JPS5928528Y2 - Braking mechanism of magnetic recording/reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a braking mechanism for a magnetic recording/reproducing device, and more particularly to a braking mechanism that minimizes the brake torque when pulling out a tape.

BACKGROUND ART Various configurations have been proposed as braking devices for magnetic recording and reproducing devices.

What is shown in FIG. 1 is a schematic plan view of a conventional magnetic recording and reproducing device, in which a supply reel 2a disposed on a housing 1 is shown.
A band type brake 4a is pressed into contact with the brake drum 3a which is pivotally mounted at the lower part of the shaft of the brake drum 3a, one end of the band type brake is fixed to a pin 5a planted on the chassis etc., and the other end is attached to the brake lever 6a. Midpoint? a, and the brake lever 6a is forced to move using one end 23a of the brake lever as a fulcrum. That is, a plunger 8a is connected to the other end of the brake lever, and a plunger 8a is connected to the other end of the brake lever, and the plunger 8a is connected to the brake drum 3a. The pressing force is forced to be released by energizing the plunger 8a against the tensile force of the spring 9a which applies the pressing force to the brake element 4a.

On the take-up reel 2b side, parts that are the same as those on the supply side are given the same reference numerals and a suffix of b is added to omit redundant explanation. It is surrounded by the take-up reel side.

In the braking mechanism configured as described above, the plunger 8a,
When applying such a braking force, the brakes 4a and 4b are released by energizing 8b, and the brakes 4a and 4b are operated by turning the plungers 8a and ab into the "off" state. Considering its absolute value, the braking force can be determined from the moment of inertia of the reel system, the allowable tape tension during brake operation, and the allowable value of the stopping time.

Furthermore, it is necessary to provide a difference in brake torque depending on the direction of rotation.

Considering this type of brake ratio, in the case of magnetic recording and reproducing devices, the moment of inertia of the reel system changes from moment to moment depending on the amount of tape, so even if the moment of inertia of the supply or take-up reel is unbalanced, the tape may loosen. It is necessary to stop the vehicle stably.

Therefore, if the braking force is changed depending on the direction of rotation of the reel to give a brake ratio, as shown in the example in Fig. 1, the strength of the brake 4a on the supply reel 2a is stronger in the counterclockwise direction than in the clockwise direction, and In the reel 2b, since the counterclockwise direction is set to be weaker than the clockwise direction, the brake torque when pulling out the tape is generally the stronger value as described above.

Such a brake ratio is required to be about 4:1, and its value is 1
60 (Bi'・α: 401・potential temperature is common).

(However, the tape pull is 1/4 inch) In other words, when pulling out the tape, the brake torque is 1600, which is the stronger side, as mentioned above.
9. Requires a concubine.

The radius of the outermost circumference of a 10.5-inch reel fully wound with tape is 12crrL, and the pulling force is 1600g-
crIL/12crrL=133g, which is small, but the force pulled out at the innermost circumference 3CIrL of Twift is 1600. ! ?・Snoring/3CrrL = 533 g, which requires extremely large force.

If the brake torque is too large as described above, it becomes difficult to pull out the tape, impairing operability and damaging the tape.

When winding the tape onto the take-up reel from the supply reel, it is preferable to reduce the brake torque in order to easily pull out the tape.

However, the brake torque was determined by the above conditions and could not be reduced.

The present invention aims to eliminate the above-mentioned drawbacks and provides a braking mechanism that minimizes the braking torque when drawing out the tape.

The details of the present invention will be explained below with reference to FIGS. 2 to 5.

Note that the same parts as in FIG. 1 are given the same reference numerals, and redundant explanation will be omitted.

The difference from FIG. 1 is that the pins 5a of the brakes 4a, 4b are pivotally connected to the second brake levers 12a, 12b, and the fulcrum 13a
, 13b, and are pivotally connected to the chassis of the housing 1, etc., so as to be freely rotatable about them.

The springs 14a, 14b are given a biasing force that balances the brake elements 4a, 4b, and the stoppers 15a, 15b are arranged near the opposite side of the fulcrum of the second brake levers 12a, 12b. A first driving means (hereinafter referred to as a plunger) 8a of 6b, and a second driving means (hereinafter referred to as a plunger) 16a facing the mounting side of 8b.
.

16b, and further plungers 16a and 16b.

Springs 18a, 18b, 17a, 17b are arranged between the brake levers 8a, sb and the brake levers 6a, 6b.

Note that 19a, 19b, 20a, and 20b indicate stopper rings.

In contrast to the braking mechanism described above, in the present invention, the tape 10 is further moved by hand 21 to the guide roller 11a.

