JP2017064001A - Rotary drive device increasing rotational speed of rotating body by twist of rubber string - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend an operation time by increasing the number of times of twisting of a rubber string and increasing the rotational speed of a rotating body of a toy without being greatly restricted by the size and length of the toy, in the toy for rotating the rotating body by twisting the rubber string.SOLUTION: Multiple rubber strings 1, 2 are provided and adjacent rubber strings 1, 2 are mutually connected by the rotational connection structure of ends in a connection direction, and thereby a rotating body 6 is rotated with the total number of times obtained by adding the number of times of twisting of the multiple rubber strings 1, 2 to extend the operation time of the rotating body 6 of the toy.SELECTED DRAWING: Figure 1

Description

  The present invention is used for models and toys such as automobiles, windmills, and ferris wheels, which use the twist of a rubber string as a power source.

Conventionally, there has been dissatisfaction that the operation time for running in a toy that rotates a rotating body by twisting a rubber string, such as an automobile, is short (for example, see Patent Document 1). In order to lengthen the operation time, it is required to increase the number of twists of the rubber string and increase the number of rotations of the rotating body.

The number of twists that can be twisted without cutting the rubber string increases as the thickness of the rubber string decreases and the length increases. However, since the thickness is determined to be a thickness that can rotate the toy rotating body, it is necessary to lengthen the rubber string in order to increase the number of twists. However, the length of the rubber string to be used cannot normally be larger than the size / length of the toy because of the design of the toy. As described above, the number of twists of the rubber string is almost determined by the size and length of the toy, and cannot be increased any further. There was a big problem that time was short.

JP 2010-253241-A

  Conventionally, a toy that rotates a rotating body by twisting a rubber string has a problem that its operating time is almost determined by the size and length of the toy and the operating time is short. The reason for using rubber as power is that it is easy to use and inexpensive, but there is a problem that the technology for satisfying them is insufficient.

This invention makes it a subject to provide the method of lengthening the rotation operation time of a toy with the simple and cheap method with respect to the above problems.

  A method and means for solving the above problems will be described. When rotating a rotating body by twisting a rubber string, conventionally, a single rubber string is hung between the rotating body and a rotating handle, and the rotating body is rotated by twisting the single rubber string. It was. Accordingly, the number of rotations that can be rotated is limited to the number of twists of one rubber cord. In the present invention, a plurality of rubber strings are provided, for example, in series, the plurality of rubber strings are twisted, and the rotating body is rotated by the total number of times of twisting. As a result, compared with the conventional one, the number of rotations of the toy was greatly increased without increasing the length of the rubber cord.

FIG. 1 is a conceptual diagram in the case of two rubber strings. One end of the first rubber cord 1 is hooked on the hook of the rotary handle 3 and the other end is hooked on the hook of the first pulley 4. One end of the second rubber cord 2 is hooked on the hook of the second pulley 5, and the other end is hooked on the hook of the rotating body 6. The shafts of pulley 4, pulley 5, rotating handle 3 and rotating body 6 are supported by bearing material 7, and a ball seat 8 is inserted and fixed to the shaft in order to reduce friction with bearing material 7. Has been. By connecting the first pulley 4 and the second pulley 5 with a belt 9, the first rubber cord 1 and the second rubber cord 2 are connected in series, and the rotating body 6 is a screw of two rubber cords. Rotation by twisting is possible.

FIG. 2 is a conceptual diagram when there are three rubber strings. One intermediate rubber cord 10 is disposed between the connection directions of the first rubber cord 1 and the second rubber cord 2. Both ends of the intermediate rubber cord 10 are hooked on the hooks of the pulley 11 and the pulley 12, and the shafts of the pulleys 11 and 12 are supported by the bearing members 7, respectively. A ball seat 8 is inserted and fixed. The pulley 4 at the other end of the first rubber cord 1 and the pulley 11 at one end of the intermediate rubber cord 10 are connected by a belt 13, and the pulley 5 at one end of the second rubber cord 2 and the intermediate rubber cord. By connecting the pulley 12 at the other end of the belt with the belt 14, the first rubber cord 1 and the second rubber cord 2 are connected in series via the intermediate rubber cord 10, and the rotating body 6 is equivalent to three pieces. It can be rotated by twisting the rubber string.

Even when there are more than three rubber cords, the first rubber cord to the second rubber cord are connected in series by increasing the intermediate rubber cord and connecting the intermediate rubber cords adjacent to each other in the connecting direction. The rotating body can be rotated by twisting corresponding to the number of rubber strings.

