JP2007218524A - Sensor for gas table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor for a gas table, which is inexpensive with a simple structure and easy to assemble without requiring many man-hours, and can accurately detect placing of a cooking utensil. <P>SOLUTION: The sensor comprises a contact part 14 which makes contact with the cooking utensil 12 when it is placed on a gas table and is elastically energized to be movable by the cooking utensil 12; a conduit 16 connected with the contact part 14; a cable 20 inserted to the conduit 16 and connected with the contact part 14; a magnetic body 22 fixed to a proper position of the cable 20; and a coil 18 wound on the outer circumference of the conduit 16 in which the magnetic body 22 is located. When the contact part 14 is moved by the cooking utensil 12, the cable 20 is interlocked therewith to move the magnetic body 22 within the conduit 16 in the coil 18, whereby the cooking utensil 12 is detected. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a gas table sensor for detecting that a cooking utensil such as a pan is placed on a gas burner of a gas table or a gas stove.

  Conventionally, a detection device for detecting that a cooking utensil such as a pan is placed on a gas table or a gas stove. This detection device is composed of a combination of a reed switch, a magnetic body, and a permanent magnet. Then, an abutting portion elastically biased in a protruding state is provided at the center of the gas burner such as a gas table, and when a pan or the like is placed, the abutting portion abuts on the bottom of the pan or the like and descends, The magnetic body fixed to the connected cable is located between the reed switch and the magnet, and the magnetic force of the magnet is transmitted to the reed switch through the magnetic body, and the reed switch is turned on to detect a pan or the like. It was.

  Patent Document 1 discloses a tempura oil fire prevention sensor. This sensor is disposed in the vicinity of the center of the gas burner of the gas table, and a sensor portion is formed so as to be able to elastically contact the bottom of the pan. The magnet moves while the bimetal inside the sensor is deformed by the temperature of the tempura oil during cooking, and the reed switch is operated by the magnetic force.

  Also in Patent Document 2, as an automatic fire extinguishing device for a cooking device, a temperature-sensitive member that is provided in a heat-sensitive portion elastically biased near the center of the gas burner, and whose magnetic permeability changes depending on the temperature, is adsorbed to and detached from this temperature-sensitive member An automatic fire extinguishing device at the time of abnormal heating having a reed switch interlocked with this magnet as a component is shown.

In addition, a switch disclosed in Patent Document 3 has been proposed as a switch that opens and closes a reed switch when the moving body moves forward and backward. In Patent Document 3, a columnar moving body with a built-in reed switch is inserted into the openings of two ring-shaped magnets fitted coaxially, and when the moving body moves, the reed switch is moved due to a change in magnetic force. A configuration for turning on or off is disclosed.
JP-A-9-303725 Japanese Unexamined Patent Publication No. 2000-247331 Japanese Patent Laid-Open No. 11-67035

  In the above prior art, it is necessary to align the positions of the three members of the permanent magnet and magnetic body of the detection device provided in the gas table or gas stove, and the reed switch, in an appropriate parallel position, and accurately fix it. It took time to assemble and was complicated and costly. Further, when the permanent magnet is heated by the heat transmitted from the gas burner, the magnetic force is reduced and the operation is not stable.

  Moreover, the sensor apparatus disclosed by patent document 1, 2 detects the temperature of the cooking appliance in cooking, and stops supply of gas with a magnet and a reed switch. Therefore, the structure is complicated, and assembly of the components has the same drawbacks as described above. Further, Patent Document 3 also has a problem that the structure is complicated and expensive as described above, and the operation is not stable due to a decrease in magnetic force due to heat.

  The present invention has been made in view of the above-described problems of the prior art, and has a simple structure, low cost, easy assembly, no man-hours, and a gas that can accurately detect that a cooking utensil is placed. An object is to provide a sensor for a table.

  The present invention is a gas table sensor for detecting that a cooking utensil is placed on a gas table, wherein the abutting portion abuts on the cooking utensil and is elastically biased so as to be movable by placing the cooking utensil. A conduit connected to the contact portion, an interlocking member such as a cable inserted through the conduit and connected to the contact portion, a magnetic body fixed at an appropriate position of the interlocking member, and the magnetic A coil wound around the outer periphery of the conduit where the body is located, and when the abutting portion is moved by the cooking utensil, the interlocking member is interlocked to move the magnetic body inside the conduit in the coil, and cooking It is a sensor for gas tables formed so that an instrument can be detected.

