JPH0127144Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pinch roller actuating device for driving tape running in video tape recorders, audio tape recorders, and the like.

Video tape recorder (hereinafter referred to as VTR)
In such a magnetic tape device, a pinch roller is pressed against a capstan, and the pressure force provides a force for transporting the magnetic tape (hereinafter referred to as tape driving force). In order to obtain stable running performance, a tape driving force that is three times or more of the maximum value of the tape tension immediately before the capstan is required. When determining the force for pressing the pinch roller against the capstan (hereinafter referred to as the pinch roller pressing force), it is necessary to take into account the above-mentioned conditions, as well as environmental conditions, changes over time, etc.

In recent years, methods have been adopted to extend the recording time of VCRs, such as slowing down the tape transport speed or making the magnetic tape thinner to increase the amount of tape that can be stored in the cassette. In order to obtain excellent performance from the magnetic tape, it is essential that the performance of the magnetic tape running system be excellent. One of the important factors that determines this running performance is the tape driving force, that is, the pinch roller pressing force.

An example of a conventional pinch roller actuating device is shown in FIG. In FIG. 1, a spindle 14 is embedded in a pinch roller lever 12 that is rotatably supported on a spindle 10, and a pinch roller 16 that is rotatably supported on the spindle 14 is attached to a capstan 18 with a spring 20.
This figure shows the state of being crimped by the tensile force of . Conventionally, one of the looped threads 22 is hung on the spindle 14, the other is hung on the measuring head 26 of the spring gauge 24, and the spring gauge 24 is urged in the direction of the arrow 27 to measure the pinch roller pressing force. It was clear. When measuring on a production line using this method, the work is subdivided into the work of hanging the thread 22 on the spindle 14, the work of hanging the thread 22 on the measuring element 26, and the work of urging the spring gauge 24 in the direction of the arrow 26. The work can be divided into the work of reading the scale 28 of the spring gauge 24. On a production line that performs mass production, the work of hanging the thread 22 described above is extremely troublesome.
It was necessary to take measurements while avoiding surrounding mechanisms, and it was difficult to take accurate measurements quickly. Additionally, there was the inconvenience that the thread had to be removed when moving on to the next task.

The present invention solves the above-mentioned conventional drawbacks and facilitates the measurement of pinch roller pressure force on the production line.
To provide a pinch roller actuating device that can sufficiently manage the pinch roller pressing force and stably obtain excellent running performance.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 2 to 7. In addition, the numbers 10 to 2 in the figure
Regarding 0, it is the same as in FIG. In the present invention, as a locking part for locking the measuring head of the pinch roller pressure measuring instrument, one end of the support shaft 14 is located at a position that does not interfere with the pinch roller 16 in a plane, as illustrated in FIG. A cutout groove 30 may be provided in the pinch roller lever 12 that supports the support shaft 14, or a convex rib 32 may be provided in the pinch roller lever 12 that supports one end of the support shaft 14 as illustrated in FIG. On the pinch roller lever 12 that supports one end of the support shaft 14,
A convex rib 32 having a concave groove 34 is provided on the other end side. Of course, the above-mentioned locking portion is not limited to a notch groove or a convex rib, but may be a hole or a recess as illustrated in FIGS. 5 and 6.
That is, FIGS. 5a and 5b are examples in which the pinch roller lever 12 is provided with a hole 36, and FIGS. 6a and 6b are examples in which the pinch roller lever 12 is provided with a recess 38.

The notch groove 30, the convex rib 32, the concave groove 3
4. Contact or engage the probe 42 of the measuring device 40 as illustrated in FIG. 7 with the hole 36 or the recess 38, and move the measuring device 40 in the direction of the arrow 44 shown in FIGS. 2 to 6. When moved to , the pointer 46 of the measuring instrument 40 swings. When the measuring instrument 40 is moved in the direction of the arrow 44 and the pinch roller 16 is separated from the capstan 18, the scale 4 indicated by the pointer 46
Read the number 8.

At this time, the notch groove 30, convex rib 32, concave groove 34, hole 36, or concave portion 38, which are the locking portions of the contact point 42, are provided at positions that do not interfere with the pinch roller 16 in a plane. , measuring head 42
will not come into contact with the pinch roller 16 and damage the pinch roller 16, nor will measurement errors occur.

