Dust cover

Abstract

To provide a dust cover that can be easily removed from a smoke detector without scattering dust or dirt. [Solution] A dustproof cover 10 that is detachably attached to a smoke detector 12 installed on a detector base 13, comprising: a cover body 18 whose entire surface on the detector base 13 side is open and covers the outside of the smoke detector 12 and is supported by the smoke detector 12; legs 20 that protrude from the opposite side of the open surface of the cover body 18 and are formed on the cover body 18 with their entire surface closed; and an inclined portion 21 that rotates the cover body 18 in a direction that allows the smoke detector 12 to be installed on the detector base 13 by downward pressure from the legs 20 onto the inclined portion 21, thereby releasing the support of the cover body 18 and releasing the dustproof cover 10 from the smoke detector 12.

Description

Technical Field

[0001] The present invention relates to a dust cover attached to a smoke detector.

Background Art

[0002] Conventionally, smoke detectors are installed on the ceiling of a building due to construction work or the like. However, during construction, dust and dirt are likely to be generated at the construction site, and the dust and dirt enter the interior from the smoke inlet of the smoke detector, causing clogging of the insect screen or affecting the detection sensitivity of the smoke detection unit and reducing the detection function. Therefore, before starting use, an operator attaches a dust cover to the smoke detector to prevent dust and dirt from entering through the smoke inlet, and when starting to use the smoke detector after the construction is completed, the dust cover is removed from the smoke detector (Patent Document 1).

[0003] In addition, in order to prevent the dust cover from falling off the smoke detector installed on the ceiling, the dust cover is provided with a fitting structure that fits into the smoke inlet. In Patent Document 1, as the fitting structure, an engaging projection is provided that protrudes inward from the side surface of the dust cover. By engaging (fitting) the engaging projection with the smoke inlet of the smoke detector, the dust cover is attached to the smoke detector, and by fitting a removal jig into the dust cover and rotating it, the engaging projection comes out of the smoke inlet and the dust cover can be removed from the smoke detector.

[0004] In addition, the process from the manufacture of the dust cover to the installation of the smoke detector is as follows, for example. First, the dust covers manufactured by the dust cover manufacturer are packed in a packing box in a stacked state and delivered from the dust cover manufacturer to the smoke detector manufacturer. Then, an operator removes one dust cover from the stacked dust covers and attaches it to the smoke detector, packs the smoke detector with the dust cover attached in a packing box and transports it to the construction site, and may take out the smoke detector with the dust cover attached at the construction site and install it on the ceiling or the like.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 6-314386 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, in Patent Document 1, when an operator removes the dust cover from the smoke detector, a special removal tool is required that has a tip shape corresponding to the removal engagement part formed on the bottom surface (top surface on the closed side) of the dust cover. This presents the inconvenience of having to prepare a special removal tool in order to remove the dust cover.

[0007] Alternatively, instead of using a removal tool that fits into a groove formed on the bottom surface of the dust cover, the worker can remove the dust cover by hooking a hook-shaped removal tool into the circumferential groove between the recess and the outer extension that protrudes outward from around the recess of the dust cover. However, in this case, when the dust cover is removed, dust and dirt attached to the dust cover will be stirred up, and these dust and dirt will enter the smoke detector through the smoke inlet.

[0008] Furthermore, dust and debris may accumulate on the outer surface of the dustproof cover, and even when removing the dustproof cover by rotating it from the smoke detector, there is a risk that the dust and debris accumulated on the outer surface may enter the smoke detector through the smoke inlet when the dustproof cover is removed.

[0009] Furthermore, although the removable engagement part formed on the bottom of the dust cover functions as a cushioning material, when the dust cover is attached to the smoke detector, the bottom surface of the dust cover and the bottom surface of the smoke detector (the side opposite to the side attached to the detector base) are in close contact. When the top surface of adjacent smoke detectors packed in a box (the side attached to the detector base) comes into contact with the bottom surface of the dust cover that is in close contact with the bottom surface of the smoke detector, it is difficult to say that the impact on the smoke detector is sufficiently mitigated. The cushioning function is weak, and if additional cushioning material is required as needed, the packaging process becomes time-consuming.

