JP2515220Y2 - Thermal fire detector - Google Patents

Description

[Detailed Description of the Invention] Industrial field of application The present invention relates to a fire detector. More specifically, the waterproofness and airtightness are stable over a long period of time, and the structure is simple and easy to assemble. The present invention relates to a thermal fire detector that can be easily disassembled.

2. Description of the Related Art Conventionally, as a waterproof structure for circuit parts such as a printed circuit board of a fire detector, the first method of filling the back side of the printed circuit board with a filling material such as a synthetic resin (Jitsuko Sho 58-3187).
No.), a second method in which a packing such as an O-ring is placed in the circuit component accommodating portion of the sensor main body, and the back cover is screwed to the main body and the packing is pressure-welded to the main body (Japanese Utility Model Publication No. 54-15527). It has been known.

Problems to be Solved by the Invention The conventional fire detector has the following problems. That is, in the first method, even if the sensor once filled becomes defective later, it cannot be repaired. Also, as the size of the printed circuit board increases, the amount of the filler also increases, so that the sensor becomes heavier. In addition, the second method is troublesome because the screw must be attached and detached when repairing due to a failure.
Further, when the screw is tightened at three or four places, the lid made of resin is curved, and it is difficult for the pressing force to be evenly applied to the O-ring. Therefore, the pressure contact state with respect to the O-ring may be partially weakened to cause seal leakage.

In view of the above circumstances, the present invention aims at obtaining a fire detector which is easy to disassemble and assemble, and which has a stable sealing property over a long period of time.

Means for Solving the Problems The present invention is provided with a locking projection and a convex portion that project downward from the bottom surface of a bottomed cylindrical main body, and engages with the locking projection and abuts the convex portion to print inside the main body. An element mounting base, in which a substrate is engaged and arranged, a through hole is provided in a substantially central portion, and a surrounding wall that surrounds the through hole is provided on a back surface side, is provided with a locking strut provided so as to project to the surrounding wall and the back surface side. Is mounted on the printed circuit board by means of soldering, the lead wire of the heat sensitive element is inserted into the through hole of the element mounting base and inserted into the connection hole of the printed circuit board and soldered, and the lead wire for external line connection is soldered to the printed circuit board. Connected and penetrating the bottom surface of the main body, an annular protective cover that covers this annular portion is locked to the main body by a fixing strut in the annular portion between the main body and the mounting element base. Side wall of inner seal part corresponds to this side wall Then, the side wall of the inner seal portion is provided on the inner edge side of the protective cover to hold the inner O-ring in pressure contact, and the side wall of the outer seal portion near the peripheral edge in the body corresponds to the outer edge side of the protective cover. Side walls of the outer seal portion are provided respectively to hold the outer O-ring under pressure, and a sealing filler is provided in a recess through which a lead wire for connecting an outer wire of the main body penetrates. It is intended to achieve the above-mentioned object by providing a sealing filler in the formed space portion.

Action Solder a DIP switch etc. to the printed board,
The lead wire of the semiconductor thermosensitive element is inserted through the through hole of the element mounting base, the tip of the lead wire is inserted into the hole of the printed circuit board, and the locking column of the mounting base is inserted and locked into the locking hole of the printed circuit board.

The lower surface of the printed circuit board is brought into contact with the convex portion and the upper edge of the surrounding wall, then the lead wire is soldered to the printed circuit board to connect and fix it, and the filling material is injected from the injection hole of the printed circuit board, the mounting base, the surrounding wall and the print The filling material is caused to flow into the space surrounded by the substrate and a part thereof is caused to flow into the gap between the through holes to seal the outside with the through holes and fix the lead wire of the heat sensitive element.

Next, the lead wire for external wire connection is passed through the hole of the recess of the main body, the tip is inserted into the connection hole of the printed circuit board and fixed by soldering, and the lead wire is pulled outward, and the printed circuit board is locked with projections and recesses. Abut the bottom surface of

Then, the inner O-ring is press-fitted and mounted on the side wall of the inner seal part of the element mounting base, and the outer O-ring is press-fitted and mounted on the side wall of the outer seal part of the main body, and the fixing column of the protective cover is fixed to the gutter-shaped part of the main body. And the hook portion at the tip thereof is hooked and engaged with the upper edge of the gutter-shaped portion.

