JP5391112B2 - Alarm - Google Patents

Description

  The present invention relates to an alarm device installed on a wall surface or a ceiling surface.

  Conventionally, as an alarm device installed on a wall surface, a ceiling surface or the like, as described in Patent Document 1, for example, a front view circle that houses a sensor unit (in the literature, “detection unit”) that senses changes in the surrounding environment A case portion (“main body portion” in the literature) and a circular mounting base portion (“base portion” in the literature) having the same diameter as the main body portion, and the base portion is first fixed to the installation surface Later, there was one that supported and fixed the main body to the base.

  In Patent Document 1, as a configuration in which the main body portion is supported by the base portion, a case-side engagement portion formed in the main body portion by rotating the main body portion relative to the base portion (in the literature, “protruding member”). And a base side engaging portion (in the literature, “annular groove”) formed on the base portion are engaged in a circular radial direction to support the main body portion on the base portion. In order to align the main body and the base, the bottom of the main body is flared in the radial direction to form a guided part ("insertion protrusion" in the literature), which is inserted into the surface of the base. An annular guide portion (“side wall” in the literature) corresponding to the shape of the protrusion is formed. The protruding member is formed so as to protrude in the radial direction on the outer peripheral surface of the inserting protruding portion. An annular groove is formed on the inner peripheral surface of the side wall. And the guide groove which guides a raising member to an annular groove is formed in the internal peripheral surface of a side wall.

  According to this configuration, since the main body portion and the base portion have the same shape, it is easy to fit the insertion protrusion into the annular side wall. That is, the centering of the main body and the base is easy. Thereafter, while the main body portion is rotated with respect to the base portion, the protruding member is guided by the guide groove and is fitted into the annular groove. Further, the protruding member is press-fitted into the annular groove, and the main body portion can rotate while being securely held with respect to the base portion. Therefore, after installation, it is possible to change the sensing direction of the main body and to correct the inclination of the main body. That is, the protruding member and the annular groove act as an engaging member that holds the main body portion on the base portion, and also act as an angle adjusting member for the main body portion after engagement.

  Further, Patent Document 1 has a configuration in which a guide groove is not provided, a claw portion of an elastic body is provided instead of a projection member, and the claw portion is fitted into the annular groove by pushing the insertion projection portion into the side wall. It is disclosed. As a similar configuration, Patent Document 1 also discloses that an engaging protrusion is provided instead of a protruding member without providing a guide groove. The engaging protrusion is always urged radially outward and can be optionally retracted radially inward. With the engaging protrusion retracted radially inward, the insertion protrusion is inserted into the side wall, and the engaging protrusion protrudes radially outward again, so that the engaging protrusion is engaged with the annular groove. Match. Also in these, the nail | claw part and the protrusion part for engagement are the structures press-fitted in an annular groove.

JP 2010-33286 A

  By the way, there exists a possibility that a case part may rotate little with respect to an attachment base part by the external force, thermal deformation | transformation, etc. which were provided during aged use. In the alarm device described in Patent Document 1, the engagement between the projecting member and the annular groove is the engagement in the radial direction, and the holding and position adjustment of the case part is performed by a series of rotation operations. If the engagement member unexpectedly moves from the annular groove to the guide groove, there is a risk that it will fall as it is. Moreover, in the case of the structure using a nail | claw part, since a nail | claw part is an elastic body, there exists a possibility that it may deteriorate. If the claw portion deteriorates, the urging force of the claw portion may be weakened, or the claw portion itself may be deformed and come off from the annular groove. Further, in the case of the configuration using the insertion protrusion, the gripping part for withdrawing / retracting the insertion protrusion is always exposed on the outer peripheral surface of the main body.

  In view of the above circumstances, an object of the present invention is to provide an alarm device that can adjust the angle of the case portion after installation and that does not cause the main body portion to fall.

