GRINDING MECHANISM FOR A FOOD WASTE DISPOSER

Abstract: A grinding mechanism for a food waste disposer, the grinding mechanism being enclosed in a housing (126) of the food waste disposer. The grinding mechanism includes a shredder plate assembly (144) and a stationary shredder ring (146). The shredder plate assembly has an upper rotating plate (148) and a lower lug support plate (150). The lower lug support plate has a body portion, and shredder lugs and tumbling spikes integrally formed with the body portion. The stationary ring has a plurality of teeth and may also have diverters (190) and breakers (192).

Description: GRINDING MECHANISM FOR A FOOD WASTE DISPOSER FIELD OF THE INVENTION The present invention relates generally to food waste disposers and, more particularly, to a grinding mechanism or assembly for a food waste disposer. BACKGROUND OF THE INVENTION Although food waste disposers are widely available, manufacturers continue to optimize the grinding operation of such disposers. To perform the grinding operation, conventional disposers typically include a rotating grind plate. The rotating grind plate has grinding lugs attached to the plate. The food waste delivered to the rotating grind plate is forced by the grinding lugs against a stationary shredder ring. The stationary shredder ring has teeth that grind the food waste into particulate matter sufficiently small to pass from above the rotating plate to below the grinding plate via gaps between the teeth outside the periphery of the rotating plate. The particulate matter then passes to a discharge outlet and into the drain pipe. The fineness and speed of the grind are important considerations in designing the grinding mechanism for a disposer. A manufacturer must consider the demands of a wide variety of food waste with varying properties (i.e., soft, hard, stringy, leafy, and resilient). The types of food waste have changed over the years. Due to healthier diets, consumers tend to eat more fruits and vegetables. This results in food waste having a soft, stringy, leafy, and resilient consistency. Additionally, the modern diet increased the use of white meat. The waste from meat is typically bone. Although the bones from white meat are typically not as durable or difficult to grind than bones from red meat, the bones from white meat tend to splinter. The grinding mechanism must be adequate for all types of food waste. The type and geometry of the grinding lugs affect the fineness and speed of the grind. Grinding lugs may either be stationary (fixed lugs) or free to rotate (swivel lugs). Early food waste disposers used fixed lugs. One example of a disposer with fixed lugs is disclosed in U.S. Patent No. 4,126,210 (Brenner et al.). There, a fixed impeller or lug extends upwardly and is rigidly attached to the rotating grinding plate. The geometry of the fixed impeller or lug includes a series of steps. The steps rise inwardly toward the center of the rotating grinding plate. Another example of a disposer with fixed lugs is disclosed in U.S. Patent No. 5,340,036 (Riley), which is owned by the assignee of the present application. There, fixed impellers or lugs are used in a dry waste disposer. In one embodiment, the geometry of the fixed grinding impeller or lug is sloped where the slope rises or increases inwardly toward the center of the rotating grinding plate. In other embodiments, the geometry of the fixed grinding impeller or lug is in a z-shaped or c- shaped configuration. A further embodiment includes a flat grinding impeller or lug. Again, the impeller or lug is rigidly fixed to the rotating plate. Today, disposers typically use swivel lugs. A food waste disposer having swivel lugs is disclosed in U.S. Patent No. 6,007,006 (Engel et al.), which is owned by the assignee of the present application and incorporated herein by reference in its entirety. The disposer may be mounted in a well-known manner in the drain opening of a sink using mounting members of the type disclosed in U.S. Patent No. 3,025,007 (Weiczorek), which is owned by the assignee of the present application and also incorporated herein by reference in its entirety. As shown in FIG. 1, a conventional disposer includes an upper food conveying section, a lower motor section, and a central grinding section disposed between the food conveying section and the motor section. The food conveying section includes a housing that forms an inlet at its upper end for receiving food waste and water. The housing also forms an inlet for passing water discharged from a dishwasher (not shown). The housing has diverters that are shaped to points. The food conveying section conveys the food waste to the central grinding section. The motor section includes an induction motor imparting rotational movement to a motor shaft. The motor is enclosed within a motor housing having an upper end frame, a metal lower end frame, and a bent metal stator band extending between the upper and lower end frames. The grinding section shows a typical grinding plate with swivel lugs. The swivel lug grind system in FIG. 1 has a circular rotating plate or disc, a pair of swivel lugs, and a stationary shredder ring. The plate is mounted to the motor shaft of the motor section. The swivel lugs are fastened to the plate, but are free to rotate relative to the rotating plate. The grinding section includes a housing. The housings and are fastened to the lower end frame by a plurality of bolts. As shown in FIGS. 2 and 3, the shredder ring, which includes a plurality of spaced teeth, is fixedly attached to an inner surface of the housing. In the operation of the food waste disposer, the food waste delivered by the food conveying section to the grinding section is forced by the swivel lugs against the teeth of the shredder ring. The edges of the teeth grind the food waste into particulate matter sufficiently small to pass from above the grinding plate to below the grinding plate via gaps between the teeth outside the periphery of the plate. Due to gravity, the particulate matter that passes through the gaps between the teeth drops onto the upper end frame and, along with water injected into the disposer, is discharged through a threaded discharge outlet into a tailpipe. As shown in FIG. 1, the tailpipe may be connected to the discharge outlet by an off-the-shelf plumbing nut. There are other known ways to connect a food waste disposer to a tailpipe as explained in U.S. Patent No. 6,007,006 (Engel et al.). Although the food waste disposer in FIG. 1 operates efficiently and effectively, it has been found, through the present invention, that a fixed lug grind system can provide a finer grind by optimizing the design of the grind elements. The problem of jamming is another important consideration in designing the grinding operation. Prior food waste disposers with fixed lugs were known for jamming. Jamming occurs when hard objects such as bones or broken pieces of flatware enter the food waste disposer and get stuck between the rotating grinding elements and the stationary shredder ring. In an attempt to resist jams, the prior art tried to increase the rotational speed of the rotating grind elements or capacitor start. This required increasing the horsepower of the motor, however, and resulted in additional costs of the disposer. Additionally, to resist jams, the prior art attempted to add swivel lugs to the rotating grinding plate. Although the food waste disposer in FIG. 1 with swivel lugs reduces jams, it has been found, through the present invention, that jamming can also be reduced using fixed lugs by modifying the profile of the lugs without increasing horsepower or capacitor start. The use of swivel lugs has disadvantages. For example, swivel lugs produce a noisier grinding operation. Moreover, the use of swivel lugs creates a problem known as "stuck" lugs. This happens when a food particle (typically a bone fragment or splinter) lodges itself beneath the lug and prevents the lug from moving. A "stuck" lug can cause imbalances, resulting in further noise and a degradation of the grind performance. Additionally, when a swivel lug is "stuck," the food waste is more coarse, which can result in clogged drains. The use of swivel lugs also increases the chances of "riding." Riding occurs when food particles rotate at the same speed as the grind elements without being ground. Swivel lugs promote riding because they comply to the motion of the food particle without forcing the particle to be comminuted. The prior art has attempted to solve this problem by decreasing shredder lug height, increasing rotational speeds, and modifying the swivel lugs. Although some methods have reduced the chances of riding, the problem has not been eliminated. Thus, a need exists for a grinding assembly which has the advantages