JPS63119054A - Tape tension adding mechanism for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To suppress the increase of tape tension by detecting a tape winding completing condition with the rotation detection of a reel base and driving a mode motor and an operating means so as to weaken additional torque to the reel base. CONSTITUTION:The revolution of a supplying reel base 4 is detected by a rotation detecting device 42. It is discriminated by a discriminating circuit whether the revolution is larger or smaller than V/RM (V is tape speed and RM is a winding radius at a supplying side in a tape winding). When the revolution is smaller, a winding starting condition is decided, a standard tape traveling (PB/REC) I condition of a mode cam is held, and when the revolution is larger, a winding completing condition is decided, a mode motor 8 is driven, a mode cam is rotated and a PB/RECII condition is obtained. As the result, by respective operating members such as a cam arm and a turning lever engaged to the mode cam, the pressing force of a pad to the supplying reel base 4 is minimized and the tape tension is released.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotating drum type d-air recording/reproducing device, and particularly to a tape tension addition device suitable for small size, light weight, low cost, and anti-O-IJing characteristics. Regarding the mechanism.

[Conventional technology]

There are many patents and new works related to tension adding mechanisms for stabilizing tape tension. In particular, (1) as an example,
As described in Japanese Patent Publication No. 59-20179, there is a method of controlling the tape tension by converting the tape tension value into optical and electrical signals and changing the voltage applied to a motor directly connected to the supply and take-up reel stands. be. However, this requires a reel motor that is directly connected to the motor, which is contrary to the goal of reducing weight and cost. In addition, (as a 21st example,
As described in No. 555, there is a mechanism that generates friction torque on the reel stand itself. However, when using a fixed back tension, if a cassette is used in which the tape diameter ratio at the beginning and end of winding is 2 to 5 times, the disadvantage is that the tape tension value at the end of winding increases too much. [Problems] Conventional technology for tape tension addition mechanisms for magnetic recording and reproducing devices does not take into account the number of parts, ease of assembly, and anti-112-ring characteristics, and requires time and effort to adjust the initial settings of the tape tension. In addition, there was a problem in that external vibrations such as camera shake aggravated tape tension fluctuations.An object of the present invention is to provide a tape tension ring that is inexpensive, simple, and has improved anti-O-ring characteristics. The purpose is to provide an additional mechanism.

[Means for solving problems]

The above purpose is to detect the end of tape winding by detecting the rotation of the reel stand, and to drive the mode motor and operating means to weaken the additional torque to the reel stand, thereby achieving suppression of the increase in tape tension. .

[Effect]

The diameter of the tape wound on the cassette is detected by detecting the rotation of the reel stand, and the mode motor is driven while the tape is running. The mode motor is engaged with a mode cam that operates each mode, and a torque adjustment mechanism that makes the tension variable is engaged with the reel stand. Therefore, the tape tension can be controlled by driving the mode motor.

〔Example〕

Hereinafter, one embodiment of the present invention will be described using the first factor to FIG. 7. First, the names of the component parts will be explained, and their configurations and operations will be explained.

Figure wc1 shows a schematic plan view of a magnetic recording and reproducing apparatus based on the present invention. 1 is a drum part (the explanation of the rotating part, fixed part, and magnetic head is omitted), 2 is a chassis, 3 is a cassette, 4 is a supply reel stand, 5 is a take-up reel stand, and 6 is a , tape, 7, capstan, 8
is the mode motor, 9 is the guide a-ra, IQ, 11
is a tilting bin, 12 is a rotating a-ra, 13 is an entry side drawer a-ra, 14 is an exit side drawer a-ra, 15 is a pinch roller, 16 is a guide a-ra, 17 is a , regulation a-
1B is the guide base, 19 is the catcher 12
0 is the a-ding half-moon ring, 21 is the switching gear, 2
1' is a drive gear, 22 is a mode cam, 25 is a cam arm, 24 is a reciprocating lever, 25 is a belt, 26 is a penetration gear, 27 is a relay gear, 28 is a transmission jab, 29 is, etc. The toothed gear 30 represents the pinch a-ra arm. The parts indicated by dotted lines are placed on the back side of the shear.

First, the tape drive means will be explained.

