JPS6220622B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape device such as a video tape recorder, and particularly provides a single-motor drive type magnetic tape device that has a simple structure, is easy to assemble, and is suitable for making the device thinner. .

In recent years, in order to simplify the mechanism of a magnetic tape device, as a drive mechanism for a reel stand, a drive wheel is arranged approximately equidistantly from a pair of reel stands, and the drive wheel is arranged at approximately the same distance from a pair of reel stands, and the drive wheel is rotated according to the rotational direction of the drive wheel. and 1 above
a transmission mechanism including an idler in rolling contact with one of the pair of reel stands to selectively transmit the rotation of the drive wheel to either of the pair of reel stands; A so-called two-motor mechanism, which has a motor for driving a capstan and a separate reel motor for synchronously driving the capstan, has become mainstream. This system selectively drives the reel base according to the rotational direction of the reel motor to control the tape feeding direction, so it is particularly practical for feather touch type magnetic tape devices. Since it requires two motors, a reel motor and a reel motor, it has the disadvantage of increasing costs. The present invention provides a magnetic tape device that has a simple structure and is easy to assemble, has the same functions as conventional magnetic tape devices, and can be realized at a lightweight and low cost using a single motor.

Hereinafter, the present invention will be described as a videotape recorder (hereinafter referred to as
We will also explain an example using VTR (abbreviated as VTR).

FIG. 1 is a plan view of the main parts of the VTR showing the tape running state. In the same figure, capstan shaft 1
0 and the magnetic tape 14 held between the pinch rollers 12 is fed at a constant speed in the direction of arrow A by the clockwise rotation of the capstan shaft 10. As is well known, the magnetic tape 14 is guided in its running by being wound around the outer periphery of a tape guide drum 16 containing a rotating magnetic head for recording or reproducing video signals. The capstan shaft 10 is rotationally driven by a capstan motor 18 which is capable of forward and reverse rotation and which also uses the capstan shaft 10 as a rotating shaft. The capstan shaft 10 of the capstan motor 18 is equipped with an output gear 20 that rotates together with the capstan shaft 10.

The rotation of the output gear 20 is controlled by an idler gear 21,
A drive gear 22 disposed approximately equidistantly from the supply reel stand 40 and the take-up reel stand 38 via 24.
is transmitted to. A rotary arm 26 is rotatably supported on the same axis as the drive gear 22, and at its distal end,
A large gear 28a and a small gear 28b that rotate together are rotatably held, and the large gear 28a meshes with the drive gear 22. As is well known, the rotating arm 26 is rotated in the same direction as the rotational direction of the driving gear 22 by friction means using a felt 25, and the small gear 28b is used to drive the take-up reel table drive unit 30 or the supply side reel table drive unit. The unit 32 is driven to rotate.

As can be seen from FIG. 3, the take-up reel stand drive unit 30 rotates coaxially with a lower gear 30a that meshes with a gear portion formed on the outer periphery of the supply reel stand 36. , and an upper gear 30b that meshes with the small gear 28b,
Further, the rotation of the upper gear 30b is transmitted to the lower gear 30a by a well-known friction transmission means using a felt 30c.

Since the supply side reel stand drive unit 32 has almost the same configuration, the explanation here will be omitted.

The rotation directions of the capstan shaft 10 and the drive gear 22 are opposite to each other. For example, when the capstan shaft 10 rotates clockwise in FIG. The gear 22 rotates counterclockwise to rotationally displace the rotating arm 26 in the direction of the take-up reel stand 34 as shown in FIG. 3
0b, the take-up reel stand 34 is rotated clockwise, and the magnetic tape 14 is wound onto the take-up reel hub 38.

Furthermore, in a mode in which the capstan shaft 10 rotates counterclockwise to send out the magnetic tape 14 toward the supply reel stand 36, for example, in reverse playback, the capstan motor 18 is activated as shown in FIG. When the capstan shaft 10 is reversed and rotated counterclockwise, the drive gear 22 rotates clockwise, the rotation arm 26 is rotationally displaced in the direction of the supply side reel stand 36, and the small gear 28b is rotated toward the supply side reel stand 36. It meshes with the small gear 32b of the drive unit, rotates the supply reel stand 36 counterclockwise, and winds the magnetic tape 14 fed in the direction of arrow B onto the supply reel hub 40.