  The moving width of the magnetic body is about the coil width of the coil formed on the outer periphery of the conduit. In addition, the magnetic body is positioned inside the coil on the outer periphery of the conduit in a state where the cooker is not in contact with the contact portion, and is moved along with the movement of the contact portion by placing the cooker. It is good to arrange so that it may come out to the outside of the coil.

  The coil is provided in a detection circuit of the cooker, and the detection circuit includes: an oscillation circuit that passes an alternating current through the coil; a conversion circuit that converts an inductance value of the coil into a voltage value; and A comparator for comparing an output voltage value with a predetermined threshold value, and the contact between the coil and the threshold voltage by comparing the output voltage of the conversion circuit with the threshold value from a change in the inductance value of the coil accompanying the movement of the magnetic body. It detects that the said cooking device was mounted in the part.

  According to the gas table sensor of the present invention, since a permanent magnet and a reed switch are not required, the structure is simple and the cost is low, and only the alignment of the coil and the magnetic material is not required, so that complicated alignment is not required and the number of assembly steps is reduced. It can be done. Moreover, since the detection accuracy does not change due to heat, the placement of a cooking utensil or the like can be detected stably with high accuracy.

  An embodiment of a gas table sensor according to the present invention will be described below with reference to FIGS. The gas table sensor 10 of this embodiment is attached in the vicinity of the center of a gas burner such as a gas table, and detects that a cooking utensil 12 such as a pan is placed on the gas table or the like. As shown in FIG. 1, the gas table sensor 10 of this embodiment is provided with a contact portion 14 that comes into contact with the bottom surface of the cooking utensil 12. The contact portion 14 is provided with a coil spring (not shown) inside and elastically biased upward in the protruding direction, and is attached to the L-shaped conduit 16. A non-magnetic metal pipe 16a that is inserted into the center of the bottom surface of the contact portion 14 and constitutes the conduit 16 is attached to the contact portion 14, and the contact portion 14 is formed to be movable downward about the pipe 16a. Has been. One end of a bent metal pipe 16b that is bent at a substantially right angle is inserted into and joined to the lower end of the pipe 16a that is fitted and inserted into the center of the bottom surface of the contact portion 14. Then, another pipe 16c is inserted and joined to the other end of the curved pipe 16b to form the L-shaped conduit 16.

  A coil 18 formed by winding a copper wire is provided on the outer periphery of the pipe 16c at an appropriate position. Further, a cable 20, which is an interlocking member having rigidity capable of advancing and retracting in the conduit 16, is inserted into the conduit 16, and one end is connected to the inside of the abutting portion 14, and the other end is connected to the conduit 16. It extends to the open end of the. A magnetic body 22 formed slightly longer than the width of the coil 18 is fixed to the cable 20 inside the pipe 16 c where the coil 18 is located, and is provided slidably in the conduit 16. At this time, when nothing is in contact with the contact portion 14, the magnetic body 22 is positioned in the coil 18, and when the contact portion 14 is pushed down, the magnetic body 22 is formed so as to come out of the coil 18. It is preferable.

  Next, the operation of the gas table sensor 10 will be described. As shown in FIG. 1, when the cooking utensil 12 is placed on a gas table (not shown), the contact portion 14 comes into contact with the bottom surface of the cooking utensil 12 and slides downward. At this time, the cable 20 moves in the conduit 16 in conjunction with the movement of the contact portion 14, and the magnetic body 22 fixed to the cable 20 is placed inside the coil 18 as shown in FIG. As shown in FIG. 2 (b), it moves together with the cable 20 from the positioned state in the direction of coming out of the coil 18. Then, the inductance value of the coil 18 is changed, and the placement of the cooking utensil 12 is detected by the detection circuit 24 described later.

  As shown in FIG. 3, the detection circuit 24 that detects a change in the inductance value is supplied with an alternating current signal from the oscillation circuit 26 to the coil 18, and the inductance value of the coil 18 is converted to a voltage value by the LV conversion circuit 28. Converted and detected. The detected voltage value is input to the comparator 30, and a Hi or Lo level determination is made based on the threshold value based on a predetermined threshold value of the voltage corresponding to the inductance value when the cooking utensil 12 is placed. A comparison output is made from the note 30, and it is determined whether or not the cooking utensil is placed.