  The first characteristic configuration of the alarm device according to the present invention includes a case portion that houses a sensor portion that detects a change in the surrounding environment, an attachment base portion that can be fixed to an installation surface, and the case portion and the attachment base portion. Urging portions for urging in directions away from each other, and rotating the case portion relative to the mounting base portion while resisting the urging force of the urging portion, thereby rotating the circumference of the case portion The case portion can be attached to the mounting base portion by engaging a case side engaging portion formed in the case portion with a base side engaging portion formed in the mounting base portion in the direction, After the side engaging portion and the base side engaging portion are engaged, the case portion is configured to be rotatable with respect to the mounting base portion, and the case side engaging portion and the base side engaging portion are After the engagement, the case with respect to the mounting base It lies in having a resistance generating portion which confers resistance to the rotation of the parts.

  With this configuration, the case side engaging portion and the base side engaging portion are engaged in the rotation circumferential direction, and the case portion and the mounting base portion are separated from each other by the biasing force of the biasing portion. Always energized. Therefore, once the case portion is attached to the attachment base portion, the case portion does not come off the attachment base portion unless the case portion rotates against the biasing force of the biasing portion. Therefore, there is no possibility that the case part will fall unexpectedly. Further, after the case portion is attached, the resistance of the resistance generating portion is always applied to the rotation of the case portion. Therefore, the case part can be completely fixed to the attachment base part at a desired angle only by performing the same series of rotation operations as the case of attaching the case part. Moreover, the angle adjustment of the case part after installation is also simple.

  According to a second characteristic configuration of the alarm device according to the present invention, the resistance generating portion is a force that separates the case portion and the attachment base portion from each other, and the case portion by the urging force on the urging portion and the This is in that a force is generated to try to separate the case portion and the attachment base portion beyond the separation distance from the attachment base portion.

  With this configuration, the resistance force generated by the resistance generating portion is a force that separates the case portion and the mounting base portion from each other, and thus is a force that is orthogonal to the direction in which the case portion can rotate. Therefore, even if an external force is applied or the case part is deformed during use over time, the case part is unlikely to rotate unexpectedly. In addition, since the resistance generated by the resistance generating portion is a force that causes the urging portion to exceed the separation distance between the case portion and the mounting base portion due to the urging force, the case portion and the mounting base portion are once separated. After attaching the part to the attachment base part, there is almost no possibility of the case part rotating unexpectedly. Therefore, it can prevent reliably that a case part falls unexpectedly.

A third characteristic configuration of the alarm device according to the present invention is provided in the case portion, and restrains the base side engaging portion from moving relative to the side opposite to the case portion, and the base side engaging portion. A case side guide portion for guiding the relative rotation of the case portion,
Provided on the mounting base, restrains the case-side engaging portion from moving relative to the mounting base, and the case-side engaging portion rotates relative to the mounting base. A base side guide part for guiding the resistance, and the resistance generating part is provided in any one of the case part and the mounting base part, and the case side engaging part and the base side engaging part, A first resistance portion having a width corresponding to the rotatable range of the case portion after the engagement, and having a predetermined height on either side of the case portion and the mounting base portion, Provided on the other of the case part and the mounting base part, and has a predetermined height on either side of the case part and the mounting base part, and the case side engaging part and the base side After the engagement portion is engaged, the first resistance portion and A second resistance portion that is overlapped in plan view, and the sum of the height of the first resistance portion and the height of the second resistance portion is the case portion by the biasing force of the biasing portion and the The first resistor portion and the second resistor portion are configured so as to be larger than the separation distance from the mounting base portion.

  With this configuration, the case portion and the mounting base portion are separated by mutual restraint by the base side engaging portion and the case side guide portion, and by mutual restraint by the case side engaging portion and the base side guide portion. There is a limit to distance. That is, this limit separation distance is the separation distance between the case portion and the mounting base portion due to the urging force of the urging portion. On the other hand, the sum of the height of the first resistance portion and the height of the second resistance portion is larger than the separation distance between the case portion and the mounting base portion due to the urging force of the urging portion. Further, the second resistance portion is located at a position overlapping the first resistance portion in plan view after the case side engagement portion and the base side engagement portion are engaged. That is, when the first resistance portion and the second resistance portion are overlapped in plan view, the case portion and the mounting base portion are separated from each other beyond the limit separation distance, and the case side guide portion is separated. A resistance force is applied to the relative rotation of the base side engaging portion and the relative rotation of the case side engaging portion with respect to the base side guide portion. As a result, the case portion can be configured not to rotate insufficiently. Thus, holding the case part and adjusting the angle of the case part after installation can be realized only by devising the shapes of the case part and the mounting base part.

