JPH0356894Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a recording/reproducing apparatus, and more particularly to a recording/reproducing apparatus equipped with a rotating head cylinder in which a tape can be slidably contacted.

[Background of the idea]

Conventionally, recording and reproducing apparatuses to which a tape cassette is attached record and reproduce tapes using analog signals. By the way, recently, from the viewpoint of downsizing of tape cassettes and high-density recording, DAT (Digital Audio Tape)
2. Description of the Related Art There has begun to be a desire to record and play back audio using digital signals, and research and development efforts are underway in various places to meet this demand. However, despite such demands, a desirable recording/playback device for DAT has not yet been proposed.

[Purpose of invention]

The present invention has been made in view of the actual situation in the prior art, and its purpose is to provide a recording/playback device that can record and play back audio using digital signals.

[Summary of the idea]

To achieve this objective, the present invention includes a rotating head cylinder on which the tape in the tape cassette can slide, and a rotating head cylinder in the direction approaching the rotating head cylinder.
and a pair of moving bodies that move the tape in a direction away from the rotating head cylinder, a pair of connecting members each having one end relatively rotatably connected to each of these moving bodies, and the other connecting members. 1 in which each of the ends is connected so as to be rotatable relative to each other;
a first connecting plate rotatably connected to the movable body; and a second connecting plate rotatably connected to the rotating body. , a guide means for guiding these first and second connecting plates in the direction in which their respective rotational supports come into contact with and separate from each other, and these first and second connecting plates
The structure includes a spring that is stretched between the connecting plates of and biases the respective pivot points in a direction away from each other.

[Example of idea]

Hereinafter, embodiments of the present invention will be described based on the drawings.

Figures 1 to 4 are explanatory diagrams showing an embodiment of the present invention. Figure 1 is a plan view of the main parts showing the state before tape loading starts, and Figure 2 shows the state before tape loading starts. FIG. 3 is a plan view of the main part showing the state at the end of tape loading, and FIG. 4 is an exploded perspective view showing the connecting member provided in this embodiment. .

In these figures, especially in FIG. 1, 1 is a chassis, and 2 is a rotary head cylinder attached to this chassis 1. In FIG. Although not shown, the rotary head cylinder 2 consists of a rotatable upper part on which a magnetic head is attached, and a non-rotatable lower part, and the lower part is fixed to the chassis 1. Reference numerals 3 and 4 denote a pair of linear guide holes which are provided in the chassis 1, for example, and form an inverted V shape so as to sandwich the rotary head cylinder 2 therebetween, and stoppers 5 and 6 are disposed at the tips of the guide holes. These stoppers 5, 6 are fixed to the chassis 1, for example, by screws. 7 indicated by a two-dot chain line is a tape cassette, and inside this tape cassette 7 is a digital audio tape 7.
a is stored. 7b is a notch formed in the tape cassette 7. Tips 3a, 4 of guide holes 3, 4 where the aforementioned stoppers 5, 6 are located
For example, as shown in FIG. 1, point a is positioned slightly beyond an imaginary line 8 passing through the diameter of the rotary head cylinder 2, which is parallel to the tip end 7c of the tape cassette 7 mounted thereon. In addition, 9 and 10 shown by two-dot chain lines are elongated holes formed in the chassis 1, respectively.
Reference numerals 11 and 12 indicate a supply reel for supplying the tape 7a in the tape cassette 7, and a take-up reel for winding up the tape 7a.

Moving bodies 13 and 14 are movable along the guide holes 3 and 4, respectively, and move the tape 7a in the tape cassette 7 toward and away from the rotary head cylinder 2. Mobile object 1
3 is a base 13a disposed on the chassis 1, for example.
It is formed by a shaft 13b attached to the base 13a, a guide post 13c fixed above the base 13a and guiding the tape 7a, and an inclined post 13d. As shown in FIG. 2, a protrusion 13e that is movably engaged with the guide hole 3 is formed on the back side of the base 13a, and the shaft 13b is movably engaged with the guide hole 3. It has a small diameter portion 13f and a large diameter portion 13g connected below the small diameter portion 13f. Similarly, moving object 1
4 also includes, for example, a base 14a having a protrusion 14e, and a shaft 14b having a small diameter part 14f and a large diameter part 14g.
, a guide post 14c, and an inclined post 14d.

