JPS6115682B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a switch device for an electric cooker such as a so-called electric jar rice cooker, and particularly to a switch device that prevents malfunctions of the switch so that it can always operate accurately.

A general electric jar rice cooker includes a frame, an outer pot that is housed and fixed in the frame, an inner pot that can be stored in the outer pot, a heater provided at the inner bottom of the outer pot, and a heater. a heat sensitive element located in the center and always in close contact with the outer bottom of the inner pot;
It is equipped with a switch that turns on and off in conjunction with the heat-sensitive body, and is configured to heat the inner pot and cook rice.

However, in recent years, with the aim of improving rice cooking performance, the heater has been raised slightly above the inner bottom of the outer pot, and the upper peripheral flange of the inner pot has been placed on the upper peripheral flange of the outer pot. A so-called space heating type electric rice cooker has been commercialized in which a space is provided around the entire circumference of the rice cooker and the inner pot is heated using radiant heat from a heater, but as mentioned above, the flange of the inner pot is placed on the flange of the outer pot. Therefore, due to variations in the dimensions of the inner and outer pots, the spatial distance between the outer pot and the bottom of the inner pot will change, which will adversely affect the operation of the heat-sensitive element and cause problems with the ON/OFF operation of the switch when starting or finishing rice cooking. Either the rice could not be cooked, or the heater did not turn off even after the rice had finished cooking, overheating the rice more than necessary, resulting in not only burnt rice but also temperature rises in various parts, creating a risk of fire. To be more specific, the above-mentioned variations in the dimensions of the inner and outer pots are due to the fact that both the inner and outer pots are drawn from aluminum, so for example, the dimension between the upper peripheral flange of the outer pot and its bottom wall is larger than the specified dimension If the dimension between the top peripheral flange of the pot and its bottom wall is smaller than the specified dimension, the switch will not turn OFF when the rice is finished cooking.
Also, if the dimension between the upper peripheral flange of the outer pot and its bottom wall is small, and the dimension between the upper peripheral flange of the inner pot and its bottom wall is large, press the operation button to start cooking and the switch will not turn on. This phenomenon caused the rice cooker to become completely useless as a rice cooker.

The present invention improves the above-mentioned drawbacks and prevents malfunctions of the switch. The following will be explained based on an embodiment shown in the drawings. 1 is a cylindrical frame, 2 is a bottomed cylindrical outer pot that is placed inside the frame 1 and formed by drawing, and the bottom wall extends from the center side. A bulging portion 3 is formed to protrude upward, and the upper peripheral edge extends outward to form a flange 4. Reference numeral 5 denotes an exposed type rice-cooking heater installed slightly above the inner bottom of the outer pot 2, and 6 refers to a bottomed inner heater provided in the outer pot 2 so as to be freely stored and formed by drawing. The pot is formed with an outwardly extending flange 7 on its upper periphery. Reference numeral 8 denotes a heat sensitive body provided in the bulge 3 and always urged by a spring 9 so as to protrude upward, and as shown in FIG.
1, a movable member 15 consisting of a magnet 13 with an operating shaft 12 fixed in the case, and a receiving plate 14.
and a temperature-sensitive member 16 such as soft ferrite having a Curie point fixed to the inner wall surface of the upper case 10.
A spring 17 is provided between the receiving plate 14 and the upper case 10, and the spring 17 always urges the moving member 15 to move away from the temperature sensing member 16. That is, the temperature sensing member 16 is a ferromagnetic material at room temperature and allows the magnet 13 to be attracted to it, and when it reaches a predetermined temperature, it changes to a weakly magnetic material and the spring 17 releases the attraction of the magnet 13. 18 is a hook provided at the lower part of the heat sensitive element 8 to prevent it from coming off; 19
has a mounting piece 21 with a hole 20 drilled in one side of the upper part, a shaft supporting piece 23 with shaft holes 22, 22 bored in the other side of the upper part, and a stopper 24 projecting upward in the lower part.
and a support fitting having a fixing piece 26 with a mounting hole 25 bored therein; 27 is a mounting fitting provided on the outer bottom wall of the outer pot 2; Fix it to the bottom wall of outer pot 2. 28 has an operation button 29 fixed on one end and the operation shaft 12 on the other end.
It is a switch lever that is loosely connected to the lower part of the switch lever, and has pivot pieces 31, 31 with shaft holes 30, 30 bored approximately in the center, and a pusher 32 made of an insulator attached to the other end. There is. 33 is a switch that is turned on by pressing the operation button 29 at the start of rice cooking and turned off by the return operation at the end of rice cooking. It consists of a movable contact plate 35 having elastic contacts 35', insulating stands 36, 36 assembled with the respective contact plates in an insulated state, and screws 37, and a fixed piece is attached to the fixing piece through the mounting hole 25 of the support fitting 19. It is fixed at 26. Therefore, the stopper 24 and the switch 33 are integrally fixed by the screw 37 and fixed to the mounting bracket 19. Reference numeral 38 denotes a heat-retaining heater attached closely to the upper outer wall of the outer pot 2, and 39 a ring-shaped frame provided between the upper peripheral edge of the frame 1 and the flange 4 of the outer pot 2 to fix each of them. The cover 40 is a lid whose one side is rotatably supported on the frame 1 and the other side is latched, and an inner lid 41 and a heat insulation lid 42 are integrally engaged with each other and attached to the inner surface. 43 is a back cover that covers the lower part of the frame 1; 44 is a cord winding device attached to the bottom surface of the back cover 43; 45 is a switch cover provided on one side of the frame 1 and facing the operation button 29; 46 and 47 are between the frame 1 and the outer pot 2,
These are a side insulation material and a lid insulation material housed within the outer lid 40.

