Multifunctional cooking system

[0002] This application is a continuation-in-part of U.S. patent application Ser. No. 09/901789, filed Jul. 11, 2001, now U.S. Pat. No. 6,515,262, and claims the benefits provided under 35 USC §120.

[0003] 1. Field of Invention

[0004] The present invention relates to cooking appliances and, more particularly, to a multifunctional cooking system including a deep well cooker having a plurality of heating elements capable of being selectively energized to correspond to different cooking modes.

[0005] Electric cooking pots for preparing and serving hot foods are well known in the art. Such cooking pots typically include a deep well member and a heating element arranged in functional relation thereto for supplying heat. Such deep well members are often constructed of stainless steel or enameled steel for reasons of sanitation and durability. It is known that both stainless steel and enameled steel have a relatively low coefficient of heat conductivity as compared with other metals.

[0006] Applying heat only to the bottom of a deep well member, especially when constructed of stainless steel or enameled steel, can result in the upper portion of the deep well member being insufficiently heated. Thus, the food in the upper portion of the well member may become too cool for serving purposes due to the loss of heat in combination with the low rate of heat conductivity of the stainless steel or enameled steel material and the slow rate at which heat is supplied to the upper portion of the deep well member.

[0007] 2. Description of the Prior Art

[0008] Various solutions have been proposed in the prior art to solve this problem. One example of a prior art deep well cooker is disclosed in U.S. Pat. No. 4,024,377 to Henke comprising a heat sink preferably formed of aluminum or another corrosion resistant metal having a relatively high coefficient of heat conductivity, which is positioned over the deep well member from below. The heat sink member is generally U-shaped and has a bottom part parallel to and spaced from the bottom of the well member and side parts parallel to and engaging the sides of the well member in heat exchanging relation. An electric heating element is disposed in the space between the bottom of the well member and the bottom part of the U-shaped heat sink member. When the electric heater is energized, heat is supplied to the bottom of the well member by direct radiation and by radiation from the bottom part of the U-shaped member and by convection due to the air in the space occupied by the heating element. Simultaneously, however, heat also flows from the bottom part of the U-shaped member, up the side parts of the U-shaped member and into the sides of the well member. The heat supplied by conduction to the sides of the well member provides for more uniform heating of the well member while also providing for more efficient utilization of the energy supplied to the heating element.

[0009] Another example of a prior art cooking device having multiple heating elements is disclosed in U.S. Pat. No. 3,393,295 to Jepson et. al. comprising a pan with a lower electric heating element supported on its underside and a deep cover with an upper heating element supported within. A thermostatic control is connected to the lower heating element for energization thereof. When the cover is closed, an electrical connection for energizing the upper heating element is completed. The control serves thermostatically to control the energization of either element in a repeating, alternating sequence and is capable of performing the functions of a frying pan, broiler, and oven. However, this invention is not directly applicable to deep well cookers nor does it disclose a wrap-around heating element for controlling heat distribution to the upper surfaces of a deep well member within such a cooker.

[0010] Thus, the present invention has been developed to provide an alternative solution to the problem of regulating the distribution of heat to all surfaces within a deep well cooker and also to provide other functional advantages over the prior art.

[0011] Accordingly, the present invention provides a multifunctional deep well cooker that includes a bottom heating element and a wrap-around heating element, which is disposed about the deep well member for heating the sides thereof. The bottom heating element and the wrap-around heating element are interconnected by a temperature control switch for heat regulation and a function control switch for selectively energizing the desired heating elements individually or in combination to provide various different cooking modes. Thus, the present multifunctional cooker is capable of providing the user with a wide variety of cooking modes such as steaming, stir-frying, roasting, baking, or deep-frying within a single deep well cooker by selectively energizing the respective heating elements and using optional cooking accessories such as lift racks and/or frying baskets, which are applicable to a particular cooking technique.

[0012] Other features and technical advantages of the present invention will become apparent from a study of the following description and the accompanying drawings.

