JP3225300B2 - Photoelectric smoke detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric smoke detector.

[0002]

2. Description of the Related Art In a conventional photoelectric smoke detector, a housing is formed by fitting a body and a cover, a printed circuit board is disposed on the bottom of the body, and an opening is formed on an upper surface of the housing. The optical chamber base is arranged in the opening, and the light projecting element and the light receiving element are arranged on the optical base so that the optical axis is substantially parallel to the optical chamber base. The optical chamber base is covered so as to cover the optical chamber base through the upper surface opening of the body, and the outer periphery of the labyrinth-equipped upper plate is covered with an insect net. (See JP-B-63-34520)

[0003]

In the conventional photoelectric smoke detector, since many screws are used as fixing means, assembly and disassembly are extremely troublesome and time-consuming. Further, the optical chamber base in the opening of the housing is separated from the printed board via the L-shaped bent leg to protect the electric circuit components on the printed board, so that the L-shaped bent leg is provided. The height of the housing is increased by the length of In order to reduce the thickness of the sensor, it is conceivable to reduce the height of the dark room. However, this is not preferable because the performance of the sensor is reduced. Therefore, since the height of the dark box is unavoidably set to the normal height, the sensor itself becomes thick.

[0004] In view of the above circumstances, it is an object of the present invention to facilitate assembly and disassembly and to make the height of a dark room sufficient even if the sensor itself is thinned.

[0005]

SUMMARY OF THE INVENTION The present invention is directed to an optical table.
An optical bench cover for forming a dark box over the surface;
Annular labyrinth provided and multiple on the side of optical bench
Hook formed; and a plurality of insertion holes through which the hook is inserted
Optical bench mounted with the bottom of the optical bench in direct contact with the top
Mounting part is formed, and surface mount type electric circuit parts on the lower surface
Printed circuit board provided with; a through hole of the printed circuit board
A pre-engagement portion provided on the lower surface side of the
And a locking portion for a printed circuit board .

[0006]

The light receiving table provided with the light emitting element, the light receiving element and the labyrinth is directly mounted on the printed circuit board, and the two are locked and fixed. An insect screen is provided on the outer periphery of the labyrinth, an optical bench cover is placed on the upper surface of the optical bench, and a conductive fitting such as a blade fitting is mounted on the lower surface of the main body, and the printed circuit board is fastened on the upper surface thereof with screws. Thereafter, the protective cover is engaged with the main body and fixed while covering the optical bench cover.

[0007]

An embodiment of the present invention will be described with reference to the accompanying drawings. The main body 1 is configured as shown in FIG. On the upper surface 1a of the main body 1, a support column 3 having an insertion hole 2 and a projection 9 for positioning a printed circuit board 10 are protruded.
An engaging portion 4 is provided on an outer peripheral portion of the main body 1. An annular groove 1R for drainage as shown in FIG. 2 is formed on the lower surface 1b of the main body 1, and the annular groove 1R communicates with a drainage hole 1H formed on the outer peripheral edge of the main body 1. . A blade fitting 5 as a conductive connection fitting shown in FIG. 12 is fixed to the lower surface 1b of the main body 1. The blade fitting 5 includes a fixing portion 5a
And a blade portion 5b. The fixing portion 5a is provided with a screw hole 7 to be screwed with the terminal screw 6 shown in FIG. Further, the blade portion 5 is engaged with and connected to a blade receiving fitting as a conductive connecting fitting of a base (not shown).

The printed circuit board 10 is configured as shown in FIG. On the upper surface 10a of the printed circuit board 10,
Cross-shaped shield part 11 and check terminal 12 having a large area
And an optical table mounting part 13 and an indicator lamp 14 formed on the shield part 11. A lower surface 10b of the printed circuit board 10 is provided with a surface mount type electric circuit component 10e. Also, the optical board 4 is provided on the printed circuit board 10.
0 is provided with a through hole 17 through which the hook 48 passes.
On the periphery of the insertion hole 17 on the b side, the locking portion 1 of the hook 48 is provided.
7a is provided.

