JPH036585B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field This invention relates to a video tape recorder (hereinafter referred to as VTR).
The present invention relates to a tape running system (referred to as ``VTR''), and particularly to a tape running system in a VTR in which a magnetic tape is wound around a rotating drum using the M loading method.

BACKGROUND TECHNOLOGY In general, most cassette-type VTR heads use a helical scan method. This helical scan method was adopted.
In the tape running system of a VTR, in order to run the tape smoothly and stably, the running position of the tape at the outlet of the supply reel and the inlet of the take-up reel is set to a reference plane (substrate) parallel to the plane formed by the bottom of the cassette. The height of the tape must be equal to the tape, the running direction must be parallel to the tape, the width direction of the tape must be perpendicular to the reference surface, and the tape must be run diagonally along the reed that is diagonally inclined on the circumferential surface of the rotating drum. Conditions are required, including that the tape can be wound and run, and that the tape should not be twisted between the guide bodies. Here, 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,
Refers to a state in which the tension distribution at each point on the cut surface is uniform and uniform.

By the way, in order to obtain this stable running, recently,
VTRs in which a magnetic tape is wound around a rotating drum using the M loading method are often used. This has a basic tape running system that includes a rotating drum that is tilted in a predetermined direction at a predetermined angle, and a pair of tilted posts on the inlet and outlet sides.
It consists of a pair of vertical posts placed on the outside of each of these slanted posts and around which the tape is wrapped at a predetermined angle. are set to satisfy the 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, the cassette containing the tape is loaded into the supply and winding roll table of the VTR.
Inclined post 1, vertical post 2 and inclined post 3
A pair of loading posts 5 and 6 provided on the inlet and outlet sides of a rotating drum consisting of a vertical post 4 and a vertical post 4 move along guide grooves (not shown) provided in the base, as shown in FIG. The tape 9 is wound around the rotating drum 10 in an M-shape and loaded along a predetermined tape running path. Next, when the tape 9 is run, as shown in FIG. Parallel to reference plane A parallel to , and its width direction is parallel to reference plane A
run perpendicular to. Then, the tape 9 is sent out at a predetermined angle from the vertical post 2 on the entrance side to the inclined post 1 on the entrance side. Next, the tape 9 is bent downward at a predetermined angle α with respect to the reference plane A at the inclined post 1, and rotated from a position a distance l ₁ away from the inclined post 1 and a height h ₁ lower than the reference plane A. It is wound around the drum 10 within the range of angle β shown in FIG. The tape 9 is wound around the drum 10 at an angle of β/2, and the lead 13 intersects with the central axis Z-Z of the drum at a point P (this point P is located on the Y axis, which will be described later, and the tape of the lead 13 is The reference plane A is located at the exact midpoint of the winding angle range β.
, that is, the height of the inlet and outlet of the supply reel and take-up reel. That is, the angle θ of the lead 13, the inclination angle γ of the rotary drum 10 in the X-axis direction with respect to the Y-axis, and the height thereof are set so that the point P coincides with the reference plane A at the same height. Thereafter, the tape 9 is applied in exactly the same manner as described above, but in reverse, symmetrically about the Y axis, along the lead 13 from a position that is a height h ₂ higher than the reference plane A and a distance l _{2 .}
It is sent out to the inclined post 3 on the exit side, which is located a distance away, in a state of being inclined downward at an angle α. 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 runs smoothly and stably without creating any gaps between the tape and the circumferential surface of the rotating drum or twisting during the run.

However, in the conventional tape running system, the distance l 1 from the inlet side inclined post 1 to the tape entrance of the rotating drum 10 is the distance l ₁ from the tape outlet to the outlet side inclined post 3.
and the height _{h 1} of the lead 13 from the reference plane A at the tape entrance is equal to the height h ₂ of the lead 13 on the exit side. In other words, the reference plane A
The heights of the leads at the tape entrance and the tape entrance are set to be vertically symmetrical and equal heights. i.e. l ₁
= l ₂ , h ₁ = h ₂ . Therefore, as shown in Figure 1, the center line passing through the center of the rotating drum and parallel to the line connecting the centers of the reel shafts of the cassette is the X axis, and the center axis passing through the center of the rotating drum and perpendicular to the X axis is the Y axis. Then, after tape loading is completed, the arrangement relationship is 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. There must be. In other words, the tape running path must be shaped symmetrically across the rotating drum. Regardless of the configuration of the VTR, this means that the loading posts must be arranged symmetrically with respect to the Y axis, and the tape paths at the entrance and exit sides of the rotating drum must be symmetrical. This results in being bound by fixed conditions that do not occur. Therefore, due to the design of the VTR,
The design conditions are extremely restricted, such as
Depending on the configuration of the VTR, etc., you may want to make the tape path asymmetrical between the entrance and exit sides of the rotating drum, and accordingly set the left and right loading posts at asymmetrical positions at the tape loading position. It has become difficult to apply in some cases, and VTR
The degree of freedom in design is significantly impaired. Furthermore, because of the 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 loading post at an asymmetrical position with respect to the Y axis and making the tape running path formed by the loading post asymmetrical on the inlet and outlet sides of the rotating drum, Eliminating constraints on VTR design, such as path selection settings, increases the degree of design freedom, and increases the degree of freedom in selecting the tape path around the drum, making effective use of space at least by the amount of space shortened by the asymmetrical shape. Aiming for
Another objective is to provide a tape running system for a VTR that can reduce the size of the VTR.

