Electric heating – Heating devices – With current connection and/or disconnection means
Reexamination Certificate
2000-10-25
2001-07-31
Leung, Philip H. (Department: 3742)
Electric heating
Heating devices
With current connection and/or disconnection means
C219S708000, C219S720000, C219S754000, C099S325000, C177S084000, C177S048000
Reexamination Certificate
active
06268593
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to cooking apparatuses and, more particularly, to a cooking apparatus capable of determining a weight of food to be heated.
2. Description of the Background Art
A conventional cooking apparatus may include a weight sensor for detecting a weight of food in a heat chamber. Such a cooking apparatus automatically determines a heating time or the like based on the detected weight of food for cooking.
Examples of such a weight sensor include a device outputting a pulse signal at a different timing according to the weight of food. The weight sensor detects the pulse signal output from the above mentioned device and determines the weight of food based on the timing at which the pulse signal is detected. The cooking apparatus uses the determined weight of food for automatic cooking.
However, the weight sensor suffers from a problem that the pulse signal may not be properly detected due to an external noise or the like. In such a case, the detected weight of food considerably deviates from the actual weight, so that a user does not satisfy with the automatic cooking performed by the cooking apparatus.
SUMMARY OF THE INVENTION
The present invention is made to solve the aforementioned problem. An object of the present invention is to provide a cooking apparatus provided with a weight sensor capable of accurately detecting a weight of food.
According to one aspect of the present invention, the cooking apparatus includes: a turn table on which food is to be placed for periodic rotation; a weight indicating portion; a signal outputting portion; and a weight determining portion. The weight indicating portion has a magnet, varies a magnetic field intensity in a prescribed position with a prescribed frequency (number of times) in a rotation period of the turn table, and changes a timing at which the magnetic field intensity varies in the prescribed position in the rotation period of the turn table according to the weight of food placed on the turn table. The signal outputting portion outputs a pulse signal differently according to the variation in the magnetic field intensity in the prescribed position. The weight determining portion receives the signal output from the signal outputting portion for determining the weight of food according to a timing of receiving the pulse signal in the rotation period of the turn table. Note that the weight determining portion determines the weight of food only when the pulse signals are received with the prescribed frequency in the rotation period of the turn table.
According to the present invention, the weight determining portion determines the weight of food only when the pulse signals are properly received. In other words, if the weight determining portion does not receive the pulse signals with the prescribed frequency during one rotation of the turn table, the pulse signals received by the weight determining portion in that rotation of the turn table are ignored in detecting the weight of food. Then, the weight of food is detected based on the pulse signals subsequently received by the weight determining portion.
Thus, even if the pulse signals to be used for the determination of the weight of food are not properly transmitted/received or a pulse signal affected by an external noise is present under certain circumstances, the pulse signal that is considered to have been adversely affected would not be used for the detection of the weight of food. Thus, the weight of food can be detected more accurately in the cooking apparatus.
In the cooking apparatus of the present invention, preferably, if a frequency of receiving the pulse signals output from the signal outputting portion in the rotation period of the turn table is less than the prescribed frequency, the weight determining portion determines the weight of food according to the timing of receiving the pulse signals in a subsequent rotation period of the turn table.
The cooking apparatus of the present invention further includes a heating portion heating food to be heated, and a heat controlling portion controlling a heating operation of the heating portion. The heat controlling portion preferably ends the heating operation of the heating portion in the event that the weight determining portion fails to receive the pulse signals output from the signal outputting portion during one rotation of the turn table with the prescribed frequency after such event successively occurs with a given frequency.
Thus, the cooking apparatus would not continue to heat when it is in some kind of trouble.
Preferably, the cooking apparatus of the present invention includes a notifying portion. The notifying portion notifies the event that the weight determining portion fails to receive the pulse signals output from the signal outputting portion during one rotation of the turn table with the prescribed frequency after such event successively occurs with the given frequency.
Thus, a user can easily realize that the weight determining portion cannot determine the weight of food properly.
The cooking apparatus of the present invention preferably includes a notifying portion. The notifying portion notifies that the weight determining portion cannot properly determine the weight of food if the weight determining portion has never received the pulse signal from the signal outputting portion in a prescribed time period.
The cooking apparatus of the present invention preferably includes a sound generating portion and a sound setting portion. Note that the sound generating portion can generate a plurality of different sound patterns which have been preliminary set and generates a sound if a prescribed condition is met. The sound setting portion sets the sound pattern to be generated by the sound generating portion among the plurality of sound patterns. It is noted that the sound generating portion generates a sound according to the set sound pattern when the sound pattern is set by the sound setting portion.
The cooking apparatus according to another aspect of the present invention includes: a turn table on which food is to be placed for periodic rotation; a weight indicating portion; a signal outputting portion; and a weight determining portion. The weight indicating portion has a magnet, varies a magnetic field intensity in a prescribed position with a prescribed frequency in a rotation period of the turn table, and changes a timing at which the magnetic field intensity in the prescribed position changes in the rotation period of the turn table according to the weight of food placed on the turn table. The signal outputting portion differently outputs pulse signals according to the variation in the magnetic field intensity in the prescribed position. The weight determining portion receives a signal output from the signal outputting portion for determining the weight of food according to the timing of receiving the pulse signal in the rotation period of the turn table. If the weight determining portion receives two different pulse signals at an interval shorter than a prescribed interval, it invalidates the second one of the received two pulse signals.
According to the present invention, if the weight determining portion receives a pulse signal at an unusual timing with respect to reception of a pulse signal which has been received immediately before, that unusually received pulse signal is determined an external noise and ignored in detecting the weight of food.
Thus, if the pulse signals used for the determination of the weight of food are not transmitted/received properly under certain circumstances, the pulse signal which is considered to have been adversely affected by abnormal transmission/reception would not be used in detecting the weight of food. Accordingly, the cooking apparatus can detect the weight of food more accurately.
A method of detecting a weight of food on a turn table according to still another aspect of the present invention refers to a method of detecting a weight of food placed on a turn table of a cooking apparatus includi
Armstrong Westerman Hattori McLeland & Naughton LLP
Leung Philip H.
Sanyo Electric Co,. Ltd.
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