The optical table holder 20 is configured as shown in FIGS. The optical bench holder 20 is formed in an L shape, and a light emitting element housing part 22, a lens housing part 23, and a light emitting window part 24 are sequentially formed at one end thereof toward the center of the holder 20, The other end is provided with the holder 2
A light-receiving element housing 25, a shield case housing 28, and a lower light-shielding wall 29 having a light-receiving window are sequentially formed toward the center of 0. Vertical insertion holes 22a and 25a continuous with the storage portions 22 and 25 are formed below the light emitting element storage portion 22 and the light receiving element storage portion 25, respectively. The bottom surface 20a of the holder 20 is horizontal, and the upper surfaces of the storage portions 22, 25 are open so that the light emitting element 30 and the light receiving element 35 can be inserted from above.

As shown in FIGS. 8 and 15, a light emitting element, for example, an LED 30, is a so-called side light emitting type light emitting element in which the optical axis is formed in a direction perpendicular to the axis. Are provided. Using this light emitting element makes it unnecessary to bend the lead terminals,
Installation work is simplified. Support portions 33 and 34 are provided on the upper and lower portions of the lens 32, respectively. The light receiving element, for example, the PD 35 has an optical axis perpendicular to the axis, and a vertical lead terminal 36 is provided below the optical axis. The shield case 37 is unpainted, and a light receiving window 38 is formed on the front surface thereof. The upper surfaces of the light emitting element 30, the lens support portion 33, and the shield case 37 are respectively provided on the upper surfaces of the contact portions 30a, 33 which are pressed against the optical bench 40.
a and 37a are formed.

The optical table 40 is shown in FIGS. 7, 14, 17, and 1.
8 is configured. Bottom surface 40 of optical bench 40
In a, a light-emitting unit housing 41, a light-receiving unit housing 42, and a light-shielding column 43, whose lower surfaces are open, are provided. The two storage portions 41 and 42 are formed corresponding to the optical bench holder 20, and the inner surface of the light-emitting portion storage portion 41 has a contact portion 41 a for pressing the light-emitting element 30 and a lens 32.
Is provided with a groove portion 45 that is in pressure contact with. Light receiving section storage section 4
2 has an upper light-shielding wall 4 in contact with a lower light-shielding wall 29.
4 and a contact portion 42a that is in pressure contact with the shield case 37. A labyrinth 47 is annularly arranged on the bottom surface 40a of the optical bench so as to sandwich the light emitting unit housing 41 and the light receiving unit housing 42 therebetween. An insect screen 46 shown in FIG. 6 is provided on the outer periphery of the labyrinth 47,
The insect net 46 is supported by an annular wall 49. The annular wall 49 is provided on the side of the optical bench 40, and its tip 49 a is located below the labyrinth 47. On the side of the optical table 40, 3
A book hook 48 is provided.

The optical bench cover 50 is configured as shown in FIGS. Cylindrical portions 51 and 52 are provided on the center and outer peripheral side of the upper surface of the optical bench cover 50, and a plurality of protrusions 54 are formed on the lower surface thereof. The projecting portion 54 is provided with a fitting hole 47 formed on the upper surface of each of the labyrinth 47, the light emitting portion housing portion 41, and the light receiving portion housing portion 42.
b, 41b, and 42b.

The protective cover 60 is configured as shown in FIGS. 1, 3 and 4. The protective cover 60 is connected to a top plate 63 via a flange 61 and a connecting column 62. The flange 61 is provided with a check rod insertion hole 64 and an indicator light hole 66, and a smoke inlet 6 is provided between the flange 61 and the top plate 63.
5 are provided. A hook that is engaged with the engaging portion 4 of the main body 1 is provided on an outer peripheral edge of the flange portion 61.

