JPS5839575Y2 - Movable tape guide device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a movable tape guide device particularly suitable for use in an oblique scanning type magnetic recording/reproducing device.

Generally, in a diagonal scanning type magnetic recording/reproducing device (hereinafter referred to as a helical scan VTR), two tape guides are arranged close to the ram under the head in order to regulate the tape winding M on the head drum that encloses the rotating head. has been done.

Especially in SMPTEC type VTRs, the tape wraps around the head drum at an angle of 344° and wraps almost the entire circumference, so the two tape guides are very close to the head drum and close to each other. It will be placed as follows.

For example, the gap between the tape guide and the head drum is approximately 0.2
mm, the distance between the two tape guides is approximately 1.5 mm.

For this reason, it is very difficult to wind the tape around the head drum when loading the tape, which has been a major drawback of this type of conventional VTR.

The tape winding operation becomes easier if the tape guide is moved and removed from the head drum when loading the tape, but in order to maintain compatibility between VTRs, the gap between the tape guide and the head drum should be approximately ±15 μm, for example. Since high precision is required, there is a problem that the movable structure of the tape guide becomes difficult.

Therefore, conventionally, if the tape guide had a movable structure,
The disadvantages are that the parts require high precision machining, and the mechanism becomes complicated and extremely expensive.

This invention was devised to eliminate these conventional drawbacks, and its purpose was to create a movable tape guide device that uses a simple mechanism, has high positional accuracy, and can be made at low cost. It is about providing.

In order to achieve this objective, the present invention is such that a slider provided with a tape guide is movably held by a guide part, and the slider is moved against a spring by a driving means via a lever. This is what I did.

This invention will be explained in detail below with reference to the drawings.

FIG. 1 is a plan view of an embodiment of a movable tape guide device according to this invention.

In the figure, after the tape 1 is fed out from a supply reel (not shown), it is transferred to a guide roller 2a and a tape guide 3.
The tape is wound helically around the head drum 5 through the tape guide 4 and the guide roller 2b, and then wound onto the take-up reel (
(not shown).

Note that 6 is a board on which the above-mentioned traveling system parts are attached.

The base 7 is fixed onto the substrate 6 by screws 8, and the slider 1 has the tape guide 3 attached to it by screws 9.
0 is held movably in the left and right direction in FIG.

Further, 11a and 11b are guide plates respectively attached to the upper surface of the base 7 with screws 12 to prevent the slider 10 from protruding upward, and 13 is a guide plate for the base 7 mounted on the base plate 6.
guide pins 14 for accurately positioning the
is a stopper attached to the slider 10 with a screw 15 in order to prevent the slider 10 from moving in the right direction in the figure at a certain position.

Here, the position of the stopper 14 is set so that when the stopper 14 hits the side surface of the base 7 and the rightward movement of the slider 10 is stopped, the tape guide 3 maintains a predetermined gap with respect to the head drum 5. There is.

Therefore, FIG. 1 shows the tape guide 3 in the recording/reproducing position.

Although not shown in FIG. 1, a lever and driving means for driving the slider 10 are provided below the substrate 6.

Figure 2 is a partially sectional front view of the movable tape guide device;
The figure is a sectional view taken along the line ■-■ in FIG.

In the SMPTE C method, as shown in FIG. 2, the tape guide 3 on the tape supply side is close to the board 6 and the tape guide 4
The tape guide 4 on the tape winding side is arranged on the lower side and about 20wIL above this.

Therefore, it is difficult to insert the tape into the gap between the tape guide 3 and the head drum 5 on the lower side, so in this embodiment, the tape guide 3 is made movable.

The base 7 has a side plate portion 7 to form a parallel opposing wall surface.
a, 7b are formed, and this side plate part 7 a t 7
A guide plate 11a is provided on the upper surface of b so as to protrude slightly inward.
, 11b are attached.

The side plate parts 7a, 7b and the guide plates 11a, 11b constitute a guide part, and the slider 10 is housed in the guide part so as to be movable in the left-right direction in FIG. 2 so as not to wobble.

Incidentally, reference numeral 16 shown in FIG. 2 is a set screw screwed into the slider 10 in order to adjust the inclination of the tape guide 3 with respect to the head drum 5.

