GB2173902A - Weighing electrically - Google Patents
Weighing electrically Download PDFInfo
- Publication number
- GB2173902A GB2173902A GB08509781A GB8509781A GB2173902A GB 2173902 A GB2173902 A GB 2173902A GB 08509781 A GB08509781 A GB 08509781A GB 8509781 A GB8509781 A GB 8509781A GB 2173902 A GB2173902 A GB 2173902A
- Authority
- GB
- United Kingdom
- Prior art keywords
- food
- weight
- electrode plate
- food weight
- pivotable
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/6408—Supports or covers specially adapted for use in microwave heating apparatus
- H05B6/6411—Supports or covers specially adapted for use in microwave heating apparatus the supports being rotated
-
- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
- A47J37/00—Baking; Roasting; Grilling; Frying
- A47J37/04—Roasting apparatus with movably-mounted food supports or with movable heating implements; Spits
- A47J37/046—Roasting apparatus with movably-mounted food supports or with movable heating implements; Spits with horizontal turntables
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
- G01G19/40—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight
- G01G19/413—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means
- G01G19/414—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means using electronic computing means only
- G01G19/4146—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups with provisions for indicating, recording, or computing price or other quantities dependent on the weight using electromechanical or electronic computing means using electronic computing means only for controlling caloric intake, e.g. diet control
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G19/00—Weighing apparatus or methods adapted for special purposes not provided for in the preceding groups
- G01G19/52—Weighing apparatus combined with other objects, e.g. furniture
- G01G19/56—Weighing apparatus combined with other objects, e.g. furniture combined with handles of tools or household implements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
- G01G3/02—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a helical spring
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G7/00—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups
- G01G7/06—Weighing apparatus wherein the balancing is effected by magnetic, electromagnetic, or electrostatic action, or by means not provided for in the preceding groups by electrostatic action
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/6447—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors
- H05B6/6464—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors using weight sensors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Mathematical Physics (AREA)
- Theoretical Computer Science (AREA)
- Food Science & Technology (AREA)
- Electric Ovens (AREA)
Abstract
A food weight measurement device comprises a table 4 for carrying a foodstuff, a pivotable electrode plate 20 for receiving the food weight, the pivotable electrode plate being pivotably moved responsive to the food weight against a spring 23, a fixed electrode plate 18 for providing electrical signals corresponding to the food weight in by forming a capacitor with the pivotable electrode plate, and an output circuit responsive to the fixed electrode plate for outputting electrical signals representative of the food weight. The device is incorporated in a microwave oven. <IMAGE>
Description
SPECIFICATION
Food weight measuring device for cooking appliance
BACKGROUND OF THE INVENTION
The present invention relates to a food weight measuring device and, more particularly, to a food weight measuring device for a cooking appliance such as a microwave oven which can exactly measure weight of food stored in a heating chamber based on a change in static electric capacity.
In a conventional microwave oven, various techniques have been proposed so that a heating period of the oven is selected depending on the weight of food after weight of food stored on a turntable in the heating chamber of the microwave oven is measured.
One example of the weight measuring devices functions in a such manner that three supporting rollers provided at three positions of peripheral portion of the turntable receive load applied to the turntable and the weight of food is detected by changing the power received by the three rollers into a displacement of position. However, in the above measurement, the powers received by each of the three supporting rollers, namely, the displacement of the positions, must be concentrated on one point. Therefore, the construction of the food weight measuring device may be complex and the wide spaces for disposing the device is needed. Also, the device may become expensive.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present
invention to provide a food weight measuring device for a cooking appliance which has a
simple and compact construction.
It is another object of the present invention to provide a food weight measuring device for a cooking appliance which can exactly mea
sure weight of food in a cooking chamber
based on a change in static electric capacity.
It is still another object of the present invention to provide a microwave oven in a turntable type which comprises a food weight
measuring means for measuring weight of food placed on a turntable disposed in a heat
ing chamber depending on a change in static
electric capacity of a condenser formed between two electrode plates.
Other objects and further scope of applica
bility of the present invention will become ap
parent from the detailed description given
hereinafter. It should be understood, however,
that the detailed description of and specific
examples, while indicating preferred embodi
ments of the invention, are given by way of
illustration only, since various changes and
modifications within the spirit and scope of
the invention will become apparent to those
skilled in the art from this detailed description.
To achieve the above object, according to an embodiment of the present invention, a food weight measurement device comprises table means for carrying a foodstuff, pivotal means for receiving the food weight, the pivotal means being pivotably moved responsive to the food weight, fixed means for providing electrical signal corresponding to the food weight in cooperation with the pivotal means, and output means responsive to the fixed means for outputting electrical signal representative of the food weight.
