JPS6034128Y2 - Reel shaft mechanism of magnetic recording tape traveling device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a reel shaft mechanism which is installed in a magnetic recording tape running device, has a reel hub around which a magnetic recording tape is wound, and is driven and rotated by a rotational force supply means provided in a chassis. .

Most conventional magnetic recording tape running devices, particularly tape recorders, use DC motors as rotational force supply means.

There are two types of DC motors: unidirectional DC motors that rotate only in one direction, and bidirectional DC motors that can rotate in one direction and the other direction with the same characteristics without any failure.

However, most of the conventional magnetic recording tape running devices have been unidirectional DC motors.

This is because unidirectional DC motors are cheaper, and in conventional bidirectional DC motors, there is a slight difference between the characteristics in one direction and the characteristics in the other direction. This is because the above-mentioned slight difference in characteristics was outside the permissible range of the tape recorder, which is required to rotate the capstan and reel shaft with the same characteristics in one direction and the other direction.

Among conventional magnetic recording tape running devices, in particular tape recorders that are compact and have one pair of reel shaft mechanisms and at least one capstan, the pair of reel shaft mechanisms described above are used to save space. The at least one capstan is driven by one unidirectional DC motor.

Therefore, a single unidirectional DC motor is used to operate the pair of reel shaft mechanisms and the at least one capstan for various operations such as constant speed feeding, fast winding, and stopping of the magnetic recording tape. In order to achieve this rotation, conventional tape recorders use a mechanical operation switching mechanism to transmit rotational force between the one DC electric motor, the pair of reel shaft mechanisms, and the at least one capstan. This is done by an idler that is operated.

However, since the idler is operated by a mechanical operation switching mechanism, there is a drawback that not only does it take a relatively long time to change each operation amount described above, but also a relatively large force is required.

Furthermore, it is necessary to secure a space for the operation switching mechanism and a space for the idler to move, which is an obstacle to further downsizing the tape recorder.

Furthermore, the provision of an operation switching mechanism and an idler complicates the structure and increases manufacturing costs.

By the way, the performance of recent bidirectional DC motors has improved, so the difference between the characteristics in one direction and the characteristics in the other direction has been largely eliminated, and even if the above difference occurs, It is within the allowable range of the tape recorder.

Furthermore, the price difference with unidirectional DC motors is narrowing.

Therefore, by employing this bidirectional DC motor in a magnetic recording tape running device, the idler and operation switching mechanism can be omitted, and it is believed that the various obstacles and drawbacks mentioned above can be eliminated.

This idea was made based on the above circumstances, and is a simple device that can reliably and quickly perform various operations such as constant speed feeding, fast winding, and stopping of magnetic recording tape even when driven by a bidirectional DC motor. An object of the present invention is to provide a reel shaft mechanism for a magnetic recording tape running device having the following configuration.

An embodiment of this invention will be described below with reference to the drawings.

What is shown in FIG. 1 is a magnetic recording tape running device equipped with a reel shaft mechanism according to an embodiment of this invention, and in the case of this embodiment, the main parts of a tape recorder.

As shown in FIG. 1, the main chassis 10 includes a pair of reel shaft mechanisms 14.16 to which the reel hubs of the tape cassette 12 are mounted, two capstans 18.20, and three capstans 18.20. Book tape cassette position establishment pin 22
, 24, and 26 are prominent.

In addition, as shown in FIG. 1, the chassis 10 has a reel hub attached to a pair of reel shaft mechanisms 14 and 16, and the tape cassette 12 has a reel hub attached thereto. An erroneous erasure prevention switch 30 is provided to prevent erroneous erasure of information already recorded on the stored magnetic recording tape 28.

Further, when the recording button or play button (not shown) is set to the recording mode or the play mode, the electric plunger 31 moves it to the first position where it comes into contact with the magnetic recording tape 28. When the record mode and play mode are canceled,
A pair of magnetic heads 32, 33 and a pair of pinch rollers 34 are moved by an electric plunger 31 to a second position away from the magnetic recording tape 28 as shown in FIG.
, 36 are provided.