Next, the assembly order and operation will be described. First, the main parts of the assembly structure are fixed to the fixing piece 26 by fixing the screw 37 to the mounting hole 25 of the support fitting 19 via the switch 33 as described above. Then, the pivot pieces 31, 31 of the switch lever 28 are housed in the pivot piece 23, and the respective shaft holes 22, 22, 30, 30 are penetrated with pins (not shown) to pivot the switch lever. 28, the other end of the lever is loosely connected to the lower part of the operating shaft 12, the moving member 15 is raised by pressing the operating button 29, and the operating button 29 is pressed by lowering the moving member. I will make you return. Then, the support metal fitting 19 and the mounting metal fitting 27 are simultaneously fixed to the outer pot 2 using screws (not shown) through the hole 20 of the support metal fitting 19 and the mounting metal fitting 27. Then, the inner pot 6 is stored in the outer pot 2, the flange 7 of the inner pot 6 is placed on the flange 4 of the outer pot 2, and the inner pot 6 is placed inside the outer pot 2.
is supported in a suspended state, and a space S is formed between the bottom walls of the inner and outer pots. The heat sensitive body 8 is heated by storing the inner pot 6.
is pushed down against the elasticity of the spring 9, and in conjunction with this movement, the operating shaft 12 is moved down as shown in Fig. 3A.
descends, pushes down the other end of the switch lever 28, presses the movable terminal plate 35 with the pusher 32, and closes the contact 3.
4' and 35' are separated. At this time, the operating shaft 12
For the lowering operation, stopper 2 is placed on switch lever 28.
The moving member 15 is stopped because it is in contact with the moving member 15.
There is a gap l between the receiving plate 14 and the bottom wall of the lower case 11.
form. This gap l maintains the distance between the respective contacts at a predetermined value.

Now, when the operation button 29 is pressed and the other end of the switch lever 28 is pushed up, the pusher 32 is also raised as shown in FIG. At the same time, the moving member 15
is raised against the spring 17, and the magnet 13 is attracted to the temperature sensing member 16. At this time, the adsorption state between the temperature sensing member 16 and the magnet 13 is maintained because the temperature sensing member 16 is made of a ferromagnetic material. On the other hand, by closing the contacts 34' and 35', the heater 5 generates heat, heats the inner pot 6, and starts the rice cooking operation. Eventually, the temperature sensing member 16, which senses the sudden rise in temperature at the bottom of the inner pot after the rice has finished cooking, changes from a ferromagnetic material to a weakly magnetic material, the magnet 13 is separated, and the moving member 15 is moved downward by the spring 17. Then, as shown in FIG. 3A, the contacts 34' and 35' are opened to stop the heater 5 from generating heat.

By the way, if there is a variation in the dimension between the flanges 7 and 4 of the inner and outer pots and the bottom wall, let the dimension from the top surface of the flange 4 of the outer pot 2 to the bottom wall be A, and the flange of the inner pot 6. If the dimension from the bottom surface to the bottom wall of 7 is B, there will be an error of ± in any dimension, so
If these respective errors are a and b, the respective error ranges are A+a or A-a, and B+b or B-b.
becomes. Of course, A and B are standard dimensions. In this case, the dimension G between the bottom wall of the inner pot 6 and the bottom wall of the outer pot 2 is G
=A-B, and this dimension G takes into consideration the above-mentioned error.When dimension G is large, dimension GL is GL=(A
+a)-(B-b)>G dimension Gs when G is small
(Gs)=(A-a)-(B+b)<G.