of both a fixed and rotating lug type without disadvantages of either. SUMMARY OF THE INVENTION To that end, the present invention provides a grinding mechanism or assembly for a food waste disposer, the grinding mechanism being enclosed in a housing of the food waste disposer. The grinding mechanism includes a shredder plate assembly and a stationary shredder ring. The shredder plate assembly has an upper rotating plate and a lower lug support plate. The lower lug support plate has a body portion and at least one fixed shredder lug integrally formed with the body portion. The upper rotating plate has at least one key slot for receiving the fixed shredder lug. The stationary shredder ring is fixed to the housing of the food waste disposer and has a plurality of teeth. The shredder plate assembly is mounted on a motor shaft that rotates by a motor. The fixed shredder lug forces food waste against the teeth of the stationary shredder ring to grind the food waste into particulate matter. The profile of the fixed shredder lug may include a vertical toe, a notch and a heel. The heel has a slope that decreases inwardly toward the center of the lower lug support plate. The lower lug support plate may further include at least one fixed tumbling spike integrally formed with the body portion of the lower lug support plate. The fixed tumbling spike assist in the movement of the food waste. The upper rotating plate has a key hole to receive the fixed tumbling spike. The lower lug support plate may also include a strengthening rib, positive locator, or pumping fingers. The positive locators stabilize the shredder plate assembly and transfer torque from the lower lug support plate to the upper rotating plate. The pumping fingers protrude below the lower lug support plate and may protrude the outer diameter of the lower lug support plate. The pumping fingers improve the fineness of the grind performance as well as increase pumping pressure through a discharge outlet of the food waste disposer. The upper rotating plate may also include strengthening ribs, drain holes, under- cutters or ramps. The under-cutters protrude beyond the outer diameter of the lower lug support plate and improve the fineness of the grind performance. The ramps are located on the leading edge of the slot that receives the fixed shredder lug and close the void immediately in front of the shredder lug. The stationary shredder ring may also include diverters and breakers to cause the food waste to tumble, reducing the chances of "riding." The stationary shredder ring may be assembled using a TOX® round joint. The benefit of using a TOX® round joint is that it can act as a breaker for the stationary shredder ring. The shredder plate assembly and a stationary shredder ring may be formed using stamping methods, powdered metal methods, injection molding methods, or casting methods. In another embodiment, the present invention is a food waste disposer that includes an upper food conveying section, a lower motor section and a central grinding section. The upper food conveying section has a first housing forming an inlet for receiving food waste. The lower motor section has a motor for imparting rotational movement to a motor shaft. The central grinding section is disposed between the food conveying section and the motor section. The grinding section has a second housing, a shredder plate assembly and a stationary shredder ring. The shredder plate assembly is mounted to the motor shaft and has an upper rotating plate and a lower lug support plate. The stationary shredder ring has a plurality of teeth and is attached to the second housing. The lower lug support plate has a plurality of fixed shredder lugs to force the food waste against the teeth of the stationary shredder ring to grind the food waste into particulate matter. The first housing may have a dishwasher inlet and a pair of diverters. The diverters may be rounded and/or smooth in shape and located adjacent to the dishwasher inlet. The second housing may form a discharge outlet having a threaded outer surface adapted to threadably engage a threaded inner surface of a plumbing nut to connect a tailpipe to the discharge outlet. In yet another embodiment, the present invention is a food waste disposer that includes an upper food conveying section, a lower motor section and a central grinding section. The upper food conveying section has a first housing forming an inlet for receiving food waste. The lower motor section has a motor for imparting rotational movement to a motor shaft and a motor housing that encloses the motor. The central grinding section is disposed between the food conveying section and the motor section. The grinding section has a grinding mechanism and a second housing. The grinding mechanism includes a stationary shredder ring and a shredder plate assembly. The stationary shredder ring has a plurality of teeth and is attached to the second housing. The shredder plate assembly is mounted to the motor shaft and has at least one tumbling spike and a plurality of fixed shredder lugs. The tumbling spike assists in the movement of the food waste. The fixed shredder lugs force the food waste against the teeth of the stationary shredder ring to grind the food waste into particulate matter. In a further embodiment, the present invention is a grinding mechanism for a food waste disposer that is enclosed in a housing of the food waste disposer. The grinding mechanism comprises a shredder plate assembly and a stationary shredder ring. The shredder plate assembly has at least one fixed shredder lug and at least one tumbling spike. The shredder lug has a vertical toe, a notch and a heel. The heel has a slope that decreases inwardly toward the center of the shredder plate assembly. The stationary shredder ring is fixed to the housing of the food waste disposer and has a plurality of teeth. The fixed shredder lug forces the food waste against the teeth of the stationary shredder ring to grind the food waste into particulate matter. The shredder plate assembly may be formed from stamping methods, powdered metal methods, injection molding methods, or casting methods. In still another embodiment, the present invention includes a method of manufacturing a food waste disposer that has a grinding mechanism. The grinding mechanism has a shredder plate assembly and a stationary shredder ring. The shredder plate assembly includes an upper rotating plate and a lower lug support plate. The method includes the steps of forming the upper rotating plate, forming the lower lug support plate, and assembling the shredder plate assembly from the upper rotating plate and the lower support plate. The method further includes the steps of forming a stationary shredder ring, providing an enclosure, and attaching the stationary shredder ring to the enclosure. Additionally, the method includes providing a motor for imparting rotational movement to a motor shaft and mounting the shredder plate assembly to the motor shaft. The enclosure is positioned to encompass the grinding mechanism. The step of forming the upper rotating plate and the lower lug support plate may include cold stamping the component from a sheet or strip of metal, although other methods may be used such as powdered metal methods, injection molding methods, and casting methods. The step of forming the lower lug support plate may further include the step of forming a plurality of fixed shredder lugs and tumbling spikes. The lower lug support plate may further be heat treated after the forming step. The step of forming the stationary shredder ring may include cold stamping the ring from a sheet or strip of metal, although other methods may be used such as powered metal methods, injection molding methods, and casting methods. The enclosure may include a dishwasher inlet and a plurality of diverters that are rounded and/or smooth in shape. The rounded diverters may be located adjacent to the dishwasher inlet. The above summary of the present invention is not intended to represent each embodiment, or every aspect of the present invention. This is the purpose of the figures and detailed description which follow. 