JP7765283B2 - Sensors and Sensor Bases - Google Patents

Description

The present invention relates to a detector, such as a fire detector, and to the structure of a base for installing the detector.

Conventional fire detectors include smoke detectors that detect fires by detecting smoke, heat detectors that detect fires by detecting heat, and fire detectors that detect fires by detecting smoke. All types of fire detectors have a head with a sensor inside, and are installed facing downward on the ceiling or other surface of a building. The head also has multiple fins (partitions) and a unique structure (pillar) that protects the sensor, and is configured with an opening that allows ambient air to flow into the head (see, for example, Patent Documents 1 and 2).

Japanese Patent Application Publication No. 09-259376 Japanese Patent Application Laid-Open No. 2021-135924 Japanese Patent Application Publication No. 10-111988

When installing a fire detector with the above configuration, the installation location must be determined taking air flow into consideration. Meanwhile, in recent years, an increasing number of buildings have been constructed with exteriors and interiors that strongly reflect the architectural designer's wishes. As a result, fire detectors may be required to be installed in a way that does not detract from the interior design. Furthermore, in buildings such as rental buildings, the interior is often changed as tenants change, and the orientation of the detector may be specified to match the new interior design.

In addition, fire detectors are equipped with indicator lights that show their operating status. Fire detectors equipped with point-type indicator lights have a directional visibility, so they are often installed so that the operating indicator light faces a specific direction, such as the entrance.
An invention relating to a fire detector equipped with a point-light-emitting type indicator lamp is disclosed in, for example, Patent Document 3.

As a result, when initially installing a detector on a mounting surface such as a building's ceiling or wall, it was necessary to check the orientation by actually holding the detector against the installation location, secure the detector base, and then attach the detector itself to the detector base. Furthermore, if it was necessary to change the orientation of an installed detector after installation to align the orientation of the head's fins or openings with the interior design or to shift the angle position of the point-emitting indicator light, it was necessary to first remove the detector from the detector base that is fixed to the ceiling, etc., loosen the fixing screws of the detector base, adjust the orientation of the base, and then reattach the detector to the base. This process was time-consuming and required longer work times at dangerous heights, creating the problem of increased work time.

The present invention was developed in response to the above-mentioned issues, and its purpose is to provide a sensor and sensor base that allows the sensor base to be installed simply and quickly on the ceiling or other mounting surface of a building when first installing the sensor, and that also allows the orientation of an already installed sensor to be easily changed later.

In order to achieve the above object, the present invention provides:
A detector comprising a main body incorporating a sensor and an electronic circuit for making a determination based on a signal from the sensor, and a base for fixing the main body to a mounting surface of a building, wherein the main body is provided with a head having a plurality of openings through which the sensor faces or an operation indicator light that is lit by the electronic circuit,
At least one of the base and the main body portion or the main body portion and the head portion is rotatably connected, so that the circumferential angular position of at least the head portion can be changed relative to the base.

With a detector configured as described above, the detector base can be installed on a mounting surface such as the ceiling of a building without having to consider the orientation when initially installing the detector. This makes the installation of the detector base simple and quick, and the orientation of an already installed detector can be easily changed later. This allows the orientation of the fins and openings on the detector's head to be adjusted to match the interior design, improving the aesthetics of the building.

Preferably, the base is
a first base member having a fixing portion for fixing to an outer wall and a mounting surface of a building;
a second base member having an inner wall having a smaller diameter than the outer wall and a coupling means for coupling with the main body portion,
A first locking mechanism is provided between the outer wall and the inner wall, which allows or prevents rotation of the second base member relative to the first base member in the circumferential direction.

With the above configuration, by releasing the first locking mechanism, the first base member and the main body of the detector connected to it can be rotated relative to the second base member, thereby adjusting the orientation of the fins and openings in the head and the indicator light. Furthermore, in detectors equipped with point-light-emitting indicator lights, the angle of the indicator light can be shifted to make it easier to see from an entrance, for example.

Also, preferably, the first locking mechanism is
a notched portion formed along a circumferential direction on an outer surface of the inner wall;
a movable claw body having a claw that is inserted between the outer wall and the inner wall and that can be switched between an engaged state with the notched portion and a non-engaged state;
an operating portion that penetrates the outer wall and is partially exposed to the outside, and that changes the state of the movable claw;
It consists of:
With this configuration, the locking mechanism can be easily released and the main body of the sensor rotated by operating the operating part exposed on the outside of the outer wall of the base, thereby making it easy to set or change the orientation of the sensor.