  According to a fourth characteristic configuration of the alarm device according to the present invention, the second resistance portion is provided in a protruding portion protruding in an outer circumferential direction from the outer peripheral portion of the mounting base portion, and the mounting base portion is installed in the protruding portion. It is in the point which provided the fixing | fixed part fixed to a surface.

  With this configuration, since the second resistance portion can be used to fix the mounting base portion to the installation surface, it is possible to prevent an increase in the number of parts and to prevent the shape of the mounting base portion from becoming complicated. .

  A fifth characteristic configuration of the alarm device according to the present invention is that the biasing portion is a leaf spring integrally formed with the case portion or the mounting base portion.

  With this configuration, the urging portion can be integrally formed with the case portion, so that it is not necessary to prepare a separate part and the installation work can be reduced.

(A) is a perspective view from the front direction of a smoke detector. (B) is a perspective view from the back direction of a smoke sensor. FIG. 3 is an exploded perspective view from the back side of the smoke detector. These are perspective views which show the relationship between the base fixed to the wall surface, and a case. FIG. 4 is a rear view when the case is supported on the base. These are figures which show the point when supporting a case on a base. These are figures which show the state of each part when a guide part is located in the 1st step part. These are figures which show the state of each part immediately after a guide part fits in the 2nd step part. These are figures which show the state of each part when engagement hooks engage. These are figures which show the state of each part when a protruding part has overlapped.

  Hereinafter, an embodiment in which the present invention is applied to a photoelectric smoke detector will be described with reference to the drawings. In FIG. 5, (a) is a front view when the case and the base are aligned, and (b) is a partial sectional view in front view showing the relationship between the guided portion and the guiding portion at that time. (C) is a longitudinal sectional view in FIG. 6 to 9, (a) is a rear view of the case and the base in each state, (b) is a partial cross-sectional view of the region (b) in FIG. (B) is a longitudinal cross-sectional view in the figure, (d) is a longitudinal cross-sectional view in the circumferential direction as viewed from the radially outward direction of the region (d) in (a) figure, and (e) is ( e) It is the longitudinal cross-sectional view of the circumferential direction which looked at the radial direction of the area | region. In FIG. 4, in order to facilitate understanding of the features of the present invention, the unevenness or the like expressed in other drawings is not expressed within a range that does not affect the configuration of the smoke detector. 5 to 9 are simplified for the same reason. The single-line arrows in the circumferential direction in FIGS. 5 to 9 represent the mounting rotation direction of the case, and are hereinafter simply referred to as “mounting rotation direction”. However, the mounting rotation direction is a relative rotation direction as viewed from the stand of the case, and is reversed when viewed from the stand of the base.

  In the following description, the surface opposite to the wall surface is defined as the front side (front side), and the surface on the wall surface side is defined as the back side (rear side).

[About overall configuration]
As shown in FIG. 1, the smoke detector allows inflow of smoke from the side peripheral surface, and has a square case portion (hereinafter referred to as “case 1”), a substrate 2, and a case portion in front view. And a photoelectric sensor part (hereinafter referred to as “sensor 3”) that can sense smoke flowing into the case part, and has a circular shape smaller than the square shape of the case part when viewed from the front, An attachment base portion (hereinafter referred to as “base 4”) that is fixed and to which the case portion can be attached is provided.

  The sensor 3 detects the smoke flowing into the case 1 and emits an alarm sound from the speaker 5 when the smoke concentration exceeds a preset threshold value. To stop the alarm sound, the alarm sound can be stopped by pressing an alarm stop button 6 disposed on the surface of the case 1. If the alarm is installed at a high place and the alarm stop button 6 is not reachable, the alarm sound is stopped even if the alarm stop string 7 that can be hung down from the case 1 is pulled.