[0010] The purpose of this invention is to provide a dust cover that can be easily removed from a smoke detector without scattering dust or dirt. [Means for solving the problem]

[0011] (Dust cover) This invention is a dust cover that is detachably attached to a smoke detector installed on a detector base, The entire surface on the sensor base side is open, and the cover body is supported by the smoke detector, covering the outside of the smoke detector. A leg portion is formed on the cover body and protrudes from the opposite side of the opening surface of the cover body, With the smoke detector installed on the detector base, the inclined part rotates the cover body in a direction that installs the smoke detector onto the detector base when pressed from below, It is characterized by having the following features.

[0012] (Sloping part of the leg) The legs have inclined sections that, when pressed from below, rotate the cover body in a direction that positions the smoke detector on the detector base. The downward pressure on the legs releases the support of the cover body, and the dust cover is detached from the smoke detector.

[0013] (Formation of inclined section) The leg portion has an inclined portion formed on at least one side in the direction of rotation due to downward pressure.

[0014] (The fitting part of the cover body) The cover body is equipped with a fitting portion that fits into the smoke inlet of the smoke detector when supported by the smoke detector.

[0015] (Structure of the fitting part) The mating part is, Multiple fitting recesses are formed on the side of the main body of the cover, protruding inward in a ring shape at predetermined intervals when viewed from above, It is formed to project further inward from a predetermined fitting recess and has a fitting claw portion that fits into the smoke inlet of the smoke detector. and includes When the dust cover is removed from the smoke detector, the fitting of the fitting claw portion is released.

[0016] (Details of the inclined portion) The inclined portion is formed avoiding the fitting recess.

Effect of the invention

[0017] (Effect of the dust cover) The present invention is a dust cover that is detachably attached to a smoke detector installed on a detector base. The dust cover has a cover body portion that covers the outside of the smoke detector with the entire surface on the detector base side being open and is supported by the smoke detector, and a leg portion that protrudes from the opposite side of the opening surface of the cover body portion and is formed on the cover body portion. When the smoke detector is installed on the detector base, there is an inclined portion that rotates the cover body portion in the direction of installing the smoke detector on the detector base by pressing from below. By having these components, when an operator removes the dust cover from the smoke detector, there is no need for a dedicated removal jig to apply a force in the rotational direction to the dust cover. It is possible to remove the dust cover from the smoke detector simply by lightly applying a force in the rotational direction by pressing the leg portion with a rod-shaped member having a length that reaches the leg portion.

[0018] Also, when an operator attaches the dust cover to the smoke detector and packs it in a packing box, instead of the open side of the cover body portion, the leg portion that protrudes from the closed side of the cover body portion abuts against the bottom surface of the adjacent smoke detector, making it difficult for an impact to be transmitted to the smoke detector. Therefore, it is possible to enhance the function as a buffer material.

[0019] (Effect of the inclined portion of the leg portion) The feet are formed, for example, on at least one side in the direction of rotation of the cover main body part in the direction of rotating the smoke detector to be installed on the detector base by pressing from below. When the cover main body part is released from being supported by pressing downward on the feet, the attachment of the dust cover to the smoke detector is released. When an operator removes the dust cover from the smoke detector, by pressing the inclined part, the dust cover will not be deformed by excessive impact, and it is possible to reliably prevent dust and dirt attached to the dust cover from flying up.

[0020] (Effect of the structure of the fitting part) When the cover main body part is supported by the smoke detector, it has a fitting part that fits into the smoke inlet of the smoke detector. The fitting part includes a plurality of fitting recesses formed on the side surface of the cover main body part, protruding inward in an annular shape at a predetermined interval in plan view, and a fitting claw part formed by protruding further inward from a predetermined fitting recess and fitting into the smoke inlet of the smoke detector. When the dust cover is removed from the smoke detector, the fitting of the fitting claw part is released, and the vertical movement and rotational movement of the dust cover in the direction of rotation are restricted by the fitting claw part of the smoke inlet, enabling the operator to reliably attach the dust cover to the smoke detector. When removing the dust cover, by applying a rotational force in the rotational direction that exceeds the rotational force restricted by the fitting claw part to the feet, the fitting of the fitting claw part can be released and removed.

[0021] (Detailed effect of the inclined part) Since the inclined part is formed avoiding the fitting recesses, when demolding by vacuum forming (blister pack), the dust cover can be taken out without adhering to the mold, thus reducing costs.

