JP2003267488A - Lid closing mechanism and lid closing apparatus having a plurality of lid closing mechanisms - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to easily and quickly change a transmission torque without carrying out a cumbersome operation such as alteration of a fixed position of a component or the like, by improving a lid closing mechanism (14). <P>SOLUTION: The lid closing mechanism comprises a torque regulating coupling means (20a, 20b), which comprises pairs of magnetic means (80a, 82a, 80b, 82b), each magnetic means arranged to be apart from and opposed to each other to form each pair, and conductive members (84a, 84b) each of which is arranged between each pair of magnetic means to generate eddy currents. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lid fastening mechanism for fastening a lid to the mouth and neck of a container, and more particularly to a male thread formed on the mouth and neck of the container and formed on the skirt wall of the lid. The present invention relates to a lid fastening mechanism for screwing together female threads to attach a lid to the mouth and neck of a container to seal the mouth and neck, and a lid fastening device including a plurality of such lid fastening mechanisms.

[0002]

BACKGROUND OF THE INVENTION As is well known to those skilled in the art, a container which can be formed from a suitable synthetic resin such as polyethylene terephthalate or glass has a cylindrical mouth-neck portion having an open top surface. A male thread is formed on the outer peripheral surface of the neck. The lid that is attached to the mouth and neck of the container to seal the mouth and neck can be made of an appropriate synthetic resin such as polyethylene or polypropylene or a thin metal plate, and has a circular top wall and a cylinder that hangs from the periphery of the top wall. And a female skirt is formed on the inner peripheral surface of the skirt wall. When the lid is attached to the mouth and neck of the container to seal the mouth and neck, the required torque is applied to the male thread formed on the mouth and neck of the container with the female thread formed on the skirt wall of the lid. It is important to screw together. If the screwing torque is too small, the mouth and neck will not be sufficiently sealed.If the screwing torque is too large, the torque required to open the mouth and neck by removing the lid from the mouth and neck will be too large. I will end up.

Therefore, in the lid tightening mechanism used to attach the lid to the mouth and neck of the container, the input rotating member connected to the rotary drive source, which may be an electric motor, and the chuck means for holding the lid are connected. The torque limiting joint means is interposed between the output rotating member and a predetermined torque, that is, the maximum torque transmitted by the torque limiting joint means is applied to the lid when the lid is attached to the mouth and neck of the container. I am trying. In the lid tightening mechanism disclosed in Japanese Unexamined Patent Application Publication No. 8-207993, a torque limiting joint means composed of a pair of magnet means arranged facing each other with a space is provided.
It is arranged between the input rotary member and the output rotary member. Each of the pair of magnet means is formed of a plurality of segment magnets arranged in a ring shape as a whole, and one of the pair of magnet means is fixed to the input rotary member and the other is fixed to the output rotary member. The torque is transmitted via the magnetic attraction force between the pair of magnet means.

In the lid tightening mechanism disclosed in Japanese Patent No. 2912541, a pair of magnet means arranged facing each other with a space therebetween and a strong hysteresis loss arranged between the pair of magnet means are large. Torque limiting coupling means including a magnetic member is arranged between the input rotary member and the output rotary member. The pair of magnet members are fixed to one of the input rotating member and the output rotating member, and the ferromagnetic member is fixed to the other of the input rotating member and the output rotating member. The torque is transmitted by the magnetic attractive force generated between the pair of magnet means and the ferromagnetic member.

[0005]

In the conventional lid fastening mechanism using the torque limiting joint means composed of a pair of magnet means, the transmission torque is changed, for example, according to the change of the lid to be closed. If it is necessary to do so, it is necessary to change the interval between the pair of magnet means and / or change the relative position of the magnetic poles of the pair of magnet means, and the changing operation is considerably complicated. In particular, in the case of a lid fastening device equipped with a plurality of lid fastening mechanisms, the spacing between the pair of magnet means is changed in each of the plurality of lid fastening mechanisms and / or the relative magnetic poles of each of the pair of magnet means are changed. It is necessary to change the position,
The change operation requires a considerable amount of time. Similarly, in the conventional lid tightening mechanism using the torque limiting joint means including the pair of magnet means and the ferromagnetic member arranged between the pair of magnet means, when the transmission torque is changed, the pair of magnets is used. It is necessary to change the distance between one or both of the means and the ferromagnetic member and / or change the relative position of the magnetic poles of the pair of magnet means, and the changing operation is considerably complicated.