Furthermore, preferably, the movable claw body comprises a support piece formed in an arc shape from a long plate-like elastic material, and a pair of claw bodies attached to both ends of the support piece and capable of engaging with the notched portion,
the operating portion is disposed such that an end portion opposite to a side that penetrates the outer wall and is exposed to the outside abuts against a center of a circumferentially outer surface of the support piece,
When the side that penetrates the outer wall and is exposed to the outside is pressed, the support piece is elastically deformed and the pair of claws are separated from the notched portion.
According to this configuration, the first locking mechanism can be provided in the relatively narrow gap between the outer wall and the inner wall.

Preferably, the main body includes a main body case that houses the sensor and the electronic circuit and has an opening at the center, and the head is formed separately from the main body case,
the head portion includes a plate-like lid portion, a plurality of pillar members each having one end connected to the lid portion and constituting the plurality of openings, and a flange portion having a diameter larger than a diameter of the openings and connecting the other ends of the plurality of pillar members to each other;
the head portion is attached to the main body case portion so that the plurality of pillar members are inserted into the openings, the lid portion is positioned outside the main body case portion, and the flange portion is positioned inside the main body case portion;
A second locking mechanism is provided between the flange and the edge of the opening, which allows or prevents the head portion from rotating in the circumferential direction relative to the main body case portion.
According to this configuration, by releasing the second locking mechanism, the head portion can be rotated relative to the main body portion of the sensor, thereby allowing the orientation of the fins and openings of the head portion to be adjusted.

Further, preferably, the second locking mechanism is
a notched portion formed along a circumferential direction on a surface of the flange portion facing an edge portion of the opening;
and a claw portion provided on the edge of the opening and capable of being changed between an engaged state with the notched portion and a non-engaged state.
According to this configuration, the second locking mechanism can be provided between the flange portion provided on the head of the sensor and the opening of the main body portion with a relatively simple structure.
In addition, by providing a biasing means between the surface of the flange portion opposite the notched portion and the opposing portion of the main body case portion, which biases the head portion in the direction in which the notched portion engages with the claw portion, the locked state can be reliably maintained.

The present invention has the advantage of providing a sensor and sensor base that allows the sensor base to be installed simply and quickly on the mounting surface of a building, such as the ceiling, when the sensor is first installed, and also allows the orientation of an already installed sensor to be easily changed later.

1A and 1B show an example of the configuration of a smoke detector to which the present invention is applied, in which (A) is an overall perspective view of the smoke detector, and (B) is a plan view showing the basic internal structure of a detector base that constitutes the smoke detector. 2 is a perspective view showing the configuration of the bottom surface of a detector main body that constitutes the smoke detector of FIG. 1. FIG. 1 is an exploded perspective view showing the internal structure of a sensor base in a first example of a smoke sensor according to an embodiment of the present invention. FIG. 4 shows the assembled state of the detector base that constitutes the smoke detector of the first embodiment shown in FIG. 3, where (A) is a plan view of the detector base, and (B) is a cross-sectional side view taken along line B-B in (A). 4A and 4B show the assembled state of the sensor base constituting the smoke sensor of the first embodiment shown in FIG. 3, in which FIG. 4A is a perspective view of the sensor base, and FIG. 4B is an enlarged perspective view of the main part of the sensor base. 1A and 1B show the structure of a locking mechanism constituting the smoke detector of the first embodiment, in which FIG. 1A is a plan view in an unlocked state, and FIG. 1B is a plan view in a locked state. FIG. 10 is a central cross-sectional view showing a second embodiment of the smoke detector according to the present invention. FIG. 10 is a perspective view showing the structure of a locking mechanism in a smoke detector according to a second embodiment.

Hereinafter, an embodiment in which the present invention is applied to a smoke detector will be described with reference to the drawings.
The smoke detector of this embodiment is a detector incorporating a smoke sensor (a pair of a light-emitting element and a light-receiving element) capable of detecting smoke generated by a fire. First, the basic configuration of the smoke detector of this embodiment will be described with reference to FIG.
1, a smoke detector is composed of a detector main body 10 and a detector base 20 to which the detector main body 10 is connected, and the detector base 20 is installed and fixed on the ceiling surface of a building or the like. In the following explanation, unless otherwise specified, the side that would be up when the smoke detector is installed on the ceiling surface of a building will be referred to as the lower side, and the side that would be down will be referred to as the upper side.