Brief description of the drawings

[0022] [Figure 1] It is an explanatory diagram showing a smoke detector installed on the ceiling and an uninstalled dust cover. [Figure 2] It is an explanatory diagram showing a smoke detector with the dust cover attached. [Figure 3]This is an explanatory diagram showing how to remove the dust cover from a smoke detector. [Figure 4] This is an explanatory diagram showing a smoke detector with its dust cover removed. [Figure 5] This is an explanatory diagram showing the dust cover from the front. [Figure 6] This is an explanatory diagram showing the dust cover as viewed from above. [Figure 7] This is an explanatory diagram showing the dust cover viewed from a diagonal downward angle. [Figure 8] This is an explanatory diagram showing the dust cover viewed from a diagonal upward angle. [Figure 9] This is a schematic diagram illustrating how a dust cover is attached to the bottom of a smoke detector. [Figure 10] This is a schematic diagram illustrating the fitted state of the dust cover's fitting structure.

[0023] The following describes embodiments of the dust cover according to the present invention based on the drawings. However, the present invention is not limited to the following embodiments.

[0024] [Basic Concepts of the Embodiment] First, the basic concept of the embodiment will be explained. The embodiment generally relates to a dust cover to be attached to a smoke detector having a smoke inlet.

[0025] Here, a "smoke detector" is a device installed on a detector base in a designated monitoring area, which monitors for fires by detecting smoke generated in the monitoring area. The "monitoring area" is the area that is monitored by the smoke detector, and is a concept that includes a certain area of ​​outdoor or indoor space, such as rooms, corridors, and stairwells in a building.

[0026] The "dust cover" is a cover attached to the smoke detector to prevent dust and dirt from entering through the smoke inlet, and is removed from the smoke detector when monitoring by the smoke detector is started. The "dust cover" also functions as cushioning material when the smoke detector is packaged while still attached.

[0027] Furthermore, the "dust cover" of this embodiment comprises a "cover body," "legs," "inclined parts," and "fitting parts," and is characterized in that the fitting parts can be released by applying a rotational force with the vertical axis to the legs, thereby allowing the dust cover to be removed from the smoke detector.

[0028] The "cover body" covers the outside of the smoke detector, including the smoke inlet, and has an opening on the upper side, which is the side of the smoke detector mounted on the detector base, i.e., the entire surface on the detector base side of the smoke detector. In the specification and claims, the "upper and lower directions of the dust cover" are defined with the "upper side" being the smoke detector side to which it is mounted and the opposite side being the "lower side," and "height" refers to the length in the vertical direction.

[0029] Furthermore, the "cover body" has an open surface on the upper side (sensor base side), and unlike the outer portion of the dustproof cover in Patent Document 1, it does not have a flange that protrudes outward from around the upper opening, thus preventing dust and dirt from accumulating near the upper opening.

[0030] The "legs" are formed on the cover body so as to protrude from the closed side of the cover body, and their arrangement and number are arbitrary as long as it is possible to apply a rotational force to the legs. For example, this includes multiple legs formed on the cover body at predetermined intervals in a ring shape when viewed from above, specifically in four locations.

[0031] Furthermore, the "leg portion" has an inclined section that rotates the cover body in a direction that allows the smoke detector to be installed on the detector base, and the "inclined section" is formed on at least one side in the direction of rotation by downward pressure. Here, downward pressure is applied simply by pressing the inclined section of the leg portion with, for example, a rod-shaped member with a rounded tip, and this pressure makes it possible to remove the dust cover from the smoke detector.

[0032] Furthermore, the "leg portion" is the part that comes into contact with the top surface of an adjacent smoke detector when a dust cover is attached to a smoke detector and packed into a box. It functions as cushioning material and also defines the stacking position when dust covers are stacked.

[0033] The "fitting portion" is designed to fit into the smoke inlet when a dustproof cover is attached to a smoke detector, and for example, it comprises a "fitting recess" and a "fitting claw." The "fitting recess" is formed on the side of the cover body in a ring shape in plan view, with multiple recesses protruding inward at predetermined intervals. The "fitting claw" is formed further inward from the predetermined fitting recess and fits into the smoke inlet of the smoke detector. The "fitting recess" and "fitting claw" are provided on the dustproof cover corresponding to the position of the smoke inlet of the smoke detector.

