JPH0441433Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a fire alarm clock with an improved temperature switch section.

(Prior Art) Japanese Utility Model Publication No. 11275/1983 is known as disclosing this type of fire alarm watch.

The clock disclosed in the publication includes, in addition to the clock circuit,
Equipped with an alarm circuit in which a temperature switch using a bimetal, semiconductor sensor, temperature-sensitive ferrite, etc. is connected in series to an alarm such as a buzzer, and in the event of a fire, the alarm is activated based on the ON operation of the temperature switch. It is now possible to issue a warning.

Further, as disclosing a temperature switch of a different type from the above, there are known Utility Model Application Publications No. 56-31336 and Japanese Patent Application Laid-open No. 56-116236.

The temperature switch disclosed in the former publication consists of an outer casing having an inner chamber filled with a thermally expandable liquid or gas, a pressure-sensitive conductor made of pressure-sensitive rubber or the like disposed inside the inner chamber, and a pressure-sensitive conductor made of pressure-sensitive rubber or the like disposed inside the inner chamber. It consists of a pair of electrodes attached to the electron, and the increase in internal pressure due to temperature rise presses the pressure-sensitive conductor to reduce its electrical resistance, and conduction is established between the electrodes via the pressure-sensitive conductor. I'm trying to get it.

In addition, the temperature switch disclosed in the latter publication has a main body case containing a hydrogenated metal, a contact holding plate having a movable contact and movably arranged inside the main body case, and a contact holding plate that is in contact with the movable contact and is connected to the main body. It consists of a fixed contact placed in a case, and when hydrogen is released due to temperature rise, the contact holding plate is pushed down to separate the movable contact from the fixed contact, cutting off electrical conduction between the contacts.

(Problems to be solved by the invention) However, the above-mentioned fire alarm clock has problems with the temperature switch used in terms of cost and operation.

In other words, a temperature switch using a bimetal has poor responsiveness to a rise in temperature, and a temperature switch using a semiconductor sensor, temperature-sensitive ferrite, etc. has the disadvantage that the switch itself is expensive.

In addition, the pressure-sensitive temperature switch mentioned earlier presses the pressure-sensitive conductor by the increase in internal pressure caused by the temperature rise, reducing its electrical resistance, and creating continuity between the electrodes via the pressure-sensitive conductor. Therefore, the conduction resistance between the electrodes decreases as the pressure increases, so it cannot be said to be functionally preferable as an on-switch.

Furthermore, with the hydrogen release type temperature switch mentioned earlier, the hydrogen released due to temperature rise pushes down the contact holding plate and separates the movable contact from the fixed contact, so it turns on when the temperature rises and issues an alarm. It is not suitable for circuits that are exposed to fire, and the switch itself is expensive.

The present invention was made in view of the above circumstances, and its purpose is to provide a fire alarm clock equipped with a temperature switch that is inexpensive and operates accurately.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides the above-mentioned fire alarm clock in which a temperature switch that detects and operates the temperature at the time of a fire is connected in series to an electric alarm. The temperature switch is made of a foaming agent with a large coefficient of thermal expansion, a movable contact provided at the movable end of the foaming agent,
It consists of a movable contact and a stationary contact placed facing each other and spaced apart.

(Function) In the fire alarm watch according to the present invention, when the surrounding temperature rises above room temperature due to a fire, etc., the foaming agent in the temperature switch rapidly expands and the movable contact moves toward the fixed contact. When both contacts come into contact, the electric alarm is energized and an alarm is issued.

The temperature switch described above has a structure in which the movable contact contacts the fixed contact by thermal expansion of the foaming agent, so the movable contact is brought into contact with the fixed contact reliably and quickly by the thermal expansion of the foaming agent. It can perform its function accurately as an on-switch. Furthermore, since the number of components is small and the cost of parts is low, the switch itself can be constructed at low cost.

(Embodiment) FIG. 1 shows an alarm circuit 10 of a fire alarm clock to which the present invention is applied.