Reference numerals 15 and 16 are connection members whose one ends are connected to the movable bodies 13 and 14, respectively, so that they can rotate relative to each other. As shown in FIG. 4, the connecting member 15 includes a connecting plate 15a rotatably connected to the shaft 13b of the movable body 13, and a connecting plate 15a disposed on the connecting plate 15a. a connecting plate 15b that is slidable relative to the connecting plate 15b, and these connecting plates 15a, 1
Spring 15c stretched between 5b and connecting plate 1
It is formed by a shaft 15d that connects the other ends of 5a and 15b. And connecting plates 15a, 15b
U-shaped bent portions 15e and 15f are formed on the body, and a shaft 13 is formed on one end of the connecting plate 15b.
A long hole 15g is formed in which the neck 13h connected to the lower part of the large diameter part 13g of b is engaged in a relatively movable manner, and the shaft 15d is formed in the small diameter part 15h and below the small diameter part 15h. The connecting plate 15a has a large diameter portion 15i formed under the large diameter portion 15i, and a neck portion 15j formed below the large diameter portion 15i.
An elongated hole 15k is formed into which the neck 15j of d is relatively movable.

Further, as shown in FIGS. 2 and 3, the connecting member 16 includes a connecting plate 16a that is rotatably connected to the shaft 14b of the movable body 14, and is arranged on the connecting plate 16a, and is arranged on the connecting plate 16a. A connecting plate 16b that is slidable relative to the plate 16a, and these connecting plates 16a, 1
Spring 16c stretched between 6b and connecting plate 16
a and a shaft 16d connecting the other ends of 16b. In addition, the connecting plate 16a and the connecting plate 1
6b is formed in a straight line shape as a whole, and although not particularly shown, there is a connecting plate 1 connected to the shaft 14b.
An elongated hole is formed in one end of the connecting plate 16b, and the shaft 14b is engaged in a relatively movable manner, and the other end of the connecting plate 16a connected to the shaft 16d is connected to the shaft 16d.
An elongated hole 16e is formed through which the two parts are relatively movable.

Further, 17 is a rotating body to which the other ends of the connecting members 15 and 16 are connected so as to be rotatable relative to each other. , and a small-diameter gear 17b provided coaxially, and a substrate 1 that is integrally attached to the gear 17a and has approximately the same shape as the gear 17a.
7c, a shaft 15d of the connecting member 15 is connected to the back surface of the substrate 17c so as to be relatively rotatable, and a projecting portion 17d on the front surface of the substrate 17c.
A shaft 16d of the connecting member 16 is connected to the connecting member 16 so as to be relatively rotatable. Note that the connecting member 16 is a gear 17
It is arranged at a height position where it can interfere with the notch 17e of a. Reference numeral 18 denotes a support shaft that forms the center of rotation of the rotating body 17 and is supported by the chassis 1, for example.

The rotating body 17 is moved from the state shown in FIG.
Until the state shown in the figure, that is, the axis 1 of the connecting member 15
5d crosses the imaginary line 18a connecting the spindle 18 of the rotating body 17 and the axis 13b of the movable body 13 shown in FIG. 3, and the shaft 16d of the connecting member 16 moves with the spindle 18 shown in FIG. It is set to rotate until it crosses an imaginary line 18b connecting the axis 14b of the body 14. Further, when the connecting member 15 is closest to the support shaft 18 of the rotating body 17 as shown in FIG. They face each other to the extent that they do not touch each other, that is, the bent portions 15e, 1
5f constitutes an interference prevention portion that prevents interference with the support shaft 18.

19, 20, 21 are gears, of which gear 19
has a small diameter gear part 19a that engages with the gear 17a of the rotating body 17, and a large diameter gear part 19b located above the small diameter gear part 19, and the gear 20 has a small diameter gear part 19b that engages with the large diameter gear part 19b. A gear section 20a and a large diameter gear section 20 located below the small diameter gear section 20a.
b, and the gear 21 engages with the large diameter gear portion 20b. 22 is a motor that rotates the gear 21.