A hole-shaped driven engagement portion 10 is provided on the lower surface of the slider 10 that has been bent.
A is formed, and a drive engaging portion 17a provided at one end of the lever 17 is engaged with this driven engaging portion 10a with an appropriate retaining play.

On the other hand, the lever 17 is rotatably supported by a support shaft 18 loosely inserted in the center, and the slider 10 is moved along the guide portion by the rotation of the lever 170.

A convex portion 17b is formed near the other end of the lever 17.

Additionally, a retaining ring 19 is attached to the support shaft 18 to prevent the lever 17 from moving in the axial direction of the support shaft 18.

Further, the ends of springs 20a and 20b, each of which has one end fixed to a support plate or the like, are hung on the other end of the lever 17, and the biasing force of the springs 20a and 20b causes the lever 1 to
7 can be rotated clockwise in FIG.

However, when the lever 17 rotates in this way, the slider 10
Even if the slider 10 is moved, the stopper 14 hits the side surface of the base 7, so the slider 10 remains at a predetermined position.

At this time, the tape guide 3 maintains a predetermined gap with respect to the head drum 5.

Further, an eccentric site hos 22 is attached to the rotating shaft 21a of the gear motor 210, and a cam portion 23 is provided around the boss 22, and these constitute a driving means that acts as an eccentric cam.

The cam portion 23 faces the convex portion 17b of the lever 17 with a predetermined gap therebetween.

In addition, in FIG. 2, the cam portion 23 that makes an eccentric movement is located at the farthest position from the convex portion 17b.

An arm 24 is fixed to the upper surface of the boss 22 in the housing, and the position of this arm 24 is detected by photosensors 25a and 25.
b is designed to be detected.

The arm 24 is slidably moved via the lever 17 as described later.
Since the slider 10 moves in correspondence with the slider 10, these arms 24 and fort sensors 25a and 25b constitute means for detecting the position of the slider 10.

Figure 4 shows lever 17. FIG. 3 is a plan view of the driving means and the detecting means viewed from above.

Incidentally, FIG. 5 is a partially sectional front view showing a state in which the tape guide 3 is in a non-recording/reproducing position separated from the head drum 5.

Next, the operation of this device will be explained.

When the tape is rewound onto the supply reel with the tape guide 3 in the tape operating position, a tape rewind detector (not shown) is activated, and the gear motor 21 is rotated in response to its signal.

This causes the cam portion 23 and the arm 24 to rotate in the direction of arrow A shown in FIG.

The arm 24 rotates approximately 1800 times and the photo sensor 25b
When a signal is sent from the photosensor 25b, the control circuit is activated and the gear motor 21 is stopped.

On the other hand, the convex portion 17b is pushed by the cam portion 23 due to the eccentric rotation of the cam portion 23, and the lever 17 is rotated counterclockwise in FIG.

As a result, the slider 10 moves to the left in FIG. 2 due to the engagement between the drive engaging portion 17a and the driven retaining portion 10a, and the tape guide 3 comes to a stop after moving away from the head drum 5 by a sufficient distance.

FIG. 5 shows this state.

Next, after winding the tape around the head drum 5 and loading it,
When the VTR is placed in standby mode, the control circuit operates and the gear motor 21 rotates in the opposite direction.

As a result, the cam portion 23 rotates eccentrically while the convex portion 17
Move in the direction away from b.

Therefore, the lever 17 rotates clockwise in FIG. 5 due to the biasing force of the springs 20a and 20b, and the slider 10 similarly moves to the right.

Then, when the stopper 14 reaches the side surface of the base 7, the movement of the slider 10 is stopped and the state shown in FIG. 2 is again achieved.

After that, the cam part 23 further rotates, and the convex part 17b
At the same time as the arm 24 is released from the photo sensor 25a
When this reaches and a signal is sent from the photosensor 25a, the control circuit operates and the gear motor 21 stops.

Note that this control circuit and the detection means constitute a detection control means that controls the drive means according to the position of the slider.

In this case, when the cam part 23 stops, the cam part 23 is completely separated from the convex part 17b, and since there is engagement play in the drive engagement part 17a, the lever 17 is not restrained from rotating, and therefore the slider 10 is moved by the biasing force of springs 20a and 20b until the stopper 14 completely hits the side surface of the base 7.

