JPS601694B2 - Pinch roller crimping mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pinch roller crimping mechanism used in, for example, video tape recorders as well as tape recorders using magnetic tape as various magnetic recording media, and particularly to a pinch roller crimping mechanism for crimping a pinch roller to a capstan. The present invention relates to a pinch roller crimping mechanism that generates crimping force of the pinch roller only when necessary to save power as much as possible.

Generally, in order to enable the magnetic tape of a tape recorder to travel at a constant distance, the magnetic tape is interposed between a capstan roller that rotates by itself at a constant speed and a pinch roller that follows the capstan roller. This is accomplished by pressing a pinch roller against the magnetic tape and directly transmitting the driving force of the capstan roller to the magnetic tape.

By the way, in order to accurately transmit the rotational driving force of the capstan roller to the magnetic tape, the pressure force of the pinch roller on the capstan roller usually requires several kilograms. Conventionally,
An electromagnetic plunger is used as a mechanism for pressing the pinch roller onto the capstan roller.

but,. The drawback of this electromagnetic plunger-based pinch roller clamping mechanism is that it consumes a lot of power because it is constantly energized even when it is not necessary to press the pinch roller to the capstan roller. It was large due to the arrangement of its electromagnetic plunger, etc. The present invention has been devised in view of these conventional drawbacks.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the pinch roller attachment mechanism according to the present invention will be described below with reference to the drawings.

Figure 1 shows an outline of a preferred pinch roller crimping mechanism,
FIG. 2 shows the vicinity of the coupling mechanisms such as the drive motor and the drive shaft, and FIG. 3 shows the crimping mechanism of the pinch roller.

In these figures, numeral 1 is a board of a main body of a device such as a video tape recorder, and numeral 2 is a pinch roller that is pressed against a capstan.

This pinch roller 2 is rotatably supported on a shaft 4 provided on a U-shaped support member 3. Reference numeral 5 denotes a bearing, which allows the pinch roller 2 to rotate smoothly.

6 and 7 are connection parts, respectively, and a large number of screws 8, 8 and 9
, 9 so as to allow fine adjustment in the vertical and horizontal directions in FIG.

Fine adjustment of the connecting members 6 and 7 stabilizes the movement of the pinch roller 2 toward the magnetic tape. A pivot shaft 18 is inserted into a through hole 11 formed in the substrate 1 and is attached to the substrate 1 via a bearing 12 so as to be freely rotatable.

The connecting portion 7 of this pine support shaft 1 is fixed via a pin 13, and the connecting member 6 is fixed in the bearings 12 and 14.
, 7. The entire support member 3 and pinch roller 2 are swingable in the directions of arrows A and B in FIG. On the other hand, reference numeral 15 designates a lever to which a pinch roller 2 is attached at one end via connecting portions 6 and 7, and which rotates the pinch roller 2. As shown in FIG. Similarly to the above-mentioned pinch roller 2, etc., it can swing freely in the directions of arrows C and D in FIG. 1 about a pivot shaft 10 as a fulcrum.

This rotating lever 15 is always elastically provided in the direction of arrow E in FIG. 1 by a tension spring 17, which is a first elastic member, whose one end is fixed to the base plate 1 (see FIG. 3). Reference numeral 18 denotes a slide member movable in grooves in the directions of arrows 8 and F in FIG.

One end of this slide member 18 is inserted into a through hole 21 formed in the rotation lever 15. Further, a hole 22 is formed at the other end, and a guide pin 23 fixed to the substrate 1 is inserted into this elongated hole 22.
The slide member 18 is slidably supported by.
A coil spring 24 is a second elastic member which is wound around one end of the slide member 18, and is adapted to press the side surface of the rotating lever 15 when the slide member 18 rises in the direction F in FIG. .

Next, 25 in FIG. 2 is a drive motor fixed to the lower plate 26 with screws, etc. The rotation of this motor 25 is sequentially applied to the drive shaft 27, small pulley 28, belt 29, and large pulley 30. This rotational force is transmitted to reduce the rotational speed of the motor 25, and further, this rotational force is transmitted to a worm 34 rotatably supported between a lower plate 26 and an upper plate 31 via bearings 32 and 33.

The worm wheel 35 that meshes with this worm 34 is
This drive shaft 3 is fixed to the drive shaft 36 with a pin 37a.
6 is rotatably supported by a bearing housing 37 and a bearing 38. The rotational force of this drive shaft 36 is further applied to a driving cam 40 fixed to this drive shaft 36 via a pin 39.
transmitted to. This cam 40 is moved to the third position by the drive shaft 36.
It is rotated in the direction of arrow E in the figure. This cam 4 has an operating protrusion 41 formed to gradually increase in diameter from the center point of the drive rod 36 in a direction opposite to the rotational direction, and a similar part formed subsequent to this protrusion 41. 42. FIG. 4 shows the action of this driving cam 40. That is, FIG. 4 shows the lift △ of the driving cam 40 and the cam 40.
This driving cam 40 operates as follows.

In the stroke from G to day in Fig. 4, the coil spring 24
Without compressing the rotary lever, the cam 40 rotates the rotary lever in the direction of arrow C in FIG. ,pinch. The roller 2 is brought into light contact with the capstan roller 43. In the stroke between H and 1 in FIG.
The slide member 18 is slid by the pressure exerted by the operating protrusion 41, and the coil spring 24 is compressed (see FIG. 8), and the coil spring 24 is pressurized to the point where the maximum pressing force is generated. Next, in the stroke between 1 and L in FIG.
Even when the slide member 18 rotates, the slide member 18 does not slide roughly, and the coil spring 24 is not further compressed, maintaining a constant pressing force. As is clear from the above, almost no driving energy of the motor 25 is required in the range from G to 1, so the consumption of driving energy is extremely low. Note that the upper and lower side plates 31 and 26 are fixed with screws 44 via spacers,
Further, the side plates 31 and 26 are attached to the upper surface of the substrate 1 with screws 45. Next, 46 is a guide roller 47, 4
The magnetic tape is guided between 8, 49 and the magnetic head 50 and slides therebetween, and is slid in the direction of arrow G in FIG. 1 while being pressed between the pinch roller 2 and capstan roller 43.