Here, when the rubber cords are arranged in parallel, it is necessary to align the ends of the two pulleys connected by the belt. Further, when the rubber strings adjacent in the connection direction are arranged at an angle such as a right angle, the two pulleys to be connected need to have the centers aligned and have a height difference. Each of the plurality of rubber strings has a unique length and thickness, and the length is determined by the design, shape, structure, etc. of the toy. The thickness is gradually increased from the output side of the rotating body toward the input side of the rotary handle in order to correct the influence of friction in the pulley connection structure and the like. In order to prevent slippage between the belt and pulley, the surface of the pulley is roughened by sandpaper sticking, etc., and the belt absorbs manufacturing errors and layout errors. In order to make it possible, a belt is formed by hanging a plurality of thin strings individually instead of a single thick string or belt.

  When you start twisting the rubber strap, you will get a primary bulge that swells slightly at first. Further twisting produces a secondary aneurysm on the primary aneurysm, and a tertiary aneurysm on the primary aneurysm. In general, toys are not twisted before and after the occurrence of secondary aneurysm over the entire length in order to avoid cutting the elastic cord.

When the rotating body is stopped and the rotary handle is rotated, the first rubber string is twisted, and the rotation of the first pulley at the other end starts almost simultaneously, and the rotation is transferred to the next pulley via the belt. The intermediate rubber string in front is twisted. When the rotating handle is further rotated, the first rubber cord and the intermediate rubber cord in front are twisted, and the rubber in the front is further passed through the pulley at the other end of the intermediate rubber cord in front. The string is twisted. By continuing the rotation of the rotary handle in this manner, all the rubber strings from the first rubber string to the second rubber string including the plurality of intermediate rubber strings are twisted.

After each rubber cord is twisted before and after the occurrence of the secondary aneurysm over the entire length, when the rotating body is removed, the twisting of the second rubber string returns and the rotating body rotates. When the twisting of the second rubber cord is reduced, the twisting of the intermediate rubber cord behind the second rubber cord is returned, whereby the second rubber cord is newly twisted. When the twist of the intermediate rubber cord behind is reduced, the twist of the intermediate rubber cord further rearward in the connecting direction is returned, and the rear intermediate rubber cord is newly twisted. By such repetition, the twisting of all the rubber strings from the second rubber string to the first rubber string including the plurality of intermediate rubber strings is returned. When the friction between the pulleys is small, the rotating body rotates in accordance with the number of twists of a plurality of rubber cords, and the operation time becomes longer than in the case of one rubber cord, The problem that the operation time of the toy by the conventional rubber cord is short is solved.

The thickness of each of the plurality of rubber cords is determined in consideration of the friction generated between the pulleys. The second rubber string needs to be thick enough to rotate the rotating body. If the thickness of the second rubber cord is determined, the thickness of the intermediate rubber cord and the first rubber cord may basically be supplemented with friction. That is, the intermediate rubber cord behind the second rubber cord has a predetermined number of twists, and needs to be thick enough to twist the loose second rubber cord to a predetermined number. Become thicker. Similarly, the thickness of the first rubber cord needs to be thick enough to twist the intermediate rubber cord in front with a predetermined number of twists up to the predetermined number of twists. Become thicker. As a result, the thickness of the rubber string gradually increases from the rotating body toward the rotating handle.

Claims 2 and 6 describe the case where the lengths of the rubber cords are different. In this case, it is extremely difficult to determine the thickness of the rubber cords in advance, but the pulleys are arranged by the method described above. After that, the thickness of each rubber cord can be determined. Thus, it is also a feature of the present invention that the length and thickness of the rubber string can be easily determined from the shape of the toy and subsequent investigations, etc. When a commercially available rubber band is used as the rubber string, the length is plural. By connecting the rubber bands, the thickness can be determined by increasing / decreasing the number of the rubber bands according to the above-described method, so that the correspondence is easy.

Specifically, in order to rotate the rotating body that is the target of the toy, the present invention mainly reduces the friction between the bearing material, the pulley, the rubber cord, the belt, the pulley and the bearing material that receive the pulley shaft. It consists of a ball seat and a rotating handle to reduce, both satisfying the simple and inexpensive requirements that are necessary conditions for selecting rubber power in toys. If these members are complex and expensive, they can be replaced by other power, conduction motors, etc., and rubber straps are not used in toys.