In order to achieve this object, the present invention consists of a rotating drum that is tilted at a predetermined angle in a predetermined direction, an inclined post and a vertical post disposed on the outside thereof, and the magnetic tape is pulled out from a tape cassette and is placed around the rotating drum. In a VTR equipped with a pair of loading posts that are wound around the surface of the rotating drum, the center point P located at the midpoint of the tape winding angle range extending from the tape inlet to the tape outlet is connected to the cassette. It is formed so as to be offset downward or upward with respect to the reference plane A in parallel, and the distance from the entrance-side inclined post of the tape path formed by the loading post to the rotating drum inlet and the distance from the rotating drum outlet to the outlet The feature is that one of the distances to the side inclined posts is long and the other is short.

According to this invention, the tape is wound around the circumferential surface of the rotating drum by the left and right loading posts,
When loading, the tape path distance between the tape inlet and outlet sides of the rotating drum is made different so that one of the tape paths is shorter, and the left and right loading posts are asymmetrical between the inlet and outlet sides of the rotating drum. It can be placed in the position of Therefore, the tape running path formed on the inlet side and the outlet side of the rotating drum by the left and right loading posts can be made into an asymmetrical shape, including the selection and setting of the tape path around the rotating drum. This increases the degree of freedom in designing VTRs.

In particular, according to the present invention, a space corresponding to the shortened tape path can be created on either the inlet side or the outlet side of the rotating drum with a shortened tape path, and this space can be effectively utilized. have For example, it is possible to secure installation space for components by arranging other mechanical components close to each other in the vacant space. Furthermore, by saving the empty space created by shortening the tape path, the VTR can be made more compact.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings from FIG. 3 onwards.

FIG. 3 schematically shows the tape running system according to the present invention. In this tape running system, the tape is
It is wound around a rotating drum using the loading method as follows.

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. and into the space 260 formed at the end of the cassette 26,
The cassette 26 is loaded onto the reel stands 27 and 28. Next, when the loading of the cassette 26 is completed, the loading posts 20, 23 move along the grooves 29, 29 provided in the base 30, and the magnetic tape 3
1 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 addition,
In the figure, 33 is a back tension post that applies back tension to the tape, 34 is a full width erasing head, 35 is an impedance roller on the entrance side, 3
6 is an exit side impedance roller. Also, 3
7 is an audio 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 pinch roller for pinching the tape 31 between the capstan 39 and causing it to run in a predetermined direction. It is.

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

In this tape running system, the tape 31 is
00, the tape 31 passes from the supply reel 261 to the outlet 50 of the cassette and reaches the vertical post 22 on the inlet side.
1 is wound around the inlet side inclined post 22 at a predetermined angle. The tape 31 between the outlet 50 of the cassette and the inclined post 22 on the entrance side is connected to a reference plane A (this plane A is formed parallel to the base 30) parallel to the bottom surface of the cassette 26 and along the tape path. ), and its width direction runs perpendicular to the reference plane A. Next, the tape 31 is bent downward at a predetermined angle α with respect to the reference plane A by the inclined post 21, and is set at a position a distance L ₁ away from the inclined post 21 and a height H ₁ lower than the reference plane A. It is fed into the rotating drum 32 from the inlet Q. The fed tape 31 is wound around a predetermined tape winding angle β along a lead 320 provided diagonally along the periphery of the drum.
Drive toward exit R. The tape 31 is wound at an angle β/2 from the entrance Q, that is, at a center point P located exactly at the midpoint of the tape winding angle range β from the tape entrance Q to the exit R of the lead 320. It runs at a position H lower than A. This means that the position of the tape path provided on the circumferential surface of the rotating drum 32, that is, the tape lead 320, has shifted in parallel to a position lower by a distance H in the Y-axis direction passing through the center point P. In other words, this means that the height of the rotating drum 32 has become lower by H along the Y-axis with respect to the reference plane A than in the past. As a result, the tape inlet Q and outlet R of the rotating drum 32 are closer to the reference plane A than in the past.
This results in a parallel movement to a lower position by a distance H in the Y-axis direction. That is, H ₁ = h ₁ + H, H ₂
= _h2 -H.

