JP2805063B2 - Tape tension adjusting device for magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to a tape tension adjustment of a magnetic recording / reproducing apparatus in which the tape tension can be variably adjusted at the time of recording / reproducing (FWD) of a magnetic recording / reproducing apparatus. Related to the device. [Summary of the Invention] The present invention relates to a tape tension adjusting device for a magnetic recording / reproducing device for adjusting a tape tension (back tension) during recording / reproducing, wherein the tape tension adjusting device is provided between the distal end of a tension arm and the distal end of an operating arm. The tape tension can be variably adjusted by selectively interposing a plurality of elastic bodies depending on the type of tape, that is, the difference in the coefficient of friction μ of the tape, so that any kind of tape is stable. Tape running became possible,
It is intended to reliably prevent the occurrence of tape damage, head wear, jitter, sliding noise and the like. [Related Art] For example, a supply reel table of a video tape recorder (VTR) is supplied to a rotary head drum from a supply reel table side in order to run a stable tape and obtain a stable output from a video head. A tape tension adjusting device for applying a constant tape tension (back tension) to the tape is provided. This will be described in detail with reference to FIG. 6. Reference numeral 30 denotes a supply reel table of a video tape recorder, which is rotatably supported by a chassis 31. A band brake 32 is disposed on the outer peripheral surface of the supply reel table 30 so as to be able to freely contact and separate. One end of the band brake 32 is fixed to the chassis 31 with a screw or the like, and the other end of the band brake 32 is pivotally supported by a pin at the base thereof so that the base can swing freely. A tape guide 33 for guiding a magnetic tape (both not shown) to the drum is supported by a pin at a base end of a tension arm 34 projecting therefrom. The magnetic tape is attached to the distal end of the tension arm 34 and the distal end of the operating arm 35 whose base is pivotably supported between the supply reel table 30 and the tension arm 34 of the chassis 31 by a pin. And a tension coil spring 36 for applying a constant back tension to the spring.
The band brake 32, the tension arm 34, the operation arm 35, the tension coil spring 36 and the like constitute a tape tension adjusting device. Then, the tape tension at the time of recording / reproduction is detected via the tape guide 33 of the tension arm 34, and when the tension is strong, the tension arm 34 swings in the clockwise direction in the drawing against the tensile force of the tension coil spring 36. By moving, the braking force of the band brake 32 on the supply reel base 30 is weakened, and when the tension is weak, the tension arm 34 swings clockwise to increase the braking force of the band brake 32 on the supply reel base 30. Thus, the back tension is adjusted, and stable running of the magnetic tape is obtained. [Problems to be Solved by the Invention] However, in recent years, with the upgrading of magnetic tapes, the friction coefficient μ of the magnetic tape may vary, and the back tension may change. Like a tape (MP), a high-grade tape with a mirrored magnetic surface and base surface (often having a backcoat layer, with a higher coefficient of friction μ than non-backcoated tapes such as iron oxide tape) ), The tape tension of the high-grade tape on the tape entrance side with respect to the rotating head drum is 20 to 30% higher than that of the non-backcoat tape, so that stable tape running becomes impossible, resulting in tape damage, There was a problem that head wear, jitter, sliding noise, etc. were easily generated. SUMMARY OF THE INVENTION The present invention provides a tape tension adjusting device for a magnetic recording / reproducing apparatus capable of obtaining stable tape running with any kind of tape. [Means for Solving the Problems] A base is swingably supported on a chassis between a supply reel table and a rotary head drum of a magnetic recording / reproducing apparatus. A first tension arm protruding a tape guide for guiding, one end locked to the base end of the first tension arm, the other end locked to the chassis, and a gap between both ends. A band brake wound around the outer peripheral surface of the supply reel table to change the tape tension, and a base supported swingably on a chassis between the first tension arm and the supply reel table, while magnetic recording / reproducing is performed. The band brake is tensioned by the elastic force of an elastic body interposed between the tip end side swinging toward the supply reel table side and the tip end side of the first tension arm during recording / reproduction of the apparatus. A tape tension adjusting device for a magnetic recording / reproducing apparatus, comprising: a first operating arm; and a coaxial support shaft for supporting the first tension arm at a position separated from the base end by a predetermined distance toward the front end. And at the time of swinging in a predetermined direction, comes into contact with the first tension arm, and the swing power is applied to the first tension arm.