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. FIG. 1 is a cross-section of a typical prior art food waste disposer. FIG. 2 is an enlarged cross-section of the central grinding section of the disposer in FIG. 1. FIG. 3 is an exploded perspective view of the disposer in FIG. 1. FIG. 4 is a cross-section of one embodiment of the present invention. FIG. 5 is an enlarged cross-section of the central grinding section of the disposer in FIG. 4. FIG. 6 is an exploded perspective view of the disposer in FIG. 4. FIG. 7 is an exploded perspective view of one embodiment of a rotating shredder plate assembly, FIG. 8 is a top view of the upper rotating plate for the shredder plate assembly in FIG. 7. FIG. 9 is a top view of the lower lug support plate for the shredder plate assembly in FIG. 7. FIG. 10 is a side view of the lower lug support plate for the shredder plate assembly in FIG. 7. FIG. 1 1 is a perspective view of one embodiment of the stationary shredder ring. FIG. 1 1 A is a side view of a tooth opening for the stationary shredder ring. FIG. 12A is a side view of the joining connection for the stationary shredder ring in FIG. 1 1 using a TOX® round joint. FIG. 12B is a top view of the joining connection for the stationary shredder ring in FIG. 1 1 using a TOX® round joint. FIG. 13 is a side view of one embodiment of the fixed shredder lug and the diverter of the stationary shredder ring. FIG. 14 is a perspective view of the inside of a portion of the housing showing diverters located adjacent to the dishwasher inlet. FIG. 15 is an exploded perspective view of another embodiment of a rotating shredder plate assembly. FIG. 16 is an exploded perspective view of a further embodiment of a rotating shredder plate assembly. FIG. 17 is an exploded perspective view of yet another embodiment of a rotating shredder plate assembly. FIG. 18 is an exploded perspective view of still another embodiment of a rotating shredder plate assembly. FIGS. 19A and 19B are perspective and side views of a further embodiment of the upper rotating plate for the rotating shredder plate assembly. While the invention is susceptible to various modifications and alternative forms, certain specific embodiments thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular forms described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DESCRIPTION OF PREFERRED EMBODIMENTS Turning to the drawings, FIG. 4 depicts a food waste disposer embodying the present invention. The disposer may be mounted in a well-known manner in the drain opening of a sink using conventional mounting members of the type disclosed in U.S. Patent No. 3,025,007 (Weiczorek). The disposer includes an upper food conveying section, a lower motor section, and a central grinding section disposed between the food conveying section and the motor section. The food conveying section includes a housing that forms an inlet at its upper end for receiving food waste and water. The housing may also form an inlet for passing water discharged from a dishwasher (not shown). The food conveying section conveys the food waste to the central grinding section. The motor section includes an induction motor imparting rotational movement to a motor shaft. The motor is enclosed within a motor housing having an upper end frame, a lower end frame, and a bent stator band extending between the upper and lower end frames. Referring to FIGS. 5 and 6, the grinding section includes a grinding mechanism or assembly having a shredder plate assembly and a stationary shredder ring. The shredder plate assembly includes an upper rotating plate and a lower lug support plate. The upper rotating plate and lower lug support plate are mounted to the motor shaft of the motor section. The grinding section also includes a housing that encompasses the grinding mechanism. The housings are fastened to the lower end frame by a plurality of bolts having self-tapping threads. The housing of the grinding section encompasses the grinding mechanism. The shredder ring, which includes a plurality of spaced teeth, is fixedly attached to an inner surface of the housing by an interference fit and is preferably composed of galvanized steel but may be made of other metallic material such as stainless steel. The shredder ring may also be made of non-metallic material such as plastic. The shredder ring may also be formed into the housing by molding or machining techniques. As shown in FIG. 14, which is an inside view of housings, ramps formed on the inside wall of the housing may also be used to enhance the interference between the shredder ring and the housing. The housing may be composed of injection-molded plastic, but may be made of metallic material such as powdered metal or steel, or by casting methods such as die-casting or investment casting. The use of injection-molded plastic allows housing to be resistant to corrosion from the shredder ring. The present invention, however, is not limited to housings made of injection-molded plastic. As seen in FIGS. 6 and 7, the upper rotating plate and lower lug support plate are engaged to form the shredder plate assembly. It is preferred that the shredder plate assembly comprise of two engaged components. This reduces the complexity of the manufacturing process and increases the integrity of the grinding mechanism. The upper rotating plate and lower support plate, alternatively, may be attached by mechanical means (such as welds or rivets) or by an adhesive known by those skilled in the art. Attaching the components reduces relative movement between the two components and minimizes the number of parts to be handled during final assembly. In another embodiment, the shredder plate assembly may comprise of a single unitary component that comprises a rotating plate, fixed grinding lugs and tumbling spikes with profiles described below. The fixed grinding lugs and tumbling spikes are mounted on the rotating plate or formed as an integral part of the rotating plate. In such a case, the unitary component may be fabricated from powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die casting or investment casting. Referring to FIGS. 7 and 8, the upper rotating plate provides a platform, or table, that holds the food waste so that the food waste may be ground. The upper rotating plate may include two strengthening ribs that are preferably disposed concentric to the periphery of the upper rotating plate. Inside the strengthening ribs, the upper rotating plate includes a plurality of drain holes. FIG. 8 shows one embodiment having four drain holes inside each strengthening rib. The upper rotating plate also has a mounting hole to mount the upper rotating plate to the motor shaft. The mounting hole is preferably in the shape of a double D to assist in transmitting the torque from the motor shaft. The upper rotating plate may also include a strengthening circle to provide further support to the mounting hole. To allow the lower lug support plate to engage the upper rotating plate, the upper rotating plate includes key slots and key holes. The upper rotating plate may be formed from a flat sheet of metal that is stamped into shape. Alternatively, the upper rotating plate may be formed by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die-casting or investment casting. The upper rotating plate preferably has a thickness ranging from about 0.040 inch to about 0.100 inch thick. In a preferred embodiment, the upper rotating plate is composed of double-sided galvanized cold-rolled steel and has a thickness of about 0.071 inch. The upper rotating plate may also be composed of other metallic material such as stainless steel, powdered metal or casting material. The upper rotating plate may also be composed of non-metallic material such as plastic. Referring to FIGS. 7, 9 and 10, in one embodiment, the lower lug support plate includes a body portion, two fixed shredder lugs, and two fixed tumbling spikes. The shredder lugs preferably have a vertical toe, a curved notch, a top, and a sloped heel. The slope of the heel decreases inwardly toward the center of the lower lug support plate. The tumbling spikes preferably have a top and downwardly slanted sides. The body portion of the lower lug support plate preferably includes a strengthening rib that runs nearly the full length of the lower lug support plate. The lower lug support plate includes a mounting hole to mount the lower lug support plate to the motor shaft. The mounting hole is preferably in the shape of a double D to assist in transmitting the torque from the motor shaft. The lower lug support plate may be formed from a flat strip or sheet of metal that is stamped into shape. Like the upper rotating plate, the lower lug support plate may also be formed by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die- casting or investment casting. The lower lug support plate preferably has a thickness ranging from about 0.090 inch to about 0.190 inch think. In a preferred embodiment, the lower lug support plate is composed of stainless steel and has a thickness of about 0.125 inch thick. The lower lug support plate, however, may be made of other metallic material such as cold-rolled steel, powdered metal or casting material. The lower lug support plate may also be composed of non-metallic material such as plastic. If stamping methods are used, the shredder lugs and tumbling spikes may be formed by folding portions of the stamped metal upward. In this