JPH09230855A - Music box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the music box which prevents a worm from moving in its thrust direction and eliminates trouble due to unevenness of the rotation of a drum. SOLUTION: Of this music box, a speed control means which controls the rotating speed of the drum that is driven and rotated by a spiral 2 supported on a frame 1 to play music by flicking vibration valves 5a of a diaphragm 5 consists of a speed increasing gear train 6 which has two stages of worms 15 and 17 and a braking means 7 provided atop of the speed increasing gear train. Then a position holding means 44 which stops at least the 1st worm 15 positioned on a driving source side between the two worms 15 and 17 from moving axially is arranged on the frame 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a music box having a plurality of worms in a speed increasing train wheel which constitutes a speed controlling means of a drum.

[0002]

2. Description of the Related Art A music box which plays a tune by playing a vibration valve with a pin implanted in a drum transmits a driving force from a rotary drive source to a speed governing means called a governor via the drum to rotate the drum. Is kept constant. The governor is for stabilizing the rotation of the drum, and includes a speed increasing train wheel and braking means. Some speed increasing trains are provided with a plurality of worms and worm wheels in the train so that a large speed increasing ratio can be obtained. For example, when worms are used in the middle and final stages of the speed increasing train wheel, a braking member is provided in the worm used in the final stage to rotate at high speed, and frictional braking at that time stabilizes the drum rotation. ing.

[0003]

In the music box, the worm is supported with a play in the axial direction generally called thrust play in consideration of the assembling property of the worm and the tolerance of parts. However, this worm is moved by the biasing force that is generated in the axial direction when it rotates at high speed in response to rotation from the worm wheel. The direction of the generated biasing force differs depending on the input direction to the worm, that is, the rotation direction of the worm. For example, when the input to the worm is transmitted from the drive source side, the input tangential force of the shaft moves, the input from the drive source side weakens, and the inertia force of the braking means rotating at high speed increases. Move in the direction opposite to the input tangential force direction.

When the moving direction of the worm changes depending on the direction of the biasing force thus generated, when the direction of the biasing force is switched, a large play occurs between the worm and the worm wheel, and the braking means does not act. In some cases, the drive source becomes free and the drum rotates rapidly. Such uneven rotation of the drum is not good for playing a song, and causes problems such as deterioration in sound quality and difficulty in listening to the song. In particular, when a plurality of worms are used in the speed increasing train, the speed increasing ratio of the speed increasing means becomes large, so the worm provided in the middle of the same train does not move in the axial direction due to the biasing force. This will greatly affect the meshing condition with the wheel.

There is no problem if the thrust play of each worm can be reduced to 0, but it is difficult in reality due to problems such as component tolerances. Even if it is set to 0, the support portion that supports the worm by the biasing force applied to the worm is made of material. In some cases, the end of the worm is worn in the direction in which the biasing force is applied, which causes thrust play. It is an object of the present invention to provide a music box that prevents the worm from moving in the thrust direction and eliminates the problems caused by uneven rotation of the drum.

[0006]

In order to achieve the above object, according to the present invention, the rotational speed of a drum which plays a vibration by vibrating a vibration valve of a diaphragm by a drum which is rotationally driven by a drive source supported on a frame. The speed control means for speed control is 2
A speed increasing wheel train having a two-stage worm and a braking means provided at the end of the speed increasing wheel train, and the first worm located at least on the drive source side of the two-stage worms moves in the thrust direction. Position holding means for preventing the above is arranged on the frame.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In a music box according to the present invention,
A vibrating plate having a vibrating valve, a drum for playing a song by playing the vibrating plate, a drive source for rotationally driving the drum, and 2
The speed increasing wheel train having a worm of steps and the braking means provided at the final stage of the speed increasing wheel train support speed adjusting means for adjusting the rotational speed of the drum on the frame.
Then, on this frame, there is arranged a position holding means for preventing the first worm, which is located at least on the drive source side, of the two-stage worms from moving in the thrust direction.

