JPS5979457A - Tape driving system - Google Patents

Abstract

PURPOSE:To ensure an effective use of space and at the same time to miniaturize a VTR by setting a pair of loading posts asymmetrically to an axis Y and having an asynmmetrical form of a tape traveling route between the inlet and outlet sides of a rotary drum. CONSTITUTION:A cassette 26 is loaded on a reel drive disks 27 and 28 so that a loading post 20 of the inlet side consisting of a pair of slant posts 21 and a vertical post 22 set outside the posts 21 and a loading post 23 of the output side consisting of a slant post 24 and a vertical post set outside the poste 24 are put into a space part 260 formed at the end part of the cassette 26. When the loading is through with the cassette 26, the posts 20 and 23 move along grooves 29 and 29 provided to a base board 30. A magnetic tape 31 is wound in an M- shape round the circumference surface of a rotary drum 32. In such a way, the tape 31 is loaded along a prescribed tape traveling route.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a tape running system of a video tape recorder (hereinafter referred to as VTR), and particularly to a VTR in which a magnetic tape is wound around a rotating drum using an M loading method. This relates to the tape running system.

BACKGROUND OF THE INVENTION In general, most cassette-type VTR heads use a helical scan method. In the tape running system of a VTR that uses this helical scan method, in order to run the tape smoothly and stably,
■The running posture of the tape at the outlet of the supply reel and the inlet of the take-up reel is that the height is equal and the running direction is parallel to the reference plane (substrate) parallel to the plane formed by the bottom of the cassette. The width direction of the tape must be perpendicular to the reference plane,
and ■ The tape should be wound diagonally along a lead provided diagonally on the circumferential surface of the rotating drum, and further, ■ The tape should not be twisted between the guide bodies.
Vermilion items such as these are required.

Stable running of the tape means that the magnetic tape runs without uneven tension distribution, that is, when the magnetic tape is cut in its width direction, the tension distribution at each point on the cut surface is uniform and uniform. refers to a state where

Incidentally, in order to achieve this stable running, VTRs in which a magnetic tape is wound around a rotating drum using the M loading method have recently been widely used. this is,
The basic tape running system consists of a rotating drum tilted in a predetermined direction at a predetermined angle, a pair of inclined posts on the input side and output side, and a pair of inclined posts arranged on the outside of each of these inclined posts. It consists of a pair of vertical posts around which the tape is wrapped at a predetermined angle, and the shape, dimensions, inclination angle, etc. of each part are set to satisfy the above-mentioned stable tape running conditions. In a tape running system employing this M loading method, the tape is wound around a rotating drum according to the following procedure and runs along the slope of its circumferential surface.

First, a cassette containing a tape is loaded into the supply and take-up reel table of the VTR, and then the inlet side and outlet 11jll of a rotating drum consisting of the inclined post 1, the vertical post 2, the inclined post 3, and the vertical post 4 are loaded. A pair of loading posts 5.6 provided on the base move along guide grooves (not shown) provided on the base, and the tape 9 is wound around the rotating drum 10 in an M-shape as shown in FIG. ,
The tape is loaded along a 9F fixed tape running path. Next, when the tape 9 is run, as shown in FIG. It runs parallel to a reference plane A that is parallel to the cassette, and its width direction is perpendicular to the reference plane A. Then, the tape 9 is sent out from the vertical post 2 on the entrance side to the inclined post 1 on the entrance side in one predetermined corner. Next, at this inclined post 1, the tape 9 is held at a predetermined angle α with respect to the reference plane A.
It is bent downward at a distance t1 from the inclined post 1 and is wound around the rotary drum 10 at an angle β shown in FIG. 1 from a position a height hl lower than the reference plane A. The tape 9 is wound around the drum 10 at an angle of β/2 at a point P where the center axis Z-Z of the drum intersects with the lead 13° (this point P is located on the Y axis, which will be described later), and the lead 13 The tape winding is made to coincide equally with the height of the reference plane A, that is, the height of the entrance and exit of the supply reel and the take-up reel at a position (located exactly at the midpoint of the angular range β). That is, the angle IWθ of the leads 1 and 3, the oblique angle γ of the rotating drum 10 in the X-axis direction with respect to the Y-axis, and its height are set so that the point P coincides with the base plane A at the same height. Ru. Thereafter, the tape 9 is applied in exactly the same manner as described above, but in reverse, symmetrical about the Y axis, along the lead 13 to the inclined post 3 on the exit side, which is a distance t2 from a position that is a height h2 higher than the reference plane A%. It is fed out with the neck left at an angle α downward. The tape 9 is bent at a predetermined angle by the inclined post 3, returned to a height and running attitude equal to the height and attitude at the vertical post 2 on the entrance side, and then sent to the vertical post 4 on the exit side.

