JPS6135124Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an electric cooker.

In general, for electric cookers that use a mechanical thermostat to control the fermentation temperature, if multiple heaters are connected in parallel and energized as in the case of high temperature control (100°C to 250°C), Due to the rapid temperature rise, the thermostat's operation is delayed, causing the following problems.

Since the first rising peak exceeds the set temperature and becomes too high, bacteria such as yeast on the surface of the food will die or dry out, making it impossible to expect satisfactory fermentation.

Since the on/off range of the thermostat is further expanded as the temperature inside the refrigerator, it is difficult to obtain a predetermined temperature.

Therefore, an electric cooker has been proposed in which a plurality of heaters are connected in series to reduce power consumption and slow the rise in internal temperature. This conventional electric cooking device will be explained using FIG. 1 and FIG. 2. To energize the upper and lower heaters during normal use, set the heater switching knob 1 to the "vertical" position. As a result, the electrical connection becomes as shown in Figure 1A,
The parallel circuit of the upper heater 2 and lower heater 3 is energized. The temperature inside the refrigerator is set by the temperature control knob 4, and during fermentation cooking, by setting both the heater switching knob 1 and the temperature control knob 4 to the "fermentation" position as shown in FIG. The electrical connection is as shown in FIG. 2, and the series circuit of the upper heater 2 and lower heater 3 is energized to obtain the fermentation temperature. When the heater switching knob 1 is set to the "up" position, the electrical connection is made as shown in Figure 1B, and the upper heater 2 is energized, and when the heater switching knob 1 is set to the "down" position, the electrical connection is as shown in Figure 1C. The electrical connection is made such that the lower heater 3 is energized. However, in such an electric cooker, both the heater switching knob 1 and the temperature control knob 4 must be set to the "fermentation" position during fermentation cooking, which has the drawback of being cumbersome to operate and prone to erroneous operation.
Note that _T1 is a timer switch, _Th1 is a thermostat, _SW1 is an upper heater changeover switch, _SW2 is a lower heater changeover switch, and _SW3 is a heater series/parallel changeover switch.

In view of the above points, the present invention is easy to operate,
The purpose of the present invention is to provide an electric cooker that can reduce erroneous operations, and to achieve this purpose, in an electric cooker that has a thermostat and two heaters, the operating temperature of the thermostat is made variable. A cam is attached to the shaft, an actuator lever is swung by the cam, and the actuator lever is operated by the actuator lever.
two microswitches for switching the two heaters from a parallel connection state to a series connection state, and a step is provided at a portion of the actuator lever that contacts the push buttons of the two microswitches;
The operating timing of each microswitch is made to have a time difference. One embodiment will be described below based on the drawings.

In FIG. 3, _T2 is a timer switch, and one end of the timer switch _T2 is connected to one end of the upper heater changeover switch _SW4 and one end of the lower heater changeover switch _SW5 , and the upper heater changeover switch SW4 is connected to one end of the upper heater changeover switch _SW4 . The other end is connected to the normally closed terminal _B1 of the micro switch _LS1 . The common terminal _C1 of the microswitch _LS1 is connected to one end of the thermostat _Th2 via the upper heater 5. The other end of the lower heater changeover switch SW ₅ is connected to the lower heater 6.
The normally closed side terminal _B2 of the micro switch LS ₂ is connected to the connection point between the upper heater 5 and one _end of the thermostat _{Th 2 .} There is. Further, the normally open side connection point _A1 of the micro switch _LS1 and the normally open side contact _A2 of the micro switch _LS2 are connected to each other, and the other end of the timer switch _T2 and the thermostat _Th2 are connected to each other. The other ends are respectively connected to both ends of a power source (not shown).

Now, assuming that the heater switching knob 7 shown in Fig. 4 is set to the "up/down" position and the temperature adjustment knob 7 is set to the "100°C" or "250°C" position, the temperature will change as shown in Fig. 3A. , upper heater selection switch SW ₄ and lower heater selection switch SW _5.
is closed, and the micro switches LS ₁ and LS ₂ surrounded by the broken line A are connected to the common terminals C ₁ and C ₂ and the normally closed terminal.
B ₁ and B ₂ are in a short-circuited state, and the parallel circuit of the upper heater 5 and lower heater 6 is energized. When the temperature inside the refrigerator reaches the temperature set on the temperature control knob 8, the thermostat _Th2 is opened, and the power supply to the parallel circuit of the upper heater 5 and the lower heater 6 is cut off. When the temperature inside the refrigerator falls to a certain level determined by the characteristics of the thermostat _Th2 , the thermostat _Th2 is closed again, and the parallel circuit of the upper heater 5 and the lower heater 6 is energized. When the time set in timer switch T ₂ has elapsed, the timer switch T ₂
The above operation is repeated until it is opened.

When the heater switching knob 7 is switched to the "up" position, the lower heater switching switch SW ₅ is turned on as shown in Figure 3B.
is opened and only the upper heater 5 is energized, and when the heater switching knob 7 is switched to the "down" position, the upper heater switching switch SW ₄ is opened and only the lower heater 6 is energized, as shown in FIG. 3C. Ru.

