JPS6222190B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape tensile force measuring device for cassette type tape recorders (audio recorders, video recorders, etc.).

A spring-balanced meter unit consisting of a movable outer ring and a fixed inner ring and a winding frame are disposed inside the cassette case, and the continuous tape between them is stretched over the cassette opening. A measuring device designed to measure tensile force has already been filed by the present applicant (inner ring fixed type).

However, in the case of such a fixed inner ring type device, due to the difference in the initial conditions during measurement, that is, the central axis of the outer ring is inclined with respect to the central axis of the inner ring,
The condition in which the outer ring and tape are in contact with the lower inner wall of the cassette case, in other words, the frictional force between the outer ring and tape and the inner wall of the cassette case differs from measurement to measurement; Due to the frictional force with the inner wall of the casing, the outer ring does not return completely due to the elasticity of the spiral spring after measurement, causing a shift in the zero position, etc., which ultimately causes variations in the measured values. It has been recognized that the tape is easy to use, and it is difficult to accurately measure the tape tensile force unless the person measuring the tape is very skilled in its handling.

The present invention has been made in view of the above points, and aims to propose a novel tape tensile force measuring device to replace the conventional inner ring fixed type.

Hereinafter, a specific example of a tape tensile force measuring device according to the present invention will be explained with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the present invention and used to explain the measurement of tape tensile force. The measuring device of this example has each element arranged in a case similar to a general compact cassette. However, in this case, for convenience, the upper half of the cassette case is removed to show the internal structure. In the figure, 1B is the lower half of a transparent resin molded product such as polystyrene (the same applies to the upper half 1A described later), 2 is the central opening on the front side, and 3
a, 3b and 4a, 4b are openings and small windows in symmetrical positions, 5a and 5b are capstan insertion holes,
6a and 6b are guide rollers located at the front left and right corners of the cassette, 6c and 6d are inner guide pins, and a tape T (however, a tape T (however, (in this case, a tape made of polyester or the like which is not coated with a magnetic film) is stretched, and a pad 7' is also disposed within the central opening 2. In other words, although the case of the measuring device of this example is a repurposed upper and lower half of a compact cassette, when it is attached to a tape recorder, it is not mounted upside down as in the conventional case.

On the left side of the cassette, that is, on the unwinding side, there is a spiral spring to be described later, and a spring balance meter unit 9 consisting of a movable outer ring 7 and a rotatable inner ring 8, and on the winding side there is a winding ring 10 and a hub. A winding frame 12 consisting of 11 is arranged respectively, and the tape T wound around the movable outer ring 7 of the meter unit 9 is guided to the circumferential surface of the winding ring 10. When mounted on a tape recorder and fixed by operating the free inner ring 8 as described later, the tape T to be transferred by the recorder's capstan and pinch roller will cause the outer ring 7 to resist its biasing spiral spring. It will be rotated in the feeding direction, but
The angle of rotation is balanced by the pulling force on the tape, ie the driving torque generated between the capstan and the pinch roller. The inner hole of the outer ring 7 and the outer periphery of the inner ring 8 are separated by a certain gap, and a large number of steel balls 13 are interposed in this gap. 14 is a scale in g displayed on the surface of the outer ring 7, 15 is the inner ring 8
These are the guidelines established for

FIG. 2 is a rear view showing the structure of the meter unit 9 and the winding frame 12. The bottom side of the movable outer ring 7 has a circular recess 16 of a certain diameter, and inside this recess, for example, a piano wire having a required spring constant is inserted. Spiral spring 1 by
7 is disposed, the outer pair of which is engaged with a part of the inner wall of the recess, and the inner end of which is engaged with a part of the fixed inner ring 8, respectively.