In this way, the tape can be run smoothly and stably without creating any gaps between the tape and the circumferential surface of the rotating drum, or without twisting or slipping during the run.

However, in the conventional tape running system, the distance t1 from the artificial side inclined post 1 to the tape inlet of the rotating drum 10 is equal to the distance 1'1l from the tape outlet to the outlet side inclined post 3.
lt2 and lead 1 at the tape entrance
30, the height hl from the reference plane A is equal to the height h2 of the lead 13 on the exit side. In other words, the heights of the leads at the tape inlet and outlet are vertically symmetrically set to the same height across the reference plane A.

That is, 'l = t2 + hl = h2.

Therefore, as shown in Figure 1, the center line is
The center line passing through the center of the 9-axis rotating drum and perpendicular to the X axis is Y.
When tape loading is completed, the arrangement relationship must be set so that the loading posts 5 and 6 are positioned symmetrically on the inlet and outlet sides of the rotating drum 10 with the Y-axis in between. Must be. In other words, the tape running path must be shaped symmetrically across the rotating drum. This results in a fixed condition that the loading posts must be symmetrical regardless of the configuration of the VTR. Therefore, the role conditions of VTR design are extremely limited. For example, depending on the configuration of the VTR, the tape path may have an asymmetrical shape on the inlet and outlet sides of the rotating drum, and This is difficult to apply in cases where it is desired to set the left and right loading posts at asymmetric positions at the tape loading position, and the flexibility of the VTR's crotch movement is significantly impaired. Also,
Due to such restrictions on design conditions, the tape path around the drum is also fixed, which creates space constraints and makes it difficult to utilize the space effectively.

DISCLOSURE OF THE INVENTION The present invention was made to solve the above-mentioned problems in the tape running system of a conventional VTR. By arranging the tape at an asymmetric position with respect to the axis and making the tape running path formed by the rope/first ring boss asymmetric at the entrance and exit sides of the rotating drum, it is possible to select and set the tape path around the rotating drum. This eliminates constraints on VTR design, increases the degree of freedom in design, increases the degree of freedom in selecting the tape path around the drum, and improves the effective use of space by at least the amount of space shortened by the asymmetrical shape. V that can be made smaller
The purpose is to provide a tape running system in TR.

In order to achieve this object, the present invention provides D'
A VTR is equipped with a rotating drum that is tilted at a fixed angle, a tilted post and a vertical post placed on the outside thereof, and a pair of loading posts that pull out a magnetic tape from a tape cassette and wrap it around the rotating drum. The tape path provided on the circumferential surface of the rotating drum is routed from the inlet-side inclined post to the inlet of the rotary drum, which is formed by a middle wing post located at the midpoint of the tape winding angle range from the tape inlet to the outlet. The present invention is characterized in that one of the distance from the rotary drum outlet to the outlet-side inclined post is longer and the other is shorter.

According to this invention, it is possible to arrange the left and right loading posts at asymmetrical positions on the population side and the outlet side of the rotating drum. Therefore, the tape running path formed by the loading bow and stop can be made into an arbitrary and desired asymmetrical shape between the inlet and outlet sides of the rotating drum, reducing the second constraint on conventional VTR design. Yes, VTR
The degree of freedom in design is greatly improved, such as by selecting and setting the tape path according to the situation. However, this also increases the degree of freedom in selecting the tape route around the citram, and for example, it becomes possible to provide a space approximately equivalent to the shortened space on the short end of the tape route or on the exit side. This allows for effective use of space, such as allowing other mechanical parts to be placed.

Deer also try to save space by making effective use of space.
VTl can be made more compact.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to FIG. 3 and subsequent drawings.

FIG. 3 schematically shows a tape running system according to the present invention. In this tape running system, the tape is wound around a rotating drum using the M loading method in the following procedure.

