BACKGROUND OF THE INVENTION Many cooking devices have been devised which provide time and labor saving benefits for aiding in the preparation of food. One low maintenance device is the slow cooker which is typically a glass, ceramic, or metal cooking vessel which is heated by a relatively low wattage heating element. The food contained within the slow cooker is heated at relatively low temperature over a relatively long period oftime.

The food contained within the slow cooker, by definition, cooks slowly and thoroughly without the need for a high degree of maintenance. However, occasional and even frequent stirring with a spoon or other utensil is required in order to keep grease or oils from separating from the rest of the food mixture, and to keep films from forming on the top of sauces and dips.

In order to stir the food inside the slow cooker, the user gains access to the food via a top lid.

A slow cooker is a relatively inefficient heating device by design. The temperature inside the cooking chamber is designed to rise slowly and be maintained at a relatively low temperature of about 80 to 100 degrees Centigrade. As a result, any heat dissipation from the cooking chamber, for example when the top lid is removed, causes a substantial disruption in the cooking cycle, until the heating element contained within the slow cooker can raise the temperature within the cooking vessel back to its normal cooking temperature.

Various improvements have been made to slow cookers in recent years to reduce the heat loss through the cooking vessel, and thereby increase the cooking efficiency. One such device is disclosed in U.S. Patent No. 4,039,777 to Baker which discloses a sheath-type heating element secured to the outer surface of the vessel to provide uniform heat throughout the cooking chamber. Another conventional heat saving device is disclosed in U.S. Patent No. 4,307,287 to Weiss, which discloses a removable cooking vessel contained within a separate housing with air space therebetween, which provides a more insulated cooking chamber.

Although the prior art focuses on various heat retention improvements through the sides of the cooking vessel, the prior art has neglected to address a solution for the substantial heat loss which occurs when the lid of the slow cooker is removed to stir the cooking food. As it is always necessary to stir the food contained in the slow cooker, a slow cooker which provides a means

for stirring the cooking food without the need to remove the top lid would greatly improve the cooking efficiency and ease of use.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned heat retention problem while also supplying a labor saving benefit by providing, generally, a slow cooker having an internal mechanical stirring device whereby food contained within the slow cooker may be stirred without the need to remove the top lid. Therefore, heat loss and labor is minimized as there is no need to remove the top lid in order to stir the cooking food.

A first embodiment of the present invention is a slow cooker comprising a housing for holding food to be cooked, a stirring mechanism positioned within the housing for stirring food contained within the housing, and a controller positioned external to the housing for controlling the stirring ofthe stirring mechanism.

A second embodiment of the present invention is directed to a stirrer for a slow cooker comprising a vertical shaft having an upper and a lower portion, the lower portion suitably sized for operative engagement with a mechanical rotating device, and an upper portion for engagement with a paddle for stirring the contents of the slow cooker.

The third embodiment of the present invention is directed to a method for stirring food in a slow cooker comprising the steps of positioning a mechanical stirrer internal to the slow cooker, providing a stirring mechanism for rotating the mechanical stirrer without the need to lift the top lid of the slow cooker, and placing food to be stirred in the slow cooker and rotating the mechanical stirrer, thereby stirring the food contained within the slow cooker.

Other details and advantages of the present invention will become apparent from the following detailed description of the presently preferred embodiments of practicing the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, preferred embodiments of the invention and preferred methods of practicing the invention are illustrated in which: Figure 1 is a slow cooker utilizing the present invention.

Figure 2 is a side elevational view of the stirrer of the present invention with the paddle removed.

Figure 3 is a cross sectional view of the stirrer taken along line III of Figure 2.

Figure 4 is an exploded view of the stirrer of Figure 2.

Figure 5 is a perspective view of the stirrer of Figure 2.

Figure 6 is a top plan view of the slow cooker with the top lid removed and the stirrer in place and the paddle removed.

Figure 7 is a cross sectional view of the slow cooker taken along line VII of Figure 6.

Figure 8 is a perspective view of the clutch mating member for operative association with the stirrer of Figure 2.

