JP2515205Y2 - Photoelectric smoke detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a photoelectric smoke detector for detecting smoke generated during a fire.

2. Description of the Related Art A conventional photoelectric smoke detector has a base 128 as shown in FIG.
It is equipped with a main body composed of a cover 130 and a cover 130.
The number 0 is fixed by the engagement between the inner peripheral undercut portion 129 of the base 128 and the hook 131 of the cover 130.

However, if the engaging force between the undercut portion 129 and the hook 131 is weak, “rattle” occurs, and a positional deviation occurs between the optical chamber 133 and the smoke inlet 134. If so, the interval of the smoke inflow space 135 will not be as designed, and the sensitivity of the sensor will be reduced.

Therefore, in order to solve this problem, the shield case 132
Thus, the inner surface of the cover 130 is pressed outward to increase the engaging force.

In FIG. 9, 140 is an optical stand inserted in the printed board 141, 142 is a light emitting element, and 143 is an insect-proof wire mesh surrounding the optical chamber 133.

Problems to be Solved by the Invention In the conventional optical smoke detector, since the shield case 132 is made of a material that is harder than the base 128 and the cover 130, the main body side is burdened.

Further, in the photoelectric smoke detector that does not use the shield case, it is impossible to increase the engaging force by the above method.

Based on the above circumstances, the present invention aims to prevent the base and the cover from rattling without a shield case.

Means for Solving the Problems The present invention relates to a protrusion provided on an inner surface of a base; a printed circuit board mounted on the protrusion; and an optical chamber mounted on an optical table mounting portion of the printed circuit board. The photoelectric smoke detector includes: a cover that covers the optical chamber and covers the base; and an engagement unit that presses the optical chamber onto the printed circuit board and the cover. To do.

The printed circuit board is placed on the protruding portion of the base, the optical chamber is placed on the optical base mounting portion of the printed circuit board, and the optical chamber is covered with a cover to cover the base.

Then, the printed circuit board and the cover are pressure-bonded to the optical chamber by the engaging means. At that time, the printed circuit board, the optical base, and the cover bend to function as springs, so that the engaging force of the engaging portion is strengthened.

Embodiment An embodiment of the present invention will be described with reference to the accompanying drawings.
The same reference numerals have the same names and functions.

A blade metal fitting mounting portion 30 is formed on the back surface 1a of the base 1 of the sensor, and a plurality of protruding portions 5 for supporting the printed circuit board 3 are formed on the inner surface 1b thereof, as shown in FIG. A plurality of hook portions 9 for fixing the optical bench 6 are formed. At the center of the protruding portion 5, a screw hole 31 communicating with the blade mounting portion 30 is formed. A claw 8 is formed at the tip of the hook portion 9, and the claw 8 is composed of two claws 8a and 8b formed inward as shown in FIG.

As shown in FIG. 7, the printed circuit board 3 has its surface 3a.
An optical bench mounting portion 37 is formed in the central portion of the, and a plurality of soldering portions 33 formed on the outer periphery of the pin hole 32 on the outside thereof,
A plurality of through holes 34 through which the hook portions 9 pass, and a pin portion 35 of the optical stand 6.
And a plurality of pin holes 36 into which are inserted are formed.

Although the printed circuit board 3 is provided with an electronic circuit and the like, the description is omitted here. Back side of optical stand 6
As shown in FIG. 5, 6a is provided with a plurality of pin portions 35 which are inserted into the pin holes 36 of the printed circuit board 3, and the outer peripheral edge 7a thereof is provided with the claws 8 of the hooking portions 9. A plurality of step portions 7 that engage with each other, and a plurality of hooks that engage with the engagement member 11 of the cover 2
10 and are provided.

The optical chamber 4 of the optical table 6 is provided with a labyrinth, a light projecting element, etc., but the description thereof will be omitted.

The cover 2 is formed to have a mountain-shaped cross section so that smoke can smoothly flow into the optical chamber 4, and an optical chamber insertion recess 38 is formed in the center thereof, and a peripheral edge of the insertion recess 38 is As shown in FIG. 3, an engaging member 11 for engaging with the hook 10 is provided. The roof 12 is provided at a position facing the insertion recess 38 through a rib (not shown), and a protrusion 12a of the roof 12 is in contact with the top 13 of the optical chamber 4. An annular groove 16 is formed on the inner surface 17a of the inclined surface 17 of the cover 2 in order to prevent contact with the edge 3b of the substrate 3. The depth of the groove 16 is appropriately selected as needed. In addition, 23 is a smoke inlet for allowing smoke to enter the optical chamber 4, 24 is a wire mesh for preventing insects from entering the optical chamber 4, and 25 is for confirming the operation of the sensor. The operation confirmation lights are shown respectively.

 Next, the operation of this embodiment will be described.

The pin portion 35 of the optical base 6 is inserted into the pin hole 36 of the printed circuit board 3, the optical base 6 is brought into contact with the optical base mounting portion 37 of the printed circuit board 3, and the lead wires of the light emitting element and the light receiving element are not shown. Solder to the printed wiring. Blade mounting part 30 of base 1
After the blade fitting 18 is brought into contact with the blade, the pin 19 is screwed into the screw hole 31 to fix the blade fitting 18 to the base 1. Insert the tip of the pin 19 into the pin hole 32 of the printed circuit board 3 to
Is abutted on the tip of the protrusion 5, and the tip of the pin is soldered 33a to the soldering portion 33 to fix the printed circuit board 3 to the protrusion 5.

