JPS6139257A - Mode switching device of recording and reproducing device - Google Patents

Abstract

PURPOSE:To decrease the loss torque due to limiter torque by decreasing the limiter torque due to swinging. CONSTITUTION:The 3rd gear 11 is provided rotatably between a lower stopper fitted to a boss and the 2nd gear 5 at the peripheray of the boss of the 2nd gear 5 and the 3rd gear 11 is frictionally coupled to the 2nd geasr 5 via a friction joint 7. Further, the 3rd gear 11 meshes with a fixed rack 12. The limiter torque (friction torque) T2 between the 3rd gear 11 and the 2nd gear 5 is 2/33 of a conventional torque and the loss torque is decreased remarkably. Moreover, a turning arm 2 is turned in the arrow (b) when the 1st gear 3 is turned in the arrow (a).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a mode switching device for a recording and reproducing device such as a VTR, and more specifically, a mode switching device for a recording and reproducing device provided in a power-saving swing-type reel stand drive device. It relates to a switching device.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, in the swing type reel stand drive device used to drive the reel stand of a VTR, a limiter torque ( When the drive gear is rotating normally, this limiter torque becomes loss torque, and this amount of power is wasted.

To explain this with reference to the drawings, in FIGS. 1 and 2, reference numeral 1 is a fulcrum shaft fixed to the chassis, numeral 2 is a rotating arm rotatably attached to this fulcrum shaft 1, and numeral 3 is a pivot arm that is rotatably attached to the fulcrum shaft 1. A first gear rotatably attached to the fulcrum shaft 1 and driven to rotate in both forward and reverse directions by selection from a drive source (not shown); reference numeral 4 is a support shaft fixed to the rotating arm 2; A second gear 5 that meshes with the first gear 3 is rotatably attached to the gear 4. The upper part of the second gear 5 is regulated by a stopper 6, and a friction joint 7 is interposed between the second gear and the rotating arm 2, and the limiter torque (friction torque) is It is given.

If this limiter torque is T, the radius of the first gear 3 is r, and the radius of the second gear 5 is rl, then the second gear 5
At the limit when the rotating arm 2 does not rotate due to idle rotation, the first
Surface pressure F1 between gear 3 and second gear 5 = T+/r
It becomes +. Therefore, the torque required to rotate the rotating arm 2 is T. Then, To<Flr −T+, r/
When r+, that is, T+>Torr/r, the rotating arm 2 rotates, and conversely, when T+<Torr+/r, the second gear 5 simply rotates and the rotating arm 2 rotates -
There will be no. Note that, for example, when the rotation direction of the first gear 3 is in the direction of arrow a, the rotating direction of the rotating arm 2 is the direction indicated by the arrow.

In order for the second gear 5 to rotate without idle rotation, the limiter torque (friction torque) T of T1>Tor+/r must be applied in advance.
In this case, since r is small, the value of T must be made quite large.

On the other hand, as mentioned above, this T1 becomes a total friction loss (torque loss) when the rotating arm 2 rotates and the second gear 5 meshes with the mating gear and enters normal operation. will be wasted as wasted power.

Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a mode for a recording and reproducing apparatus equipped with an oscillating reel stand drive device in which the limiter torque (slip torque) is small and loss torque is small. The object of the present invention is to provide a switching device.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention includes a first gear that is selectively driven by a motor to rotate in both forward and reverse directions, and a rotating arm that is rotatable about the support shaft of the first gear. and,
It is rotatably attached to this rotating arm and the first
a second gear that meshes with the gear; a third gear that is coaxial with the second gear and is connected to the second gear with a required limiter torque that allows the second gear to slip; and fixed teeth that mesh with each other, so that the first gear rotates, thereby causing the second gear to mesh with the driven gear on the desired side.

With the above configuration, it is possible to reduce the limiter torque required for swinging, so it is possible to provide a mode switching device for a recording/reproducing device equipped with a swinging type reel stand drive device with less loss torque. can.

EXAMPLE An example in which the present invention is applied to an 8 mm VTR will be described below with reference to the drawings.

First, the principle of the swing mechanism according to the present invention will be explained with reference to FIGS. 3 and 4. For comparison with the conventional example,
Components having the same or the same function are given the same reference numerals to have the same configuration as much as possible, so only the different parts will be explained. That is, a third gear 11 is rotatably provided on the outer periphery of the boss of the second gear 5 between the lower stopper fixed to the boss and the second gear 5. The third gear 11 is frictionally coupled to the second gear 5 via a friction joint 7 . Further, the third gear 11 meshes with a fixed rack 12.

If the radius r2 of the third gear 11, the distance from the fulcrum shaft 1 to the rack 12 is R, and the limiter torque (friction torque) between the third gear 11 and the third gear 5 is T2, then the third The surface pressure F between the third gear 11 and the rack 12 at the limit when the gear 11 idles and the rotating arm 2 does not rotate.
z=Tz/rz.

Therefore, if the torque required to rotate the rotating arm 2 in the conventional shuttle is To, then T6 < FJ = TzR/
At T2, that is, when Tz>Tor ffi/17, the rotating arm 2 rotates, and at the opposite time, the third gear 11 only idles and the rotating arm 2 does not rotate.

