JP2537575Y2 - Thermal fire detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION This invention relates to a fire detector. More specifically, the present invention relates to a fire detector. The present invention relates to a thermal fire detector that can be easily disassembled.

2. Description of the Related Art In a fire detector that uses a semiconductor thermal element such as a thermistor, a lead wire of the thermal element is inserted into an insertion hole provided in the sensor body to mount the thermal element, and the end of the lead wire is connected to the thermal element body. Solder is inserted through the connection hole of the printed circuit board provided on the back side.

Problems to be Solved by the Invention In the conventional example, the soldering of the lead wires must be performed in a narrow place on the back side of the body, and there is a problem that the work is troublesome and difficult to assemble.

In order to obtain a waterproof structure or a corrosion-resistant structure, the lead wire insertion hole of the body must be sealed with a filler. However, if the filler is filled from the back side of the body after the lead wire is inserted and before soldering (that is, before mounting the printed circuit board), an excessive force is applied to the lead wire when soldering the printed circuit board. In addition, there is a problem that the lead wire is apt to be broken, and there is a problem that the protruding distance of the heat-sensitive element is easily deviated during filling. In addition, the filling of the filler after soldering the lead wires must be performed from the back side of the body, and there is a problem that the filler is exposed on the surface of the body and the appearance is impaired.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to facilitate disassembly and assembly, and to easily waterproof a mounting portion of a fire detection element. Another object is to facilitate the adjustment of the mounting height of the fire detection element and to prevent the lead wires of the element from being damaged.

Means for Solving the Problems The present invention provides a thermal sensor in which a lead wire of a thermosensitive element provided outside a housing is connected to a printed circuit board in the housing. An element mounting base detachably engageable, a back wall of the element mounting base surrounds a through hole through which a lead wire of a thermosensitive element is inserted, and an enclosing wall for mounting the engaged printed circuit board is provided. The object is achieved by providing an injection hole communicating with a space surrounded by the element mounting base, the surrounding wall, and the printed board on the substrate.

After passing the tip of the lead wire of the heat-sensitive element through the through hole of the element mount, the element mount is engaged with the printed board while the tip is passed through the connection hole of the printed board, and the printed board is mounted on the end face of the surrounding wall. Place. Next, the lead wire is soldered to the printed circuit board while adjusting the position of the thermal element.

When the filler is injected into the injection hole of the printed circuit board, the space is filled with the filler and sealed.

An embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same reference numerals have the same names and functions. The resin housing F of the waterproof fire detector is composed of a main body 1 for housing a printed circuit board 11 and an element mounting base 4 for supporting a flame detecting unit such as a thermal element.
And a protective cover 2.

A projection 1A, a locking projection 1B, and a cylindrical wall 102 protrude from a bottom surface 1a of the bottomed cylindrical main body 1, and an outer seal portion 101 is provided at a tip of the cylindrical wall 102. As shown in FIG. 2, a through hole 44 that penetrates a semiconductor thermosensitive element, for example, a lead wire 141 of the thermistor 14, is formed at a substantially central portion of the element mounting base 4, and the through hole 44 is formed on the back side thereof. Is provided with an enclosing wall 43 and a locking column 42. An inner seal portion 41 is provided on the periphery of the element mount 4. The protective cover 2 covers an annular portion between the main body 1 and the element mounting base 4, and has an inner surface provided with an outer seal portion 22 having a side wall 22a.

The seal portion 22 is provided with a fixing post 23 having a hook-like tip.

Inside the outer seal portion 22, an inner seal portion 21 is provided.

3 and 4, the printed circuit board 11 has a locking hole 111 for locking the locking column 42 of the element mounting base 4.
An injection hole 112 for injecting the filler and a connection hole 113 for inserting the lead wire 141 of the thermistor 14 are formed, and the diameter L of the substrate 11 is formed larger than the diameter D of the element mount 4. Also, the main body 1 is engaged with the large diameter portion 11a outside the element mounting base 4. Next, how to assemble the fire detector will be described. For printed circuit board 11 for constant temperature type, differential type,
Solder circuit components (not shown) for the analog type, the DIP switch 15, and the like. Thermistor 14 lead wire
141 is inserted through the through hole 44 of the element mounting base 4, the tip of which is inserted into the hole 113 of the printed circuit board 11, and the locking column 42 of the mounting table 4 is inserted and locked into the locking hole 111 of the printed circuit board 11. . At this time, the lower surface of the printed circuit board 11 contacts the upper edge of the surrounding wall 43. Thereafter, the lead wire 141 is soldered and fixed to the printed circuit board 11 while the thermistor 14 is positioned at the set height, and the excess portion is cut.

In this state, the filler 19 such as silicon is injected through the injection hole 112 of the printed circuit board 11.

As a result, the filler 19 flows into a space surrounded by the mounting table 4, the surrounding wall 43, and the printed circuit board 11, and a part thereof also flows into a gap between the through-holes 44, and seals with the outside through the through-holes 44. The lead wire 141 of the thermistor 14 is fixed.

Since the lead wire 141 is fixed in this manner, the height of the thermistor 14 with respect to the element mount 4 is easily adjusted, and the lead wire 141 is forcibly pulled when the lead wire 141 is soldered to the printed circuit board 11. There is no damage such as disconnection.