[0013] The novel features of the present invention are set forth in the appended claims. The invention itself, however, as well as other features and advantages thereof will be best understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures wherein:

[0014] FIG. 1A is a front elevational view of the multifunctional deep well cooker of the present invention;

[0015] FIG. 1B is a front elevation view of the multifunctional cooker in an open condition showing the positions of the wrap-around and bottom elements;

[0016] FIG. 2 is a top plan view of the multifunctional cooker showing the position of the bottom heating element;

[0017] FIG. 3 is a schematic diagram representing the electrical circuitry and components of the present multifunctional deep well cooker;

[0018] FIG. 4 is a plan view of the wire lead assembly of the heating element of the present invention;

[0019] FIG. 5A is a partial cutaway elevational view showing the details of the construction of the wrap-around heating element in a double-sided configuration;

[0020] FIG. 5B is a partial cutaway elevational view showing the details of the construction of the wrap-around heating element in a single-sided configuration;

[0021] FIG. 6 is an enlarged front elevational view showing the wrap-around heating element installed about the deep well member of the present multifunctional cooker;

[0022] FIG. 7 is a cross-sectional view of an alternative embodiment of the multifunctional cooker illustrating a bottom induction heater;

[0023] FIG. 8 is a bottom plan view taken along the section line 8—8 of FIG. 7 showing the arrangement of the induction heater and related components;

[0024] FIG. 9 is a cross-sectional view of an alternative embodiment of the multifunctional cooker illustrating a bottom hot plate heater; and

[0025] FIG. 10 is a bottom plan view taken along section line 10—10 of FIG. 9 showing the details of the bottom hot plate heater.

[0026] With further reference to the drawings, there is shown therein a preferred embodiment of a multifunctional deep well cooker in accordance with the present invention, indicated generally at 10, and illustrated in FIG. 1. The present multifunctional deep well cooker 10 is comprised of an outer housing 22 equipped with external handles 24 and feet 26. Cooker 10 is also provided with a hinged lid 28 equipped with a knob or handle 30. Lid 28 includes an odor eliminating filter assembly 15.

[0027] In the preferred embodiment the housing 22 is constructed of sheet steel or other suitable material and is provided in different exterior finishes such as powder coating, stainless steel, or plated steel with different accent finishes such as copper and bronze.

[0028] The present cooker 10 also includes an inner deep well member 36 including a peripheral flange member 36aintegrally formed thereon. The deep well member 36 resides permanently within the housing 22 such that the flange 36ais disposed about the upper edge of the housing 22 as shown in FIG. 1B. The deep well member 36 is constructed of enamel-coated steel, cast aluminum, or cast iron having different surface finishes such as a nonstick coating and/or an anodized coating.

[0029] In the preferred embodiment the present cooker 10 also includes a removable cooking well 37 as most clearly shown in FIG. 2, which is also constructed of stainless steel, enamel-coated steel, cast aluminum or other suitable material. The cooking well 37 is easily removed from the deep well member 36 for washing for the convenience of the user.

[0030] A layer of heat resistant insulating material 21 (FIGS. 7 and 9) is disposed in the air space as at 20 between the housing 22 and the deep well member 36. Numerous types of heat insulating materials having physical and chemical properties suitable for this application are commercially available. Since such heat insulating materials are well known to those skilled in the art, further detailed discussion of the same is not deemed necessary.

[0031] A temperature control switch 32 and a multi-function control switch 34 are mounted within the housing 22 to provide the various functions of the present cooker as shown in FIGS. 1A and 1B. The temperature control switch 32 and the function control switch 34 are electrically interconnected with the bottom heating element 38 and the wrap-around heating element 40 and regulate their operation as explained hereinafter in further detail.

[0032] Referring again to FIG. 2, it can be seen that the present cooker 10 is generally rectangular in the preferred embodiment. However, it will be appreciated that the cooker 10 may also be constructed in an oval, circular, or square configuration. It will be understood that the bottom heating element 38 is constructed to approximate the dimensions of the deep well member 36 and, similarly, the wrap-around heating element 40 is configured to approximate the circumference of the deep well member 36. In this manner, optimal heating of both the bottom and side wall surfaces of the deep well member 36 can be achieved at all times during operation of the present cooking system.

