Abstract:
A cooking apparatus including a housing having an interior which contains a heating device. A sensor is provided that is operatively connected to the heating device. The sensor having an actuated position, wherein the sensor affects a heat output generated by the heating device. A first and second cooking insert for containing the food to be cooked each being separately positionable within the housing interior. The first cooking insert actuating the sensor when positioned in the housing interior, and the second cooking insert not actuating the sensor when positioned in the housing interior.

Description:
FIELD OF INVENTION 
     The present invention relates to a cooking apparatus and specifically to a multi-purpose cooking apparatus which is capable of performing various types of cooking operations, including slow cooking and roasting. 
     BACKGROUND OF THE INVENTION 
     Roasters and slow cookers are two types of cooking devices well known in the art. Roasters typically include a covered chamber lined by a metal pan for receiving the food to be cooked. The temperature controls permit a wide range of cooking temperatures that may be set to accommodate a particular recipe. Roasters typically permit temperatures as high as 500° F. which is similar to that found in a typical kitchen oven. Roasters operate similar to a standard electric oven wherein the food is placed therein and cooked for a relatively short period of time, i.e., half an hour to two or three hours. Roasters include one or more heating elements that are capable of producing the high temperature required for roasting. Roasters typically include metal pan which hold the food. The metal pan fairly quickly and evenly distributes the heat thereby preventing the formation of localized hot spots. 
     Another type of cooking device well known in the art is a slow cooker. An example of such a device is marketed by the Assignee of this application under the trademark Crockpot®. Slow cookers typically include a stoneware or ceramic vessel for holding the food. The stoneware is typically removably insertable in a housing that contains heating elements for supplying heat to the stoneware and food. Slow cookers typically have a selector switch having a “high”, “low” and “off” setting for varying the heat setting thereby affecting the cooking time. 
     The maximum power generated by slow cookers is significantly less then that for roasters since slow cookers rely on a slow even rate of cooking. Cooking time in slow cookers range from four to several hours. The low temperature cooking permits users of the device to start a meal cooking in the morning and have it ready and properly cooked in time for dinner. Due to the slow cooking nature of the device, the contents of the stoneware need not be constantly monitored in order to prevent burning such as with a roaster. In addition, the relatively low power and even distribution of heat of the slow cooker prevents any particular hot spot on the stoneware, which could lead to thermal stresses and cracking. The stoneware acts as an insulator which is beneficial for slow cooking but is susceptible to cracking if the heat output is too high and the temperature rises too quickly. 
     Roasters and slow cookers provide two very different ways to prepare food. The roaster with its high temperature range permits cooking meals within a relatively short time while the slow cooker allows simmering type cooking over several hours. Accordingly, it is desirable to have both a roaster and slow cooker in order to accommodate a wide variety of cooking situations. However, both of these units are relatively large counter top appliances and therefore either take up a large amount of kitchen counter top space or storage space in the kitchen. This particular problem is especially acute in small kitchens where the counter top space and storage is at a premium. 
     However, roasters of the prior art are unsuitable for safely slow cooking food in stoneware due to the high power output of such devices and the temperature sensitivity of stoneware. The control circuit of roasters typically includes a thermostat which turns on a heating element until a desired temperature level is reached and then the element is shut off. The cycling on and off of the heating element is used to control the temperature. Therefore, even on relatively low temperature settings a cooking vessel is subjected to a full power high heat condition that could damage stoneware. Accordingly, roasters almost exclusively include metallic inserts that are able to quickly distribute the heat and permit uniform cooking of the contents. In contrast, stoneware, which is essentially an insulator, does not dissipate heat well and is subject to cracking when exposed to fast temperature rises and high heat levels. 
     Accordingly, it would be desirable to provide a multipurpose cooking apparatus that selectively provides the cooking characteristics of both a roaster and a slow cooker. 
     SUMMARY OF THE INVENTION 
     It is an advantage of the present invention to provide a cooking apparatus which is capable of functioning as a roaster and a slow cooker. 
