JPH0342545Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an assembly structure of an ion type smoke detector. (Prior Art) In a conventional sensor, the parts to be assembled into the housing do not have a block configuration, and each part is individually assembled and fabricated by performing complicated wiring inside the housing. (Problems to be Solved by the Invention) In the conventional sensor described above, the parts do not have a block configuration, so the assembly work efficiency of the sensor is poor, and there are many difficulties in maintenance management and inspection.
Therefore, from the viewpoint of workability, the interior had to be made wider, and it was not possible to make it smaller and thinner. The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an ion-type smoke detector that can be made smaller and thinner by simplifying the assembly structure of the detector. The purpose is to (Means for Solving the Problems) In order to achieve the above object, the ion type smoke detector of the present invention has a hollow substantially truncated conical shape, and has a plurality of smoke inflow channels at the center of the lower end of the inclined surface. A sensor cover having a protruding hollow cylindrical body having a through hole and a sensor base formed in a bottomed cylindrical shape constitute an outer housing member, and the sensor cover and the sensor base are small in size. Both have an engaging assembly structure using engaging protrusions provided on one side, and a gap C is formed between the upper end peripheral surface of the sensor cover and the inner wall of the sensor base, and the bottom surface of the sensor base is formed. A hooking fitting is arranged on the back side of the partitioning wall that communicates with an undercut portion provided around the partition wall and forming the bottom surface of the sensor base, and the hooking fitting is partitioned off with a screw screwed into the front side of the partitioning wall. A sensor base block is fixed to the wall, the power terminal penetrated through the partition wall is soldered to one end of the hook, and a shield plate is stacked and held on the front of the partition wall. The printed circuit board block attached to the block consists of a disk-shaped printed circuit board on which various electrical elements are wired, and a bottomed cylindrical ion chamber containing a radiation source placed and fixed in the center of the printed circuit board. , a shield cover is disposed along the inner surface of the sensor cover to cover at least the inner surfaces of the side wall, the inclined surface, and the bottom surface of the hollow cylindrical body of the sensor cover, and the shield cover is disposed along the inner surface of the sensor cover; The positioning assembly is performed by a through hole in the printed circuit board and a fixing rib integrally molded to project from the sensor base. It is configured by connecting to a potential. (Function) The ion type smoke detector configured as above is
Attach the hook to the rear side of the partition wall of the sensor base, stack the shield plate and insulating plate on the front side of the partition wall to form the sensor base assembly, and attach the electrical elements to the sensor base assembly. etc., a printed circuit board assembly with an ion chamber having a radiation source, etc. is installed, and the shield cover disposed on the sensor cover is attached to the sensor base together with the sensor cover via the engaging protrusion. Assembly work becomes easier, and the device can be made smaller and thinner. (Example) Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 to 9. In FIGS. 1 to 4, reference numeral 4 denotes a sensor base made of synthetic resin into a circular shape, and its hollow part is closed off by a roof-shaped partition wall 5 integrally molded in cross section. A plurality of fixing ribs 6 for fixing the printed board, each having an engaging portion 6a formed at a mid-high position, are protrudingly formed at equal intervals near the outer periphery of the lower end surface of the sensor, that is, the front surface of the sensor. Reference numeral 7 denotes an undercut portion formed at the outer peripheral end of the partition wall 5, and a through hole 8 that communicates with the upper and lower end surfaces of the partition wall 5, that is, the front and rear surfaces of the sensor, spanning the partition wall 5 and the inner wall of the sensor base 4 . is formed. In addition, the sensor base 4
An engaging protrusion 4a is formed at the lower end of the inner wall of the sensor cover 9 , which forms the sensor housing together with the sensor base 4 . 9a is engaged. The sensor cover 9 is molded from synthetic resin into a substantially truncated cone shape, and has an inclined surface 9b extending from the lower end of the mounting base on which the engaging protrusion 9a is formed, and a hollow cylindrical body 10 at the center of the lower end of the inclined surface 9b. is molded to protrude. A plurality of through holes 10a are formed on the side surface of the hollow cylindrical body 10.
are formed, and these through holes 10a communicate with a smoke intake port 12 formed in a shield cover 11 housed within the hollow cylindrical body 10. Reference numeral 10b denotes an engagement hole formed at the center of the lower end of the hollow cylindrical body 10, and a cap 13 having an annular projection 13a is mounted inside this engagement hole 10b. However,
The shield cover 11 is press-molded in substantially the same shape as the sensor cover 9 , and is provided with a plurality of upright pieces 11b formed by cutting and bending a plate surface at an intermediate position of the inclined surface 11a. An engagement convex portion 9c and an engagement hole 11c protrudingly formed on the inclined inner wall of the sensor cover 9 are provided approximately in the center between the sections 11b.
Reference numeral 14 denotes a ring-shaped insect repellent net formed by etching a thin stainless steel plate into a net shape, which is placed around the circumferential surface of the through hole 10a, and is sandwiched between the hollow cylindrical body 10 and the cap 13 and ultrasonically welded. is fixed to the sensor cover 9 by. Reference numeral 15 denotes a substantially disk-shaped shield plate, which is formed by cutting and raising an upright piece 15a with elasticity at the peripheral end.