  As shown in FIG. 2, the case 1 includes a base portion (hereinafter referred to as “rear case 1a”) on the rear side, a cover portion (hereinafter referred to as “front case 1c”) on the front side, a rear case 1a and a front portion. And a partition portion (hereinafter referred to as “intermediate case 1b”) that partitions the internal space of the case 1 surrounded by the case 1c in the front-rear direction. The front case 1c, the rear case 1a, and the intermediate case 1b are made of resin and are manufactured by injection molding. The case 1 houses a sensor 3, a substrate 2, a speaker 5, an alarm stop button 6, and the like.

  Although not shown, the sensor 3 includes a plurality of smoke inlets through which smoke can be introduced, a plurality of labyrinth-like wall portions juxtaposed via a gap so as to block light from the outside, and the interior of the sensor 3. And a light receiving unit for sensing light from the light emitting unit scattered by the smoke flowing into the sensor 3. Since this sensor 3 is already known, the mechanism of smoke detection will not be described here.

  As shown in FIG. 2, the sensor 3 is disposed on the substrate 2 and a speaker 5 is connected thereto. The board 2 is printed with an electric circuit (not shown) and provided with electronic parts (not shown), and controls smoke detection, alarm sound generation, and the like.

  The assembly of the case 1 will be briefly described. As shown in FIG. 2, the alarm stop button 6 is dropped into the front case 1 c from the back side, and then the substrate 2 is fitted into the front case 1 c together with the speaker 5 at a predetermined position. Subsequently, the intermediate case 1 b is fitted into the front case 1 c so as to cover the substrate 2. Protrusions (not shown in the figure) projecting inward are formed on the inner side surfaces of two arbitrary corners on the inside surface of the front case 1c. On the outer surface of the intermediate case 1b, protrusions (not shown) protruding outward are formed corresponding to the protrusions of the case 1c. When the intermediate case 1b is forcibly pushed in until the leading end surface of the rising portion of the intermediate case 1b contacts the back surface of the front case 1c, both protrusions get over each other and engage. Thereby, the intermediate case 1b is fixed to the front case 1c, and is integrated with the front case 1c. The intermediate case 1 b is formed with an opening having substantially the same diameter as the sensor 3, and the intermediate case 1 b does not interfere with the sensor 3.

  Next, the rear case 1a is fitted into the front case 1c so as to cover the intermediate case 1b and the sensor 3. Finally, screws are tightened from the rear side of the rear case 1a to fix the rear case 1a to the front case 1c. As described above, as shown in FIG. 1, the case 1 that is square in front view and square in side view is assembled.

[About the base]
As shown in FIG. 3, the base 4 is fixed to the wall surface prior to the case 1. The base 4 is made of resin and is manufactured by injection molding. As shown in FIG. 4, the base 4 has a circular shape. As shown in FIG. 3, a rising portion 12 is formed on the outer peripheral portion of the rear case 1 a, and the base 4 has a size inscribed in the inner surface of the rising portion 12. That is, the shape of the base 4 is a circular shape inscribed in the square shape of the case 1. Thus, it can be said that the case 1 is made compact by minimizing the case 1 relative to the base 4, and the case 1 is stabilized by maximizing the base 4 relative to the case 1. It can be said that this is a configuration that can be supported. Protrusions 41 projecting in the radially outward direction of the base 4 are formed at four locations on the outer periphery of the base 4. As shown in FIG. 3, the protrusion 41 is formed with a hole (a “fixing portion” according to the present invention) into which a fixing tool, for example, a gypsum board pin P can be inserted, via the four protrusions 41. The base 4 can be attached to the wall surface of the plaster board. The base 4 is also formed with a screw hole 44, which can be attached with a screw or the like.

[Attaching the case to the base]
A procedure for attaching the case 1 to the base 4 will be described. First, as shown in FIGS. 4 and 5, the case 1 is inserted into the guide portion 42 while the case 1 is rotated to the left and right with respect to the base 4 fixed to the wall surface W in advance. And the base 4 are aligned.