On the other hand, when the tape 32 reaches the tape exit R along the lead 320 from the position of the center point P, it passes through the exit R in exactly the same manner as described above, but in the reverse order, and rises by a height H ₂ with respect to the reference plane A. It is sent out from the position 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. The tape 31 is then fed from the vertical post 25 along a predetermined path to the cassette inlet 51.
is wound up on the take-up reel 261. Then, from the inclined post 24 on the outlet side to the cassette inlet 5
The tape 31 between the tapes 1 and 1 runs parallel to the reference plane A and its width direction is perpendicular to the reference plane A, as described above.

Note that the inclination direction and angle of each of the inclined posts 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 tape lead 320
The inclination angle θ and the like are set to the same values as in the example shown in FIG. 2, 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.
In addition, the vehicle runs smoothly and stably without twisting during travel due to uneven stress distribution in the width direction.

In this tape running system, the tape entrance Q of the rotating drum 32 is
The distance L ₁ from the tape exit R to the exit-side inclined post 24 is set to be longer than the distance L ₂ from the tape exit R to the exit-side inclined post 24 . This will be explained with reference to FIGS. 2 and 4. Here, as mentioned above, H ₁ = h ₁ + H,
Since H ₂ = h ₂ - H, L ₁ = l ₁ × H ₁ / h ₁ = l ₁ × (h ₁ + H) / h ₁ ... (1) L ₂ = l ₂ × H ₂ / h ₂ = l ₂ × (h ₂ - H) / h ₂ ... (2) Since l ₂ = l ₁ , h ₂ = h ₁ , the above equation (2) becomes L ₂ = l ₁ × (h ₁ , H)/h ₁ ...(3).

From equations (1) and (3), L ₁ = l ₁ × (h ₁ + H)/h ₁ > l ₁ × (h ₁
−H)/h ₁ =L ₂ .

That is, the distance L ₁ from the inlet side inclined post 21 to the tape inlet Q is longer than the distance L ₂ from the tape outlet R to the outlet side inclined post 24 (L ₁ −
L ₂ ). When viewed from above, it becomes as shown in Fig. 5. That is,
In the figure, the loading post 20 on the inlet side is moved away from the rotating drum 32 by a distance corresponding to (L ₁ - L ₂ ), and the loading post 23 on the exit side is moved away from the rotating drum 32 by a distance corresponding to (L ₁ - L _{2 )} . ) 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 loading posts on the entrance side and the exit side must be placed in line-symmetrical positions with respect to the Y axis, as was the case in the past. The post can be arbitrarily and freely arranged asymmetrically with respect to the Y axis. Further, as shown in FIG. 5, the tape path on the inlet side and the outlet side of the rotating drum 32 can be made asymmetrical with respect to the Y axis. the result,
For example, as shown by the imaginary line in the figure, the rotating drum 32
Exit side loading post 2 moved closer to the direction
It is also possible to incorporate other mechanical parts into the space 60 formed after 4, so that the space can be used effectively and the space can be saved.

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, L ₁ >
L ₂ , but this becomes L ₁ <L ₂ . Therefore,
The position of the loading post is also opposite to that shown in Figure 5, with the loading post on the inlet side being closer to the rotating drum and the loading post on the outlet side being further away from the rotating drum. It will be placed in position. Even in this case, it goes without saying that the positions of the loading posts on the inlet side and the outlet side can be arranged asymmetrically with respect to the Y axis.

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

[Brief explanation of drawings]

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. FIG. 4 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 tape path), 2
6...Cassette, A...Reference plane, H...Distance by which the center point P deviates, _H1 , _h1 ...Height from the reference plane to the tape inlet, _H2 , _h2 ...Height from the reference plane to the tape outlet S, L ₁ , l ₁ ... Distance from the entrance side inclined post to the tape inlet, L ₂ , l ₂ ... Distance from the tape exit to the exit side inclined post, Q... Tape entrance, R... Tape exit, 20, 23... loading post, 21,
24... Inclined post, 22, 25... Vertical post, α
...tape entrance and exit angles.

Claims (1)

[Claims] 1 Equipped with a rotating drum that is tilted in a predetermined direction at a predetermined angle, and a pair of loading posts that are made up of an inclined post and a vertical post placed outside the tape cassette and that pull out the magnetic tape from the tape cassette and wrap it around the circumferential surface of the rotating drum. In the video tape recorder, 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 deviated so as to be located below or above a reference plane A parallel to the cassette, and extends from an inclined post on the entrance side of the tape path formed by the pair of loading posts to the tape entrance of the rotating drum. A tape running system characterized in that one of the distance and the distance from the tape outlet of the rotating drum to the outlet side inclined post is configured such that one is longer and the other is shorter.