A second tension arm having a contact piece for transmitting to the first tension arm; and a second tension arm supported coaxially with a support shaft of the first tension arm and abutting against the first tension arm when swinging in a predetermined direction. A second operating arm having a contact piece for transmitting the oscillating power to the first operating arm, and a second operating arm provided between the distal end of the first tension arm and the distal end of the first operating arm. A first elastic body, a second elastic body provided between a distal end of the second tension arm and a distal end of the second operating arm, and a first elastic body disposed between the distal end of the second tension arm and the second elastic arm. Adding means for controlling the prohibition and release of the swing of the second tension arm and for adding the elastic force of the first and second elastic bodies according to the type of the tape; The tape tension can be modulated. Are the freely. [Operation] A plurality of elastic bodies are interposed between the distal end side of the tension arm and the distal end side of the operation arm, and the elasticity of the elastic bodies is added to enable variable adjustment. The back tension is optimally adjusted so that any tape can be run stably and tape damage, head wear, jitter, sliding noise, etc. are prevented. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. 1 to 3, reference numeral 1 denotes a supply reel base of a video tape recorder (magnetic recording / reproducing device), which is rotatably supported by a chassis 2. A band brake 3 is disposed on the outer peripheral surface of the supply reel table 1 so as to be able to freely contact and separate. One end 3a of the band brake 3 is fixed to the chassis 2 with screws 4 and the like, and the other end 3b
A bar-shape tape guide 8 for guiding a magnetic tape from the supply reel table 1 to the rotary head drum 7 at a tip 5b of a base 5a pivotally supported by the chassis 2 so as to swing freely.
A pin is pivotally supported on a base end 5c of a substantially U-shaped main tension arm 5 having an upright shape. Below the main tension arm 5 of the pin 6, a base end of a sub-tension arm 9 is pivotably supported. In the middle of the sub-tension arm 9, a pin 9a is formed to project in contact with the left side surface of the main tension arm 5 in the figure to swing the main tension arm 5 clockwise. Has a movable iron piece 12 of a hinged electromagnetic actuator 10 described later fixed thereto. The electromagnetic actuator 10 is fixed below the tip 5b of the main tension arm 5 of the chassis 2.
The electromagnetic actuator 10 has an electromagnet section 11 and a movable iron piece 12 that is attracted to and separated from the electromagnet section 11 depending on whether or not the electromagnet section 11 is excited. The electromagnet section 11 is demagnetized or excited and movable by turning on or off a detection switch 13 for detecting the type of tape (cassette) arranged between the supply reel table 1 and the take-up table (not shown) of the chassis 2. The iron piece 12 is separated or adsorbed. A base a of a main operating arm 15 is pivotally supported by a pin 16 between the supply reel base 1 of the chassis 2 and the main tension arm 5 so as to be swingable. Below the main operation arm 15 of the pin 16, a base of a sub operation arm 17 is pivotably supported. In the middle of the sub operation arm 17, a pin portion 17 that contacts the left side surface of the main operation arm 15 in the drawing and swings the main operation arm 15 in the clockwise direction is provided.