  As described above, the major problem that the operating time of a rotating body in a toy that uses torsion of a rubber cord as a power source is short is to rotate without lengthening the rubber cord that is restricted by the size and length of the toy. It was solved by increasing the number of rotations of the body. The reason why rubber is selected as the power of the toy is that the mechanism is simple and inexpensive, and the present invention satisfies this condition.

Conceptual diagram when there are two rubber strings Conceptual diagram when there are three rubber strings Top view of a traveling vehicle toy Side view of a traveling vehicle toy Sectional view of the rear wheel position of a toy vehicle Explanatory drawing of rotating handle when rotating clockwise and counterclockwise Top view of a ferris wheel toy Front view of a ferris wheel toy Side view of Ferris wheel and rotating body in Ferris wheel toy

  Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) FIG. 3 is a plan view, FIG. 4 is a side view, and FIG.

  A rectangular frame-shaped main body frame 21 is partitioned by a first partition member 22a and a second partition member 22b to form a first section A, a second section B, and a third section C. The bearing member 23 passes through the first partition member 22a from the rear side of the main body frame 21 on one side of the left and right sides of the main body frame 21 to reach the second partition member 22b, and the bearing member 24 is on the other left and right sides of the main body frame 21. From the rear side of the main body frame 21 to the first partition member 22a.

The shaft of the first pulley 28a in the first section A is supported by the left and right frame portions of the main body frame 21 and the bearing member 23, and the rear wheel 25 is supported by the shaft of the first pulley 28a as an empty wheel. However, it is not bonded to the shaft, and is rotatable with respect to the shaft of the first pulley 28a. The rear wheel 26 is a rotating body targeted by the present invention, and its shaft is supported by the left and right frame parts of the main body frame 21 and the bearing member 24, and sandpaper is provided on the outer peripheral surface so as not to idle with respect to the running surface. Is affixed.

The shaft of the second pulley 28b in the second section B is supported by the left and right frame portions of the main body frame 21 and the bearing member 23, the rotary handle 32 has a crank shape, and the left and right other sides of the main body frame 21. It is rotatably supported by the frame part. The rotation handle 32 has a reverse rotation prevention tool. As shown in FIGS. 6a and 6b, one end of the anti-reverse device is hinged to the other frame of the main body frame 21, and the other end with a small piece of lead is the crank portion of the rotary handle 32. Rotation is achieved by the structure of the thin plate 33 having a length that can contact with the main body frame 21 and the reverse rotation preventing projection 34 provided on the other frame portion of the main body frame 21 so that the thin plate 33 does not fall downward. As shown in FIG. 6a, the handle 32 is free to rotate in the clockwise direction for twisting the rubber string, and can be freely rotated while repeating the lifting of the thin plate 33. As shown in FIG. 6 b, the thin plate 33 is not possible because it is blocked by the reverse rotation prevention protrusion 34.

The front wheel 27 of the third section C is an empty wheel, and the shaft is supported at an angle to the left and right frame parts of the main body frame 21 so that the traveling vehicle turns. It is free to rotate.

The first pulley 28a and the second pulley 28b have a rigidity that supports the pulley in a straight line by sticking a circular cardboard that is slightly larger than the outer peripheral surface of the annular member on both sides of the circular annular member made of cardboard. A wire is used as a shaft and penetrates the center of the pulley and is bonded to the pulley. Sandpaper is affixed to the outer peripheral surface to prevent slippage with the belt. The belt 29 that connects the pulleys 28a and 28b is used to hang a plurality of thin octopus yarns individually instead of a single thick string or belt so as to absorb a manufacturing error or an arrangement error of the pulleys. And a belt.

One end of the first rubber cord 30a in the first section A is hooked on the hook of the first pulley 28a, and the other end is hooked on the hook of the rear wheel 26. One end of the second rubber cord 30b of the second section B is hooked on the hook of the rotary handle 32, and the other end is hooked on the hook of the second pulley 28b. The first rubber cord 30a and the second rubber cord 30b are different in length and thickness. The first rubber cord 30a is a collection of four rubber bands of size number 18, and the second rubber string 30b is rubber band of size number 18. Two are connected, and eight of them are put together. That is, the second rubber cord 30b is longer and thicker than the first rubber cord 30a. A ball seat 31 is inserted and fixed to the shafts of the first pulley 28 a, the second pulley 28 b, the rear wheel 26 and the rotary handle 32 in order to reduce friction with the main body frame 21.

Hold the vehicle, stop the rear wheel 26 which is a moving wheel, and manually turn the handle 32 clockwise to twist the first rubber cord 30a and the second rubber cord 30b until the secondary aneurysm occurs over the entire length. Then stop turning. The handle 32 that has stopped rotating is put in a stopped state even if the hand is released by the reverse rotation prevention tool.