way, the shredder lugs and tumbling spikes are an integral part of the lower lug support plate. After forming the shredder lugs and the tumbling spikes, the lug support plate is preferably heat treated by methods known by those skilled in the art. FIGS. 7, 9 and 10 show the preferred geometric profile and placement of the shredder lugs and tumbling spikes. The dimensions of the shredder lugs and tumbling spikes will depend on the diameter of the upper rotating plate and the outer diameter of the stationary shredder ring. The following information provides preferred dimensions assuming that the outer diameter of the rotating plate is about 5.270 inches and the outer diameter of the stationary shredder ring is about 5.453 inches. The present invention, however, is not limited to these dimensions, and those skilled in the art will recognize that the dimensions may change without departing from the spirit and scope of the present invention. The shredder lugs preferably have a height (distance between the top and the top surface of the body portion of the lower lug support plate) ranging from about 0.250 inch to about 0.750 inch. In a preferred embodiment, the height of the shredder lugs is about 0.508 inch. The height of the vertical toe preferably ranges from about 0.150 inch to about 0.750 inch. In the preferred embodiment, the height of the vertical toe is about 0.292 inch. The length of the top preferably ranges from about 0.250 inch to about 1.000 inch. In a preferred embodiment, the length of the top is about 0.412 inch. The heel preferably runs a horizontal distance between about 0.000 inch to about 0.700 inch. In a prefeπed embodiment, the heel runs a horizontal distance of 0.327 inch. The heel preferably is slanted at an angle between about 30 degrees to about 90 degrees. In a preferred embodiment, the heel is slanted at an angle of about 52.2 degrees. The proximity of the heel to the center or axis of the shredder plate assembly preferably ranges from about 1.500 inches to about 2.000 inches. In a preferred embodiment, the proximity of the heel to the inner diameter of the shredder plate assembly is about 1.737 inches. The curved notch preferably has a radius in the ranges from about 0.120 inch to about 0.400 inch. In the preferred embodiment, the curved notch has a radius of about 0.200 inch. The curved notch preferably has a horizontal distance between about 0.060 inch to about 0.250 inch. In a preferred embodiment, the heel has a horizontal distance of 0.150 inch. The thickness of the shredder lug is preferably the same as the thickness of the metal strip that formed the lower lug support plate. The tumbling spikes preferably have a height (distance between the top and the top surface of the body portion of the lower lug support plate) ranging from about 0.120 inch to about 1.000 inch. In a preferred embodiment, the height of the tumbling spikes is about 0.304 inch. The width at the bottom of the tumbling spike preferably ranges from about 0.250 inch to about 1.250 inches. In the preferred embodiment, the width of the bottom of the tumbling spike is about 0.750 inch. The proximity of the tumbling spikes to the center or axis of the shredder plate assembly preferably ranges from about 0.600 inch to about 1.500 inches. In a preferred embodiment, the proximity of the tumbling spikes to the inner diameter of the shredder plate assembly is about 0.856 inch. The angle of the tumbling spikes relative to the to the shredder lugs preferably ranges from about 90 degrees to about 180 degrees. In a preferred embodiment, the angle of the tumbling spikes relative to the to the shredder lugs is about 125 degrees. Referring to FIG. 11 , the stationary shredder ring may be formed from stamping methods, powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or casting methods such as die-casting or investment casting. When composed of stamped metal, the stationary shredder ring preferably has a thickness ranging from about 0.030 inch to about 0.090 inch thick. In a preferred embodiment, the stationary shredder ring is composed of double-sided galvanized cold-rolled steel and has a thickness of about 0.055 inch. The stationary shredder ring may also be made of other metallic material such as stainless steel. The stationary shredder ring may also be made of non-metallic material such as plastic. The stationary shredder ring has a plurality of teeth. FIG. 11A shows one embodiment of the profile of the teeth. In the preferred embodiment, the stationary shredder ring has thirty- three teeth. The teeth, however, may be provided with different shapes as required in order to cause particles of different sizes or densities to be ground. The exposed tooth height above the top surface of the rotating shredder plate preferably ranges from about 0.180 inch to about 0.350 inch. In the preferred embodiment, the exposed tooth height is about 0.246 inch. The width of the tooth opening at the top surface of the rotating shredder plate preferably ranges from about 0.125 inch to about 0.375 inch. In the preferred embodiment, the width of the tooth opening is about 0.229 inch. The tooth angle preferably ranges from 0 degrees to about 20 degrees. In the preferred embodiment, the tooth angle is about 4.86 degrees. As shown in FIG. 11, the stationary shredder ring also has diverters and louvered breakers. The diverters, along with the shredder lug, cause food waste to tumble. When food waste tumbles, it reduces the chances of "riding." As shown in FIGS. 11 and 13, the diverters are bubbled shaped. The protrusion depth of the diverters preferably ranges from about 0.090 inch to about 0.250 inch. In the preferred embodiment, the protrusion depth of the diverters is about 0.165 inch. The height of the diverters preferably ranges from about 0.250 inch to about 0.625 inch. In the preferred embodiment, the height of the diverters 190 is about 0.495 inch. The width of the diverters expands preferably from about 0.125 inch to about 0.375 inch. In the preferred embodiment, the width of the diverters expands to about 0.224 inch. FIG. 13 illustrates how the profile of the fixed shredder lug aligns with the stationary shredder ring having diverters. At least a portion of the diverter passes the fixed shredder lug in close proximity without touching. The notch of the fixed shredder lug is preferably shaped to match the contour of the diverters. The distance or gap between the diverters and the fixed shredder lug preferably ranges between about 0.030 inch to about 0.090 inch. In the preferred embodiment, the distance or gap between the diverters and the fixed shredder lug is about 0.050 inch. Referring again to FIG. 1 1, the breakers are substantially rectangular and inwardly inclined. The inclined breakers promote a spiraling effect on food waste. FIG. 5 shows a cutaway view of breakers. The protrusion depth of the breakers depends on the wall thickness of the stationary shredder ring. The depth preferably ranges from about 0.030 inch to about 0.090 inch. In the preferred embodiment, the protrusion depth of the breakers is about 0.055 inch. The width of the breakers preferably ranges from about 0.125 inch to about 0.375 inch. In the preferred embodiment, the width of the breakers is about 0.250 inch. The length of the breakers preferably ranges from about 0.250 inch to about 0.750 inch. In the preferred embodiment, the length of the breakers is about 0.375 inch. The angle of the breakers preferably ranges from about 30 degrees to about 90 degrees. In the preferred embodiment, the angle of the breakers is about 45 degrees. The diverters and breakers, however, may be provided with different shapes and number as required in order to cause particles of different sizes or densities to be ground. As indicated above, the stationary shredder ring may be formed from a flat sheet of metal. When composed of stamped metal, the stationary shredder ring may be bent to annular form. The free ends of the shredder ring may be joined at a junction by welding or a material forming process such as a TOX® round joint. A TOX® round joint from TOX® Pressotechnik L.L.C. of 4250 Weaver Parkway, Warrenville, IL is very suitable. A junction created using a TOX® round joint is shown in FIGS. 12A and 12B. The benefit of using a TOX® round joint is that the TOX® round joint may serve as one of the louvered breakers. Referring to FIGS. 4 and 14, the inside of the housing of the upper food conveying section may be modified to include a pair of diverters. The diverters are located adjacent to the dishwasher inlet and are preferably rounded and/or smooth in shape. The diverters may be formed as part of the housing. The use of diverters that are rounded and/or smooth reduces the chances of jamming. As shown in FIG. 1, existing diverters have points. In the operation