JPS591622Y2 - Magnetic temperature sensing switch for boiler - Google Patents

Description

[Detailed description of the invention] The present invention relates to a magnetic temperature sensing switch for boilers that uses a temperature sensing member having a magnetic transformation point, such as a magnetic shunt material. Magnetic temperature sensing for boilers that allows for the common use of one type of parts, as well as ease of manufacture and assembly as each component does not require strict dimensional accuracy. There is a switch to provide.

An embodiment in which the present invention is applied to a rice cooker will be described below with reference to the drawings.

1 is a substantially cylindrical outer case with a bottom plate 2 fixed to the lower end;
3 is an annular decorative frame fixed to the upper end of the outer case 1;
5 is an inner case arranged inside the outer case 1 by placing the flange portion 4a formed at the upper end on the stepped portion 3a of the decorative frame 3; 5 is the inner case between the outer case 1 and the inner case 4; 6 is a substantially annular sheathed heater disposed at the inner bottom of the inner case 4; 7 is a heat insulating material disposed at the inner bottom of the inner case 4; 8 is an inner lid that closes the pot 7, and 9 is an outer lid that closes the outer case 1.

Now, 10 is a magnetic temperature sensing switch, which will be described in detail below.

Reference numeral 11 denotes a bottomed cylindrical protective case made of aluminum, for example, with an open lower surface, and a magnetic body 12 made of a magnetic shunt material as a temperature-sensitive member is adhered to the inner surface of this case.

The protective case 11 protrudes upward from an opening 13a of a heat shield cylinder 13 formed in the center of the inner case 4, and is provided with a support fixed to the lower surface of the inner case 4. A compression spring 15 disposed between the plate 14 and the protective case 11 constantly urges the plate 14 upward and presses it against the bottom surface of the pot 7.

Note that the spring receiver formed at the lower end of the protective case 11 is a flange, and the spring holder 11b is formed to have a larger diameter than the opening 13a.
The protective case 11 is prevented from being removed upward when the pot 7 is removed.

Reference numeral 16 denotes a movable member disposed to vertically penetrate the hole 14a of the support plate 14, and a neck portion 16 formed at the upper end.
A substantially disk-shaped permanent magnet 17 is screwed and fixed to a.

The permanent magnet 17 has an outer diameter slightly smaller than the inner diameter of the protective case 11, and is supported within the protective case 11 so as to be able to move upward.

On the other hand, 18 is a large-diameter circular flange formed at the lower end of the moving member 16.

Reference numeral 19 denotes a switch mounting plate serving as a base frame, one end of which is fixed to the outer case 1 with screws, and a tongue piece 19a in the middle.
protrudes downward.

Reference numeral 20 denotes an operating lever having a knob 21 formed, for example, by an integral mold of plastic, at one end, and a tongue portion 20a projecting upwardly at the middle portion is rotatable via a pin 22 to tongue portion 19a. is supported by

23 is a microswitch fixed to the other end of the switch mounting plate 19, which connects the operator 23a to the operating lever 20.
It is oriented downward so as to face it.

24 is a fitting hole formed at the other end of the operating lever 20;
This is formed in the shape of a long hole that is long in the direction approaching and away from the pin 22 which is the center of rotation of the operating lever 20, and the length dimension A is set to 40 mm, for example, and the width dimension B is the axis of the circular collar part 18. The diameter is set to be slightly larger than the outer diameter B' of the portion 18a.

Then, this fitting hole 24 is inserted into the shaft portion 18a of the moving member 16.
The operating lever 20 is connected to the movable member 16 by fitting the circular nut 18b into a threaded portion (not shown) formed at the lower end of the shaft portion 18a. The distance C' from the nut 18b is set to be considerably wider than the corresponding thickness C of the other end of the operating lever 20, so that the two are in a loosely fitted state. The moving member 16 does not receive any rotational force due to the rotation.

A torsion coil spring 25 is wound around the pin 22, and this applies rotational force to the operating lever 20 in the direction of arrow a.

Note that the knob 21 of the operating lever 20 projects outward from a hole 26 a of an operating panel 26 fixed to the outer surface of the outer case 1 .

Next, the operation of this embodiment configured as above will be explained.