Next, the operation of this embodiment will be described. After the lead terminal 31 is inserted into the insertion hole 22a of the optical bench holder 20 and the side light emitting type light emitting element 30 is stored in the light emitting element storage part 22, the support part 34 of the lens 32 is replaced with the lens storage part 2.
Store in 3. At this time, the light emitting element 30 and the lead terminal 36
Is held vertically. Lead terminal 3 in insertion hole 25a
6, the light receiving element 35 is housed in the light receiving element housing part 25. At this time, the light receiving element 35 and the lead terminal 31 are held vertically. Further, a shield case 37 is fitted into the shield case storage section 28, and is covered with the light receiving element 35 to shield.

The optical table holder 20 is placed on the bottom surface 40 of the optical table 40.
The light emitting element 30 is housed in the light emitting part housing part 41 and the light receiving element 35 is housed in the light receiving part housing part 42.

The hook 48 of the optical table 40 is inserted into the insertion hole 17 of the printed circuit board 10, and the hook 48 is
7a. Then, while the optical table 40 is centered by the three hooks 48, its bottom surface 40a
Are directly in contact with the printed circuit board 10. In this state, the optical bench 40 is accurately positioned on the optical bench mounting portion 13, and the optical bench holder 20 is sandwiched between the optical bench 40 and the printed circuit board 10.

At this time, the light emitting element 30 of the optical bench holder 20
Abutment portion 30a, abutment portion 33 of support portion 33 of lens 32
a, the abutting portion 37a of the shield case 37 is pressed by the abutting portion 41a, the groove 45, and the abutting portion 42a on the inner surface of the optical bench, so that they are accurately arranged at predetermined positions,
Even if there is vibration, the position does not go out of order. Therefore, the optical axis L of the light emitting element 30 and the light receiving element 35 is
Can always be kept parallel to the bottom surface 40a. The optical axis L is located at substantially the same height as the tip 49a of the annular wall 49.

An insect net 46 is provided on the outer periphery of the labyrinth 47, and the insect net 46 is supported by an annular wall 49. After that, the projection 54 of the optical bench cover 50 is fitted into the fitting hole 47b of the labyrinth 47, the fitting hole 41b of the light emitting unit housing 41, and the light receiving unit housing 42b. Thereby, the inside of the optical bench 40 becomes dark, and a so-called dark box is formed. At this time, the shield case 37 is not exposed to the smoke monitoring space S because the shield case 37 is surrounded by the light receiving section housing portion 42 of the optical bench 40, the upper light shielding wall 44, and the lower light shielding wall 29 of the optical bench holder 20. Therefore, even if the shield case 37 is unpainted, the scattered light in the dark box is not reflected by the shield case. In this embodiment, the height between the inner upper surface and the inner lower surface of the dark box can be sufficiently secured, and the height from the lower surface of the main body to the upper surface of the dark box can be reduced.

The printed circuit board 10 is placed on the support column 3 of the main body 1, the tips of the projections 9 are inserted into the holes of the printed circuit board 10, and the terminal screws 6 are inserted into the insertion holes 2 and 18. Thereafter, the fixing portion 5a of the blade fitting 5 is brought into contact with the lower surface 1b of the main body 1, and the terminal screw 6 is rotated to be mounted in the screw hole 7 and fixed. The protective cover 60 is moved toward the optical bench cover 50, and the hook 67 is engaged with the locking portion 4 of the main body 1 and fixed.

The embodiment of the present invention is not limited to the above. For example, instead of directly fixing the lower surface 40a of the optical bench 40 to the printed circuit board 10, an annular ring is provided on the lower surface and the ring is attached to the printed circuit board 10. You may make it contact. Also, instead of an annular ring, a plurality, for example, 3
The projections may be arranged at intervals in the circumferential direction. The check terminals 12 may be formed in a printed pattern on the printed circuit board 10.
The zero check rod insertion hole 64 may be omitted. Further, a blade receiving member or the like may be used as the conductive connecting member.