The present invention has been made in view of the above facts, and its first technical problem is to easily and quickly reduce the transmission torque without performing a complicated operation such as changing the fixing positions of the components. To provide a new and improved closure mechanism.

A second technical object of the present invention is to easily and quickly adjust the transmission torque in a plurality of lid tightening mechanisms provided without performing complicated operations such as changing the fixing positions of the components. To provide a new and improved lid fastening device.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a pair of magnet means arranged facing each other with a gap and a conductive member arranged between the pair of magnet means. By using the torque limiting coupling means configured to generate an eddy current in the conductive member, it is possible to change the transmission torque by simply changing the rotation speed of the input rotating member, and thus simply to rotate the drive source. It was found that the transmission torque can be changed extremely easily by changing the rotation speed of.

That is, according to one aspect of the present invention, as a lid fastening mechanism that achieves the first technical problem, an input rotary member connected to a rotary drive source and an output rotary member connected to a chuck means are provided. And a torque limiting joint means interposed between the input rotating member and the output rotating member, the torque limiting joint means are arranged to face each other with a space therebetween. It is composed of a pair of magnet means and a conductive member arranged between the pair of magnet means. One of the pair of magnet means and the conductive member is fixed to the input member, and the pair of magnet means. The other of the conductive member and the conductive member is fixed to the output member, and when the input rotary member is driven to rotate, an eddy current is generated in the conductive member of the torque limiting joint means, thereby causing the input member to output the output member. Torque limited to Transmission is the lid clamping mechanism is provided, characterized in that.

According to another aspect of the present invention, the rotary support is rotatably mounted, and a plurality of lid fastening mechanisms are mounted on the rotary support at predetermined angular intervals. Each of the individual lid fastening mechanisms includes an input rotary member rotatably mounted on the rotary support, an output rotary member rotatably mounted on the rotary support and having chuck means, and the input rotary member. In a lid fastening device comprising a torque limiting joint means interposed between the output rotating member and the output rotating member, the torque limiting joint means of each of the plurality of lid fastening mechanisms are arranged to face each other with a space therebetween. And a conductive member disposed between the pair of magnet means. One of the pair of magnet means and the conductive member is fixed to the input member. The other of the magnet means and the conductive member is the output When the input rotary member is driven to rotate by being fixed to a member, an eddy current is generated in the conductive member of the torque limiting joint means, thereby transmitting a limited torque from the input member to the output member, A lid fastening device is provided in which the input rotary members of the plurality of lid fastening mechanisms are connected to a common rotary drive source whose output rotation speed is controllable.

Each of the pair of magnet means is formed of a plurality of segment-shaped magnets arranged in a ring shape as a whole, and one of the pair of magnet means has an angle with respect to the input rotary member or the output rotary member. The position is preferably fixed so that it can be adjusted. The conductive member is preferably formed of a ring-shaped copper plate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 illustrates a preferred embodiment of a lid fastening device constructed in accordance with the present invention. The illustrated lid fastening device, generally designated by the reference numeral 2, includes a stationary support shaft 4 extending substantially vertically, and the support shaft 4 is provided with a rotary support through an appropriate bearing means (not shown). 6 is rotatably mounted. The rotary support 6 is connected to a rotary drive source (not shown) which may be an electric motor through an appropriate transmission mechanism (not shown), and is driven to rotate clockwise in FIG. 1 when viewed from above. To be

