JP7570869B2 - Alarm bell - Google Patents

Description

This invention relates to an alarm bell that sounds a gong when struck to sound an alarm.

The alarm bell is equipped with a gong that produces a bell sound when struck, a striking rod that strikes the gong, a motor that drives the striking rod, and a housing that houses the motor, and is used to sound an alarm by ringing the gong and producing a bell sound in the event of an emergency such as a fire (see, for example, Patent Document 1).

The main examples of its use are the local sound devices of automatic fire alarm systems and the emergency bells of emergency alarm systems (hereafter simply referred to as "emergency bells").

JP 2000-235394 A

When used as emergency bells, this type of alarm bell is often installed in large numbers to ring simultaneously (individually or all at once). For this reason, it is preferable for the motor current consumption (drive current) of each alarm bell to be small.

In view of the above, the objective of this invention is to provide an alarm bell that can reduce the current consumption of the motor.

This invention is an alarm bell which comprises a striking stick and a gong which is struck by the striking stick, and which sounds the gong when struck with the striking stick to sound an alarm, wherein the striking stick has a slit or hole formed in a position close to the striking part which strikes the gong, the slit or hole being recessed or drilled into the side of the striking stick and having a depth which exceeds the centre line of the striking stick in the longitudinal direction .

In this invention, the hitting machine may further include a power transmission member that transmits the power of the motor to the hitting rod via a cam, the power transmission member being connected at its base end to the cam and at its tip end to the hitting rod, the cam having a cam surface portion that functions as a cam surface by wrapping the connecting portion at the base end of the power transmission member around it, and a flange portion having an inclined surface that inclines toward the cam surface portion on its inner wall surface. The flange portion may be provided at both ends of the cam surface portion in the axial direction. The cam surface portion may be provided in such a manner that one end side in the length direction rotates with a larger turning radius than the other end side. The cam surface portion may have a larger axial width at the one end side than the other end side.

In this invention, a slit or hole is provided in the striking portion of the striking rod, which increases the repulsive force of the striking rod when it strikes the gong. This reduces the load on the motor when the striking rod is pulled back, and reduces the current consumption of the motor.

Therefore, this invention provides an alarm bell that can reduce the current consumption of the motor.

FIG. 2 is a rear view showing an example of an embodiment of the alarm bell of the present invention, showing the striking mechanism part, such as the striking rod and motor, which are provided on the rear side of the gong, with the back cover of the housing open. 2A is an enlarged side view of the example of the striking rod of the alarm bell of the same embodiment as that of FIG. 1, FIG. 2B is an enlarged side view of another example, and FIG. 2C is an enlarged side view of yet another example. 3A is a perspective view of the cam of the alarm bell of the above embodiment, in a state in which a power transmission member is connected, and FIG. (a) is a front view (one side of the flange), (b) is a left side view, (c) is a right side view, (d) is a top view, and (e) is a cross-sectional view taken along line A-A in (a) of the cam of the above-mentioned alarm bell.

An example of an embodiment of the alarm bell of this invention will be described as alarm bell 1 with reference to Figures 1 to 4. Note that alarm bell 1 can be used, for example, as a district sounding device in an automatic fire alarm system or an emergency bell in a sounding device in an emergency alarm system.

[Basic configuration]
1, the alarm bell 1 comprises a gong 2, a striking rod 3 that strikes the gong 2, a motor 4 that drives the striking rod 3, and a power transmission member 6 that transmits the power of the motor 4 to the striking rod 3 via a cam 5. In the event of an emergency such as a fire, the gong 2 sounds when struck by the striking rod 3, thereby issuing an alarm. The striking mechanism, including the striking rod 3 and the motor 4, is provided on the inside surface of the gong 2.

[Batting]
Specifically, the striking rod 3 reciprocates back and forth in the lengthwise direction due to the power of the motor 4 transmitted via a cam 5 and a power transmission member, and when it moves forward, it strikes the gong 2 with the spherical crown-shaped striking part 3a provided at the tip.

Slit As shown in FIG. 1 and FIG. 2(a), the striking rod 3 is provided with a slit 3c at a position adjacent to the striking portion 3a that strikes the gong 2.

In the alarm bell 1, the provision of this slit 3c makes it possible to increase the repulsive force of the striking rod 3 when it strikes the gong 2. This reduces the load on the motor 4 when the striking rod 3 is pulled back, and reduces the current consumption of the motor 4.

Specific example of slit Specifically, in the illustrated example, the slit 3c is recessed into the side of the batting bar 3, and a long and narrow groove is formed in the transverse direction of the batting bar 3. Furthermore, the depth of the groove exceeds the center line of the batting bar 3 in the longitudinal direction.

-Examples of slit modification The shape of the slit 3c can be modified as appropriate as long as it can increase the repulsive force during hitting. For example, in the case of the slit 3c, one groove is provided, but multiple grooves may be provided. FIG. 2(b) shows an example of multiple grooves. In the figure, the slits 3c', 3c' have two grooves. Both of the two grooves are recessed into the side of the batter 3 and formed in the transverse direction of the batter 3, like the groove of the slit 3c, but are arranged in two stages, front and rear, and open in opposite directions. In the case where multiple grooves are arranged in stages, the opening direction of each groove may be alternately opened in opposite directions as described above, or may be opened in the same direction.

