Dust cover

Abstract

To enable a cover to be easily removed from a smoke detector without scattering dust or dirt, and to enable a cover to fully function as a cushioning material when attached to the smoke detector and packed in a box. [Solution] The dustproof cover 10 covers the outside of the smoke detector 12 including the smoke inlet 1210, and comprises a cover main body 18 which is open at the top facing the smoke detector 12 to be attached, legs 20 formed on the cover main body 18 so as to protrude downwardly below the underside of the cover main body 18, multiple fitting recesses 22 formed on the side of the cover main body 18 which are circular in plan view and protrude inward at predetermined intervals, and fitting claws 24 which are formed protruding further inward from predetermined fitting recesses 22 and fit into the smoke inlet 1210 of the smoke detector 12, and the dustproof cover 10 can be removed from the smoke detector 12 by applying a rotational force to the legs 20 in a vertical direction as an axis, thereby releasing the engagement of the fitting claws 24.

Description

[Technical field]

[0001] The present invention relates to a dust cover for a smoke detector. [Background technology]

[0002] Traditionally, smoke detectors are installed in the ceilings of buildings during construction work, etc., but construction sites are prone to generating dust and dirt, which can enter the smoke detector through the smoke inlet, causing the insect screen to become clogged or affecting the detection sensitivity of the smoke detection section and reducing the detection function. Therefore, a dust cover is attached to the smoke detector before it is used to prevent dust and dirt from entering through the smoke inlet, and the dust cover is removed from the smoke detector when construction is completed and the smoke detector is to be used (Patent Document 1).

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

[0004] The process from manufacturing the dust covers to installing the smoke detectors is, for example, as follows: First, the dust covers manufactured by the dust cover manufacturer are stacked and packed in a packaging box, and then delivered from the dust cover manufacturer to the smoke detector manufacturer. After that, one dust cover is removed from the stack and attached to a smoke detector, and the smoke detector with the dust cover attached is packed in a packaging box and transported to the construction site, where the smoke detector with the dust cover attached is removed and installed on the ceiling, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 6-314386 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, when removing the dust cover from the smoke detector, a dedicated removal tool with a tip shape corresponding to the removal engagement part formed on the bottom surface of the dust cover is required, and there is the inconvenience of not preparing a dedicated removal tool for removing the dust cover. Also, instead of using a removal tool that fits into the groove formed on the bottom surface of the dust cover, it is possible to remove the dust cover by hooking a hook-shaped removal tool on the peripheral groove between the extension part that protrudes outward from the periphery of the recess of the dust cover and the recess, but in this case, when removing the dust cover, dust and dirt attached to the dust cover are blown up and enter the smoke detector through the smoke inlet.

[0007] In addition, there is a risk of dust and dirt accumulating on the outer extension of the dust cover, and even when the dust cover is rotated to remove it from the smoke detector, there is a risk that the dust and dirt accumulated on the outer extension will enter the interior of the smoke detector through the smoke inlet when the dust cover is removed.

[0008] In addition, although the removal engagement portion formed on the bottom surface 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 are in close contact with each other, and when the top surface of an adjacent smoke detector packed in a packaging box comes into contact with the bottom surface of the dust cover, which is in close contact with the bottom surface of the smoke detector, it cannot be said that the shock to the smoke detector is sufficiently mitigated, and its function as a cushioning material is weak.If additional cushioning material is required as needed, the packaging work will be time-consuming.

[0009] To provide a dust cover which can be easily removed from a smoke detector without scattering dust or dirt, and which functions adequately as a cushioning material when attached to the smoke detector and packed in a box. [Means for solving the problem]

[0010] (Dust cover) The present invention is a detachable dust cover for a smoke detector, A cover body portion that covers the outside of the smoke detector including the smoke inlet and has an open upper side that faces the smoke detector to be installed; A leg portion formed on the cover body portion so as to protrude downward from a lower surface of the cover body portion; a fitting portion that fits into the smoke inlet when the dust cover is attached to the smoke detector; Equipped with A feature of this structure is that by applying a rotational force to the legs around the vertical axis, the engagement of the fitting parts is released, allowing the dust cover to be removed from the smoke detector.