An annular support plate 10 is fixed to the central portion of the rotary support 6 in the axial direction, and a plurality of mounting openings 12 are formed in the support plate 10 at equal angular intervals. A lid fastening mechanism 14 is attached to each of the mounting openings 12. In FIG. 1, only two mounting openings 12 and two lid fastening mechanisms 14 mounted in the mounting openings 12 are shown. Each of the lid fastening mechanisms 14 includes a shaft member 16 rotatably and vertically movably mounted in the mounting opening 12. An input rotary member 18 is fixed to the lower end of the shaft member 16, and the input rotary member 18 has torque limiting joint means, in the illustrated embodiment, a first torque limiting joint means 20a and a second torque limiting joint means. Two torque limiting coupling means with 20b (Fig. 2
The output rotation member 22 is connected via the. The input rotary member 18, the first torque limiting joint means 20a, the second torque limiting joint means 20b, and the output rotary member 22 will be described in further detail later. An elevating member 23 extending upward is connected to the shaft member 16. The elevating member 23 is revolved, that is, rotated together with the rotary support 6, but is connected rotatably with respect to the shaft member 16 so that the elevating member 23 moves up and down even if the shaft member 16 is rotated as described below. The member 23 does not rotate.
A cam roller 24 is rotatably attached to the upper end of the elevating member 23. A stationary support member 26 is fixed to the support shaft 4, and the annular cam member 2 is attached to the support member 26.
8 is fixed. A cam groove 30 is formed on the outer peripheral surface of the cam member 28, and the cam roller 24 mounted on the elevating member 23 is engaged with the cam groove 30. Therefore, when the rotary support 6 is rotated, the lid fastening mechanism 14 is moved up and down as required according to the locus of the cam groove 30. The lid fastening mechanism 14 shown on the right side in FIG. 1 is located at the uppermost position, and the lid fastening mechanism 14 shown on the left side in FIG. 1 is located at the lowermost position. Chuck means 32 is attached to the output rotary member 20.

Continuing the description with reference to FIG. 1, a stationary support member 34 is fixed to the upper end of the support shaft 4,
A rotary drive source 36, which is conveniently an electric motor capable of arbitrarily controlling the output rotation speed, is mounted on the support member 34. An output gear 38 is fixed to an output shaft that projects below the rotary drive source 36. On the other hand, an input gear 40 is fixed to the shaft member 16 in each of the lid fastening mechanisms 14. And
A transmission member 46 is rotatably mounted on the outer peripheral surface of the rotary support 6 via bearing means 42 and 44, and transmission gears 48 and 50 are fixed to the transmission member 46. The transmission gear 48 is engaged with the output gear 38, and the transmission gear 5
0 is engaged with the input gear 40. Therefore, when the rotary drive source 36 is biased to rotate the output gear 38, each input gear 40 of the lid fastening mechanism 14 is rotated via the transmission gears 48 and 50, and thus the shaft member of the lid fastening mechanism 14 is rotated. 16 is rotated. That is, in the illustrated lid fastening device 2, a plurality of lid fastening mechanisms 14
Shaft member 16 and thus the input rotary member 1 fixed to it
8 are rotationally driven by a single common rotary drive source 36.

An annular support plate 5 is provided below the rotary support 4.
2 and the annular turret plate 54 are also fixed. The annular turret plate 54 is formed with a plurality of receiving notches corresponding to the plurality of lid fastening mechanisms 14, respectively.

In the lid fastening device 2 described above, while the rotary support 6 is continuously rotated, the container 56 filled with the contents is annularly supported at a predetermined angle portion.
Supplied on. The middle portion of the main body of the container, which is supplied in an upright state with the mouth and neck portion facing upward, is received in the receiving cutout of the annular turret plate 54. Next, the lid 58 is fitted on the mouth and neck of the container by an appropriate lid fitting means (not shown). Then, the lid tightening mechanism 14 is lowered, and the chuck means 32 attached to the output rotating member 22 of the lid tightening mechanism 14 is engaged with the lid 58 fitted to the mouth and neck of the container. The lid 58 is rotated with a required torque, and the lid 58 is attached to the male thread formed on the mouth and neck of the container 56.
The female screw formed on the skirt wall is screwed on and the lid 58 is attached to the mouth and neck. Next, the lid fastening mechanism 14 is raised and separated from the lid 58, and the container 56 with the lid 58 mounted and the mouth and neck sealed is discharged from the annular support plate 52. Since the lid fastening operation itself in the illustrated lid fastening device 2 is a form well known to those skilled in the art, a detailed description of the lid fastening operation will be omitted in the present specification.