First, there is a loading post 20 on the entrance side, which is made up of a pair of inclined posts 21 and a vertical post 22 arranged on the outside thereof, and a loading post 23 on the exit side, which is made up of a pair of inclined posts 24 and a vertical post 25 arranged on the outside thereof.
The cassette 26 is loaded onto the reel stand 27, 28 so that the cassette 26 and the cassette 26 enter the space 260 formed at the end of the cassette 26.

Next, when loading of the cassette 26 is completed, the loading post 20.23 is inserted into the groove 29.23 provided in the base 30.
The magnetic tape 31 is wound around the circumferential surface of the rotating drum 32 in an M-shape. In this way, the magnetic tape 31 is loaded along a predetermined tape running path. In the figure, 33 is a pack tension post for applying bank tension to the tape, 34 is a full-width erasing head, 35 is an impedance roller on the entrance side, and 36 is an impedance roller on the exit side. Further, 37 is a four-tone erasing head, 38 is an audio and control head arranged in parallel with the audio erasing head, 39 is a capstan, and 40 is a tape 31 between the capstan 39 and a predetermined position. This is a 7th inch pinch roller that runs in the direction.

Next, FIG. 4 shows the basic configuration of the present invention, in which the tape 31 is pulled out from the cassette 26 by the tape running system as described above, wound around the circumferential surface of the rotating drum 32, and loaded onto a predetermined tape path. It shows the state that has been applied.

In this tape running system, when the tape 31 is run as shown by the arrow 100, the tape 31 is transferred to the supply reel 261.
from the cassette outlet 5o to the vertical post 22 on the inlet side.
This vertical post 21 wraps around the inlet side inclined post 22 at a predetermined angle. The tape 31 between the outlet 5o and the inclined post 22 on the inlet side of the cassette is
Parallel to the reference plane A (this plane A is formed parallel to the base 3o) that is imaginary parallel to the bottom surface of the cassette 26 and along the tape path, and its width direction is perpendicular to the reference plane A. Run to. Next, the tape 31 is bent downward by the inclined post 21 at a predetermined angle α with respect to the reference plane A, and at a distance L1 from the inclined post 21, the tape 31 is bent downward at the reference plane A.
It is fed into the rotating drum 32 from an inlet Q set at a position lower than the height Hl. The fed tape 31 is wound around a predetermined tape winding angle β along a lead 320 provided diagonally along the circumferential surface of the drum, and then exits at the exit R.
The direction is running. The tape 31 has an angle β/2 from the entrance Q.
The lead 320 travels at a position H lower than the reference plane A at the position where the lead 320 is wound, that is, at the center point P located exactly at the midpoint of the tape winding angle range β from the tape population Q to the exit R of the lead 320.

This means that the tape path provided on the circumferential surface of the rotating drum 320, that is, the position of the tape lead 320 passes through the center point P.
This means that it has moved downward in the axial direction in parallel to a position that is a distance H lower. In other words, the height of the rotating drum 32 has become lower by H along Y1lIliilK with respect to the reference plane A than before.As a result, the height of the rotating drum 32 when the tape is inserted into And the exit R will be moved in parallel to a lower position in the Y-axis direction with respect to the reference plane A than before. That is, H+
, ==J +H, H2=h2H.

On the other hand, when the tape 32 reaches the tape exit R along the lead 320 from the center point P, it passes through the exit R in exactly the same manner as described above, but in the reverse order, and reaches a position higher than the reference plane A by H2. From there, it is sent out to the inclined post 24 on the exit side in a posture inclined downward at an angle α. Then, the tape 31 is bent at a predetermined angle by the inclined post 24 and returned to the same height and attitude as the vertical post 22 on the entrance side, and then sent to the vertical post 25 on the exit side. Then tape 31
is sent from the position of the vertical post 25 along a predetermined path to the cassette head 51, through which it is wound onto the winding wheel 261. The tape 31 between the first exit post 24 and the cassette entrance 51 runs parallel to the reference plane A, and its width direction runs perpendicular to the reference plane A, as described above.

The inclination directions and angles of the respective inclination bosses) 21 and 24, the inclination angle γ of the rotary drum 32 in the X-axis direction with respect to the Y-axis, or the inclination angle θ of the tape lead 320 are the same as in the example shown in FIG. This value is set so as not to impair the above-mentioned stable tape running conditions.

