Patent Abstract:
A shredder assembly for a food waste disposer that includes an impact mechanism for freeing jams. The impact mechanism uses the stored energy in the rotating portion of the disposer&#39;s rotating elements to be transmitted from the rotor shaft via an impact member to a part of the rotating shredder assembly. The shredder assembly includes a rotatable shaft and an impact member fixedly attached to the shaft to rotate therewith. A shredder disk is attached to the shaft via a clutch allowing the shredder disk to slip relative to the shaft when the shredder disk jams, wherein the impact member strikes the shredder disk to transfer rotational energy to the jam.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application is a non-provisional application of U.S. Provisional Patent Application Ser. No. 60/521,437, filed on Apr. 26, 2004, which is incorporated by reference. 
   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 assembly with lugs and a stationary grind ring. The motor turns the 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. 
   Grind mechanisms that utilize a fixed lug on the rotating shredder assembly are often susceptible to jams when grinding hard food waste, such as beef bones. The use of an induction motor may contribute to the probability of experiencing a jam because of its relatively low stall torque. To reduce the occurrences of jams, swivel, or rotatable, lugs that move out of the way before a jam can occur are employed. However, with swivel lugs, the energy displaced to the food waste is less and therefore can result in compromised grind performance. 
   The present application addresses shortcomings associated with the prior art. 
   SUMMARY 
   Among other things, a grind mechanism for a food waste disposer that includes an impact mechanism for freeing jams is disclosed. The impact mechanism uses the stored energy in the disposer&#39;s rotating elements to be transmitted to the disposer&#39;s motor shaft from an impact member to a part of the rotating shredder assembly. This energy is then transmitted to the lug and to the fixed lugs and to the food waste particle that is creating the jam. The impact energy then breaks up the food waste particle, freeing the jam. 
   In accordance with certain teachings of the present disclosure, a shredder assembly for a food waste disposer includes a rotatable shaft and an impact member fixedly attached to the shaft to rotate therewith. A shredder disk is attached to the shaft via a clutch allowing the shredder disk to slip relative to the shaft when the shredder disk jams, wherein the impact member strikes the shredder disk to transfer rotational energy to the jam. In certain exemplary embodiments, the shredder disk includes a support member attached thereto, wherein the impact member strikes the support member when the shredder disk slips. 

   
     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 an exemplary food waste disposer including a grinding mechanism in accordance with the present disclosure. 
       FIGS. 2 and 3  are perspective views of a grinding mechanism embodying aspects of the present disclosure. 
       FIG. 4  is an exploded view of the grinding mechanism illustrated in  FIGS. 2 and 3 . 
       FIGS. 5 and 6  are perspective views of an alternative grinding mechanism embodying aspects of the present disclosure. 
       FIG. 7  is an exploded view of the grinding mechanism illustrated in  FIGS. 5 and 6 . 
       FIGS. 8A and 8B  are top and side views of an exemplary t-bar impact mechanism disclosed herein. 
       FIG. 9  is an exploded view of a grinding mechanism having an alternative impact mechanism. 
       FIG. 10  is an exploded view of a grinding mechanism having another alternative impact mechanism. 
       FIGS. 11-13  illustrate yet another alternative impact mechanism. 
   