The operation of the present invention having such a configuration will be explained below with reference to the drawings.

First, the drive motor 25 is rotated.

The rotational force of this motor 25 is sequentially transmitted to the drive shaft 27, the pulley 28, the belt 29, and the large pulley 30, and then this rotational force is transmitted to the worm 34 and the worm 34.
It is transmitted at a reduced speed to the worm wheel 35 that meshes with the worm wheel 35. Furthermore, this rotational force is transmitted to the four cams via the drive shaft 36, and this cam 40G also rotates in the direction of arrow E in FIG. When the cam 40 rotates, the cam follower roller 20 of the slide member 18 is pressed from below by the action of the working protrusion 41, which is formed to gradually increase its diameter. The slide member 18 slides upward in FIG. As the slide member 18 gradually rises, the coil spring 24 is compressed by the spring 18 from a length L in FIG. 7 to a length L' as shown in FIG. 8.

Note that L indicates the natural length of the coil spring 24. Therefore, assuming that the spring constant of the coil spring 24 is K, a pressing force F=K(LL') is generated in the spring 24. The pressing force F of the spring 24 causes the pinch roller 2, which has been brought into contact with the capstan roller 43, to be pressed against the capstan roller 43.

Note that up to this stage (G to H in FIG. 4), the rotary lever 15 rotates in the direction of arrow C in FIG. 1 while maintaining the natural length L of the coil spring 24. When the drive cam 40 is subsequently rotated, the operating protrusion 4 of the drive cam 40
1 slides the slide part village 18 and compresses the coil spring 24, and this compression force is transmitted to the pinch roller 2 via the rotating lever 15, the connecting members 7 and 6, and the supporting member 3, This pinch roller 2 is pressed against the capstan roller 43. The pressing force of the pinch roller 2 is generated only during the period from 1 to 1 in FIG. 4, and the energy of the motor 25 is gradually consumed by this. Since the pressing force of the cam 40 is constant at the folding portion 42 of the drive cam 40, the pressing force of the pinch roller 2 on the capstan roller 43 is also constant, and this causes the pressing force on the magnetic tape 46 to be constant. is always applied with a stable force. After the pinch roller 2 contacts the capstan roller 43 in this way,
The pressing force of the pinch roller 2 is generated for the first time.

FIG. 5 shows a timing cam 51 connected to the worm wheel 35, and as the timing cam 51 rotates, the sixth microswitch 52 is fixed to the upper plate 31.
A signal as shown in the figure is produced.

Reference numerals 53 and 54 designate switching units for switching the operation of the switch 52 to correspond to the timings M and NI of the signals shown in FIG.

This signal becomes a control signal for pressing and releasing the pinch roller 2. By the way, when the driving voltage of the motor 25 fluctuates, the driving force and overrun of the motor 25 fluctuate, and as a result, during the stroke from G to L shown in FIG.
The pressing force F of the pinch roller 2 may change due to the change in the stop position of the pinch roller 2.

FIG. 9 shows an example of a voltage stabilizing circuit for dealing with such a case. Here, 55 is a resistor, 56 is a capacitor, and the resistor 55 and capacitor 56 constitute a time constant circuit. 57 and 58 are transistors, 59 is a capacitor, 60 is a Zener diode, and 25 is a motor.

As described above, according to the present invention, since the pinch roller applies pressure to the capstan roller through the magnetic tape only after the pinch loaf comes into contact with the capstan roller, the pinch loaf can achieve the following with extremely low power consumption. It is possible to apply the pressing force of a pinch roller, and since the structure is relatively simple, it greatly contributes to making the entire device 4-type.

[Brief explanation of the drawing]

The figures are all related to the present invention; Fig. 1 is a plan view showing an overview of the pinch roller crimping mechanism, Fig. 2 is a cross-sectional view showing the vicinity of the drive motor and coupling mechanism, and Fig. 3 is a portion of the pinch roller crimping mechanism. 4 is a graph showing the operating state of the pinch roller and the cam, FIG. 5 is a side view of the timing cam, and FIG. 6 is a timing chart of the driving cam. Figures 7 and 8 show an explanation of the coil spring. Figure 7 shows the state of the coil spring before the pinch roller is attached, and Figure 8 shows the state of the coil spring when the pinch roller is pressed. are shown respectively. FIG. 9 is a circuit diagram showing an example of a voltage stabilizing circuit used in this mechanism. 1・
... Board, 2... Pinch roller, 10... Pivot shaft,
15... Rotating lever, 25... Motor, 36...
- Drive shaft, 40... Driving cam, 43... Capstan roller, 46... Magnetic tape. Figure 1 Figure 4 Figure 5 Figure 2 Figure 3 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1 A drive motor, a coupling mechanism that transmits the rotational driving force of the motor, a driving cam that is rotationally driven by the coupling mechanism, a slide member that reciprocates by the rotational drive of this driving cam, and a pinch roller at one end. and a lever that is always biased to rotate in a direction to separate the pinch roller from the capstan by a first elastic member, and a second elastic member disposed between the lever and the slide member. , the slide member linearly moves forward in response to the rotation of the drive cam to rotate the rotation lever, and after the capstan roller is brought into contact with the pinch roller, the pressing force of the second elastic member is applied. A pinch roller crimping mechanism in which the pinch roller is crimped against the capstan roller via magnetic tape.