The tape 6 wound inside the cassette 5 is attached to the guide a-ra 1.
2, 15. Tilt bins 10, 11, guide a-9,
16, 17, and 14, and about 10 in the rotating drum part 1.
It is wound at 0°, recorded and reproduced, and is driven at a constant speed by the capstan 7 and the pinch roller 15. The tape is wound by an oscillating gear 26 that meshes with the take-up reel stand 5. The oscillating gear 26 is the relay gear 2
7, and the power of the capstan 7 is transmitted to the relay gear 27 via the belt 25.

Next, the a-ding operation and mode operation will be explained. The driving force of the mode motor 8 is amplified by a reduction gear train 41 and transmitted to the mode cam 22 via a constant tooth gear 29 that changes direction by 90°.

The mode cam 22 meshes with a switching gear 21 (described later) having a toothless structure, and the switching gear 21 meshes with a half-moon ring 20.

Therefore, when the mode cam 22 rotates in the direction of arrow B, the half-moon ring 20 rotates in the direction of A. guide a-ra 9,
Guide base 18 on which inclined bins 10 and 11 are mounted
is engaged with the half-moon ring 20 via an elastic member (not shown). Therefore, the guide base 18 moves together with the half-moon ring 20, and is positioned and fixed to the catcher 19 with appropriate pressure.

When the a-loading is completed, even if the mode cam 22 rotates, power is not transmitted to the cut-off gear 21, and the switching gear 21 is held in the loading completion operation. Mode operation is performed by driving the mode motor 8 in accordance with a start signal from a mode switch (not shown) built into the mode cam 22. The mode cam 22 is provided with a plurality of cam grooves (described from FIG. 2 onwards). The cam arm 25 is configured to reciprocate in the lateral direction while being guided by a cam groove. Moreover, a cam surface 23-α is provided on the end surface of this cam arm 25.
is provided, and operation switching is performed by a mode operating member that engages with the cam surface 23-α. (The mode operating member to be engaged is not shown.) The reciprocating lever 24 has a toothed surface on one end surface, meshes with the switching gear 21, and performs reciprocating motion, allowing the pinch a-ra 15 and the output side drawer a- 14.

Next, using 1 and 2, cam arm 23 and mode cam 2.
The operation with 2 will be explained. The mode cam 22 is provided with multiple cam grooves (only one is shown in Figure 2), ETECT, UL, 5TOP, and LOATING.
,FF/REIi',L,5TOP.

(Two positions are provided in REC/PB mode)
In the above-mentioned position region, the radius of curvature of the groove is constant, and in the other regions (the absolute value of the radius between each position is different), it is a radius transition region. (However, position ■ in the REC/pB region is the radius transition region). The cam arm 23 with the pin 34 installed has a pin 54K and a cam $22-α.
The mode cam 22 is engaged in the clockwise direction (LO in the figure).
As it rotates (ADING direction), it moves to the right in the figure, but during the a-ding period, the radius of the cam groove 22-8 is constant, so it is in a stopped state. Sara K.

When the mode cam 22 rotates clockwise, the cam arm 23 moves rightward corresponding to each mode position.

The outline of the a-ding and mode operation operations has been explained above, and the structure of the mechanism will be explained below with reference to FIGS. 3 and 4. A fixed shaft 33 is installed in the chassis 2, and the mode cam 22 is freely rotatable around the fixed shaft 33. The end face of the mode cam 22 includes a toothless portion 22-b, a drive gear portion 22-C, and a cam portion 22-! It has a three-layer structure. The switching gear 21 includes a drive gear 21' and a toothless portion 31. The drive gear 21' has a rotating shaft 52K.
It is press-fitted, placed on the upper surface of the chassis 2, and meshes with the half-moon ring 20. The toothless portion 31 has a cam surface 51-
α and gear 31-b, and a rotating shaft 52 is press-fitted therein. The gear 51-6 meshes with the gear portion of the mode cam and is driven, but when facing the toothless portion 22-h of the mode cam,
The teeth cannot mesh and rotational force is not transmitted. At the same time as this switching, the cam surface 51-a of the toothless portion 31 changes to the mode cam 22-d.
It is configured to engage with and hold the switching gear 21.

Based on the basic operations of the 1-mode cam and cam arm as explained above, the torque adding mechanism will be explained using FIGS. 5, 6, and 7.