Reference numeral 23 denotes a lug that engages with the small-diameter gear 17b of the rotating body 17, and has one end connected to the elongated hole 9 of the chassis 1 described above.
It has a shaft 23a that movably engages with the elongated hole 10, and a shaft 23b that movably engages with the elongated hole 10 at the other end. 24 is a capstan shaft, 25 is a pinch roller that can come into contact with this capstan shaft 24, 26 is an arm that supports the pinch roller 25,
A shaft 27 rotatably supports the arm 26, and is fixed to the chassis 1, for example. A spring 28 has one end attached to the shaft 23a of the rack 23 mentioned above, and the other end attached to a pin 27a provided on the protruding portion of the arm 26, urging the arm 26 in a direction approaching the shaft 23a. There is. In addition, 29 is chassis 1
This is a stopper pin that is provided in the connecting member 16 and restricts the movement of the connecting member 16 described above. Rack 23 mentioned above,
A pinch roller driving means for rotating the pinch roller 25 in a direction toward the capstan shaft 24 and in a direction away from the capstan shaft 24 is constituted by a spring 28, an arm 26, a shaft 27, and the like.

Further, the springs 15 of the above-mentioned connecting members 15 and 16
In the state shown in FIG. 3, the forces c and 16c act as forces to rotate the rotating body 17 counterclockwise via the connecting members 15 and 16, and also act as a force to rotate the rotary body 17 in the counterclockwise direction, and also engage the arm 26 of the pinch roller 25. The force of the spring 28 acts as a force to rotate the rotating body 17 clockwise via the rack 23, but the force of the spring 15c, 1
The forces of these springs 15c, 16c, and 28 are set so that the rotational force of the rotating body 17 caused by the spring 6c is larger than the rotational force of the rotating body 17 caused by the spring 28.

Note that although the attachment/detachment mechanism for the tape cassette 7 and the drive mechanism for the reels 11 and 12 are not shown, these mechanisms can be constructed by reusing, for example, a mechanism provided in a known analog recording/playback device. It can be configured as follows.

Next, the operation of the embodiment configured as described above will be explained.

As shown in FIGS. 1 and 2, when the tape cassette 7 is engaged with the reels 11 and 12 before tape loading starts, the movable bodies 13 and 14 are moved to the guide holes farthest from the stoppers 5 and 6. The guide posts 13c, 14c and the inclined posts 13d, 14d are housed in the tape cassette 7, respectively. The tape 7a can be engaged with the tape 7a. Furthermore, the pinch roller 25 is also located within the notch 7b of the tape cassette 7, so that the pinch roller 25 can move the tape 7a
It is now possible to engage with the

Also, the notch 17e of the rotating body 17 and the connecting member 16 are in a state of interference, and the bent portions 15e, 15f of the connecting plates 15a, 15b of the connecting member 15 are prevented from interfering with the support shaft 18 of the rotating body 17. is facing. At this time, the connecting member 15 is moved by the force of the spring 15c to the shaft 13b of the movable body 13 shown in FIG.
is located at the outermost end of the long hole 15g of the connecting plate 15b,
The shaft 15d is located at the outermost end of the elongated hole 15k of the connecting plate 15a, that is, the shaft 13b and the shaft 15d are the most distant from each other. Similarly, the coupling member 16 is configured such that the shafts 14b and 16d of the movable body 14 are farthest from each other due to the force of the spring 16c.

Further, the rack 23 is positioned such that the shafts 23a and 23b respectively engage with the end portions of the elongated holes 9 and 10 formed in the chassis 1, and accordingly, the arm 26 or The pinch roller 25 is located farthest from the capstan shaft 24.

In this state, when the motor 22 is driven, the gear 21 rotates, and the gear 2
0 and 19 rotate, and the semicircular gear 17a, the small diameter gear 17b, and the base plate 17c, that is, the rotating body 17, rotate in the direction of the arrow 30 in FIG. 17, the connecting members 15, 16 and the rack 23 move.

Then, as the connecting members 15 and 16 move,
As the movable bodies 13 and 14 move while the protrusions 13e and 14e of the bases 13a and 14a and the small diameter portions 13f and 14f of the shafts 13b and 14b are guided by the guide holes 3 and 4, as shown in FIG. It moves in the directions of arrows 31 and 32 in FIG. 1 along the guide holes 3 and 4 while maintaining its shape, that is, without rotating. With this, the guide post 13c, 1
4c, the inclined posts 13d and 14d engage the tape 7a, and the tape 7a is pulled out from the tape cassette 7.