[0011] (Top opening of the main body cover) The cover body has an open upper surface.

[0012] (Fitting Structure) The fitting part is A plurality of fitting recesses are formed on a side surface of the cover body so as to protrude inward at predetermined intervals in an annular shape in a plan view; A fitting claw portion is formed by protruding further inward from the predetermined fitting recess and is inserted into and fitted into the smoke inlet of the smoke detector; Equipped with When a rotational force is applied to the legs, the engagement of the engagement claws of the engagement part is released, allowing the dust cover to be removed from the smoke detector.

[0013] (Multiple formed legs) The leg portions are formed on the cover body portion at predetermined intervals and in an annular shape in a plan view.

[0014] (Detail of multiple formed legs) The legs are formed at four locations on the cover body at predetermined intervals in a circular shape in a plan view.

[0015] (Anti-rollover structure of dust cover) When placing a smoke detector equipped with a dust cover on a designated installation surface, the legs are formed on the cover body so that the smoke detector is supported at three points: two adjacent legs out of the multiple legs and the side of the cover body, allowing the smoke detector to be placed horizontally with the top surface of the smoke detector at a designated angle to the designated installation surface.

[0016] (Horizontal angle) The vertical length of the legs is set so that when the smoke detector equipped with the dust cover is placed horizontally, the angle between the top surface of the smoke detector and the designated installation surface is a specified angle within the range of 60 degrees to 75 degrees. Effect of the Invention

[0017] (Dust cover effect) The present invention is a dustproof cover that can be attached and detached to a smoke detector, and comprises a cover main body that covers the outside of the smoke detector including the smoke inlet and has an open upper side that faces the smoke detector to be attached, legs formed on the cover main body so as to extend downward below the underside of the cover main body, and an engaging part that engages with the smoke inlet when the dustproof cover is attached to the smoke detector.The dustproof cover is designed so that by applying a rotational force about the vertical axis to the legs, the engaging part is released and the dustproof cover can be removed from the smoke detector.Therefore, no dedicated removal tool is required to apply a rotational force to the dustproof cover when removing it from the smoke detector; the dustproof cover can be removed from the smoke detector simply by pushing the legs with a rod-shaped member that is long enough to reach the legs and applying a rotational force. In addition, when the dust cover is removed from the smoke detector, the dust cover is not deformed more than necessary by impact, and dirt and dust adhering to the dust cover do not fly up, so it is possible to reliably prevent dirt and dust from entering through the smoke inlet and causing clogging of the insect screen or affecting the detection sensitivity of the smoke detection section and reducing the detection function.

[0018] In addition, when the dust cover is attached to the smoke detector and packed in a packaging box, the legs that protrude downward from the underside (bottom) of the cover main body abut the top surface of the adjacent smoke detector, rather than the underside of the cover main body, making it difficult for impacts to be transmitted to the smoke detector, thereby enhancing its function as a cushioning material.

[0019] (Effect of the opening on the top of the main body cover) In addition, since the entire upper side of the cover main body is open, there is no area for dirt and dust to accumulate near the opening for attaching the smoke detector, and when the dust cover is removed from the smoke detector, dirt and dust can be prevented from entering the interior through the smoke inlet of the smoke detector.

[0020] (Effect of fitting structure) The fitting portion includes a plurality of fitting recesses formed on the side of the cover body portion in a ring shape at predetermined intervals in a plan view and projecting inward, and a fitting claw portion formed projecting further inward from the predetermined fitting recesses and fitting into the smoke inlet of the smoke detector, and when a rotational force is applied to the leg portion, the fitting claw portion of the fitting portion is released from the fitting, and the dust cover can be removed from the smoke detector. The fitting claw portion that enters the smoke inlet restricts the vertical and rotational movement of the dust cover, making it possible to reliably attach the dust cover to the smoke detector. When removing the dust cover, a rotational force that exceeds the rotational force restricted by the fitting claw portion is applied to the leg portion, thereby releasing the fitting of the fitting claw portion and allowing the dust cover to be removed.

