Alarm bell

Abstract

To provide an alarm bell capable of reducing electric current consumption of a motor.SOLUTION: An alarm bell includes: an alarm bell hitting rod; a gong hit by the hitting rod; and a power transmission member 6 for transmitting the power of a motor to the hitting rod via a cam 5. The alarm bell issues an alarm by the gong making a sound by the hitting of the hitting rod. In the power transmission member 6, a connection portion 6a on a base end side is connected to the cam 5, and a connection portion 6b on a tip side is connected to the hitting rod. The cam 5 includes: a cam surface part 5a around which the connection portion 6a on the base end side of the power transmission member 6 is wound and which functions as a cam surface; and a flange part 5b in which an inclined surface 5c inclined toward the cam surface part 5a is provided on an inner wall surface.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to an alarm bell that sounds a gong when struck to give an alarm. [Background technology]

[0002] An alarm bell comprises a gong that produces a bell sound when struck, a striker that strikes the gong, a motor that drives the striker, and a housing that houses the motor. In the event of an emergency such as a fire, the gong sounds, producing a bell sound and issuing an alarm (see, for example, Patent Document 1).

[0003] The main examples of use are the local sounding devices of automatic fire alarm systems and the emergency bells of emergency alarm systems (hereinafter simply referred to as "emergency bells"), etc. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-235394 Summary of the Invention [Problem to be solved by the invention]

[0005] When used as emergency alarms, these types of alarms are often installed in large numbers to ring simultaneously (either in separate rings or all at once). Therefore, it is preferable that the current consumption (drive current) of each alarm bell motor is small.

[0006] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an alarm bell that can reduce the current consumption of the motor. [Means for solving the problem]

[0007] This invention is an alarm bell comprising a striker, a gong that is struck by the striker, and a power transmission member that transmits the power of a motor to the striker via a cam, and in which the gong sounds when struck by the striker, thereby sounding an alarm, wherein the power transmission member is connected at its base end to the cam and at its tip end to the striker, and the cam has a cam surface portion that functions as a cam surface, around which the connecting portion at the base end of the power transmission member is wound, and a flange portion whose inner wall surface has an inclined surface that slopes toward the cam surface portion.

[0008] In the present invention, the cam surface portion may rotate with a larger radius of rotation at one end in the length direction than at the other end.

[0009] In the present invention, the cam surface portion may have a larger axial width at one end than at the other end. [Effects of the Invention]

[0010] In this invention, the inner wall surface of the flange of the cam is provided with an inclined surface that slopes toward the cam surface. Therefore, even if the contact portion with the connecting portion of the power transmission member comes into contact with the inclined surface when the cam rotates, the contact occurs not on the outer periphery of the inclined surface but in a portion close to the cam surface, thereby reducing the friction torque generated by the contact, thereby reducing the load on the motor and the current consumption of the motor.

[0011] Therefore, according to the present invention, an alarm bell capable of reducing the current consumption of the motor is obtained. [Brief explanation of the drawings]

[0012] [Figure 1] This shows an example of an embodiment of the alarm bell of the present invention, and is a rear view showing the striking mechanism part, such as the striking rod and motor, which are provided on the back side of the gong, with the back cover of the housing open. [Figure 2]2A is an enlarged side view of the example of the striking rod of the alarm bell of the same as above, FIG. 1; FIG. 2B is an enlarged side view of another example; and FIG. 2C is an enlarged side view of yet another example. [Figure 3] 1A is a perspective view of the cam of the alarm bell of the same embodiment, in a state in which a power transmission member is connected, and FIG. 1B is a bottom view thereof. [Figure 4] (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 along line AA in (a) of the cam alone of the alarm bell. DETAILED DESCRIPTION OF THE INVENTION

[0013] An example of an embodiment of the alarm bell of the present invention will be described as an alarm bell 1 with reference to Figures 1 to 4. The alarm bell 1 can be used, for example, as a district sounding device in an automatic fire alarm system or as an emergency bell in a sounding device in an emergency alarm system.

[0014] [Basic configuration] As shown in Figure 1, alarm bell 1 comprises a gong 2, a striking rod 3 that strikes gong 2, a motor 4 that drives striking rod 3, and a power transmission member 6 that transmits the power of motor 4 to striking rod 3 via cam 5. In the event of an emergency such as a fire, alarm bell 1 is used to sound the gong 2 by striking striking rod 3. The striking mechanism, including striking rod 3 and motor 4, is located on the inside surface of gong 2.

[0015] [Battle stick] Specifically, the striking rod 3 moves back and forth along its length using 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 at the tip.

[0016] ·slit 1 and 2(a), the striking rod 3 is provided with a slit 3c at a position close to the striking part 3a that strikes the gong 2.

[0017] In the alarm bell 1, the provision of this slit 3c increases the repulsive force of the hammer 3 when it strikes the gong 2. This reduces the load on the motor 4 when the hammer 3 is pulled back, and reduces the current consumption of the motor 4.