Then, when the rotating body 17 continues to rotate, the movable bodies 13 and 14 come into contact with the stoppers 5 and 6 to stop their movement, and the shaft 1 of the rotating body 17
8, the shaft 15d of the connecting member 15, and 13 of the moving body 13.
b are aligned on the imaginary line 18a shown in FIG. 3, and the axis 18 of the rotating body 17, the axis 16d of the connecting member 16, and the axis 14b of the movable body 14 are aligned on the imaginary line 18a shown in FIG. 18b, and when the rotating body 17 rotates further, the shaft 15
d and 16d exceed the imaginary lines 18a and 18b, and the connecting member 16 comes into contact with the stopper pin 29. For example, a switch (not shown) detects that the connecting member 16 has come into contact with the stopper pin 29, and in response to the signal, a drive stop signal is output from the control device (not shown) to the motor 22, whereby the drive of the motor 22 is stopped. The rotating body 17 stops rotating, and the third
The state shown in the figure is reached.

Note that the springs 15c,
16c, the shaft 13b passes through the elongated hole 15g of the connecting plate 15b, and the shaft 15d passes through the elongated hole 1 of the connecting plate 15a.
5k, the shaft 14b goes inside the long hole (not shown) of the connecting plate 16b, and the shaft 16d goes inside the long hole 16e of the connecting plate 16a.
The connection plates 15a, 1
5b, 16a, and 16b slide relative to each other. Further, the rotating body 17 is placed in the state shown in FIG.
When the motor 22 stops, the forces of the springs 15c and 16c of the connecting members 15 and 16 act on the rotating body 17 via the connecting members 15 and 16, thereby stopping the driving of the motor 22. Nevertheless, the rotating body 17 moves in the counterclockwise direction, that is, arrow 3 in FIG.
Rotational force is applied in four directions.

On the other hand, as the rotating body 17 is rotated in the direction of the arrow 30 shown in FIG.
a, 23b are guided by the elongated holes 9, 10 and move in the direction of arrow 33 in FIG.
a, spring 28, arm 26 via pin 27a,
That is, the pinch roller 25 corresponds to the arrow 33 in FIG.
Rotate in direction a. Then, the rotating body 17
As it rotates, the arm 26 rotates and the pinch roller 25 comes into contact with the capstan shaft 24 with the tape 7a in between, and when the rotating body 17 further rotates, the shafts 23a and 23b of the rack 23 move into the elongated hole 9. ，
10 reaches the tip. At this time, pinch roller 2
5 is locked to the capstan shaft 24, but the spring 28 stretches as the shaft 23a moves, and the force of the spring 28 presses the pinch roller 25 well against the capstan shaft 24. Then, the tape 7a is held between the capstan shaft 24 and the pinch roller 25. At this time, the force of the spring 28 acts on the rotating body 17 via the shaft 23a and the rack 23, thereby imparting a rotational force to the rotating body 17 in the direction of arrow 35 in FIG. 3. However, in the state at the end of loading shown in FIG.
So that the rotational force due to force 6c is greater,
Since the forces of these springs 28, 15c, and 16c are set, at this time, the rotating body 17 is
A rotational force corresponding to the difference between the rotational force due to the force of the spring 28 and the rotational force due to the force of the spring 28 is applied in the direction of the arrow 34 shown in FIG.

In this way, the loading state shown in FIG. 3 is reached, and the tape 7a is circumferentially attached to the rotary head cylinder 2 so that the wrapping angle is approximately 90 degrees. Then, by driving a reel driving means (not shown) and rotating the rotary head cylinder 2, the tape 7a runs while sliding on the rotary head cylinder 2, and is wound on the take-up reel 12 to record the desired audio. You can perform playback operations.

Note that the loading release operation can be performed in the exact opposite order to the above procedure. That is, the motor 22 is rotated in the opposite direction to the above, and the gears 21, 20, 1
9 in the direction of arrow 35 in FIG. Mobile object 1
3 and 14 are guided by the guide holes 3 and 4 and move as shown by arrows 36 and 37 in FIG.
When b and 14b are engaged with the ends of the elongated holes 9 and 10, the movement is stopped and the state shown in FIG. 1 is achieved. After the movable bodies 13 and 14 stop moving, the motor 22 stops rotating.

In the embodiment configured in this way, the movable bodies 13 and 14 are moved in the direction approaching the rotary head cylinder 2 by the rotary body 17 and the connecting members 15 and 16 connected to the rotary body 17. Since the tape 7a in the tape cassette 7 can be reliably brought into sliding contact with the rotary head cylinder 2, it is possible to record and reproduce audio using digital signals.