In the state shown now, if the inner ring 8 of the meter unit is fixed and then torque is applied to the outer ring 7 in a clockwise direction (counterclockwise in Fig. 1), the outer ring 7 will bend the spiral spring 17 in proportion to the load torque and rotate. As mentioned above, the rotation angle is theoretically always proportional to the applied torque. In addition, the winding frame 12 of this example has a slip ring 1 around the hub 11.
0 (take-up ring), the slip means is provided with the outer periphery of the hub 11 and the take-up ring 1.
Circumferential grooves 18 and 19 corresponding to the inner circumference of the winding ring 10 are formed, and a spring 20 made of piano wire or the like is bent into a substantially square shape and inserted into the inner circumferential groove 19 of the winding ring 10. The four curved sides of the spring 20 are located within the outer circumferential groove 18 of the hub 11, so that the hub 11 and the winding ring 10 are held relative to each other, and a slipping action is achieved between the two.

By the way, as already mentioned, when such a measuring device has a fixed inner ring, when it is attached to a tape recorder and the tape tensile force is measured, there is a difference between the actual tensile force and the display scale of the meter unit 9. Errors are likely to occur mainly due to the setting of initial conditions.

As a result of various studies on this point, the inventor of the present invention found that the main cause of this problem is that in the conventional device, the inner ring 8 of the meter unit 9 is fixed to the upper and lower halves of the cassette case using pins or the like. I confirmed that there is. That is, in FIG. 1, if the tape T is now pulled out from the outer ring 7 of the meter unit 9 in the direction of the arrow a, if the inner ring 8 is fixed, the outer ring 7 will move at an angle corresponding to the tension of the tape T (less than 180° in the figure). The tape T does not rotate beyond this point, and there is almost no run-up section for the tape T. Therefore, when the tape recorder to be measured is set in a running state, if the initial load depending on the contact state between the outer ring and the tape and the inner wall of the cassette case, and the initial load based on the deviation of the zero position increases. , the rotation of the tape drive motor does not start up smoothly, and eventually the outer ring stops rotating before the tape recorder under test reaches its original drive torque, and the measurement ends, causing the measured value to be incorrect. The driving torque will be smaller than the correct one and will vary. Furthermore, it has been confirmed that during measurement, unless the tape T is run up a certain length, the displayed measured value will be lower than the actual value.

Therefore, the present invention aims to improve the various problems of the past by arranging the inner ring 8 of the meter unit 9 in a free state inside the cassette case and making it possible to stop the inner ring 8 from rotating at a desired time. This is what I did.

In the figure, 21 is a through hole in the inner ring 8, 22 is a feed-out reel shaft loosely connected to the hole, and 23 is a winding frame hub 11.
24 is a take-up reel shaft; 25 is a reel shaft engagement hole;
26 is a capstan, 26 is a pinch roller, 27 is a pinch lever, 27' is its pivot, 28 is a biasing spring, 29 and 30 are an erasing head, and green is a re-head.

First, the basic idea of the present invention is to select and operate the inner ring 8 of the meter unit 9 between a free state and a fixed state, and an example of the operating means is a cassette case as shown in FIG. Specifically, the left side of the upper surface of the upper half 1A constituting the body, facing the position of the inner ring 8 of the meter unit 9, is a pressed pin 31 with a head.
is provided so that the inner ring 8 in the free state can be stopped (fixed) from rotating by pushing the pressing pin 31. That is, in the illustrated case, the leaf spring 32 is extended from the rear edge side of the upper half 1A, and the press pin 31 is attached to the free end thereof, and this is inserted into the inside through the pin hole of the upper half to correspond to the surface of the inner ring 8. It's forcing me.

As shown in FIG. 1, an appropriate number of arcuate grooves 33 are formed on the surface of the inner ring 8, for example, at positions concentric with the through hole 21, and the lower ends of the grooves 33 are inserted into them when the pressing pins 31 are pushed. (a cross section is shown), the inner ring 8 in the free state is kept in a fixed state, and the pressing pins 31 are always biased in the direction of separation by the leaf springs 32. In FIG. 3 and an example of FIG. 4, which will be described later, parts corresponding to those in FIG.