When the vehicle is released, the torsion of the rubber of the first rubber string 30a returns, and the rear wheel 26 rotates to advance the vehicle. When the rubber of the first rubber cord 30a is loosened, the twist of the second rubber cord 30b returns, the second pulley 28b is turned and the first rubber cord 30a is rotated by the belt 29 via the first pulley 28a. Twisted again. Through this repetition, the vehicle continues to travel until the first rubber cord 30a and the second rubber cord 30b are completely twisted. In the case of the present embodiment, the turning motion having a diameter of 1.7 m was performed about 6 times. The total travel distance reached about 32 m, and the operation time of the toy by twisting the rubber cord could be extended.

For a traveling vehicle such as the present embodiment, even when a further increase in the travel distance is required, the rubber string train is three-dimensionally formed without increasing the length of the rubber string and changing the size and length of the vehicle. It can be easily handled by increasing the number of the rubber string by arranging it.

As described above, if the present invention is used, a toy such as a traveling vehicle having a long operation time can be easily, easily and inexpensively manufactured.

(Embodiment 2) With respect to the next embodiment of the present invention, a toy for a ferris wheel using three rubber strings having the same length as a power source will be described with reference to the drawings. The plane of the toy of the Ferris wheel is shown in FIG. 7, the front is shown in FIG. 8, and the sides of the Ferris wheel and the rotating body are shown in FIG.

The actual rotation of the Ferris wheel is very slow, and it is necessary for the toy to rotate slowly. The rotation of the rubber string itself is extremely fast and it is too fast for the ferris wheel to rotate, so a method of decelerating with a reduction mechanism that transmits the rotation from the small diameter pulley to the large diameter pulley is required. Become. In this speed reduction mechanism, a very large number of twists of the rubber string are consumed for one rotation of the ferris wheel, and therefore, it is required to increase the number of twists of the rubber string as much as possible. Three rubber strings are provided to increase the number of times the rubber is twisted to solve this problem.

In FIG. 7, a first horizontal bearing member 41a is fixed to the front side of the main body frame and a second horizontal bearing member 41b is fixed to the rear side of the main body frame 40a having a rectangular frame shape supported by the support legs 40b at the four corners. The shaft of the rotation handle 42a and the third pulley 43c is supported by the front frame portion of the main body frame 40a and the first lateral bearing member 41a. The rotating handle 42a has a crank shape and is rotatably supported by a front frame portion of the main body frame 40a. The rotation handle 42a is provided with anti-reverse tools 42b and 42c. As shown in FIGS. 6a and 6b, the rotation handle 42a can be rotated clockwise to twist the rubber string, but in the opposite direction. It is not possible to go to. The reverse rotation prevention tools 42b and 42c are basically the same in structure and function as the reverse rotation prevention tools 33 and 34.

The shafts of the first pulley 43a and the second pulley 43b are supported by the second lateral bearing member 41b and the frame portion on the rear side of the main body frame 40a, and the fourth pulley is positioned higher than these pulleys. There is a pulley 44a and a pulley 44b which is a rotating body, and the shaft of the fourth pulley 44a includes a first vertical bearing member 46a fixed to the front frame portion of the main body frame 40a, and a first horizontal bearing member. The shaft of the rotating body 44b is fixed to the third vertical bearing member 46c fixed to the second horizontal bearing member 41b and the rear frame portion of the main body frame 40a by the second vertical bearing member 46b fixed to 41a. It is supported by the fourth vertical bearing member 46d. The shafts of the first pulley 43a, the second pulley 43b, the third pulley 43c, the fourth pulley 44a, and the rotating body 44b reduce friction with the frame portion of the main body frame 40a. The ball seat 45 is inserted and fixed.

The first rubber cord 49a is attached to the hook of the rotary handle 42a and the first pulley 43a, and the second rubber cord 49b is attached to the hook of the second pulley 43b and the third pulley 43c. A third rubber string 49c is hung on the hooks of 44a and 44b. These rubber cords are made by connecting two commercially available rubber bands of size number 18, consisting of 12 for the first rubber cord 49a, 9 for the second rubber cord 49b, and 6 for the third rubber cord 49c. ing. In other words, the first rubber cord 49a, the second rubber cord 49b, and the third rubber cord 49c have the same length and are gradually reduced in thickness. The first pulley 43a and the second pulley 43b are first belts 47a in which a plurality of octopus yarns are individually hung, and the third pulley 43c and the fourth pulley 44a are also a plurality of octopus yarns individually. It is connected by a second belt 47b that is hung.