Furthermore, the connection member 1 is connected by one rotating body 17.
Since the movable bodies 13 and 14 are moved together via the movable parts 5 and 16, the loading mechanism is simple, the number of parts can be reduced, and manufacturing costs can be reduced.

Moreover, by one rotating body 17, the movable body 13,
Since both of the movable bodies 13 and 14 are moved, there is no variation in the amount of movement between the movable bodies 13 and 14.

Further, a notch 17e is formed in the rotating body 17,
Connecting member 1 connecting rotating body 17 and moving body 14
6 is arranged so as to be able to interfere with the notch portion 17e, the overall shape of the rotating body 17 can be made small, and the space for arranging the connecting member 16 can be small.

In addition, the cutout portion 17 of the rotating body 17 may be opened before loading starts or after loading is canceled.
e and the connecting member 16, so that the notch 17 can be made to interfere with the connecting member 16 before the loading starts or after the loading is finished.
e and the connecting member 16 act as a stopper to restrict the rotation of the rotating body 17, that is, the clockwise rotation in FIG. can do.

Further, the connecting members 15 and 16 are relatively slidable connecting plates 15a and 15b, and a connecting plate 16, respectively.
a, 16b, these connecting plates 15a and connecting plate 1
5b, and springs 15c and 16c stretched between the connecting plate 16a and the connecting plate 16b, the positions of the shafts 13b and 14b of the movable bodies 13 and 14 at the end of loading and , the change in the distance between the connecting members 15, 16 and the shafts 15d, 16d, which are the connecting parts of the rotating body 17, that is, the overstroke, is controlled by the connecting plates 15a, 15b.
It can be well absorbed by the sliding action performed between the connecting plates 16a and 16b.

Further, the connecting plates 15a and 15b of the connecting member 15 connected to the rotating body 17 are provided with U-shaped bent portions 15e and 15f that prevent interference with the support shaft 18 that forms the center of rotation of the rotating body 17, that is, interference. Since the structure includes the prevention portion, the length of the support shaft 18 of the rotating body 17 can be set to be sufficiently large.

In addition, the rotation operation of the rotating body 17 is controlled by the pinch roller 2.
5, a rack 23, a spring 28, an arm 26,
It is equipped with a pinch roller driving means consisting of a shaft 27, etc., and the connecting members 15 and 16 are connected to the connecting plates 15a,
15b, 16a, 16b and these connecting plates 15
a, 15b, 16a, 16b, and has springs 15c, 16c stretched between the springs 15c, 16c, and a rotational force applied to the rotating body 17 via the connecting members 15, 16 when the movable bodies 13, 14 stop due to the end of loading. The forces of the springs 15c and 16c are set so that the force is larger than the rotational force applied to the rotating body 17 via the pinch roller drive member when the pinch roller 25 is pressed against the capstan shaft 24. Therefore, it is possible to lock the rotating body 17 so that it does not rotate in the direction of arrow 35 in FIG. 3 without providing any special locking means. Although not shown, it is also possible to provide means for rotating only the pinch roller 25 away from the capstan shaft 24 from the state shown in FIG. It is also possible to ensure a sufficient rotational force and rotate the pinch roller 25 while keeping the rotating body 17 stationary. In this case, the review and queue modes can be easily realized. I can do it.

In the above embodiment, the connecting member 16 can interfere with the notch 17e of the rotating body 17 and serves as a stopper, but the present invention is not limited to this, and the connecting member 16 can interfere with the notch 17e of the rotating body 17. By appropriately setting the shape of the connecting member 17e, the connecting member 15 can be made to interfere with the rotating body 17 as a stopper for preventing rotation, or both connecting members 15 and 16 can be made to be able to interfere with the rotating body 17 as a stopper. You can make it happen.

Further, in the above embodiment, both of the connecting members 15 and 16 are connected to the two connecting plates 15a and 15b and the spring 15.
c, or two connecting plates 16a, 16b and a spring 16c, but the present invention is not limited to this, and one of the connecting members 15, 16 may be formed by one connecting plate without a spring. It can also be configured as follows.