     It is a further advantage that the present invention to provide a cooking apparatus having a heating device which can be selectively controlled to deliver the appropriate heat depending on the cooking function which is desired. 
     It is yet a further advantage of the present invention to provide a cooking apparatus having a switch that is actuatable by a food holding component of the cooking device such that when it is inserted therein, the proper heating profile is developed. 
     These and other advantages of the present invention may be obtained by providing a cooking apparatus including a housing having an interior which contains a heating device. A sensor is provided that is operatively connected to the heating device. The sensor having an actuated position, wherein the sensor affects a heat output generated by the heating device. A first and second cooking insert for containing the food to be cooked are each separately positionable within the housing interior. The first cooking insert actuating the sensor when positioned in the housing interior, and the second cooking insert not actuating the sensor when positioned in said interior. 
     The present invention may also provide a cooking apparatus including a housing having a base and a wall extending upwardly therefrom forming a housing interior. A heating device is positioned in the housing interior. A first and second cooking insert for holding food to be cooked is provided and each of the first and second cooking inserts is separately positionable within the housing interior. A sensor is operatively connected to the heating device. The sensor is able to detect the presence of one of the first and second inserts when positioned within the housing. The sensor affects the heat output of the heating device upon the detection of the one of the first and second inserts. 
     As more specifically described by way of the preferred embodiment herein, the inserts made of differing configurations with one of the first and second inserts actuating the sensor and the other insert not actuating the sensor. To achieve this, the housing side wall ends in an upper rim and the first insert has an outwardly extending first flange supported by the upper rim when the first insert is positioned within the housing interior. The first insert has a first body portion extending below the first flange that actuates the sensor when the first flange rests upon the rim. The second insert has a second flange extending outwardly therefrom. The second flange is supported by the housing upper rim when the second insert is positioned within the housing interior. The second insert does not actuate the sensor when positioned within the insert. The sensor includes a switch that is actuatable by one of the first and second inserts. The heating device includes a plurality of heating elements and the switch is operatively connected to one of the plurality of heating elements for interrupting power transmission thereto. 
     In addition, the first insert may include a stoneware pot and the second insert may include a metallic pan. The sensor detects the presence of the first insert within the housing and limits the maximum power output of the heating device such that the cooking apparatus functions as a slow cooker. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A and 1B are an exploded perspective view of the multipurpose cooking apparatus of the present invention showing both a metallic and stoneware cooking insert. 
     FIG. 2 is a top perspective view of the cooking apparatus of the present invention. 
     FIG. 3 is a front elevational view of the present invention having the stoneware insert placed therein with portion of the cooking apparatus cut away for clarity. 
     FIG. 4 is a side elevational view showing a partial cut away of the cooking apparatus of FIG.  3 . 
     FIG. 5 is a front elevational view of the present invention having the metallic cooking insert placed therein with a portion of the housing cut away for clarity. 
     FIG. 6 is a side elevational view with a portion of the housing cut away for clarity of the cooking apparatus of FIG.  5 . 
     FIG. 7 is a schematic view of the control circuit of the present invention. 
     FIG. 8 is a schematic view of an alternative embodiment of the control circuit of the present invention. 
     FIG. 9 is a schematic view of another alternative embodiment of the control circuit of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention provides a multi-functional cooking apparatus that is capable of safely and efficiently operating as both a roaster and a slow cooker. The invention is preferably directed to a counter top cooking apparatus having the ability to combine the functions of a roaster and a slow cooker, thereby eliminating the need for two separate appliances saving valuable kitchen counter top and storage space. 