[0034] Furthermore, the number of "fitting recesses" is arbitrary, but may include, for example, four recesses formed at predetermined intervals in a ring shape in a plan view, or two recesses formed at opposing locations, in positions different from where the legs are formed. Also, "fitting claws" do not necessarily need to be formed in all fitting recesses; for example, if four fitting recesses are formed at predetermined intervals in a ring shape in a plan view, the claws may be formed in all four fitting recesses, or in two opposing fitting recesses.

[0035] Therefore, when an operator removes the dust cover from the smoke detector, a special removal tool is not required to apply rotational force to the dust cover. Instead, the dust cover can be removed from the smoke detector simply by pushing the legs with a rod-shaped member, such as one with a rounded tip, that is long enough to reach the legs and apply rotational force. Furthermore, the inclined portion is formed to avoid the fitting recess.

[0036] Furthermore, when removing the dust cover from the smoke detector, the dust cover will not deform excessively due to impact, and dust and debris attached to the dust cover will not be blown around. This effectively prevents dust and debris from entering through the smoke inlet, causing clogging of the insect screen, affecting the detection sensitivity of the smoke detection unit, and reducing detection functionality.

[0037] Furthermore, when workers attach dust covers to smoke detectors and pack them into boxes, the legs protruding from the closed side of the cover body, rather than the open side, come into contact with the top surface of the adjacent smoke detector. This reduces the impact transmitted to the smoke detector, thus enhancing its function as a cushioning material.

[0038] The following describes a specific embodiment. In the specific embodiment shown below, the "fitting portion" comprises a "fitting recess" and a "fitting claw portion," the "leg portion" is formed at four locations on the lower side of the cover body, and the "fitting recess" and "fitting claw portion" are formed at two opposing locations on the side of the cover body between the legs.

[0039] [Specific details of the embodiment] The embodiments of the dust cover will be described in the following sections. a. Installation and removal of dust covers for smoke detectors. b. Structure of the dust cover c. Fitting structure of the dust cover for the smoke detector c1. Fitting structure of the smoke inlet and dust cover of the smoke detector c2. Release of the mating state by the mating structure d. Modified forms of the present invention

[0040] [a. Installation and removal of dust covers for smoke detectors] First, we will explain how to attach and remove the dust cover to the smoke detector. In this explanation, please refer to Figure 1, which shows a smoke detector installed on the ceiling with an unattached dust cover; Figure 2, which shows a smoke detector with a dust cover attached; Figure 3, which shows the process of removing the dust cover from the smoke detector; and Figure 4, which shows the smoke detector with the dust cover removed.

[0041] In the explanation of Figure 1, the X, Y, and Z directions are mutually orthogonal. Specifically, when viewing the front view from the position where one fitting recess 22 on the dust cover 10 and one smoke inlet 1210 of the smoke detector 12 are centered, the X direction is the left-right direction, the Y direction is the up-down direction, and the Z direction, which is not shown in Figure 1, is the front-back direction. Furthermore, in the X direction, the +X side is the right side and the -X side is the left side, in the Y direction, the +Y side is the upper side and the -Y side is the lower side, and in the Z direction, the +Z side is the front side and the -Z side is the rear side. This is the same in Figures 2 to 6, 9 and 10.

[0042] As shown in Figure 1, for example, a ceiling member 14 is provided on the ceiling of a building construction site, and a detector base 13 for installing a smoke detector 12 is attached to the ceiling member. The smoke detector 12 is mechanically and electrically connected to the detector base 13 by fitting it into the detector base 13 from below and rotating it, and is then installed on the ceiling member 14.

[0043] Furthermore, the smoke detector 12 is delivered to the construction site with the dust cover 10 attached, and will be mounted to the detector base 13 with the dust cover 10 attached. It is also possible to attach the dust cover 10 to the smoke detector 12 after it has been mounted to the detector base 13.

[0044] Multiple smoke inlets 1210 are formed at predetermined intervals around the lower side of the smoke detector 12, and in this embodiment, smoke inlets 1210 are formed in eight locations. In addition, an insect screen is arranged in a ring inside the smoke inlets 1210, and a smoke detection space is formed inside the insect screen, in which a labyrinth structure (a light-shielding structure that allows smoke to pass through but blocks external light) is arranged in a ring.