As a condition for winding the magnetic tape 14 sent out by the capstan shaft 10 onto the take-up reel hub 38 or the supply reel hub 40 with a constant torque, the diameter of the capstan shaft 10 is set to d,
If the number of rotations is n, the diameter of the take-up reel hub 38 or the supply reel hub 40 is D, and the number of rotations when driven by the capstan motor 18 is N, then π・D・N>π・The reduction ratio is set so that d/n, and the capstan shaft 10
The difference in rotation speed between the magnetic tape 14 and the driven reel stand is absorbed by the sliding of the friction means of the take-up reel stand drive unit 30 or the supply side reel stand drive unit 32. It is wound onto the driven side reel stand with constant torque without slack.

As described above, according to the magnetic tape device of the present invention, operations that conventionally required multiple motors, such as VTR reverse playback, which has been in increasing demand in recent years, can now be performed using only one motor. It can be done. Further, from the capstan shaft 10 to the drive gear 22
If the rotation transmission mechanism up to and the rotation transmission mechanism from the drive gear 22 to the supply reel stand 36 or the take-up reel stand 34 are arranged on opposite sides with the drive gear 22 in between, and configured so that they do not overlap with each other, The thickness of the device can be reduced.

Furthermore, if all the rotation transmission mechanisms for driving both reel stands from the capstan shaft 10 are placed on the side of the board where the cassette is mounted, not only is it easy to automate the assembly, but it is also possible to Effects such as being able to arrange electrical components and the like close to each other can be obtained, and the overall thickness of the device can also be easily reduced.

In the above explanation, only the constant speed feed mode of the magnetic tape has been explained, but the fast feed mode of the magnetic tape can also be changed by moving the pinch roller away from the capstan shaft. Needless to say, the magnetic tape can be transferred in forward and reverse directions.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a main part showing a magnetic tape forward feeding state in an embodiment of the present invention, FIG. 2 is a main part plan view showing a magnetic tape backward feeding state in an embodiment of the invention, and FIG. FIG. 2 is a sectional view taken along the - arrow in FIG. 1; 10... Capstan shaft, 12... Pinch roller, 18... Capstan motor, 22... Drive gear, 28a... Large gear, 28b... Small gear, 3
0... Take-up side reel stand drive unit, 32... Supply side reel stand drive unit, 34... Take-up side reel stand, 36... Supply side reel stand, 38... Take-up side reel hub, 40... Supply side reel hub.

Claims (1)

[Claims] 1. A supply reel stand, a take-up reel stand, a supply intermediate wheel placed on the supply reel stand side, and a take-up intermediate wheel placed on the take-up reel stand side, which can rotate in either forward or reverse directions. a motor; a capstan shaft rotatably driven by the motor and cooperating with a pinch roller to feed the magnetic tape at a constant speed; and a drive wheel disposed on the capstan shaft side from a line connecting the centers of each of the take-up reel stands; a rotation arm that is frictionally coupled to the drive wheel and can rotate coaxially with the drive wheel; The distal end of the arm includes a rotary contact wheel that is rotatably supported so as to be connected to the drive wheel at all times, and the rotation of the drive wheel is directed to the capstan of the supply reel stand and the take-up reel stand depending on the rotational direction of the drive wheel. selective rotation transmission means capable of selectively transmitting rotation to a reel stand on the side where the shaft sends out the magnetic tape via the intermediate wheel; and a rotation direction opposite to the rotational direction of the reel stand on the winding side with respect to transport of the magnetic tape. a rotation transmission mechanism for transmitting the rotation of the capstan shaft to the drive wheel so as to be rotationally driven, the rotation transmission mechanism, the selective rotation transmission means, the supply reel stand, and the take-up reel stand; A magnetic tape device characterized in that the magnetic tape device is configured such that the two do not overlap in a plane.