     The preferred embodiment of the present invention is shown in FIGS. 1A-B and  2 . Generally, the cooking apparatus  10  includes a housing assembly  12 , a metallic cooking insert  14  and a stoneware or ceramic cooking insert  16  that are used to hold the food. Stoneware insert  16  is essentially a pot used for slow cooking and is preferably formed of ceramic material of the type used to form standard slow cooker inserts. Metallic insert  14  is essentially a pan used for roasting. Cooking inserts  14  and  16  are selectively removably insertable within housing assembly  12  depending on if the roaster or slow cooker function is desired. Metallic insert  14  may include a removable roasting rack  17  for supporting the food. In addition, a lid  18  is further provided to cover the contents of the cooking insert. 
     Referring additionally to FIGS. 3 and 5, housing assembly  12  preferably includes a base  20  which is parametrically bounded by an upwardly extending side wall  22  ending in a rim  24 . Base  20  and side wall  22  define a housing interior  26 . Side wall  22  may include a pair of outwardly extending handles  27  in order to submit an individual to carry the cooking apparatus  10 . Housing interior preferably includes an inner surface defined by a liner  28  that is preferably formed of a heat conductive material such as aluminum or steel. Liner  28  extends along the inner surface of side wall  22  and base  20  and is configured to receive the metallic or stoneware inserts  14  and  16 . 
     In order to heat the food contents of the cooking insert, a heating device  30  is positioned about an outer surface of liner  28 . Heating device  30  preferably includes a plurality of resistance type heating elements formed in a band wrapping around liner side wall  34 . Heating elements when supplied with power transfer heat to liner  28  side wall, which through conduction carries the heat throughout the liner. The heated liner distributes the heat about the cooking insert that is positioned within the housing. In order to protect housing side wall  22  and base  20  from the heat, side wall insulation  22   a  and bottom insulation  20   a  may be inserted in the housing. Insulation  22   a  and  20   a  may be of a fiberglass material of the type typically used in roasters. 
     When a cooking insert is positioned within the housing, the side wall of the insert is spaced relatively close to heating device  30 . If the heat output is not properly regulated, problems may occur when stoneware insert  16  is placed in housing interior  26 . The stoneware insert is particularly susceptible to fast and high concentrations of heat since it does not quickly dissipate heat. This permits localized hot spots on the stoneware that could result in localized thermal stresses and cracking. The metallic insert due to its ability to quickly conduct heat away reduces any thermal stresses caused by localized heating and therefore is suitable for fast, high heat environments. 
     In order to ensure that the appropriate heat output is developed for the different inserts, the present invention includes an insert discriminating sensor. Accordingly, the cooking apparatus of the present invention can determine which insert, stoneware  16  or metallic  14 , is placed within housing  12  and adjust the maximum permitable heat output accordingly. The sensor is activated by placement of one of the inserts into the housing such that the proper heat output range for the desired cooking method can be employed. The proper heat level is maintained for a slow cooker that relies on low even heat for slowly cooking its contents over several hours. Therefore, when stoneware insert  16  is placed within housing  12 , the maximum heat output permitted by heating device  30  is limited to prevent thermal shock and cracking of the stoneware. However, when metallic insert  14  is inserted in housing  12 , and thereby designating the roaster function, the maximum heat output is permitted to be increased in order to achieve suitable roasting temperatures. 
     In the preferred embodiment, sensor  36  detects the particular configuration of inserts  14  and  16 . That is, the stoneware insert  16  and the metallic insert  14  may be differently configured resulting in sensor  36  being actuated by one insert and not the other. Referring to FIGS. 5 and 6, metallic insert  14  is a pot-like structure having a bottom wall  38  surrounded by a side wall  40  with an annular flange  42  extending radially outward from an upper end of side wall  40 . Flange  42  is dimensioned to rest upon rim  24  of the housing side wall when insert  14  is placed within housing  12 . The distance between flange  42  and an insert bottom wall  38  is such that metallic insert bottom wall  38  is spaced a certain distance d from the bottom wall  29  of liner  28 . 
     Referring to FIGS. 3 and 4, stoneware cooking insert  16  is similarly configured to metallic insert  14  having a bottom wall  44  surrounded by an upwardly extending side wall  46  which ends in the outwardly extending annular flange  48 . When insert  16  is placed within housing  12 , flange  48  is supported by housing rim  24  and side wall  46  and bottom wall  44  extend into housing interior  26 . Stoneware insert  16 , however, preferably extends further into the housing interior  26  than metallic insert  14 . 
