Abstract:
A food transfer platform incorporating a stove unit elevates to different heights, by an extendible column, and can move along a floor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/793,912 filed on Apr. 21, 2006. 

   BACKGROUND OF THE INVENTION 
   Commercial food preparation is, in effect, a manufacturing operation in which a team of skilled workers operates together to produce meals from component ingredients. Such preparation involves several major activity areas centered on appliances such as a stove, an oven, a refrigerator, a sink, and one or more preparation tables where food ingredients may be chopped or peeled or mixed or set for cooling or staging. 
   Unlike conventional manufacturing operations, much of the work in kitchens is performed manually using equipment and methods that differ only in slight degrees from those used hundreds of years ago. The work preparing food can be difficult, especially in commercial quantities, which may involve moving of large and bulky food containers that may be hot, in an environment where spills and moisture are inevitable. Mixing and cutting large quantities of food can involve repetitive manual activities that may promote repetitive motion injuries. 
   The variety and range of tasks undertaken in a commercial kitchen nevertheless require great flexibility in the equipment. Space is normally at a premium and specialized equipment that may be appropriate in a manufacturing environment may be commercially impractical in a commercial kitchen operating in a highly competitive environment. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention provides a novel new appliance for use in commercial and other kitchens providing a mobile stove unit including a food transfer platform. Motorized columns allow change in height of the food transfer platform and stove-top, allowing the mobile stove unit to be used for transferring heavy or bulky items in the kitchen environment. The stove unit also allows the appliance to be used as a conventional stove, eliminating the need for space that would be required for two separate devices. In addition to height adjustment, the invention allows conventional mixing or food preparation activities to take place at an appropriate height for a range of individuals so as to reduce repetitive motion injuries. 
   Specifically, then, the present invention comprises a kitchen appliance having a base with a plurality of downwardly extending wheels, to engage the floor and allow the base to move across a floor and providing a food transfer platform, sized to allow food preparation. The food transfer platform holds least one heating element for cooking, supported by the top of the food transfer platform. The appliance further has an extendible column that has a motor to adjust the height. The column is extendible by using a control panel providing electrical switches to control the motor. The appliance is powered by a power cord having an electrical plug to engage an electrical outlet and provide energy to at least one heating element. 
   It is thus one aspect of one embodiment of the invention that it provides a stove unit that can be used for preparation and transfer of food items in a kitchen. 
   In one embodiment of the invention, the column is extendible by more than 12 inches. This allows the cooking and food transfer platform to extend between about 27 inches and about 42 inches. 
   It is one aspect of one embodiment of the invention to cover the proper working height for up to 90 percent of the population for a variety of cooking tasks. This aspect of the invention allows the food transfer platform to move up and down to accommodate different areas of the kitchen. For example, a user may move the stove over to the refrigerator, adjust the height of the food transfer platform to equal the height of the refrigerator shelf and slide a heavy pot from the refrigerator to the food transfer platform, eliminating the need for picking up the pot and carrying it. The user could then move the appliance to a different area and adjust the food transfer platform to a height suitable for that particular user&#39;s needs. 
   In one embodiment, the heating element is an electrical resistance heater. This allows an electrical heating element to evenly distribute heat for cooking, sautéing, or keeping food warm. 
   It is one aspect of one embodiment of the invention to provide a simple and familiar stove unit. 
   In one embodiment, the heating element is alternatively an induction heater. An induction heater only warms the pot or pan on the heater, but when an induction heater is turned off, the heating element is immediately cool to the touch. 
   It is one aspect of one embodiment of the invention to allow the appliance to easily transfer from cooking use to food preparation use. 
   The invention may further include a set of upwardly extending glide rails affixed to the top of the food transfer platform. 
   It is one aspect of one embodiment of the invention to facilitate the transfer of heavy pots and the like to allow easy motion in a parallel direction to the rails, but difficulty to slide objects in a perpendicular direction to the rails. The guide rails may corral pots and pans when the user is moving the height-adjustable appliance from one area to another. 
   The appliance may further include at least one sensor that perceives an adjacent surface and communicates with the control panel and motor to adjust the height of the food transfer platform to a height of an adjacent surface. 
   Thus it is another aspect of at least one embodiment of the invention to automatically adjust to the height of an adjacent surface. Such a feature allows a user to be able to slide a heavy stockpot from a standard counter to the invention&#39;s food transfer platform, without needing to pick up the pot and risk injury. 
   More particularly, the appliance may include a sensor that may read particular encoded signals from infrared transmitters on adjacent work surfaces to automatically change the height to be compatible with those work surfaces. 
   The appliance may further include, on the periphery of the food transfer platform, along its vertical surface, pressure-sensitive switches and/or sensors, such as infrared or ultrasonic sensors that may sense the proximity or contact of the edge of the food transfer platform and other surfaces. 
