JPS6163950A - Motive power transmitter - Google Patents

Abstract

PURPOSE:To simplify a mechanism for the miniaturization of a motive power transmitter by using an idler which can move within a fixed range and making use of the power generated when the idler moves in the transmission mode of revolutions to the drive power of a tension control means which works when an operation mode is changed. CONSTITUTION:A drive wheel 8 keeps a revolving torque transmitted by a capstan motor 5 at a prescribed level. A rotary arm 23 is supported pivotally by boss part 16 of the upper drive wheel 13 of the wheel 8, and a rotary idler 24 is held freely rotatably at the tip part of the arm 23. Then the arm 24 revolves in the same direction as the wheel 8 and in allowed the rotary idler gear 24 to rotatably contact with an idler gear 32 at the take-up side and the idler gear 48 of the supply side respectively. Thus the revolutions of the arm 23 are transmitted to both reel drive disks 30 and 37 at the take-up and supply sides respectively. Then a rotary lever 53, a tension control means 34 and a tension band 38 work with engagement of a rotary idler gear 46 when a tape is driven toward B in a reproduction mode. Thus the brake torque added to the disk 37 is released. Thus the mechanism is simplified for the minaturization of a motive power transmitter.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a power transmission device that can be used, for example, in a video tape recorder (hereinafter abbreviated as VTR).

Conventional configuration and its problems Conventionally, for example, VTR0 recording and playback, fast forwarding and rewinding.

To switch modes such as special regeneration, brakes, tension control means, and other operating mechanisms were operated by outputs from a cam driven by a motor, a renoid, and the like. However, when using a cam, the more modes there are, the more complicated the cam shape becomes, the cam dimensions become larger when considering pressure angles, etc., and the number of members required to transmit the output from the cam to the desired location increases. );b This leads to an increase in the number of items, an increase in costs, and a reduction in the size of the equipment.

However, although the device can be simplified by using a dedicated solenoid, it has problems such as increased cost and power consumption.

Purpose of the Invention The present invention is designed to address the above situation, and uses an idler that can move within a certain range to reduce the force generated when the idler moves during rotation transmission to the JIT when changing modes.
J<An object of the present invention is to provide a power transmission device that can be used as a driving force for members.

Structure of the Invention: A drive wheel that rotates in forward and reverse directions, a first rotating body rotatably supported on a shaft, a second rotating body that rotates while engaging with the first rotating body, and the second rotating body moving means for holding the drive wheel movably between a first position close to the driving wheel and a second position close to the driving wheel while maintaining an engagement relationship with the first rotating body; The jl, 44 movement 71 and the second
The rotation of the driving wheel is transmitted to the first rotating body via the second rotating body by rolling contact with the rotating body, and the second rotating body is moved to the second position. This system is constructed with a rotary contact means for controlling the tension/contact, and for controlling the tune, with a simple structure, instead of the conventional complicated mechanism involving levers from cams and solenoids. Since the parts can be moved, the cost can be reduced by reducing the number of parts, and the mechanism can be simplified, the device can be made smaller and thinner.

DESCRIPTION OF THE EMBODIMENTS An embodiment in which the present invention is applied to a ten/control unit of a VTR will be described below with reference to the drawings.

FIG. 1 is a plan view of the main part showing the tape running state in the forward direction of the VTR, FIG. 2 is a plan view of the main part showing the tape running state in the reverse direction, and FIG. 3 is a plan view of the main part showing the tape running state in the forward direction. FIG. 4 is a cross-sectional view of the main part showing the tape running state in the opposite direction.

In FIG. 1, a magnetic tape 3 held between a capstan shaft 1 and a pinch roller 2 is fed at a constant speed in the direction of the arrow by the rotation of the capstan shaft 1 in the opposite direction. As is well known, the magnetic tape 3 is guided in its running by being wound around the outer periphery of a tape guide drum 4 containing a rotating magnetic head for recording or reproducing video signals. The capstan shaft 1 is a capstan motor 6 that can rotate in forward and reverse directions using the capstan shaft 1 as a rotation axis.
Rotationally driven by. The capstan shaft 1 of the capstan motor S is equipped with an output pulley IJ 6 that rotates integrally with the capstan shaft 1, and the output pulley 6 rotates 1 yen output C ↓ bell 1 yen. Drive through (1 [
8. As shown in FIG. 3, the structure of the drive wheel 8 includes an input pulley 9 and a gear portion 10 for transmitting the rotational output of the output pulley 6 via a belt 7.
and 1.1; an upper drive wheel 13 which is implanted in the body 11 and is rotatable with respect to a support shaft 12; a felt 14 is bonded to the upper drive wheel 13; a gear portion 16 is formed on the outer periphery; and a boss portion 16 of the upper drive wheel 13; A lower drive wheel 1 rotatably inserted into the lower drive wheel 17, a spring member 19 for urging the felt 14 bonded to the lower drive wheel 17 against the end surface 18 of the upper drive wheel 13, a spring receiver 20, and a sliding It is composed of a moving plate 21 and a stopper 22. That is, the drive wheel 8 also plays the role of a torque limiter that keeps the rotational torque transmitted by the capstan motor S at a predetermined torque.