In this embodiment, the slider 1 is
Since the driving force applied to the tape guide 3 is provided only by the springs 20a and 20b, the gear motor 21 only needs to be energized when the tape guide 3 moves, thereby saving power.

Since the lever movement by the lever 17 is used,
By making the cam portion 23 slightly eccentric with respect to the rotating shaft 21a, the amount of movement can be relatively large and the shape can be made compact.

Furthermore, since the amount of eccentricity is small, the torque of the gear motor can also be small.

In addition, since the length of the slider 10 can be made larger than the gap between the slider 10 and the guide section, the inclination of the tape guide 3 with respect to the head drum 5 is so small as to be almost negligible, and the position recovery performance is also improved. Can be done.

Furthermore, the space occupied can be reduced by forming the drive mechanism and the guide mechanism in a vertically stacked structure, and by connecting both models with a lever mechanism.

Furthermore, even if the dimensions of the slider 10 and the guide portion are designed with high precision, there is an appropriate amount of play in the engagement between the slider 10 and the lever 17, so that the operation is performed smoothly without any squeaks.

In this example, the amount of movement of the tape guide 3 is 1011 m.
When set to , tape loading becomes very easy, and the tape loading time is reduced to approximately 1/2 compared to the conventional method.

A U-shaped guide system was used to hold the twisted slider in the guide section, which increased the contact area, lowered the surface pressure, and made it easier to maintain the accuracy of each component.

Then, the gap between the slider 10 and the guide portion is approximately 10 μm.
By using stainless steel for the slider 10 and phosphor bronze for the guide part (base T and guide plates 11a, 11b), there will be no abnormalities such as wear of the guide part and drive mechanism even during 200,000 reciprocating operations. is not observed, accuracy can be maintained for a long time, and the position recovery of the tape guide 3 is 2 μ
m or less, and it was confirmed that there was no problem in terms of tape compatibility.

Although this invention was applied to the tape guide 3 in the embodiment, it can also be applied to the upper tape guide 4.

As described above, the movable tape guide device according to this invention uses a simple mechanism of reciprocating movement of the slider and movement of the lever, making it possible to maintain high positional accuracy at low cost.

Therefore, it can be particularly applied to an SMPTE C type helical scan VTR with great effects.

[Brief explanation of drawings]

Fig. 1 is a plan view of an embodiment of the movable tape guide device according to this invention, Fig. 2 is a partially sectional front view, Fig. 3 is a cross-sectional view taken along the line -■ in Fig. 2, and Fig. 4 is a lever driving means. and a plan view of the detection means, and FIG. 5 is a partially sectional front view with the tape guide in the tape non-operating position. 3...Tape guide, 7...Base,
? a, 7b...Side plate part, 10...Slider, 10a...Driven engagement part, 11a, 11
b...Guide plate, 14...Stopper, 1
7... Lever, 17a... Drive engagement portion, 17b... Convex portion, 18... Support shaft, 2
0a. 20b...Spring, 21...Gear motor, 23...Cam section, 24...Arm,
25a, 25b...Photo sensors.

Claims (1)

[Claims for Utility Model Registration] 1. A slider mounted with a tape guide and moved in parallel while being held by a guide portion, a driving means for moving the slider, a stopper for preventing the slider from moving beyond a predetermined value, and the slider A movable tape guide device comprising: detection control means for controlling the drive means according to the position of the slider; and spring means for biasing the stopper so that a predetermined pressure is applied to the stopper when the slider is blocked by the stopper. 2. The slider Ifi has a driven retaining part, the driving means is rotatably supported around a fulcrum, has a driving engagement part for engaging the driven retaining part at one end, and is driven at the other end. A movable tape guide device according to claim 1, which has a lever. 3. The guide section has a base, two walls provided parallel to and facing each other on the base, and a guide plate fixed to the top of these walls, which wraps around the slider and holds it with a wide L surface. The first scope of claims for utility model registration that has been formed
The movable tape guide device according to item 1 or item 2. 4. The movable tape guide device according to claim 2 or 3, wherein the driven retaining portion and the drive retaining portion have a predetermined engagement play. 5 Utility model registration claim Paragraph 2, in which the lever is rotated by rotating an eccentric cam that engages with the lever;
The movable tape guide device according to item 3 or 4. 6. When the slider is in a predetermined position, the eccentric cam separates from the lever and only the urging force by the spring means acts. Movable cheat guide device.