This upright piece 15a is brought into contact with the upper end of the sensor cover 9 and is mounted between the partition wall 5 and the sensor cover 9 . Reference numeral 16 denotes a substantially disk-shaped insulating plate disposed directly below the shield plate 15 , and the shield plate 15 and the insulating plate 16 are attached to the partition wall 5 via screws 17 . Reference numeral 18 denotes a cylindrical printed circuit board, which is held by engaging the engaging portion 6a of the fixed rib 6 with a through hole 19 formed at its end, and various electrical elements E are wired on the front surface of this printed circuit board 18. ing. 20 is a disc-shaped cathode, and a plurality of mounting legs 2 are attached to the peripheral end of the cathode.
0a protrudes in the same direction, and the mounting legs 20a are fixed to the printed circuit board 18 by soldering. A radiation source 21 is sandwiched between a disc-shaped radiation source fixing plate 22 made of a stainless steel plate and the cathode 20, and is fixed by caulking the radiation source fixing plate 22 to the cathode 20. On the other hand, a ring-shaped back anode 23 made of a stainless steel plate is fixed to the back side of the printed circuit board 18. That is, the back anode 23 has a slit 23a formed on the end face of the leg part integrally formed by press working, and the leg part 24a of the front anode 24 is inserted into the slit 23a by passing through the insertion hole 18 of the printed circuit board 18. By twisting the upper end of this leg 24a and further soldering its base, it is firmly fixed, so that the radiation source 21 can be easily recovered even after the ionization type smoke detector is burnt out in the event of a fire. ing. The front anode 24 is formed by press-molding a stainless steel plate into a substantially truncated conical shape to constitute an ion chamber, and is housed within the sensor cover 9 . Others, 2
5 is a separator made of polyester film, and has a fitting hole 2 in the center for receiving the front anode 24.
6 is formed, and this separator 25 is connected to the front anode 24.
By attaching the separator plate 25 to the shield cover 11, the smoke that has entered the inside of the sensor is prevented from flowing out.In order to maintain this attached state, the separator plate 25 is engaged with an upright piece 11b formed on the shield cover 11. Retained. Reference numerals 27 and 27a are hook fittings which are attached to the partition wall 5 with screws 28, and 29 is a power terminal which is fixed to the hook fittings 27 and 27a by soldering.
30 is a substantially disk-shaped cover that closes the back surface of the sensor. The ion type smoke detector constructed in this way is assembled with the sensor base assembly shown in FIG.
The printed circuit board assembly shown in FIG.
The shield cover assemblies shown in the figures will be explained individually, and finally, their overall assembly will be explained. First, the sensor base assembly is attached to the hooks 27 and 2 on the back side of the partition wall 5 that constitutes the sensor base 4.
7a are arranged one on top of the other in the order of 27a and 27, and these are fixed to the partition wall 5 with screws 28 screwed in from the front side of the partition wall 5, and the power terminal 29 passed through the partition wall 5 is connected to the hooking metal fittings 27, 27a. After fixing by soldering to one end, hold the shield plate 15 and the insulating plate 16 on top of each other in this order on the front of the partition wall 5, and screw them into the partition wall 5 by screwing the screws 17 from the front of the insulating plate 16. It is assembled by fixing. Next, in the printed circuit board assembly, various electric elements E are wired on the front surface of the printed circuit board 18, the radiation source 21 is sandwiched between the radiation source fixing plate 22 and the cathode 20, and the radiation source fixing plate 22 is connected to the cathode 20. After caulking and fixing the cathode 2
0 mounting legs 20a are soldered and fixed to the printed circuit board 18, and the front anode 24 is held with the legs 24a facing upward from the front of the printed circuit board 18, and the legs 24a of the front anode 24 are fixed to the printed circuit board 18. It is inserted into the insertion hole 18a formed in 18. Then, the slits 23a of the back anode 23 are inserted into the legs 24a protruding from the back side of the printed circuit board 18, and the ends of the legs 24a are twisted and soldered to firmly fix them together. The substrate 18 is assembled by engaging and holding the substrate 18 with the engaging portion 6a of the fixing rib 6 through the through hole 19 thereof. The shield cover assembly also connects the end of the separator 25 to the upright piece 11b of the shield cover 11.