In addition, each of the above-mentioned locking portions is provided so that the locking direction of the contact point 42 approximately coincides with the tangential direction of rotation of the pinch roller lever 12 at each locking portion position. The directions of the tangential lines of motion substantially match, and accurate measurements can be carried out easily and smoothly.

In addition, using the measuring device 40, the upper part of the locking part (the eighth
Even if other parts of the magnetic tape device are placed near the pinch roller lever 12, measurements can be made easily and reliably without coming into contact with them. .

Here, as shown in FIG. 8, if the distance from the center of rotation of the pinch roller lever 12 to the convex rib 32 is r, the distance to the center of rotation of the pinch roller is R, and the required pinch roller pressing force is P. ,
Value P(r) obtained by converting P into the radial position of the convex rib 32
becomes P(r)=P×R/r. For example, if r = 35 mm and R = 47.85 mm, and the pinch roller pressure force needs to be within the range of 1200 to 1400 gr, P(r) is measured and if it is within the range of 1641 to 1914 gr, then It can be confirmed that the above design conditions are met.

In this way, the scale 4 indicated by the pointer 46
The value read from 8 corresponds to the pinch roller pressure force.

Note that reading the numerical value from the scale 48 pointed to by the pointer 46 may be done by moving the measuring device 40 in the direction of the arrow 44 and when the magnetic tape (not shown) that has been running until now stops. . Alternatively, move the measuring device 40 in the direction of the arrow 44 to separate the pinch roller 16 from the capstan 18, and gradually move the pinch roller 16 away from the capstan 18.
8, and read the value on the scale 48 indicated by the pointer 46 when the magnetic tape begins to run.

As explained above, the pinch roller actuating device of the present invention applies the pinch roller pressing force to the rotating member that supports one end of the spindle that rotatably supports the pinch roller, and at a position that does not interfere with the pinch roller in a plane. A locking portion capable of locking a measuring point of a measuring instrument for measuring , is arranged in a direction in which the locking direction of the measuring point coincides with the rotation tangential direction of the rotating member at the position of the locking portion. This makes it easy to assemble, and the contact position of the contact point is determined, making it easy to measure the pinch roller pressure force on the production line, and reducing measurement errors. There is no risk of damaging the pinch roller. In this way, if the pinch roller pressure force is thoroughly managed in the production process, the tape driving force will be stabilized, which will greatly contribute to stabilizing the running performance of VTRs and other devices. be.

Note that the above-mentioned notch groove 30, convex rib 32, concave groove 34, hole 36,
The shape of the recess 38 is not limited to that shown in the figure.
It goes without saying that the pinch roller lever 12 can have any other shape and its position.
can be arbitrarily selected as long as it does not interfere with the pinch roller 16 in a plane. for example,
In FIG. 8, the locking portion may be provided at a position between the spring 20 and the support shaft 10.

[Brief explanation of the drawing]

Fig. 1 is a perspective view for explaining a conventional example and its pinch roller pressure measurement method, Figs. 2, 3, and 4 are perspective views of each embodiment of the present invention, Fig. 5a , b are a top view and a cross-sectional view of main parts of another embodiment of the present invention, FIGS. 6 a and b are a top view and a cross-sectional view of yet another embodiment of the present invention, and FIG. The front view and FIG. 8 are top views for explaining the pinch roller pressure measurement method in the embodiment of the present invention. 10... Support shaft, 12... Pinch roller lever, 14... Support shaft, 16... Pinch roller, 1
8...capstan, 20...tension spring, 30
... Notch groove, 32 ... Convex rib, 34 ... Concave groove, 36 ... Hole, 38 ... Recess, 40 ... Measuring device, 42 ... Measuring tip.

Claims (1)

[Scope of utility model registration request] a pinch roller that pinches and transfers a tape-like object in cooperation with a capstan; a support shaft that rotatably supports the pinch roller; a rotatable rotating member that supports one end of the support shaft; A pinch roller actuating device comprising a biasing means for rotationally biasing the rotary member so as to press the pinch roller against the capstan with a required pressure contact force, the pinch roller actuator comprising: A locking portion for locking a probe of a measuring device that measures the pressure force of the pinch roller against the capstan is placed in a position where it does not interfere with the capstan, and the locking direction of the probe is the rotation at the position of the locking portion. A pinch roller actuator provided in a direction that substantially coincides with the tangential direction of rotation of the member.