  As shown in FIG. 3, the guided portion 16 is integrally formed at the center of the rear case 1a so as to protrude rearward. The guide part 42 is integrally formed in the center part of the base 4 so as to be recessed on the back side. The guide part 42 is formed in a shape that follows the shape of the guided part 16, and the guided part 16 can be fitted therein. When the guided portion 16 is fitted into the guiding portion 42, the cores of the case 1 and the base 4 are aligned. When the case 1 is further rotated according to the guidance of the guide portion 42, the engagement hooks 18 provided on the rear outer peripheral portion of the rear case 1a are engaged with the engagement hooks provided on the front outer peripheral portion of the base 4 as shown in FIG. The case 1 can be attached to the base 4 by being engaged with 43 in the rotational direction.

  This point will be described in detail. As shown in FIGS. 3 and 4, the guided portion 16 has an annular shape when viewed from the front, and is formed with ribs 16 a projecting radially outward at two locations on the outer peripheral portion. The guide part 42 is a hole having a shape corresponding to the annular shape of the guided part 16 and penetrates from the front side to the back side of the base 4. Two first step portions 42 a and two second step portions 42 b are provided on the outer periphery of the guide portion 42. The second step portion 42b penetrates from the front side to the back side of the base 4, but the first step portion 42a is shallower than the second step portion 42b and does not penetrate. The outer diameters of the first step portion 42a and the second step portion 42b are matched with the outer diameter of the guided portion 16 including the rib 16a. The first step portion 42a and the second step portion 42b have a certain width in the circumferential direction and are continuous with each other. In the present embodiment, both the first step portion 42a and the second step portion 42b have a central angle of 60 °. That is, when the guided portion 16 is fitted into the first step portion 42a or the second step portion 42b, relative rotation in the circumferential direction of the guided portion 16 is allowed, but relative movement in the radial direction is prevented.

  That is, the relative rotation center of the case 1 and the base 4 and the relative rotation center of the guided portion 16 and the guide portion 42 coincide with each other. Although rotation is allowed, relative movement of the case 1 with respect to the base 4 is prevented.

  Further, since the first step portion 42a and the second step portion 42b have different depths, the guided portion 16 is changed from the first step portion 42a to the second step as shown in FIGS. When fitted into the portion 42b, as shown in FIG. 7C and FIG. 8C, the distance between the case 1 and the base 4 in the front-rear direction is reduced.

  As described above, the base 4 is provided with the four protrusions 41, and three of the protrusions 41 are in front due to the rotation of the case 1 with respect to the base 4 as shown in FIG. Projects from behind the case 1 or hides in view. Specifically, since the circular shape of the base 4 is inscribed in the square shape of the case 1, as shown in FIG. 6A, when the protruding portion 41 is positioned in the vicinity of the inscribed portion, the protruding portion 41 is in the case 1. It protrudes from behind and becomes visible. As shown in FIGS. 7A, 8A, and 9A, when the protrusion 41 is located in a space between a square shape and a circular shape, the protrusion 41 is hidden behind the case 1. . The position and range of the second step portion 42 b are set so as to correspond to the timing at which the protrusion 41 is hidden behind the case 1. As for the position and range of the first step portion 42a, when the guided portion 16 is located at a location near the second step portion 42b in the first step portion 42a, the protrusion 41 is hidden behind the case 1. It is set as follows.

  In addition, by rotating the case 1 with respect to the base 4, the guided portion 16 is fitted into the second step portion 42b from the first step portion 42a, and as shown in FIGS. 7 (a) to 8 (a). When 1 is rotated, as shown in FIGS. 7E to 8E, the engagement hook 18 and the engagement hook 43 are engaged.

  With the above configuration, when the case 1 is attached to the base 4, the circular portion of the base 4 is hidden behind the case 1, but the protrusion 41 is visible. That is, the center of the base 4 can be determined using the protrusion 41 as an index. Further, since the guided portion 16 is fitted into the guide portion 42, the case 1 and the base 4 can be easily aligned. Furthermore, since the range of the first step portion 42a and the second step portion 42b is set in a wide range corresponding to a central angle of 240 °, the alignment between the case 1 and the base 4 is easier. Since the protrusion 41 is hidden behind the case 1 after the engagement hooks 18 and 43 are engaged, the appearance after the smoke detector is installed is good.