The pair of pinch rollers 34, 36 cooperate with the pair of capstans 18, 20 to pinch the magnetic recording tape 28 in the second position.

■The pair of capstans 18 and 20 are as shown in Figure 2.
It is rotatably provided in the chassis 10, and the chassis 1
Below 0, the flywheel that also serves as a pulley 38.4
0 are fixed concentrically.

As shown in FIG. 2, below the chassis 10, there is a bidirectional DC motor 42 which is a rotational force supply means and can rotate in one direction and the other direction with the same characteristics without causing any trouble.
(hereinafter referred to as a DC motor) is provided.

The DC motor 42 rotates at a constant speed in one direction and the other direction when a play button or a recording button (not shown) is set to play mode or recording mode, and a fast forward button (not shown) is set to fast forward mode or rewind mode. When it is rotated, it rotates in one direction and the other direction at a speed faster than the above-mentioned constant speed.

On the output shaft of the DC motor 42, as shown in FIG.
and a second pulley 46 formed concentrically are fixed.

As shown in FIG. 2, a first drive belt 48 is hooked to grooves formed on the outer peripheral surfaces of the first pulley 44 and the pair of flywheels 38, 40 to function as pulleys. ing.

The reel shaft mechanism 14 is connected to the chassis 10 as shown in FIG.
It has a central shaft 50 whose lower end is fixed to.

As shown in FIG. 3, a reel hub engaging member 54 is disposed at the upper end of the central shaft 50, and includes an engaging means 52 that engages a reel hub (not shown) in the circumferential direction of the central shaft 50.

The leave-bub engaging member 54 includes an upper component member 56 whose outer surface is formed into a substantially truncated conical shape to facilitate attachment of a reel hub (not shown).

The upper component member 56 is rotatably provided concentrically around the central axis 50 and is rotatable in the circumferential direction of the central axis 50 with respect to the chassis 10 .

An engaging means 52 is formed on the outer surface of the upper component 56, and in this embodiment, the engaging means 52 is a wing extending in a direction along the center line of the central shaft 50.

As shown in FIG. 3, an annular groove 58 concentric with the central axis 50 is formed in the lower end surface of the upper component 56. As shown in FIG.

The reel hub engaging member 54 also includes a substantially cylindrical lower component member 60 extending downward from the lower end surface of the upper component member 56 along the circumferential surface of the central shaft 50, as shown in FIG.

The lower component member 60 is rotatably provided concentrically around the central axis 50 and is rotatable in the circumferential direction of the central axis 50 with respect to the chassis 10 .

The upper end of the lower component member 60 is coupled to the upper component member 60 by, for example, screwing.
The lower end of the sleeve 62 is located near the upper end surface of a cylindrical sleeve 62 that is rotatably provided concentrically with the central axis 50 below the upper component member 56.

As shown in FIG. 3, the lower end surface of the sleeve 62 is in contact with the upper surface of the chassis 10, and is slidable relative to the upper surface of the chassis 10 in the circumferential direction of the central shaft 50.

A disc-shaped pulley 64 that is disposed concentrically with the central axis 50 is fitted onto the outer peripheral surface of the sleeve 62. This constitutes a second rotating member 66 that rotates.

A groove 67 is formed on the outer peripheral surface of the pulley 64 to function as a pulley, and the groove 67 is connected to the second
It is arranged in the same plane as the pulley 46 of.

As shown in FIG. 3, a first flange 68 extending in the radial direction of the central axis 50 is formed at the lower end of the lower component 60, and the lower surface of the first flange 68 is in contact with this lower surface. It is finished smoothly and abuts against the upper end of the sleeve 62 so that objects in contact with it can slide freely.

An upper end surface of an annular ring 70 arranged concentrically with respect to the central axis 50 is fixed to the lower surface of the first flange 68 .

The lower end of the ring 70 is located near the upper surface of the pulley 64, as shown in FIG.
A flange 72 is formed.

The upper surface of the second flange 72 is finished smoothly so that an object that comes into contact with the upper surface can slide freely.