Embodiment 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 the same functions.

The resin-based housing F of the waterproof fire detector is a printed circuit board 11
And a protective cover 2 for supporting a fire detecting unit such as a thermosensitive element.

As shown in FIG. 2, a convex portion 1A, a locking projection 1B, and a cylindrical wall 102 are provided on the bottom surface 1a of the bottomed cylindrical main body 1 so as to project therefrom.
A step-shaped outer seal portion 101 having a side wall 101a at the tip of 02
Is provided.

This seal portion 101 is formed in an annular shape, and its outer diameter A is slightly larger than or equal to the inner diameter a of the outer O-ring 10 shown in FIG. As shown in FIG. 5, a semiconductor type heat-sensitive element, for example,
A through hole 44 penetrating the lead wire 141 of the thermistor 14 is formed, and a surrounding wall 43 surrounding the through hole 44 and a locking strut 42 are provided on the back surface side thereof. A step-like inner seal portion 41 having a side wall 41a is provided on the peripheral portion of the element mounting base 4. The outer diameter D of the seal portion 41 is slightly larger than or the same as the inner diameter d of the inner O-ring 9 shown in FIG. The protective cover 2 covers the annular portion between the main body 1 and the element mounting base 4, and as shown in FIG.
An outer seal portion 22 having a side wall 22a is provided. The seal portion 22 is formed in an annular shape, and its inner diameter B is slightly smaller than or equal to the outer diameter b of the outer O-ring 10. The seal portion 22 is provided with a fixing column 23 having a hooked end.

The inner seal portion 21 having the side wall 21a is arranged inside the outer seal portion 22, and the inner diameter E of the seal portion 21 is slightly smaller than the outer diameter e of the inner O-ring 9, or
It has the same diameter.

As shown in FIG. 7, the printed circuit board 11 has locking holes 111 for locking the locking posts 42 of the element mounting base 4, injection holes 112 for injecting a filler, and lead wires of the thermistor 14. A connection hole 113 through which 141 can be inserted is formed,
The substrate 11 engages with the main body 1 at a portion having a diameter larger than that of the element mounting base 4. Next, how to assemble the fire detector will be described. Circuit parts (not shown) for constant temperature type, differential type, analog type, etc., DIP switch 15, etc. are soldered to the printed board 11. The lead wire 141 of the thermistor 14 is inserted into the through hole 44 of the element mounting base 4 and the tip thereof is inserted into the hole 113 of the printed board 11, and the locking column 42 of the mounting base 4 is locked to the locking hole 111 of the printed circuit board 11. Insert through and lock. At this time, the lower surface of the printed circuit board 11 contacts the upper edge of the surrounding wall 43. After that, the lead wire 141 is soldered to the printed circuit board 11 to be fixedly connected,
Cut off the excess part. 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 filling material 19 flows into the space surrounded by the mounting base 4, the surrounding wall 43 and the printed circuit board 11 and a part of the filling material 19 also flows into the gap of the through hole 44 to seal the outside of the through hole 44 and prevent the thermistor. Fix the 14 lead wires 141. Since the lead wire 141 is fixed in this manner, the height of the thermistor 14 with respect to the element mounting base 4 can be easily adjusted and the lead wire 141 can be easily adjusted.
When the 141 is soldered to the printed circuit board 11, the lead wire 141 is not forcibly pulled, and 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 filling material 19 is injected from the back side of the element mounting base 4, the filling material 19 does not flow out to the surface side of the element mounting base 4, so that the aesthetic appearance is not impaired. 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 of the printed circuit board 11 and fixed by soldering, and the lead wire 12 is pulled outward. The printed circuit board 11 has a larger diameter than the mounting base 4, that is, a locking hole.
The bottom 1 of the main body 1 is inserted into a hole (not shown)
A locking projection 106 having a flange portion is inserted through the tip provided to project downward from a and is engaged with the bottom surface 1a of the main body 1 and the lower surface such as a concave portion 105 or a convex portion 1A projecting downward. Contact.

