JPH056746B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a tape tension control mechanism for a magnetic recording/reproducing apparatus such as a video tape recorder that uses a magnetic tape as a recording medium.

[Background of the invention]

As is well known, in magnetic recording and reproducing devices such as video tape recorders, by applying a predetermined load torque to the supply reel of the magnetic tape,
A constant tension (tape tension) is applied to the magnetic tape supplied from the supply reel to the magnetic head to prevent sagging and the like, thereby ensuring stable running of the magnetic tape.

In order to keep the tape tension applied to the magnetic tape constant, a tape tension control mechanism is provided that detects fluctuations in the tape tension and adjusts the load torque applied to the supply reel accordingly. ing.

FIG. 4 is a plan view showing a conventional example of a video tape recorder equipped with such a tape tension control mechanism, in which 1 is a magnetic tape, 2 is a supply reel, 2' is a cassette housing, 3, 3' 4 and 4' are guide rollers, 4 and 4' are inclined pins, 5 and 5' are guide roller bases, 6 is a rotating head cylinder, 7 is a capstan, 8 is a pinch roller, 9 is a tension detection member, and 10 is a main chassis.

In the same figure, during recording and reproduction, first, a pair of guide roller bases 5, 5', on which guide rollers 3, 3' and inclined pins 4, 4' are provided,
As shown in a', each moves from the inside of the cassette housing 2' to the rotary head cylinder 6, which is provided with a head for recording and reproducing video and audio signals. Along with this, the magnetic tape 1 is pulled out from the cassette housing 2', is wound around the rotary head cylinder 6 in a spiral shape at a predetermined angle, and is regulated at a predetermined running position. Also, the tension detection member 9 is
The pinch roller 8 rotates as shown in arrow b' to contact the magnetic tape 1, and the pinch roller 8 further rotates as shown by arrow b' to press the magnetic tape 1 onto the capstan 7, driving the capstan 7 to rotate. Recording and reproduction are performed by running the magnetic tape 1 at a constant speed.

FIG. 5 is a plan view showing the tape tension control mechanism of the video tape recorder of FIG.
Indicates a state in which a recording/reproducing operation is being performed, and 12
13 is a biasing spring, 13 is a detection pin provided at one end of the tension detection member 9, 14 is a reel stand, 15 is a tension addition member, 16 is a connection portion of the tension addition member 15 to the main chassis 10, and 17 is a tension addition member. 15 and the tension detection member 9, and the parts corresponding to those in FIG. 4 are given the same reference numerals.

In the figure, during recording and reproduction, the tension detection member 9, which is rotatably supported by the support shaft 11 erected on the main chassis 10, as described above,
One end is biased to rotate in the direction of arrow C by a biasing spring 12 provided on the main chassis 10, and a detection pin 13 erected at the tip of the tension detection member 9 comes into contact with the magnetic tape 1. come into contact with

Further, one end of the tension adding member 15 wound in a U-shape around the reel stand 14 of the supply side reel 2 is
Connection pin 17 erected on tension detection member 9
The other end is rotatably supported by the main chassis 1.
It is locked to a connecting part 16 fixed at 0.

Then, as the tension detection member 9 rotates around the support shaft 11, one end of the tension addition member 15 supported by the connection pin 17 also moves, and the tension addition member 15 causes the reel stand 14 to move.
The tightening force is now variable.

Next, a tape tension control operation by the tape tension control mechanism having such a configuration will be explained.

During normal tape running, the reel stand 14 rotates while being given a predetermined load torque by tightening the tension adding member 15, and the magnetic tape 1
is supplied from the supply reel 2 with a predetermined tape tension applied by this load torque. In this case, when the tape tension applied to the magnetic tape 1 and the rotational force in the direction of arrow c applied to the tension detection member 9 by the biasing spring 12 are balanced, the detection pin 13
at a predetermined position A.