Incidentally, the boss portion 16 of the upper drive wheel 13 has a rotating arm 23 which is supported by the boss portion 16, and a rotary idler gear 24 is rotatably held at the tip of the rotating arm 23. and transmits the rotation of 8 during the drive.

Further, a felt 25 is bonded to the rotating arm 23, and the end face 26 of the rotary idler gear 24 biases the felt 25. Due to the friction between the outer surface 26 of the rotary idler gear 24 and the felt 25, the rotary arm 23 rotates in the same direction as the rotation direction of the drive 1 "8", thereby causing the rotation. The contact idler gear 24 is brought into contact with the take-side idler gear A 32 which is engaged with the float portion 31 of the take-up reel stand 3Q, and the rotation is transmitted to the take-up side reel stand 3o.As described above, the capstan motor S
The rotational transmission torque from the drive wheel 8 to the take-up reel stand 30 is determined by the torque limited by the torque limiter formed in the drive wheel 8 and the reduction ratio from the drive wheel 8 to the take-up reel stand 30. It is determined.

By the way, in the tape running state (3) in the forward direction, in order to keep the tension of the tape sent out from the supply reel hub 32 approximately constant regardless of the winding diameter of the tape 33 wound around the supply reel hub 32, the tension /yon control means 3
4 are arranged.

The control means 34 is a long thin metal plate 35.
a ten/yonba/do fixing member 39 for fixing one end of the tension band 38 wound around the outer periphery of the supply side reel stand 37 by bonding felt 36 to a part of the supply side reel stand 37;
The other end 40 of the tension band 38 is held rotatably, and can be rotated by a lever 41.
: #Re tennyong arm hI! Ten/Y/Bost 43 that is in the upright position and contacts the tape when running the tape in the forward direction.
and a spring member 44 biased one inch in the direction of increasing the tension of the tape, and as the tape travels in the forward direction, the tension of the tape 33 wound around the supply side reel hub 32 increases. When the winding becomes smaller and the tension of the tape sent out from the supply side reel blade 32 increases, the tension arm 42 rotates clockwise against the biasing force of the spring member 44, and Reel stand 3
Since the tension band 38 wrapped around the tape 7 loosens and the tape tension decreases, a substantially constant tape tension is maintained regardless of the tape winding diameter. A mode in which the cab stun 1 excitation 1 rotates clockwise to send out the magnetic tape 3 in the direction of arrow B, that is, in the direction of the supply reel stand 37;
For example, in reverse playback, when the capstan motor 6 is reversed and the capstan shaft 1 is rotated clockwise, the drive wheel 8 is rotated clockwise, and the rotating arm 46 is moved toward the supply side reel stand 37. The rotating idler gear 46 is rotated and engaged with the supply side idler gear 48 that is engaged with the mountain part 47 of the supply side 11-ru base 37, and the magnetic tape 3 fed in the direction of arrow B is transferred to the supply side IJ. - Wind it up using the roll stand 37. By the way, the supply side idler gear 48 is composed of a first float part 49 with a large number of teeth and a second l#L1 part 60 with a small number of teeth, and the first float part 49 is connected to the idler gear 46 with a large number of teeth. The second peak JP portion 50 meshes with the gear portion 4a of the supply side reel stand. In this way, the reduction ratio from the driving wheel 8 to the supply III IJ-ru table 37 is made larger than the reduction ratio from the driving wheel 8 to the take-up side 11-ru table 3o. Necessary for winding the magnetic tape 3 transferred in the direction of arrow A by the capstan IIQI+ 1 and the pinch roller 2 on the take-up reel hub 51 in the mode of transferring the magnetic tape 3 in the positive direction shown in FIG. In the mode of transferring the magnetic tape 3 in the opposite direction shown in FIG. 3
This is because the winding torque of the supply side reel hub 320 must be large because the tape is wound around the tape guide drum 4 and other tape guide posts during the two-way period.