[0045] The smoke detection space is provided with a scattered light detection structure in which a light-emitting unit and a light-receiving unit are positioned such that the light-receiving unit's optical axis is aligned with the light-emitting unit's optical axis at a predetermined scattering angle. The smoke detector 12 can detect a fire based on the signal level of the received light signal detected by the light-receiving unit, which receives the scattered light generated by the irradiation of smoke from the light-emitting unit onto the smoke flowing into the smoke detection space.

[0046] The dust cover 10 comprises a cover body 18, legs 20, inclined portion 21, fitting recess 22, and fitting claw portion 24.

[0047] The cover body 18 covers the outside of the smoke detector 12, including the smoke inlet 1210, when the dust cover 10 is attached to the smoke detector 12, and has an open top surface. It has a bowl-like shape with a circular opening at the top to correspond to the shape of the smoke detector 12.

[0048] Furthermore, unlike the outer portion of the dust cover described in Patent Document 1, which was cited as a conventional dust cover, the main body of the cover 18 does not have a flange portion that protrudes outward from around the upper top opening 1810. Therefore, the dust cover 10 has a structure that makes it difficult for dust and dirt to accumulate near the top opening 1810.

[0049] The legs 20 are formed in four locations on the underside of the cover body 18, rotated 90° in a ring shape when viewed from above, so as to protrude below the underside (bottom) of the cover body 18, and the legs 20 are provided with inclined portions 21.

[0050] The fitting recesses 22 are formed inwardly at two locations on the front and rear sides of the cover body portion 18, which is located between the leg portions 20, and fitting claw portions 24 are formed in the fitting recesses 22, further protruding inward from the fitting recesses 22.

[0051] The fitting claw portion 24 abuts against the lower end of the smoke inlet 1210 of the smoke detector 12 and engages with it, so that the dust cover 10 remains attached to the smoke detector 12 installed on the ceiling member 14, as shown in Figure 2, and does not fall off naturally. The detailed structure of the dust cover 10 will be described later.

[0052] Furthermore, the dust cover 10 is attached to the smoke detector 12, which reliably prevents dust and debris from the construction site from entering the smoke detector 12 through the smoke inlet 1201, causing clogging of the insect screen, affecting the detection sensitivity of the smoke detection section, and reducing its detection function.

[0053] Furthermore, when the construction of the building is completed and the smoke detector 12 is put into use, the dust cover 10 is removed from the smoke detector 12. To remove the dust cover 10, for example as shown in Figure 3, a rod-shaped member 16 having a predetermined length that reaches the dust cover 10 attached to the smoke detector 12 is used. The tip of the rod-shaped member 16, for example, the rounded part, is brought into contact with one of the inclined parts 21 of the four legs 20 provided on the dust cover 10, and an upward force in the Y-axis direction is applied to the dust cover 10. This force is converted into a rotational force around the Y-axis by the inclined part 21, and as shown in Figure 4, the dust cover 10 detaches from the smoke detector 12 and falls naturally.

[0054] The inclined portion 21 has a slope that, when pressed from below, rotates the smoke detector 12 in a direction that allows it to be installed on the detector base 13. This slope may be curved or flat. Furthermore, the inclined portion 21 is formed to avoid the fitting recess 22 (without an undercut), so that the dust cover 10 can be removed without adhering to the mold during demolding in vacuum forming.

[0055] [b. Structure of the dust cover] Next, the structure of the dust cover will be explained. This explanation will refer to Figure 5, which shows the dust cover viewed from the front; Figure 6, which shows the dust cover viewed from above; Figure 7, which shows the dust cover viewed from a diagonal downward angle; and Figure 8, which shows the dust cover viewed from a diagonal upward angle. In Figures 6 through 8, a reference position marker 15, indicated by a "▼", is shown as a guide to the position of the dust cover 10 when viewed from the front in Figure 5.

[0056] The dust cover 10 is manufactured, for example, by a vacuum forming method using a known convex mold, and its thickness is approximately 0.2 to 0.3 mm. Furthermore, when the leg portion 20 is manufactured by vacuum forming, it is a part that is prone to thinning due to deep drawing, which reduces its strength. Therefore, multiple reinforcing ribs extending in the height direction (up and down direction) may be formed on the leg portion 20 to increase its strength.

[0057] Furthermore, the dust cover 10's cover body 18, legs 20, inclined portion 21, fitting recess 22, and fitting claw portion 24 are basically as described above, and as shown in Figure 6, the fitting recess 22 and fitting claw portion 24 are formed in two locations, on the front and rear sides.