   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. 1  is a sectional view illustrating portions of an exemplary food waste disposer embodying certain teachings of the present disclosure. The food waste disposer  100  includes a food conveying section  102  and a grinding mechanism  110 , which is disposed between the food conveying section and a motor section  104 . The food conveying section  102  includes an inlet for receiving food waste and water. The food waste is conveyed to the grinding mechanism  110 , and the motor section  104  includes a motor  119  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 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 passing through the food conveying section, is then discharged from the disposer. 
     FIGS. 2 and 3  are top and bottom perspective views, respectively, showing the shredder plate assembly  112  and motor shaft  118 .  FIG. 4  is an exploded view of the shredder plate assembly  112  and shaft  118 . The particular shredder plate assembly  112  illustrated in  FIGS. 2-4  includes multiple, stacked plates to provide a plurality of levels for multi-stage chopping or cutting of food waste. The illustrated embodiment includes two stacked shredder disks  121 ,  122  and a support plate  126 . Fixed lugs  114  extend upwards from the upper shredder disk  121 , as well as swivel lugs  115 , which are attached by swivel rivets  130  to the assembly  112 . 
   The lower disk  122  defines teeth  124  about the periphery of the disk  122  for chopping food wastes. Further, 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  to provide an “under cutting” arrangement, in which the lower disk  122  extends below a portion of the grind ring  116 .  FIGS. 5-7  show various views of an alternative embodiment having a single disk  121  for the rotating shredder plate. 
   As noted above in the Background section hereof, fixed lugs in general can be prone to jams with hard objects such as bones. To address this, the illustrated embodiment includes an impact member  200  that is secured directly to the shaft  118  of the motor so as to rotate with the shaft. In the exemplary illustrated embodiments, the impact member  200  comprises a “T-bar.”  FIGS. 8A and 8B  show top and side views illustrating one exemplary T-bar  200 . In certain embodiments, the shaft  118  includes a square drive portion  220  that is received by a corresponding square opening  221  extending through the impact member  200 . 
   The shredder assembly  112  is not fixedly attached to the shaft  118 , but rather, is attached such that it slips if the disposer load increases beyond some predetermined level, such as when the disposer jams. In the illustrated exemplary embodiment, the support plate  126  is captured by a series of components that create a slip clutch. This clutch allows the rotating shredder assembly  112  to turn with the shaft  118  when not under load, but when the disposer is loaded or meets with a jam, the clutch slips allowing the assembly  112 , which includes the support plate  126 , to be impacted by the T-bar  200 . Since the T-bar  200  is fixedly attached to the rotating shaft  118 , it continues to rotate with the shaft  118  when the shredder plate assembly  112  stops rotating due to the clutch slipping. The impact member  200  rotating with the shaft  118  strikes the support plate  126  of the shredder plate assembly  112 , transferring rotational energy to the jam to free the jam, or material creating the load. 
   More specifically, in the embodiment shown in  FIGS. 3-8 , the impact member  200  defines tabs  202  that extend upwardly towards the bottom of the shredder plate assembly  112 . When a jam occurs causing the clutch to slip, the tabs  202  of the rotating impact member  200  contact downwardly extending tabs  204  of the support member  126 . 
   The clutch consists of a thrust washer  210  immediately above the T-bar  200  and another thrust washer  212  immediately above the support plate  126 . A cupped spring, or Belleville, washer  214  and a cap nut  216  secure the clutch and rotating shredder assemblies  112  on the shaft  118 . The Belleville washer  214  maintains the predetermined preload so as to maintain a controlled slip point in the clutch. The thrust washers  210 ,  212  may be made of a polymeric material that is non-corrosive, non-hydroscopic and abrasion resistant. All metallic components preferably are stainless steel to avoid corrosion. The T-bar  200 , support plate  126  and the square drive portion  220  of the shaft  118  are heat treated to increase the mechanical properties to acceptable levels. 
   An impact mechanism  300  in accordance with an alternative embodiment is shown in  FIG. 9 . A rotating shredder plate assembly  312  includes a shredder disk  121  and a support plate  126 . The impact mechanism  300  includes sliding lugs  314  that are retained by rivets  316  extending through the rotating shredder assembly  312 . The rivets  316  extend through a slot  318  in the lugs  314 , through openings in the shredder disk  121 , and through spacers  320 . The impacting occurs between the rivets  316  and the lugs  314 . In essence, the lugs  314  slide concentrically to the rotating shredder assembly  312  about the lug retaining rivets  316 . 
   Another alternative embodiment is illustrated in  FIG. 10 . An impact mechanism  400  includes a cup-shaped anvil  410  secured directly to the motor shaft by a bolt  412 . The anvil  410  is situated between the shredder disk  121  and the support plate  126 . Thrust bearings  414  are positioned above and below the support plate  126 , with a thrust washer  416  below the lower thrust bearing  414 . Lugs  420  on the anvil  410  impact mating lugs  422  integral to the support plate  126  to dislodge jams. 
   Another impact mechanism shown in  FIGS. 11-13  includes a two piece anvil system. A lower anvil  450  has tabs  452  extending therefrom that are slidably received by grooves  454  in an upper anvil  456 . One of the anvil members is fixedly attached to the shaft  118  to rotate therewith, while the other anvil member is attached via the clutch so that it slips relative to the shaft upon a disposer jam. The two anvils  450 ,  456  are thus movable relative to each other, with the tabs  452  impacting the ends of the grooves  454  to dislodge jams. 
   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.

Technology Classification (CPC): 4