To explain this in detail, when the dimension G is GL, when the inner pot 6 is retracted and the switch 33 is OFF, the heat sensitive element 8 is moved above the specified value by the sum of (+a) and (-b). Although it protrudes, it is absorbed by the gap l in the heat sensitive body 8, and the movable member 15 descends by an amount corresponding to (+a) and (-b), thereby reducing the gap l. That is, when the dimension G is GL larger than the specified value, the change is absorbed by the gap l in the heat sensitive element 8 becoming smaller. This is because the switch lever 28 comes into contact with the stopper 24, so the upper case 1 of the heat sensitive element 8
This is achieved by raising the temperature sensing member 16 and the lower case 11 to 0. For this reason, the contacts 34',
The distance between 35' is always maintained at the specified value by the stopper 24, and the distance between (+a)
This prevents the movable contact plate 35 from being pushed down by the sum of (-b) and increasing the distance between the contacts 34' and 35'. Also, when the dimension G is Gs, when the inner pot 6 is stored, the moving distance of the heat sensitive body 8 is smaller than the specified value by the sum of (-a) and (+b), and the distance inside the heat sensitive body 8 is reduced by this amount. It is absorbed by increasing the gap l. This means that the switch lever 28 is at the stopper 2.
This is achieved by lowering the upper case 10, the temperature sensing member 16, and the lower case 11 of the heat sensitive element 8 to come into contact with the heat sensitive member 4. Therefore, the distance between the contacts 34' and 35' is always maintained at a specified value by the stopper 24, and the distance between the contacts does not have to be increased as in the conventional case, and the pressing force of the movable contact plate 34 can be suppressed. can.

Although the present invention uses a temperature-sensitive member made of soft ferrite as the heat-sensitive body, not only soft ferrite but also bimetal or the like may be used.
In short, it is the same as long as it uses a moving member that is mechanically displaced depending on the temperature. In addition, although the heater was installed floating on the inner bottom of the outer pot, it could also be a so-called hot plate type heater with a sheathed heater cast into it. It can be anything that can be placed. The stopper does not necessarily need to be provided on the switch side; for example, it may be pressed against the top of the switch lever between the pivot point of the switch lever and the operating button, or it may be attached to the outer bottom wall of the outer pot and the stopper may be placed on the other end of the switch lever or on the operating shaft. The same goes for preventing it from lowering more than necessary.

As described above, the present invention allows the inner pot to be freely stored in the outer pot, and when the inner pot is stored, the upper periphery of the inner pot is placed on the upper periphery of the outer pot, and the heat sensitive element provided at the bottom of the outer pot is mechanically displaced by temperature. A movable member is provided, and the switch is operated in conjunction with a switch lever connected to the movable member to turn on and off the heater. Since the switch is equipped with a specified stopper, accurate ON-OFF operation can always be performed by keeping the distance between the switch contacts constant. In other words, even if the dimensions between the upper periphery and the bottom wall of the inner pot and outer pot vary greatly or small, the switch lever is regulated by the stopper and no more pressing force than necessary is applied to the contact side, making it easy to cook rice, etc. The operation can be performed accurately and scorching or undercooking can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electric cooking appliance having a switch device according to the present invention, FIG. 2 is an exploded perspective view of the main parts, and FIGS. 3A and 3B are operation explanatory views. 1... Frame, 2... Outer pot, 5... Heater, 6... Inner pot, 8... Heat sensitive element, 15... Moving member, 24... Stopper, 28... Switch lever, 29... Operation button , 33...Switch.

Claims (1)

[Claims] 1. A frame, a bottomed cylindrical outer pot built into the frame, an inner pot that can be freely stored inside the outer pot and whose upper periphery rests on the upper periphery of the outer pot when stored, and a heater; a heat sensitive body having a movable member that is provided at the bottom of the outer pot and is energized to project upward at all times and is mechanically displaced depending on the temperature; an operating button at one end and connected to the movable member at the other end; A switch for an electric cooker comprising a switch lever, a switch that operates in conjunction with the switch lever to turn on and off the heater, and a stopper that is integrally fixed with the switch lever and the switch and regulates the distance between the contacts of the switch. Device.