When the position holding means is provided so as to bias the first worm in the direction of the biasing force generated when the first worm is driven by the driving source, the first worm is always attached in the direction of the biasing force. The movement of the first worm is stabilized by being biased. Further, even if a shaft portion is provided on the first worm, a bearing is formed on the frame to support the first worm, and a position holding means composed of an elastic piece is brought into contact with the end portion of the shaft to urge it. Of course, as the elastic piece, a tongue piece integrally formed with a barrel box surrounding the drive source may be used. Further, when the mainspring is used as the drive source and the winding shaft of the mainspring is arranged at approximately the center of the frame, the balance of the music box is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings. In the music box shown in FIGS. 1 and 2, a mainspring 2 and a winding shaft (hereinafter referred to as a “winding shaft”) 3 are arranged substantially at the center of a frame 1, and drums 4 and a plurality of combs are provided at four corners around the frame 1. A vibrating plate 5 having a tooth-shaped vibrating valve 5a, a speed increasing wheel train 6 serving as speed adjusting means, and a braking means 7 are arranged. The mainspring 2, the winding shaft 3, the speed increasing train wheel 6 and the like are
It is substantially covered by a case 8 that is attached to the frame 1 and serves as a barrel.

The operation of the entire music box will be briefly described. The mainspring 2 wound around the winding shaft 3 rotates the winding shaft 3 by releasing the stored force, and the first gear 12 integrated with the winding shaft 3 which is a part of the speed increasing train 6 rotates to rotate the drum. Four
The drum 4 is rotationally driven through the pinion 10 integrated with the drum 4. The rotation of the drum 4 causes the vibrating valve 5a to play a tune. Further, the rotation of the first gear 12 is transmitted to the braking means 7 after being accelerated through the speed increasing train wheel 6. Braking means 7
With this rotation, frictional braking is caused by this rotation, and the speed of the drum 4 is adjusted so that the rotation of the drum 4 does not rise excessively to stabilize the rotation of the drum 4.

The metal frame 1 made of zinc metal or the like has mounting holes 40, 41, 42, 4 formed in the case 8 in the frame 1.
Pins 40a, 41a, 42 for crimping to be inserted into
A and 43a are formed so as to project upward, and after inserting each pin into each mounting hole, the head of the pin is crushed to fix the case 8 to the frame 1. Here, the case 8 and the frame 1 are integrated by caulking each pin, but screw holes may be used instead of each pin by providing screw holes.

The case 8 is made of synthetic resin, and has a main housing 61 for housing the mainspring 2, a gear housing 62 for surrounding the speed increasing train 6, and a drum 4 between the frame 1.
The drum bearing portion 9 for rotatably supporting the rotating body 70 and the rotating body 70 of the braking means 7 are slidably contacted with each other to integrally form a fixed wall portion 60 for braking the speed increasing gear train 6. It should be noted that the main housing portion 61, the gear housing portion 62, the drum bearing portion 9, the fixed wall portion 60, and the like may be molded separately or partially separately to be integrated on the frame 1.

The drum 4 is arranged at one corner of the frame 1 so as to stand upright with respect to the frame 1. The drum 4 is rotated around the vertical center of rotation by the frame 1 and a drum bearing portion 9 projecting from the case 8 in parallel therewith. It is rotatably supported by. As shown in FIG. 3, the drum 4 has a cylindrical portion 4a in which a pin 4d for flipping the vibration valve 5a is planted on the peripheral surface, and an upper end plate 4b that closes one end of the cylindrical portion 4a to form a bearing portion. The lower end plate 4c integrally includes a pinion 10 that meshes with a first gear 12 provided on the winding shaft 3 and an output gear 11 that takes out a driving force to a movable member (not shown).

In the drum 4, the upper end plate 4b and the lower end plate 4c are directly press-fitted to each other to integrate the entire drum. That is, from the upper end plate 4b and the lower end plate 4c, sleeves 4f and 4g for press-fitting inward are respectively provided.
Are projected by integral molding, and the sleeve portions 4f and 4g are press-fitted by sandwiching the tubular portion 4a between the both end plates 4b and 4c, whereby the both end plates 4b and 4c and the tubular portion 4a are combined and integrated. ing. As a result, it is possible to prevent the lower end plate 4c from idling at the time of playing, and the drum rigidity is increased and the sound is improved.

In this drum 4, a shaft portion 4e integrally formed with a lower end plate 4c is supported by a drum shaft support hole 18 formed in the frame 1, and an upper end plate 4b is downward from a drum bearing portion 9 integral with a case 8. It is rotatably supported by being fitted with the shaft portion 19 protruding inward. The drum shaft support hole 18 has a tapered hole 18A at the opening on the lower end plate 4c side of the drum 4, and a tapered shoulder portion 18 formed on the shaft portion 4e of the lower end plate 4c.
It is provided to receive and support B. A recess 20 for accommodating the pinion 10 portion is formed in the frame 1 around the drum shaft support hole 18 so as to be one step lower than the frame upper surface 1a, and has a structure for suppressing the height in the vicinity of the drum.