When the present invention is applied to an microwave oven, the microwave oven comprises a food weight measuring device for measuring weight of food placed on a turntable rotatably disposed in a heating chamber of the microwave oven, the food weight measuring device comprising a pivotable electrode plate downwardly pressed by a lower end of a turntable shaft via a steel ball, and a fixed electrode plate disposed adjacent to the pivotable electrode plate with a small gap between the two electrode plates. One end of the pivotable electrode plate is connected to a fulcrum pivotably supporting the pivotable electrode plate according to the up/down movement of the turntable shaft while the other end of the pivotable electrode plate is connected to an elastic material such as a spring for elastically supporting the pivotable electrode plate.The weight of food placed on the turntable can be detected by measuring the variation of a capacity of a condenser formed between the pivotable plate and the fixed electrode plate.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better under
stood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein:
Figure 1 shows a sectional view of a food weight measuring device disposed in a mi
crowave oven;
Figure 2 shows a side view of the food
weight measuring device disposed in the mi
crowave oven of Fig. 1; and
Figure 3 shows a view for explaining a mea
suring principle of the food weight measuring
device of Fig. 1.
DETAILED DESCRIPTION OF THE INVENTION
A food weight measuring device of a pre
ferred embodiment of the present invention
applied to a microwave oven in a turntable
type will be described with reference to Fig. 1
and 2. The present invention may be applied
to various apparatus except the microwave
oven.
A turntable shaft 2 is projected from a sub
stantial center portion of a bottom wall of a
heating chamber 1 of a microwave oven. A
turntable seat plate 3 is disposed on a top end of the turntable shaft 2. A boss portion 3-1 of the turntable seat plate 3 is suitably engaged with the top end of the turntable shaft 2 with a suitable construction. The engagement between the boss portion 3-1 and the turntable shaft 2 prevents a flange portion 3-2 of the turntable seat plate 3 from shaking
in the up/down directions and is easily removable therebetween.
A turntable 4 is carried on the turntable seat plate 3 for carrying food (not shown) to be cooked. Projection portions 4-1 are provided on the rear surface of the turnable 4, and is in contact with a peripheral edge of the turntable seat plate 3 to position the turntable 4.
To prevent leak of microwave, a choke member 5 is connected to the bottom plate of the heating chamber 1 by nuts 6. A first bearing supporting member 7 and a second bearing supporting member 8 are connected to the choke member 5 by nuts 9 to form a choke construction. Bearings 10 are supported by the first bearing supporting member 7 and the second bearing supporting member 8, respectively, and are connected to the first bearing supporting member 7 and the second bearing supporting member 8 by nuts 11.
The turntable shaft 2 is inserted into the two bearings 10. A turntable gear 12 is disposed in a space between the first bearing supporting member 7 and the second bearing supporting member 8. The turntable gear 12 is fixed to the turntable shaft 2 by a pin 13 to thereby sliply unrotate the gear 12. A chassis 14 is fixed to a rear surface of the second bearing supporting member 8 by nuts 15.
An electrode casing 16 is connected to the chassis 14 by nuts 17 and is made of an insulative material. A fixed electrode plate 18 is fixed on a horizontal surface of a step portion of the electrode casing 16 by nuts 19.
Over the fixed electrode plate 18, a pivotable electrode plate 20 spaced from the fixed electrode plate 18 with a predetermined space is pivotably provided in the electrode casing 16.
Preferably, the space between the fixed electrode plate 18 and the pivotable electrode plate 20 is approximately about 1 mm. One end of the pivotable electrode plate 20 is pivotably connected to the side wall of the electrode casing 16 by a pin 21, so that the pivotable electrode plate 20 can rotate in an arrow direction A around the pin 21 (namely, a fulcrum). The free end portion 20-1 of the pivotable electrode plate 20 is bent in an Lshaped form. The vertical portion of the Lshaped end portion of the pivotable electrode plate 20 is inserted thorugh and projected from a hole 22 formed in the end portion of the the chassis 14. One end of an elastic member such as a spring 23 is inserted into a hole 24 formed in the end of the vertical surface of the L-shaped end of the pivotable electrode plate 20.The elastic member is hooked with the L-shaped portion of the pivotable electrode plate 20. The other end of the spring 23 is connected to the spring angle 25 disposed on the chassis 14 by a nut 28 via an adjacent plate 26 and an adjacent screw 27. The adjacent plate 26 and the adjacent screw 27 are provided for controlling a spring constant of the spring 23 and the initialized space between the pivotable electrode plate 20 and the fixed electrode plate 18, respectively.
A steel ball receiver 30 made of an insulating material is provided at the substantial center portion of the pivotable electrode plate 20 for receiving a steel ball 29. The steel ball 29 is stored into a steel ball storing portion of the lower end of the turntable shaft 2 having a circular-cone shaped concave. Accordingly, the turntable shaft 2 is indirectly connected to the pivotable electrode plate 20 thorugh the steel ball 29.