First, I will explain the part names. 35 is a fixed shaft, 36 is a rotating lever 1.37 is a tension spring, 3 is a fixed shaft, 5
9 is a rotating lever 2, and 40 is a pad. The rotary lever 1 can rotate nine times around a fixed shaft 55, and one end is biased by a tension spring 37 to engage the cam surface 26-α of the cam arm 23 at the other end. The rotary lever 39 is biased by the tension spring 57 so that the pad portion and the side surface 4-α of the supply reel stand 4 are pressed together. That is, depending on the shape of the cam surface 23-α of the cam arm 23, the pressing force of the pad against the supply reel stand 4 can be varied.

The wJ6 diagram shows 1, pB as explained in the cam pattern in Figure 2.
The operation is illustrated for the I state and the ■ state of /REC.

Now, it is assumed that the pressing force of the pad against the supply reel stand 4 in the state (■) is 'yj. Next, when the mode cam rotates clockwise and reaches the state (2), the cam arm 25 is excited to the right according to the installed cam #22-α so that the radius of curvature becomes gradually thicker.

36 of the rotating lever 1 is the cam surface 23- of the cam arm 25.
Rotate clockwise along the shape of α. As a result, the displacement of the tension spring 37 becomes smaller, and the pressing force F' of the pad against the supply reel stand 4 becomes smaller. CF>F') Next, the system of the present invention will be explained using the nest diagram. The rotation speed of the supply reel stand 4 is detected by a rotation detector 42 . (The detection method may be optical or magnetic.) When the rotation speed is detected, the rotation speed is V/R (where V is the tape speed and R is the supply side during tape winding). A discriminating circuit determines whether the radius is larger or smaller than the winding radius. If it is small, it is determined to be the start of winding state and the pB/RECI state of the mode cam is held, but if it is large, it is determined to be the end of winding state, and the mode motor 8 is driven until the region mode SF detection signal is obtained. , rotates the mode cam 22 to enter the PB/RECU state.

As a result, as described above, the cam arm 25 that engages with the mode cam 22, the rotary levers 1, 2, and other operating members reduce the pressing force of the pad against the supply reel stand 4, thereby relieving the tape back tension. .

It has a tape protection function that detects the cylinder load current and performs an unmeading operation when the tape tension becomes abnormally high.

〔Effect of the invention〕

The eighth factor is a diagram showing the effect of the present invention, which is the relationship between the tape winding radius R on the supply side and the tape tension 7 winding T? This is what is illustrated. Now, if the torque to be applied to the supply reel stand 4 is 11, the tape tension is 7N depending on the tape winding diameter.
Tj/R, < T < Ts/Rt. At the end of tape winding, the tape tension 7N becomes flat. When the tape tension 7N becomes high, tape damage is more likely to occur, and an increase in tape speed variation is promoted, resulting in performance deterioration. Currently, in order to stabilize the tape tension 7N, a mechanical servo is provided using means such as a tension tension arm, but the reliability is low in terms of the number of parts, adjustment method, and vibration resistance characteristics.

According to the present invention, it is possible to solve the above-mentioned disadvantages, and there is also an advantage that it can be achieved at low cost.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a magnetic recording nose tip device according to an embodiment of the present invention, FIG. 2 is a partial plane view of the first cause, FIG. Fig. 5 is a perspective view of the mechanical operation section, Fig. 6 is a plan view of the mechanical operation section, Fig. 7 shows an operation diagram of the present invention, and Fig. 8 shows an experimental diagram of the tape ten 7N. be. 1...Drum part 2...Chassis 3...
Cassette 4...Supply reel stand 4...Take-up reel stand 6...Tape 8...Mode motor 20...A-ding half-moon ring 21...Switching gear 21'...Movement gear 22...Mode cam 25...Cam arm 2
4... Reciprocating lever 31... Missing tooth gear 55.
58...Fixed shaft 56.59...Rotating lever 37...Tension spring 40...Pad goose 3
34 times 5 times 8 mouths

Claims (1)

[Claims] 1. In a rotating drum type magnetic recording and reproducing device in which a plurality of magnetic heads are mounted on a rotating drum, a detecting means for detecting the tape winding diameter, a torque applying means for applying frictional torque to the reel stand, and operating the applying means. It has an operating means and a mode motor that drives the operating means, and supports standard tape running (PB/
REC) and high-speed tape running (100x to 200x search), the tape winding diameter is detected by the tape winding diameter detecting means, and the torque applying means is driven by the operating means and the mode motor to vary the friction torque to the reel stand. A tape tension adding mechanism for a magnetic recording/reproducing device.