   It is thus another aspect of one embodiment of the invention to reduce the possibility of finger pinching when the food transfer platform is raised or lowered. 
   The invention may further include at least one brake affixed to the wheels. 
   It is an aspect of one embodiment to allow a user to secure the height-adjustable appliance in place during cooking or food preparation. 
   The brake may be electromechanical and may communicate with the control panel, such that the brake locks in place if the heating element is in use. 
   It is therefore another aspect of at least one embodiment of the invention to prevent moving the appliance while it is being used to cook food. 
   The electromechanical brake may communicate with the power cord such that the brake locks in place when the power cord is engaged with an electrical outlet. 
   It is thus another aspect of an embodiment of the invention to prevent a user from inadvertently attempting to move the height-adjustable appliance when it is still plugged into an electrical outlet. 
   The appliance may include a battery, wherein the battery powers the motor that elevates the food transfer platform. One aspect of one embodiment allows a user to use the height-adjustable appliance as a food transfer platform alone. The user can move the food transfer platform vertically, using only battery power. Therefore, such a user need not be near an electrical outlet when using the height-adjustable appliance for food preparation only or adjusting to surfaces after moving. 
   The battery may be capable of recharging when the power cord is engaged with an electrical outlet. One aspect of one embodiment allows the food transfer platform to be moved vertically even when the appliance&#39;s power cord is not plugged into an electrical outlet. This allows the appliance to be used as an extra food preparation area, with the ability to provide proper height for up to 90 percent of the population. 
   A waste receptacle may be affixed to the food transfer platform. In one embodiment, there is an opening in the food transfer platform surface, with a waste receptacle underneath. Another embodiment may include an inset bin that may slide in underneath an aperture in the food transfer platform, for receiving waste during food preparation. One aspect of at least one embodiment allows the user to immediately discard excess or inedible parts of food during food preparation and cooking. 
   The appliance may also include a pull-out storage in the form of drawers in the food transfer platform. One aspect of one embodiment allows pots, pans, or utensils to be stored conveniently with the appliance. More particularly, plastic food preparation items, such as bowls or utensils, could be stored with the appliance, unlike with conventional electric ranges. 
   The appliance may have an adjustment mechanism between the column and the food transfer platform to allow the food transfer platform to be leveled or tilted. 
   The appliance may include a charger for charging the battery when the unit is stationary or not in use through the use of a separate low amperage charging cord. The motor controller may further provide a power converter to provide a necessary conversion of voltage between the battery, for example, a sealed lead acid battery, and the motor units. 
   The base may further include an upper cowling at each end and an upper cover that are upwardly convex to prevent items from being rested or stacked on the upper cowling or cover or balanced thereon. 
   The invention may further include a frame that supports and surrounds a downwardly extending tray which provides a bottom that is substantially below the frame allowing the extendible columns to descend to a point allowing the food transfer platform and heating element height to be as low as 27 inches and to extend as high as 42 inches. The bottom of the tray, as well as a battery and other circuitry provide the base. 
   One aspect of at least one embodiment of the invention is that the height-adjustable appliance has an extremely low center of gravity and an extremely low mounting point for the extendable columns. 
   It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but that modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments also be included as coming within the scope of the following claims. 
   Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings. These particular features and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a height-adjustable appliance such as may incorporate the present invention; 
       FIG. 2  is a fragmentary partial cross-section of the height-adjustable appliance; and 
       FIG. 3  is a schematic block diagram of the electrical connections of the height-adjustable appliance. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to  FIG. 1 , a height-adjustable appliance  10  of the present invention may include a generally horizontal and planar food transfer platform  12 , such as may be used for food preparation or as a cooking surface. 
   Preferably, the food transfer platform  12  is formed of a stainless steel sheet, for example a  16  gauge stainless steel sheet, and may have an upper area as much as thirty inches by sixty inches. The edges of food transfer platform  14  may be raised to provide a drip edge containing spilled liquids and upwardly extending glide rails  16  may be embossed in the food transfer platform  12 , providing upward ridges whose crests support the bottoms of pans or the like (not shown) to limit contact between the food transfer platform  12  and the pans reducing sliding friction, heat transfer, and contact with spilled liquids. 
   A heating element  18 , for example an induction heating unit, may be installed in the food transfer platform  12 , allowing for cooking of foods. The induction heating unit reduces the incidental heating of the food transfer platform and eliminates flame such as may ignite oils or the like. Alternatively element  18  may be a standard resistance type heating element. 
   Opposed ends of the food transfer platform  12  are supported by two corresponding extendible columns  20  whose upper ends attach to an underside of the food transfer platform  12  and whose lower ends are supported on a base  22 . 