The turntable shaft 2 can rotate by the bearings 10 in a radial direction against a load (food) applied to the turntable 4, and can rotate by the steel ball 29 stored in the circularcone shaped concave portion provided at the lower end of the turntable shaft 2 in a thrust direction.
A motor 31 is disposed on a rear surface of the chassis 14 for driving the turntable shaft 2. A motor gear 32 is connected to the rotating shaft of the motor 31. The motor gear 32 is engaged with the turntable gear 12 through a hole 33 formed in the side wall of bearing plate 8 so that the rotation of the motor 31 is transmitted to the turntable shaft 2.
The fixed electrode plate 18 and the movable electrode plate 20 are made of a metal material, and are insulatively provided therebetween to form one type of air condensers.
Lead lines (not shown) are connected to the pivotable electrode plate 20 and the fixed electrode plate 20, respectively. The lead lines are also connected to a resistance externaily pivoted. The electrode plates 18, 20, and the resistance forms an oscillator by combining the capacity between the electrode plates 18 and 20 with the resistance. An oscillating frequency from the oscillator is detected so that a frequency corresponding to the weight of food to be cooked disposed on the turntable 4 is obtained. A cooking information such as a heating period is selectively decided based on the output signal depending on the detected frequency. The cooking information may be stored into the read only memory (ROM).
A food weight measuring method will be described with reference to Fig. 3. b designates a radius of the movable electrode plate 20, and a designates a diameter of the movable electrode plate 20. d designates a space between the fixed electrode plate 18 and the pivotable electrode plate 20, and k designates an elastic constant of the spring 23.
When a load (namely, food to be cooked) of weight Wg is applied to the substantial center portion of the turntable 4, the turntable shaft 2 is slidably moved down while the turntable shaft 2 is supported by the bearings 10, and the force of the weight Wg presses the steel ball receiving portion 30 of the pivotable electrode plate 20 via the steal ball 29. In this case, the movable electrode plate 20 is moved in the lower direction indicated by the arrow A around the pin 21, so that the rotating spring 23 is pulled by a force of
b b W. W. Depending to the force of W, a a the spring 23 is extended by a length of 1 b -. -. W, so that K a the weight of food on the turntable 4 and the extension of the spring 23 are balanced and the movement of the pivotable electrode plate 20 is stopped.
In this time, the turntable shaft 2 is slidably moved down with the width of
1 b2 -. -. W. Depending on the rotation K a2 of the pivotable electrode plate 20, the width d between the end of the pivotable electrode plate 20 connected to the spring 23 and the fixed electrode plate 18 is narrowed with a
1 b width of -. -. W more than an initialized
K a width (the initialized width is decided when food to be cooked is not disposed on the turntable 2.). The space between the end of the pivotable electrode plate 20 connected by the pin 21 and the fixed electrode plate 18 does not change.
Depending on the variation of the width between the electrode plates 18 and 20, the capacity C of the condenser formed between the electrode plates 18 and 20 is changed. If the condenser is connected to a resistance externally provided to form the oscillator with the electrode plates 18 and 20, the oscillator outputs an oscillating frequency of
1 ~where f C.R R designates a resistance value and C designates a capacity of the condenser. Accordingly, the variation of the capacity C reads as the variation of the oscillating frequency, so that the output signal substantially proportional to the weight W of food to be cooked can be outputted.
As described above, when the food to be cooked is put on the turntable 4, the weight of food is measured. Because the output signal according to the weight of food is outputted from the oscillator or a processing circuit, the cooking operation such as the heating period, the heating temperature, rotating speed of the turntable or the like, are controlled and automatically selected. According to the weight of food, the information of the heating operation is selected from data stored in the memory.
For a defrost mode of freezed food in the conventional oven, the weight of each of freezed food must be measured. Further, the weight of the food must be manually inputted by operting keys. Such operation can be eliminated by the present invention.
As described above, the microwave oven of the present invention comprises a food weight measuring device includes the pivotable electrode plate downwardly pressed by the lower end of the turntable shaft rotatably disposed in the heating chamber via the steel ball, and the fixed electrode plate disposed in the neighborhood of the pivotable electrode plate with the narrow gap between the two electrode plates, wherein the end of the pivotable electrode plate is pivotably connected for rotating according to the up/down movement of the turntable shaft while the other end of the pivotable electrode plate is elastically connected to the elastic member such as the spring. Therefore, the weight of food carried on the turntable is measured by measuring the capacity of the condenser formed between the pivotable electrode plate and the fixed electrode plate which is varied depending on the weight of food carried on the turntable. Accordingly, the weight of food can be automatically measured by translating from the weight to the movement of the turntable shaft.