[0058] Here, the engagement of the two fitting claws 24 formed on the front and rear sides is sufficient to maintain the state in which the dust cover 10 is attached so that it does not fall off the smoke detector 12 naturally. However, if it is desired to increase the fitting force of the dust cover 10 to the smoke detector 12, additional fitting recesses 22 and fitting claws 24 may be formed, for example, on the left and right sides.

[0059] Furthermore, as shown in Figures 6 to 8, since the legs 20 are formed at four locations on the lower side of the cover body 18, a circular bottom surface 26 is formed in the center of the bottom surface of the cover body 18, and a series of bottom surfaces 28 are formed that extend in four directions from the circular bottom surface 26 toward the fitting recess 22.

[0060] [c. Fitting structure of dust cover for smoke detector] Next, the fitting structure of the dust cover to the smoke detector will be described. In this description, please refer to Figure 9, which schematically shows the state in which the dust cover is attached from the bottom of the smoke detector, and Figure 10, which schematically shows the fitted state of the fitting structure of the dust cover. Figures 9 and 10 show the dust cover 10 in a cross-section viewed from the right side, where the fitting recess 22 and fitting claw portion 24 and the smoke inlet of the smoke detector 12 can be seen. To make the parts of the dust cover 10 and the smoke detector 12 easier to understand, the cut end face of the dust cover 10 is shown with a thick line.

[0061] (c1. Fitting structure of the smoke inlet and dust cover of the smoke detector) First, let's explain the fitting structure between the smoke inlet and dust cover of the smoke detector.

[0062] The smoke inlets 1210 are formed at predetermined intervals in eight locations on the frustoconical side surface of the lower part of the smoke detector 12. Figures 9 and 10 show two smoke inlets 1210 that are located on the Z-axis and are opposite each other in the front-to-back direction.

[0063] The dust cover 10 is equipped with a fitting recess 22 and a fitting claw portion 24 as a fitting structure that fits into the smoke inlet 1210. As described above, the fitting recess 22 and the fitting claw portion 24 are formed in two places on the front and rear sides of the cover body 18.

[0064] The fitting claw portion 24 protrudes inward from the protruding inner surface 2212 of the fitting recess 22, and when the dustproof cover 10 is attached from the bottom of the smoke detector 12, as shown in Figure 10, it fits into the smoke outlet 1210 and restricts the rotational movement and vertical movement of the dustproof cover 10 around the Y axis.

[0065] More specifically, the height h1 of the fitting claw 24 is configured to be the same as the height h2 of the smoke inlet 1210. When the fitting claw portion 24 is fitted into the smoke inlet 1210, as shown in Figure 10, the upper end of the fitting claw portion 24 abuts against the upper end surface 1212 of the opening of the smoke inlet 1210, and the lower end of the fitting claw portion 24 abuts against the lower end surface 1214 of the opening of the smoke inlet 1210, thereby restricting vertical movement by the fitting claw portion 24.

[0066] Furthermore, rotational movement around the Y-axis is restricted by one side end of the fitting claw portion 24 contacting one side end of the smoke inlet 1210. The width (length in the rotational direction) of the fitting claw portion 24 is slightly shorter than the width (length in the rotational direction) of the smoke inlet 1210. Rotational movement of the dust cover 10 is permitted by the length obtained by subtracting the width of the fitting claw portion 24 from the width of the smoke inlet 1210, but any rotational movement of the dust cover 10 exceeding that length is restricted by the fitting claw portion 24.

[0067] Although the height h1 of the fitting claw portion 24 and the height h2 of the smoke inlet 1210 are the same, if the lower end of the fitting claw portion 24 is in contact with the lower end surface 1214 of the opening of the smoke inlet 1210, the dustproof cover 10 can be attached to the smoke detector 12, so the height h1 of the fitting claw portion 24 may be lower than the height h2 of the smoke inlet 1210.

[0068] (c2. Release of the mating state by the mating structure) Next, we will explain how to release the mating state using the mating structure.

[0069] When the dust cover 10 is removed from the smoke detector 12, that is, when the fitting structure is released from its engagement with the smoke inlet, the worker rotates the dust cover 10 around the Y-axis relative to the smoke detector 12.

