Patent Application
20080190301
This invention generally relates to cooking apparatuses or equipment. More specifically, this invention relates to stir cookers.
Traditional cookers have a container sitting on a heater that has a thermal diffusion plate and a heating tube installed on the bottom of the diffusion plate and a handle for use of handling the container. When cooking, people have to stir food to facilitate heat transfer and uniform heating. Such cooking techniques include stir-frying, sautéing, braising, simmering, etc.; which require skill and labor.
In order to automate cooking processes, a stirring mechanism, which is installed inside the container for stirring food, has been proposed to facilitate heat transfer and uniform heating. The stirring mechanism is the key for cooking automation for fast and quality cooking and a “technological breakthrough” over traditional ways of cooking. Immediate advantages include: facilitated heat transfer and more uniform heating to save time and energy; reduced labor and skill requirements to consumers; closed lid on pan/pot to avoid cooking fumes and splashing for home environment protection, at the same time, save energy.
U.S. Pat. No. 6,845,707, issued to Xu, et al., on Jan. 25, 2006, teaches regarding an automatic cooking apparatus having a stirrer installed inside an inner pan for automated stirring and cooking.
U.S. Pat. No. 4,649,810, issued to Wong, on Mar. 17, 1987, illustrates an automatic cooking apparatus having a compartmentalized carousel for various ingredients of a particular dish to be loaded and a stirring blade generally conforming to the shape of the bottom of a cooking vessel. As the blade revolves around a vertical axis, it causes the foods to spread and to roll over the top of the blade.
However, prior art products have a full housing and a full heater in designs, resulting in being too bulky for kitchens and too expensive to manufacture. Market testing has shown that consumers desire a stir cooker of high performance, at the same time, compact and simple enough to be less bulky to save kitchen space and to be less expensive to manufacture.
Therefore, it remains desirable to provide a stir cooker that is innovative in design, such that it is less bulky to save kitchen space and less expensive to manufacture.
Accordingly, the present invention is a stir cooker. This stir cooker comprises a container having an open top and a sidewall for holding food, a lid for closing up the open top of the container, a support member fixedly engaged with the lower portion of the container and extended downward to a predetermined distance for adapting the container to sit on a base support or a horizontal counter top, a stirrer installed inside the container for stirring food, a heating tube installed on the bottom of the container for heating food, a co-rotation prevention member installed on the sidewall of the container for preventing food co-rotation with the stirrer, as the stirrer rotates, and a motor installed inside the base support and removably coupled with the stirrer for driving the stirrer.
Accordingly, the followings are some of the objects, features, and advantages of the present invention.
It is an object of the present invention to provide a stir cooker that is simple to use, less bulky to save kitchen space, and less expensive to manufacture.
It is a feature of the present invention that this stir cooker includes a support member for supporting the container. The upper end of the support member is fixedly engaged with the periphery of the bottom portion of the container and the lower end of the support member extends downward to a predetermined distance for adapting the container to stand on a base support or on a horizontal surface.
It is another feature of the present invention that the heating tube is fixedly installed on the bottom of the container to save some cost associated with a heater having a thermal diffusion plate, which requires significant amount of material and space. By directly installing the heating tube on the bottom of the container heating efficiency is also significantly enhanced.
It is a further more feature of the present invention that a thermostat is removably engaged with the bottom of the container for detecting and limiting the temperature and controlling the heating tube.
It is a still further more feature of the present invention that the container is not enclosed inside a housing, such that some cost and space associated with a full housing is saved, compared with prior art products.
It is an advantage of the present invention that the stir cooker is highly compact to save space and material cost.
Further more features and advantages of the present invention will be readily appreciated, as the same becomes better understood after reading the subsequent description when considered in connection with the non-limiting accompanying drawings.
Reference is made to
A container 102, having an open top, a sidewall, and a central aperture on the bottom, is provided for holding food. The sidewall of container 102 is slightly tapered with a larger diameter on the top and a smaller diameter on the bottom. Container 102 is, preferably, coated with a non-stick material.
A lid 104 is provided for closing up the open top of container 102. Lid 104 is, preferably, made of a transparent material.
A grasp handle 106 and a lift handle 108 are fixedly installed on the upper portion of the sidewall of container 102 for use of handling container 102.
A support member 110, having a generally tapered hollow cylindrical configuration, is provided for supporting container 102. The upper end of support member 110 is fixedly engaged with the periphery of the bottom portion of container 102 and the lower end of support member 110 is extended downward to a predetermined distance such that container 102 is adapted to stand on a base support 112 or on a horizontal countertop. Support member 110 is also provided for enclosing the space underneath the bottom of container 102 into a protected space. Some windows or slots may be opened on support member 110 for venting heat etc.
A stirrer 114, removably installed inside container 102, is provided for stirring food. The clearance between the lower edge of stirrer 114 and the bottom of container 102 is minimized for better stirring performance. The profile of stirrer 114 is optimized for minimizing stirring resistance, such that less motor power is required to drive stirrer 114, which saves some cost on motors.
An electrical heating tube 116, having a generally circular configuration, is provided for heating food disposed inside container 102. Heating tube 116 is fixedly installed on the outside surface of the bottom of container 102, inserted into a groove formed on the bottom of container 102, and disposed close to the periphery with a predetermined distance. The two electrical terminals of heating tube 116 extend downward to a predetermined distance and are adapted to removably engage with an electrical power supply, as container 102 is installed in position on base support 112. There are significant advantages of installing heating tube 116 directly on the bottom of container 102. These advantages include saving a significant amount of material for building a full heater that has a thermal diffusion plate, resulting in space and cost saving and higher heat transfer efficiency due to the direct attachment of heating tube 116 on the bottom of container 102, etc.