[0033] Referring now to FIG. 3, there is shown therein a schematic representation of the electrical circuitry and components of the present cooking system. It will be appreciated by those skilled in the art that the present cooking system is designed for use with a standard 120 Volt/60 Hz household electrical system. The temperature control circuit includes the temperature control switch 32, which is electrically connected to resistor 42, which in turn is connected to an indicator light 44 and in turn to the ceramic terminal block 46. The temperature control switch 32 is also electrically interconnected to the function control switch 34, which is capable of passing current to either bottom heater 38 or wrap-around heater 40 individually or in combination to selectively energize the heating elements depending upon the desired cooking mode. In the preferred embodiment the bottom heater 38 operates in the range of 400 to 600 watts and the wrap-around heater at a level of 600 watts. Of course these wattage ratings may vary for a given application and cooker capacity.

[0034] Although the function control switch 34 is depicted in the schematic as a conventional electromechanical switch, it will be understood that the selection of the bottom heater 38 and the wrap-around heater 40 may be accomplished by digital or other electrical controls and that the example shown is intended to be merely illustrative and not restrictive in any sense.

[0035] Referring now to FIG. 4 there is shown therein a heater lead wire assembly, indicated generally at 50, for installation on the terminal ends of the heater ribbon strands or wire 53. In the manufacturing process the terminal ends of the heater wire 53 are tightly twisted with a bundle of nickel conductors 51 to create a heat sink, which effectively insulates the heater wire 53 from the temperature controls. Further, the twisted bundle of nickel conductors 51 and heater wire 53 is covered with a fiberglass insulation sleeve 52 and further insulated by ceramic sleeves 54 and 56 to insure that the temperature controls are accurate and not influenced by their proximity to the wrap-around heater element 40. A terminal loop connector 55 is applied to the terminal end of the heater lead wire assembly 50 in a known manner for connection to terminal block 46.

[0036] Referring now to FIGS. 5A and 5B, the details of the construction of the present heater elements will be described. Each of the heater elements 38 and 40 are constructed as a layered assembly wherein a supporting mica sheet assembly, indicated generally at 70, is interposed between an interior mica insulation board 72 and an exterior mica insulation board 74.

[0037] Since the physical and chemical properties of mica insulation board are well known to those skilled in the art, further detailed discussion of these materials is not deemed necessary.

[0038] Still referring to FIGS. 5A and 5B, it will be noted that the supporting mica sheet assembly 70 is fabricated with a plurality of notches 76 and 76a,which are formed at predetermined intervals along the opposite lateral ledges thereof. During the construction process of the heater elements, the heater wire 53 is drawn across a pair of diagonally opposed notches as at 76 and 76a,wrapped in continuous revolutions around the supporting mica sheet 70, and advanced in this manner along the entire length thereof as shown by directional arrows. It will be appreciated that when constructed using the aforementioned technique, a so-called double sided heating element having heating wire 53 disposed on both sides thereof is produced.

[0039] Using an alternative construction technique shown in FIG. 5B, a so-called one-sided heater element can be produced by initially drawing the heater wire 53 across the supporting mica sheet 70 as described in the first step hereinabove. Next, the wire 53 is interlaced between adjacent notches 76 on the same lateral edge of the supporting mica sheet 70 as shown by directional arrows. Thereafter, the wire 53 is again drawn across the supporting mica sheet 70 to the next diagonally opposed notch 76aon the opposite lateral edge thereof. Next, the wire 53 is interlaced between adjacent notches 76aon the opposite lateral edge of the supporting mica sheet.

[0040] In this manner, it will be understood that a so-called one-sided heater element having at least 75% of the total amount of heater wire 53 used in its construction disposed on one surface of the supporting mica sheet 70 may be produced. Such a one-sided heater element is advantageous in reducing the radially outward deflection of heat generated by the heating elements thereby improving heating efficiency and providing a cooler outer surface in the event of user contact for safety purposes.

[0041] In both of the above described embodiments, the supporting mica sheet 70 is permanently captured between the interior and exterior insulation boards 72 and 74 and secured at periodic intervals as shown by rivets 75 or other suitable fasteners to maintain alignment of the layers.

[0042] In an assembly procedure of the present cooker 10, the wrap-around heating element 40 is secured to an outer surface of the deep well member 36 by use of an adjustable band clamp, indicated generally at 80 as shown in FIG. 6. The band clamp 80 is conducted of sheet metal such as steel in the form of an elongated belt and includes a turn buckle mechanism, indicated generally at 82, which is capable of securing the heater belt 40 about the outer periphery of the deep well member 36.