In this way, there is no possibility that a gap will occur between the tape and the circumferential surface of the rotating drum and the adhesion will be impaired, and that the tape will not become twisted due to uneven stress distribution in the width direction during running. It runs smoothly and stably.

In this tape running system, the distance L1 from the entrance side inclined post 21 to the tape population Q of the rotating drum 32 is
is set to be longer than the distance L2 from the tape exit R to the inclined post 24 of the four exit rules. This will be explained with reference to FIGS. 2 and 4. Here, H+ = h t + H as mentioned above.

Since H2=h2-H, I, 1-t1×1■, /h1 -t+ x (h, +H) / hl
・・・・・・・・・ (1) I, 2-t2 xI-I2
/h2 −t2×(h2−■)/h2 ・・・・・・・・・
... (2) Since 12=l, , h2=hI,
The above formula (2) is L2 = l + X (hI p f
() / hI ・・・・・・・・・ (3)
becomes.

From formulas (1) and (3), LI = l+ × (hI −+−
n)/h, ) AlX(hI H)/hI = L
It becomes 2.

That is, from the inclined post 21 on the entrance side, the tape entrance Q'
1 is set to be longer than the distance L2 from the tape exit R to the exit side inclined post 24 by (Ll-L2). When viewed from above, it becomes as shown in Fig. 5. That is, in the figure, the loading post 2o on the artificial side is at a distance (LI) from the rotating drum 32.
L2), and the loading post 23 on the exit side is at a distance corresponding to (LIL2).
It will be placed closer to the rotating drum 32 by an amount corresponding to . Therefore, there is no longer an absolute and fixed constraint that the positions of the loading posts on the inlet side and the outlet side must be arranged in line-symmetrical positions with respect to the Y axis as in the past, and the positions of both posts are It can be arbitrarily and freely arranged in an asymmetric position with respect to the axis. In addition, as shown in FIG.
It can be shaped asymmetrically with respect to the axis. the result,
For example, as shown by the imaginary line in the figure, it is also possible to incorporate other mechanical parts into the space 60 formed after the exit-side loading post 24 that has moved close to the rotating drum 32, thereby making effective use of the space. It is possible to save space.

In the embodiment, the center point P is described as being located below the reference plane A, but it may be located above the reference plane A. In this case, in the above calculation formula, Ll>L2 in the embodiment, but this becomes <L2. Therefore, the positions of the loading posts are the same as shown in Figure 5, and their arrangement is opposite to that described above. It will be placed in a far away location. Even with this, the loading posts on the population side and the exit side can be placed asymmetrically with respect to the Y axis.
Of course.

However, as the tape runs, it traces the normal running path between the two pairs of vertical and inclined posts and the inclined rotating drum, but the size of H is too large whether it is upward or downward. In this case, a mechanism that helps the tape return to its normal running path becomes essential.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of a conventional tape running system, FIG. 2 is a schematic diagram of a conventional tape running system, and FIG. 3 is a perspective view of a tape running system according to the present invention. Fourth
The figure is also a schematic diagram, and FIG. 5 is a partial schematic plan view thereof. 32... Rotating drum, 320... Tape lead (tape path), 31...
...Tape β...Tape winding angle range P...
... Center point (position) (of the tape path), 26...
...Cassette, A...Reference plane, H...Distance by which the center point P deviates, Hl,
hl: Height from the reference plane to the tape entrance. H2, h2...Height from the reference surface to the tape exit. L,,t,... Distance from the entrance side inclined post to the tape inlet, L2 + 12... From the tape outlet to the exit (lull
Distance to oblique post, Q...Tape population, R...Tape exit, 20, 23...Loading post, 21.24
... Inclined post, 22, 25... Vertical post, α... Tape incidence and exit angle. Patent applicant Shin Nippon Electric Co., Ltd.

Claims (1)

[Claims] (1) A pair of loading devices that pull out a magnetic tape from a tape cassette and wrap it around the circumferential surface of the rotating drum, which consists of a rotating drum that tilts at a predetermined angle in a predetermined direction, an inclined post, and a vertical post placed outside the tape cassette. In a video tape recorder comprising a post, a center position P in the tape winding direction of a tape path provided at an angle on the circumferential surface of the rotating drum is located below or above a reference plane A parallel to the cassette. A tape running system for a video tape recorder, characterized in that the tape running system is deviated as shown in FIG.