JP2000173132A - Capstan break device of magnetic recording and reproducing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the braking power applied to a capstan motor in order to suppress a rocking back phenomenon at the time of intermittent frame feed reproduction of a VTR. SOLUTION: A brake lever 13 for applying the braking power to the capstan motor 56 is so constituted as to be changeable in the braking power. The braking power to the capstan motor 56 is changed in a forward direction intermittent frame feed reproduction mode and a backward direction intermittent frame feed reproduction mode by driving the lever 13 by a means for switching the driving of mechanism members in correspondence to the operation mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan brake device for a tape running drive of a magnetic recording / reproducing apparatus, and more particularly to a capstan brake useful for intermittent reproduction of a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art A recorded magnetic tape cassette is loaded into a magnetic recording / reproducing apparatus (hereinafter, referred to as a VTR), and the magnetic tape is arranged in a predetermined tape traveling mechanism to reproduce (play) and rewind (review). ), Fast forward playback (queue), fast forward, rewind, slow playback, still playback,
A tape traveling drive mechanism is provided which drives and controls the traveling direction and speed of the magnetic tape in accordance with various operation modes of the VTR such as double-speed reproduction, forward intermittent frame advance reproduction or reverse intermittent frame advance reproduction.

A driving mechanism of the magnetic tape will be described with reference to FIGS. 4 and 5. FIG. 4 is a perspective view of a magnetic tape drive mechanism arranged on the front surface of the chassis, and FIG. 5 is a perspective view of a magnetic tape drive mechanism arranged on the rear surface of the chassis.

[0004] An electric motor 42 is arranged on the side surface of a chassis 41 of the VTR, and a worm gear 43 is attached and fixed to a rotating shaft of the electric motor 42. The rotation of the electric motor 42 includes a worm gear 43, a first gear 44 including a large-diameter gear 44a and a small-diameter gear 44b,
A second gear 45 composed of a gear 45a on the circumference and a bevel gear (not shown) 45b formed in a planar shape;
The gear is transmitted to a rack 49 formed at one end of a slider 48 via a third gear 46 composed of a 6a and a small diameter gear 46b and a cam gear 47 composed of a large diameter gear 47a and a small diameter gear 47b. It slides along the guide groove 50 in the AB direction shown by the arrow in the figure. The chassis 41
On the front surface, reel stands 51a and 51b on which reels of a tape cassette (not shown) are mounted, and a pair of tape pull-out poles 53 for pulling out a magnetic tape from the tape cassette and winding it around a cylinder 52 having a built-in rotary head,
54, guide grooves 55a and 55b for slidingly guiding the tape pull-out poles 53 and 54, and a capstan motor 5
6a and a pinch roller 57 are arranged. The tape pull-out poles 53 and 54 include tape guide poles 53a and 54a and inclined posts 53b and 54b, and tape guide poles 53a and 54a and inclined posts 53.
b, 54b, which are attached to and fixed to each other.
3, 54, and by a drive mechanism described later,
It is slid along the guide grooves 55a and 55b and wound around the cylinder 52. A magnetic tape is also stretched between the capstan 56a and the pinch roller 57. During driving of the magnetic tape, the pinch roller 57 is slid by a driving mechanism (not shown) to move the magnetic tape to the capstan 56a. The magnetic tape is run by the rotation of the capstan motor 56 in close contact. The rotation of the capstan motor 56 is transmitted by a belt 59 stretched between a belt wheel 56b and a reel driving belt wheel 58 disposed on the back side of the chassis 41. The reel drive belt wheel 58 is provided with a oscillating drive gear 58a coaxially. Oscillating gears 58b and 58c constituting an oscillating mechanism are meshed with the oscillating gear 58a.
The gears 8b and 58c mesh with the gear 51a 'of the supply reel 51a or the gear 51b' of the take-up reel 51b in accordance with the rotation direction of the drive belt gear 58, and transmit the rotation of the capstan motor 56.

A rack 60 is formed on the other side of the slider 48 on the rear surface of the chassis 41, and a large-diameter gear 61a of a loading gear 61 meshes with the rack 60.
The loading gear 61 is a small-diameter gear 6 fixed coaxially.
1b. A pair of left and right small gears 62a, 62b mesh with a small diameter gear 61b of the loading gear 61. One ends of fixed pieces 63a, 63b are fixed to the shafts of the small gears 62a, 62b.
The other end of 63b is rotatably attached to one end of rocking pieces 64a, 64b. The tape pull-out poles 53 and 54 are implanted at the other ends of the rocking pieces 64a and 64b. A cam portion 6 is provided at the side end of the slider 48.
5 are formed, and the cam portion 65 is formed by stepped portions 65a and 65b having different widths in two stages. One end of a substantially U-shaped brake lever 66 whose center portion is rotatably fixed on a fixed shaft is in sliding contact with the cam portion 65, and the other end of the brake lever 66 is A brake pad 66a for rotatingly rotating the rotor of the capstan motor 56 is adhered.
One end of a spring 66b for attaching the brake pad 66a to the rotor of the capstan motor 56 at all times is attached to the other end of the spring 66b.
The other end of 6b is fixed to the chassis 41.