[0021]

Since the present invention is constructed as described above, the number of screwing points is smaller than that of the conventional example, so that the sensor can be easily assembled and disassembled. Further, since the light receiving table is directly fixed to the printed board via the engaging means, unlike the conventional example, the height of the dark box can be sufficiently maintained even if the sensor is made thin. Therefore, the sensor can be made thin without deteriorating the performance.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a bottom view showing the embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view taken along line AA of FIG. 1;

FIG. 4 is a perspective view showing a protective cover of the present invention.

FIG. 5 is a perspective view showing an optical bench cover and the like of the present invention.

FIG. 6 is a perspective view showing the insect net of the present invention.

FIG. 7 is a perspective view showing an optical bench of the present invention.

FIG. 8 is a perspective view showing an optical bench holder and the like of the present invention.

FIG. 9 is a perspective view showing a terminal screw of the present invention.

FIG. 10 is a perspective view showing a printed board of the present invention.

FIG. 11 is a perspective view showing a main body of the present invention.

FIG. 12 is a perspective view showing a blade fitting of the present invention.

13 is a cross-sectional view showing the optical bench cover taken along the line AA in FIG. 1 of the present invention.

FIG. 14 is a cross-sectional view showing the optical bench taken along the line AA of FIG. 1 of the present invention.

FIG. 15 is a cross-sectional view showing a shield case, a lens, a light emitting element, and a light receiving element in a cross section taken along line AA of FIG. 1 of the present invention.

FIG. 16 is a cross-sectional view showing the optical bench holder taken along the line AA of FIG. 1 of the present invention;

FIG. 17 is a plan view of the optical bench of the present invention.

FIG. 18 is a bottom view of the optical bench of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 5 Blade fitting (conductive fitting) 10 Printed circuit board 20 Optical stand holder 30 Light emitting element 35 Light receiving element 37 Shield case 40 Optical stand 46 Insect repellent net 47 Labyrinth 50 Optical stand cover 60 Protective cover

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho 64-57594 (JP, U) Japanese Utility Model Sho 59-158049 (JP, U) Japanese Utility Model No. 2-145495 (JP, U) Japanese Utility Model No. 2- 109271 (JP, U) Practical application Microfilm (JP, U) which photographed the contents of the specification and drawings attached to the application of Japanese Patent Application No. 1-16963 (Japanese Utility Model Application No. 2-109271) (58) Int.Cl. ⁷ , DB name) G08B 17/107

Claims (3)

(57) [Claims] 1. Light forming a dark box by covering an upper surface of an optical bench.
School stand cover; an annular labyrinth provided in the dark box
And a plurality of hooks formed on the side of the optical bench;
Has a plurality of insertion holes through which the optical bench is located.
The optical table mounting part is formed to directly contact
Printed circuit board with mounting type electric circuit components
And on the periphery of the lower surface side of the insertion hole of the printed circuit board.
And an engaging portion of the printed circuit board for engaging with the hook . 2. An optical table mounting portion is fixed to a main body, and has an optical table mounting portion on an upper surface.
Formed, surface mount type electric circuit parts are provided on the lower surface
Printed circuit board; lower surface of insertion hole of the printed circuit board
A hook fixed to the locking part provided on the periphery is provided.
An optical bench whose bottom is directly abutted on the printed circuit board ;
A pair of a light emitting element and a light receiving element provided on the optical bench;
Wherein the optical bench cover forming a dark box I covering the optical bench of the upper surface; and an annular labyrinth provided in dark inner box; insect screen provided on the outer periphery of the labyrinth and, the printed circuit <br/> board, A protective cover with a smoke inlet that covers the optical bench, the insect net and the optical bench cover and engages with the main body. 3. A large area is provided on an upper surface of the printed circuit board.
Is formed, and the optical bench mounting section is
3. The photoelectric smoke detector according to claim 2, wherein the photoelectric smoke detector is formed in a shield part .