of the food waste disposer, the food waste delivered by the food conveying section to the grinding section is forced by the shredder lugs on the support lug plate against the teeth of the shredder ring. The tumbling spikes assist in the grinding operation by continually moving the food waste. For example, for larger fruit rinds, the tumbling spikes assist in keeping the rind moving so that the teeth receive an opportunity to comminute the waste. The edges of the teeth grind or comminute the food waste into particulate matter sufficiently small to pass from above the shredder plate assembly to below the shredder plate assembly via gaps between the teeth outside the periphery of the upper rotating plate. Due to gravity, the particulate matter that passes through the gaps between the teeth drops onto the upper end frame and, along with water injected into the disposer via the inlet, is discharged through a discharge outlet into a tailpipe. To direct the mixture of particulate matter and water toward the discharge outlet, the upper end frame is sloped downward toward its periphery. As shown in FIGS. 5 and 6, in one embodiment, the discharge outlet is formed by the housing and has a threaded outer surface. The threaded outer surface of the discharge outlet allows the tailpipe to be connected to the discharge outlet using an off-the-shelf plumbing nut. By designing the discharge outlet to accept the standard plumbing nut, the food waste disposer is significantly easier to connect to a plumbing system in the field than existing disposers. The present invention, however, is not limited to threaded discharge outlets. There are other ways known to those skilled in the art to attach the discharge of a food waste disposer to a tailpipe. One such way is discussed in the background section of U.S. Patent 6,007,006 (Engel et al.). The upper end frame separates the grinding section from the motor. To promote concentricity of the motor shaft relative to the stator band and of the upper rotating plate relative to the shredder ring, a peripheral lip of the upper end frame is secured between the housing and the stator band. The upper end frame dissipates the heat generated by the motor, prevents particulate matter and water from contacting the motor, and directs the mixture of particulate matter and water to the discharge outlet. Referring to FIGS. 5 and 6, to align the motor shaft relative to the stator band and, at the same time, permit rotation of the motor shaft relative to the upper end frame, the upper end frame forms a central bearing pocket supporting a powdered metal spherical bearing. The spherical bearing encompasses the motor shaft and is retained in the bearing pocket by a steel bearing retainer. To evenly distribute downward loads created by the grinding mechanism onto the bearing, a thrust washer encompasses the motor shaft and is positioned immediately above the spherical bearing. A steel sleeve encompasses the motor shaft, is positioned immediately above the thrust washer, and is surrounded by a spring-loaded rubber seal. Finally, the steel sleeve is covered by a steel cap for keeping out debris. It is preferred that the housings be made of injection-molded plastic integrally formed with each other using conventional injection-molding techniques, and that the upper end frame is separately formed from the housings using conventional cold stamping techniques. U.S. Patent No. 6,007,006 (Engel et al.), which is owned by the assignee of the present application and incorporated herein by reference in its entirety, provides further information on a food waste disposer using injection-molded plastic housings and a stamped metal upper end frame. By integrating the plastic housings via injection molding and separately forming the upper end frame from stamped metal, the food waste disposer is easier and less expensive to manufacture than existing disposers. The present invention is not, however, limited to housings made of injection-molded plastic and frames made using cold stamping techniques. As indicated above, the housings may be made of powdered metal, casting material, stainless steel or other metallic material. Moreover, the upper end frame may be made of plastic, powdered metal, casting material, stainless steel or other metallic material. Referring to FIG. 15, an alternative embodiment of the shredder plate assembly is shown. The upper rotating plate and lower lug support plate are engaged to form the shredder plate assembly. Similar to the assembly in FIG. 7, the upper rotating plate and lower lug support plate may be formed by stamping methods, by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die-casting or investment casting. The upper rotating plate provides a platform, or table, that holds the food waste so that the food waste may be ground. The upper rotating plate may include two strengthening ribs. The strengthening ribs are preferably disposed concentric to the periphery of the upper rotating plate. Inside the strengthening ribs, the upper rotating plate includes a plurality of drain holes. FIG. 15 shows one embodiment having two drain holes inside each strengthening rib. The upper rotating plate also has a mounting hole to mount the upper rotating plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The upper rotating plate may also include a strengthening circle to provide further support to the mounting hole. To allow the lower lug support plate to engage the upper rotating plate, the upper rotating plate includes key slots and key holes. In this embodiment, the lower lug support plate includes a body portion, two fixed shredder lugs, two positive locators, and pumping fingers. The shredder lugs have a vertical toe, a notch, and a sloping heel. Although a curved notch experiences less jams, the embodiment in FIG. 15 illustrates that a non-curved notch may also be used, especially where the diverters are also not curved. FIG. 15 also illustrates that the sloping heel may decrease in a convex manner inwardly toward the center of the lower lug support plate. The positive locators may also be used to assist in the assembly of the grinding mechanism. The positive locators stabilize the shredder plate assembly and transfer the torque from the lower lug support plate to the upper rotating plate. The pumping fingers are protrusions on the outer diameter of the lower lug support plate. The pumping fingers are located under the upper rotating plate and create a larger frontal area relative to the direction of rotation. The larger frontal area creates an increased pumping pressure through the discharge outlet. The pumping fingers may also be lengthened to pass below the stationary shredder ring. The lengthening the pumping fingers improves the fineness of the grind performance. The lower lug support plate also includes a mounting hole to mount the lower lug support plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The lower lug support plate may also include a strengthening circle to provide further support to the mounting hole. Similar to the lower lug support plate in FIG. 7, if the lower lug support plate is formed by stamping methods, the shredder lugs and positive locators may be formed by folding portions of the stamped metal upward. Referring to FIG. 16, another embodiment of the shredder plate assembly is shown. The upper rotating plate and lower lug support plate are engaged to form the shredder plate assembly. Similar to the assembly in FIG. 7, the upper rotating plate and lower lug support plate may be formed by stamping methods, by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die-casting or investment casting. The upper rotating plate provides a platform, or table, that holds the food waste so that the food waste may be ground. The upper rotating plate may include two strengthening ribs. The strengthening ribs are preferably disposed concentric to the periphery of the upper rotating plate. Inside the strengthening ribs, the upper rotating plate includes a plurality of drain holes. FIG. 16 shows one embodiment having two drain holes inside each strengthening rib. The upper rotating plate also has a mounting hole to mount the upper rotating plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The upper rotating plate may also include a strengthening circle to provide further support to the mounting hole. To allow the lower lug support plate to engage the upper rotating plate, the upper rotating plate includes key slots and key holes. In this embodiment, the upper rotating plate also includes a plurality of under- cutters. The under-cutters are protrusions that extend beyond the outer diameter of the upper rotating plate. The under-cutters also pass below the stationary shredder ring. The use of under-cutters can improve the cutting and fineness of the