JPH0512870Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waterproof fire detector having a waterproof structure that prevents moisture from entering the electric circuit inside the sensing housing through the lead wire lead-in portion.

Conventionally, in waterproof fire detectors, in order to prevent water and moisture from entering the electrical circuit inside the housing through the lead wire lead-in part, the electrical circuit is used as a lid for the compartment that houses the electrical circuit. It is formed by resin molding with the core wire of the lead wire connected to the lead terminal to be connected. When molding a lid member using such a resin mold, the lead terminal made of a metal material has good compatibility with the molding resin, resulting in a sufficient sealing structure. They do not fit well, and a small gap is created between the lead wire and the molded resin.

In particular, when installing a fire detector in a place with high temperatures and a lot of water vapor, such as a quenching workshop in a steel factory, the fire detector's casing should be made of a resin mold containing glass fiber to increase its heat resistance. It is necessary to use wires coated with heat-resistant resin such as tetrafluoroethylene, and in order to obtain waterproofness in addition to such a heat-resistant structure, molding the lid member integrally with the lead wires The compatibility between the wire's heat-resistant coating and the molding resin is even worse, and during use, water and moisture can enter the lead terminal connection part inside the mold through the gap between the lead wire and the molding resin, and the lead wire usually has positive and negative connections. Because a pair of lead wires were drawn in, there was a risk that moisture would adhere to the exposed core of the lead wire, resulting in a short circuit.

The present invention was developed in view of these conventional problems, and is a waterproof fire detector in which an electric circuit is housed in a compartment formed within the detector housing, and the compartment is sealed by attaching a lid member. In the case of the resin molding of the lead wire for the lid member, the covering part on the drawer side of the lead wire is covered with an elastic sealing material such as silicone rubber, and the covering part on the drawer side of the lead wire and the lead terminal are integrally molded in resin. An object of the present invention is to provide a waterproof fire detector in which a lead wire covering and a molded resin are brought into close contact with each other using an elastic sealing material to reliably prevent moisture from entering from the outside.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention, taking a heat-resistant and waterproof fire detector as an example.

First, to explain the configuration, 1 is a sensor housing molded with heat-resistant resin such as glass.
A heat sensing part 2 is attached to the lower tip, and the heat sensing part 2 is composed of a heat collecting plate 3, a bimetal 4, a contact terminal 5 that is closed by reversing the bimetal 4, and a support terminal 6. The attachment portion of the heat sensitive section 2 is waterproofed with an adhesive 7.

A compartment 9 whose periphery is partitioned by a partition wall 8 is formed in the sensor housing, and a printed circuit board 10 on which electrical components 11 are mounted is housed inside this compartment 9.
The contact terminals 5 and support terminals 6 of the heat sensitive part 2 are connected to this printed circuit board 10, and the electric circuit formed on the printed circuit board 10 generates an alarm when the contact terminals 5 are closed due to the thermal operation of the bimetal 4. Sends a signal to the receiver side and also sends an alarm indicator light 1
2 is formed.

The upper part of the compartment 9 housing the printed circuit board 10 on which the electrical components 11 are mounted is sealed via a sealing gasket 13 with a lid member 15 also made of heat-resistant resin. This lid member 15 has lead terminals 16 connected to the electric circuit of the printed circuit board 10.
and a lead wire 18 connected to the lead terminal 16 and drawn out to the outside are integrally molded with resin.

Further, a guard protector 14 is fitted to the lower part of the sensor housing 1 to protect the heat sensitive section 2.

2 is a partial cross-sectional view of the lid member 15 taken out from the embodiment shown in FIG. shows a side view.

That is, the lid member 15 used in the present invention has four mounting screw holes 19, and as is clear from the A-A cross section in FIG. terminal 16
A pair of single lead wires 18 connected to the lead terminals 16 and drawn out are embedded in a resin mold, and the lead wires 18 are covered with a heat-resistant coating such as tetrafluoroethylene. is used.