Next, the input rotary member 18, the first torque limiting joint means 20a, the second torque limiting joint means 20b, and the output rotary member 22 in each of the lid fastening mechanisms 14 will be described with reference to FIG. . In the illustrated embodiment, the input rotary member 18 is composed of a hollow cylindrical casing, and has a circular upper wall 62 and the upper wall 62.
The casing main body 66 has a cylindrical side wall 64 hanging from the peripheral edge of the casing main body 66, and an annular member 68 fixed to the lower end of the casing main body 66 by a fastening screw (not shown). The lower end of the shaft member 16 is connected to the upper end of the kessing main body 66 by an appropriate connecting means (not shown) (the shaft member 16 is not shown in FIG. 2). The output rotary member 22 has a cylindrical shape, the main part of which is inserted into the input rotary member 18 constituting the casing, and three bearing means 70, 72 arranged at intervals in the axial direction. Input rotary member 1 via
It is rotatably attached to 8. The lower end portion of the output rotary member 22 extends downward through an opening formed in the center of the annular member 68, and the chuck means 32 (not shown in FIG. 2) is attached to the lower end portion. Is installed.

A first torque limiting joint 20a and a second torque limiting joint means 20b are arranged between the input rotary member 18 and the output rotary member 22. The first torque limiting joint means 20a is composed of a pair of magnet means 80a and 82a fixed to the input rotary member 18 and a conductive member 84a fixed to the output rotary member 22. Similarly, the second joint means 20b is also composed of a pair of magnet means 80b and 82b fixed to the input rotary member 18 and a conductive member 84b fixed to the output rotary member 22.

More specifically, the magnet means 80a in the first torque limiting joint means 20a has an annular support plate 86a and a plurality of magnet means 80a fixed to the lower surface of the support plate 86a, for example, six.
It is composed of individual permanent magnets 88a. As will be clearly understood by referring to FIG. 3 together with FIG. 2, each of the magnets 88a has a segment shape, and is arranged adjacent to each other in the circumferential direction to form a ring shape as a whole. The surfaces exposed below the adjacent magnets 88a alternately form N poles and S poles. The support plate 86a of the magnet means 80a is fixed to the inner surface of the upper wall 62 of the casing main body 64 constituting the input rotary member 18 by a fastening screw (not shown). An annular adjusting member 90 is provided at an axially intermediate portion in the casing body 64, and the magnet means 82a in the first torque limiting joint means 20a is attached to the adjusting member 90 by a fastening screw (not shown). It is composed of a plurality of, for example, six permanent magnets 92a fixed to the upper surface. Each of the magnets 92a is also segment-shaped,
They are arranged adjacent to each other in the circumferential direction and form an annular shape as a whole.
The surfaces exposed above the adjacent magnets 92a alternately form N poles and S poles. The adjusting member 90 is rotatably arranged about the central axis in the casing body 64, and a set screw 98 is screwed to the adjusting member 90 through a circumferentially extending arcuate slit 96 formed in the side wall 62 of the casing body 64. By tightening it, it can be fixed at the required angular position. In other words, by loosening the setscrew 98, the angular position of the adjusting member 90 can be adjusted appropriately. As will be clearly understood by referring to FIG. 2, the magnet means 80a and the magnet means 82a are positioned axially spaced apart from each other.

The conductive member 84a of the first torque limiting joint means 20a has an annular shape and is fixed to the upper outer peripheral surface of the output rotary member 22. It is important that the conductive member 84a is made of a highly conductive material, and a suitable material is copper. As can be seen by referring to FIG. 2, the conductive member 84a is positioned between the pair of magnet means 80a and 82a, and the conductive member 84a
There is a slight gap between the upper surface of a and the lower surface of the magnet member 80a, and the lower surface of the conductive member 84a and the magnet means 82a.
There is also a small gap between it and the upper surface of.

The magnet means 80b of the second torque limiting joint means 20b includes an annular support plate 86b and this support plate 86b.
A plurality of permanent magnets 88 fixed to the upper surface of the
b and. Each of the magnets 88b has a segment shape and is arranged adjacent to each other in the circumferential direction to form an annular shape as a whole. The surfaces exposed above the adjacent magnets 88b alternately form N poles and S poles. Magnet means 8
The support plate 86b of 0b is fixed to the inner surface of the annular member 68 forming the input rotary member 18 by a fastening screw (not shown). The magnet means 82b in the second torque limiting joint means 20b is composed of a plurality of permanent magnets 92b, for example, six permanent magnets 92b fixed to the lower surface of the adjusting member 90 by fastening screws (not shown). Each of the magnets 92b also has a segment shape, is arranged adjacent to each other in the circumferential direction, and has an annular shape as a whole. Adjacent magnet 9
The surface exposed below 2b alternates between north pole and south pole.
Form a pole. As will be clearly understood with reference to FIG. 2, both the magnet means 80b and the magnet means 82b are positioned axially spaced apart from each other.