As shown in FIG. 3, a plurality of wings 74 are formed on the circumferential surface of the lower component member 60, projecting in the radial direction of the central axis 50, and the wings 74 extend along the central axis 50. .

The upper surface of the first flange 68 and the lower end surface of the upper component member 56 are spaced apart in the longitudinal direction of the central axis 50, and one component of the reel hub engaging member 54 is located between the lower end surface and the upper surface. An intermediate component 76 is arranged concentrically with respect to the central axis 50.

The intermediate component 76 has a flange shape projecting in the radial direction of the central shaft 50, and is slidable in the longitudinal direction of the central shaft 50 along the outer peripheral surface of the lower component 60.

Further, the intermediate component 76 engages with the blades 74 in the circumferential direction of the central axis 50, and the blades 74 cause the lower component 60 to engage with the blades 74.
It is adapted to rotate in the circumferential direction as well.

The upper surface of the intermediate component 76 and the groove 58 in the upper component 56
As shown in FIG. 3, a compression coil spring 80 is provided concentrically with respect to the central axis 50.

The upper and lower ends of the compression coil spring 80 are in compressed contact with the bottom surface of the groove 58 and the upper surface of the intermediate component 76, so that the intermediate component 76 is biased by the biasing force of the compression coil spring 80. It is urged to move downward in FIG. 3, that is, in a direction approaching the first flange 68.

The outer peripheral edge of the intermediate component member 76 projects outward from the outer peripheral edge of the first flange 68, and the outer peripheral edge of the intermediate component member 76
6 and the upper surface of the second flange 72 is a substantially disc-shaped first rotating member 81 disposed concentrically with respect to the central axis 50, as shown in FIG. is provided.

At the center of the first rotating member 81 is a circular hole 82 having a radius larger than the radius of the outer circumferential surface of the ring 70 of the lower component member 60 but smaller than the radius of the outer circumferential surface of the second flange 72. is formed.

The circular hole 82 allows the first rotating member 81 to
With respect to the ring 70 of the lower component 60, i.e. the central axis 5
0 and can freely rotate in the circumferential direction with respect to the chassis 10.

The lower surface of the outer peripheral edge of the intermediate component 76 and the first rotating member 8
A variable rotation transmitting means 84 is provided between the upper surface of the rotor 1 and the upper surface of the rotor.

In this embodiment, the variable rotation transmission means 84 is a pressure bonding pad made of felt and having an annular shape.
It is arranged concentrically with respect to the outer periphery and fixed to the lower surface of the outer peripheral edge by well-known means such as adhesive.

Since the intermediate component member 76 is biased downward as shown in FIG. The lower surface of the first rotating member 81 is
It abuts the upper surface of the second flange 72 at a portion near the circular hole 82 .

Therefore, the vicinity portion of the lower surface forms a sliding surface 86 that abuts the reel hub engaging member 54 and the central shaft 50 in the longitudinal direction and slides in the circumferential direction.

As shown in FIG. 3, a protrusion 88 that protrudes downward is formed on the lower surface of the first rotating member 81. As shown in FIG.

The protrusion 88 has an annular shape concentric with the central axis 50 .

A protrusion 90 is formed on the upper surface of the pulley 64 of the second rotation member 66 and protrudes upward from a position radially outward from the outer peripheral surface of the protrusion 88 of the first rotation member 81 .

The protrusion 90 has an annular shape concentric with the central axis 50.

The outer circumferential surface 92 of the protruding portion 88 of the first rotating member 81 and the inner circumferential surface 94 of the protruding portion 90 of the second rotating member 66 are opposed to each other and spaced apart from each other in the radial direction.

Between the outer circumferential surface 92 of the protrusion 88 and the inner circumferential surface 94 of the protrusion 90, as shown in particular detail in FIG. Three shaped rolling members 96 are rotatably arranged at equal intervals in the circumferential direction.

The three rolling members 96 are in contact with the upper surface of the pulley 64 of the second rotating member 66, as shown in FIG. It is designed not to move.