When resin molding the lead terminal 16 and the lead wire 18, the core wire 18a of the lead wire 18 is connected to the embedded end of the lead terminal 16 by caulking.
Further, the covered portion of the lead wire 18 on the draw-out side is covered with an elastic sealing material 20 such as silicone rubber and set in a mold, and is molded integrally with the lid member 15 by injection molding of heat-resistant resin. By this molding, the elastic sealing material 20 is attached to the lead wire 18.
The lead wire 18 is crimped onto the covered portion of the lead wire 18 by the molding resin, and the lead wire 18 can be sealed without creating a gap between the covering and the molding resin.

Next, the operation will be described.

First, when assembling the sensor, the printed circuit board 10 is attached and soldered to the tip of the lead terminal 16 formed integrally with the lid member 15, and in this state, the first
As shown in the cross-sectional view in the figure, the printed circuit board 10 is inserted into the contact terminals 5 and the support terminals 6 from the heating section 2 through the seal packing 13, and the lid member 15 is attached to the sensor housing 1 side. By fixing with screws, the compartment 9 housing the printed circuit board 10 on which the electrical component 11 is mounted is hermetically sealed.

The compartment 9 sealed by the lid member 15 in this way
Seal packing 13 to prevent water and humidity from entering
This is prevented by the lid member 15 of the compartment 8 interposed therebetween, and the lead wire 18 is integrally resin-molded inside the lid member 15 with an elastic sealing material 20 interposed therebetween. Moisture transmitted through the gap between the mold resin and the lid member 15
The lead wire 18 is cut by the elastic sealing material 20 and does not enter the connection part with the lead terminal 16, and moisture passing through the coating of the lead wire 18 is absorbed by the core wire 18a of the lead wire 18 inside the lid member 15. It penetrates to the connection part with lead terminal 16, but lead terminal 1
6 is resin molded on the lid member 15, so
The resin molded portion of the lead terminal 16 and the elastic sealing material 20 block moisture from entering, thereby reliably preventing moisture from entering the compartment 9.

In particular, the lead wire 1 molded in resin on the lid member 15
8 is a disconnection sealing material 2 as shown in FIGS. 2 and 3.
0, the connection part of the lead wire 18 inside the lid member 15 is completely sealed with the elastic sealing material 20 and there is no gap.
8 and prevents short circuit between a pair of lead wires 18 due to adhesion of moisture.

As explained above, according to the present invention, an electric circuit is housed in a compartment formed inside a sensor housing,
In a waterproof fire detector in which the compartment is sealed by attaching a lid member, the resin mold of the lead wire to the lid member is covered with an elastic sealing material such as silicone rubber on the lead-out side of the lead wire. Since the drawer side covering part and the lead terminal are integrally molded with resin, even if a gap is created due to insufficient compatibility between the lead wire covering and the molding resin, the elastic sealing material seals the gap and prevents water and moisture from entering the interior. It is possible to easily and easily realize a waterproof structure that reliably prevents lead wire short circuits and can withstand use in high temperature and high humidity environments.

In addition, although the above embodiment took the waterproof structure of a heat-resistant fire detector as an example, the present invention is not limited to this, and can be applied as is to fire detectors used in high humidity environments at room temperature. can do.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 is an explanatory view showing a partial cross section of the lid member in the embodiment of Fig. 1, and Fig. 3 is A of Fig. 2. −
A sectional view and FIG. 4 are side views of the lead wire drawer of FIG. 2. DESCRIPTION OF SYMBOLS 1... Sensor housing, 2... Heat sensitive part, 8... Partition wall, 9... Compartment, 10... Printed circuit board, 15...
... Lid member, 16 ... Lead terminal, 18 ... Lead wire, 18a ... Core wire, 20 ... Elastic sealing material.

Claims (1)

[Scope of Claim for Utility Model Registration] A waterproof fire detector in which an electrical circuit is housed in a compartment formed in a detector housing, and the compartment is sealed by attaching a lid member, wherein the lid member is configured to house the electrical circuit in a compartment formed in the detector housing. A waterproofing device characterized in that the lead-out side sheathing portion of the lead wire whose one end is connected to the lead terminal connected to the lead wire is covered with an elastic sealing material, and the lead-out side sheathing portion of the lead wire and the lead terminal are integrally molded with a resin mold. type fire detector.