[0021] (Effect of multiple legs) In addition, the legs are formed in multiple places, for example four places, on the cover main body at a predetermined interval in a ring shape when viewed in a plane, so that the number of legs to which rotational force can be applied increases, making it easier to remove the dust cover and further enhancing its function as a cushioning material.

[0022] (Effect of the dust cover's rollover prevention structure) In addition, when a smoke detector equipped with a dust cover is placed against a designated installation surface, the legs are formed on the cover main body so that the smoke detector is supported at three points: two adjacent legs out of the multiple legs and the side of the cover main body, allowing it to be placed horizontally with the top surface of the smoke detector at a designated angle to the designated installation surface.Therefore, when a smoke detector equipped with a dust cover is packed horizontally in a packaging box, the smoke detector can be maintained in this horizontal position without tipping over, making it possible to improve the workability of tasks such as packing a smoke detector that require it to be placed horizontally.

[0023] (Effect of horizontal angle) In addition, the vertical length of the legs is set so that when the smoke detector fitted with the dust cover is placed horizontally, the angle between the top of the smoke detector and the designated installation surface is a specified angle within the range of 60 degrees to 75 degrees, thereby ensuring both stability when placed horizontally and visibility of the underside (bottom) of the smoke detector fitted with the dust cover. [Brief description of the drawings]

[0024] [Figure 1] 1 is an explanatory diagram showing a smoke detector installed on a ceiling and a dust cover not attached. [Diagram 2] FIG. 2 is an explanatory diagram showing a smoke detector with a dust cover attached. [Diagram 3] 11 is an explanatory diagram showing the process of removing the dust cover from the smoke detector. FIG. [Figure 4] FIG. 2 is an explanatory diagram showing the smoke detector with the dust cover removed. [Diagram 5] FIG. 4 is an explanatory diagram showing the dust cover as viewed from the front. [Figure 6] FIG. 4 is an explanatory diagram showing a dust cover as viewed from above. [Figure 7] FIG. 4 is an explanatory diagram showing the dust cover as viewed from diagonally below. [Figure 8] FIG. 4 is an explanatory diagram showing the dust cover as viewed diagonally from above. [Figure 9]1 is an explanatory diagram showing a schematic diagram of a state in which a dust cover is attached from below a smoke detector. FIG. [Figure 10] 11 is an explanatory diagram showing a schematic diagram of a fitting structure of the dust cover in a fitted state; FIG. [Figure 11] 1 is an explanatory diagram showing a smoke detector with a dust cover attached in a boxed state and in a horizontally placed state; FIG.

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a dust cover according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment.

[0026] [Basic Concept of the Embodiment] First, a basic concept of the embodiment will be described. The embodiment generally relates to a dust cover to be attached to a smoke detector having a smoke inlet.

[0027] Here, a "smoke detector" is installed in a designated monitoring area and monitors for fires by detecting smoke generated in the monitoring area, and a "monitoring area" is the area that is monitored by a smoke detector, and is an outdoor or indoor space of a certain extent, and is a concept that includes areas such as rooms, corridors, and staircases of a building.

[0028] The "dust cover" is a cover that is attached to a smoke detector to prevent dust and dirt from entering through the smoke inlet, and is removed from the smoke detector when monitoring with the smoke detector begins. In addition, the "dust cover" also functions as a cushioning material when the smoke detector is packed in a box while still attached to it.

[0029] The "dust cover" of the embodiment is characterized by having a "cover main body," "legs," and an "engaging portion," and by applying a rotational force to the legs around the vertical axis, the engaging portion is released, allowing the dust cover to be removed from the smoke detector.

[0030] The "main cover part" covers the outside of the smoke detector, including the smoke inlet, and is open on the upper side, which faces the smoke detector to be attached. Note that in the specification and claims, the "upper side of the dust cover" is the side of the smoke detector to be attached, and the opposite side is the "lower side," defining the up-down direction, and "height" refers to the length in the up-down direction.

[0031] In addition, the "cover main body" is open on the entire upper side, and does not have a flange that protrudes outward from around the upper opening, like the outer extension of the dust cover in Patent Document 1, thereby preventing dust and dirt from accumulating near the opening.