As shown in Figure 1(A), the detector body 10 consists of a dome-shaped outer cover 11 with a circular opening 11A formed in its center, and a head portion 12 that covers the opening 11A. A component called a dark box 13, which houses a smoke sensor and is located inside the outer cover 11, is partially protruding from the opening 11A. The head portion 12 consists of a disk-shaped lid 12a that covers the upper part of the dark box (16), and multiple fins 12b (four in the figure) that extend from the edge of the opening 11A and serve as legs supporting the lid portion 12a. Between the head portion 12 and the upper wall of the outer cover 11, multiple openings 13 are formed along the circumference, separated by the fins 12b and communicating with the opening 11A. These openings 13 function as smoke inlets that allow external smoke to enter the case.

As shown in Figure 1 (B), the sensor base 20 has a disk-shaped bottom wall 21 that is approximately the same size as the outer cover 11 of the sensor main body 10, a cylindrical outer wall 22 that stands up from the periphery of the bottom wall 21, and an inner wall 23 that is slightly smaller in diameter than the outer wall 22. The bottom wall 21 is provided with a number of connection terminals 24 for connecting the sensor base 20 to the sensor main body 10, wire insertion holes 25 through which wires connected to a circuit board housed within the sensor base 20 on which the smoke sensor is mounted are inserted, and a number of screw holes 26 through which fixing screws are inserted to fix the sensor base 20 to a connection part provided on the ceiling side.

In addition, a plurality of terminals 27 are provided on the bottom wall 21, which are electrically connected to the connection terminals 24 and into which the ends of the core wires of the electric wires inserted through the electric wire insertion holes 25 from the outside of the detector are inserted and electrically connected.
FIG. 1B shows a sensor base 20 having a conventional general configuration.

FIG. 2 shows the configuration of the bottom of the sensor main body 10 as viewed from below.
2, the bottom plate 14 of the sensor body 10 is provided with external terminals 15 to which the connection terminals provided on the sensor base 20 are respectively connected. The external terminals 15 include an inner terminal and an outer terminal having contact pieces bent toward each other, and the contact pieces are arranged so as to overlap each other. The connection terminal 24 of the sensor base 20 is inserted between the contact pieces of the inner terminal and the outer terminal, thereby electrically connecting the corresponding terminals of the sensor body 10 and the sensor base 20.

Furthermore, a peripheral wall portion 19 is provided on the peripheral edge of the bottom plate 14 of the sensor body 10, which fits into the gap between the outer wall 22 and inner wall 23 of the sensor base 20. When this peripheral wall portion 19 is fitted into the gap between the outer wall 22 and inner wall 23 of the sensor base 20 and rotated, the external terminals 15 of the sensor body 10 fit between the connection terminals 24 on the sensor base 20 and the bottom wall 21, thereby connecting the sensor body 10 to the sensor base 20 and simultaneously electrically connecting the corresponding terminals.

(First Example)
Figure 3 shows the structure of a sensor base 20 constituting a smoke sensor according to a first embodiment of the present invention. As shown in Figure 3, the sensor base 20 of the smoke sensor of this embodiment is composed of an outer base component 20A having a cylindrical outer wall 22, and an inner base component 20B having an inner wall 23, connection terminals 24, and wire insertion holes 25, and housed in close contact with the inside of the outer base component 20A. The sensor base 20 is thus composed of the outer base component 20A and the inner base component 20B so that the angular position of the inner base component 20B, which is coupled to the sensor, relative to the outer base component 20A can be changed by rotating the inner base component 20B in the circumferential direction.

Of the outer base constituent body 20A and inner base constituent body 20B, outer base constituent body 20A has a partial bottom wall 21A formed inside the lower end of the outer wall 22, with a large central opening 21a. A pair of bulges 21b that widen toward the opening 21a are provided in part of the partial bottom wall 21A, and screw holes 26 for inserting fixing screws are formed in each of the bulges 21b. Meanwhile, inner base constituent body 20B has a pair of bottom walls 21c formed with continuous openings from the center to the portions corresponding to the pair of bulges 21b, and connection terminals 24 and 27 are provided on the pair of bottom walls 21c, respectively.