Between the drum bearing portion 9 and the upper end plate 4b,
A spring member 22 that urges the drum 4 in the axial direction is interposed, presses the drum 4 against the tapered hole 18A of the frame 1, and imparts a constant braking force to the drum 4. The spring member 22 has the cylindrical shaft portion 19 formed on the inner side of the drum bearing portion 9 and the upper end plate 4 of the drum 4.
The drum 4 is rotatably supported by being inserted into the hole 21 of b. Here, a disc spring is used as the spring member 22, but the spring member 22 is not limited to this. The frame 1'in the vicinity of the output gear 11 is formed to be slightly larger than the outer diameter of the gear 11 to prevent the output gear 11 from being damaged when the music box falls.

The winding shaft 3 of the mainspring 2 penetrates through the frame 1 at approximately the center of the frame 1 and the mainspring housing portion 61.
It is arranged inside and is rotatably supported by the case 8 and the frame 1. More specifically, as shown in FIG. 4B, the upper end 3a of the winding shaft 3 is attached to a boss portion 46 provided eccentrically from the central portion of the mainspring housing portion 61 so as to be substantially at the center of the frame 1. Perforated bearing part 4
7, the lower end 3b penetrates the bearing portion 23 formed in the frame 1 and projects to the outside of the frame 1. As shown in FIG. 5, a threaded portion 3c is provided on the lower end 3b of the winding shaft 3 protruding outside the frame 1, and a winding key (not shown) or a base (not shown) that is a substitute thereof is usually attached.

As shown in FIG. 4B, a mainspring stop pin 29 for locking the inner end 2a of the mainspring 2 is provided at the center of the winding shaft 3 so as to project in the radial direction. A hole 2c is formed at the inner end 2a of the mainspring 2, and the mainspring 2 is wound into the mainspring housing 61 by hooking a spring stop pin 29 in the hole 2c and rotating the winding shaft 3 in the winding direction.

Like the pinion 10 of the drum 4, the No. 1 gear 12 connected to the winding shaft 3 is housed in a recess which is lower than any other portion of the frame 1 and has a bearing hole 2 in the frame 1.
It is rotatably supported by a convex portion 48 formed around 3. The mainspring 2 is arranged above this.

The winding shaft 3 and the first gear 12 are the ratchet 2
It is connected via 4 so that rotation is transmitted only in one direction. For example, as shown in FIG. 4A, the ratchet 24 has a substantially S-shaped planar shape, and the annular portion 2 at the center portion.
4a is fitted so as to engage with the winding shaft 3 only in the rotational direction. Here, the inner peripheral surface of the annular portion 24a has 90
The recesses 25 are formed at every 90 ° so as to engage with the protrusions 26 formed at every 90 ° on the outer peripheral surface of the winding shaft 3 only in the rotational direction, and the winding shaft 3 and the ratchet 24 are provided so as to rotate integrally. There is. The arcuate elastic arms 24b of the ratchet 24 are formed symmetrically at opposite positions, and the tip end thereof has the first gear 1
A claw portion 27 that engages with the claw portion 28 formed on the inner peripheral surface of the second boss portion in only one direction is provided. The claw portion 28 has a tooth surface in the normal direction that engages with the claw portion 27 in the counterclockwise rotation direction of the ratchet 24, and in the clockwise rotation direction of the ratchet 24, the elastic arm 24b is deformed inward to deform the claw portion. An inclined surface is provided to prevent 27 from passing over the pawl portion 28 and transmitting rotation.

The outer end 2b of the mainspring 2 projects to the outside of the mainspring housing portion 61 as shown in FIG. 2, and a constricted portion 49 called necking is formed as shown in FIG. The constricted portion 49 is hooked and fixed to an engaging portion 50 formed by the case 8 and the frame 1. The engaging portion 50 is composed of a lateral rib 51 integrally formed on the upper surface 1a of the frame 1 and a protrusion 52 formed on the back surface 8a of the case 8, and a constricted portion 49 is formed between them.
Are hooked.