By the way, the supply side idler gear 48 is movable with a shaft 52 disposed near a line connecting the middle part b of the supply side idler gear 48 and the middle part U of the supply side 11-rule base 37. A shaft 54 is installed at the end of the rotating lever 53.
The rotary lever 6 is arranged so as to be rotatable around the
The rotation amount of 3 is the same as that of the locking pin 55 installed on the board 11.
When the capstan motor 5 is reversed and the drive wheel 8 is rotated clockwise during reverse playback, the rotary idler gear 46 is regulated by a long hole 56 formed in the rotary lever 63. direction, and meshes with the supply side idler gear 48 to transmit rotation.
1111 to the idler gear 48 is rotatable around the shaft 62 of the rotary lever 53, so the supply iI! II When there is a rotational load on the lever base 37, a force f corresponding to the limiter torque by the torque limiter means formed on the drive wheel 8 acts on the end 67 of the rotation lever 53. The force F corresponding to the lever ratio with the shaft 52 of the moving lever 53 set to medium/D is I! r11+K, the end 67 of the rotating lever 53 presses the end 58 of the tension arm 42 to rotate the tension arm 42 clockwise, and the Move the tension arm 43 away from the magnetic tape 3. Therefore, when reproducing in the reverse direction, as mentioned above, the tension arm 42 rotates in the 0 and 0 direction, so the tension/7 direction band 38 wound around the supply side reel stand 37 loosens, and the tension arm 42 rotates in the zero direction. Since the brake torque applied to the reel stand 37 is released and the tension arm 43 is separated from the magnetic tape 3, the supply 11111 during reverse playback is
Since the tape winding torque of the I + - roll base 37 does not increase, the +1 limiter torque of the torque limiter formed on the drive wheel 8 is reduced, and the capstan motor 6
Since the load on the system can also be reduced, power savings can be achieved.

In this manner, the tension arm 42 can be rotated with a simple structure without requiring, for example, a cam or the like or levers interlocking therewith.

By the way, as a condition for winding the magnetic tape 3 sent out by the capstan shaft 1 onto the take-up reel hub 61 or the supply reel hub 32 with a constant torque, the diameter of the capstan shaft 1 is 4 and the number of revolutions is n, and the winding speed is as follows. If the diameter of the take-up reel hub 51 or the supply reel hub 32 is taken, the rotation speed of the take-up reel hub 51 when driven by the capstan motor 5 is N4, and the rotation speed of the supply reel hub is N2, then π・D− The reduction ratio is set so that N,>π・d−n and π・D, N2)π・d−n, and the rotational speed of the capstan shaft 1 and the driven 11 reel unit is Since the difference is absorbed by the slippage of the torque limiter, the magnetic tape 3 is wound onto the driven reel stand with a predetermined torque without slack.

In addition, when high torque is required during fast forwarding and rewinding of the tape, the taranochi gear 61 disposed on the rotary plate 6o that can freely rotate with respect to the support shaft 69 rotates in the direction of arrow C to drive the upper part of the doi. By meshing with both the gear portion 1o of the wheel 13 and the gear portion 15 of the lower drive wheel 17, the rotational output of the capstan Tanabata 5 can be directly transmitted without going through a limiter.

In this embodiment, the present invention is used for the movement of a tension control member, but it is not limited to this, and it can be used for the movement of brakes and other members without any difficulty. Not even 1.

Effects of the Invention As is clear from the above description, the present invention provides a drive TIt that rotates in forward and reverse directions, a first rotating body that is rotatably supported, and a first rotating body that rotates in engagement with the first rotating body. 2 and the second rotating body while maintaining the engagement relationship with the first rotating body! l1l (moving means movably held between a first position close to the driving car and a second position far from the driving car, and a moving means that rotates around the driving car according to the rotational direction of the driving car; and by rolling contact between the driving wheel and the second rotating body, the rotation of the driving wheel is transmitted to the first rotating body via the second rotating body, and the rotation of the driving wheel is transmitted to the first rotating body via the second rotating body. Since it is composed of a rotary contact means for moving the rotary body to the second position, it does not require a complicated mechanism from a cam or a solenoid to a lever, but can be used to control the tenotion control means and its bending member with a simple structure. This provides the excellent effects of reducing costs by reducing the number of parts, and making the device smaller and thinner by simplifying the mechanism.

[Brief explanation of drawings]

FIG. 1 is a plan view of the main part of a power transmission device according to an embodiment of the present invention, FIG. 2 is a plan view of the main part in a different shape, FIG. It is a sectional view of the same essential part in the state.

Claims (2)

[Claims] (1) A drive wheel that rotates forward and backward, and a first shaft that is rotatably supported.
a rotating body, and a second rotating body that engages with and rotates the first rotating body.
a rotating body, and the second rotating body is movable between a first position close to the driving wheel and a second position far from the driving wheel while maintaining an engagement relationship with the first rotating body. a moving means held in the drive wheel; and a moving means that moves in rotation around the drive wheel according to the rotational direction of the drive wheel, and in rotation contact between the drive wheel and the second rotating body. A power transmission device comprising a rotating contact means for transmitting rotation to the first rotating body via the second rotating body and moving the second rotating body to the second position. (2) Tension control that applies back tension torque to a supply reel stand that rotates integrally with the supply reel in order to keep the back tension of the magnetic tape supplied from the supply reel wound with the magnetic tape approximately constant. means,
Claim 1, characterized in that the magnetic tape is driven in a direction to weaken the back tension of the magnetic tape by a moving means that moves as the second rotating body moves from the first position to the second position. The power transmission device described in section.