Furthermore, when the heater switching knob 7 is set to the "up/down" position, which is the normal operating state, and the temperature control knob 8 is switched to the "fermentation" position, the thermostat shaft 9 shown in FIG. 5 rotates counterclockwise. Then, the push buttons PB ₁ , _{PB 2 of} the micro switches LS 1 , LS ₂ are pushed by the cam 10 attached to the thermostat shaft 9 via the actuator lever 11 . Although the micro switch LS ₂ is not shown in the drawing, it is installed in parallel with the micro switch LS ₁ , and one actuator lever 11 is used to control the push buttons PB ₁ and LS ₂ of both micro switches LS 1 and LS ₂ .
PB ₂ is configured to be pressed. Therefore, as shown in FIG. 3D, the micro switches LS ₁ and LS ₂ are in a state where the common terminals C ₁ and C ₂ and the normally open side terminals A ₁ and A ₂ are short-circuited, and the upper heater 5 and the lower heater 6 The fermentation temperature is obtained by energizing the series circuit with the

In this way, fermentation cooking is possible by switching the temperature control knob 8 to the "fermentation" position while keeping the heater switching knob 7 in the "up/down" position, which is the normal usage state. 7, and the operation is simple. This also prevents erroneous operations, such as switching only the temperature control knob 4 to the "fermentation" position and performing fermentation cooking without switching the heater switching knob 1 to the "fermentation" position, as in conventional electric cookers. be able to. In this embodiment, when the temperature control knob 8 is switched to the "fermentation" position while the heater switching knob 7 is set to the "up" position, the upper heater 5 and the lower heater 6 are not energized, but during normal cooking, the heater Since the switching knob 7 is set to the "up/down" position, there is no problem.

By the way, when the temperature control knob 4 is switched to the "fermentation" position with the heater switching knob 7 set to the "up/down" position, the contact spacing between the micro switches LS ₁ and LS ₂ is smaller than that of a general switch, so arcing may occur. There is a possibility that a short circuit may occur as shown by arrows B and C in Figure 3D. This short circuit time is 10m
Since the time is within sec and the time is short, the home breaker will not trip, but if this condition continues, it will cause about 100%
Problems such as welding of contacts occur after about 30 times. As mentioned above, the arc of micro switches LS ₁ and LS ₂ is considered to last within a half wave of the commercial frequency (within 10 msec), so if the switching timing of micro switches LS ₁ and LS ₂ is shifted by 10 msec or more, a short circuit will not occur. There will be no.

Here, the distance difference between the switching points of the microswitches LS ₁ and LS ₂ where the switching timing difference is 10 msec or more will be explained using FIG. First, the temperature control knob 8 is switched from the "100°C" position to the "fermentation" position about 200 times/minute if done quickly. If the radius of the cam 10 is r and the angle of movement of the temperature control knob 8 from the "100°C" position to the "fermentation" position is 90°, then the rotational speed of the cam 10 is 90/360 x 200 x 2πr/min = 100πr /minute. However, since the above calculation is an average, the rotation speed of the cam 10 at the position where the actuator lever 11 is pressed is considered to be twice that, so 2×100πr/min=200πr/min. Also, the speed at which the actuator lever 11 is pushed is approximately 1/2 from the vector analysis, so 1/2 x 200πr/min = 100πr/min, and in the end, the speed at which the actuator lever 11 is pushed by the cam 10 is 100πr/min. . Here, the distance from the center of rotation of the actuator lever 11 to the contact point between the actuator lever 11 and the cam 10 is a, and the distance from the center of rotation of the actuator lever 11 to the push of the actuator lever 11 and the micro switch LS ₁ is a. If the distance to the point of contact with the button PB ₁ is b, then the speed at which the actuator lever 11 presses the push button PB ₁ of the micro switch LS ₁ is Here, if a/b=2 and r is 12.5 mm, the speed at which the actuator lever 11 presses the push button PB ₁ of the micro switch LL ₁ is approximately 0.3 mm/10 msec. Therefore, there is a gap of 0.3 mm between the contact part of the actuator lever 11 with the push button PB ₁ of the micro switch LS ₁ and the contact part of the actuator lever 11 with the push button PB ₂ of the micro switch LS ₂ .
By providing a step and shifting the switching positions of the microswitches LS ₁ and LS ₂ , a time difference can be given to the timing of these operations, thereby preventing the above-mentioned short circuit. Therefore, micro switch LS ₁ ,
This significantly extends the lifespan of the LS ₂ contacts and also improves safety.

The present invention can be implemented as described above, and according to this, the switching operation between normal cooking and fermented cooking can be easily performed, and erroneous operation can be prevented. In addition, a step is provided on the actuator lever.
By shifting the switching positions of the individual microswitches, the life of the microswitch contacts can be greatly extended, and safety can be improved.

[Brief explanation of the drawing]

Figures 1A to 1D are circuit diagrams of conventional electric cookers, where A is the normal cooking state, B is the cooking state using only the upper heater, and C is the cooking state using only the lower heater. Figure 2A and B are front views of the heater switching knob and temperature control knob of a conventional electric cooker, respectively, and Figures 3 to 5 are the circuit diagram of the state during fermentation cooking. An embodiment of the invention is shown, and Figures 3A to 3D are its circuit diagrams, where A is the normal cooking state, B is the cooking state using only the upper heater, and C is the state when only the lower heater is used. Fig. 4A and B are front views of the heater switching knob and temperature control knob, respectively, and Fig. 5 is a front view of the mechanism that operates the micro switch. It is a diagram. 5... Upper heater, 6... Lower heater, 9... Thermostat shaft, 10... Cam, 11... Actuator lever, Th ₂ ... Thermostat, LS ₁ ,
LS ₂ ...Micro switch, PB ₁ , PB ₂ ...Push button.

Claims (1)

[Scope of utility model registration request] In an electric cooker having a thermostat and two heaters, a cam is attached to a shaft that changes the operating temperature of the thermostat, an actuator lever is swung by the cam, and an actuator lever is moved by the actuator lever. two microswitches that are operated by the actuator lever to switch the two heaters from a parallel connection state to a series connection state; An electric cooking device in which the two microswitches are operated at different timings.