JPS5830003Y2 - heat sensitive switch - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heat-sensitive switch used in cooking appliances such as gas automatic rice cookers.

A heat-sensitive switch that uses the cue point of the ferrite by combining a ferrite whose magnetic permeability decreases as the temperature rises and a magnet is conventionally used in cooking appliances such as automatic rice cookers, but in this one, the switch connects and separates from the ferrite. The connection structure between the operating rod, which has a yoke at its upper end, and the lever that operates the gas valve, switch, etc., is conventionally shown in Figure 3 because the lever moves in an arc around the fulcrum in response to the vertical movement of the operating rod. As shown, the connection E between the actuating rod 4' and the lever 5' must have an axial play a and a radial play b.

Therefore, due to the influence of these plays a and l), the operation becomes unreliable, and since it is necessary to determine the operating position of the lever and the lower limit position of the operating rod, unreasonable force may be applied to the operating parts of the gas valve, etc. There were also drawbacks such as problems in terms of durability, such as the effect of water acting on them and causing them to break.

This invention rectifies the above-mentioned drawbacks of the conventional method by connecting the actuating rod and lever using a flexible shaft such as a helical spring that is hardly compressible. I will explain it together.

In the drawing, 1 is a ferrite fixed to the lower surface of a heat-sensitive plate 8 made of a non-magnetic material that comes into elastic contact with the bottom surface of the container due to the elastic force of the spring 7 when a heated container such as a rice cooker is placed. Uses soft ferrite, etc., which has the property of decreasing magnetic flux.

A ring-shaped permanent magnet 2 is magnetized in the axial direction and is fixed to the lower surface of the ferrite 1.

Reference numeral 3 denotes a soft magnetic yoke which is fitted into a non-magnetic guide tube 9 inserted into the center of a permanent magnet and can be freely slid up and down, and an operating rod 4 is integrally connected to the lower center of the yoke. .

The lower end of the operating rod 4 and the tip of a lever 5 that operates a gas valve, switch, etc. of a gas automatic rice cooker are connected by a helical spring 6 that itself is not compressible. The vertical movement of the lever 5 can be accurately transmitted to the lever 5 without interfering with the arc movement.

10 is a magnet support plate, and 11 is a guide cylinder holder.

In the above embodiment, a helical spring, which itself is not compressible, was used for the flexible shaft, but it is free to use a solid cylinder made of an elastic material such as rubber, etc. .

Since this device is constructed as described above, when a container to be heated such as a rice cooker is placed on the top surface of the heat-sensitive plate 8, the operation knob (not shown) is pressed down to turn on the heat source and the lever 5 is raised. is transmitted to the actuating rod 4 via the flexible shaft 6, and the yoke 3 connected to its upper end is made of ferrite 1.
Keep it secret.

At this time, since the temperature is still low, the magnetic field of the permanent magnet 2 is formed through the ferrite 1, and the yoke 3 is formed through the ferrite 1.
is held in close contact with the

When the temperature of the heating plate 8 rises and the temperature of the ferrite 1 reaches that point, the magnetic permeability drops rapidly and the yoke 3 separates from the ferrite 1 and falls.

In order to assist this separation, a resilient force such as a spring (not shown) may be used.

Since the actuating rod 4 and the lever 5 are connected by the flexible shaft 6, the lever interlocks with the actuating rod without play, and the vertical movement of the actuating rod is accurately and immediately transmitted to the lever. This allows switches, etc. to operate accurately.

As explained above, this idea consists of ferrite 1 and magnet 2.
In a heat-sensitive switch that combines the following, the operating rod and the lever that operates the gas valve, switch, etc. are connected by a flexible shaft that itself is hardly compressible, so the operation of the gas valve, switch, etc. is accurate and quick. Furthermore, durability is improved because no excessive force is applied to operating parts such as gas valves.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of this invention during adsorption, FIG. 2 is a cross-sectional view when detached, and FIG. 3 is a cross-sectional view showing a conventional example. 1... Ferrite, 2... Magnet, 3.
...Yoke, 4...Operating rod, 5...
...Lever, 6...Flexible shaft.

Claims (1)

[Scope of utility model registration request] A heat-sensitive switch combining a ferrite 1 and a magnet 2 is characterized in that an operating rod 4 having a yoke 3 at the upper end and a lever 5 for operating gas valves, switches, etc. are connected via a flexible shaft 6. Heat sensitive switch.