Figure 9 is a side elevational view detailing the external controller attached to the housing of the slow cooker of Figure 1.

Figure 10 is a partial cross sectional view of the slow cooker of Figure 1.

Figure 11 is a cross sectional view of the slow cooker of Figure 1.

Figure 12 is an enlarged view ofthe stirring mechanism of Figure 11.

Figure 13 is a perspective view of one embodiment of a paddle attachment to the stirrer of Figure 2.

Figure 14 is a bottom plan view ofthe paddle attachment of Figure 13.

Figure 15 is a perspective view of a second embodiment of a paddle attachment to the stirrer of Figure 2.

Figure 16 is a bottom plan view of the paddle attachment of Figure 15.

Figure 17 is a perspective view of a third embodiment of a paddle attachment to the stirrer of Figure 2.

Figure 18 is a bottom plan view of the paddle attachment of Figure 17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is described with respect to the preferred physical embodiments constructed in accordance herewith. It will be apparent to those of ordinary skill in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, the invention is not limited by the specific embodiments illustrated and described, or objects or advantages thereof, but only by the scope of the appended claims, including all equivalents thereof.

As illustrated in FIGS. 1, 10 and 11, the present invention is directed to heat and labor saving improvements for a slow cooker, generally, 20. More specifically, the present invention preferably includes an agitator, such as a stirrer 10 secured inside the slow cooker 20 and controlled via an external controller 21 for reducing the number of times the top lid 4 must be removed to gain access to the cooking food. It is contemplated that the present invention will be used in association with a conventional slow cooker for mixing food materials. No particular type of slow cooker is necessary, as the present invention may accommodate any conventional slow cooker.

The present invention preferably incorporates a stirrer 10 mounted to a cooking vessel 3 of a slow cooker 20. The slow cooker 20 preferably comprises a housing 2, a cooking vessel 3 which rests within the housing 2, and a top lid 4 which encloses the food contained inside the cooking vessel 3. The cooking vessel 3 contains the food to be cooked while the top lid 4 allows access to the cooking vessel 3 for ingredient addition and food removal without the need for

manual stirring via a stirring utensil. Preferably, the cooking vessel 3 removably engages the housing 2 for convenience in food serving and cleaning.

As shown in FIGS. 7 and 10, an open-ended cylindrical base or skirt 39 wraps around the bottom portion of the cooking vessel 3, thereby providing increased stability when the cooking vessel 3 is removed from the housing 2 and placed on a table surface. The skirt 39 extends slightly beyond the stirrer 10 so that the stirrer 10 does not scratch or mark the table surface. It is contemplated, however, that the stirrer 10 of the present invention could also be employed in a housing 2 having an integral cooking vessel (not shown), or multiple internal vessels rather than the two-piece unit as described above.

The housing 2 exterior may be constructed of any conventional material including sheet metal wraps, cast aluminum or the like, but preferably incorporates a thermoplastic exterior.

This plastic exterior allows for flexibility in the manufacturing of aesthetically pleasing designs and provides for lower external temperatures.

The cooking vessel 3 may be constructed of any convention material, for example earthenware crockery or metal, such as aluminum, but is preferably constructed of a thermoset plastic material, and more preferably thermoset polyester. Thermoset polyester has very similar characteristics to earthenware. First, thermoset polyester provides a slow and steady temperature rise during the cooking process. Second, thermoset polyester helps to insulate the food contained within the cooking vessel 3 when the vessel 3 is removed from the slow cooker housing 2 to serve the food. Compared to earthenware, however, thermoset polyester material provides increased manuf8cturing flexibility to mold various aesthetically pleasing designs, is less expensive, and is more durable.

FIGS. 2-5 and 6-7 illustrate the preferred stirrer 10 contained inside the slow cooker 20 of the present invention. It should be noted that the stirrer 10 is only a portion of the stirring mechanism 25 illustrated in FIGS. 11-12. The stirring mechanism 25, preferably includes the stirrer 10 mounted to the cooking vessel 3 and the motor assembly 23 mounted to the housing 2, with the motor assembly 23 positioned to operatively engage the stirrer 10. The stirrer 10 is preferably mounted and sealed to the bottom of the cooking vessel 3 (FIGS. 7 and 12).