A plurality of co-rotation prevention members 118 is integrally constructed inside container 102, on the sidewall, for preventing food pieces from co-rotating with stirrer 114, as stirrer 114 rotates. Members 118 include a rib-shaped elongated member that extends generally vertical along the sidewall of container 102. The upper ends of members 118 extend substantially to the upper portion of container 102. Members 118 are preferably disposed substantially dose to handles 106 or 108 such that members 118 would not obstruct food unloading. Members 118 extend inward to a predetermined distance, away from the sidewall of container 102. The predetermined distance is determined based on the size of container 102. Proper clearance between members 118 and stirrer 114 should be maintained. When food co-rotates with stirrer 114 and runs against members 118, as stirrer 114 rotates, food pieces at a higher level close to members 118 would be stopped and tumbled down due to gravity, resulting in better mixing or stirring of food, thereby facilitating heat transfer to and uniform heating of food.
A thermo plate 120, made of a material of high thermal conductivity, is fixedly installed on the bottom of container 102, at a location substantially dose to heating tube 116, for removably engaging a thermostat 122. Thermostat 122 is installed on base support 112 and engaged with thermo plate 120 for detecting the temperature as container 102 is installed in position on base support 112. Such temperature is used to control the electrical power to heating tube 116. The upper end of thermostat 122 protrudes upward above the upper surface of base support 112 with pre-loading, e.g., via a spring 122a. Thermostat 122 can be a digital sensor, such as a NTC or PTC, or an adjustable thermostat, or simply a temperature switch, as known to those skilled in the art.
Base Support 112, disposed underneath container 102, is provided for supporting container 102. The upper portion of base support 112 is removably engaged with the inner periphery of the lower portion of support member 110. As container 102 is installed in position on base support 112, thermostat 122 is engaged with thermo plate 120, or directly with the bottom of container 102, and the electrical terminals of heating tube 116 are removably connected with an electrical port 112c on base support 112.
A motor 124 is installed inside base support 112 for providing rotation power to stirrer 114. Motor 124 is removably coupled with a drive shaft 126, as container 102 is installed in position. Drive shaft 126 is threaded through the central aperture on the bottom of container 102. The upper end of shaft 126 is engaged with stirrer 114 and the lower end of shaft 126 is coupled with motor 124 through a coupling device 132. A seat device 130 is provided for sealing off the interface between shaft 126 and the bottom of container 102.
Drive shaft 126 is threaded through the central aperture on the bottom of container 102. The upper end of shaft 126 is engaged with stirrer 114 and the lower end of shaft 126 extends downward through the central aperture on the bottom of container 102, leading to coupling device 132. Coupling element 132a is engaged with the lower end of shaft 126. Coupling element 132b is engaged with a motor shaft 134.
Bushing 136 is co-axial to shaft 126 and is fixedly and sealingly engaged with the bottom of container 102. Packing 138 is inserted inside a groove cut around shaft 126. A plurality of packing 138 can be provided for more reliable sealing, as known to those skilled in the art. When inserted into bushing 136 together with shaft 126, packing 138 is compressed and squeezed against shaft 126 and bushing 136 to seal off the interface thereof. Bushing 136 extends upward to a predetermined height above the bottom of container 102, such that the upper end of bushing 136 and packing 138 are disposed above the bottom of container 102 and such that the requirement on seal device 130 is significantly reduced. The tolerance between bushing 136 and shaft 126 is minimized for ideal sealing performance, but, at the same time, shaft 126 should be able to rotate with minimal friction resistance, which requires high precision of the fitting surfaces thereof.
Materials for packing 138 are extremely important when selecting the proper packing for an application. Basic requirements include heat resistance, wearing resistance, elasticity, etc.
Seal device 130 can, alternatively, take many other forms, such as bushing, labyrinth, packing, or combinations of multiple forms for ideal performance, as known to those skilled in the art and suggested by this invention disclosure.
Accordingly, as container 102 is properly installed in position on base support 112, thermostat 122 is engaged with thermo plate 120, or directly with the bottom of container 102, the electrical terminals of heating tube 116 are connected with electrical port 112c, motor 124 is coupled with shaft 126, and detector 128 is depressed to confirm that container 102 is well in position. Stir cooker 100 is, now, ready for cooking.
Motor 124 is directly installed on the bottom of container 102. A plurality of insulation block 202 is provided in between motor 124 and the bottom of container 102 for shielding motor 124 away from heat transferred from the bottom of container 102. An adjustable thermostat 204, installed directly on the bottom of container 102, is provided for controlling the temperature of heating tube 116. A bottom cap 206 is provided for closing the bottom opening of support member 110.
Reference is made to
Accordingly, readers will see that this stir cooker of the present invention is highly compact to save kitchen space and manufacturing cost. The container is removable from the base support, such that it is convenient for cleaning after use and dishwasher safe.
The present invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.
Although this invention has been described in its preferred forms and structures with a certain degree of particularity, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.
Thus it is understood that the present disclosure of the preferred forms can be changed in the details of construction and in the combination and arrangement of parts without departing from the spirit and the scope of the invention as hereinafter claimed.