Here, when tension is applied to the magnetic tape 1 at the end of winding of the magnetic tape 1 or due to some kind of disturbance, the detection pin 13 is pressed by the magnetic tape 1 and moves, and along with this, Tape tension detection member 9 is rotated in the direction of arrow c'.

Therefore, one end of the tension adding member 15 supported by the connecting pin 17 also moves in the same direction, and the reel stand 1 is moved by the tension adding member 15.
The tightness of No. 4 is relaxed. Therefore, the load torque applied to the reel stand 14 is reduced by the amount of tension applied to the magnetic tape 1 due to the above-mentioned disturbances, and the tape tension applied to the magnetic tape 1 is reduced and kept constant.

On the other hand, when the tape tension of the magnetic tape 1 is lowered due to disturbance or the like, the tape tension detection member 9 is rotated in the direction of arrow c by the urging force of the urging spring 12, and the connecting pin 17 is rotated in the direction of arrow c. One end of the tension adding member 15 supported by is also moved in the same direction. Therefore, the amount of tightening of the reel stand 14 by the tension adding member 15 increases, and the load torque applied to the reel stand 14 increases by the amount by which the tension of the magnetic tape 1 drops due to the above-mentioned disturbance, etc. The tape tension of tape 1 decreases and remains constant.

In this way, the strength of the tape tension applied to the magnetic tape 1 is detected by the detection pin 13, and the load torque is adjusted by changing the tightening force of the reel stand 14 by the tension adding member 15.
The tape tension of the magnetic tape 1 is always kept constant.

However, in such a conventional tape tension control mechanism, the tension adding member 1 to the reel stand 14 is
Because it is difficult to increase the wrapping angle of 5,
The reel stand 14 has variations in roundness,
If it is eccentric, the tension adding member 15
There was a drawback that the contact state between the tape and the reel stand 14 fluctuated, and the tape tension could not be kept constant.

Further, the tension adding member 15 is connected to the reel stand 14.
The load torque is determined by the length of the tension member 15 when it is wound (L in the figure), but as in the past, it is difficult to increase the wrapping angle of the tension adding member 15, and if the wrapping angle is small, However, there was also a drawback that the outer diameter of the reel stand 14 had to be increased in order to obtain a predetermined load torque.

Furthermore, in modes that do not require tape tension control, such as fast-forwarding or rewinding the magnetic tape 1 or loading operation, the tape tension adding member 15 is unwound to reduce the load torque on the reel stand 14. However, in this tape tension control mechanism, this was accomplished by rotating the tension detection member 9 in the direction of arrow c'. However, in order to completely release the tension addition member 15, the tension detection member 9 must be sufficiently rotated in the direction of arrow c', which requires a special release mechanism and makes the structure complicated. Ta. In addition, in order to avoid complicating the structure, if the above-mentioned release mechanism is not provided, tape tension control is not required.
There was a drawback that load torque was applied to the reel stand 14.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks of the above-mentioned prior art,
Tape tension in an operation mode that maintains the tape tension of a magnetic tape constant even when the reel stand is eccentric or the roundness of the reel stand is uneven, and does not require the tape tension. It is an object of the present invention to provide a tape tension control mechanism that allows easy release of control.

[Summary of the invention]