[0032] The "legs" are formed on the cover main body so as to protrude downward below the underside of the cover main body, and as long as it is possible to apply a rotational force to the legs, their arrangement and number are arbitrary, and include, for example, multiple legs, specifically four legs, formed on the cover main body at a predetermined interval in a ring shape when viewed in a plane.

[0033] In addition, the "legs" are the parts that come into contact with the top of the adjacent smoke detector when a dust cover is attached to the smoke detector and packed into a packaging box, functioning as a cushioning material and determining the stacking position when dust covers are stacked.

[0034] The "fitting portion" fits into the smoke inlet when the dust cover is attached to the smoke detector, and includes, for example, an "fitting recess" and an "fitting claw portion." The "fitting recess" is formed on the side of the cover body portion in a circular shape in a plan view, protruding inward at a predetermined interval, and the "fitting claw portion" is formed protruding further inward from a predetermined fitting recess, and fits into the smoke inlet of the smoke detector by entering it, and the "fitting recess" and "fitting claw portion" are provided on the dust cover in correspondence with the position of the smoke inlet of the smoke detector.

[0035] The number of "fitting recesses" is arbitrary, but may include, for example, four fitting recesses formed at a predetermined interval in a ring shape in a plan view, or two fitting recesses formed opposite each other, at positions different from the positions where the legs are formed. Also, the "fitting claws" do not necessarily need to be formed in all fitting recesses, and for example, when four fitting recesses are formed at a predetermined interval in a ring shape in a plan view, they may be formed in all four fitting recesses, or may be formed in two opposing fitting recesses.

[0036] For this reason, no dedicated removal tool is required to apply a rotational force to the dust cover when removing it from the smoke detector, and the dust cover can be removed from the smoke detector simply by pushing the legs with a rod-shaped member long enough to reach the legs and applying a rotational force. Furthermore, when removing the dust cover from the smoke detector, the dust cover does not deform more than necessary due to impact, and dust and dirt adhering to the dust cover does not fly up, so it is possible to reliably prevent dust and dirt from entering through the smoke inlet and causing clogging of the insect screen or affecting the detection sensitivity of the smoke detection unit and reducing the detection function.

[0037] In addition, when the dust cover is attached to the smoke detector and packed in a packaging box, the legs that protrude downward from the underside (bottom) of the cover main body come into contact with the top surface of the adjacent smoke detector, rather than the underside of the cover main body, making it difficult for impacts to be transmitted to the smoke detector, thereby enhancing its function as a cushioning material.

[0038] In addition, the "legs" are formed on the cover body so that, when the smoke detector equipped with the dust cover is placed on a designated installation surface, the legs are supported at three points: two of the multiple legs and the side of the cover body, allowing the smoke detector to be placed horizontally with the top surface of the smoke detector at a designated angle to the designated installation surface, and preferably the vertical length (height) is set so that when the smoke detector equipped with the dust cover is placed horizontally, the angle between the top surface of the smoke detector and the designated installation surface is a designated angle within the range of 60 degrees to 75 degrees.

[0039] Furthermore, when a smoke detector equipped with a dust cover is placed horizontally, the angle between the top of the smoke detector and the designated installation surface refers to the angle on the bottom side of the smoke detector (the side on which the dust cover is attached).

[0040] Specific embodiments will be described below. In the specific embodiments shown below, the "fitting portion" includes an "fitting recess" and an "fitting claw portion", the "leg portion" is formed at four locations on the lower side of the cover body, and the "fitting recess" and the "fitting claw portion" are formed at two opposing locations on the side of the cover body between the legs.

[0041] [Specific details of the embodiment] The dust cover according to the embodiment will be described below. a. Installing and removing dust covers on smoke detectors b. Dust cover structure c. Fitting structure of dust cover for smoke detector c1. Fitting structure of smoke inlet and dust cover of smoke detector c2. Release of the mated state due to the mating structure d. Anti-tipping structure for smoke detectors equipped with dust covers e. Modifications of the present invention

[0042] [a.Attaching and removing dust covers to smoke detectors] First, the installation (attachment) and removal of the dust cover on the smoke detector will be explained with reference to Fig. 1, which shows the smoke detector installed on the ceiling and the dust cover without being attached, Fig. 2, which shows the smoke detector with the dust cover attached, Fig. 3, which shows the work of removing the dust cover from the smoke detector, and Fig. 4, which shows the smoke detector with the dust cover removed.