     In order to distinguish between the two cooking inserts  14  and  16 , sensor  36  preferably includes a cut off switch that is positioned on liner bottom wall  29  and extends upwardly there through into housing interior  26 . Sensor  36  is actuated by stoneware insert  16  as shown in FIG. 3, but not engaged by metallic insert shown in FIG. 5 due to insert  16  extending further into housing interior  26  than insert  14 . Sensor  36  may be a plunger type single pole single throw switch that is biased in the unactuated position. One particular switch that has been found to be suitable is marketed by Cutler Hammer, Inc. of Milwaukee Wis. as Type 7835 K11A. Sensor  36  may be covered by a resilient heat resistant cap  37  that protects the components of sensor  36  from contamination and the heat of the cooking insert. Sensor  36  works in conjunction with a control circuit  50  (FIG. 7) to regulate the heat output of heating device  30 . 
     It is also within the contemplation of the present invention that other types of sensors could be employed in order to distinguish between different cooking inserts. For example, a sensor that would be activated by a metal and not stoneware, such as a Hall-effect type sensor, could be used to detect the metallic insert  14 . Therefore, an unactuated sensor would indicate a stoneware insert, and an actuated sensor would indicate a metallic insert was present in the housing. With such a material detecting sensor, the configuration of the two cooking inserts  14  and  16  could be substantially the same. 
     In addition, it is further within the contemplation of the present invention that the configuration of cooking inserts  14  and  16  could be altered in a number of ways in order to have only one of the inserts activate the sensor. For example, switch  36  could be mounted on housing rim  42  and one of the inserts may include a notch (not shown) in its flange. Therefore, the insert with the notch would not activate switch  36  and the insert without a notch would actuate the sensor. 
     With regard to the preferred embodiment, in order to illustrate the effects of sensor  36  being moved into the actuated position, control circuit  50  will now be described. Referring to FIG. 7, heating device  30  includes a plurality of heating elements each of varying wattage. In the preferred embodiment there are three such heating elements  30   a ,  30   b  and  30   c  having wattage values of 225 W, 50 W and 775 W, respectively. It is understood that these numbers are to be illustrative and not limiting as the actual number of elements and wattage values could be varied in order to obtain the desired heating profile. Heating elements  30   a , and  30   b  are used in the slow cooking function, and the high-wattage heating element  30   c  is used only in the roaster function. 
     Sensor  36  may be placed in control circuit  50  such that when sensor  36  is actuated by stoneware insert  16 , the circuit to at least one of the three heating elements is electrically opened thereby preventing that element from being energized. Preferably, sensor  36  may open the circuit to the 775 W heating element  30   c . Therefore, when the stoneware insert  16  is placed within the housing  12 , only the 225 W and 50 W heating elements are capable of being energized. When sensor  36  is not actuated, such as when metallic insert  14  is placed within housing interior  26 , heating element  30   c  may be energized. 
     In an alternative embodiment (not shown), metallic insert  14  may be configured to activate a sensor and stoneware insert  16  may be configured not to actuate such a sensor when placed inside housing  12 . In this embodiment the high-wattage heating element would only be energizable when the sensor is actuated by the metallic insert placed within the housing. 
     The control circuit  50  further preferably includes a first controller in the form a user actuatable selector switch  52 . A rotary-type switch of the type manufactured by Tower Manufacturing Corp. of Providence, R.I. under the label 3000 Series has been found to provide suitable results. Selector switch  52  may include four discrete positions off, low, high and roast. A first pilot light  54  may be provided to indicate that selector switch is the high or low positions. The high and low settings are selected when the slow cooker function is desired, and the roast position is selected when the roaster function is desired. Selector switch  52  is placed with the control circuit such that it receives current directly from a power source and supplies current to heating elements  30   a ,  30   b  and  30   c  in the low, high and roast settings, respectively. Selector switch  52  is preferably located on housing side wall  22 . A first dial  56  positioned on the outside of side wall  22  may be provided to permit a user to easily actuate selector switch  52 . 