In order to achieve this objective, the present invention provides the first
As the invention (Claim 1), a first fulcrum (applicable embodiment code 1) is brought into contact with a tape (applicable example code 1) and is moved in a direction perpendicular or substantially perpendicular to the tape surface in response to tension fluctuations of the tape. A tension detection member (corresponding example code 9) having a configuration that is rotatably displaced around the corresponding example code 11), and a first portion (applicable example code 17) attached to the tension detecting member. The second part (applicable example code 28) is connected to the reel stand (applicable example code 1).
4) a tension adding member (corresponding embodiment code 15) having a configuration that applies a load torque to the reel stand corresponding to the displacement of the tension detecting member by being brought into contact with the tension member; A third part (corresponding example code 50) that is continuous with the part (corresponding example code 28) and located on the opposite side of the first part
is connected to the second connection part (applicable - Example code 3
1), and a second fulcrum (applicable - Example code 1
9) and a tension addition arm (applicable example code 18) which is configured to rotate around the second connection part and displace the position of the second connection part around the second fulcrum; - The above first fulcrum of example code 9) (applicable - example code 11)
The straight line (applicable example code D) that passes through the center (applicable example code B') and the center (applicable example code B) of the first connection part (applicable example code 30) is Second fulcrum (applicable - Example code 19)
(applicable example code A) and the center of the reel stand (applicable example code 14 (applicable example code A')), and the tension adding member (applicable example code A') 15) (applicable example code 50) is the above straight line (applicable example code 50)
Two tangent lines from the center of the first connection part and the center of the first fulcrum to the outer periphery of the reel stand, which are on the reel stand (corresponding example code 14) side with respect to the example code D) The configuration is such that it is placed in an area sandwiched between the two.

As a second invention (Claim 2), the first invention is brought into contact with a tape (corresponding example code 1) and moves in a direction perpendicular or substantially perpendicular to the tape surface in response to tension fluctuations of the tape. A tension detection member (corresponding example code 9) having a configuration that is rotatably displaced around a fulcrum (corresponding example code 11), and a first portion (corresponding example code 17) attached to the tension detecting member. 1 connection part (applicable example code 30), and the second part (applicable example code 28) is connected to the reel stand (applicable example code 1)
4) a tension adding member (corresponding embodiment code 15) having a configuration that applies a load torque to the reel stand corresponding to the displacement of the tension detecting member by being brought into contact with the tension member; A third part (corresponding example code 50) that is continuous with the part (corresponding example code 28) and located on the opposite side of the first part
is connected to the second connection part (applicable - Example code 3
1), and a second fulcrum (applicable - Example code 1
9) and a tension addition arm (applicable example code 18) which is configured to rotate around the second connection part and displace the position of the second connection part around the second fulcrum; - The above first fulcrum of example code 9) (applicable - example code 11)
The straight line (applicable example code D) that passes through the center (applicable example code B') and the center (applicable example code B) of the first connection part (applicable example code 30) is Second fulcrum (applicable - Example code 19)
(applicable example code A) and the center (applicable example code A') of the reel stand (applicable example code 14), and the tension adding member (applicable example code 14). The third part (corresponding example code 50) of the line (corresponding code 15) is the straight line (corresponding code 50)
Two tangent lines from the center of the first connection part and the center of the first fulcrum to the outer periphery of the reel stand, which are on the reel stand (corresponding example code 14) side with respect to the example code D) The tension adding arm (applicable example code 18) is arranged in a region sandwiched by the tension adding member (applicable example code 1) to the straight line (applicable example code D).
5) above-mentioned third part (applicable - Example code 50)
It has a release operation arm part (applicable example code 22) in the opposite direction to the above-mentioned tension detection member ( Applicable example code 9) is the contact portion of the tension addition arm (applicable example code 18) (applicable example code 2).
5) is provided with an abutted part at a position where the tension adding arm (applicable example code 18) contacts the tension detecting member (applicable example code 9). ), the tension detection member is displaced in the direction away from the tape by the contact force, and the first connection portion (corresponding example code 30) is The tension addition arm (corresponding example code 18) is configured to be displaced toward the reel stand (corresponding example code 14), and the second connecting portion (corresponding example code 31) The first connection part of the tension detection member (corresponding to -
In conjunction with the example code 30), the second portion (applicable example code 28) of the tension adding member (applicable example code 15) is connected to the reel stand (applicable example code 14). It is configured to be displaced so as to release the wrapping.