That is, one end of the brake lever 66 is rotated by the stepped portions 65a, 65b of the cam portion 65 against the elastic force of the spring 66b by the sliding of the slider 48, and the brake pad 66a is moved. The rotor of the capstan motor 56 is brought into frictional contact with the rotor to provide braking.

The slider 48 has a first guide groove 67 and a second guide groove 68 formed therein.
The guide groove 67 is a guide groove for a pinch roller lever (not shown) for slidingly moving the pinch roller 57, and the second guide groove 68 is for driving the reel stand brake (not shown). This is a guide groove for the lever to be used. Although not shown, the second gear 45
Also operates to drive a cassette transport mechanism for driving a cassette base on which a tape cassette is mounted between a tape cassette mounting / dismounting position and a reel base provided on the chassis 31.

In the magnetic tape driving mechanism having such a configuration, the second gear 45 is rotated by the rotation of the electric motor 42 to move the tape cassette to the reel table 51a.
The magnetic tape is loaded between the capstan 56a and the pinch roller, and the slider 48 is further slid to wind the magnetic tape around the cylinder 52 by the tape pull-out poles 53 and 54.

In this state, for example, when a reproduction mode is set by an operation mode setting of a VTR (not shown), the electric motor 42 rotates, and the slider 48 is moved in the direction of arrow A to a position corresponding to the reproduction mode. Slide up to. As a result, the pinch roller 57 is driven by the first groove 67, and pinches the magnetic tape with the capstan 56a.

When the capstan motor 56 rotates, the magnetic tape is fed from the supply reel of the cassette, and is taken up by the take-up reel of the cassette through the tape draw-out pole 53, the cylinder 52, the tape draw-out pole 54, and the capstan 56. In this way, according to the operation mode, the magnetic tape is caused to run in the forward or reverse direction at a predetermined speed at the time of performing recording or reproduction, or at a higher or lower speed.

In the VTR, in addition to the operation mode for continuously running the magnetic tape as described above, there is an intermittent frame feed reproduction operation mode for intermittently running the magnetic tape. In this intermittent operation mode, the capstan motor 56 is operated in order. The video signal recorded on the magnetic tape is stopped by repeating the operation of instantly rotating the magnetic tape in the direction or the reverse direction and then stopping, sending the magnetic tape in the forward or reverse direction for one frame, for example, and then stopping for a predetermined time. Play as a frame-by-frame video of the image.

In the reel drive system shown in FIG. 5, when intermittent frame feed reproduction is performed, the capstan motor 56 repeatedly rotates and stops.
b and the belt 5 stretched over the reel drive belt wheel 58
9 is larger than the tension on the supply side (the side toward the reel drive belt wheel 58) on the winding side (the side toward the belt wheel 56b).
At the moment when the motor 6 stops, a rotational force is applied to the belt wheel 56b in a direction to eliminate the difference in the tension of the belt 59, and a so-called swingback phenomenon occurs in which the capstan motor 56 rotates in a direction opposite to the rotation before the stop. . At this time, since the reel drive belt wheel 58 also slightly rotates under the influence of the swing back phenomenon, the magnetic tape moves at that moment, the tracking of the magnetic head reproducing the video signal is disturbed, and the reproduced screen shakes. Occurs.

In order to suppress the occurrence of such a swing-back phenomenon, a proposal has been made to apply a brake to the capstan motor. That is, the capstan motor is braked constantly to prevent the capstan motor from rotating in the reverse direction during intermittent feeding. Conventionally, the braking force of this brake has been set to a constant value regardless of the rotation direction of the capstan motor. Due to the difference in the running path of the magnetic tape, the rotational torque of the capstan motor is different from the case where the magnetic tape is rotated in the reverse direction compared to the case where the magnetic tape is rotated in the same forward direction as during normal recording and reproduction. Is generally set to be larger, and the braking force for swing-back suppression is also set to a larger value in accordance with the reverse rotation.