     A second controller in the form of a thermostatic switch, or thermostat  58  is also preferably included. A thermostat marketed by Sammax International Ltd. of Providence, R.I. as type AP-151 has been found to be suitable for this application. Thermostat  58  is of a type known in the art for temperature control and includes a temperature sensitive bimetallic component. In the preferred embodiment, sensor  36  is placed in the control circuit between selector switch  52  and thermostat  58 . Thermostat  58  is also operatively connected to heating element  30   c . Therefore, when sensor  36  is actuated thermostat  58  and heating element  30   c  are decoupled from power source  66 . In addition, when thermostat  58  electrically opens, such as when a set temperature is reached, current to heating element  30   c  will be terminated. Thermostat  58  further includes a second dial  64  that permits the user to set a certain temperature for roasting. When the temperature of the cooking apparatus reaches the preset level, the bi-metallic component will open the circuit thereby cutting power the 750 W element  30   c . A second pilot light  62  may be provided to indicate when the circuit is closed and current is flowing through thermostat  58 . Thermostat  58  is preferably located on housing side wall  22  and is actuated by second dial  64  positioned on the outside of side wall  22  to be accessible by a user. 
     It is also of the contemplation of the present invention to combine the selector switch and thermostat switch into one control device. In such a device, the control would start in an off position and would be moveable to a low setting and then high and then further rotatable to a particular roasting temperature. 
     With reference to FIG. 7, the operation of the preferred control circuit  50  will now be described. The input of selector switch  52  is electrically coupled to an ac power source  66 , and the output is electrically coupled to heating elements  30   a ,  30   b , and  30   c . Heating element  30   c  is a high wattage element used only for the roasting function. If the slow cooker function is desired, stoneware insert  16  may be placed within housing  12  thereby actuating sensor  36 . Upon actuation, sensor  36  electrically decouples thermostat  58  and high wattage heating element,  30   c , from power source  66 . Therefore, heating element  30   c  cannot be energized with the stoneware insert in place. Selector switch  52  may then be set to either the off, low or high power setting. In the low position, power to the 225 W heating element,  30   a , is supplied. When the switch  52  is moved to the high setting both the 225 W and 50 W heating elements,  30   a  and  30   b , are powered. The high and low power settings are suitable for use with stoneware insert  16  and provide the heating requirements for slow cooking function. 
     When the roaster function is desired, a user would rotate selector switch  52  to the “roast” setting thereby electrically coupling selector switch  52  to sensor  36  and thermostat  58 . Metallic insert  14  may then be placed within housing interior  26 . Due to the configuration of insert  14 , sensor  36  remains in its unactuated position when metallic insert  14  rests within housing  12 . In the unactuated position, sensor  36  which is normally closed completes the circuit from the power source to the 775 W element,  30   c . This arrangement permits power to be supplied to heating element  30   c  thereby providing the maximum heat output of heating device  30 . The user may then set thermostat  58  to the desired cooking temperature. When the set temperature is reached, thermostat  58  will open terminating power to heating element  30   c . When the temperature drops beyond a certain level, the temperature will close providing power again to element  30   c . This cycling on and off maintains the desired cooking temperature of the cooking apparatus  10  in a manner well known in the art. 
     An alternative control circuit  50 ′ is shown in FIG.  8 . Control circuit  50 ′ differs from that of the preferred embodiment primarily in the position within the circuit of insert detecting sensor. In this embodiment, sensor  36 ′ is preferably a single throw double pole switch electrically coupled between heating elements  30   a ,  30   b , and  30   c  and power source  66 . 