As is already clear, the present invention operates the spring balance of this type of tape tensile force measuring device, that is, the inner ring 8 of the meter unit 9 selectively in the free and fixed states, so as not to be affected by the initial load during measurement. Then, the tape T is run by a certain length between the capstan 25 and the pinch roller 26. In other words, the tape is initially run for a short time using the capstan and pinch roller, and after the tape drive motor has sufficiently started up, the meter unit 9 is operated as a spring balance. It is possible to match the tape pull force with the readings displayed on the meter unit.

The operation of the embodiment will be explained based on the above points. Initially, when this measuring device is attached to the tape recorder to be measured, the inner ring 8 of the meter unit 9 is free, so the zero point of the scale 14 of the outer ring 7 and the inner ring 8 This is completely consistent with Guideline 15. Therefore, when the tape recorder is set to play mode and the press pin 31 is pushed, the tape T runs up a little during that time, and the tape drive motor starts to rotate sufficiently, and soon the inner ring 8 becomes fixed. The pointer 15 rotates along the scale of the outer ring 7, and finally displays the driving torque caused by the cooperation of the capstan 25 and the pinch roller 26, that is, the true tensile force applied to the tape T.

FIG. 4 is a perspective view for explaining another embodiment,
In this example, a substantially triangular undulating plate 34 made of a transparent resin material such as acrylic is arranged as a spiral structure at the rear end of the upper half 1A corresponding to the position of the meter unit 9. It has a structure in which a fitting member 35 made of a relatively elastic resin molded product is attached near the top, which is the free end. The fitting member 35 is provided with engaging protrusions 36 divided into three parts as shown in the figure, and when the undulating plate 34 is tilted forward as indicated by the arrow, each engaging protrusion 36 is inserted into the through hole 21 of the inner ring 8. The inner ring 8 is inserted (indicated by phantom lines in FIG. 1) and ends up preventing rotation of the inner ring 8 in the free state. Therefore, even with such a configuration, the true tensile force can be measured by operations similar to those in the previous example. In addition, the undulating plate 34
The reason why it is made transparent is to allow the scale of the meter unit to be seen through.

Thus, according to the present invention, most of the problems of the inner ring fixed type measuring device mentioned at the beginning can be solved, and the accuracy in measuring tape tensile force can be significantly improved, which is highly praised, and the operation is simple. This is also a big advantage.

[Brief explanation of the drawing]

Fig. 1 is a plan view for explaining the internal structure and tape tension measurement of the tape tensile force measuring device according to the present invention, Fig. 2 is a rear view of the meter unit and the winding frame, and Figs. 3 and 4. 1 is an external perspective view for explaining an embodiment of the present invention. FIG. In the figure, 1A and 1B are the upper half and lower half, 7
is an outer ring, 8 is an inner ring, 9 is a meter unit, 12 is a winding frame, 14 is a scale, 15 is a pointer, 21 is a through hole, 2
5 is a capstan, 26 is a pinch roller, 31 is a pressing pin, 32 is a leaf spring, 33 is an arcuate groove, 34 is an undulating plate, 35 is a fitting member, 36 is an engaging protrusion, and T is a tape.

Claims (1)

[Scope of Claims] 1. A spring-balanced meter unit having a movable outer ring and an inner ring and a winding frame are disposed in a cassette case, and the tape fixedly wound on the movable outer ring is guided to the winding frame. , the tape is moved to the outer wall of the cassette case for a device that applies a driving torque by the cooperation of a capstan and a pinch roller to the tape between the two, and displays and measures this tape tensile force as the amount of rotational displacement of the movable outer ring. A rotary locking means is provided that is freely supported and can be engaged with and disengaged from the inner ring, and the inner ring of the meter unit is brought into the unlocked state and locked by operating the rotational locking means from outside the cassette case. A tape tensile force measuring device configured to measure the state of the tape.