The centers of the three rolling members 96 that are in contact with the upper surface are arranged in the same plane as the sliding contact surface 86 of the first rotating member 81.

The outer circumferential surface 92 of the first rotating member 81 is provided with an inner periphery of the second rotating member 66 that presses three rolling members 96 when the second rotating member 66 rotates in one direction shown by arrow A. The first rotating member 81 is frictionally engaged with the surface 94 to rotate together with the second rotating member 66, and when the second rotating member 66 rotates in the other direction, which is the direction opposite to that indicated by arrow A, 3 A cam member 98 is formed that releases the pressure on each rolling member 96 to release the frictional engagement.

The cam member 98 is made up of three parts corresponding to the three rolling members 96, and each of these three parts has the same shape.

As shown in detail in FIG. 2, each of the above three parts is the shape of a part of a spiral that is assumed to be centered at the center of the central axis 50 and that rotates clockwise from the center and spreads outward. doing.

The dimensions of each of the three portions forming part of the spiral are determined as follows.

As shown in FIG.
When it is most eccentric in the direction directly opposite to the arrow indicating the radius R1, that is, the portion of the inner peripheral surface defining the circular hole 82 of the first rotating member 81 located on the arrow indicating the radius R□ is referred to as the lower part. Even when the structural member 60 is brought into contact with the outer circumferential surface of the ring 70, the distance of the radial gap between the point having the radius R1 and the inner circumferential surface 94 of the second rotating member 66 rolls and the member 9
The dimensions are set to be smaller than the diameter of 6.

Further, the radius R2 of the point closest to the center of the central axis 50 is such that the first rotating member 81 has a radius R2 of the point closest to the center of the central axis 50.
When it is most eccentric in the direction of the arrow indicating , that is, the portion of the inner peripheral surface defining the circular hole 82 of the first rotating member 81 is located on a straight line facing in the direction directly opposite to the arrow indicating radius R2. Even when the member 60 is brought into contact with the outer circumferential surface of the ring 70, the distance of the radial gap between the point having the radius R2 and the inner circumferential surface 94 of the second rotating member 66 rolls and the member 9
The dimensions are set to be larger than the diameter of 6.

Therefore, when the second rotating member 66 is rotated in the direction of arrow A shown in FIG.
The first rotating member 8 is moved in the direction of arrow A while rotating clockwise by slidingly contacting the inner circumferential surface 94 of the first rotating member 8.
1 is most eccentric in the direction opposite to the arrow indicating the radius R1 with respect to the central axis 50, the shape of a part of the spiral of the cam member 9B before reaching the point having the radius R1. The inner circumferential surface 94 is in the same plane as the sliding surface 86 by the
The cam member 9B is held between the inner circumferential surface 94 and a portion shaped like a part of the spiral of the cam member 9B.

Then, the first Rotating member 8
1 is rotated in the direction shown by arrow A together with the second rotating member 66.

Further, when the second rotating member 66 is rotated in the direction opposite to the arrow A shown in FIG. While rotating in the direction, it is moved in the direction opposite to arrow A and the inner peripheral surface 9
The pressure on 4 is released, thus eliminating the frictional engagement,
Even when the first rotating member 81 is most eccentric with respect to the central axis 50 in the direction of the arrow indicating the radius R2, the radius R
2 and the inner circumferential surface 94 of the second rotating member 66 so as to be rotatable.

In this embodiment, the inner circumferential surface 94 of the second rotating member 66 is provided with movement preventing means for preventing the three rolling members 96 from moving upward in FIG. 3 along the center line of the central axis 50. 10
It is also 0.

That is, the inner circumferential surface 94 is an inclined circumferential surface that intersects a straight line B parallel to the center line at an angle α in FIG. 3 with respect to the center line of the central axis 50.

The upper end portion of the inclined peripheral surface is as shown in FIG.
It extends within the locus of movement of the three rolling members 96 in the direction along the center line of the central axis 50 .

In addition, in this embodiment, the outer circumferential surface 92 of the first rotating member 81 forms an angle β smaller than the inclined circumferential surface of the movement prevention means 100, as shown in FIG.
In the figure, it is also a sub-inclined circumferential surface that intersects with straight line B.