In the configurations of the first and second inventions, the tension addition arm (corresponding example code 18)
The tension adding member (corresponding to example 19) is attached to the reel stand (corresponding to example numeral 14) by the rotation of the second connecting portion (corresponding to example numeral 31) around the fulcrum (corresponding to example numeral 19). It functions to switch the contact of reference numeral 15) into an on state or an off (released) state. In addition, with this configuration and operation, the tension addition member (corresponding example code 15) for the reel stand (corresponding example code 14)
The contact angle of the reel stand (corresponding to example code 14) can be easily set to a large value, thereby making it possible to obtain a full-circumference integral effect of the contact. Fluctuations in the contact state between the corresponding example code 14) and the tension adding member (corresponding example code 15) are suppressed, and tension fluctuations of the magnetic tape are reduced.

In addition, if tension is not added to the magnetic tape, the tension adding member (corresponding to example code 15) from the reel stand (applicable to example code 14)
This provides the effect that the tension detection member (corresponding embodiment code 9) can be easily and surely released from the magnetic tape.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1a and 2 are plan views showing an embodiment of the tape tension control mechanism according to the present invention, and FIG. 1a is a plan view showing an embodiment of the tape tension control mechanism according to the invention. FIG. 2 shows a case where tape tension control is canceled during a mode such as loading. In these figures, 18 is a tensioning arm, 19 is a support shaft, 20 is a biasing spring, 21 is a stopper, 22 is a release arm part, 23 is an arm control pin, 24 is a long groove, and 25 is a contact part. The parts corresponding to those in FIG. 5 are given the same reference numerals.

In FIG. 1a, when tape tension control such as recording and reproduction is performed, the tape tension detection member 9, which is rotationally biased by the biasing spring 12, is activated as shown in FIG. , comes into contact with the magnetic tape 1 via the detection pin 13.

On the back side of the tension detection member 9, a tension adding arm 18 is rotatably supported by a support shaft 19 erected on the main chassis 10, and a biasing spring 20 is fixed at one end to the main chassis 10.
is provided and is biased to rotate in the direction of arrow d.
Further, a releasing arm portion 22 protrudes from a part of the tension addition arm 18, and a contact portion 25 provided upright at its tip abuts against a stopper 21 that is positionably provided on the main chassis 10. , the rotation range of the tension addition arm 18 is restricted.

A tension adding member 15 is wound around the reel stand 14 of the supply reel 2 over almost the entire circumference, one end of the tension adding member 15 is rotatably supported by one end of the tension adding arm 18, and other The end is rotatably supported by the tension detection member 9 by a connecting pin 17. FIG. 1b is a diagram showing the configuration of FIG. 1a in a simplified manner to make it easier to understand, and parts corresponding to those in FIG. 1a are given the same reference numerals.

Here, each of the biasing springs 12 and 20 is designed so that the rotational biasing force applied to the tension addition arm 18 is larger than the rotational biasing force applied to the tension member 9. Even when the tension detecting member 9 rotates, the tension adding arm 18 is not affected in any way and is fixed at the above-mentioned predetermined position.

In addition, in FIG. 1a, the main chassis 10 on the back side of the tension addition arm 18 has a long groove 2.
4, and an arm control pin 23 that moves in the longitudinal direction within the long groove 24 in conjunction with an operating mechanism (not shown) is provided. Note that when performing tape tension control such as during recording and playback, the arm control 23 is located at the end of the long groove 24 and does not come into contact with the tension adding arm 18, and when releasing tension control, which will be described later, The additional arm 18 is pressed and rotated.

The operation of the tape tension control mechanism having such a structure is performed in the same manner as described in FIG. That is, the detection pin 13 detects a change in the tape tension applied to the magnetic tape 1 due to disturbance or the like, and the tension detection member 9 rotates as the detection pin 13 moves, so that the connection pin 17
One end of the tension adding member 15 supported by is also moved. By appropriately changing the tightening force applied to the reel stand 14 by the tension adding member 15, the load torque is adjusted and the tape tension of the magnetic tape 1 is controlled to be constant.