The shaft of the ferris wheel 50 is supported by the first gate-type member 51a and the second gate-type member 51b, and a fifth pulley 52 having a diameter larger than that of the rotating body 44b is fixed to the shaft. The pulley 52 is connected by a third belt 53 of one octopus thread so that the rotation of the rotating body 44b is decelerated.

The ferris wheel 50 or the rotating body 44b is stopped, and the rotary handle 42a is manually rotated clockwise to generate a secondary knob over the entire length of the first rubber cord 49a, the second rubber cord 49b, and the third rubber cord 49c. After that, when the ferris wheel 50 or the rotating body 44b is removed, the twist of the third rubber string 49c is first returned, and the rotating body 44b is rotated, and transmitted to the pulley 52 of the ferris wheel by the third belt 53. Then the Ferris wheel starts to turn. When the twist of the third rubber cord 49c is reduced, the twist of the second rubber cord 49b is returned, and the third rubber cord 49c is twisted again. The second rubber string 49b is also twisted again by the return of twisting of the first rubber string 49a. In this way, the Ferris wheel continues to rotate until there is almost no twisting of the three rubber strings.

In this embodiment, the total number of twists of the rubber cord is increased to 150 times, almost three times as long as one row, and the fifth pulley 52 is reduced to 90 mm with respect to the diameter of 30 mm of the rotating body 44b. The number of rotations is 50 times in 15 seconds, and compared to the number of rotations of about 10 seconds in about 5 seconds, which is expected when there is only one rubber string, the rotation speed of the Ferris wheel has been achieved. It was too fast. If the desired speed is 50 revolutions per minute, the total number of twists must be 600 and the diameter of the fifth pulley 52 of the ferris wheel must be 360 mm in order to achieve the pulley speed reduction mechanism alone. None of them are difficult to realize as toys. As described above, it is extremely difficult to achieve a very slow rotational speed with only a speed reduction mechanism such as a pulley with rubber power having a limit in the number of twists.

In order to obtain a desired rotation speed, in this embodiment, in addition to the speed reduction mechanism by the pulley, the circular plate 54 in the rotation speed adjusting device is attached to the shaft of the rotation body pulley 44b, and the rotation speed of the rotation body 44b is directly set. A method of slowing down was adopted. One end of a band 55 having a predetermined length that is narrower than the outer peripheral surface is bonded to the outer circumferential surface of the circular plate 54, and the band 55 is released by gravity or centrifugal force accompanying the rotation of the circular plate 54. However, the rotation is constrained, and the rotational speed of the rotating body 44b is made gentle and at a substantially constant speed.

By combining the increase in the number of twists and the rotational speed adjusting device according to the present invention, the ferris wheel of the present example achieved a desirable rotation of 50 times per minute.

For example, in a model or toy such as an automobile, a windmill, a ferris wheel, etc. having a rotating body, when the rubber string is used as a power source, it is difficult to lengthen the operating time of the rotating body and it is not attractive. There are not many toys. According to the present invention, it is possible to manufacture toys that are inexpensive and have a long operation time easily, and various toys that are not conventionally available can be expected.