In the figure, 11 is a battery, 12 is an electric bell,
13 is a timer switch, and 14 is a temperature switch. An electric bell 12 and a timer switch 13 are connected in series to the battery 11, and a temperature switch 14 is further connected in series to the electric bell 12.

The timer switch 13 is connected to a timer (not shown), and is turned on to ring the electric bell 12 at a set time such as an alarm time. Further, this timer switch can be turned off as appropriate using a button (not shown) provided on the watch.

As shown in FIG. 2, the temperature switch 14 includes an insulating cylindrical case 1 whose one end is closed with a board 20.
5, a fixed contact 16 fixedly disposed at the other end of the case 15, a movable contact 17 movably disposed inside the case 15 facing the fixed contact, and a space between the substrate 20 and the movable contact 17. A thermally expandable foaming agent 21 is arranged.

Lead wire 1 is connected to the fixed contact 16 and the movable contact 17.
8 and 19 are connected to each other, and the foaming agent passage portion of the lead wire 19 has a sag in consideration of the expansion of the foaming agent 21.

In the embodiment, a foam coating agent called Thermocell (trade name) is used as the foaming agent 21. This foaming agent 21 starts foaming at a temperature of 60 to 80°C, which exceeds room temperature, and expands 2 to 15 times.

Here, the above-mentioned alarm circuit 10 and temperature switch 1
The operation of step 4 will be explained.

At room temperature, the fixed contact 16 of the temperature switch 14
and movable contact 17 are separated by a predetermined distance, and the switch itself is in an OFF state.

When the surrounding temperature rises above room temperature due to a fire, etc., the foaming agent 21 of the temperature switch 14 expands rapidly, causing the movable contact 17 to move toward the fixed contact 16, and when both contacts 16 and 17 come into contact, The electric bell 12 is energized and an alarm is issued.

Since the coefficient of thermal expansion of the foaming agent 21 is large and rapid, the movable contact 17 can be brought into contact with the fixed contact 16 quickly and reliably when the temperature rises as described above, and the function as an on-switch can be accurately performed.

Further, since the temperature switch 14 has a small number of components and is inexpensive, it can be constructed at a low cost to the extent that it can be used as a disposable device, and can be easily replaced.

Another embodiment of the temperature switch is shown in FIG. This temperature switch consists of fixed contacts 16A and 16B with an L-shaped cross section provided on a substrate 20, a foaming agent 21 disposed on the substrate 20 between the fixed contacts 16A and 16B, and a space between the fixed contacts 16A and 16B. A movable contact 17 in a flat plate shape is disposed on the upper surface of the foaming agent 21 so as to face each other.

Even if this temperature switch is used in place of the temperature switch 14 of the above embodiment, similar functions and effects can be obtained.

(Effects of the invention) As detailed above, according to the invention, since a temperature switch having a structure in which a movable contact is brought into contact with a fixed contact by thermal expansion of a foaming agent is used,
Thermal expansion of the foaming agent allows the movable contact to contact the fixed contact quickly and reliably, allowing it to perform its function as an on-switch.Furthermore, the switch itself can be made at a low cost due to the small number of components and low parts cost. It can be configured as follows.

[Brief explanation of the drawing]

FIG. 1 is an alarm circuit diagram of a fire alarm clock to which the present invention is applied, FIG. 2 is a sectional view of a temperature switch, and FIG. 3 is a sectional view showing another embodiment of the temperature switch. In the figure, 10...Alarm circuit, 11...Battery, 12
...Electric bell, 14...Temperature switch, 16,1
6A, 16B... Fixed contact, 17... Movable contact,
21... Foaming agent.

Claims (1)

[Scope of Claim for Utility Model Registration] A fire alarm clock consisting of a temperature switch connected in series to an electric alarm that turns on when the temperature at the time of fire is detected, wherein the temperature switch is made of a foaming agent with a large coefficient of thermal expansion. A fire alarm watch comprising: a movable contact provided at the movable end of the foaming agent; and a fixed contact facing the movable contact and placed at a distance.