At this time, the claws 8 of the hooks 9 are formed in the through holes of the printed circuit board 3.
It projects through the surface 34 of the printed circuit board 3 through 34. When the optical chamber 4 is pressed in the direction of the arrow A3, the printed circuit board 3 bends and, as shown in FIG. 2, the claw 8 of the hook 9 engages with the step 7 of the optical base 6. At this time, the optical chamber 4 is pressed in the direction opposite to the arrow A3 by the restoring force of the outer peripheral edge 7a of the optical base 6 and the printed circuit board 3, so that the engaging force between the step portion 7 and the claw 8 becomes strong. In this way, the optical table 6 is regulated in position by the pin portion 35 and the claw 8 and thus is accurately fixed in the prescribed position. While aligning the optical chamber 4 of the optical table 6 and the optical table insertion recess 38 of the cover 2, the cover 2 is put on the optical chamber 4 and pressed in the direction of the arrow A2, the cover 2 bends and the cover 2 shown in FIG. As shown in, the engaging member 11 of the cover engages with the hook 10 of the optical table.

At this time, the optical chamber 4 is moved to the arrow direction by the restoring force of the cover 2.
Since it is pressed in the direction opposite to A2, the engaging force between the engaging member 11 and the hook 10 becomes stronger.

The flexibility of the printed circuit board 3, the optical base 6 and the cover 2 eliminates the rattling of the whole, but here the printed circuit board 3 is made rigid and the optical base 6 and the cover 2 are made flexible. It is preferable to reduce the load on the printed circuit board 3 by using the above-mentioned structure.

The outer peripheral edge 3b of the printed circuit board 3 is close to the inner surface 17a of the inclined surface 17 of the cover 2, but since the outer peripheral edge 3b is located at a position facing the annular groove 16 of the cover, the printed circuit board 3 and the cover 2 are Will never come into contact.

In this way, the assembled photoelectric smoke detector is brought close to the base 21 fixed to the ceiling surface or the like, rotated, and the blade 18 of the detector is inserted into the blade holder 22 of the base 21.

The embodiment of the present invention is not limited to the above. For example, the engaging member 11 of the cover 2 shown in FIG.
Without engaging with the hooks 10, the undercut portion 26 is provided on the peripheral wall 15 of the base 1 as shown in FIG.
The hook 27 is provided at the corresponding position of the
26 and the hook 27 may be engaged with each other.

By fixing the cover 2 to the peripheral wall 15 of the base 1 in this manner, the projection 12a of the cover 2 causes the optical chamber 4 to move toward the arrow A12.
The printed circuit board 3 is bent in the same direction by pressing in the same direction.
Then, the optical base 6 is moved to an arrow by the restoring force of the printed circuit board 3.
By being pressed in the direction opposite to the A12 direction, the engaging force between the hook 27 and the undercut portion 26 is strengthened.

Effect of the Invention Since the photoelectric smoke detector according to the present invention is configured as described above, the engagement between the base and the cover that is fixed via the optical chamber by the spring action of the printed circuit board, the optical base, and the cover. Strength is strengthened.

Therefore, “rattle” does not occur in the engaging portion, and the sensitivity of the sensor is not lowered.

[Brief description of drawings]

1 to 7 are views showing an embodiment of the present invention. FIG. 1 is a longitudinal sectional view, and FIG. 2 is an enlarged view of an engaging portion between a base and an optical base in FIG. 3 is an enlarged view of the engaging portion between the optical base and the cover of FIG. 1, FIG. 4 is an enlarged perspective view of the claw of the hooking portion, FIG. 5 is a side view of the optical base, and FIG. A plan view, FIG. 7 is a plan view of a printed circuit board, FIG. 8 is a longitudinal sectional view showing another embodiment, and FIG. 9 is a longitudinal sectional view showing a conventional example. 1 …… Sensor base 2 …… Cover 3 …… Printed circuit board 4 …… Optical chamber 5 …… Projection 6 …… Optical stand 9 …… Hook 10 …… Hook

Claims (5)

(57) [Scope of utility model registration request] 1. A projecting portion provided on an inner surface of a base; a printed circuit board mounted on the projecting portion; an optical chamber mounted on an optical table mounting portion of the printed circuit board; A photoelectric smoke detector, comprising: a cover which covers and covers the base; and an engagement means which presses the optical chamber onto the printed circuit board and the cover. 2. An engaging means, a hooking portion on an inner surface of a base which is locked to the optical chamber, and an engaging member of a cover which is locked to the optical chamber.
The photoelectric smoke detector according to claim 1, wherein the photoelectric smoke detector comprises: 3. The photoelectric smoke detector according to claim 1, wherein the engaging means comprises a head portion of the cover that abuts against the light receiving chamber and an engaging member of the cover that engages with the base. 4. The engaging means comprises a hooking portion on the inner surface of the base which is locked in the optical chamber, a head of the cover which is in contact with the optical chamber, and an engaging member of the cover which is locked in the base. The photoelectric smoke detector according to claim 1, wherein: 5. The photoelectric smoke detector according to claim 3, wherein the head of the cover is in contact with the optical chamber through the protrusion.