a is formed to protrude. The upper end of the pin portion 17a is linked via a link mechanism 18 to a movable iron core 20 of a plunger-type electromagnetic actuator 19. That is, the electromagnetic actuator
19 is excited during recording / playback (FWD) to move the movable core 20 backward against the elastic force of the spun ring 21,
The sub-operation arm 17 and the main operation arm 15 are caused to swing clockwise, and are demagnetized at the time of unloading so that the sub-operation arm 17 is returned by the spring 21. The sub-operation arm 17 is a lever added to reliably return the sub-tension arm 9 to a predetermined position when the video tape recorder is unloaded or stopped. Thus, between the distal end 5b of the main tension arm 5 and the distal end 15b of the main operating arm 15, and between the distal end 9b of the subtension arm 9 and the distal end 17b of the sub operating arm 17, A main extension coil spring 22 and a sub extension coil spring 23 for applying a constant back tension to the magnetic tape are interposed. These band brake 3, main tension arm 5, sub tension arm 9, main operation arm 15, sub operation arm 17, main tension coil spring 22, sub tension coil spring 23, etc. constitute a tape tension adjusting device. Incidentally, 25 is a cassette housing a coating type metal tape (MP) T _1. A metal tape detection hole 26 is provided on the bottom surface of the cassette 25 (MP). Further, coating type metal tape T ₁ has a back coat layer on the base side, a high-grade tape magnetic surface is mirror-finished. Further, 27 is a cassette housing the iron oxide tape T _2. The iron oxide tape T ₂ are a non backcoat tape, the coating-type metal tape T ₁ friction coefficient in comparison with the μ is low. According to the tape tension adjustment device of the above embodiment, the unloading state of the video tape recorder shown in FIG. 1, the recording and the metal tape T ₁ which is high-grade by being loaded cassette 25 as shown in FIG. 4 At the time of reproduction, first, when the cassette 25 is mounted in a predetermined position,
The detection switch 13 is turned on by the metal tape detection hole 26 of the cassette 25, and the subtension arm 9 is attracted to the electromagnetic actuator 10 via the movable iron piece 12 by excitation of the electromagnetic actuator 10. In this state, when loading the metal tape T _1, the link mechanism by the excitation operation of the electromagnetic actuator 19
The sub operation arm 17 and the main operation arm 15 swing clockwise about the pin 16 via the pin 18, and the main tension arm 5 swings clockwise by the tensile force of the main extension coil spring 22. This allows the main tension arm 5 to be used during recording / reproduction of the video tape recorder.
When the back tension of the metal tape T1 is detected through the tape guide 8 of FIG. ₁ , when the tension is strong, only the main tension arm 5 swings counterclockwise in FIG. When the tension is weak, the main tension arm 5 swings clockwise to move the supply reel table 1 when the tension is weak.
By braking force of the band brake 3 is strengthened against, it is possible to adapt to variable adjusted to an optimum back tension of high coefficient of friction coating type metal tape T _1, the tape running property is stabilized. Further, when recording and reproducing to indicate a low coefficient of friction iron oxide tape T ₂ in FIG. 5, first, when mounting the cassette 27 to a predetermined position by the cassette 27, the detection switch 13 is turned off And the electromagnetic actuator 10
As a result, the attracted state of the movable iron piece 12 of the subtension arm 9 and the electromagnet section 11 of the electromagnetic actuator 10 is released. From this state, when the loading of iron oxide tape T _2, the link mechanism by the excitation operation of the electromagnetic actuator 19
The sub-operation arm 17 and the main operation arm 15 swing clockwise around the pin 16 via 18, and the main tension arm 5 and the sub-tension arm 9 are moved by the tension of the main extension coil spring 22 and the sub extension coil spring 23. Swing clockwise. Thus, during recording and playback of video tape recorder, the control back tension strength eyes than when the high friction coefficient metal tape T _1, can be adjusted. That is, when the back tension of the iron oxide tape T ₂ is strong, the main tension coil spring
When the main tension arm 5 and the sub tension arm 9 swing counterclockwise in the drawing against the total tension force of the sub tension coil spring 23 and the total tension force of the sub tension coil spring 23, the braking force of the band brake 3 on the supply reel table 1 is reduced. When the tension is weak and the tension is weak, the main tension arm 5 and the sub-tension arm 9 swing clockwise to increase the braking force of the band brake 3 on the supply reel table 1, thereby causing the iron oxide tape T having a low friction coefficient to decrease. It can be adjusted and adjusted to the optimal back tension of ₂ . As described above, the tension of the tension coil springs 22 and 23 can be selected in two stages according to the coefficient of friction of the tape, and the back tension of the main tension arm 5 with respect to the tape guide 8 is controlled to suppress the variation.