In addition, since the filler 19 flows into the through-hole 44 into which the lead wire 141 is loosely inserted, the through-hole 44 is reliably sealed.

At this time, since the filler 19 is injected from the back side of the element mounting base 4, the filler 19 does not flow out to the surface side of the element mounting base 4, so that the beauty is not spoiled. Next, the lead wire 12 for external line connection is passed through the hole of the concave portion 105 of the main body 1,
The tip is inserted into the connection hole 114 of the printed circuit board 11 and fixed by soldering, and the lead wire 12 is pulled outward. Then, the printed board 11 is engaged with the larger diameter portion 11a of the mounting base 4 by inserting a locking projection (not shown) of the main body 1 into a hole 117 provided on the outer side of the locking hole 111. Then, the main body 1 is brought into contact with the lower surface such as the concave portion 105 or the convex portion 1A projecting below the bottom surface 1a. In addition, a projection for positioning is provided on the contact surface of the projecting portion such as the concave portion 105, and this projection is attached to the printed circuit board.
You may make it penetrate through the positioning hole provided in 11. Alternatively, the lead wire 12 may be soldered to the printed board 11 in advance, and the lead wire 12 may be passed through the hole of the recess 105 when the printed board 1I is attached to the main body 1.

Then, the inner O-ring 9 is press-fitted and mounted on the side wall 41a of the inner seal portion 41 of the element mounting base 4, and the outer O-ring 10 is press-fitted and mounted on the side wall 101a of the outer seal portion 101 of the main body 1. The fixing column 23 of the protective cover 2 to which the engagement 3 is fixed is inserted into the gutter-shaped portion 103 of the main body 1 and the hook at the tip thereof is hooked and engaged with the upper edge of the gutter-shaped portion 103. At this time,
There is a so-called play between the side wall 21a of the inner seal portion 21 of the protective cover 2 and the side wall 41a of the inner seal portion 41 of the element mounting base 4, so that the side walls 21a, 41a relatively move and displace in the horizontal direction. , And presses the inside and outside of the O-ring 9. Therefore, a centripetal action is generated on the O-ring 9, so that the O-ring 9 is naturally tightened uniformly in all directions.

Therefore, since no partial force is applied to the resin housing F, the O-ring 9 is fixed in a stable state. The outer O-ring 10 is fixed in the same manner as the inner O-ring 9.

In this manner, the fire detector is sealed by the O-rings 9 and 10, the recess 105, and the filler 19 surrounded by the surrounding wall 43.
Does not penetrate into the storage section.

Also, as described above, when the printed circuit board 11, the element mounting base 4, the protective cover 2, and the protector 3 are incorporated into the main body 1, they are assembled by engagement except for the soldering of the thermistor 14 and the lead wire 12, so that fine screws and the like are used. Parts can be largely omitted, and it is easy to manufacture and can be assembled in a short time.
In addition, the disassembly only needs to be released from the engagement, so that the disassembly is easy and the maintenance and inspection and repair are simplified. In FIG. 1, reference numeral 16 denotes a sensor base fixed to a ceiling plate or the like, and reference numerals 17 and 18 denote blade holders into which the blade bracket 8 is inserted by rotation.

Effect of the Invention Because the thermal fire detector according to the invention is configured as described above, both sides of the printed circuit board can be used as electric component mounting portions, and connection with electric components on the main body side is performed at an outer peripheral portion. Can be. Therefore, the printed circuit board can be attached to the main body after incorporating various parts including the fire detection element, and the printed circuit board can be easily detached from the main body with the element support stand attached during maintenance and repair. it can.

In addition, since the filler can be filled after the fire detecting element is soldered to the printed circuit board via the element support, there is no fear that the filler damages the lead wire, and the mounting height of the fire detecting element can be reduced. Adjustment becomes easy.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIGS.
FIG. 2 is a component diagram, FIG. 2 is a sectional view of an element mounting table, FIG. 3 is a longitudinal sectional view of a printed board, and FIG. 4 is a plan view of the printed board. DESCRIPTION OF SYMBOLS 1 ... Main body 1A ... Convex part 1B ... Locking protrusion 2 ... Protective cover 4 ... Element mounting base 11 ... Printed circuit board 14 ... Thermal element 19 ... Filler 43 ... Enclosure wall 112 ... Injection hole 141: Through-hole F: Housing

Claims (3)

(57) [Scope of request for utility model registration] 1. A thermal sensor in which a lead wire of a thermosensitive element provided outside a housing is connected to a printed circuit board in the housing.
A part of the housing is an element mounting base on which the printed circuit board is detachably engaged from the rear side, and the rear surface of the element mounting base surrounds a through hole through which a lead wire of the thermosensitive element is inserted, and is engaged. A thermal fire detector comprising: a surrounding wall on which a printed circuit board is mounted; and an injection hole communicating with a space surrounded by the element mounting base, the surrounding wall, and the printed circuit board. 2. The housing comprises a main body, an element mounting base, and a protective cover. The element mounting base is locked to the main body via a printed circuit board, and the protective cover is directly locked to the main body. The thermal fire detector according to claim 1, wherein: 3. The thermal fire according to claim 1, wherein the element mounting base has a smaller diameter than the diameter of the printed circuit board, and the printed circuit board is attached to the main body at a portion larger in diameter than the element mounting base. sensor.