As illustrated in FIG. 4, the design of the stirrer 10 may be similar to a stirrer typically found in other household appliances such as a breadmaker. Unlike the breadmaker, however, the stirrer 10 used in the slow cooker 20 of the present invention stirs intermittently or continuously for the entire cooking cycle. The shaft 5 is preferably fitted with a bearing 6 at its lower portion and a clutch shifter 7 at its base. A C-clip 27 and a washer 28 are positioned between the shaft 5 and the bearing 6 while a washer 29 and a washer wave 30 are positioned between the bearing 6 and the clutch shifter 7 as illustrated. As best shown in FIGS. 2 and 3, the shaft 5 extends slightly beyond the clutch shifter 7 which tightly engages the base of the shaft 5. The stir base 9 is then fitted over the shaft 5 covering the bearing 6. The stir base 9 includes fastening holes 14

(FIG. 4), which are preferably threaded for receipt of screws 31 for attachment to the bottom of the cooking vessel 3. Preferably, the stirrer 10 is permanently and securely attached to the cooking vessel 3 in order for the tight seal between the stirrer 10 and the cooking vessel 3 to be formed and maintained. When attached, the only visible portion of the stirrer 10 from the bottom ofthe cooking vessel 3 is the small portion ofthe lower shaft 5 which slightly extends beyond the clutch shifter 7, the clutch shifter 7, and the stir base 9. As illustrated in FIG. 7, the upper portion of the shaft 5 extends upwardly through an aperture in the cooking vessel 3. A seal 11 and a cap 12 are placed over the shaft 5 in order to tightly seal the aperture in the cooking vessel 3 to prevent leakage. The seal 11 is preferably press fitted into the bottom ofthe cooking vessel 3 and is stationary as the shaft 5 rotates. The cap 12 is also preferably stationary as it rests over the seal 11. The seal 11 includes conventional liquid seals, commonly known as "oil seals" (not shown) intemal to the seal 11 to provide a sufficiently water-tight seal as the shaft 5 rotates within the seal 11.

The upper portion of the shaft 5 includes a notched cylindrical portion 32 as best shown in FIGS. 4-5 which receives a paddle 8 (FIGS. 13-18) having a mating notch 33 in a central hub 16. The mating notch 33 allows the paddle 8 to securely engage the notched portion 32 of the shaft 5 such that rotation of the shaft 5 provides a like rotation of the paddle 8. The paddle 8 is preferably removably attached to the shaft 5 for convenience in cleaning and replacement. The relatively slow rotational speeds of the stirring mechanism 25 does not require the paddle 8 to be permanently secured to the shaft 5.

The clutch shifter 7 engages a mating clutch 17 (FIG. 8) mounted on an electric motor 18 as shown in FIG. 12. The extensions 36 of the clutch shifter 7 rest between the protrusions 37 of the mating clutch when the cooking vessel 3 is placed inside the housing 2 of the slow cooker 20. As the mating clutch 17 rotates the protrusions 37 engage the extensions 36 of the clutch shifter 7 causing the clutch shifter 7 to rotate, thereby causing a like rotation of the shaft 5.

motor 18 is preferably mounted to the bottom of the slow cooker housing 2 to stabilize the rotational forces described above.

As illustrated in FIGS. 13-18, various paddle designs are available and contemplated in order to provide proper food mixing. Although various designs are contemplated and may be utilized, several designs are particularly suited for the present invention.

As illustrated in FIGS. 13-14, the one paddle design for the stirrer 10 is substantially U- shaped. A central hub 16 connects the two L-shaped portions 40, with a "foot" 41 of each L- shaped portion 40 extending vertically upwardly from the base of the cooking vessel 3, substantially parallel to the shaft 5, when the paddle 8 engages the shaft 5. The two L-shaped portions 40 are substantially positioned at an angle of 180 degrees apart as illustrated.