grind performance. If stamping methods are used to form the upper rotating plate, the under-cutters are formed by stamping the edge of the upper rotating plate. As shown in FIG. 16, one geometry of the under-cutters may be substantially rectangular. Another geometry is shown in FIG. 18 where the under-cutters are concave. Concave under-cutters experience better resistance to jams. The lower lug support plate includes a body portion, two fixed shredder lugs, two fixed tumbling spikes, and pumping fingers. The shredder lugs have a vertical toe, a notch, a top, and a sloping heel. The shredder lugs in this embodiment differ from those shown in FIGS. 9 and 10 in that the shredder lugs have a reduced profile. Additionally, the notch is not curved. The slope of the heel decreases inwardly toward the center of the lower lug support plate. The tumbling spikes preferably have a top, slanted sides and vertical sides. The tumbling spikes in this embodiment differ from those shown in FIGS. 9 and 10 in that the tumbling spikes have an increased height and reduced width. As described above, the pumping fingers are protrusions that increase pumping pressure through the discharge outlet and improve the fineness of the grind performance. The lower lug support plate also includes a mounting hole to mount the lower lug support plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The lower lug support plate may also include a strengthening circle to provide further support to the mounting hole. Similar to the lower lug support plate in FIG. 7, if the lower lug support plate is formed by stamping methods, the shredder lug and tumbling spikes may be formed by folding portions of the stamped metal upward. Referring to FIG. 17, a further embodiment of the shredder plate assembly is shown. The upper rotating plate and lower lug support plate are engaged to form the shredder plate assembly. Similar to the assembly in FIG. 7, the upper rotating plate and lower lug support plate may be formed by stamping methods, by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die-casting or investment casting. The upper rotating plate provides a platform, or table, that holds the food waste so that the food waste may be ground. The upper rotating plate may include two strengthening ribs. The strengthening ribs are preferably disposed concentric to the periphery of the upper rotating plate. Inside the strengthening ribs, the upper rotating plate includes a plurality of drain holes. FIG. 17 shows one embodiment having two drain holes inside each strengthening rib. The upper rotating plate also has a mounting hole to mount the upper rotating plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The upper rotating plate may also include a strengthening circle to provide further support to the mounting hole. To allow the lower lug support plate to engage the upper rotating plate, the upper rotating plate includes key slots and key holes. The lower lug support plate includes a body portion, two fixed shredder lugs, two fixed tumbling spikes, and pumping fingers. The shredder lugs have a vertical toe, a notch, a top, and a sloping heel. The slope of the heel decreases inwardly toward the center of the lower lug support plate. In this embodiment, however, the horizontal run of the heel is reduced as compared to the heel shown in FIGS. 9 and 10. Moreover, the height of the shredder lugs is increased. The tumbling spikes preferably have a top and slanted sides. As described above, the pumping fingers are protrusions that increase pumping pressure through the discharge outlet and improve the fineness of the grind performance. The lower lug support plate also includes a mounting hole to mount the lower lug support plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The lower lug support plate may also include a strengthening circle to provide further support to the mounting hole. Similar to the lower lug support plate in FIG. 7, if the lower lug support plate is formed by stamping methods, the shredder lug and tumbling spikes may be formed by folding portions of the stamped metal upward. Referring to FIG. 18, an alternative embodiment of the shredder plate assembly is shown. The upper rotating plate and lower lug support plate are engaged to form the shredder plate assembly. Similar to the assembly in FIG. 7, the upper rotating plate and lower lug support plate may be formed by stamping methods, by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die-casting or investment casting. The upper rotating plate provides a platform, or table, that holds the food waste so that the food waste may be ground. The upper rotating plate may include two strengthening ribs. The strengthening ribs are preferably disposed concentric to the periphery of the upper rotating plate. Inside the strengthening ribs, the upper rotating plate includes a plurality of drain holes. FIG. 18 shows one embodiment having two drain holes inside each strengthening rib. The upper rotating plate also has a mounting hole to mount the upper rotating plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The upper rotating plate may also include a strengthening circle to provide further support to the mounting hole. To allow the lower lug support plate to engage the upper rotating plate, the upper rotating plate includes key slots and key holes. In this embodiment, the upper rotating plate also includes a plurality of concave under-cutters. The under-cutters are protrusions that extend beyond the outer diameter of the upper rotating plate. The under-cutters also pass below the stationary shredder ring. The use of under-cutters can improve the cutting and fineness of the grind performance. If stamping methods are used to form the upper rotating plate, the under-cutters are formed by stamping the edge of the upper rotating plate. The concave geometry of the under-cutters also resists jams. The lower lug support plate includes a body portion, two fixed shredder lugs, two fixed tumbling spikes, and pumping fingers. As described above, the pumping fingers are protrusions that increase pumping pressure through the discharge outlet and improve the fineness of the grind performance. The shredder lugs have a vertical toe, a notch, a top, and a slanting toe. The shredder lugs in this embodiment differ from those shown in FIGS. 9 and 10 in that the shredder lugs have a reduced profile. The slope of the slanting toe decreases inwardly toward the center of the lug support plate. The tumbling spikes have a top and slanted sides. The lower lug support plate includes a mounting hole to mount the lower lug support plate to the motor shaft. The mounting hole is in the shape of a double D to assist in transmitting the torque from the motor shaft. The lower lug support plate may also include a strengthening circle to provide further support to the mounting hole. Similar to the lower lug support plate in FIG. 7, if the lower lug support plate is formed by stamping, the shredder lug and tumbling spikes may be formed by folding portions of the stamped metal upward. Referring to FIGS. 19A and 19B, an alternative embodiment of the upper rotating plate is shown. Similar to the upper rotating plate in FIG. 7, the upper rotating plate may be formed by stamping methods, by powdered metal methods, by injection molding methods such as insert plastic injection molding or metal injection molding, or by casting methods such as die-casting or investment casting. The upper rotating plate provides a platform, or table, that holds the food waste so that the food waste may be ground. The upper rotating plate may include two strengthening ribs. The strengthening ribs are preferably disposed concentric to the periphery of the upper rotating plate. Inside the strengthening ribs, the upper rotating plate includes a plurality of drain holes. FIG. 19B shows one embodiment having four drain holes inside each strengthening rib. The upper rotating plate also has a mounting hole to mount the upper rotating plate to the motor shaft. The mounting hole is preferably in the shape of a double D to assist in transmitting the torque from the motor shaft. The upper rotating plate may also include a strengthening circle to provide further support to the mounting hole. To allow the lower lug support plate to engage the upper rotating plate, the upper rotating plate includes key slots and key holes. In this embodiment, the key slots have ramps. If stamping methods are used, a ramp is formed by bending one edge of the key slot. The ramps are located on the leading edge of the key slot. For example, the upper rotating plate in FIG. 19B rotates counter-clockwise. The ramps assist in closing the void immediately in front of the lug. The ramps help prevent jamming. While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.

