JPH0310850B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a safety device for a high-frequency heating device.

Structure of the conventional example and its problems As shown in Fig. 1, the safety device of the conventional high-frequency heating device is a door key attached to the door 1 and pulled downward by a spring 2 when the door 1 is closed. 3, by pushing down the metal lever 6 supported by the lever shaft 5 on the hook 4, the actuator 9 of the micro switch 8 fixed to the frame 7 with machine screws 10 is pushed, and the micro switch 8 is operated. It had a structure that made it possible to do so. Since the operating parts were made up of several parts, there were many problems with malfunctions. Further, the lever 6 is a rigid body made of sheet metal,
Due to the low cushioning properties, the impact force when closing the door 1 is directly applied to the micro switch 8, causing damage to the actuator 9, contact springs, etc. of the micro switch 8, or causing significant changes in operating force due to wear and tear. There was a problem that shortened its lifespan.

In addition, in the control circuit shown in FIG. 2, as one of the safety devices for the power transformer 11 that forms the oscillation circuit of the high-frequency heating device, a micro switch 12, which is linked to the opening and closing of the door for loading and unloading the heated object at the front of the heating chamber, is installed.
13 has an abnormality due to contact welding or the like and is fired, a micro switch 8 that is turned on when the door opens is provided before supplying power to the power transformer 11 that generates radio waves.
A large current flows through the short circuit formed by 2 and 13, blowing out the fuse 14, and no current is supplied to the magnetron.

Therefore, at least three micro switches 8, 12, and 13 are required to operate in conjunction with the opening and closing of the door.
Therefore, three safety device mechanisms shown in FIG. 1 are required. However, this safety device mechanism has the problem of shortening the lifespan of each of the microswitches 8, 12, and 13.

Next, FIG. 3 shows another conventional safety device that improves the above-mentioned drawbacks.

In FIG. 3, the door 1 is closed, the lever 6 is pushed by the door key 3, and the micro switch 8 is turned on.

In FIG. 3, a hook 4, a switch lever 6 made of resin, and a switch fixing part 11 fixing a micro switch 8 are integrally molded from resin, and the micro switch 8 is fitted into the hook 4. The lever 6 uses the support part A as a fulcrum, and the switch operation part B operates the actuator 9 of the micro switch 8.
, and press the head C with the door key 3. As a result, the door key 3 only requires about 70% of the load required to operate the micro switch 8, making operation easier.

When an attempt is made to open the door 1, the door key 3 moves upward as indicated by the dotted line, and when the door 1 leaves the door, the resin switch lever 6 moves as indicated by the dotted line and the micro switch 8 is turned off. Next, the shape of the switch lever 6 will be described with reference to FIG. A thin wall D is formed in the vicinity of the fulcrum A, and after passing under the bend, it branches into a lever head C that comes into contact with the door key 3 and an operating part B that pushes the actuator 9 of the micro switch 8. Therefore, the movement of the door key 3 is transmitted to a certain extent, but if it is pressed beyond a certain amount of movement, it will reach the branch point G.
There is a thin part on the head lever C side near the
Furthermore, since the lever of the head C can be moved, the impact on the actuator 9 is small, and the durability of the microswitch is improved.

In addition, since the thin wall portion is provided in areas other than the vicinity of the fulcrum A, the amount of movement of the thin wall portion D near the fulcrum A is also small.
Furthermore, the amount of movement of the thin wall portion H is also small. As a result, the flexibility of the switch lever 6 to repeatedly open and close the door 1 can be significantly improved. Further, by providing both thin wall portions D and H, the durability, restorability, and creep characteristics of the switch lever 6 itself are improved.

Next, the operation of the other microswitch 12 will be described based on FIG.

In FIG. 3, the switch fixing part 15 that fixes the hook 4 and the micro switch 12, and the pivot axis 17 of the hook spacer 16 are integrally molded with resin, and the micro switch 12 is fitted into the switch fixing part 15. It is composed of

It is shown in FIG. 5, which is a sectional view taken along line A-A' in FIG. 3. When the hook spacer 16 is inserted in the direction of the arrow in FIG. 5, the L-shaped protrusion 17a of the rotation center shaft 17 falls inward as shown by the dotted line, and when the hook spacer 16 is pushed in further, the hook spacer 16 is inserted as shown in FIG. is engaged with the L-shaped protrusion 17a to prevent it from falling off.

When the unit shown in FIG. 6 is fixed to the main body, it is fixed to the main body at two places: the integrally formed boss 18 and the rotation center shaft 17. Therefore, the dimensions can be stably fixed by virtue of the fact that the main body and the door 1, the door key 3 and the hook 4, and the door key 3 and the hook spacer 16 are each integrally molded, and the rotation center axis 17 also serves as a boss for fixing the main body. It is. However, there are limits to further simplifying the current simplified safety equipment.

OBJECT OF THE INVENTION The present invention overcomes the above-mentioned conventional drawbacks.
The purpose is to further simplify the safety device, create a configuration that is highly suitable for mass production, and improve its durability.

Structure of the Invention In order to achieve the above object, the high frequency heating device of the present invention includes a door key provided on a door for opening and closing an opening of a heating chamber, a plurality of switch levers operated by the door keys, and a plurality of switch levers operated by the door keys. A hook part that appears and retracts, a plurality of microswitches that are turned on and off by the switch levers, and a switch fixing part that fixes the microswitches, the plurality of switch levers, the hook part,
It has a safety device that is integrally formed with a plurality of switch fixing parts using resin. The safety device is constructed by simply fitting the necessary microswitches into an integrally molded resin molded product, and has the advantage of being highly mass-producible and having excellent durability.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 7, the door 21 is closed and the door key 2 is closed.
2, the switch lever 23 is pushed and the micro switch 8 is turned on. Further, the switch fixing part 25 that fixes the hook 26, the switch lever 23, and the micro switch 8 is integrally molded with resin, and the micro switch 8 is fitted into the switch fixing part 25. The switch lever 23 has a support part A as a fulcrum, a switch operating part B that pushes the actuator 9 of the micro switch 8, and a head C that is pushed by the door key 22. As a result, the door key 22 only requires about 70% of the load required to operate the micro switch 8, making operation easier.