The conductive member 84b of the second torque limiting joint means 20b is also ring-shaped and is fixed to the lower outer peripheral surface of the output rotary member 22. As will be understood by referring to FIG. 2, the conductive member 84b includes a pair of magnet means 8a.
0b and 82b, there is a slight gap between the upper surface of the conductive member 84b and the lower surface of the magnet member 82b, and there is also a slight gap between the lower surface of the conductive member 84b and the upper surface of the magnet means 80b. There is a gap.

In the lid fastening device 2 as described above,
When the rotary drive source 36 is urged to rotate each shaft member 16 of the lid fastening mechanism 14 and the input rotary member 18 fixed thereto, for example, in the clockwise direction when viewed from above in FIGS. 1 and 2. In the first torque limiting joint means 20a and the second torque limiting joint means 20b, the magnet means 80a and 82a and 80b and 82b fixed to the input rotary member 18 are rotated. Thus, the conductive members 84a and 84b are relatively rotated in the magnetic field formed by the pair of magnet means 80a and 82a and the magnetic field formed by the pair of magnet means 80b and 82b, respectively. Eddy currents are generated in the conductive members 84a and 84b. Then, a magnetic field is generated by the eddy current, and thus the pair of magnet means 80a and 82a.
And a conductive member 84a, and a magnetic attraction force is generated between the pair of magnet means 80b and 82b and the conductive member 84b, and the magnetic attraction force causes the conductive members 84a and 84b.
b is also rotated, and thus the output rotary member 22 is also rotated.

According to experiments conducted by the present inventors, the first torque limiting joint means 20a and the second torque limiting joint means 20 are
The maximum torque transmitted from the input rotary member 18 to the output rotary member 22 via b is a pair of magnet means 80a and 80a.
2a and the magnetic field strength formed by the pair of magnet means 80a and 82a, therefore the relative positional relationship between the N or S pole of the magnet means 80a and the S pole or N pole of the magnet 82a, and the N of the magnet means 80b. It is changed by the relative positional relationship between the pole or S pole and the S pole or N pole of the magnet 82b, and also changed by the rotation speed of the input rotary member 18. Figure 4
Magnet means 80a and 82a and magnet means 80b and 82b
The fluctuation of the maximum transmission torque due to the relative position with respect to the input rotary member 18, that is, the torque applied to the output rotary member 22 is gradually increased and the torque of the output rotary member 22 starts to slip with respect to the input rotary member 18, FIG. 6 is a diagram showing a tendency of fluctuations in maximum transmission torque depending on the rotation speed of.
4, the horizontal axis represents the rotation speed of the input rotary member 18, the vertical axis represents the maximum transmission torque, and the ● line represents the magnets 80a and 82.
When the angular position of the N pole at a is aligned with the angular position of the S pole at the magnets 80b and 82b, the ▲ line indicates that the adjustment member 90 is rotated by 20 degrees in the predetermined direction from the state of the ● line, and the ■ line indicates the adjustment. When the member 90 is further rotated by 20 degrees in the predetermined direction, the x-line indicates that the adjusting member 90 is further rotated by 20 degrees in the predetermined direction and the angular position of the N pole of the magnets 80a and 82a and the angle of the N pole of the magnets 80b and 82b. The relationship between the rotational speed of the input rotary member 18 and the maximum transmission torque when the positions are aligned is shown. As can be seen from FIG.
The maximum transmission torque is increased as the rotation speed of the input rotary member 18 is increased, and also the maximum transmission torque is increased as the magnetic field formed by the pair of magnet means 80a and 82a and the magnetic field formed by the pair of magnet means 80b and 82b become stronger. The torque is increased.

Referring to FIG. 4, in the lid fastening device 2 constructed according to the present invention, it is desired to change the maximum transmission torque, that is, the torque applied to the lid 58, in accordance with the change of the form of the lid 58. In this case, it is possible to change all the maximum transmission torques of the plurality of lid fastening mechanisms 14 by simply changing the output rotation speed of the rotary drive source 36.
If it is desired to change the value of the maximum transmission torque of the lid fastening mechanism 14 in a considerably large amount, the angular position of the adjusting member 90 may be changed in each of the lid fastening mechanisms 14.