Therefore, a simple and reasonable microwave oven can be provided with high quality.
The length of the pivotable electrode plate 20 may be substantially equal to that of the fixed electrode plate 18.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications are intended to be included within the scope of the following claims.
Claims (6)
1. A food weight measurement device comprising:
table means for carrying a foodstuff;
pivotal means for receiving the food weight, the pivotal means being pivotably moved responsive to the food weight;
fixed means for providing electrical signal corresponding to the food weight in cooperation with the pivotal means; and
output means responsive to said fixed means for outputting electrical signal representative of the food weight.
2. The food weight measurement device of claim 1, wherein the pivotal means and the fixed means form a condenser.
3. The food weight measurement device of claim 3, wherein the electrical signal corresponding to the food weight relates to a C R constant.
4. A food weight measuring device for measuring weight of food carried on table means comprising:
pivotable electrode means downwardly pressed by a lower end of a table means shaft;
fixed electrode means disposed adjacent to the pivotable electrode means with a small gap between the electrode means, wherein one end of the pivotable electrode means is connected to a fulcrum pivotably supporting the pivotable electrode means according to the up/down movement of the table means shaft while the other end of the pivotable electrode means is connected to an elastic member for elastically supporting the pivotable electrode means, and wherein the weight of food is measured by measuring the variation of a capacity of a condenser formed between the pivotable electrode means and the fixed electrode means.
5. Cooking apparatus provided with a food weight measuring device which comprises a variable capacitor so arranged that its capacitance changes in response to the weight of the food.
6. A food weight measuring device substantially as herein described with reference to the accompanying drawing.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB08509781A GB2173902B (en) | 1985-04-16 | 1985-04-17 | Food weight measuring device for cooking appliance |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/724,072 US4615405A (en) | 1985-04-16 | 1985-04-16 | Food weight measuring device for a cooking appliance |
GB08509781A GB2173902B (en) | 1985-04-16 | 1985-04-17 | Food weight measuring device for cooking appliance |
Publications (3)
Publication Number | Publication Date |
---|---|
GB8509781D0 GB8509781D0 (en) | 1985-05-22 |
GB2173902A true GB2173902A (en) | 1986-10-22 |
GB2173902B GB2173902B (en) | 1988-12-21 |
Family
ID=26289135
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB08509781A Expired GB2173902B (en) | 1985-04-16 | 1985-04-17 | Food weight measuring device for cooking appliance |
Country Status (1)
Country | Link |
---|---|
GB (1) | GB2173902B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0359976A1 (en) * | 1988-09-02 | 1990-03-28 | Matsushita Electric Industrial Co., Ltd. | Automatic heating appliance with weight sensor |
GB2223849A (en) * | 1988-08-09 | 1990-04-18 | Hanson | Scale |
GB2373980A (en) * | 2001-03-27 | 2002-10-02 | Nicholas Robert Jones | Microwave turntable weighing system |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2047410A (en) * | 1979-04-10 | 1980-11-26 | Soehnle Waagen Gmbh & Co | Weighing apparatus with digital display |
GB2083925A (en) * | 1980-09-24 | 1982-03-31 | Raytheon Co | Microwave Oven |
GB2084436A (en) * | 1980-09-24 | 1982-04-07 | Raytheon Co | Microwave Oven |
GB2106760A (en) * | 1981-10-01 | 1983-04-13 | Montier Carter Arthur Charles | Microwave heaters |
-
1985
- 1985-04-17 GB GB08509781A patent/GB2173902B/en not_active Expired
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2047410A (en) * | 1979-04-10 | 1980-11-26 | Soehnle Waagen Gmbh & Co | Weighing apparatus with digital display |
GB2083925A (en) * | 1980-09-24 | 1982-03-31 | Raytheon Co | Microwave Oven |
GB2084436A (en) * | 1980-09-24 | 1982-04-07 | Raytheon Co | Microwave Oven |
GB2106760A (en) * | 1981-10-01 | 1983-04-13 | Montier Carter Arthur Charles | Microwave heaters |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2223849A (en) * | 1988-08-09 | 1990-04-18 | Hanson | Scale |
EP0359976A1 (en) * | 1988-09-02 | 1990-03-28 | Matsushita Electric Industrial Co., Ltd. | Automatic heating appliance with weight sensor |
US4970374A (en) * | 1988-09-02 | 1990-11-13 | Matsushita Electric Industrial Co., Ltd. | Automatic heating appliance with weight sensor |
GB2373980A (en) * | 2001-03-27 | 2002-10-02 | Nicholas Robert Jones | Microwave turntable weighing system |
Also Published As
Publication number | Publication date |
---|---|
GB8509781D0 (en) | 1985-05-22 |
GB2173902B (en) | 1988-12-21 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19970417 |