When you try to open the door 21, the dotted door key 22
The door 21 moves upward, and the switch lever 23 moves as shown by the dotted line, and the switch 8 turns off.

Next, the shape of the switch lever 23 will be described with reference to FIG. 8a. Thin wall D near fulcrum A part
After passing through the bent part F, the door key 22
The lever head C that comes into contact with the micro switch 8
It branches into an operation part B that pushes the actuator 9. Therefore, the movement of the door key 22 is transmitted to a certain extent, but if the door key 22 is pushed beyond a certain amount of movement, the lever on the head C will move further because there is a thin section on the head lever C side near the branching point G. Therefore, there is less impact on the actuator 9, and the durability of the microswitch is improved.

In addition, since the thin wall portion is provided in areas other than the vicinity of the fulcrum A, the amount of movement of the thin wall portion D near the fulcrum A is also small.
Furthermore, the amount of movement of the thin wall portion H was also reduced. As a result, the repeated flexibility of the resin lever 23 when opening and closing the door 21 was significantly improved. In addition, by providing the thin parts D and H, the switch lever 2
The durability, resilience, and creep characteristics of 3 itself have been improved.

In FIG. 7, a switch fixing part 27 that fixes the hook 26 and the micro switch 12, and a switch lever 28 are integrally molded from resin, and the micro switch 12 is fitted into the switch fixing part 27 and the switch lever 28, respectively. The switch lever 28 uses the support part K as a fulcrum,
The actuator of the micro switch 12 is pressed with the switch operation portion L, and the L portion of the switch operation portion is pressed with the door key 22.

When you try to open the door 21, the dotted door key 22
The door 21 moves upward, and the switch lever 28 becomes as shown by the dotted line, and the micro switch 12 is turned off.

Next, the switch lever 28 will be described with reference to FIG. 8b. A thin wall M portion is formed near the fulcrum K portion, past the bent portions P and Q, and next to the thin wall portion R.
On the back side of the surface that comes into contact with the door key 22, there is an operation part L that pushes the actuator of the micro switch 12. Since the thin portions are provided in areas other than the vicinity of the fulcrum K, the amount of movement of the thin portion M near the fulcrum K is also small, and the amount of movement of the thin portion R is also reduced. This made it possible to significantly improve the flexibility of the switch lever 28 over repeated opening and closing of the door 21. Furthermore, by providing both thin-walled portions M and R, the durability, restorability, and creep characteristics of the switch lever 28 itself are improved.

Therefore, by simply fitting the micro switches 8, 12, the hook 26, switch levers 8, 12,
As the switch fixing parts 25 and 27 are assembled,
It can be used for temporary stocking and checking the operation of microswitches, making it a unit that can be mass-produced.

When the unit shown in FIG. 9 is fixed to the main body, the integrally formed bosses 29 and 30 are fixed to the main body. Therefore, the main body and the door 21, the door key 22 and the hook 26, and the door key 22 and the switch levers 23 and 28 are stably fixed.

As described above, the hook 26, the plurality of switch levers 23, 28, and the plurality of switch fixing parts 2
5, 27, mounting bosses 29, 30, etc. are integrally molded with resin, and the micro switches 8, 12 are sandwiched between them, so the structure is simple and easy to assemble.
This has the effect of making it possible to create a safety device that operates reliably, is inexpensive, and has good durability.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) By integrating the resin, it has a double insulation structure.

(2) The number of components is made up of a plurality of microswitches, a plurality of switch levers, a hook portion, and a plurality of switch fixing portions integrally formed with resin, which provides extremely good workability and can be manufactured at low cost.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts showing the safety device of a conventional high-frequency heating device, Figure 2 is a control circuit diagram of the high-frequency heating device, and Figure 3 is the main part showing the safety device of another conventional high-frequency heating device. 4 is an external perspective view of the switch lever of the same device shown in FIG. 3, and FIG.
6 is a perspective view of the main part of the same device shown in FIG. 3, and FIG. 7 is a sectional view of the main part showing the safety device of the high-frequency heating device according to an embodiment of the present invention.
8 is an external perspective view of a lever of the safety device shown in FIG. 7, and FIG. 9 is an external perspective view of a main part of the same device shown in FIG. 7, which is an embodiment of the present invention. 8, 12, 13...Micro switch, 21...
...Door, 22...Door key, 23, 28...Switch lever, 25, 27...Switch fixing part, 2
6... Futsuku.

Claims (1)

[Claims] 1. A door key provided on the door that opens and closes the front opening of the heating chamber, a plurality of switch levers that are operated by the door key, a hook portion on which the door key appears, and a door that is turned on and off by the switch lever. and a switch fixing part for fixing the microswitches, the plurality of switch levers, the hook part, and the plurality of switch fixing parts are integrally formed of resin, and the switch levers are fixed. At least one of the switches is branched into a head that contacts the door key and an operating section that operates a micro switch, and among the plurality of switches, at least one is a switch that opens and closes the main circuit, and at least one of the switches is a main circuit open/close switch that is a contact point. A high-frequency heating device configured with a switch that is turned on when the door is opened before power is supplied to the power transformer that generates radio waves in the event of an abnormality such as welding.