WO1993010648A1 - Microwave stirring device - Google Patents

Abstract

A device for stirring food while it is being microwave heated, comprises a stirrer (6) and means (2) for mounting the stirrer so that it can rotate freely through a limited angle about a vertical axis in use of the stirrer. Thus, when the turntable of the microwave oven starts to turn, the stirrer will rotate in one direction or the other, depending on the direction of turntable rotation, so that the stirrer adopts a position in which it deflects food into the centre of the container (7), the food being effectively stirred and reaching a uniform temperature.

Description

Microwave Stirring Device

This invention relates to a device for stirring food while it is being microwave heated.

It has been found necessary to stir certain foods during microwave heating, thus spreading the heat evenly throughout the food. Without stirring, because microwaves do not penetrate more than 50mm into the food, the outside ends up much hotter than the centre. Therefore labels state, for example, "Microwave for 3 minutes, stirring occasionally". The only way to do this at present is to stop the microwave, stir by hand, then re-start the oven. This is inconvenient and prevents concentration on other jobs, and may result in food not being properly heated.

The aim of the invention is to provide a simple device whereby food is automatically stirred while being microwave heated. There have been several attempts hitherto to provide such a device, but they have tended to be complicated, or difficult to clean, or both.

According to the present invention, there is provided a device for stirring food while it is being microwave heated, said device comprising a stirrer, and means for mounting the stirrer so that it can rotate freely through a limited angle about a vertical axis, in use of the stirrer.

An embodiment of this invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a flexible support frame of a stirring device, the frame fitting into the lower edges of the microwave oven and being shown with its holder raised; Figure 2 is a view which shows the device with the holder lowered and the stirrer located in a food container within a microwave oven;

Figure 3 is a cross-section of the holder and stirrer shaft; Figure 4 shows some selected shapes of the stirrer blades; Figure 5 shows an alternative form of holder for the stirrer; and

Figure 6 is a diagrammatic plan view to show the manner in which the stirrer functions. Referring to Figure 1, there is shown a frame 1 that is resilient, allowing it to fit differing sizes of oven and being held in position in the oven by its springiness. This frame may be in one piece, or more than one for compact storage. The frame may have a different shape not here defined because there are many differing sizes and shapes of oven, and the shape of the frame is not important to the working of the device. Indeed, if the device were to be supplied as original equipment with a microwave oven, the frame may consist for example of a socketed arm or arms, or be for example a hinged holder sliding or bayonetting or by other means connecting with a fitment on the roof of the oven. An example is shown in Figure 5, in which a holder 2 has a first portion which attaches to the oven roof, and a second portion which receives the shaft 3 of a stirrer 6 and is pivotable relative to the first portion, and arranged to snap-engage with the first portion in either the vertical position shown, or in a horizontal position. In the example shown, the holder 2 is fixed to the oven roof with adhesive, but may instead comprise a suction pad.

Referring to Figure 2, fitted or clipped or attached to said frame 1 is a swinging central holder 2 into which the shaft 3 of stirrer 6 slides. The geometry of the frame and holder as shown ensures that the stirrer is positioned centrally within the oven opening but in front of the transverse centreline of the turntable 9. This in turn allows the stirrer shaft to protrude further through the holder when said holder is rotated as shown in Figure 1, thus enabling the stirrer to clear the rim of the dish.

As Figure 3 shows, the holder has a D shaped hole 4 while the stirrer has flats 5 on its shaft thus allowing it to rotate about its axis through a limited angle. This is because microwave turntables may rotate in either direction at random on start-up and the partial rotation allows the stirrer to align itself correctly for either direction of rotation.

In operation, the stirrer is placed in the dish 7, and while putting the dish into the oven the shaft of the stirrer is fitted into the holder 2. This is swung down (as shown by arrow 8) by hand at the same time as the dish is placed centrally on the turntable 9 of the oven 10. Alternatively, the dish can be placed centrally on the turntable, the stirrer fitted into the holder and then swung down into the dish. The stirrer then slides down through the holder into the food and rests against the bottom of the dish. It is also possible to rotate the complete frame assembly on its end against the floor of the microwave oven, allowing the stirrer to be placed in the dish, which has been previously been placed on the turntable. As shown in Figure 5, when the microwave oven is started the stirrer rotates one way or the other, depending which way the turntable rotates, the stirrer blade adopting an inclined position such that it deflects food from the outside, lifts it and redirects it towards the middle. This in turn pushes food from the middle towards the outside, thus mixing the food and therefore heating it evenly and in shorter time than without the stirrer. When heating is complete, the dish is removed with one hand while the other rotates the holder. The stirrer then slides out of the holder and stays in the dish of food, preventing any mess from drips.

Usually when microwaving food that is fairly liquid, it is necessary to cover the dish to prevent splashing, as the outside boils long before the centre is hot. With the stirrer in action, a cover can sometimes be dispensed with.

The stirrer blades can have different configurations for different foods, such as a single curved scoop blade, or three blades set at 120 degrees (see Figure 4) . There is provided if necessary a non-slip mat 11 with concentric rings marked on it, so that when the mat is placed on the turntable, the rings enable the user to place the dish reasonably centrally with ease: the mat prevents slippage of the dish relative to the turntable. The dish may be a special one with a high-friction base, instead of using the separate high-friction mat or relying on there being minimal slippage when using an ordinary container.

The complete frame is easily removable from the oven for cleaning or for using the microwave as a conventional oven or a combination oven. There is no change made to the oven itself.

There is thus provided by this invention a simple and convenient means of stirring food while being microwave heated. There is no extra washing up as the stirrer itself can be used as a spatula for removing food from its package, and for serving out.

This device can also be used for mixing materials other than foods.

Claims

1) A device for stirring food while it is being microwav heated, said device comprising a stirrer, and means fo mounting the stirrer so that it can rotate freely through limited angle about a vertical axis, in use of the stirrer.

2) A device as claimed in claim 1, in which the stirrer includes a shaft engaged or engageable with a holder in a manner permitting rotation of the stirrer through said limited angle about the axis of the shaft.

3) A device as claimed in claim 2 in which the holder is engaged or engageable with a support frame.

4) A device as claimed in claim 2, in which the holder is engageable with the roof of a microwave oven.

5) A device as claimed in any preceding claim, in which the stirrer is pivotable about a horizontal axis to lift it from an operative position within a food container.

6) A device as claimed in any preceding claim, in which the stirrer is disengageable from its mounting means.

7) A device for stirring food while it is being microwave heated, the device comprising a stirrer and means for mounting the stirrer so that, in use, it extends into a container of the food, the device being in combination with a frictional mat for preventing slippage between the container and a microwave oven turntable on which, in use, the container is placed.