An operating means 22 is provided for reducing the pressing force of the brake element 4a that is in contact with the brake drum 3a when the brake drum 4a is wound onto the take-up reel 2b through the brake drum 11b.

In the case of FIG. 2, plungers 8a, 8b and 16a.

If we consider only the supply reel 2a side in this case, where both 16b are in the "on" state, there will be a moment M1 due to the force of the spring 9a against the brake lever 6a, and a moment M2 due to the force of the spring 18a on the plunger 16a side.
If the value obtained by subtracting the moment M3 due to the spring 17a on the plunger 8a side from the sum is set to be smaller than the moment M1 due to the force of the spring 9a, the brake torque will be weaker than when both plungers do not operate.

In other words, if expressed in the formula 0→〈M1+M2-M3〈Ml becomes.

Therefore, by pressing the operating means 22, the plungers 8a and 16a can be operated simultaneously. Such a circuit can be easily constructed using ordinary means.

In order to more easily understand the present invention, a case in which two plungers are associated with a brake will be described with reference to FIGS. 3 to 5.

That is, the two plungers $a and 16a attached to the brake lever 63 on the supply side are both in the "off" state (FIG. 3). One plunger 8a is "off" and the other plunger 1 is in the "off" state.
6a is in the "on" state (Fig. 4) One of the pumps 8a
is “on” and the other plunger 16a is “off” (
The case of Fig. 5) will be described in detail.

In the case of FIG. 3, the brake torque in the direction of drawing out the tape (direction of arrow A) is a moment of the brake lever 6a proportional to the force of the spring 9a.

(In this case, the spring 14 is
It is assumed that the spring force of a is very large.

) The pull-out force at this time is the above-mentioned 160 (Bi'・α), which is the normal tape stop state, and as the diameter of the tape reel becomes smaller, the pull-out force increases and the operability during pull-out operation is not very good. I understand.

However, it can also be used as a stop state.

Next, in the case shown in FIG. 4, when braking is applied at the end of flat unwinding of the tape 10, the biasing force of the spring 9a alone is weak, so the plunger 16a is operated to increase the braking force and shorten the time until it stops. In the case shown in FIG. 5, the spring 17a is the spring 9.
Since the spring force is stronger than a, when only the plunger 8a is operated, the brake lever 6a rotates clockwise around the fulcrum 23a, and the second brake lever 12a rotates around the fulcrum 1.
The second brake lever is rotated counterclockwise about 3a through the brake, and one end of the second brake lever comes into contact with the stopper 15a.

That is, the brake 4a can be forced into the released state and the tape can be played back or recorded.

That is, according to the present invention, two plungers 8a as shown in FIG.
, 16a can be operated at the same time, the torque at the time of tape ejection can be made extremely small, so that an operating means for facilitating tape ejection can be added to the magnetic recording/reproducing apparatus.

Furthermore, if used as shown in Figure 3, the tape can be stopped and stopped, and in the case of Figure 4, the time from the end of rewinding to the stop can be extremely shortened, and furthermore, if used as shown in Figure 5, the tape can be recorded.・Can be interpreted as a regeneration state.

In the above embodiment, the case where a band type brake is used as a brake element is described, but it is of course possible to associate two plungers or the like with a shoe lever to which a brake shoe is attached.

As described above, the present invention can extremely reduce the force required to pull out the tape from the supply reel, and has great practical effects.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a braking mechanism of a conventional magnetic recording/reproducing device, Fig. 2 is a plan view showing a braking mechanism of the present invention, and Figs. 3 to 5 are other usage modes of the braking mechanism of the present invention. FIG. 1 is a housing, 2a, 2b are supply and take-up reels, 3a, 3
b is a brake drum, 4a, 4b are brakes, 6a, 6b
, 12a, 12b are brake levers, 8a, ab,
Plungers 22 16a and 16b are operating means.

Claims (1)

[Scope of utility model registration request] a first drive means including a brake element that presses against or separates from the brake drum; a first biasing member for applying a force in a direction to press the brake drum against the brake drum; a second driving means including a second biasing member for applying a force in a direction to disengage the brake; and a direction for pressing the brake in a state in which the first and second driving means are not biased. and a third biasing member for applying a force, and an operating means for simultaneously biasing the first and second driving means, and the operating means is actuated when the tape is manually pulled out from the reel. to operate the first and second driving means, and the biasing force of the third biasing member is equal to the biasing force obtained by subtracting the biasing force of the second biasing member from the sum of the biasing forces of the second and third biasing members. A braking mechanism for a magnetic recording/reproducing device, characterized in that the braking mechanism is made smaller than the biasing force.