Further, in the above embodiment, the interference prevention portions, that is, the bent portions 15e and 1 that prevent interference with the support shaft 18 of the rotating body 17 on the connecting plates 15a and 15b of the connecting member 15,
5f, but depending on the form of the rotating body 17, the connecting member 16 may be provided with an interference prevention part that prevents interference with the support shaft 18, and the connecting members 15, 1
6 may be provided with an interference prevention portion that prevents interference with the support shaft 18. Note that the interference prevention section is the first,
In addition to the U-shaped configuration shown in Figures 3 and 4, when changing the location of the rotating body 17 from the position shown in Figure 2, for example, the support shaft 1
It may be formed into a circular arc shape such that it is disposed above 8.

Further, in the above embodiment, the guide holes 3 and 4 are formed in the chassis 1 to move the movable bodies 13 and 14, but the form of the movable bodies 13 and 14 and the engagement form of the guide holes 3 and 4 are For example, apart from the chassis 1, a sub-chassis is provided opposite to the chassis 1 and above the chassis 1, one guide hole 3 is formed in the chassis 1, and the other guide hole 3 is formed in the chassis 1. Two guide holes 4 may be formed in the sub-chassis.

[Effect of idea]

As mentioned above, the recording and playback device of the present invention has 1
The tape cassette is configured to move the tape in the tape cassette toward the rotary head cylinder or away from the rotary head cylinder by means of two rotating bodies and a pair of connecting members connected to the rotary bodies. , the tape can be reliably brought into sliding contact with the rotating head cylinder, or can be reliably removed from the rotating head cylinder,
Recording and playback of audio using digital signals can be realized.

In addition, since the pair of moving bodies to which the tape is engaged is moved by one rotating body, there is no variation in the amount of movement between the moving bodies, and the movement is stable at all times. can be performed.

Further, at least one of the connecting members includes a first connecting plate rotatably connected to the moving body, a second connecting plate rotatably connected to the rotating body, and a first connecting plate and a second connecting plate rotatably connected to the rotating body. a guide means for guiding the connecting plate in a direction in which each pivot point approaches and separates;
and a spring that is stretched between the second connecting plate and biases the respective rotational fulcrums in a direction away from each other, so that the position of the moving body after loading, the position of the connecting member and the rotating body Changes in the distance between the position of the connecting part and the position of the connecting part, that is, overstroke, can be well absorbed by the sliding movement carried out between the two connecting plates, and therefore,
Stable loading performance can be obtained.

[Brief explanation of the drawing]

Figures 1 to 4 are explanatory diagrams showing one embodiment of the recording/playback device of the present invention. Figure 1 is a plan view of the main part showing the state before tape loading starts, and Figure 2 is a plan view of the main part showing the state before tape loading starts. FIG. 3 is a plan view of the main parts showing the state at the end of tape loading, and FIG. 4 is an exploded view showing the connecting members provided in this embodiment. FIG. 1... Chassis, 2... Rotating head cylinder,
3, 4...Guide hole, 7...Tape cassette, 7a
... Tape, 9, 10 ... Long hole, 13, 14 ...
Mobile body, 13a, 14a...base, 13b, 14
b...Shaft, 13c, 14c...Guide post, 1
3d, 14d...slanted post, 13e, 14e...
...Protrusion, 15, 16...Connecting member, 15a, 15
b, 16a, 16b...Connecting plate, 15c, 16c
...Spring, 15d, 16d...Shaft, 15e, 15
f...Bending portion, 15g, 15k, 16e...Elongated hole, 17...Rotating body, 17a, 17b...Gear,
17c...Substrate, 17e...Notch, 18...
Support shaft, 19, 20, 21...Gear, 22...Motor, 23...Rack, 23a, 23b...Shaft, 2
4...Capstan shaft, 25...Pinch roller, 26...Arm, 27...Shaft, 27a...
Pin, 28...Spring, 29...Stoppin.

Claims (1)

[Scope of utility model registration request] a rotating head cylinder on which a tape in a tape cassette can slide; a pair of moving bodies for moving the tape in a direction toward the rotating head cylinder and in a direction away from the rotating head cylinder;
A pair of connecting members having one end relatively rotatably connected to each of these moving bodies, and one rotating body having each of the other ends of these connecting members relatively rotatably connected. and at least one of the connecting members includes a first connecting plate rotatably connected to the moving body, a second connecting plate rotatably connected to the rotating body, and a first connecting plate rotatably connected to the rotating body; a guide means for guiding the first and second connecting plates in a direction in which their respective rotational fulcrums approach and separate;
and a spring stretched between the second connecting plates and biased in a direction away from each pivot point.