Comparing this numerically, T2” 2/
Since there is a relationship of 3r+ and R#11r, Tz> (fo
r+/r ) (2/33). However, the limiter torque T+ in the conventional example is T+ 〉To r 1 /
r, the limiter torque T2 in the oscillating mechanism according to the present invention is 2/33 of the conventional example,
Lost torque will be drastically reduced. Note that the rotating arm 2 rotates when the first gear 3 is driven to rotate in the direction of arrow a.
Rotate in the direction of the arrow.

Next, an embodiment of the present invention will be described with reference to FIGS. 5 to 8. In FIG. 5, reference numeral 15 indicates a rotary head drum;
16 is a capstan, 17 is a capstan 16
This is a D capstan motor that is directly connected to the motor and capable of forward and reverse rotation. A drive pulley 19 is rotationally driven by a capstan motor 17 via a reduction gear and a timing heald 18.
It is attached to a fulcrum shaft 22 that is approximately equidistant from the take-up reel stand 20 and the supply reel stand 21. This drive pulley 19
As shown in FIG. 6, the drive wheel 23 is frictionally coupled to a drive wheel 23 fixed to a fulcrum shaft 22, and a wide first gear 24 is fixed to the upper part of the fulcrum shaft 22.

On the other hand, the fulcrum shaft 22 is supported within a hollow bearing 26 fixed on the chassis 25, and on the outer periphery of this hollow bearing,
A rotating arm 27 is attached that can freely rotate around this hollow bearing 26. A second gear 29 that meshes with the wide first gear 24 is rotatably attached to a support shaft 28 at the tip of this rotating arm 27, and a boss of this second gear 29 A third gear 30 is rotatably attached. This third gear 30 is made of magnetic plastic and is magnetically coupled to a hissing plate 31 fixed to the second gear 29, and a required magnetic limiter torque is applied therebetween to allow slipping. . Further, this third gear 30 meshes with a rack 33 provided between a pair of bins 32, as shown in FIG.

The lower end of the support shaft 28 of the rotating arm 27 is inserted into a regulation hole 36 of a brake release slider 35 that reciprocates in the directions of arrows C and d in FIG. The rotation of the rotation arm 27 is restricted by the inner surface to prevent the second gear 29 from biting into the reel base gear. and brake release slider 35
When moves back in the direction of arrow d, the tapered surface 37 of the regulating hole 36
Accordingly, the rotating arm 27 is configured to be returned to the neutral position.

As shown in FIG. 6, a rotating lever 39 is attached to the fulcrum shaft 38 and is rotated vertically by a mode switching device (not shown). 27 is configured to move up and down along the hollow bearing 26. This vertical movement causes the second gear 29 to mesh with a high-speed gear fixed to the reel stand or a constant-speed gear slipably connected to the high-speed gear.

Since the structure is as described above, the first
When the second gear 24 is rotationally driven in the direction of the arrow a from the capstan motor 17, the rotation arm 27 rotates in the direction of the arrow A, and the second gear 29 rotates in accordance with the selection of the rotation lever 39. High speed gear 40 or constant speed gear 41
When engaged, it becomes fast winding mode or normal constant speed running mode.

Note that the rotational speed of the reel stand can be switched to high speed or constant speed by speed control of the capstan motor 17.

Similarly, as shown in FIG. 8, when the first gear 24 is rotationally driven in the direction of the arrow e, the rotating arm 27 rotates in the direction of the arrow f to enter the rewind mode or the reverse constant speed running mode. .

As described in detail, according to the present invention, the limiter torque required for swinging can be reduced, so the loss torque due to this limiter torque is reduced. Therefore, it is possible to provide a power-saving mode switching device that reduces wasteful power consumption.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional example of the swinging mechanism. Figure 1 is a plan view, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, and Figures 3 to 8. The figure shows an embodiment in which the present invention is applied to an 8mm VTR. Figures 3 and 4 are principle diagrams of the oscillating mechanism according to the present invention. Figure 3 is a plan view, and Figure 4 is a plan view. Fig. 3 is a sectional view taken along the line ■-■, Fig. 5 is a schematic plan view of the VTR showing the drive device of the reel stand, Figs. FIG. 8 is a plan view showing the state in which the take-up reel stand and the supply reel stand are respectively rotated. In addition, in the symbols used in the drawings, 1, 22-------Fulcrum shaft (support shaft) 2.2
7..-1------------ Rotating arm 3, 2
t-------------1st gear 4, 28
−−−−−−−−−−−−− One support shaft 5.29−−−−
-----------Second gear 7-------
-------・-Friction joint 11.30-----Third gear 12.33----- Rack (fixed tooth) 31---- -------------His plates 40 to 43----- Driven gears.

Claims (1)

[Claims] The first rotary drive is driven in both forward and reverse directions by selection from the motor.
a rotating arm rotatable about the support shaft of the first gear; a second gear rotatably attached to the rotating arm and meshing with the first gear; a third gear coaxial with the second gear and coupled to the second gear with a required limiter torque capable of slipping;
a fixed tooth that meshes with the third gear, and the rotating arm rotates in a desired direction according to the rotational direction of the first gear, thereby causing the second gear to move to a desired side. A mode switching device for a recording/reproducing device configured to mesh with a driven gear.