  As described above, before the guided portion 16 is fitted into the second step portion 42b, that is, between the state of FIG. 6 and the state of FIG. To do. That is, in the state of FIG. 6, as shown in FIG. 6D, the rising portion 12 and the protruding portion 41 interfere, but in the state of FIG. 7, the rising portion 12 and the protruding portion 41 do not interfere. Therefore, when the guided portion 16 is fitted into the second step portion, the base 4 relatively sinks inside the case 1. Therefore, the thickness of the alarm device can be reduced when the wall surface is attached.

  Here, the engagement between the engagement hook 18 and the engagement hook 43 will be described in detail. As shown in FIGS. 3 and 4, guide rails 45 are formed at three locations on the outer peripheral portion of the front side of the base 4. The guide rail 45 is formed in a bag shape by raising the outer peripheral portion of the base 4 in the front direction and further bending it in the radially inward direction. The guide rail 45 has a radially inner surface and at least a surface on the upper side in the mounting rotation direction open. The engagement hook 43 is formed on the back side of the guide rail 45 and on the upper side of the mounting rotation direction.

  Further, on the back side of the rear case 1a, guide rails 19 are formed at three portions that can face the guide rail 45. The guide rail 19 rises from the rear case 1a in the back direction, and is further bent in the radially outward direction to form a bag shape. The guide rail 19 has a radially outer surface and at least a surface on the upper side in the mounting rotation direction open. The engagement hook 18 is formed on the front side of the guide rail 19 and on the upper side of the mounting rotation direction.

  The positions of the guide rail 19 and the guide rail 45 are set so that the engagement hook 18 and the engagement hook 43 are engaged after the guided portion 16 is fitted from the first step portion 42a to the second step portion 42b. is there. The lengths of the guide rail 19 and the guide rail 45 are set so that the guided portion 16 can be relatively rotated until it comes into contact with the end portion of the second step portion 42b opposite to the first step portion 42a.

  Further, as shown in FIGS. 3 and 7E, the base 4 is integrally formed with a leaf spring portion 46 that is inclined to the front side. The leaf spring portion 46 is disposed on the upper side of the mounting rotation direction with respect to the engagement hook 43. Accordingly, as shown in FIGS. 7A and 7E, the leaf spring portion 46 comes into contact with the back side of the guide rail 19 before the engagement hook 18 and the engagement hook 43 are engaged with each other. 1 is biased to the front side. The distal end portions of the engagement hook 18 and the engagement hook 43 are inclined, and when the case 1 is rotated in the mounting direction and the inclined portions start to overlap each other, along the inclined portion of the engagement hook 43 on the fixed side. The inclined portion of the engagement hook 18 is guided, and the case 1 approaches the wall surface side against the urging force of the leaf spring portion 46. When the engagement hook 18 and the engagement hook 43 get over each other, the case 1 is separated from the base 4 by the urging force of the leaf spring portion 46. Thereby, the engagement hook 18 and the engagement hook 43 are engaged. Since this engagement is in the circumferential direction, once the case is engaged, unless the case 1 is rotated in the removal direction while pushing the case 1 against the base 4 against the urging force of the leaf spring 46, the case 1 does not come off the base 4.

  After the engagement hooks 18 and 43 are engaged, the engagement hook 18 can smoothly slide along the front surface of the guide rail 45 as shown in FIGS. 8 (e) to 9 (e). The engaging hook 43 can smoothly slide along the back surface of the guide rail 19. In other words, the guide rails 19 and 45 guide the movement of the engagement hooks 18 and 43 in the circumferential direction, but prevent the case 1 from moving in the direction away from the base 4. Note that the separation between the case 1 and the base 4 due to the urging force in the front-rear direction of the leaf spring portion 46 is limited to the position where the engagement hooks 18 and 43 contact the guide rails 45 and 19.