[0043] The wrap-around heating element 40 is mounted onto studs 77 which are coupled to and project from the band clamp 80 in predetermined locations. A plurality of elongated slots 79 are formed in the terminal ends of wrap-around heater element 40 so as to be positioned in alignment with studs 77. Studs 77 engage the elongated slots 79 during assembly and provide for slight differences in length and movement between the interior and exterior insulation boards 72 and 74 and supporting mica sheet 70.

[0044] It will be noted that the wrap-around heater element 40 is fabricated to a predetermined length and during assembly is positioned so as to leave a gap as at 85 corresponding to the position of the temperature and function control switches, which are subject to heat damage. In the construction process the gap 85 may be filled with fiberglass insulation, material 88 mica insulation board or other appropriate insulating materials to protect the temperature and multi-function controls.

[0045] In an alternative embodiment of the present cooker 10′, the bottom heating element comprises an induction heater, indicated generally at 100 and illustrated in FIG. 7. In this embodiment a spiral induction coil 102 as seen in FIG. 8 in the form of a flat disc is connected to a power supply (not shown) for supplying high frequency electric power to the coil 102. In this apparatus when a high-frequency current is supplied from the power supply to the coil 102, an electromagnetic field is generated. Heat for cooking is generated in the deep well member 36 as the result of the interaction between the high frequency electromagnetic field and the metallic material of the deep well member 36.

[0046] By utilizing the induction heater 100 a large amount of electric power can be supplied to the coil 102 because the coil itself does not generate heat. Further, the heating efficiency is very high because the induction coil 102 is disposed adequately close to the deep well member 36 being separated therefrom by a glass plate as at 104 (FIG. 7). In this embodiment of the present cooker 10′ an exhaust fan 106 having an electric motor 108 is provided to remove accumulated heat from the lower portion of the housing 22 as shown in FIG. 8.

[0047] A metallic heat sink structure 110 is also provided to absorb heat to protect the electrical components from potential heat damage. Since such heat sink structures are well known to those skilled in the art, further detailed discussion thereof is not deemed necessary.

[0048] The induction heater 100 embodiment is particularly advantageous for the rapid heating of cooking oils used in deep frying and/or stir-frying cooking techniques wherein quick recovery of heat lost upon loading of chilled food items into the cooking oils is desirable to prevent oil saturation.

[0049] In yet another alternative embodiment the cooker 10″ is provided with a bottom hot plate heater, indicated generally at 120, and illustrated in FIG. 9. In this embodiment a tubular heating element 121 is contained within semicircular channels 125 formed within a cast aluminum heating plate 122 as most clearly shown in FIG. 10, which is disposed in close proximity to and directly underneath the deep well member 36. It will be noted that in the preferred embodiment the heating plate 122 is constructed in a concave/convex configuration, which has been demonstrated to provide resistance to heat deformation. The concave surface 122aof the heat plate 122 is disposed upwardly adjacent the deep well member 36 as shown in FIG. 9. In an alternative embodiment the heating plate 122 may be constructed in a convex/concave configuration (not shown) such that the convex surface is disposed upwardly adjacent the deep well member 36.

[0050] It is anticipated that the present multifunctional cooking system will be utilized in combination with various cooking accessories such as lift-racks, frying baskets and/or optional serving sets, which are insertable into the cooking well 37 and utilized for various cooking modes such as steaming, stir-frying, roasting, etc.

[0051] In summary, the present invention has been developed to provide a multifunctional cooking system including a deep well cooker that includes a bottom heating element and a flexible, wrap-around heating element which is disposed about the deep well member for heating the sides thereof The bottom heating element and the wrap-around heating element are interconnected by a temperature control switch for heat regulation and a multi-function control switch for selectively energizing the desired heating elements of the system for different cooking modes.

[0052] Although not specifically illustrated in the drawings, it should be understood that additional equipment and structural components will be provided as necessary, and that all of the components described above are arranged and supported in an appropriate fashion to form a complete and operative system incorporating features of the present invention.

[0053] It is also understood that variations may be made in the present invention without departing from the scope of the invention. For example, the present multifunctional cooking system may utilize double-sided and also single-sided heater elements as disclosed herein, which may be advantageous for specific applications.

[0054] Moreover, although illustrative embodiments of the invention have been described, a latitude of modification, change, and substitution is intended in the forgoing disclosure, and in certain instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.