As shown in FIG. 2, the reel shaft mechanism 16 includes a cam member 9B.
It has exactly the same structure as the reel shaft mechanism 14, except that the shapes of the three parts forming the reel shaft mechanism 14 are different.

Therefore, regarding the structure of the reel shaft mechanism 16, only the points that are different from the reel shaft mechanism 14 will be explained.

For ease of explanation, the constituent members of the reel shaft mechanism 16 are 100% larger than the corresponding constituent members of the reel shaft mechanism 14.
Further reference numerals will be added, and detailed explanations of the constituent members to which these reference numerals are added will be omitted.

The outer circumferential surface 192 of the first rotating member 181 shown in FIG. Rotating member 1
66 and is frictionally engaged with the inner circumferential surface 194 of the first rotating member 18.
1 together with the second rotating member 166, and when the second rotating member 166 rotates in the other direction opposite to that shown by arrow B), the pressure on the three rolling members 196 is released. A cam member 19B is formed to release the frictional engagement.

The cam member 198 has three cam members corresponding to the three rolling members 196.
It is composed of two parts, and each of these three parts has the same shape.

As shown in detail in FIG. 2, each of the above three parts is the shape of a part of a spiral that is assumed to be centered at the center of the central axis 50 and that rotates counterclockwise from the center and spreads outward. doing.

The dimensions of each of the three parts shaped like a part of a spiral are the same as the radii R1 and R2 in the reel shaft mechanism 14, and corresponding parts with the same radius are given the same reference numerals. A detailed explanation will be omitted.

Therefore, when the second rotating member 166 is rotated in the direction of arrow B shown in FIG. 2, the rolling member 196 rotates clockwise by slidingly contacting the inner peripheral surface 194 of the second rotating member 166. Even when the first rotating member 181 is most eccentric in the direction of the arrow indicating the radius R2 with respect to the central axis 150, the point with the radius R2 and the second It is held rotatably between the inner circumferential surface 194 of the rotating member 166 and the rotating member 166 .

Further, when the second rotating member 166 is rotated in the direction opposite to the arrow B shown in FIG. The first rotating member 181 is rotated in the direction opposite to the arrow B, and the first rotating member 181 has a radius R with respect to the central axis 150.
Even when the cam member 198 is most eccentric in the direction opposite to the arrow indicating 1, the cam member 198
The cam member 19 is pressed against the inner circumferential surface 194 in the same plane as the sliding contact surface 86 by a part shaped like a part of the spiral.
It is held between a part shaped like a part of the spiral No. 8 and an inner circumferential surface 194.

Frictional engagement between the portion shaped like a part of the spiral of the cam member 198 and the rolling member 196 and the rolling member 19
6 and the inner peripheral surface 194 causes the first rotating member 181 to rotate in the direction opposite to the arrow B together with the second rotating member 166.

The groove 67 on the circumferential surface of the pulley 64 of the second rotating member 66 of the reel shaft mechanism 14 configured as described above and the circumferential surface of the pulley 164 of the second rotating member 166 of the reel shaft mechanism 16 configured as described above. Between the groove (not shown) and the second pulley 46 of the DC motor 42, as shown in FIG.
The drive belt 102 is hooked.

Next, the operation of the reel shaft mechanisms 14 and 16 will be explained.

For ease of explanation, it will be assumed that a reel hub (not shown) of tape cassette 12 is engaged with a pair of reel shaft mechanisms 14, 16, as shown by dashed lines in FIG.

A reel hub (not shown) engaged with the reel shaft mechanism 14 has only one end of a magnetic recording tape 28 (not shown) fixed thereto, and a reel hub (not shown) engaged with the reel shaft mechanism 16 has only one end fixed thereto. is magnetic recording tape 2
8 is fixed and a magnetic recording tape 28 is wound thereon.

When the play button (not shown) is set to play mode, ■
A pair of pinch rollers 34, 36 and a pair of magnetic heads 32.
33 is moved upward along the upper surface of the chassis 10 from the first position shown in FIG. 1 by the electric plunger 31 and is placed in a second position (not shown).

