JPH0247371Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Purpose of the invention (field of industrial application) This invention relates to an improvement of a cooking start switch for a microwave oven.

(Prior Art) In a microwave oven, it is dangerous if electromagnetic waves for cooking flow when the door is opened, so a safety device is provided in the double structure. One is the door switch, which is generally turned off when the door opens.
The other was a relay switch consisting of a monitor relay that was energized when the door switch was closed due to a failure, and a relay contact corresponding to the monitor relay.

However, the cost of the other relay switch is very high, and there has been a desire for a switch that is low in cost and has a structure that reliably performs its safety function.

(Problems to be solved by the invention) This invention was made in view of the above points, and provides a cooking start switch that is low in cost and has excellent safety performance and incorporates a microwave oven safety device in a simple configuration. It is something to do.

(b) Structure of the device In this device, the cooking start switch is composed of three contact elements, one of which is a safety device, and has two contacts. This is a cooking start switch for the microwave oven that is linked to the operation, and the first contact element moves back and forth in conjunction with the operation of the cooking button, and when the first contact element moves in one direction based on the ON operation of the cooking button. a second contact element whose one end is connected to the first contact element, and the other end of the second contact element is always fitted and connected, and the first contact element is welded to the second contact element, and the first contact element is welded to the second contact element. When the second contact element separates from the inside due to the movement of the contact element in the other direction based on the OFF operation of the cooking button, it returns to the fitted state again and prevents the connection from being reconnected. This is a cooking start switch for a microwave oven, comprising a third contact element including a blocking part.

(Example) First, prior to explaining the cooking start switch of this invention, the configuration of a microwave oven using the cooking start switch of this invention will be briefly explained with reference to FIG.

The microwave oven 1 has a heating chamber 2 inside, and a door 3 is attached to the front surface of the heating chamber 2. Reference numeral 4 denotes an operation panel, which has two cooking tips 5 provided at the top, and upper and lower cooking buttons 6 and a door opening button 7 provided at the bottom.

Figure 2 shows the circuit configuration, where 8 is an electromagnetic wave generating section;
9 is a timer, 10 is a contact corresponding to the timer 9, 11 is a fan motor, and a door switch 13 and a cooking start switch 14 are arranged in series between a power source 12 and an electromagnetic wave generating section 8. In this configuration, electromagnetic waves are not generated from the electromagnetic wave generating section 8 unless both the door switch 13 and the cooking start switch 14 are turned on.

The structure and operation of the cooking start switch of this invention will be explained below with reference to FIGS. 3A, B to 5A, B.

The cooking start switch 14 is provided at the rear of the cooking button 6, and is divided into two parts, which are integrated with the operating plate 15 of the cooking button 6 from the front and perform reciprocating motion in conjunction with the operation of the cooking button 6. The first contact element 16 and the elastic rear part 17 are expanded and the first
Two second contact elements 18 whose one end connects to the first contact element when the contact element 16 moves in the direction of arrow A based on the ON operation of the cooking button, and a rear part 17 of each second contact element. A third contact element 21 is provided with a stopper wall 20 which is opened at the front part 9 so as to be always fitted into the third contact element 21.

In the state shown in FIG. 3, the lever 22 is in the open state.
The cooking button 6 cannot be pushed in due to the presence of the button. When the door 3 is closed, the lever 22 rotates in conjunction with the door 3, and as shown in FIG. 4, the cooking button 6 can be pressed to start cooking. When the cooking button 6 is pushed in, the lever 23 engages with a portion of the operating plate 15 as shown in FIG. 4, and the pushed state is maintained. Then, with the cooking button 6 pressed in, the first contact element 16 moves rearward and connects to the second contact element 18. Second
Since the contact element 18 and the third contact element 21 are always kept in the ON state, when the cooking button 6 is pushed in, the first, second and third contact elements are connected and cooking starts. Switch 14 is entirely
It becomes ON. The contacts constituted by the second contact element 18 and the third contact element 21 described above serve as a safety device.

When the door cooking button 7 is pressed after cooking is completed, the lever 23 moves and normally moves to the first position as shown in Fig. 3.
Contact element 16 and second contact element 18 are separated. However, if a large current flows during cooking, the first contact element 16 and the second contact element 18 will be welded together as shown in FIG.
is pulled out integrally with the first contact element 16, and at this time, the second contact element 18 is pulled out from the third contact element 2.
1, the second contact element 18 and the third contact element 21 are disconnected from each other. That is, in this state, the cooking start switch 14 as a whole
It becomes OFF.

When the door 3 is closed, even if an attempt is made to press the cooking button 6 again, the rear part 17 of the second contact element 18 comes into contact with the stopper wall 20 of the third contact element 21, and the cooking button 6 cannot be pressed in. , the third contact element 21 is prevented from fitting into the second contact element 18, and the connection is prevented. That is, the stopper wall 20 is a reconnection prevention part. To restore the normal state, check the circuit, remove the weld between the first contact element 16 and the second contact element 18, and remove the weld from the stopper wall 2.
0 is once released and the third contact element 21 is fitted onto the rear part 17 of the second contact element 18.

In the above embodiment, the stopper wall 20 is shown as the reconnection prevention part, but the second contact element 18
The third contact element 21 may have any suitable shape as long as it reliably fulfills the function of preventing reconnection between the third contact element 21 and the third contact element 21.

(c) Effects of the invention This invention is constructed as described above, and is a cooking start switch that has a simple structure and is integrated with a safety device that operates reliably. If used, a microwave oven with low production costs and excellent safety performance can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the external appearance of a microwave oven using this invention, Fig. 2 is an embodiment circuit diagram, and Figs. 3A, B to 5A, B are respective cooking start switches of this invention. FIG. 7 is a vertical cross-sectional view and a corresponding plan view showing different states. 6... Cooking button, 14... Cooking start switch, 16... First contact element, 18... Second contact element, 20... Stopper wall (reconnection prevention part), 2
1...Third contact element.

Claims (1)

[Scope of utility model registration request] This is a cooking start switch for a microwave oven that is linked to the operation of the cooking button, and includes a first contact element that moves back and forth in conjunction with the operation of the cooking button, and a first contact element that moves in one direction based on the ON operation of the cooking button. A second contact element whose one end connects to the first contact element when moved, and a second contact element which is always fitted and connected to the other end of the second contact element, and furthermore, the first contact element is welded to the second contact element. when the first contact element is on the cooking button.
A third member comprising a reconnection prevention portion that returns to the fitted state and prevents connection when the second contact element is detached from the inside due to movement in the other direction based on the OFF operation. A cooking start switch for a microwave oven consisting of a contact element.