugs  114  extending up through the disks  121 ,  122  from the support member  126 . To achieve the desired cutting performance, the size of the teeth  124  may be varied, and the teeth  124  may either be in line as shown in  FIG. 13 , or off set. 
     FIGS. 15 and 16  show another embodiment having three stacked disks  121 ,  122 ,  123 , with each of the disks defining teeth  124 . In the particular embodiment shown in  FIGS. 15 and 16 , the teeth  124  of the lowest disk  123  extend beyond the periphery of the upper disks  121 ,  122 . Other exemplary alternative embodiments are conceptually shown in  FIGS. 17 and 18 . In  FIG. 17 , the upper disk  121  has a larger radius and defines teeth  124 .  FIG. 18  shows a configuration with both disks  121 ,  122  defining teeth  124  therein, with the lower disk  122  defining a larger radius. Additionally, the thickness of the various disks is varied in some embodiments. For example, in the exemplary embodiments shown in  FIGS. 3-8 , the upper disk  121  is thicker than the lower disk  122 . 
     FIG. 19  shows yet another embodiment, in which the lower disk  122  defines teeth  125  that have been bent downwards such that they do not lie on the same plane as the disk  122  itself.  FIG. 20  illustrates the assembly  112  shown in  FIG. 19  attached to the motor shaft  118  and positioned relative to the stationary grind ring  116 . These cut and bent tangs or teeth  125 , in addition to the other teeth  124 , result in cutting surfaces on a plurality of staggered planes. 
   The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.