However, in this embodiment, since the tension adding arm 18 is arranged so that the tension adding member 15 is wound around almost the entire circumference of the reel stand 14, even if the reel stand 14 is eccentric, the tension adding member 15 is wound around the entire circumference. Due to the integral effect, the tape tension adding member 15
Fluctuations in the contact state between the magnetic tape 1 and the reel stand 14 are extremely reduced, and the tape tension applied to the magnetic tape 1 is kept constant compared to the conventional case.

Next, in FIG. 2, when tape tension control is canceled by fast forwarding or rewinding the magnetic tape 1, the arm control pin 23 is moved along the long groove 24 by an operation mechanism (not shown). As seen, the tensioning arm 18 is pressed and rotated in the direction of arrow d'.

Further, due to this rotation, the tension member 9 is pressed by the contact portion 25 and rotated in the direction of arrow c', and the detection pin 13 is separated from the magnetic tape 1.

Further, since both ends of the tension adding member 15 supported by the tension adding arm 18 and the tension detecting member 9 move following the above-mentioned rotation, the tension adding member 15 moves to the reel stand 14.
be completely removed from.

Therefore, no negative torque is applied to the reel stand 14, tape tension control is released, and operations such as fast forwarding and rewinding of the magnetic tape 1 can be performed smoothly.

FIG. 3 is a plan view showing another embodiment of the tape tension control mechanism according to the present invention, in which a detection pin 13 comes into contact with the magnetic surface side of the magnetic tape 1 to detect tape tension. The parts corresponding to those in FIG. 1a are given the same reference numerals.

In the figure, a tension detection member 9 rotatably supported by a support shaft 11 is urged to rotate clockwise in the drawing (hereinafter the same) by an urging spring 12, and a detection pin 13 is attached to a magnetic tape. It is in contact with 1.

The tensioning arm 18 rotatably supported by the support shaft 19 is biased to rotate counterclockwise by the biasing spring 20, and the contact portion 25 is rotated against the stopper 2.
1, its rotation range is restricted.

The tension adding member 15 is wound around almost the entire circumference of the reel stand 14 , one end of which is rotatably supported by the tension detecting member 9 via a connecting pin 17 , and the other end attached to the tip of the tension adding arm 18 . It is rotatably supported in the section.

The arm control pin 23 is the tension addition arm 1
The long groove 24 is erected from the back side of the attachment part of the biasing spring 20 of 8, and is operated by an operation mechanism (not shown).
is becoming movable.

Next, the operation of the tape tension control mechanism with such a configuration will be explained.
When the tape tension fluctuates, the detection pin 13 detects the fluctuation of the tape tension, as in the above embodiment, and as the tension detection member 9 rotates, the reel stand 1 is moved by the tension adding member 15.
4 changes, and the load torque is adjusted accordingly.

On the other hand, when tape tension control is not performed, the arm control pin 23 moves within the long groove 24 by an operating mechanism (not shown), presses the tensioning arm 18, and rotates it clockwise.

Therefore, the tension detection member 9
5 and rotates counterclockwise, and as a result, the detection pin 13 is separated from the magnetic tape 1. Further, the tension adding member 15 is connected to the reel stand 1.
4, and the application of load torque to the reel stand 14 is released.

As explained above, according to these embodiments, the tension adding member 15 can be wound around almost the entire circumference of the reel stand 14 by the tension adding arm 18, so that the tape can be wrapped around the entire circumference by the integral effect. Tension controllability is improved, and the effects of variations in roundness of the reel stand 14, peripheral runout, etc. are reduced. In addition, in modes that do not require tension control such as fast forwarding, rewinding, or loading mode, the detection pin 13 can be separated from the magnetic tape by simply rotating the tension adding arm 18, and the tension adding member 15 Since the reel can be completely removed from the reel stand 14, the structure can be simplified and the tension control can be easily released.