In the second position, the pair of pinch rollers 34, 36 cooperate with the pair of capstans 18, 20 to pinch the magnetic recording tape 28, and the pair of magnetic heads 32, 33 grip the magnetic recording tape 28. Pressed.

At the same time, the DC motor 42 rotates in the direction of arrow C at a constant speed.

Then, the pair of capstans 18, 20 are rotated by the first drive belt 4B at the same constant speed in the direction of the arrow.

Furthermore, the second drive belt 102 causes the second rotating member 66 of the reel shaft mechanism 14 to rotate at a constant speed in the direction of arrow A, and the second rotating member 166 of the reel shaft mechanism 16 rotates in the direction of arrow B. The second rotating member 66 of the reel shaft mechanism 16
rotates at the same constant speed.

Therefore, as described above, the first rotating member 81 of the reel shaft mechanism 14 rotates in the direction of arrow A together with the second rotating member 66 by the action of the cam member 98.

At this time, the reel hub engaging member 54
4 is in frictional engagement with the first rotating member 81, thereby rotating together with the first rotating member 81.

Further, the first rotating member 181 of the reel shaft mechanism 16 does not rotate together with the second rotating member 166 due to the action of the cam member 198.

At this time, the magnetic recording tape 28 is connected to the l pair of capstans 18.
20 and a pair of pinch rollers 34 and 36, the magnetic recording tape 28 is sent out at a constant speed from the reel shaft mechanism 16 side to the reel shaft mechanism 14 side by a pair of capstans 18 and 20. be done.

Magnetic recording tape 2 sent out from capstan 18
8 is wound onto a reel hub (not shown) that is engaged with a reel hub engaging member 54 of the reel shaft mechanism 14.

As the diameter of the magnetic recording tape 28 that is being wound up increases, the angular velocity of the reel knob engaging member 54 becomes slower than the angular velocity of the capstan 18, so the torque acting on the reel hub engaging member 54 increases. The variable rotation transmission means 84 reduces the rotation transmission efficiency between the first rotation member 81 and the reel hub engaging member 54 in proportion to the increase in the torque.

Then, the reel hub engaging member 54 connects the variable rotation transmission means 8
The magnetic recording tape 28 is wound up while being rotated in the direction of arrow A at a slower speed than the first rotating member 81 while sliding the magnetic recording tape 4 on the upper surface of the first rotating member 81.

Further, on the reel shaft mechanism 16 side, the magnetic recording tape 28 is pulled out by the capstan 20 from a reel hub (not shown) attached to the reel shaft mechanism 16.

At this time, the first rotating member 181 of the reel shaft mechanism 16
Since the cam member 198 can rotate in the direction of arrow B independently of the rotation of the second rotating member 166, the magnetic recording tape 28 wound around the reel hub (not shown) attached to the reel shaft mechanism 16 The smaller the diameter, the faster the angular velocity can be.

Next, when a fast forward button (not shown) is placed in the rewind mode setting position for causing the magnetic recording tape running device to perform a rewind operation, the DC motor 42 is moved in the direction opposite to the arrow C shown in FIG. rotates at a faster speed than

Then, by the second drive belt 102, the second rotating member 66 of the reel shaft mechanism 14 rotates in the direction opposite to arrow A, and the second rotating member 166 of the reel shaft mechanism 16 rotates in the direction opposite to arrow B. Rotate to .

Further, at this time, the pair of pinch rollers 34 and 36 are not in contact with the pair of capstans 18 and 20, as shown in FIG.
．． 20.

The reel shaft mechanism 14 acts like the reel shaft mechanism 16 during a play operation due to the action of the cam member 98, making it possible to send out the magnetic recording tape 28.

Further, the reel shaft mechanism 16 acts like the reel shaft mechanism 14 during the play operation due to the action of the cam member 198, and winds up the magnetic recording tape 28 from the reel shaft mechanism 14 side.

