Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-10-31
2003-02-18
Wu, Daniel J. (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S628000, C340S629000, C340S693500, C250S574000
Reexamination Certificate
active
06522254
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a smoke detector equipped with an insect screen for preventing entry of insects into a smoke detecting space, as well as to an insect screen.
2. Description of the Related Art
FIGS. 19
to
22
show a commonly employed photoelectric smoke detector.
FIG. 19
is a longitudinal cross-sectional view of the smoke detector;
FIG. 20
is a transverse cross-sectional view of the smoke detector;
FIG. 21
is a layout and construction drawing of a smoke detecting section; and
FIG. 22
is a disassembly view of the smoke detector.
As shown in
FIGS. 19 and 20
, a terminal board
203
is housed in an exterior cover
201
, and a shield case
204
is fixedly attached to the interior of the terminal board
203
. A smoke detecting section main body
205
is fitted to the terminal board
203
, and a printed board
208
is provided on the smoke detecting section main body
205
. A plurality of smoke inlets
202
are formed along the circumference of the exterior cover
201
.
A smoke detecting section cover
211
is removably attached to the lower surface of the smoke detecting section main body
205
. Smoke inlets
215
are formed in the circumferential wall of the smoke detecting section cover
211
. A plurality of labyrinthine members
213
are formed inside the circumferential wall. An insect screen
214
is integrally provided on the smoke detecting section
211
.
A light-emission element
221
, such as an infrared LED or the like, is housed in a light-emission holder
217
provided on the lower surface of the smoke detecting section main body
205
. A light-receiving holder
216
houses a light-receiving element
220
, such as a photodiode PD or the like. As can be seen from
FIG. 21
, the optical axis of the light-emission element
221
and the optical axis of the light-receiving element
220
are arranged so as to cross each other in the center of a smoke detecting space and at an angle of, for example, 70°. Here, reference numeral
228
designates an infrared LED for test purpose, and
232
designates a plate member having a slit formed therein.
As shown in
FIG. 22
, the above-described smoke detector is built by means of assembling together the terminal board
203
having fitting hardware
209
fixed thereon; the shield case
204
; packing
207
, the printed board
208
; the smoke detecting section main body
205
; the smoke detecting section cover
211
; and the exterior cover
201
.
In many cases, the insect screen
214
used in a commonly employed smoke detector is made of metal. As shown in
FIG. 22
, the insect screen
214
is provided so as to cover the smoke detecting section cover
211
constituting the labyrinthine elements of the smoke detecting section. In order to attain an improvement in ease of production and the strength of a smoke detector, an insect screen is integrally formed with a smoke detecting section during a molding operation (see Japanese Patent Publication No. Hei 5-78879).
Such an insect screen used with the smoke detector is formed by means of rolling a flat metal plate into a ring shape, hexagonal holes being formed in the metal plate, and attaching the thus-rolled metal plate to a position around labyrinthine elements of a smoke detecting section or integrally embedding the metal plate into the smoke detecting section during a molding operation. Thus, production of the smoke detector becomes complicated.
In the case of a smoke detector in which an insect screen is integrally formed with labyrinthine elements of a smoke detecting section, the insect screen cannot be replaced after production, even when replacement is desired. In such a case, a smoke detecting cover constituting labyrinthine elements or a smoke detecting section main body must be replaced inconveniently. Another problem of the smoke screen is that insects which favor narrow areas sometime intrude holes of the insect screen.
SUMMARY OF THE INVENTION
The present invention has been conceived in light of such drawbacks of the commonly used smoke detector, and it is an object of the present invention to provide a smoke detector which is easy to build and is provided with a low-cost insect screen, as well as an insect screen for use with the smoke detector.
The present invention provides a smoke detector which includes a smoke detecting section defining a smoke detecting space and detects occurrence of fire by detection of smoke flowing into the smoke detection space, the sensor comprising:
an insect screen which is formed from a soft material of mesh structure and is arranged around the smoke detecting section.
The smoke detecting section is open toward the periphery and the bottom, and the insect screen is arranged so as to fully cover the periphery of the smoke detecting section and the open bottom of the smoke detecting section. The insect screen is made from permeable fabric woven from soft metal fiber or chemical fiber. Alternatively, fiber impregnated with a repellent is used as the insect screen. The insect screen is fixedly sandwiched between an interior circumferential edge of an exterior cover and an exterior circumferential edge of a smoke detecting main body.
Thus, permeable cloth woven from fiber is used as the insect screen. In contrast with a commonly employed insect screen made by means of etching a metal plate, the fabric insect screen has a higher airflow permeability. In a case where a repellent is applied to an insect screen, since the insect screen is made of fabric, the fiber is sufficiently impregnated with a repellent, thus exhibiting an insect-proofing effect over a long period of time. Even when meshes are slightly wide, the insect-proofing effect prevents intrusion of insects. and does not have any special fixing structure. Hence, the insect screen can be readily removed by means of removal of only the exterior cover. Thus, easy removal and replacement of an insect screen is implemented.
The present invention also provides an insect screen for preventing intrusion of insects into a smoke detecting space of a smoke detector. The insect screen is characterized by being made of permeable fabric woven from metal or chemical fiber. As mentioned above, so long as permeable cloth woven from fiber is used as an insect screen, a higher airflow permeability can be attained as compared with a case where a commonly employed insect screen is made from a metal plate through etching. So long as a repellent is applied to fiber, the fiber is sufficiently impregnated with a repellent. Thus, an insect-proofing effect can be exhibited over a long period of time. Further, even in a case where meshes are slightly wide, the insect-proofing effect an be exhibited over a long period of time. Further, even in a case where meshes are slightly wide, the insect-proofing effect prevents intrusion of insects into the insect screen.
REFERENCES:
patent: 4124298 (1978-11-01), Steele
patent: 4206366 (1980-06-01), Marsocci et al.
patent: 4439683 (1984-03-01), Dobrzanski
patent: 4851819 (1989-07-01), Kawai et al.
patent: 5399864 (1995-03-01), Igarashi et al.
patent: 6057774 (2000-02-01), Venzant
patent: 6195014 (2001-02-01), Sakuri et al.
patent: 2 277 376 (1994-10-01), None
patent: 2270803 (1990-11-01), None
patent: 5-78879 (1993-10-01), None
patent: 10241073 (1998-09-01), None
patent: 11016064 (1999-01-01), None
Hochiki Corporation
Sughrue & Mion, PLLC
Wu Daniel J.
LandOfFree
Smoke detector, and insect screen does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Smoke detector, and insect screen, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Smoke detector, and insect screen will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3124871