4A and 4B show a state in which the inner base constituent body 20B is housed inside the outer base constituent body 20A. Of these, 4A is a plan view, and 4B is a cross-sectional side view taken along line BB in 4A.
As shown in Fig. 4(B), the component 20B is housed inside the outer base component 20A so that the lower end of the inner wall 23 of the inner base component 20B is in contact with the partial bottom wall 21A at the lower end of the outer base component 20A. Also, as shown in Figs. 4(A) and 4(B), a locking mechanism 30 is provided between the outer wall 22 of the outer base component 20A and the inner wall 23 of the inner base component 20B (the left side portion in the figure). When the locking mechanism 30 is released from its locked state, the inner base component 20B can be rotated in the circumferential direction, and when locked, it can be fixed in a state where rotation is prevented.

FIG. 5A is a perspective view showing a state in which the inner base component 20B is housed inside the outer base component 20A, and FIG. 5B is an enlarged perspective view of the locking mechanism 30.
As shown in Figure 5 (B), the locking mechanism 30 is composed of a fixed claw portion 31 provided on the outer peripheral surface of the inner wall 23 of the inner base component 20B, an arc-shaped movable claw body 32 inserted into the gap between the outer wall 22 of the outer base component 20A and the inner wall 23 of the inner base component 20B, and an operation button 33 for operating this movable claw body 32.

The fixed-side claw 31 provided on the outer peripheral surface of the inner wall 23 is configured with a jagged portion formed by forming a plurality of parallel V-grooves over a predetermined range on the outer surface of the inner wall 23 of the inner base constituent body 20B. The movable-side claw 32 is configured with an arc-shaped support piece 32A made of a long plate-like spring steel, and a pair of locking claws 32B provided on both ends of the support piece 32A and having jagged portions formed on the surfaces facing the inner wall 23 of the inner base constituent body 20B.
Furthermore, a recess 32a recessed inward is formed in the center of the support piece 32A, and the outer surface of this recess 32a is configured to come into contact with the rear end surface of the operation button 33 arranged to penetrate the outer wall 22 of the outer base constituent body 20A. Although not shown, a hole is provided in the outer wall 22 of the outer base constituent body 20A so that the head of the operation button 33 can be inserted therethrough.

6A, the operation button 33 is provided with a flange 33a for preventing it from coming off. The pair of locking claws 32B are pivotally attached to both ends of the support piece 32A by pins 34. The center of rotation of the pin 34 is provided in the center of the locking claw 32B, and serrations are formed on the side farther from the pin 34 than the recess 32a. When the operation button 33 is pressed with a finger, the support piece 32A is elastically deformed, and the serrations of the locking claw 32B and the fixed-side claw 31 disengage, thereby releasing the lock.
Furthermore, when the finger is released from the operation button 33, the support piece 32A returns to its original shape, and as shown in Figure 6 (B), the serrated portion of the locking claw 32B and the serrated portion of the fixed side claw portion 31 mesh with each other, thereby entering a locked state that prevents relative movement in the circumferential direction.

As described above, the sensor base 20 of this embodiment is composed of the outer base component 20A and the inner base component 20B, so that the angular position can be changed by rotating the inner base component 20B relative to the outer base component 20A, and since a locking mechanism 30 is provided between the two, the set angular position can be maintained.
Therefore, when initially setting the sensor at a predetermined position on the mounting surface, the outer base component 20A is first fixed to the mounting surface without worrying about the orientation of the sensor, i.e., the mounting angle of the sensor base 20, and then the locking mechanism 30 is released and the inner base component 20B is rotated to adjust the angle, so that the mounting angle of the sensor base 20 can be easily set to the desired orientation.
Furthermore, if there is a sensor already installed and you want to change the orientation of the sensor due to changes to the interior, etc., you can easily change the installation angle of the sensor base 20 to the desired orientation by first releasing the locking mechanism and rotating the inner base component 20B to adjust the angle.

(Second Example)
The structure of a smoke detector according to a second embodiment of the present invention is shown in Figure 7. As shown in Figure 7, in the smoke detector of this embodiment, the head portion 12 provided on the detector body 10 is formed as a separate component from the outer cover 11, and a flange portion 12c is provided at the lower end of the head portion 12.

The dark box 16 with the built-in smoke sensor is provided with a flange 16a that faces the inner edge of the opening 11A formed in the outer cover 11 at a predetermined distance, and the flange 12c of the head 12 is arranged so that it is inserted with a small gap between the flange 16a of the dark box 16 and the inner edge of the opening 11A of the outer cover 11. This allows the head 12 to rotate relative to the outer cover 11.
In Figure 7, the part marked with the reference numeral 17 is a ring-shaped indicator light made of a translucent material, and is configured to emit light by guiding light from a light-emitting element (LED) (not shown) mounted on a substrate 18 built into the sensor main body 10.