At this time, even if the diameter of the magnetic recording tape 28 that is being wound around the reel hub (not shown) attached to the reel shaft mechanism 16 increases, the magnetic recording tape 28 is not driven by the capstan 20, so the reel shaft Mechanism 1
The torque acting on the reel hub engaging member 154 of No. 6 does not increase.

Therefore, the variable rotation transmission means (not shown) of the reel shaft mechanism 16 increases the rotation transmission efficiency between the first rotation member 181 of the reel shaft mechanism 16 and the reel hub engaging member 154 to approximately 100%.
Therefore, the reel hub engaging member 154 of the reel shaft mechanism 16 rotates at the same angular velocity as the first rotating member 181 and the second rotating member 166, and winds up the magnetic recording tape 28. go.

Next, it is assumed that the tape recorder 10 is used in a horizontal position from the position shown in FIG. 1, or in an upside down position while remaining horizontal.

At this time, the rolling member 96 of the reel shaft mechanism 16 and the rolling member 196 of the reel shaft mechanism 18 are
3 along the central axis 50 from between the part shaped like a part of the spiral and the inner circumferential surface 94 or 194 of the second rotating member 66 or 166, and The punch tends to fall from between the partially shaped portion and the inner circumferential surface 94 or 194.

However, the above-mentioned dropout is prevented by a movement preventing means 100 constituted by an inclined surface of the reel shaft mechanism 14 and a movement preventing means (not shown) of the reel shaft mechanism 16.

Therefore, the reel shaft mechanisms 14 and 16 can reliably and quickly perform various operations such as constant speed feeding, rapid winding, and stopping of the magnetic recording tape, no matter what posture the magnetic recording tape running device is used in. can.

At the same time, the first rotating member 81 moves upward as shown in FIG. A circular hole 82 is formed with the upper surface inclined relative to the
The inner peripheral surface defining the ring 7 of the reel hub engaging member 54
0 to cause uneven rotation of the reel hub engaging member 54.

However, the upward movement and the inclination of the upper surface of the first rotating member 81 are caused by forming the outer circumferential surface 92 of the first rotating member 81 into the above-mentioned sub-inclined surface, so that the rolling member 96 is This is prevented because it is clamped obliquely upward to the inner circumferential surface 94 of the rotating member 66.

As described in detail above, the reel shaft mechanism of the magnetic recording tape running device is provided concentrically with the central axis provided on the chassis, and extends in the circumferential direction of the reel hub and the central axis. a reel hub engaging member having an engaging means for engaging and rotating in the circumferential direction with respect to the chassis; and a first reel hub engaging member provided on the central axis and rotating in the circumferential direction with respect to the chassis. rotating member and the above reel)
The reel hub engaging member and the first rotating member are provided between the reel hub engaging member and the first rotating member, and the reel hub engaging member and the first rotating member variable rotation transmission means for increasing rotation transmission efficiency between the
A second rotating member is provided on the central axis, has a curved surface facing the curved surface of the first rotating member, and rotates in the circumferential direction with respect to the chassis by the rotational force supplied from the rotational force supply means. a rotating member, provided between the curved surface of the first rotating member and the circumferential surface of the second rotating member so as to be rotatable on its own axis and movable in a direction along the center line of the central axis; A plurality of rolling members, provided on either the circumferential surface of the first rotating member or the circumferential surface of the second rotating member, when the second rotating member rotates in one direction. The plurality of rolling members are pressed and frictionally engaged with the other of the circumferential surface of the first rotating member or the circumferential surface of the second rotating member, thereby moving the first rotating member to the second rotating member. a cam member that rotates together with the second rotating member and releases the pressing force on the plurality of rolling members to eliminate the frictional engagement when the second rotating member rotates in the other direction; An inclined circumferential surface provided on either one of the other circumferential surfaces and extending within the locus of movement of the plurality of rolling members in the direction along the center line and intersecting the center line of the central axis. and a movement preventing means for preventing movement of the plurality of rolling members in the direction along the center line by the inclined surface, so that the rolling member is driven by a bidirectional DC motor. Furthermore, regardless of the position in which the magnetic recording tape is used, various operations such as constant speed feeding, rapid winding, and stopping of the magnetic recording tape can be performed reliably and quickly.