As shown in FIGS. 1, 2 and 5, the diaphragm 5 is fastened to the side wall 57a of the pedestal 57 which is vertically projected from the upper surface 1a of the frame 1 by a fastening member such as a screw 58. Like the drum 4, it is arranged vertically and laterally with respect to the frame 1. Therefore, the frame 1 of the diaphragm 5
The flat area occupied by is approximately equal to the plate thickness.
The vibrating plate 5 is fixed to the pedestal 57, and its tip is engaged with the pin 4d of the drum 4 and is arranged so as to substantially overlap with the rotation center axis of the drum 4. The vibration valve 5a is repelled at a certain portion. The vibrating plate 5 is fixed to the pedestal 57 with its treble side closer to the frame 1, and accordingly, the drum 4 also has its treble side close to the frame 1 and its bass side to the drum bearing. It is arranged so as to be on the side of the portion 9.

The pedestal 57 is integrally molded with the frame 1 by casting or the like to form a cantilever support structure. The pedestal 57 is formed with a barrier 55 that abuts against the tip 2b1 of the outer end 2b of the mainspring 2 in a direction orthogonal to the side plate 57a so as to regulate the movement of the outer end 2b. This barrier 55
It is also connected to the frame 1 to increase the thickness of the lower portion of the pedestal 57 to increase the rigidity of the pedestal 57. Barrier 55
An opening 56 is formed between the case 8 and the case 8.
As shown in FIG. 2, the opening 56 communicates with the mainspring housing portion 61 and serves as an insertion port for inserting the mainspring 2 into the mainspring housing portion 61.

As shown in FIGS. 2 and 6, the accelerating train wheel 6, which is a characteristic part of the present invention, includes two worms (hereinafter referred to as “third worm 15” and “fourth worm 17”) orthogonal to each other. Is described therein, and these are arranged around the mainspring 2 as close as possible and a high speed increasing ratio is obtained.

The speed increasing train wheel 6 is a second gear 13 which meshes with a first gear 12 which is integral with a winding shaft 3 which is rotated by releasing a mainspring 2 which is a drive source, and a second worm wheel which is coaxial with the gear 13. No. 3 worm 15 meshing with No. 14 and No. 3 worm wheel 1 arranged coaxially with No. 3 worm 15
It is composed of a fourth worm 17 that meshes with the No. 6 worm. 1
The number gear 12 also meshes with a pinion 10 provided integrally with the drum 4. So in this music box,
The driving force from the mainspring 2 is individually taken out to the drum 4 and the speed adjusting means serving as a governor.

The No. 4 worm 17 constitutes the final stage of the speed increasing train wheel 6, and the rotating body 70 of the braking means 7 is arranged on the tip end side thereof. The speed increasing train wheel 6 having such a configuration is covered by the gear housing portion 62 formed in the case 8 to prevent intrusion of dust or foreign matter from the outside.

The third worm 15 is arranged closer to the mainspring 2 (deceleration side) than the fourth worm 17, and is the first worm. Also, the third worm 15 is the first
The gear 12 is arranged above the case 8 side. 3
As shown in FIG. 7, when the rotation is transmitted from the No. 2 worm wheel 14 to the No. 3 worm 15, that is, when the No. worm 15 is driven by the driving force of the mainspring 2, the No. worm 15 has an arrow C on the No. 3 worm 15. , D are provided so as to be pressed against the bearing portion 31 formed on the case 8 by the biasing force acting in the thrust direction and the radial direction. The bearing portion 31 is an inverted U-shaped groove opened downward, and restricts the shaft portion 15a of the No. 3 worm 15 from moving upward and sideward.

As shown in FIG. 8, a flange 30 is provided at the lower end of the No. 2 worm wheel 14, and the No. 3 worm 15 when the rotation is not transmitted is supported by the flange 30. .

As shown in FIGS. 7 and 9, the shaft portion 15b of the No. 3 worm 15 formed on the side opposite to the shaft portion 15a is formed in the inner wall 8A of the case 8 in an inverted U-shape with respect to the frame 1. The bearing portion 32 and the convex portion 33 protruding from the frame 1 side and fitted to the bearing portion 32 are sandwiched and rotatably supported. A tongue piece 44 as a position holding member that slightly biases the No. 3 worm 15 toward the bearing portion 31 located in the direction of the biasing force indicated by the arrow C outside the bearing portion 32 that supports the shaft portion 15b. Is integrally formed with the case 8. This tongue piece 44 is made of resin like the case 8, and is shown in FIG.
As shown in FIG. 1, the case 8 is placed in the space 45 formed by the inner wall 8A and the side wall 8B of the case 8 and the frame 1
It is an elastic piece that protrudes toward and lightly contacts the shaft end 15c of the No. 3 worm 15.