[0043] Here, in the description of Fig. 1, the XYZ directions are directions perpendicular to each other, and specifically, when viewed from the front (front face) at a position where one fitting recess 22 provided in the dust cover 10 and one smoke inlet 1210 of the smoke detector 12 are at the center, the X direction is the left-right direction, the Y direction is the up-down direction, and the Z direction (not shown in Fig. 1) is the front-back direction. Also, the +X side in the X direction is the right side, the -X side is the left side, the +Y side in the Y direction is the upper side, the -Y side is the lower side, the +Z side in the Z direction is the front side, and the -Z side is the rear side. This also applies to Figs. 2 to 6, 9, and 10.

[0044] As shown in Fig. 1, for example, a ceiling member 14 is provided on the ceiling of a construction site of a building, 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 in the ceiling member 14. In addition, the smoke detector 12 is delivered to the construction site with the dust cover 10 attached, and is attached to the detector base 13 with the dust cover 10 attached. It is of course also possible to attach the dust cover 10 to the smoke detector 12 after the smoke detector 12 is installed in the detector base 13.

[0045] A plurality of smoke inlets 1210 are formed at predetermined intervals around the lower periphery of the smoke detector 12, and in this embodiment, the smoke inlets 1210 are formed in eight separate locations. An insect screen is arranged in a ring shape on the inside of the smoke inlet 1210, and a smoke detection space is formed inside the insect screen with a ring shape labyrinth structure (a light-shielding structure that allows smoke to pass but blocks external light).

[0046] A scattered light detection structure is provided in the smoke detection space, in which the light emitting unit and the light receiving unit are arranged so that the light receiving optical axis of the light receiving unit forms a predetermined scattering angle with respect to the light emitting optical axis of the light emitting unit, and the smoke detector 12 is capable of detecting a fire based on the signal level of the received light signal detected by the light receiving unit receiving the scattered light generated by the irradiation of light from the light emitting unit onto smoke that has flowed into the smoke detection space.

[0047] The dust cover 10 includes a cover body 18, legs 20, a fitting recess 22, and fitting claws 24.

[0048] 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, has an opening on the entire upper side, and is shaped like a bowl with a circular opening on the upper side corresponding to the shape of the smoke detector 12. In addition, the cover body 18 does not have a flange that protrudes outward from the periphery of the upper opening 1810, unlike the outer extension of the dust cover of Patent Document 1, which was taken up as a conventional dust cover, and therefore has a structure in which dust and dirt are less likely to accumulate near the upper opening 1810 of the dust cover 10.

[0049] The legs 20 are formed at four locations on the underside of the cover body 18, rotated 90° in a circular shape in a plan view, so as to protrude downward from the lower surface (bottom surface) of the cover body 18.

[0050] The fitting recesses 22 are formed protruding inward at two locations, front and rear, on the side surface of the cover body 18 between the legs 20, and fitting claws 24 are formed in the fitting recesses 22 protruding further inward from the fitting recesses 22, and the fitting claws 24 abut and fit into the lower end side of the smoke inlet 1210 of the smoke detector 12, making it possible to maintain the dust cover 10 attached so as not to fall off naturally from the smoke detector 12 installed on the ceiling member 14, as shown in Fig. 2. The detailed structure of the dust cover 10 will be described later.

[0051] Furthermore, by attaching the dust cover 10 to the smoke detector 12, it is possible to reliably prevent dirt and dust from the construction site from entering the inside of the smoke detector 12 through the smoke inlet 1201 and causing clogging of the insect screen or affecting the detection sensitivity of the smoke detection section and reducing the detection function.