Furthermore, in the smoke detector of this embodiment, a locking mechanism is provided between the lower surface of the inner edge of the opening 11A of the outer cover 11 and the flange 12c of the head portion 12.
8 shows a specific example of a locking mechanism between the outer cover 11 and the head unit 12. As shown in Fig. 8, the locking mechanism in this embodiment is composed of a knurled portion 12d formed on the upper surface of the flange portion 12c of the head unit 12, a knurled portion 11d formed on the lower surface of the inner edge of the opening 11A of the outer cover 11, and a spring member (e.g., a leaf spring) (not shown) interposed between the flange portion 12c of the head unit 12 and the flange portion 16a of the dark box 16.

Therefore, when the head portion 12 is pushed downward against the spring force of the spring member, the serrated portion 12d on the head portion 12 disengages from the serrated portion 11d on the outer cover 11, releasing the locked state and allowing the head portion 12 to rotate. Then, when the head portion 12 is rotated to a predetermined angle and the pushing of the head portion 12 is stopped, the spring force pushes the head portion 12 upward, causing the serrated portion 12d on the head portion 12 to engage with the serrated portion 11d on the outer cover 11, thereby locking the head portion 12 and preventing it from rotating.

As described above, in the smoke detector of the second embodiment, the head portion 12 can be rotated relative to the outer cover 11. Therefore, if you want to change the orientation of the fins 12b of the head portion 12, i.e., the opening (smoke inlet) 13, to harmonize with the interior design, you can easily change the orientation of the fins (pillars) 12b of the head portion 12 without having to loosen the screws that secure the detector base and change the angle of the detector base, significantly reducing the time required to change the orientation of the fins.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments. For example, in the first embodiment, a locking mechanism that is released when the operation button is pressed is shown, but instead of such a locking mechanism, a locking mechanism that is released when the sensor body is pressed, as in the second embodiment, may be provided.
Furthermore, although in the first embodiment a locking mechanism is provided between the detector body and the detector base, and in the second embodiment a locking mechanism is provided between the head of the detector body and the main body case, it is also possible to provide both locking mechanisms in a single detector. This allows, for example, in a smoke detector with a point-emitting type operation indicator light, the orientation of the fins (smoke inlet) and the orientation of the operation indicator light to be set separately to desired angular directions.

In the first embodiment, the operating unit 33 is pushed toward the center of the sensor to elastically deform the support piece 32A, disengaging the serrated portion of the locking claw 32B from the serrated portion of the fixed-side claw 31 and releasing the lock. However, it is also possible to widen the opening through which the operating unit 33 passes in the outer wall 22 in the circumferential direction of the outer wall, and then slide the operating unit 33 in the circumferential direction to elastically deform the support piece 32A and release the lock, disengaging the serrated portion of the locking claw 32B from the serrated portion of the fixed-side claw 31. The "serrated portion" may have a shape (including serrations) that satisfies the locking mechanism by engagement, or may be processed to increase frictional resistance to prevent rotation.

Furthermore, in the second embodiment, it was explained that a spring member is inserted between the flange portion 12c of the head portion 12 and the flange portion 16a of the dark box 16, but when installed on the ceiling surface, the weight of the head portion 12 located at the bottom can maintain the engagement between the serrated portion 12d on the head portion 12 side and the serrated portion 11d on the outer cover 11 side, so the spring member may be omitted.
Furthermore, in the above embodiment, the present invention has been described as being applied to a smoke detector, but the present invention is not limited to smoke detectors and can be widely applied to detectors that have a unique structure (pillar) to protect the sensor or a point-light type indicator light.

10 Detector body 11 Outer cover (body case)
11A Opening 11d Jagged portion (notched portion)
12 Head portion 12a Lid portion 12b Fin (pillar)
12c: flange portion; 12d: jagged portion (notched portion)
13 Opening (smoke inlet)
14 Bottom plate 15 External terminal 16 Dark box 17 Light emitting member (indicator light)
18 Circuit board 19 Peripheral wall portion 20 Sensor base 21 Bottom wall 22 Outer wall 23 Inner wall 24 Connection terminal 25 Electric wire insertion hole 26 Screw hole 27 Terminal 30 Locking mechanism 31 Fixed side claw portion (serrated portion, notched portion)
32 Movable claw body (serrated portion, notched portion)
32A Support piece 32B Locking claw 33 Operation button