An engagement protrusion 9 formed on the sensor cover 9 is engaged and held in the engagement hole 11c of the shield cover 11.
c, and house the shield cover 11 in the sensor cover 9 . On the other hand, the sensor cover 9 has a ring-shaped insect screen 14 arranged in advance around the through hole 10a of the hollow cylindrical body 10, and is fixed by sandwiching it between the cap 13 and the base of the hollow cylindrical body 10. Leave it there. Of course, a series of operations such as attaching the insect screen 14 described above can also be performed after the shield cover 11 is housed. The overall assembly of each assembly thus assembled consists of fitting the front anode 24 of the printed circuit board assembly into the fitting hole 26 of the separator 25 of the shield cover assembly, and This is accomplished by engaging the engaging protrusion 9a with the engaging protrusion 4a in the sensor base 4 , and mounting the printed circuit board assembly and shield cover assembly on the sensor base 4 . In this way, the ion type smoke detector of the present invention can be made thinner because the sensor base and the sensor cover are engaged with each other by the engagement protrusions, and because each component is assembled into an assembly, it can be made smaller. It becomes possible to Moreover, since the periphery of the sensor base 4 maintains a completely smooth surface, the aesthetic appearance of the sensor is enhanced. (Effects of the invention) As explained above, the present invention has a hollow cylindrical body which has a hollow substantially truncated cone shape and has a plurality of through holes for smoke inflow, which is protruded from the center of the lower end of the inclined surface. A sensor cover and a sensor base formed in a cylinder shape with a bottom constitute an outer housing member, and the sensor cover and the sensor base are engaged with each other by an engagement protrusion provided on at least one side. The assembly structure is such that a gap C is formed between the upper peripheral surface of the sensor cover and the inner wall of the sensor base, and an undercut portion is provided around a partition wall forming the bottom surface of the sensor base. A hooking fitting is arranged on the back side of the partition wall forming the bottom surface of the sensor base, and the hooking fitting is fixed to the partition wall with a screw screwed from the front side of the partition wall, and the hooking fitting is fixed to the partition wall by penetrating the partition wall. A power terminal is soldered to one end of the hook, and a shield plate is stacked and held on the front of the partition wall to form a sensor base block.
The printed circuit board block attached to this sensor base block has a disk-shaped printed circuit board on which various electrical elements are wired, and a bottomed cylindrical ion chamber containing a radiation source is mounted in the center of the printed circuit board. A shield cover is placed along the inner surface of the sensor cover and covers at least the inner surfaces of the side wall, the inclined surface, and the bottom surface of the hollow cylindrical body of the sensor cover. The sensor base block is positioned and assembled by a through hole in the printed circuit board and a fixing rib integrally molded to protrude from the sensor base, and the shield plate and the shield cover are each located at approximately the outermost periphery. By making contact with each other, the components are connected to the same potential, and each component is assembled into an assembly, which makes it smaller and thinner.In addition, the recesses were removed from the circumferential surface of the sensor base, making it a completely smooth surface. , the aesthetic appearance of the sensor can be improved.

[Brief explanation of drawings]

Fig. 1 is a front view showing the appearance of one embodiment of the present invention, Fig. 2 is a bottom view of Fig. 1, Fig. 3 is a vertical sectional view of Fig. 1, and Fig. 4 is a plan view of Fig. 1. , FIG. 5 is an exploded perspective view of the sensor base assembly, FIG. 6 is an exploded perspective view of the printed circuit board assembly, FIG. 7 is an exploded perspective view of the shield cover assembly, and FIG.
The figure is an exploded perspective view showing the overall assembly situation of each assembly. 4 ...Sensor base, 4a...Engaging protrusion, 5...
Partition wall, 6... Fixed rib, 7... Undercut portion, 9 ... Sensor cover, 9a... Engaging protrusion, 1
1...Shield cover, 15...Shield plate, 1
8...Printed circuit board, 19...Through hole, 27, 27
a...Hanging metal fitting, 29...Power terminal.

Claims (1)

[Scope of utility model registration request] The sensor cover is shaped like a hollow truncated cone and has a hollow cylindrical body protruding from the center of the lower end of the inclined surface and has a plurality of through holes for smoke inflow, and the sensor base is formed in the shape of a cylinder with a bottom. The sensor cover and the sensor base constitute an outer housing member, and the sensor cover and the sensor base have an engagement assembly structure with an engagement protrusion provided on at least one side, and the upper end circumferential surface of the sensor cover and the sensor base A partition wall that forms a gap C between the inner wall of the sensor base and communicates with an undercut provided around the partition wall that forms the bottom surface of the sensor base, and that forms the bottom surface of the sensor base. Place a hook on the back of the partition wall, fix this hook to the partition wall with screws screwed in from the front of the partition wall, and solder the power terminal passed through the partition wall to one end of the hook to secure it. The sensor base block has a shield plate stacked and held on the front of the partition wall, and the printed circuit board block attached to this sensor base block is a disk-shaped printed circuit board on which various electrical elements are wired and A bottomed cylindrical ion chamber having a radiation source is placed and fixed at the center of the printed circuit board, and at least the side wall, inclined surface, and hollow cylindrical body of the sensor cover are disposed along the inner surface of the sensor cover. A shield cover is disposed to cover each inner surface of the bottom surface of the sensor, and the printed circuit board block and the sensor base block are positioned by fixed ribs integrally protruding from the through hole of the printed circuit board and the sensor base. 1. An assembly structure of an ion type smoke detector, wherein the shield plate and the shield cover are connected to the same potential by abutting substantially the outermost portions of the shield plate and the shield cover, respectively.