After putting rice and water in the pot 7 and closing the inner lid 8 and outer lid 9, when the operating lever 20 is rotated in the opposite direction of arrow a using the knob 21 against the torsion coil spring 25, the moving member 16 is moved upward, and the permanent magnet 17 is attracted and held by the magnetic body 12.

Then, as the operating lever 20 is rotated in the direction opposite to the arrow a, the operating element 23a is pressed, thereby closing the microswitch 23 and energizing the sheathed heater 6.

Now, when the seed heater 6 is energized and generates heat, the pot 7 is heated and the rice is cooked. However, when all the water in the pot 7 is absorbed by the rice and the rice becomes dry, the temperature at the bottom of the pot 7 increases. The temperature starts to rise rapidly from 100°C.

Then, the magnetic body 12 pressed against the pot 7 through the protective case 11 follows the temperature of the pot 7 and increases in temperature, reaching a magnetic transformation point and becoming non-magnetic. The adsorption force acting between the torsion coil spring 25 becomes lower than the rotational force of the torsion coil spring 25.

Therefore, the spring coil of the operating lever 20 is rotated back in the direction of arrow a by the spring force of the spring 25, and the micro switch 23 is opened when the pressure of the operating element 23a is released, and the sheathed heater 6 is cut off. Ru.

By the way, in conventional rice cookers, the other end of the operating lever is bent upward to form a rising part, and a permanent magnet is screwed to the upper end of this rising part. Because the horizontal distance between the center and the permanent magnet is fixed, separate operating levers must be manufactured for two types of rice cookers with different pot diameters, making it difficult to standardize parts. Met.

In addition, in order to attract a permanent magnet to a magnetic material over a wide area without tilting, it is necessary to strictly adjust the orientation direction of the rising part formed on the operating lever and the mounting surface of the permanent magnet at the upper end of the rising part. It is very troublesome to manufacture, and it is necessary to be very careful not to deform the operating lever during assembly, making manufacturing and assembly troublesome in general.

However, in this embodiment, the fitting hole 24 is connected to the operating lever 2.
Since it is formed in the shape of a long hole having a predetermined length in the direction toward and away from the center of rotation of the control lever 20, for example, the diameter of the pot 7 is different, and the horizontal distance between the center of rotation of the operating lever 20 and the permanent magnet 17 is different. It becomes possible to use the operating lever 20 formed in the same size for two different types of rice cookers, and it is possible to share parts.

Further, since the shaft portion 18 a of the moving member 16 is loosely fitted into the fitting hole 24 of the operating lever 20 , the permanent magnet 17 attached to the moving member 16 can be easily attached to the magnetic body 1 .
Since the movable member 16, which corresponds to the rising portion of the conventional structure, is loosely fitted to the operating lever 20, manufacturing and assembling the two members is extremely simple.

In addition to the magnetic shunt material, ferrite having a magnetic transformation point may be used as the temperature-sensitive member.

As explained above, the present invention is based on a magnetic type boiler that allows the use of one type of parts in common for models with different dimensions, allows common parts, and is easy to manufacture and assemble. Temperature sensing switch can be provided.

[Brief explanation of drawings]

The drawings show an embodiment in which the present invention is applied to a rice cooker, and FIG. 1 is a longitudinal sectional view, and FIG. 2 is an enlarged perspective view of the main parts. In the drawing, 6 is a sheathed heater, 7 is a pot, 10 is a magnetic temperature sensing switch, 12 is a magnetic body (temperature sensing member), 16 is a moving member, 17 is a permanent magnet, 18 a is a shaft, and 19 is a switch mounting A plate (base frame), 20 is an operating lever, 23 is a micro switch, and 24 is a fitting hole.

Claims (1)

[Scope of utility model registration request] In a boiler equipped with a heater on a base frame, a temperature-sensitive member having a magnetic transformation point provided so as to come into contact with a detection part of a container heated by the heater, and a temperature-sensitive member rotatably provided on the base frame. An operating lever having an operating knob at one end and an elongated fitting hole oriented at the other end toward and away from the center of rotation of the operating lever; and the fitting hole of the operating lever. a movable member that is fitted in a loosely fitted state so as to approach and move away from the temperature-sensitive member as the operating lever rotates, and includes a permanent magnet that attracts the temperature-sensitive member; A magnetic temperature sensing switch for a boiler, comprising a switch device for controlling energization/disconnection of the heater based on the movement of the heater.