As shown in FIGS. 7 and 8, a No. 3 worm wheel 16 is formed at the intersection of the No. 3 worm 15 and No. 4 worm 17, and a No. 4 worm 1 is formed on the No. 3 worm wheel 16.
7 are arranged and meshed. 4th worm 17
As shown in FIG. 2, one end is inserted into the bearing portion 34 formed in the fixed wall portion 60 of the case 8, and the other end is formed into the worm wheel 16 and the case 8 and the reverse U is formed.
The No. 2 gear 13, the No. 2 worm wheel 14, and the flange 30, which are rotatably supported by the character-shaped bearing portion 35, are integrally molded of plastic or metal as required, and as shown in FIG. 8 is rotatably supported by a shaft 63 that is integral with the case 8 and projects from the frame 8 toward the frame 1. The shaft 63 projects from the ceiling surface of the gear housing portion 62 toward the frame 1 side. The tip 63a of the shaft has a support hole 36 formed in the frame 1.
And is supported by the frame 1 and the case 8 and supports the No. 2 gear 13 and the No. 2 worm wheel 14 near the frame 1.

As shown in FIG. 2, the braking means 7 is composed of a rotating body 70 made of an elastic body such as rubber or a rubber-like product, and a fixed wall portion 60 with which the rotating body 70 contacts.
The rotating body 70 is formed so as to be displaced in the axial direction by receiving a centrifugal force, and is press-fitted to the shaft portion of the No. 4 worm 17 that rotates at a high speed. The fixed wall portion 60 is formed with a wall surface (not shown) that comes into sliding contact with the rotating body 70 when the rotating body 70 is displaced.
It comes into sliding contact with and applies frictional braking. This friction braking is performed by the speed increasing train wheel 6 and the drum 4 connected to the speed increasing train wheel 6.
Keeps the rotation constant.

An opening space 73 for rotatably accommodating the rotating body 70 is formed near the fixed wall portion 60. By inserting a stopper or the like (not shown) from this space 73,
It is also possible to stop the rotating body 70.

According to the music box having such a structure, when the first gear 12 rotates due to the release of the mainspring 2, the rotation is accelerated by the speed increasing gear train 6 to rotate the rotating body 70 at a high speed, and thus the rotating body 70. Is brought into sliding contact with the fixed wall portion 60 to brake the rotation of the first gear 12 of the drum 4 to keep the rotation of the drum 4 constant. At this time, since the weak urging force of the tongue piece 44 in the arrow C direction acts on the No. 3 worm 15, the axial movement of the No. 3 worm 15 is stably prevented. Further, since the biasing force acts in the direction of arrow C on the No. 3 worm 15 at this time by the rotation of the gear, the tongue piece 4
The urging force of 4 is small.

On the other hand, the drum 4 is used for the stored power of the mainspring 2.
When the meshing load between the vibration plate 5 and the vibration plate 5 is large, that is, when the stored force of the mainspring 2 decreases, the inertial force of the rotating body 70 attached to the fourth worm 17 located on the speed increasing side serves as the driving force. It is transmitted to the third worm 15. Then
A biasing force in the direction indicated by the arrow E in FIG. 7 acts on the third worm 15, and tends to move to the right in the figure. But 3
Since the tongue piece 44 is in contact with the end portion 15c of the No. worm 15, the movement of the No. 3 worm 15 in the axial direction is restricted. If the biasing force in the arrow E direction due to the input from the fourth worm 17 on the speed increasing side is large, the third
Since the worm wheel 16 contacts the inner wall 8A of the case, damage to the tongue piece 44 can be prevented.

Further, even if the biasing force from the mainspring 2 side shown by arrow C becomes larger than the biasing force in the direction of arrow E,
Since the third worm 15 is always urged by the tongue piece 44 in the direction of the biasing force indicated by the arrow C, the meshing state with the second worm wheel 14 is stable.

That is, even if the biasing forces acting on the third worm 15 are switched to opposite directions (arrow E directions), the tongue piece 44 restricts the movement of the worm 15 in the axial direction. The play in the speed increasing train 6 is extremely reduced. Therefore, the braking force of the braking means 7 is stably transmitted to the drum 4, the rotation of the drum 4 is stabilized, and the sounding state of the music is improved and the sound quality is also improved.