[0027]

In the lid tightening mechanism of the present invention, the transmission torque can be easily and easily changed by changing the rotational speed of the input rotary member without performing a complicated operation such as changing the fixed position of the component. Can be changed quickly.

Further, in the lid fastening device of the present invention, the transmission torques of the plurality of lid fastening mechanisms provided are simply rotated in common without performing complicated operations such as changing the fixing positions of the components. By changing the output rotation speed of the drive source, it can be changed easily and quickly.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view showing a preferred embodiment of a lid fastening device configured according to the present invention.

FIG. 2 is a cross-sectional view showing a main part of a lid fastening mechanism in the lid fastening device of FIG.

FIG. 3 is a bottom view showing a magnet unit used in the lid fastening mechanism of FIG.

FIG. 4 shows the maximum transmission torque of the lid fastening mechanism of FIG.
FIG. 6 is a diagram showing a variation due to a rotation speed of an input rotary member and a variation due to rotation of an adjustment plate (thus, variation in magnetic field strength generated by a magnet pair).

[Explanation of symbols]

2: Lid tightening device 6: Rotating support 14: Lid tightening mechanism 18: Input rotating member 20a: torque limiting joint means 20b: torque limiting joint means 22: Output rotating member 32: Chuck means 36: Common rotation drive source 56: Container 58: Lid 80a: magnet means 80b: magnet means 82a: magnet means 82b: magnet means 84a: conductive member 84b: conductive member 90: Adjusting member

Claims (6)

[Claims] 1. An input rotary member connected to a rotary drive source, an output rotary member having a chuck means, and torque limiting joint means interposed between the input rotary member and the output rotary member. In the lid tightening mechanism, the torque limiting joint means is composed of a pair of magnet means arranged to face each other with a gap and a conductive member arranged between the pair of magnet means. One of the pair of magnet means and the conductive member is fixed to the input member, the other of the pair of magnet means and the conductive member is fixed to the output member, and when the input rotary member is driven to rotate, An eddy current is generated in the conductive member of the torque limiting joint means, whereby the limited torque is transmitted from the input member to the output member. 2. Each of the pair of magnet means is formed of a plurality of segment-shaped magnets arranged in a ring shape as a whole, and one of the pair of magnet means has one of the input rotary member or the output rotary member. The lid tightening mechanism according to claim 1, wherein the lid tightening mechanism is fixed to the so as to be adjustable in angular position. 3. The lid fastening mechanism according to claim 1, wherein the conductive member is formed of a ring-shaped copper plate. 4. A rotatably mounted rotary support, and a plurality of lid fastening mechanisms mounted on the rotary support at predetermined angular intervals, each of the plurality of lid fastening mechanisms being provided. An input rotary member rotatably mounted on the rotary support, an output rotary member rotatably mounted on the rotary support and having chuck means, and between the input rotary member and the output rotary member A lid tightening device comprising intervening torque limiting joint means, wherein the torque limiting joint means of each of the plurality of lid fastening mechanisms includes a pair of magnet means arranged facing each other with a space therebetween. A pair of magnet means and a conductive member disposed between the pair of magnet means, one of the pair of magnet means and the conductive member being fixed to the input member, and the pair of magnet means and the conductive member. And the other of the input members is fixed to the output member. When the member is driven to rotate, an eddy current is generated in the conductive member of the torque limiting joint means, thereby transmitting a limited torque from the input member to the output member, and the eddy current of the plurality of lid tightening mechanisms is transmitted. The input rotary member is connected to a common rotary drive source whose output rotary speed is controllable,
A lid fastening device characterized by the above. 5. Each of the pair of magnet means in each of the plurality of lid fastening mechanisms is formed of a plurality of segment-shaped magnets arranged in a ring shape as a whole, and one of the pair of magnet means is provided. The lid fastening device according to claim 4, wherein is fixed to the input rotary member or the output rotary member so that the angular position can be adjusted. 6. The lid fastening device according to claim 4, wherein the conductive member is formed of a ring-shaped copper plate.