  In this way, the smoke detector is installed on the wall surface. In addition, since case 1 is square shape by front view, the outer periphery four sides of case 1 become parallel or perpendicular | vertical with respect to the ceiling surface and floor surface of installation space. Therefore, it is easy to become familiar with the installation space as compared with the case of the circular shape.

[Changing the angle of the case after mounting to the base]
Since the case 1 according to the present invention has a quadrangular shape when viewed from the front, the inclination of the case 1 is particularly conspicuous when it is installed on a wall surface, as compared with a circular shape. Therefore, the smoke detector according to the present invention is configured so that the angle of the case 1 can be adjusted even after the case 1 is attached to the base 4. This angle adjustment will be described.

  As shown in FIGS. 3 and 4, a ridge 20 having a constant width in the circumferential direction is formed on the rear surface of the rear case 1 a on the relative rotation locus of the protrusion 41 after the engagement of the engagement hooks 18 and 43. An inclined portion 20 a is formed on the upper side of the protruding portion 20 in the mounting direction of the case 1. Further, the front side of the protrusion 41 is raised to form a raised portion 41a. The sum of the heights of the raised portion 20 and the raised portion 41a is set to be larger than the limit value of the separation distance between the case 1 and the base 4 due to the urging force of the leaf spring portion 46 described above. The circumferential length of the raised portion 20 is set to be the same as or larger than the range in which the case 1 can rotate after the engagement hooks 18 and 43 are engaged.

  In such a configuration, after the engagement hooks 18 and 43 are engaged, as shown in FIGS. 8 to 9, the case 1 is further rotated to ride the raised portion 20 on the raised portion 41 a (overlapping in plan view). ), The case 1 tends to be further separated from the base 4 against the restraint in the separation direction between the case 1 and the base 4 caused by the contact of the engagement hooks 18 and 43 and the guide rails 45 and 19. However, the case 1 and the base 4 cannot basically be separated because the relative movement in the front-rear direction is restricted. Therefore, elastic deformation occurs in at least one of the case 1 and the base 4 made of resin, and resistance to rotation of the case 1 is given by the restoring force. Therefore, the case 1 is positioned on the base 4 at any position while the raised portion 41 a is riding on the raised portion 20. In other words, after the case 1 is attached to the base 4, the posture of the case 1 can be freely adjusted while being fixed to the base 1. In addition, since the inclined part 20a is provided, the rising part 20 from the state of FIG.

  From the above, the guide rail 19 corresponds to the “case side guide portion” according to the present invention, the guide rail 45 corresponds to the “base side guide portion”, the leaf spring portion 46 corresponds to the “biasing portion”, and the bulge The portion 20 corresponds to a “first resistance portion”, and the raised portion 41a corresponds to a “second resistance portion”. Further, the engaging hook 18 and the guide rail 45, the engaging hook 43 and the guide rail 19, and the raised portion 20 and the raised portion 41a together constitute the “resistance generating portion” according to the present invention. .

[Another embodiment]
(1) In the above-described embodiment, the guided portion 16 has a convex shape and the guide portion 42 has a concave shape to form the first step portion 42a and the second step portion 42b. However, the present invention is not limited to this. . For example, the guided portion 16 may be formed in a concave shape to form a first step portion and a second step portion, and the guide portion 42 may be formed in a convex shape.
(2) In the above-described embodiment, the raised portion 20 as the first resistance portion is formed in the rear case 1a, and the raised portion 41a as the second resistance portion is formed in the protrusion 41. However, the present invention is not limited to this. Absent. For example, the protruding portion 41 may be widened in the circumferential direction to form a raised portion as the first resistance portion, and the raised portion as the first resistance portion may be formed in the rear case 1a.
(3) In the above-described embodiment, the three protrusions 41 serving as the index for alignment are provided, but it is sufficient that the number of the protrusions as the index is one or more. However, if there are two or more projections serving as indexes and they are spaced apart by 90 ° or more at the central angle, the position of the guide portion 42 that is the central portion of the base 4 is easy to predict and is suitable.
(4) In the above-described embodiment, the case 1 has a square shape inscribed by the circular shape of the base 4, but is not limited thereto. If the protrusion 41 is visible when the case 1 is attached to the base 4 and the protrusion 41 is hidden behind the case 1 before the engagement hooks 18 and 43 are engaged, for example, the front surface It may be a viewing rectangle, other polygonal shapes, a circular shape, an elliptical shape, or the like. In the above-described embodiment, the square shape of the case 1 is chamfered at the four corners in an R shape, but it may not be chamfered.
(5) In the above-described embodiment, the first step portion and the second step portion are provided, and the guided portion is fitted in the guide portion in two steps. However, the present invention is not limited to this. For example, it is good also as a structure which a to-be-guided part fits into a guide part in three steps or more or a continuous side.
(6) Although the above-mentioned embodiment showed the example which installs an alarm device in a wall surface especially, the alarm device installed in a ceiling surface may be sufficient.