Holes As a means for increasing the repulsive force of the batting bar 3 during hitting, a hole may be used instead of or in addition to a groove such as the slit 3c or 3c'. FIG. 2(c) shows an example of a hole being used instead of a groove. In the figure, the hole 3c'' is formed as a through hole penetrating the side of the batting bar 3. There is only one hole, and its shape is a square (including one with rounded corners). The number and shape of the hole 3c'' can be changed as appropriate. For example, there may be multiple holes, or the hole may be another polygonal shape (including one with rounded corners), a circular shape, or an elliptical shape. Furthermore, instead of being a through hole, the hole may be a recessed hole, and may be formed as a non-through hole.

[cam]
1, the cam 5 is fixed to the drive shaft 4a of the motor 4 and rotates together with the drive shaft 4a. A connection part 6a on the base end side of a power transmission member 6, whose connection part 6b on the tip end side is connected to the striking rod 3, is connected to the cam 5, and the power of the rotational motion of the motor 4 is transmitted to the striking rod 3 as a reciprocating motion power via the cam 5 and the power transmission member 6. This causes the striking rod 3 to reciprocate back and forth in the length direction.

Specifically, as shown in Figures 3 and 4, the cam 5 has a cam surface portion 5a to which the connecting portion 6a of the power transmission member 6 is wound and connected, which functions as a cam surface, and flange portions 5b, 5b provided on both axial sides of the cam surface portion 5a.

In the illustrated example, the power transmission member 6 is made of a linear member and has a bent portion in the middle to give it spring properties (see Figures 1 and 3).

Inclined Surfaces The flange portions 5b, 5b of the cam 5 are provided on their inner wall surfaces with inclined surfaces 5c, 5c that are inclined toward the cam surface portion 5a.

In the alarm bell 1, the inclined surfaces 5c, 5c are provided, so that even if the contact portion with the connection portion 6a of the power transmission member 6 comes into contact with the inclined surface when the cam 5 rotates, the contact occurs not on the outer periphery of the inclined surface but in a portion close to the cam surface portion 5a, thereby reducing the friction torque generated by the contact. This reduces the load on the motor 4, and the current consumption of the motor 4 can be reduced.

It is preferable that the inclined surfaces 5c, 5c are provided on both sides of the flange portions 5b, 5b, but they may be provided on only one side.

- Radius of rotation In the illustrated example, the cam 5 is disposed so that the cam surface portion 5a rotates at a larger radius of rotation at one end 5aa side in the length direction than at the other end 5ab side (see Fig. 3(a) and Fig. 4(d)). This provides power for reciprocating motion, but since the connecting portion 6a is usually always in contact with the one end 5ab side, the rotation torque load can be reduced. This also reduces the load on the motor 4, and the current consumption of the motor 4 can be reduced.

Furthermore, in the illustrated example, the cam 5 has a larger axial width at one end 5aa than at the other end 5ab (see FIG. 4(d)). As a result, the power transmission part 6 is in contact only with the 5ab side, which is normally the smaller diameter side, and the current consumption of the motor 4 can be reduced.

[Example of configuration change]
In the alarm bell 1, for example, the configuration can be changed as follows.

The depth of the slits 3c and 3c' may be shallower. However, in terms of increasing the repulsive force of the bat 3 when hitting, it is more advantageous to make the depth greater than the center line of the bat 3 in the longitudinal direction, as mentioned above.

The angle of inclination of the inclined surfaces 5c, 5c can be changed as appropriate, and may be steeper or gentler than that shown in the figure.

The same effect can also be achieved by making the following changes:
The inclination shape of the cam 5 may be an arcuate inclination instead of a linear inclination.
The central axis of the cam 5 may be located at an eccentric position, not at the center of gravity of the cam 5. The shape of the cam 5 may be an ellipse, not a circle, a rounded rectangle, or a rounded triangle.
The thickness of the flange portion 5b of the cam 5 may vary depending on the position of the cam. For example, in order to equalize the rotation balance of the cam 5, the end 5aa side may be made thin and the end 5ab side may be made thick.
The cam surface portion 5a may have a shape having a plurality of ends 5aa from the center to the distal end side. In this case, the cross-sectional shape of the cam surface portion 5a may be a rounded triangle or a rounded rectangle. For example, when the cross-sectional shape is a rounded triangle, the power transmission member 6 can reciprocate three times during one rotation of the cam 5.

1: Alarm bell 2: Gong 3: Batter 3a: Striking part 3c, 3c': Slit 3c'': Hole 4: Motor 4a: Drive shaft 5: Cam 5a: Cam surface 5aa, 5ab: End 5b: Flange 5c: Inclined surface 6: Power transmission part 6a, 6b: Connection part

Claims (2)

An alarm bell comprising a striking stick and a gong struck by the striking stick, the gong ringing when struck by the striking stick to sound an alarm,
The striking rod has a slit or a hole at a position adjacent to a striking part that strikes the gong ,
An alarm bell characterized in that the slit or hole is recessed or penetrated into the side of the striking rod and has a depth that exceeds the center line of the striking rod in the longitudinal direction . The driving force of the motor is transmitted to the striking rod via a cam.
The alarm bell described in claim 1, characterized in that the power transmission member is connected to the cam at its base end and to the striking rod at its tip end, and the cam has a cam surface portion that functions as a cam surface by wrapping the connection portion of the base end side of the power transmission member around it, and a flange portion whose inner wall surface has an inclined surface that slopes toward the cam surface portion .

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