Further, the bearing portions 31, 32 and the third worm 1
The movement of the third worm 15 is restricted by the tongue piece 44 even if a certain amount of play is provided between the speed increasing gear train 6 and the frame 1.
Since the accuracy of the case 8 and the case 8 can be widened, the cost reduction effect can be obtained.

In the present embodiment, the tongue piece 44 is an elastic piece integrally molded with the case 8, but it is constructed as a separate member to the case 8 and can be attached later, or the upper surface 1a of the frame 1 can be formed.
The tongue piece 44 may be replaced with a leaf spring or the like. In any case, it is essential that the position holding member has elasticity, and by having this elasticity, the durability of the position holding member is improved and a degree of freedom in the positional relationship with the third worm 15 is obtained.

[0039]

According to the invention described in claim 1, even if the direction of the biasing force to the first worm located on the drive source side in the speed increasing train wheel having the two stages of worms is switched, the position holding means is used. Since the movement of the gear in the thrust direction is prevented, the play of the speed increasing gear train due to the biasing force can be extremely reduced. Accordingly, the braking force of the braking means is constantly applied to the drum, the drum can be stably rotated, and the music box has good sound quality and can play a good song.

According to the second aspect of the present invention, the position holding means makes the first position in the direction of the biasing force generated when driven by the driving source.
Since the worm is urged, the movement of the first worm in the thrust direction is regulated more stably, and the music box has a better sound quality and can play a good song.

According to the third and fourth aspects of the invention, the position holding means is an elastic piece or a tongue piece, so that the contact state with the first worm becomes elastic, and the sound of a good tune with good sound quality is produced. In addition to being able to perform, it becomes a music box with good durability of the position holding means.

According to the fifth aspect of the present invention, by providing the mainspring winding shaft substantially at the center of the frame, it is possible to produce a good tune with good sound quality and a well-balanced music box.

[Brief description of drawings]

FIG. 1 is a perspective view of a music box showing an embodiment of the present invention.

FIG. 2 is a partially cutaway plan view of the music box shown in FIG.

FIG. 3 is an enlarged cross-sectional view showing a drum of the music box shown in FIG. 1 and its supporting structure.

FIG. 4A is a plan view showing an example of a ratchet that connects a winding shaft and a first gear, and FIG. 4B is a longitudinal sectional view thereof.

5 is a front view of the music box shown in FIG. 1. FIG.

FIG. 6 is a side view showing the structure of a speed increasing train wheel.

FIG. 7 is an explanatory view showing the relationship between the support structure for the No. 3 worm in the speed increasing train wheel, which is the main part of the present invention, and other gears meshing with it.

FIG. 8 is an explanatory diagram showing a relationship between a No. 3 worm, a No. 2 worm wheel, and a flange.

FIG. 9 is an enlarged perspective view showing a support structure for a No. 3 worm, which is an essential part of the present invention.

FIG. 10 is a partial cross-sectional view of a case showing a configuration of position holding means.

[Explanation of symbols]

 1 frame 2 drive source (spring) 3 winding shaft 4 drum 5 vibrating plate 5a vibrating valve 6 speed increasing wheel train 7 braking means 8 barrel (case) 15 first worm (3rd worm) 17 4th worm 31, 32 bearing 44 Position holding member

Claims (5)

[Claims] 1. A vibrating plate having a comb-tooth-shaped vibrating valve, a drum for playing a tone by flipping the vibrating plate, a drive source for rotationally driving the drum, and a rotational speed of the drum. In the music box in which the speed-controlling means to be supported is supported on the frame, the speed-controlling means includes a speed increasing train wheel having two stages of worms,
Positioning means for stopping the movement in the thrust direction of at least the first worm located at least on the drive source side of the two-stage worms, the braking means being provided at the final stage of the speed increasing train wheel. A music box arranged on the frame. 2. The music box according to claim 1, wherein the position holding means biases the first worm in a direction of a biasing force generated when the first worm is driven by the drive source. 3. The first worm has a shaft, which is pivotally supported by a bearing formed on the frame,
The music box according to claim 1 or 2, wherein the end portion of the shaft is urged by contacting an elastic piece constituting the position holding means. 4. The elastic piece is a tongue piece integrally formed with a barrel box surrounding the drive source.
The described music box. 5. The music box according to claim 1, wherein the drive source is a mainspring, and a winding shaft of the mainspring is arranged substantially in the center of the frame.