Note that a positioning protrusion may be provided on the contact surface of the protruding portion such as the concave portion 105, and the protrusion may be inserted into a positioning hole provided on the printed circuit board 11. Further, the lead wire 12 is soldered to the printed circuit board 11 in advance, and the printed circuit board 11 is
The lead wire 12 may be passed through the hole of the concave portion 105 when the 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,
Since there is 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, the side walls 21a and 41a move relatively in the horizontal direction A and are displaced. Meanwhile, as shown in FIG. 7, the inner portion 9a and the outer portion 9b of the O-ring 9 are pressed. 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 also 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.
Will not enter the storage compartment of the.

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 Since the fire detector according to the present invention is configured as described above, when the O-ring is clamped while sliding the side wall in the horizontal direction, the O-ring exerts a centripetal effect, and the O-ring moves from the horizontal direction. It is tightened with equal force over the entire circumference.

Therefore, since the O-ring is fixed in a stable state for a long period of time, the sealing property and waterproof property are improved as compared with the conventional example.

Further, by engaging and disengaging the support pillar for locking the printed circuit board and the element mounting base and the main body for fixing the protective cover, the assembly and disassembly can be easily performed. Therefore, as compared with the conventional example, small parts such as screws can be largely omitted, and the assembling and disassembling time can be greatly shortened. Furthermore, if an injection hole is provided in the printed circuit board and the filler is injected after soldering the lead wires, the mounting height of the heat-sensitive element can be easily adjusted and unreasonable force is applied to the lead wires during soldering. Since there is no lead wire, it is possible to prevent damage caused by the work of attaching the lead wire.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIGS.
The figure is a component drawing, FIG. 2 is a vertical sectional view showing the main body, FIG. 3 is a vertical sectional view of the outer O-ring, FIG. 4 is a vertical sectional view of the protective cover, and FIG. 5 is a vertical sectional view of the element mounting base. 6 and 6 are a longitudinal sectional view of the inner O-ring, FIG. 7 is a longitudinal sectional view of the printed circuit board, and FIG. 8 is an enlarged view of an essential part of FIG. 1 …… Main body 1A …… Projection 1B …… Locking protrusion 2 …… Protective cover 4 …… Element mount 9 …… Inner O-ring 10 …… Outer O-ring 11 …… Printed circuit board 14 …… Thermal element 19… Filler 21 …… Inner seal 21a …… Sidewall 22 …… Outer seal 22a …… Sidewall 23 …… Fixing column 41 …… Inner seal 41a …… Sidewall 42… Locking column 43 …… Enclosure 44 ...... Through hole 101 ...... Outer seal 101a ...... Sidewall

Claims (4)

(57) [Scope of utility model registration request] 1. A locking projection and a convex portion projecting downward from a bottom surface of a bottomed cylindrical main body are provided, and a printed circuit board is engaged in the main body by engaging the locking projection and abutting the convex portion. An element mounting base that is provided and has a through hole provided at a substantially central portion and a surrounding wall that surrounds the through hole on the back surface side is attached to the printed circuit board by the surrounding wall and the locking support pillar that is provided so as to project to the back surface side. When mounted together, the heat sensitive element has its lead wire inserted through the through hole of the element mounting base and inserted into the connection hole of the printed circuit board and soldered, and the lead wire for external line connection is soldered to the printed circuit board and the main body An annular protective cover, which is provided through the bottom surface of the device and covers the annular part between the main body and the mounting element base, is locked to the main body by a fixing strut, and an inner seal is attached to the periphery of the element mounting base. The side wall of the part corresponds to the inner side of the protective cover. The side walls of the inner seal portion are provided to hold the inner O-rings in pressure contact with each other, the side wall of the outer seal portion is provided near the peripheral edge of the main body, and the side wall of the outer seal portion is provided on the outer edge side of the protective cover corresponding to the side wall. An outer O-ring is provided under pressure and held, a seal filler is provided in a concave portion through which a lead wire for connecting an external wire of the main body penetrates, and a seal is provided in a space formed by the element mounting base, the surrounding wall and the printed circuit board. Thermal fire detector characterized by being provided with filler 2. A thermal fire according to claim 1, wherein an opening for injecting a filler is provided at a portion of the printed board corresponding to a portion surrounded by an enclosure provided on the element mounting base. sensor 3. The thermal fire detector according to claim 1 or 2, wherein the protective cover is provided with a protector on its surface. 4. The printed circuit board is engaged with the main body at a portion having a diameter larger than that of the element mounting base, and is connected with an external wire connecting lead wire.
Thermal fire detector described