[0070] When the dust cover 10 is rotated around the Y-axis by the inclined portion 21, one side end of the fitting claw portion 24 comes into contact with one open side end of the smoke inlet 1210. Furthermore, when a rotational force exceeding the rotational force restricted by the fitting claw portion 24 is applied to the dust cover 10, one side end of the contacting fitting claw portion 24 deforms so as to be pushed outward by contact with the open side end of the smoke inlet 1210, releasing the fitting of the fitting claw portion 24, and the dust cover 10 is removed from the smoke detector 12.

[0071] Furthermore, in order to apply a rotational force to the dust cover 10 that exceeds the rotational force restricted by the fitting recess 22, as shown in Figure 3, the worker can simply press the rounded tip of the rod-shaped member 16 against one of the inclined portions 21 of the legs 20 of the dust cover 10 and push it upward. This makes it possible to remove the dust cover 10 from the smoke detector 12 without requiring a special jig for removing the dust cover 10 from the smoke detector 12.

[0072] [d. Variations of the present invention] Modified examples of the dust cover according to the present invention will now be described. In addition to the embodiments described above, the dust cover of the present invention includes the following modifications.

[0073] (leg) In the above embodiment, the legs and inclined portions are formed in four locations on the underside of the cover body, rotated 90° in a ring shape in a plan view. However, the embodiment is not limited to this, and the number of legs and inclined portions is arbitrary as long as it is possible to apply a rotational force around the Y axis from below to the dust cover. It is sufficient if one or more legs and inclined portions are formed at any position on the cover body.

[0074] (Matching recess and matching claw portion) Furthermore, the number and position of the fitting recesses and fitting claws correspond to the number and shape of the smoke inlets formed in the smoke detector. For example, the fitting recesses and fitting claws may be formed in three locations rotated 120° in a ring shape. In this case, it can accommodate smoke detectors with a multiple of three smoke inlets, such as three or six.

[0075] Furthermore, in this embodiment, the inclined portion is provided on one side in the direction of rotation due to downward pressure, but it may also be provided on both sides, for example.

[0076] (others) Furthermore, this invention includes appropriate modifications that do not impair its purpose and advantages, and also includes the above-mentioned modifications. The numerical values ​​shown in the embodiments do not limit the scope of this model. [Explanation of symbols]

[0077] 10: Dust cover 12: Smoke detector 1210: Smoke inlet 1212: Opening top end surface 1214: Opening bottom end surface 13; Detector base 14: Ceiling components 15: Reference position marker 16: Rod-shaped member 18: Cover body 1810:Top opening 20: Legs 21: Inclined part 22: Fitting recess 2212: Overhanging inner surface 24: Fitting claw portion 26: Circular base 28: Continuous bottom surface

Claims

1. A dust cover that is detachably attached to a smoke detector installed on a detector base, The entire surface of the sensor base side is open, and the cover body portion covers the outside of the smoke detector and is supported by the smoke detector, The leg portion, which protrudes from the opposite side of the opening surface of the cover body, is formed on the cover body. With the smoke detector installed on the detector base, the inclined portion rotates the cover body in a direction that installs the smoke detector on the detector base by pressing from below, A dust cover characterized by having the following features.

2. A dust cover according to claim 1, The leg portion has an inclined portion that rotates the cover body portion in a direction that installs the smoke detector on the detector base when pressed from below. A dust cover characterized in that downward pressure on the legs releases the support of the cover body and detaches the dust cover from the smoke detector.

3. A dust cover according to claim 2, The dust cover is characterized in that the leg portion has the inclined portion formed on at least one side in the direction in which it rotates due to downward pressure.

4. A dust cover according to claim 2, The dust cover is characterized in that the cover body portion is provided with a fitting portion that fits into the smoke inlet of the smoke detector when supported by the smoke detector.

5. A dust cover according to claim 4, The aforementioned fitting portion is, In plan view, the annular shape is provided at predetermined intervals and protrudes inward, and multiple fitting recesses are formed on the side surface of the cover body, A fitting claw portion is formed to protrude further inward from the predetermined fitting recess and to fit into the smoke inlet of the smoke detector, Equipped with, A dust cover characterized in that the engagement of the fitting claw portion is released when the dust cover is removed from the smoke detector.

6. A dust cover according to claim 5, The dust cover is characterized in that the inclined portion is formed to avoid the fitting recess.

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