Regardless of the friction coefficient of the tape, the tape tension of the tape with respect to the rotary head drum 7 can be varied according to the friction coefficient of each tape and maintained at a predetermined value.
Stable tape running is possible, and the occurrence of tape damage, head wear, jitter, sliding noise, and the like can be reliably prevented. According to the embodiment, the main tension arm 5
And the sub-tension arm 9 are provided separately, but it is needless to say that an integral tension arm may be used, and the number of tension coil springs is not limited to two. [Effect of the Invention] As described above, according to the present invention, a plurality of elastic bodies are interposed between the distal end side of the tension arm and the distal end side of the operation arm, and the elastic force of the elastic bodies is added. The tape tension can be adjusted freely, which makes it possible to stably run any kind of tape with a simple structure and reliably prevent tape damage, head wear, jitter, and sliding noise. it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a tape tension adjusting device of a magnetic recording / reproducing device showing one embodiment of the present invention, and FIG. 2 is a tape tension adjusting device using a tape having a high coefficient of friction. FIG. 3 is a plan view of a tape tension adjusting device when a tape having a low friction coefficient is used; FIG. 4 is a schematic plan view of a magnetic recording and reproducing device when a tape having a high friction coefficient is used; FIG. 5 is a schematic plan view of a magnetic recording / reproducing apparatus when a tape having a low coefficient of friction is used, and FIG. 6 is a plan view of a conventional tape tension adjusting apparatus. 1 ... supply reel stand, 2 ... chassis, 3 ... band brake, 3a ... one end, 3b ... other end, 5, 9 ... tension arm, 5b, 9b ... tip end, 15, 17 …… operating arm,
15b, 17b: Tip, 22, 23: Coil spring (elastic body)
T ₁ , T ₂ …… Tape.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-223051 (JP, A) JP-A-59-110059 (JP, A) JP-A-59-96555 (JP, A) JP-A-58-58 196648 (JP, A) JP-A-58-189855 (JP, A) JP-A-51-15409 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 15/43

Claims (1)

(57) [Claims] A first base having a base portion swingably supported on a chassis between a supply reel base and a rotary head drum of the magnetic recording / reproducing apparatus, and a tape guide projecting from the supply reel base to the rotary head drum at a leading end thereof. One end of the tension arm is locked to the base end of the first tension arm, the other end is locked to the chassis, and the both ends are wound around the outer peripheral surface of the supply reel base. A band brake for changing the tape tension, and a base part is swingably supported on a chassis between the first tension arm and the supply reel base, while a supply reel base is provided during recording / reproduction of the magnetic recording / reproducing apparatus. And a first operating arm for tensioning the band brake by the elastic force of an elastic body interposed between the distal end side of the first tension arm and the distal end side of the first tension arm. In the tape tension adjusting device of the air recording / reproducing device, the first tension arm is supported coaxially with a support shaft that supports the first tension arm at a position separated from the base end by a predetermined distance toward the front end, and the first tension arm is swung in a predetermined direction. A second tension arm having a contact piece that comes into contact with the first tension arm and transmits the swinging power to the first tension arm; and is supported coaxially with a support shaft of the first operation arm. A second operating arm having a contact piece that comes into contact with the first operating arm when swinging in a predetermined direction and transmits the swinging power to the first operating arm; A first elastic body provided between the distal end and the distal end of the first operating arm; and a second elastic body provided between the distal end of the second tension arm and the distal end of the second operating arm. An elastic body; and And a control unit provided on the distal end side of the second tension arm for controlling the prohibition and release of the swing of the second tension arm, wherein the first and second elastic members are provided in accordance with the type of the tape. A tape tension adjusting device for a magnetic recording / reproducing apparatus, comprising: an adding means for adding an elastic force of the tape tension adjusting device.