On the other hand, from the viewpoint of operation mode setting,
Also in the forward / reverse intermittent feed reproduction mode, the mode is set by driving the slider 48 in FIG. 5, but it is often physically difficult to provide a dedicated position, and it is common to share the position with other positions. In general, it is constituted.
That is, for example, in the forward intermittent playback, the same position as in the normal playback mode is used, and in the reverse intermittent playback, the position in the reverse playback mode is used.

Accordingly, a braking force which is originally not necessary is always applied to the capstan motor at the time of normal reproduction and reverse reproduction, so that the load of the capstan motor 56 is increased.

[0016]

As described above, in the conventional VTR, in order to suppress the swing-back phenomenon at the time of the intermittent feed reproduction, the capstan motor needs to have the necessary control during the reverse rotation where the rotation torque is large. Since the power brake was applied, there was a problem that the load on the capstan motor increased.

According to the present invention, there is provided a magnetic recording / reproducing apparatus which does not increase the load on the cabstan motor more than necessary by arranging the brakes with different braking forces in accordance with the rotation direction of the capstan motor. An object is to provide a capstan brake device.

[0018]

According to the present invention, there is provided means for intermittently driving a magnetic tape in forward and reverse directions by a capstan motor, and applying a braking force to the capstan motor during the intermittent drive of the magnetic tape. A capstan brake device for a magnetic recording / reproducing apparatus provided with a brake means for applying the magnetic tape, wherein the brake means controls the capstan motor differently depending on whether the magnetic tape is intermittently driven in the forward direction or in the reverse direction. Is provided.

Further, the brake means is configured such that the braking force during the intermittent driving in the reverse direction is greater than the braking force during the intermittent driving in the forward direction.

The brake means includes a brake lever, a brake piece displaceably connected via an elastic body having a biasing force in a direction away from the brake lever, and a brake piece provided on the brake piece. A brake pad that is in contact with the rotor of the capstan motor; and a drive unit that drives the brake lever. The drive unit applies a first elastic force to the elastic body by the drive unit according to the direction of the intermittent drive. And a second position for applying a second braking force based on a second elastic force greater than the first elastic force.

Further, the first braking force is the braking force during the intermittent driving in the forward direction, and the second braking force is the braking force during the intermittent driving in the reverse direction.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view showing one embodiment of a capstan motor brake in an intermittent feed mode of a magnetic recording / reproducing apparatus according to the present invention. FIG. 1 shows only the capstan motor brake part in the intermittent feed mode in the magnetic tape drive mechanism of the magnetic recording / reproducing apparatus, and the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals.

The rotation of the electric motor 42 is controlled by the worm gear 4
3 to first to third gears 44 to 46 and cam gear 47
Is transmitted through the speed reducer to slide the slider 48.

The cam gear 47 is provided with the intermittent brake cam 11 fixed coaxially. On the surface of the intermittent brake cam 11, an intermittent brake cam groove 12 having a cam surface having a different radius in the rotation direction is formed. The intermittent brake cam groove 12 has three types of radii r1 and r2.
This radius sets the swing distance of the intermittent brake lever 13 described later, and each radius has a relationship of r1 <r2 <r3. The intermittent brake lever 13 has a substantially U-shaped shape, and one end of the guide post 1 fitted in the intermittent brake cam groove 12.
3a, the intermediate portion is rotatably attached to the fixed shaft 13b planted from the chassis 41, and the other end is the elastic member 1
4 is attached and fixed. A fixed shaft 13b rotatably attached to an intermediate portion of the intermittent brake lever 13
Is provided with a brake piece 15 having one end rotatably attached thereto, and a brake pad 15a that contacts the capstan motor 51 at the other end of the brake piece 15. The brake pad 15 of this brake piece 15
a at the end provided with the intermittent brake lever 13
The other end of the elastic body 14 provided at the other end is fixedly mounted. The elastic member 14 applies an elastic force in a direction in which the intermittent brake lever 13 and the brake piece 15 repel each other around the fixed shaft 13.

In the VTR having the capstan motor brake device configured as described above, the tape cassette is conveyed onto a reel table, and the magnetic tape is arranged so as to be driven by a tape driving mechanism. The intermittent brake lever 13 is driven in accordance with the operation mode set by the no VTR operation mode setting means. The operation will be described with reference to FIG.

Now, assuming that the reproduction mode is set, the electric motor 42 performs a predetermined rotation, whereby the slider 48 slides to a position corresponding to the reproduction mode. Thereby, the pinch roller is pressed against the capstan, and the magnetic tape is driven at a constant speed. The cam gear 47 also rotates at the same time, so that the guide post 13a of the intermittent brake lever 13 is positioned at the radius r2 of the intermittent brake cam groove 12, as shown in FIG. In this state, the brake pad 15a is pressed against the rotor of the capstan motor 56 solely by a pressing force based on the elastic force of the elastic body 14, and a small value of braking force is applied to the capstan motor.