Claims: CLAIMS: 1. A grinding mechanism for a food waste disposer, said grinding mechanism enclosed in a housing of the food waste disposer, said grinding mechanism comprising: a shredder plate assembly including an upper rotating plate and a lower lug support plate, said lower lug support plate having a body portion and at least one fixed shredder lug integrally formed with said body portion, said upper rotating plate having at least one key slot for receiving said at least one fixed shredder lug; a stationary shredder ring fixed to the housing of the food waste disposer, said stationary shredder ring having a plurality of teeth, said at least one fixed shredder lug capable of forcing food waste against the teeth of said stationary shredder ring to grind said food waste into particulate matter. 2. The grinding mechanism of Claim 1, wherein said lower support plate further includes at least one fixed tumbling spike integrally formed with said body portion to assist in the movement of said food waste, said upper rotating plate having at least one key hole to receive said at least one fixed tumbling spike. 3. The grinding mechanism of Claim 1, wherein said lower support plate further includes a strengthening rib. 4. The grinding mechanism of Claim 1, wherein said lower support plate further includes a plurality of positive locators integrally formed with said body portion, said upper rotating plate having a plurality of key holes to receive said plurality of positive locators. 5. The grinding mechanism of Claim 1, wherein said lower support plate further includes a plurality of pumping fingers. 6. The grinding mechanism of Claim 1, wherein said at least one shredder lug of said lower support plate includes a vertical toe, a notch and a heel, said heel having a slope, said lower support plate having a center, said slope of the heel decreasing inwardly toward the center of the lower lug support plate. 7. The grinding mechanism of Claim 1, wherein said lower support plate is made from stamped metal. 8. The grinding mechanism of Claim 1, wherein said upper rotating plate includes at least one strengthening rib and a plurality of drain holes located within said strengthening rib. 9. The grinding mechanism of Claim 1, wherein said upper rotating plate includes a plurality of under-cutters. 10. The grinding mechanism of Claim 1, wherein said upper rotating plate is made from stamped metal. 11. The grinding mechanism of Claim 1 , wherein said at least one key slot has at least one edge formed as a ramp. 12. The grinding mechanism of Claim 1, wherein said stationary shredder ring is made from stamped metal, said stationary shredder ring attached at a junction using a TOX® round joint. 13. The grinding mechanism of Claim 1, wherein said stationary shredder ring includes a plurality of diverters and a plurality of breakers. 14. A food waste disposer, comprising: an upper food conveying section including a first housing forming an inlet for receiving food waste; a lower motor section including a motor for imparting rotational movement to a motor shaft; and a central grinding section disposed between said food conveying section and said motor section, said food conveying section conveying said food waste to said grinding section, said grinding section having a second housing, a shredder plate assembly and a stationary shredder ring, said shredder plate assembly mounted to said motor shaft, said shredder plate assembly having an upper rotating plate and a lower lug support plate, said stationary shredder ring having a plurality of teeth, said stationary shredder ring attached to the second housing, said lower lug support plate having a plurality of fixed shredder lugs to force said food waste against the teeth of said stationary shredder ring to grind said food waste into particulate matter. 15. The disposer of Claim 14, wherein said lower support plate further includes a at least one tumbling spike to assist in the movement of said food waste, said upper rotating plate having at least one key hole. 16. The disposer of Claim 14, wherein said lower support plate further includes a strengthening rib. 17. The disposer of Claim 14, wherein said lower support plate further includes a plurality of positive locators, said upper rotating plate having a plurality of key holes to receive said plurality of positive locators. 18. The disposer of Claim 14, wherein said lower support plate further includes a plurality of pumping fingers. 19. The disposer of Claim 14, wherein said shredder lugs of said lower support plate includes a vertical toe, a notch and a heel, said heel having a slope, said lower support plate having a center, said slope of the heel decreasing inwardly toward the center of the lower lug support plate. 20. The disposer of Claim 14, wherein said lower support plate is made from stamped metal. 21. The disposer of Claim 14, wherein said upper rotating plate includes at least one strengthening rib and a plurality of drain holes located with said strengthening rib. 22. The disposer of Claim 14, wherein said upper rotating plate includes a plurality of under-cutters. 23. The disposer of Claim 14, wherein said upper rotating plate is made from stamped metal. 24. The disposer of Claim 14, wherein said upper rotating plate includes a plurality of key slots having more than one edge for receiving said shredder lugs, at least one edge of said key slots formed as a ramp. 25. The disposer of Claim 14, wherein said stationary shredder ring is made from stamped metal, said stationary shredder ring attached at a junction using a TOX® round joint. 26. The disposer of Claim 14, wherein said stationary shredder ring includes a plurality of diverters and a plurality of breakers. 27. The disposer of Claim 14, wherein said second housing forms a discharge outlet having a threaded outer surface adapted to threadably engage a threaded inner surface of a plumbing nut used to connect a tailpipe to said discharge outlet. 28. The disposer of Claim 14, wherein said first housing has a dishwasher inlet and a pair of substantially rounded diverters, said substantially rounded diverters located adjacent to the dishwasher inlet. 29. A food waste disposer, comprising: an upper food conveying section including a first housing forming an inlet for receiving food waste; a lower motor section including a motor for imparting rotational movement to a motor shaft, said motor section including a motor housing enclosing said motor; and a central grinding section disposed between said food conveying section and said motor section, said food conveying section conveying said food waste to said grinding section, said grinding section including a grinding mechanism, said grinding mechanism grinding said food waste into particulate matter, said grinding section including a second housing encompassing said grinding mechanism, said grinding mechanism including a stationary shredder ring and a shredder plate assembly, said stationary shredder ring having a plurality of teeth, said stationary shredder ring attached to the second housing, said shredder plate assembly mounted to said motor shaft, said shredder plate assembly having at least one tumbling spike to assist moving the food waste, said shredder plate assembly having a plurality of fixed shredder lugs to force said food waste against the teeth of said stationary shredder ring to grind said food waste into particulate matter. 