1: 1st rubber cord:
2: Second rubber string 3: Rotating handle 4: First pulley 5: Second pulley 6: Rotating body 7: Bearing material 8: Ball seat 9: First pulley and second pulley Connecting belt 10: Intermediate rubber string 11: Pull at one end of the intermediate rubber string 12: Pull at the other end of the intermediate rubber string 13: Pull at the first pulley and one end of the intermediate rubber string Belt 14 connecting the pulley of the other end of the intermediate rubber string and the second pulley A: first section B of the traveling vehicle toy second section C of the traveling vehicle toy C: second of the traveling vehicle toy 3 sections 21: main frame 22a of the traveling vehicle toy: first partition material 22b of the traveling vehicle toy: second partition material 23 of the traveling vehicle toy 23: bearing material 24 on one side of the traveling vehicle toy 24: on the other side of the traveling vehicle toy Bearing material 25: Rear wheel 26 on one side of the traveling vehicle toy: Rear wheel 27 on the other side of the traveling vehicle toy: Front wheel 28a of the traveling vehicle toy: 1 pulley 28b: second toy of traveling vehicle toy 29: belt 30a of traveling vehicle toy: first rubber string 30b of traveling vehicle toy: second rubber string of traveling vehicle toy 31: ball seat of traveling vehicle toy 32: Rotating handle of traveling vehicle toy 33: Thin plate of reversing prevention tool for traveling vehicle toy 34: Protrusion of reversing preventing tool for traveling vehicle toy 40a: Body frame of ferris wheel toy 40b: Support leg of body frame of ferris wheel toy 41a: Ferris wheel toy first lateral bearing material 41b: Ferris wheel toy second lateral bearing material 42a: Ferris wheel toy rotating handle 42b: Ferris wheel toy reversing prevention tool thin plate 42c: Ferris wheel toy preventing reverse rotation Tool projection 43a: Ferris wheel toy first pulley 43b: Ferris wheel toy second pulley 43c: Ferris wheel toy third pulley 44a: Ferris wheel toy fourth pulley 44b: Viewing Car toy rotary body 45: Ferris wheel toy base 46 : Ferris wheel toy first vertical bearing material 46b: Ferris wheel toy second vertical bearing material 46c: Ferris wheel toy third vertical bearing material 46d: Ferris wheel toy fourth vertical bearing material 47a: Ferris wheel toy first 1 belt 47b: second belt 49a of the Ferris wheel toy: first rubber string 49b of the Ferris wheel toy: second rubber cord 49c of the Ferris wheel toy: third rubber string 50 of the Ferris wheel toy: ferris wheel 51a of the Ferris wheel toy : Ferris wheel toy first gate type member 51b: Ferris wheel toy second gate type member 52: Fifth pulley fixed to the ferris wheel shaft 53: Ferris wheel toy third belt 54: Ferris wheel Circular version 55 with toy belt: Circular belt with ferris wheel toy belt

Claims (8)

  A rotary drive device that rotationally drives a rotating body, the first rubber cord having a twist handle for rotation at one end, and the other end of the first rubber cord via a connection structure A second rubber string connected to the rotating body and connected at the other end to the one end of the second rubber string from the other end of the first rubber string. A rotary drive device configured to transmit force, wherein the first rubber cord is set to be thicker than the second rubber cord.   The rotation driving device according to claim 1, wherein the first rubber cord and the second rubber cord have different lengths.   The first rubber cord and the second rubber cord are arranged at an angle such as a right angle, and the connection structure is a belt that connects the other end portion of the first rubber cord and the one end portion of the second rubber cord. The rotary drive device according to claim 1, wherein the rotary drive device is a vehicle structure.   The connection structure has a first pulley which is a rotation conducting member having a hook connected to the other end of the first rubber cord, and a hook connected to the one end of the second rubber cord. A belt having a second pulley and a transmission string stretched between the first pulley and the second pulley, and for preventing slipping, a plurality of thin strings are individually hung as belts; and The rotary drive device according to claim 1, 2 or 3, wherein the outer surface of the first pulley and the second pulley is roughened by sandpaper sticking or the like.   A rotational drive device for rotationally driving a rotating body, comprising: a first rubber string on an input side provided with a twisting rotary handle at one end; and an output side first connected to the rotating body at the other end. Two rubber cords, and one or a plurality of intermediate rubber cords connected in series via a connection structure between the other end portion of the first rubber cord and one end portion of the second rubber cord, The connection structure is configured such that a rotational force is transmitted from the other end portion of the first rubber cord to the one end portion of the second rubber cord via the intermediate rubber cord, and the first rubber cord. The thickness of the intermediate rubber cord and the second rubber cord gradually increases from the output side toward the input side.   6. The rotary drive device according to claim 5, wherein at least one of the first rubber cord, the intermediate rubber cord and the second rubber cord is different in length from other rubber cords. Among the pair of rubber cords adjacent in the connecting direction, including those arranged at an angle of right angle or the like, the pair of rubber cords arranged at an angle of right angle or the like are connected by a belt wheel structure. The rotation drive device according to claim 5 or 6, wherein The connection structure includes a first pulley having a hook connected to the other end portion of the first rubber cord, and a hook connected to one or more end portions of the intermediate rubber cord. An intermediate pulley, a second pulley having a hook connected to the one end of the second rubber cord, and a connecting direction of the first pulley, the intermediate pulley, and the second pulley; Belts that are stretched between adjacent pulleys, and sandpaper is applied to the outer peripheral surfaces of the first pulley, intermediate pulley, and second pulley to prevent the belt from slipping. 8. The rotary drive device according to claim 4, wherein a plurality of thin cords are individually hung as a belt.