[0052] Furthermore, when construction work on a building is completed and use of the smoke detector 12 begins, the dust cover 10 is removed from the smoke detector 12. In removing the dust cover 10, for example, as shown in Fig. 3, when the tip of a rod-shaped member 16 having a predetermined length that reaches the dust cover 10 attached to the smoke detector 12 is brought into contact with any of the legs 20 provided at four locations on the dust cover 10 and a force is applied to rotate the dust cover 10 around the Y axis, the dust cover 10 comes off the smoke detector 12 and falls naturally as shown in Fig. 4.

[0053] [b. Dust cover structure] Next, the structure of the dust cover will be described. In this description, reference will be made to Fig. 5, which shows the dust cover as viewed from the front, Fig. 6, which shows the dust cover as viewed from the top, Fig. 7, which shows the dust cover as viewed from diagonally below, and Fig. 8, which shows the dust cover as viewed from diagonally above. In Figs. 6 to 8, a reference position marker 15 indicated by "▼" is shown as a guide for the position of the dust cover 10 in Fig. 5 when viewed from the front.

[0054] The dust cover 10 is manufactured, for example, by a vacuum molding method using a known convex mold, and has a thickness of about 0.2 to 0.3 mm. Furthermore, since the leg parts 20 are easily thinned by deep drawing when manufactured by the vacuum molding method and have reduced strength, the leg parts 20 may be formed with a plurality of reinforcing ribs extending in the height direction (vertical direction) to increase the strength of the leg parts 20.

[0055] Moreover, the cover main body 18, leg portions 20, mating recesses 22 and mating claw portions 24 that the dust cover 10 has are basically as described above, and as shown in FIG. 6, the mating recesses 22 and mating claw portions 24 are formed in two locations, on the front and rear sides.

[0056] Here, it is fully possible to maintain the dust cover 10 attached so that it does not fall off the smoke detector 12 naturally by engaging the engaging claws 24 formed in two places on the front and rear sides, but 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 can be formed in two places, for example on the left and right sides.

[0057] In addition, as shown in Figures 6 to 8, by forming the legs 20 at four locations on the underside of the cover main body portion 18, a circular bottom surface 26 is formed in the center of the bottom surface of the cover main body portion 18, and connected bottom surfaces 28 are formed extending in four directions from the circular bottom surface 26 toward the fitting recess 22.

[0058] [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, reference will be made to Fig. 9, which shows a schematic diagram of the state in which the dust cover is attached from the underside of the smoke detector, and Fig. 10, which shows a schematic diagram of the fitting structure of the dust cover in a fitted state. Figs. 9 and 10 show the dust cover 10 in cross section as seen from the right side, where the fitting recess 22, the fitting claw portion 24, and the smoke inlet of the smoke detector 12 can be seen, and the cut end surface portion of the dust cover 10 is shown by a thick line to make the dust cover 10 and the smoke detector 12 easier to understand.

[0059] (c1. Fitting structure of smoke inlet and dust cover of smoke detector) First, the fitting structure between the smoke inlet of the smoke detector and the dust cover will be described.

[0060] The smoke inlet ports 1210 are formed at eight locations at predetermined intervals on the truncated cone-shaped side formed at the bottom of the smoke detector 12, and in Figures 9 and 10, two smoke inlet ports 1210 facing each other in the front-to-back direction located on the Z axis are shown.

[0061] The dust cover 10 has an engagement recess 22 and an engagement claw portion 24 as an engagement structure that fits into the smoke inlet 1210, and as mentioned above, the engagement recess 22 and the engagement claw portion 24 are formed in two locations, on the front and rear sides of the cover main body portion 18.

[0062] The mating claw portion 24 protrudes inward from the protruding inner surface 2212 of the mating recess 22, and when the dust cover 10 is attached from below the smoke detector 12, it fits into the smoke outlet 1210 as shown in Figure 10, regulating the rotational movement of the dust cover 10 around the Y axis and the vertical movement.

[0063] More specifically, the height h1 of the engaging claw 24 is configured to be the same as the height h2 of the smoke inlet 1210, and when the engaging claw portion 24 engages with the smoke inlet 1210, as shown in Figure 11, the upper end side of the engaging claw portion 24 abuts against the opening upper end surface 1212 of the smoke inlet 1210, and the lower end side of the engaging claw portion 24 abuts against the opening lower end surface 1214 of the smoke inlet 1210, so that vertical movement is restricted by the engaging claw portion 24.