  Here, the change in inductance value and the movable distance of the magnetic body 22 moving inside the coil 18 will be described. In the graph shown in FIG. 4, the vertical axis represents the inductance value L (mH), the horizontal axis represents the movable distance (mm), and the coil width is 4 mm. As shown in FIG. 4, when the magnetic body 22 comes out from the inside of the coil 18 from the state where the magnetic body 22 is located inside the coil 18, the inductance value changes according to the moving distance. When the magnetic body 22 is completely removed from the coil 18, the inductance value is reduced and the value is stabilized. For example, as shown in FIG. 4, when the movable distance is 0 to 4 mm, the inductance value changes abruptly, and if the boundary g from which the magnetic body 22 comes out from the inside of the coil 18 is passed, the inductance value is low and is almost constant thereafter. It becomes.

  According to the gas table sensor 10 of this embodiment, it is not necessary to attach a permanent magnet or a reed switch to the outer periphery of the conduit 16, and the structure is simple and the cost is low. In addition, since only the two alignments of the coil 18 and the magnetic body 22 are not required, complicated alignment is not necessary, so that assembly can be easily performed and man-hours can be reduced. Furthermore, since the detection accuracy does not change due to heat, it can be detected that the cooking utensil 12 is placed with high accuracy and stability.

  Further, since the change in inductance value is detected by the magnetic body 22 being removed from the position inside the coil 18 in the outward direction, the coil has a high inductance and a high impedance during standby, thereby reducing standby power consumption. It can be done. Further, the moving width of the magnetic body 22 is preferably as small as possible and more than the width of the coil 18, and therefore, the coil 18 is preferably as narrow as possible.

  The gas table sensor according to the present invention is not limited to the above embodiment, and the shape of the conduit is not limited to the L-shape, and the cable is formed so that it can be inserted and magnetically linked to the contact portion. Since the movable range of the body only needs to be secured, the shape of the conduit and the like can be set as appropriate. Moreover, the width of the coil can be appropriately set according to the movable range of the magnetic body. Furthermore, the shape and material of each member can be appropriately changed.

It is a schematic side view which shows the sensor for gas tables of one Embodiment of this invention. They are the partial expanded sectional view (a) which shows the state of the magnetic body located in the coil of the sensor for gas tables of this embodiment, and the partial expanded sectional view (b) which shows the state which the magnetic body pulled out from the inside of a coil. It is a block diagram which shows the detection circuit of the sensor for gas tables of this embodiment. It is a graph which shows the relationship between the inductance value of the sensor for gas tables of this embodiment, and the movable distance of a magnetic body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gas table sensor 12 Cooking utensil 14 Contact part 16 Conduit 18 Coil 20 Cable 22 Magnetic body 24 Detection circuit 26 Oscillation circuit 28 LV conversion circuit 30 Comparator

Claims (4)

  In the gas table sensor for detecting that the cooking utensil is placed on the gas table, the abutting portion that abuts on the cooking utensil and is elastically urged so as to be movable by placing the cooking utensil, and the abutting portion A conduit connected to the coupling member, an interlocking member inserted through the conduit and coupled to the abutment portion, a magnetic body fixed at an appropriate position of the interlocking member, and wound around an outer periphery of the conduit where the magnetic body is located. When the abutting portion is moved by the cooking utensil, the interlocking member is interlocked to move the magnetic body inside the conduit in the coil so that the cooking utensil can be detected. A gas table sensor.   2. The gas table sensor according to claim 1, wherein the moving width of the magnetic body is about the coil width of the coil formed on the outer periphery of the conduit.   The magnetic body is positioned inside the coil on the outer periphery of the conduit in a state where the cooker is not in contact with the contact portion, and the coil is moved along with the movement of the contact portion by placing the cooker. The gas table sensor according to claim 1, wherein the gas table sensor is arranged so as to come out of the outer side of the gas table. The coil is provided in a detection circuit of the cooker, and the detection circuit includes an oscillation circuit that passes an alternating current through the coil, a conversion circuit that converts an inductance value of the coil into a voltage value, and an output of the conversion circuit. A comparator that compares a voltage value with a predetermined threshold value, and from the variation of the inductance value of the coil that accompanies the movement of the magnetic body, the comparison between the output voltage of the conversion circuit and the threshold value causes the contact portion to 4. The gas table sensor according to claim 1, wherein it detects that the cooking device is placed.

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