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

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

[0004] [Patent Document 1] JP 2000-235394 A Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of alarm bell, when used as the above-mentioned emergency bell, many units are often installed to ring simultaneously (individually or all at once). Therefore, it is preferable that the current consumption (drive current) of the motor of each alarm bell is small.

[0006] SUMMARY OF THE PRESENT INVETION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an alarm bell capable of reducing the current consumption of a motor. [Means for solving the problem]

[0007] This invention is an alarm bell comprising a striking rod, a gong struck by the striking rod, and a power transmission member which transmits the power of a motor to the striking rod via a cam, wherein the gong sounds when struck by the striking rod to sound an alarm, the power transmission member being connected at its base end to the cam and at its tip end to the striking rod, the cam having a cam surface portion which functions as a cam surface and a flange portion whose inner wall surface has an inclined surface which slopes towards 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 the one end side than at the other end side. Effect 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, so that 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 will occur not on the outer periphery of the inclined surface but on 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 provided. [Brief description of the drawings]

[0012] [Figure 1] 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. [Diagram 2]2A is an enlarged side view of the example of the striking rod of the alarm bell of the same embodiment as in FIG. 1, FIG. 2B is an enlarged side view of another example, and FIG. 2C is an enlarged side view of yet another example. [Diagram 3] 4A is a perspective view of the cam of the alarm bell of the above-mentioned embodiment, with the power transmission member connected thereto, and FIG. [Figure 4] FIG. 1 shows the cam alone of the alarm bell, where (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 AA in (a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0014] [Basic configuration] As shown in Fig. 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 striking of the striking rod 3 will cause the gong 2 to ring, sounding an alarm. The striking mechanism parts such as the striking rod 3 and the motor 4 are provided on the inside surface of the gong 2.

[0015] [Battle stick] Specifically, the striking rod 3 reciprocates back and forth in the lengthwise direction by 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.

[0016] ·slit 1 and 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.

[0017] In the alarm bell 1, the provision of the 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.

[0018] -Specific examples of slits Specifically, in the illustrated example, the slit 3c is recessed into the side of the batting bar 3, and a long, 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.

[0019] Example of slit change The shape of the slit 3c can be changed 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.

[0020] ·hole As a means for increasing the repulsive force of the batting stick 3 when hitting, a hole may be used instead of or in addition to a groove such as the slits 3c and 3c' described above. Figure 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 that penetrates the side of the batting stick 3. There is only 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 more than one, or it may be another polygonal shape (including one with rounded corners), circular, or elliptical. Furthermore, the through hole may be formed in a rectangular shape (including one with rounded corners), or in a rectangular shape (including one with rounded corners). Instead of being recessed, they may be formed as blind holes.

[0021] [cam] As shown in Fig. 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.

[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 thereon to provide spring properties (see FIGS. 1 and 3).

[0024] ·Slope 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, by providing the inclined surfaces 5c, 5c, even if the contact portion with the connecting 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 on a portion close to the cam surface 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.

[0026] Incidentally, 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 portion 5a rotates at a larger rotation radius 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 since the connecting portion 6a is usually 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 one end 5aa side with a larger axial width than the other end 5ab side (see FIG. 4(d)). As a result, the power transmission part 6 is in contact only with the 5ab side, which is usually the small diameter side, and the current consumption of the motor 4 can be reduced.

[0029] [Example of changing the configuration] 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 in terms of increasing the repulsive force of the batting bar 3 when hitting, it is more advantageous to make the depth greater than the center line of the batting bar 3 in the longitudinal direction, as described above.

[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, not at the center of gravity of the cam 5. Also, the shape of the cam 5 may be an ellipse instead of 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. [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 section 6a, 6b: Connection section

Claims

1. An alarm bell comprising: a striking rod; a gong struck by the striking rod; and a power transmission member that transmits power of a motor to the striking rod via a cam, the gong sounding when struck by the striking rod to sound an alarm, The power transmission member has a base end connected to the cam and a tip end 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 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 said 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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