Another design for the paddle 8 is illustrated in FIGS. 15-16 and includes a central shaft 17 and two asymmetric arcuate portions extending therefrom. The first arcuate portion 50 is a C-

shaped extension having two substantially perpendicular members 51 and 52 with respect to the central pole 17, and a parallel member 53 connecting the two perpendicular members outwardly from the central pole 17 such that a square-shaped aperture 54 is formed. The C-shaped portion is bent inwardly toward the page and away from the viewer as illustrated. The second arcuate member 55 is preferably a solid metal blank and is substantially the same size as the square- shaped aperture 54 of the first arcuate portion 50, but which is positioned approximately 180 degrees opposite the first arcuate member and having an opposite angle of curvature. The second arcuate portion 55 is bent outwardly from the page and toward the viewer as illustrated, with the paddle 8 taking on a serpentine-like shape when viewed from below.

Yet another design of the paddle 8 is illustrated in FIGS. 17-18 and includes a central pole 17 having a substantially square C-shaped extension 60. A diagonal portion 61 extends from an upper extension member 62 to a lower perpendicular member 63, first beginning inwardly and ending outwardly with respect to the central pole 17, as illustrated, thereby creating two triangular apertures 64. The paddle 8 may be constructed of any resilient plastic, such as polyethylene, polypropylene or polyester, or a metal. Where the paddle 8 is a metal the paddle 8 may be formed from any conventional metal process, including forming, stamping, or pouring.

The paddle 8 may be constructed of any resilient metal suitable for mixing ingredients in a mixture, such as any food-safe metal, including but not limited to, stainless steel, aluminum, or plated steel, but is preferably stainless steel. The paddle 8 is preferably tumbled to remove sharp edges and burrs.

As illustrated in FIGS. 1, 9, 11, and 12, it is contemplated that the stirring mechanism 25 will be electrically connected and controlled via a conventional automatic and programmable speed controller 21 external to the housing 2 in order to produce both a labor and energy saving result. The controller 21 provides variable speed settings 70 for selection by the user. Although any number of different speeds may be utilized, it is preferred that the ingredients in the cooking vessel 3 are stirred at a slow but constant speed of approximately 5 rpm. It is contemplated that the controller 21 may include a variety of additional settings, or may include simply a low, medium and high setting as seen in most household appliances having a rotating member, such as a fan, as shown in the drawings.

It is also contemplated that the stirrer 10 could be controlled via a manual control, for example via a crank, extending outwardly from the housing (not shown) thereby providing only energy saving results, without the labor saving benefits. It is also contemplated that the stirrer 10 could be magnetically controlled, remote controlled or controlled via an automatic timing device which does not include an external controller connected to the housing 2. The preferred heating element utilized in the slow cooker 20 of the present invention is a series of conventional rope heaters (not shown) which wrap around the cooking vessel 3 and are positioned in notches

49, as best shown in FIG. 11. The rope heaters are low wattage heating elements which provide uniform heat around the cooking vessel 3.

In operation, the automatic stirrer 10 stirs ingredients in the slow cooker 20 during the cooking process, thereby keeping grease and oils from separating from the rest of the of the food, and preventing films from forming on top of sauces and dips. The automatic stirring mechanism 25 allows stirring to be accomplished without removing the top lid 4 from the slow cooker 20, thereby decreasing the amount of heat loss from the unit while also providing time and labor saving benefits by not requiring the user to constantly monitor the cooking progress of the food contained inside.

It should be noted that the detailed description of the stirrer 10 is only one example of a possible stirrer, and that it is contemplated that both a simpler and complex design will work equally well. Also, although the stirrer 10 is illustrated as part of a mechanical stirring mechanism 25, it is contemplated that the stirring mechanism 25 may be manually driven as described above.

Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those of ordinary skill in the art without departing from the spirit and the scope of the invention as defined by the following claims, including all equivalents thereof.