[0064] Moreover, the rotational movement around the Y-axis is restricted by one of the side ends of the fitting claw portion 24 abutting against one of the side ends 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, and the 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 the rotational movement of the dust cover 10 exceeding this length is restricted by the fitting claw portion 24.

[0065] Furthermore, the height h1 of the engaging claw portion 24 and the height h2 of the smoke inlet 1210 are the same height, but since the dust cover 10 can be maintained attached to the smoke detector 12 as long as the lower end side of the engaging claw portion 24 abuts the opening lower end surface 1214 of the smoke inlet 1210, the height h1 of the engaging claw portion 24 may be made lower than the height h2 of the smoke inlet 1210.

[0066] (c2. Release of the mated state due to the mating structure) Next, release of the fitted state by the fitting structure will be described.

[0067] When removing the dust cover 10 from the smoke detector 12, that is, when releasing the engagement with the smoke inlet port by the engagement structure, the dust cover 10 is rotated around the Y axis relative to the smoke detector 12.

[0068] When the dust cover 10 is rotated around the Y axis relative to the smoke detector 12, one side end of the engaging claw portion 24 abuts one of the opening ends of the smoke inlet 1210, and when a rotational force exceeding the rotational force regulated by the engaging claw portion 24 is applied to the dust cover 10, the abutting one side end of the engaging claw portion 24 deforms so as to be pushed outward upon abutment with the opening end of the smoke inlet 1210, the engagement of the engaging claw portion 24 is released, and the dust cover 10 is removed from the smoke detector 12.

[0069] Furthermore, to apply a rotational force to the dust cover 10 that exceeds the rotational force restricted by the mating recess 22, as shown in Figure 3, it is sufficient to abut a rod-shaped member 16 against one of the legs 20 of the dust cover 10 and push it in the rotational direction, making it possible to remove the dust cover 10 from the smoke detector 12 without the need for a dedicated jig for removing the dust cover from the smoke detector.

[0070] [d. Anti-tip structure for smoke detectors equipped with dust covers] Next, the rollover prevention structure for a smoke detector equipped with a dust cover will be explained. In this explanation, reference will be made to Fig. 11, which shows a smoke detector equipped with a dust cover in a boxed state and in a horizontally placed state. Fig. 11(A) shows a smoke detector equipped with a dust cover in a boxed state, and Fig. 11(B) shows a smoke detector equipped with a dust cover in a horizontally placed state.

[0071] As shown in FIG. 11(A), the smoke detector 12 is packed in a packing box 42 with the dust cover 10 attached and is transported to a construction site. When the smoke detector 12 with the dust cover 10 attached is packed in the packing box 42, the smoke detector 12 is packed horizontally so that the top surface of the smoke detector 12 (the surface attached to the detector base 13) is at a predetermined angle with respect to the bottom surface of the packing box. At this time, the legs 20 formed on the dust cover 10 come into contact with the top surface of the smoke detector located next to it, and the dust cover 10 also functions as a cushioning material. Here, since there is no smoke detector on the inner part of the legs 20 and it is hollow, it has a structure with high cushioning properties, making it possible to enhance the function as a cushioning material.

[0072] Since there are cases in which the smoke detector 12 with the dust cover 10 attached is placed horizontally during packing operations, etc., as shown in Figure 11 (B), the legs 20 are formed at four points that serve as contact points with the workbench 44 (the installation surface on which the smoke detector 12 with the dust cover 10 attached is placed), and are supported at three points: two points P1, P2 and P3 near the side wall on the opening side of the cover main body 14.This allows the smoke detector 12 with the dust cover 10 attached to be kept placed horizontally without tipping over, thereby improving the workability of packing operations, etc.

[0073] Here, when the smoke detector 12 equipped with the dust cover 10 is placed horizontally on the workbench 44, the angle θ between the upper surface of the smoke detector 12 and the workbench 44 is set to a predetermined angle, for example, within the range of 45° to 75°, preferably within the range of 60° to 75°, by setting the height of the legs 20 so that the angle θ is a predetermined angle, for example, within the range of 45° to 75°, preferably within the range of 60° to 75°, in order to ensure both stability in the horizontally placed state and visibility of the underside (the side on which the dust cover 10 is attached) of the smoke detector 12 equipped with the dust cover 10.