〔Effect of the invention〕

As explained above, according to the present invention, by increasing the winding angle of the tensioning member around the magnetic tape reel, the magnetic tape is prevented from being affected by variations in the roundness of the magnetic tape reel and its eccentricity. Since fluctuations in tape tension can be reduced over time and stable tape tension control can be performed, the magnetic tape can run smoothly.
Moreover, tape tension control is released by moving both ends of the tensioning member over a wide range in opposite directions in the circumferential direction of the magnetic tape reel. It is possible to provide a tape tension control mechanism for a magnetic recording/reproducing apparatus which allows tape tension control to be easily released and which has excellent functions except for the drawbacks of the prior art described above.

[Brief explanation of the drawing]

1a and 2 are plan views showing an embodiment of a tape tension control mechanism of a magnetic recording/reproducing apparatus according to the present invention, and FIG. 1b is a plan view showing simplified components of FIG. 1a. , FIG. 3 is a plan view showing another embodiment, FIG. 4 is a plan view showing an example of a conventional video tape recorder, and FIG. 5 is a tape tension control mechanism provided in the video tape recorder shown in FIG. FIG. 9...Tension detection member, 12, 20...Biasing spring, 13...Detection pin, 15...Tension addition member, 18...Tension addition arm.

Claims (1)

[Scope of Claims] 1. A tension detection member that is in contact with a tape and is configured to rotate around a first fulcrum in a direction perpendicular or substantially perpendicular to the tape surface in response to tension fluctuations of the tape; The part is connected to the tension detection member at a first connection part, and the second part is brought into contact with the reel stand, so that a load torque corresponding to the displacement of the tension detection member is applied to the reel stand. a second connecting portion to which a third portion continuous with the second portion of the tension adding member and located on the opposite side of the first portion is connected; a tension adding arm configured to be rotated to displace the position of the second connection part around the second fulcrum; A straight line passing through the center of the connecting portion passes between the center of the second fulcrum and the center of the reel stand, and the third portion of the tension adding member is on the reel stand side with respect to the straight line. and the center of the first connection part and the first connection part
A tape tension control mechanism for a magnetic recording/reproducing device, characterized in that the mechanism is disposed in an area sandwiched between two tangent lines from the center of a fulcrum to the outer periphery of the reel stand. 2. A tension detection member that is in contact with the tape and is configured to rotate around a first fulcrum in a direction perpendicular or substantially perpendicular to the tape surface in response to tension fluctuations of the tape, and the first portion is configured to detect the tension. a tension adding member that is coupled to the member at a first connection portion and has a configuration that applies a load torque to the reel stand corresponding to the displacement of the tension detection member by a second portion being brought into contact with the reel stand; a second connecting portion connected to a third portion that is continuous with the second portion of the tensioning member and located on the opposite side of the first portion; a tension adding arm configured to displace the position of the second connection part around the second fulcrum, passing through the center of the first fulcrum of the tension detection member and the center of the first connection part; a straight line passes between the center of the second fulcrum and the center of the reel stand, and the third portion of the tension adding member is on the reel stand side with respect to the straight line, and The tension adding arm is arranged in an area sandwiched between two tangent lines from the center of the first connection part and the center of the first fulcrum to the outer periphery of the reel stand, and the tension adding arm is arranged in the area sandwiched by two tangent lines from the center of the first connection part and the center of the first fulcrum to the outer periphery of the reel stand, and the tension adding arm The release arm has a release arm in the opposite direction to the part 3, and the release arm has a contact portion, and the tension detection member is located at a position where the contact portion of the tension addition arm comes into contact with the tension detection member. The tension detecting member is provided with an abutted portion, and in a state in which the abutting portion of the tension adding arm is in contact with the abutted portion of the tension detection member, the tension detection member is moved in a direction away from the tape by the contact force. and the first connecting portion is displaced toward the reel stand, and the tension adding arm has a configuration in which the second connecting portion is connected to the first connecting portion of the tension detecting member. Interlockingly, the second tensioning member of the tensioning member
A tape tension control mechanism for a magnetic recording and reproducing device, characterized in that the tape tension control mechanism is configured to be displaced so as to release the winding from the reel stand at the portion.