     Due to the configuration of insert  14 , sensor  36 ′ remains in its unactuated position when metallic insert  14  rests within housing  12 . In the unactuated position, sensor  36 ′ completes the circuit from the power source to the 775 W element,  30   c , and simultaneously opens a circuit disabling heating elements  30   a  and  30   b . In an unactuated or first position, only element  30   c  is electrically connected to power source  66  and capable of being energized. In this state the roasting function can be performed. When sensor  36 ′ is actuated such as by stoneware insert  16 , element  30   c  is decoupled from power source  66  and elements  30   a  and  30   b  are coupled thereto. In this state the slow cooker function can be performed. 
     Referring to FIG. 9, another alternative control circuit  50 ″ may be employed. In this embodiment, heating device  30 ′ includes three heating coils  30   a ′,  30   b ′ and  30   c ′ having a wattage of 225 W, 50 W and 500 W, respectively. A selector switch  52 ′ having an off, high and low setting is also provided. Selector switch  52 ′ is placed with control circuit  50 ″ such that it receives current passing through thermostat  58  and selectively supplies current to heating elements  30   a ′ and  30   b ′. Insert detecting sensor  36  includes a normally closed single pole single throw switch that selectively controls a circuit path to heating element  30   c ′. The user adjustable thermostat  58 , of a type described with reference to the preferred embodiment, is placed in the circuit between power source  66  and heating elements such that when it electrically opens, current to heating elements  30   a ′ and  30   b ′, and  30   c ′, will be terminated. 
     When power is supplied to control circuit  50 ″ of cooking apparatus  10 , current may flow through normally closed thermostat  58  to the input of selector switch  52 ′. When stoneware insert  16  is present in housing  12  thereby actuating sensor  36 , a circuit to the 500 W heating element is electrically opened preventing this high wattage heating element form being energized. Selector switch  52 ′ may then be set to either the off, low or high power setting. In the low position, power to the 225 W heating element is supplied. When selector switch  52 ′ is moved to the high setting both the 225 W and 50 W heating elements are powered. These power settings are suitable for use with stoneware insert  16  and provide the heating requirements for slow cooking function. In addition, the minimum temperature of thermostat  58 , i.e., the minimum temperature at which the bi-metallic thermostat element will open, is not attained even when both the 225 W and 50 W heating elements  30   a ′, and  30   b ′ are powered. Therefore, the circuit from the power source to selector switch  52 ′ is always uninterrupted when cooking apparatus  10  is used as a slow cooker. 
     When the roaster function is desired, metal insert  14  may be placed within housing interior  26 . Due to the configuration of insert  14 , sensor  36  remains in its unactuated, normally closed position when insert  14  sits within housing  12 . Therefore, a circuit from the power source to the 500 W element  30   c ′ is established. A user would rotate selector switch  52 ′ to the high setting and set thermostat  58  to the desired cooking temperature. Therefore, power will be supplied to all three heating elements providing the maximum heat output of heating device  30 ′. When the set temperature is reached, thermostat  58  will open terminating power to all heating elements  30   a ′,  30   b ′ and  30   c ′. When the temperature drops beyond a certain level, the temperature will close providing again to all the elements. This cycling on and off maintains the desired cooking temperature of the cooking apparatus  10 . 
     As will be appreciated by those skilled in the art, a wide variety of circuit and circuit components could be employed in order to ensure the benefits of the preferred embodiment, i.e., limiting the heat generated when the stoneware liner  16  is inserted in the housing and permitting full power when the metallic insert or roaster function is desired. 
     Accordingly, the present invention provides the advantages of two distinct cooking apparatuses in one multi-functional unit. A user may have the benefits of both a slow cooker and a roaster without having to purchase and store two separate units. The present invention also ensures that the appropriate heat output for each cooking function is provided. 
     Thus, while there has been described what are presently believed to be the preferred embodiments of the present invention, other and further modification and changes can be made thereto without departing from the true spirit of the invention. It is intended to include all further and other modification and changes that would come within the true scope of the invention as set forth in the claims.