The above-mentioned embodiments are for illustrating this invention, and are not intended to limit this invention in any way, and all modifications and modifications within the technical scope of this invention are also included in this invention. Needless to say.

For example, the variable rotation transmission means 84
A substance that reacts with magnetic lines of force, such as an iron plate, is fixed to the lower surface of the outer peripheral edge of the intermediate component 76 of No. 4, and this iron plate is attracted by the magnetic force of an electromagnet installed on the upper surface of the first rotating member 81. good.

Furthermore, the number of rolling members 96 and 196 is not limited to three, but may be two, four, or five or more.

Further, the rolling member 96 is not limited to a spherical shape,
It may be cylindrical or cylindrical.

Further, the outer circumferential surface 92 of the first rotating member 81 does not have to be a sub-inclined circumferential surface, and may be a circular outer circumferential surface concentric with the center line of the central axis 50 as shown in FIG. good.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the chassis of the main part of a magnetic recording tape running device equipped with a reel shaft mechanism according to an embodiment of the invention, and FIG. 2 is a cross-sectional view taken along line n-■ in FIG. FIG. 3 is a longitudinal sectional view of the reel shaft mechanism, and FIG. 4 is a partial view of a modification of this invention. FIG. 10... Chassis, 14, 16... Reel shaft mechanism, 42... Bidirectional DC motor, 5
0... Central axis, 52... Engagement means, 5
4... Reel hub engaging member, 66...
Second rotating member, 81...First rotating member, 8
4... Variable rotation transmission means, 92... Outer circumferential surface, 94... Inner circumferential surface, 96... Rolling member, 98...・Cam member, 100...
Movement prevention means.

Claims (2)

[Scope of utility model registration request] (1) In a reel shaft mechanism of a magnetic recording tape running device that rotates by being driven by a rotational force supply means provided on a chassis equipped with a reel hub on which a magnetic recording tape is wound, a central shaft provided on the chassis. and; a reel hub engaging member that is provided concentrically with the central axis and has an engaging means that engages the reel hub in the circumferential direction of the central axis, and that rotates in the circumferential direction with respect to the chassis; a first rotating member provided on the central axis and rotating in the circumferential direction with respect to the chassis; provided between the reel hub engaging member and the first rotating member, the reel hub engaging member is provided between the reel hub engaging member and the first rotating member; variable rotation transmission means that increases the rotation transmission efficiency between the reel hub engaging member and the first rotating member in substantially inverse proportion to the strength of the torque acting on the member; a second rotating member having a circumferential surface facing the circumferential surface of the first rotating member and rotating in the circumferential direction relative to the chassis by a rotational force supplied from the rotational force supplying means; A plurality of rolling members are provided between the circumferential surface of the rotating member and the circumferential surface of the second rotating member so as to be freely rotatable and movable in a direction along the center line of the central axis. and; provided on either the circumferential surface of the first rotating member or the curved surface of the second rotating member, and the plurality of rolling members when the second rotating member rotates in one direction. is pressed and frictionally engages with either the surface of the first rotating member or the surface of the second rotating member to rotate the first rotating member together with the second rotating member. a cam member that releases the pressing force on the plurality of rolling members to eliminate the frictional engagement when the rotating member 2 rotates in the other direction; the other of the cam member or the peripheral surface; an inclined surface provided on either one of the plurality of rolling members and extending within the locus of movement of the plurality of rolling members in a direction along the centerline and intersecting the centerline of the central axis; A reel shaft mechanism for a magnetic recording tape running device, comprising: movement preventing means for preventing movement of each rolling member in a direction along the center line. (2) Either the cam member or the other of the circumferential surface has a secondary inclined surface that intersects the center line at a smaller intersecting angle than the inclined circumferential surface and contacts the plurality of rolling members. A reel shaft mechanism for a magnetic recording tape running device according to claim 1, characterized in that the reel shaft mechanism is provided in a magnetic recording tape traveling device.