Next, when the forward intermittent reproduction mode is set, the electric motor 42 does not rotate, and each mechanism member maintains the same state as in the reproduction mode. That is, the intermittent brake lever 13 applies the same small braking force to the rotor of the capstan motor 56 as during normal reproduction. The operation state of each mechanism member is the same as that in the reproduction mode, in addition to the forward intermittent reproduction mode, there is a forward high-speed low-speed reproduction mode, and the position of the slider 48 and the rotation position of the cam gear 47 are the same.
As shown in FIG. As a result, it is possible to suppress the occurrence of the swing back phenomenon in the forward intermittent reproduction mode.

Next, when the reverse intermittent reproduction mode is set, the electric motor 42 rotates, the slider 48 moves to the position in the reverse relation reproduction mode, and the cam gear 47 rotates accordingly. Thereby, the intermittent brake lever 13
Means that the guide post 13a is
From the position of the radius r2 to the position of the radius r1. As a result, the intermittent brake lever 13 is
1, the elastic body 14 contracts, and the brake pad 15 a is pressed against the capstan motor 56 with a larger force. That is, a large braking force is applied to the capstan motor 56. As a result, it is possible to suppress the occurrence of the swing back phenomenon in the reverse intermittent reproduction mode.

In the reverse intermittent reproduction mode, the operating states of the mechanism members are the same as the reverse reproduction mode and the reverse high-speed low-speed reproduction mode.
7, the same braking position is applied, and as shown in FIG.

When the fast forward rewind mode is set, the electric motor 42 rotates correspondingly, the slider 48 moves, the cam gear 47 rotates, and the guide post 13a of the intermittent brake lever 13 It is located at the radius r3 of the intermittent brake cam groove 12. In this state, the intermittent brake lever 13 rotates counterclockwise in FIG. 1 around the shaft 13b, the pressure contact of the brake pad 15a with the rotor of the capstan motor 56 is released, and the braking force is released.

As described above, the intermittent brake lever 13 is driven by the intermittent brake cam groove 12 provided on the cam gear 47 according to the operation mode, so that the optimal intermittent reproduction in the forward direction and the intermittent reproduction in the reverse direction are respectively performed. The braking force can be applied to the capstan motor, and the swing-back phenomenon is effectively eliminated.

Next, a modification of the present invention will be described with reference to FIG.

FIG. 3A shows a modified example of the intermittent brake cam 11 which is coaxially fixed to the cam gear 47. The outer periphery of the intermittent brake cam 31 has r1 to r3 having different radii in the rotation direction. An arcuate cam surface is formed. An urging spring 32 that applies an urging force to the intermittent brake lever 13 is attached to the cam surface of the intermittent brake cam 31 so that the guide post 13a of the intermittent brake lever 13 slides in contact.

The state in which the guide post 13a is positioned at the radius r1 of the intermittent brake cam 31 due to the rotation of the intermittent brake cam 31 is the position of the reverse traveling system including the reverse intermittent regeneration mode, and the capstan motor. Large braking force.

The guide post 13a is an intermittent brake cam 3.
The state located at the radius r2 of 1 is the position of the forward running system including the forward intermittent playback mode, and a small braking force is applied to the capstan motor.

The guide post 13a is an intermittent brake cam 3.
The state located at the radius r3 of 1 is the position of the fast-forward rewind mode, and no small braking force is applied to the capstan motor.

FIG. 3B shows a modification in which the cam portion 33 for driving the intermittent brake lever 13 is provided on the slider 48. If there is no risk that the driving operation of each mechanism member, which is the original function of the slider 48, is hindered, the cam portion 33 can be formed on the slider 48 to drive the intermittent brake lever 13. The intermittent braking cam portion 33 includes a plane t1 with which the guide post 13a of the intermittent brake lever 13 abuts in the reverse traveling system mode including the reverse intermittent feeding regeneration mode, and a forward traveling including the forward intermittent feeding regeneration mode. A plane t2 with which the guide post 13a of the intermittent brake lever 13 abuts in the system mode and a plane t3 with which the guide post 13a of the intermittent brake lever 13 abuts in the fast forward rewind mode. The dimensional difference in the width direction of each of the planes t1 to t3 corresponds to the dimensional difference between the radiuses r1 to r3 of the cam surfaces of the intermittent brake cam groove 12 in FIG. 1 and the intermittent brake cam 31 in FIG.