Claims (7)

A detector comprising: a main body incorporating a sensor and an electronic circuit for making a determination based on a signal from the sensor; and a base for fixing the main body to a mounting surface of a building, wherein the main body is provided with a head having a plurality of openings through which the sensor faces or an operation indicator light that is lit by the electronic circuit,
The base is
a first base member having a fixing portion for fixing to an outer wall and a mounting surface of a building;
a second base member having an inner wall having a smaller diameter than the outer wall and a coupling means for coupling with the main body portion,
The second base member is configured to be rotatable relative to the first base member, whereby the base and the main body portion are rotatably coupled together, and the main body portion and the head portion are configured to be changeable in angular positions in the circumferential direction relative to the base,
A sensor characterized in that a first locking mechanism is provided between the outer wall and the inner wall, which allows or prevents circumferential rotation of the second base member relative to the first base member . The first locking mechanism is
a notched portion formed along a circumferential direction on an outer surface of the inner wall;
a movable claw body having a claw that is inserted between the outer wall and the inner wall and that can be switched between an engaged state with the notched portion and a non-engaged state;
an operating portion that penetrates the outer wall and is partially exposed to the outside, and that changes the state of the movable claw;
2. The sensor according to claim 1, wherein the sensor is configured as follows: the movable claw body includes a support piece formed in an arc shape from a long plate-like elastic material, and a pair of claw bodies attached to both ends of the support piece and capable of engaging with the notched portion,
the operating portion is disposed such that an end portion opposite to a side that penetrates the outer wall and is exposed to the outside abuts against a center of a circumferentially outer surface of the support piece,
The sensor according to claim 2, characterized in that when the side that penetrates the outer wall and is exposed to the outside is pressed, the support piece elastically deforms and the pair of claws move away from the notch-shaped portion. A detector comprising: a main body incorporating a sensor and an electronic circuit for making a determination based on a signal from the sensor; and a base for fixing the main body to a mounting surface of a building, wherein the main body is provided with a head having a plurality of openings through which the sensor faces or an operation indicator light that is lit by the electronic circuit,
the main body includes a main body case that houses the sensor and the electronic circuit and has an opening at the center, and the head and the main body case are formed separately;
the head portion includes a plate-like lid portion, a plurality of pillar members each having one end connected to the lid portion and constituting the plurality of openings, and a flange portion having a diameter larger than a diameter of the openings and connecting the other ends of the plurality of pillar members to each other;
the head portion is rotatably attached to the main body case portion so that the plurality of pillar members are inserted into the openings, the lid portion is positioned outside the main body case portion, and the flange portion is positioned inside the main body case portion , thereby allowing the head portion to change its angular position in the circumferential direction relative to the base ;
A sensor characterized in that a second locking mechanism is provided between the flange portion and the edge of the opening, which allows or prevents circumferential rotation of the head portion relative to the main body case portion. The second locking mechanism is
a notched portion formed along a circumferential direction on a surface of the flange portion facing an edge portion of the opening;
a claw portion provided on an edge of the opening and capable of being converted between an engaged state with the notched portion and a non-engaged state;
5. The sensor according to claim 4, wherein the sensor is configured as follows: A detector base for fixing the detector to a mounting surface of an exterior structure,
a first base member having a fixing portion for fixing to an outer wall and a mounting surface of a building;
a second base member having an inner wall having a diameter smaller than that of the outer wall and a coupling means for coupling to a detector body having a built-in sensor;
a locking mechanism that allows or prevents rotation of the second base member relative to the first base member in a circumferential direction is provided between the outer wall and the inner wall;
The locking mechanism is
a notched portion formed along a circumferential direction on an outer surface of the inner wall;
a movable claw body having a claw that is inserted between the outer wall and the inner wall and that can be switched between an engaged state with the notched portion and a non-engaged state;
an operating portion that penetrates the outer wall and is partially exposed to the outside, and that changes the state of the movable claw;
A sensor base comprising: the movable claw body includes a support piece formed in an arc shape from a long plate-like elastic material, and a pair of claw bodies attached to both ends of the support piece and capable of engaging with the notched portion,
the operating portion is disposed such that an end portion opposite to a side that penetrates the outer wall and is exposed to the outside abuts against a center of a circumferentially outer surface of the support piece,
The sensor base of claim 6, characterized in that when the side that penetrates the outer wall and is exposed to the outside is pressed, the support piece elastically deforms and the pair of claws move away from the notch -shaped portion.