   The base  22  provides a rectangular platform roughly the size of the food transfer platform  12  and may include wheels  24  in each corner to allow the base  22  to roll over a smooth floor  34  or the like. The base  22  includes an upper cowling  28  covering the upper surfaces of the base  22  which is upwardly convex to prevent items from being rested or stacked on the base  22  or balanced thereon. 
   Referring now also to  FIG. 2 , the base  22  may have a frame  32  being in a preferred embodiment a rectangular frame of square tube steel elevated sufficiently above the floor to receive on its underside the wheels  24 , which may be of food grade quality and which may provide foot actuated or electrically activated brakes  66 , and offset swivels as is understood in the art allowing the wheels  24  to rotate to align with the direction in which the base  22  is pushed. 
   The frame  32  supports and surrounds a downwardly extending tray  36  which provides a bottom supporting the bottom of the columns  20  that is substantially below the frame allowing the food transfer platform  12  and heating element  18  height to be as low as about 27 inches and to extend as high as about 42 inches. The bottom of the tray  36  also supports the batteries  40  and other circuitry as will be described providing the base  22  and thus the height-adjustable appliance with an extremely low center of gravity. 
   Referring to  FIGS. 1 and 3 , the heating element  18  may receive power from a retractable power cord  46  such as may be optionally provided with a spring-loaded retractor  47 . The cord  46  may extend from the base  22  to be plugged into a stationary outlet  48  when the height-adjustable appliance is positioned for cooking. Conductors of the cord  46  may pass through an elastomerically extensible tube  50 , such as a molded bellow, joining the base  22  and the food transfer platform  12  to restrain and guide the conductors. Alternatively or in addition, the conductors (not shown) extending between the base  22  and the food transfer platform  12 , may be coiled as with a telephone cable to reduce the chance of the conductors kinking or breaking throughout a range of extensions corresponding to different heights of the food transfer platform  12 . 
   At the food transfer platform  12 , power from the cord  46  may also be routed to two ground fault circuit interrupter (GFCI) outlets  26  that may be positioned on edges of the food transfer platform  12 . 
   The power from the cord  46  may also be routed to a controller  60  that may monitor the power, for example, to operate the electromagnetic brake or to provide a warning signal. 
   The periphery of the food transfer platform  12  along its vertical surface may include pressure-sensitive switches  54  and/or sensors  56 , such as infrared or ultrasonic sensors that may sense the proximity or contact of the edge of the food transfer platform  12  and other surfaces  68  to reduce the possibility of finger pinching when the food transfer platform  12  is raised or lowered. These switches  54  and sensors  56  may also communicate with controller  60 . Further, the sensors  56  may allow for automatic height adjustment when the food transfer platform  12  is moved between surfaces of different heights, for example, in the transfer of materials from one surface to another, aligning the top of the food transfer platform  12  with the adjacent surface to aid in the loading and unloading of materials. The sensors  56  may read particular encoded signals from infrared transmitters on adjacent work surfaces to signal the controller  60  to automatically change the height to be compatible with those work surfaces. 
   A control panel  58  may also be placed conveniently on an edge of the food transfer platform  12  to allow for control of the elevation through simple button presses communicated to the controller  60 . The control panel  58  may employ membrane switches  54  that may be easily cleaned. Similar standard controls  55  may be used for the induction or resistance heating elements  18 . 
   Referring still to  FIG. 3 , the motor controller  60  receives power from the battery  40  at a low voltage, for example, twelve volts, to provide power to motor units  38  controlling the extension or telescoping of the columns  20 . The motor units  38  may include height feedback signals through encoders or limit switches allowing the motor controller  60  to provide infinitely variable height adjustment from 27 inches to 42 inches as well as up to four pre-programmed height settings that may be accessed through preset buttons on the control panel  58 . 
   A charger  62  may be provided for charging the battery  40  when the unit is stationary through the use of a separate low amperage charging cord  64 . Alternatively, and, in addition, the charger  62  may connect to the cord  46  to provide charging when the cord  46  is plugged in. 
   An inset bin  70  may slide in underneath an aperture in the food transfer platform  12 , for example, for receiving waste during food preparation. Pull-out storage may be provided in the form of drawers in the food transfer platform (not shown). Adjustments may be provided between the columns  20  and the food transfer platform  12  to allow the food transfer platform  12  to be leveled or tilted. 
   An electromechanical brake  66  may be adjacent to the wheels  24 . The brake  66  may connect to the controller  60  to provide energy to engage the brake  66  when the power cord  46  is connected to an electrical outlet  48 . The controller  60  may also connect to the control  55  so that the brake  66  is engaged when the heating element  18  is energized. 
   Various alternatives and embodiments are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter regarded as the invention. 
   The present invention has been described in terms of the preferred embodiment, and it is recognized that equivalents, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.