When the slider 48 slides in accordance with the setting of the operation mode, the contact position of the guide post 13a changes, and when the slider 48 comes into contact with the plane t1, the intermittent brake lever 13 rotates around the shaft 13a as shown in FIG. , And a large braking force is applied to the capstan motor 56.

When the guide post 13a comes into contact with the plane t2, the intermittent brake lever 13 rotates counterclockwise about the shaft 13a in the figure, so that the pressure contact force of the intermittent brake piece 15 is weakened and the cabstan motor 56 has a small force. Braking force is applied.

When the guide post 13a comes into contact with the plane t3, the intermittent brake lever 13 further rotates counterclockwise about the shaft 13a in the drawing, and the brake pad 15a of the intermittent brake piece 15 rotates the rotor of the capstan motor 56. , And no braking force is applied.

In the above description, the operating position of the mechanism member driven by the slider is common to the forward running system and the reverse running system, and the operating mode position of the cam gear is also set commonly. But originally,
The purpose of applying the brake to the capstan motor is to suppress the swing back during intermittent frame-feed playback.In the mode in which the magnetic tape is played while running continuously at the same speed, the capstan motor brake is unnecessary. is there.
Therefore, it is needless to say that the capstan motor can be braked only in the normal / reverse intermittent frame feed reproduction mode if a position where the cam gear can set the normal / reverse intermittent frame feed reproduction mode can be secured.

As described above, according to the present invention, the braking force applied to the capstan motor in order to suppress the swing-back phenomenon during the intermittent frame feed reproduction is switched between the forward intermittent frame feed mode and the reverse intermittent frame feed mode. Since the capstan motor can be set individually, it is possible to apply the optimal braking force to the capstan motor in each intermittent frame feed mode. It is possible to solve the problem of increasing the load on the device.

[0043]

According to the present invention, it is possible to apply different braking forces to the capstan motor during forward intermittent frame forward reproduction and reverse intermittent frame forward reproduction, thereby increasing the load on the capstan motor. Instead, it is possible to suppress the swing back phenomenon with the minimum necessary braking force.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a capstan motor brake device for a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a plan view for explaining the operation of the capstan motor brake device of FIG. 1;

FIG. 3 is a plan view showing a modification of the embodiment of the present invention.

FIG. 4 is a perspective view showing a surface of a magnetic tape drive mechanism of a conventional VTR.

FIG. 5 is a perspective view showing the back surface of a magnetic tape drive mechanism of a conventional VTR.

[Explanation of symbols]

11: intermittent brake cam, 12: intermittent brake guide groove,
13 intermittent brake lever, 14 elastic piece, 15 intermittent brake piece, 42 electric motor, 44 first gear, 4
5 second gear, 46 third gear, 47 cam gear,
48: slider, 49: linear gear, 56: capstan motor, 58: reel drive belt wheel, 59: belt.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] December 21, 1998 (1998.12.
21)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

[Correction method] Change

[Correction contents]

FIG. 4

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

Claims (4)

[Claims] 1. A magnetic recording system comprising: means for intermittently driving a magnetic tape in a forward direction and a reverse direction by a capstan motor; and brake means for applying a braking force to the capstan motor when the magnetic tape is intermittently driven. In the capstan brake device for a playback device, the brake means is configured to apply different values of control force to the capstan motor when the magnetic tape is intermittently driven in the forward direction and when the magnetic tape is intermittently driven in the reverse direction. A capstan motor brake device for a magnetic recording / reproducing device, comprising: 2. The brake device according to claim 1, wherein the braking means is configured such that a braking force during the intermittent driving in the reverse direction is greater than a braking force during the intermittent driving in the forward direction. Capstan motor brake device for magnetic recording / reproducing equipment. 3. The brake means is provided with a brake lever, a brake piece displaceably connected via an elastic body having a biasing force in a direction away from the brake lever, and provided on the brake piece. A brake pad that is in contact with the rotor of the capstan motor; and a drive unit that drives the brake lever. The drive unit applies a first elastic force to the elastic body by the drive unit according to the direction of the intermittent drive. A first position for providing a first braking force based on the first elastic force, and a second position for providing a second braking force based on a second elastic force larger than the first elastic force. The capstan motor brake device for a magnetic recording / reproducing apparatus according to claim 3, wherein 4. The method according to claim 3, wherein the first braking force is a braking force during the forward intermittent driving, and the second braking force is a braking force during the reverse intermittent driving. A capstan motor brake device for a magnetic recording / reproducing apparatus as described in the above.