30. The disposer of Claim 29, wherein said shredder plate assembly further includes a plurality of pumping fingers. 31. The disposer of Claim 29, wherein said shredder lugs of said shredder plate assembly includes a vertical toe, a notch and a heel, said heel having a slope, said shredder plate assembly having a center, said slope of the heel decreasing inwardly toward the center of the shredder plate assembly. 32. The disposer of Claim 29, wherein said shredder plate assembly includes at least one strengthening rib and a plurality of drain holes. 33. The disposer of Claim 29, wherein said shredder plate assembly includes a plurality of under-cutters. 34. The disposer of Claim 29, wherein said shredder plate assembly includes an upper rotating plate and a lower lug support plate, said shredder lugs formed as an integral part of said lower lug support plate of the shredder plate assembly. 35. The disposer of Claim 34, wherein said upper rotating plate and said lower lug support plate are made from stamped metal. 36. The disposer of Claim 29, wherein said shredder plate assembly is made from a metal casting. 37. The disposer of Claim 29, wherein said stationary shredder ring is made from stamped metal, said stationary shredder ring attached at a junction using a TOX® round joint. 38. The disposer of Claim 29, wherein said stationary shredder ring includes a plurality of diverters and a plurality of breakers. 39. The disposer of Claim 29, wherein said second housing forms a discharge outlet having a threaded outer surface adapted to threadably engage a threaded inner surface of a plumbing nut used to connect a tailpipe to said discharge outlet. 40. The disposer of Claim 29, wherein said first housing has a dishwasher inlet and a pair of substantially rounded diverters, said substantially rounded diverters located adjacent to the dishwasher inlet. 41. The disposer of Claim 29, wherein said motor housing including a stamped metal upper end frame separating said grinding mechanism from said motor, said upper end frame being separately formed from said first and second molded plastic housings. 42. The disposer of Claim 29, wherein said first and second molded plastic housings are injection-molded and are integrally formed with each other. 43. A grinding assembly for a waste disposal system, said waste disposal system including a motor for imparting rotational movement to a motor shaft, said grinding assembly comprising: a plate mounted rotatably on the motor shaft; at least one fixed grinding lug disposed on the plate; at least one spike disposed on the plate; a ring disposed at least partially above said plate; a plurality of teeth disposed on the ring, said plurality of teeth concentric with the plate; at least one diverter disposed on the ring where at least a portion of the diverter passes the fixed grinding lug in close proximity without touching. 44. The grinding assembly of Claim 43, wherein said plate includes a plurality of drain holes. 45. The grinding assembly of Claim 43, wherein said at least one shredder lug includes a vertical toe, a notch and a heel, said heel having a slope, said plate having a center, said slope of the heel decreasing inwardly toward the center of the plate. 46. A grinding mechanism for a food waste disposer, said grinding mechanism enclosed in a housing of the food waste disposer, said grinding mechanism comprising: a shredder plate assembly including at least one fixed shredder lug and at least one tumbling spike, said at least one shredder lug having a vertical toe, a notch and a heel, said heel having a slope, said shredder plate assembly having a center, said slope of the heel decreasing inwardly toward the center of the shredder plate assembly; a stationary shredder ring fixed to the housing of the food waste disposer, said stationary shredder ring having a plurality of teeth, said at least one fixed shredder lug capable of forcing food waste against the teeth of said stationary shredder ring to grind said food waste into particulate matter. 47. The grinding mechanism of Claim 46, wherein said shredder plate assembly is made from casting methods. 48. The grinding mechanism of Claim 46, wherein said stationary shredder ring is made from stamped metal, said stationary shredder ring attached at a junction using a TOX® round joint. 49. The grinding mechanism of Claim 46, wherein said stationary shredder ring includes a plurality of diverters and a plurality of breakers. 50. A method of manufacturing a food waste disposer, said food waste disposer having a grinding mechanism, said grinding mechanism including a shredder plate assembly and a stationary shredder ring, said shredder plate assembly including an upper rotating plate and a lower lug support plate, said method comprising: forming the upper rotating plate; forming the lower lug support plate; forming the stationary shredder ring; assembling the shredder plate assembly from said upper rotating plate and said lower lug support plate; providing a motor for imparting rotational movement to a motor shaft; mounting said shredder plate assembly to said motor shaft; providing an enclosure; positioning said enclosure to encompass said grinding mechanism; and attaching the stationary shredder ring to said enclosure. 51. The method of Claim 50, wherein said step of forming said upper rotating plate includes cold stamping said upper rotating plate from a sheet of metal. 52. The method of Claim 50, wherein said step of forming said lower lug support plate includes cold stamping said lower lug support plate from a strip of metal. 53. The method of Claim 50, wherein said step of forming said lower lug support plate further includes the step of forming a plurality of fixed shredder lugs. 54. The method of Claim 50, wherein said step of forming said lower lug support plate further includes the step of forming a plurality of tumbling spikes to assist in the movement of said food waste. 55. The method of Claim 50, wherein after said step of forming said lower lug support plate, heat treating said lower lug support plate. 56. The method of Claim 50, wherein said step of forming said stationary shredder ring includes cold stamping said stationary shredder ring from a sheet of metal. 57. The method of Claim 50, wherein said step of forming said stationary shredder ring includes cold stamping a plurality of teeth for said stationary shredder ring from a sheet of metal. 58. The method of Claim 50, wherein said step of forming said stationary shredder ring includes cold stamping a plurality of diverters and a plurality of breakers for said stationary shredder ring from a sheet of metal. 59. The method of Claim 50, wherein said enclosure forms a dishwasher inlet and a plurality of substantially rounded diverters, said plurality of substantially rounded diverters located adjacent to the dishwasher inlet. 60. The method of Claim 50, wherein said second plastic housing forms a discharge outlet having a threaded outer surface adapted to threadably engage a threaded inner surface of a plumbing nut used to connect a tailpipe to said discharge outlet.

Inventors: ANDERSON SCOTT W, BARKE DAVID W, BOSKE PAUL W, KOLLOCH TIMOTHY W, ANDERSON, SCOTT, W., BARKE, DAVID, W., BOSKE, PAUL, W., KOLLOCH, TIMOTHY, W.
Applicants: EMERSON ELECTRIC CO, EMERSON ELECTRIC CO.
Application year: 2001
Main classification: B02C23
IPC codes: B02C18, E03C1