[0074] [e. Variations of the Invention] In addition to the above-described embodiment, the dust cover of the present invention also includes the following modifications.

[0075] (leg) In the above embodiment, the legs are formed in four places on the underside of the cover main body, rotated 90° in a ring shape when viewed in a plane, but this is not limited to this, and the number of legs can be any number as long as it is possible to apply a rotational force around the Y axis to the dust cover 10, and one or more legs may be formed at any position on the cover main body.

[0076] Here, if one leg is formed on the main body cover, it will not function as the anti-rollover structure described above, but if two or more legs are formed on the main body cover, it will be able to function as an anti-rollover structure.

[0077] (Fitting recess and fitting claw) In addition, the number and positions of the mating recesses and mating claws correspond to the number and shape of the smoke inlet ports formed in the smoke detector 12. For example, the mating recesses and mating claws may be formed in three locations by rotating 120 degrees in a ring shape, in which case it will be possible to accommodate smoke detectors in which the number of smoke inlet ports 1210 is a multiple of three, such as three or six.

[0078] (others) Furthermore, the present invention includes appropriate modifications that do not impair the objects and advantages of the present invention, and is not limited to the numerical values ​​shown in the above embodiments. [Explanation of symbols]

[0079] 10: Dust cover 12: Smoke detector 1210: Smoke inlet 1212: Opening top end surface 1214: Opening bottom end surface 13; Sensor base 14: Ceiling material 15: Reference position marker 16: Rod-shaped member 18: Cover body 1810:Top opening 20: Legs 22: Fitting recess 2212: Overhanging inner surface 24: Interlocking claws 26:Circular bottom 28: Continuous bottom surface 42: Packing box 44: Workbench

Claims

1. A dust cover that is detachable from a smoke detector, A cover body portion that covers the outside of the smoke detector including the smoke inlet and has an open upper side that faces the smoke detector to be installed; A leg portion formed on the cover body portion so as to protrude downward from a lower surface of the cover body portion; a fitting portion that fits into the smoke inlet when the dustproof cover is attached to the smoke detector; Equipped with This dust cover is characterized in that by applying a rotational force to the legs around an axis in the vertical direction, the engagement of the engaging portions is released, allowing the dust cover to be removed from the smoke detector.

2. A dust cover that is detachable from a smoke detector, The dust cover is characterized in that the cover body has an opening on the entire upper surface.

3. The dust cover according to claim 1, The fitting portion is A plurality of fitting recesses are formed on a side surface of the cover body so as to protrude inward at predetermined intervals in an annular shape in a plan view; A fitting claw portion is formed by protruding further inward from the predetermined fitting recess and is inserted into and fitted into the smoke inlet of the smoke detector; Equipped with This dust cover is characterized in that, when a force in the rotational direction is applied to the leg portion, the engagement of the engagement claw portion of the engagement portion is released, allowing the dust cover to be removed from the smoke detector.

4. The dust cover according to claim 1, The protective cover is characterized in that the leg portion is formed in a ring shape in a plan view on the cover body at a predetermined interval.

5. The dust cover according to claim 4, The dust cover is characterized in that the legs are formed at four locations on the cover body at predetermined intervals in a ring shape when viewed in a plan view.

6. The dust cover according to claim 4, This dustproof cover is characterized in that, when the smoke detector equipped with the dustproof cover is placed on a designated installation surface, the legs are formed on the cover main body so that the smoke detector is supported at three points by two adjacent legs out of the multiple formed legs and the side of the cover main body, allowing the smoke detector to be placed horizontally with the top surface of the smoke detector at a predetermined angle to the designated installation surface.

7. The dust cover according to claim 6, A dust cover characterized in that the vertical length of the legs is set so that when the smoke detector equipped with the dust cover is placed horizontally, the angle between the top surface of the smoke detector and the specified installation surface is a specified angle within the range of 60 degrees to 75 degrees.

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