  The present invention is not limited to smoke detectors, but can be applied to other alarm devices that detect changes in the surrounding environment, such as heat detectors and gas alarm devices.

1 Case (case part)
3 Sensor (Sensor part)
4 Base (mounting base)
18 Engagement hook (case side engagement part)
19 Guide rail (case side guide / resistance generator)
20 Raised part (first resistance part, resistance generation part)
41 Projection 41a Raised part (second resistance part / resistance generation part)
43 Engagement hook (base side engagement part)
45 Guide rail (underside guide / resistance generator)
46 Leaf spring (biasing part)
W Wall surface (installation surface)

Claims (5)

A case portion that houses a sensor portion that detects changes in the surrounding environment;
A mounting base that can be fixed to the installation surface;
An urging portion that urges the case portion and the mounting base portion in directions away from each other;
The case side engaging portion formed in the case portion in the rotation circumferential direction of the case portion and the attachment by rotating the case portion with respect to the attachment base portion while resisting the urging force of the urging portion. The case portion can be attached to the mounting base portion by engaging the base side engaging portion formed on the base portion,
After the case side engaging portion and the base side engaging portion are engaged, the case portion is configured to be rotatable with respect to the mounting base portion,
An alarm device comprising a resistance generating section that provides resistance to rotation of the case section with respect to the mounting base section after the case-side engaging section and the base-side engaging section are engaged.   The resistance generating portion is a force that separates the case portion and the mounting base portion from each other, and the case portion exceeds a separation distance between the case portion and the mounting base portion due to a biasing force of the biasing portion. The alarm device according to claim 1, wherein a force for separating the mounting base portion from the mounting base portion is generated. Provided in the case portion, restrains the base side engaging portion from moving relative to the opposite side of the case portion, and guides the base side engaging portion to rotate relative to the case portion. A case side guide portion to be
Provided on the mounting base, restrains the case-side engaging portion from moving relative to the mounting base, and the case-side engaging portion rotates relative to the mounting base. A ground side guide portion for guiding
The resistance generator is
Provided in any one of the case part and the mounting base part, and having a width corresponding to the rotatable range of the case part after the case side engaging part and the base side engaging part are engaged. A first resistance portion having a predetermined height on the other side of the case portion and the mounting base portion, and
The case part and the mounting base part are provided on the other side, and have a predetermined height on either side of the case part and the mounting base part, and the case side engagement part and the base A second resistance portion that is in a position overlapping with the first resistance portion in plan view after the side engagement portion is engaged,
The first resistance portion is configured such that the sum of the height of the first resistance portion and the height of the second resistance portion is greater than the separation distance between the case portion and the mounting base portion due to the biasing force of the biasing portion. The alarm device according to claim 2, wherein the second resistance portion is configured.   4. The second resistance portion is provided in a protruding portion that protrudes in an outer circumferential direction from an outer peripheral portion of the mounting base portion, and a fixing portion that fixes the mounting base portion to an installation surface is provided in the protruding portion. Alarm device described in.   The alarm device according to any one of claims 1 to 4, wherein the biasing portion is a leaf spring integrally formed with the case portion or the mounting base portion.

Images