[0018] Specific examples of slits Specifically, in the illustrated example, the slit 3c is recessed into the side of the batting rod 3, and forms a long, narrow groove in the transverse direction of the batting rod 3. Furthermore, the depth of the groove exceeds the center line of the batting rod 3 in the longitudinal direction.

[0019] Example of changing the slit The shape of slit 3c can be modified as needed as long as it increases the repulsive force during impact. For example, slit 3c has one groove, but multiple grooves are also acceptable. Figure 2(b) shows an example of multiple grooves. In the figure, slits 3c', 3c' each have two grooves. Like slit 3c, both grooves are recessed into the side of batting rod 3 and extend transversely across batting rod 3. However, they are arranged in two rows, front and rear, and open in opposite directions. When multiple grooves are arranged in rows, the openings of each groove may alternately open in opposite directions, as described above, or they may open in the same direction.

[0020] ·hole As a means for increasing the repulsive force of the batting rod 3 when hitting, holes may be used instead of or in addition to grooves such as the slits 3c and 3c'. Figure 2(c) shows an example of a case where holes are used instead of grooves. In the figure, the hole 3c'' is formed as a through-hole that penetrates the side of the batting rod 3. There is one hole, and its shape is rectangular (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), circular, or elliptical. Furthermore, the through-hole Instead of being formed as a through hole, it may be formed as a recessed hole and not as a through hole.

[0021] [cam] As shown in Figure 1, the cam 5 is fixed to the drive shaft 4a of the motor 4 and rotates together with the drive shaft 4a. The cam 5 is connected to a base end connection part 6a of a power transmission member 6, whose tip end connection part 6b is connected to the striking rod 3, and the power of the rotational motion of the motor 4 is transmitted to the striking rod 3 as power for reciprocating motion 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.

[0022] Specifically, as shown in Figures 3 and 4, the cam 5 has a cam surface portion 5a to which the connection portion 6a of the power transmission member 6 is wound and connected, and which functions as a cam surface, and flange portions 5b, 5b provided on both axial sides of the cam surface portion 5a.

[0023] In the illustrated example, the power transmission member 6 is made of a linear member and has a bent portion provided midway to provide spring properties (see FIGS. 1 and 3).

[0024] ·Slope surface 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.

[0025] In the alarm bell 1, the provision of the inclined surfaces 5c, 5c means that even if the contact portion between the cam 5 and the connecting portion 6a of the power transmission member 6 comes into contact with the inclined surface as the cam 5 rotates, the contact occurs at a portion close to the cam surface 5a, not at the outer periphery of the inclined surface, 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.

[0026] 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.

[0027] Turning radius In the illustrated example, the cam 5 is disposed such that the cam surface 5a rotates at a larger radius of rotation at one end 5aa in the longitudinal direction than at the other end 5ab (see FIGS. 3(a) and 4(d)). This provides power for the reciprocating motion, but because the connecting portion 6a is normally always in contact with the one end 5ab, the rotational 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.

[0028] 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.

[0029] [Configuration change example] In the alarm bell 1, for example, the configuration can be changed as follows.

[0030] The depth of the slits 3c, 3c' may be shallower, but as mentioned above, it is more advantageous to make the depth of the slits 3c, 3c' so that they extend beyond the center line of the length of the batting rod 3 in order to increase the repulsive force of the batting rod 3 when hitting the ball.

[0031] 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 drawing.

[0032] The same effect can also be achieved by making the following changes: The inclination shape of the cam 5 may be an arc-shaped inclination instead of a linear inclination. The central axis of the cam 5 may be located at an eccentric position rather than at the center of gravity of the cam 5. Also, the shape of the cam 5 may be an ellipse instead of a circle, or 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 even out the rotation balance of the cam 5, the end 5aa side may be made thinner and the end 5ab side may be made thicker. The cam surface portion 5a may have a shape having multiple end portions 5aa extending from the center toward the distal end. In this case, the cross-sectional shape of the cam surface portion 5a may be a rounded triangle or a rounded rectangle. For example, if the cross-sectional shape is a rounded triangle, the power transmission member 6 can reciprocate three times during one rotation of the cam 5. [Explanation of symbols]

[0033] 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 portion 5aa, 5ab: End portion 5b: Flange portion 5c: Inclined surface 6: Power transmission part 6a, 6b: Connection part

Claims

1. An alarm bell comprising: a hammer; a gong struck by the hammer; and a power transmission member that transmits power of a motor to the hammer via a cam, wherein the gong sounds when struck by the hammer to issue an alarm, a base end side of the power transmission member is connected to the cam, and a tip end side of the power transmission member is connected to the striking rod; An alarm bell characterized in that the cam has a cam surface portion around which the connection portion on the base end side of the power transmission member is wound and which functions as a cam surface, and a flange portion whose inner wall surface has an inclined surface that slopes toward the cam surface portion.

2. 2. The alarm bell according to claim 1, wherein the cam surface portion rotates with a larger radius of rotation at one end in the length direction than at the other end.

3. 3. The alarm bell according to claim 2, wherein the cam surface portion has a larger axial width at the one end side than at the other end side.

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