JPS5912784Y2 - Tape tensile force measuring device - Google Patents

Description

[Detailed Description of the Invention] The present invention is an improved tape tensile force measuring device that can be applied to cassette-type tape recorders (audio recorders, video recorders, etc.).

A meter unit and a winding frame are arranged inside the cassette case,
The present applicant has already filed an application for a measuring device in which a continuous tape is stretched over a cassette opening and the tape tensile force is measured under play operation of a tape recorder.

FIG. 1 is a schematic perspective view showing one example, which has an external shape similar to that of a compact cassette.

In the figure, 1A is the entire measuring device, 2 is a cassette case formed by combining an upper half 3 and a lower half 4 of a transparent resin molded product such as polystyrene, 5 is a central opening on the front side, 6a, 6b, and 7a and 7b are openings and small windows in left and right symmetrical positions, 8a, 8b, 9a and 9b are capstan insertion holes and positioning holes, 10a and 10b are left and right reel shaft insertion holes, 11a and 11b are inside the casing. The guide rollers are shown at the front left and right corners of the cassette, and these are exactly the same as those of a general compact cassette. A tape (made of polyester or the like that is not coated with a magnetic film) is stretched, and a pad 12 is also disposed within the central opening 5.

In other words, the case 2 of the measuring device 1A of this example is a repurposed upper and lower half 3, 4 of a compact cassette, but when it is installed in a tape recorder, it is not installed upside down as in the conventional case.

On the left side of the cassette 2, that is, on the feeding side, a meter unit 13 having a spring-balanced configuration with a movable outer ring having a spiral spring and a fixed inner ring is arranged, and on the winding side, a winding frame 14 is arranged. (These details will be revealed in due course), meter unit 13
The structure is such that the tape T wound around the movable outer ring is guided to the circumferential surface of the winding frame 14.

Therefore, when this tape tensile force measuring device 1A is attached to a tape recorder and set to play mode, the tape T that is about to be transferred by the cap stun and pinch roller on the recorder side is However, the rotation angle is balanced by the tensile force applied to the tape, that is, the driving torque generated between the capstan and the pinch roller.

In other words, the exemplary measuring device 1A is a measuring meter designed to quantitatively see through the rotation angle of the outer ring through the transparent upper half 3 under the above-mentioned condition, and the scales, indicators, etc. for this purpose are in the meter unit. The relationship between the 13 movable outer rings and their fixed inner rings is displayed.

Incidentally, it is widely known among those skilled in the art that such measurement of tape tensile force is necessary at each stage of tape recorder design, prototyping, manufacturing lines, after-sales service, and the like.

However, when such a device 1A is attached to a tape recorder and the tape tensile force is measured, a slight error occurs in the measured value displayed.

In other words, this measurement is performed with the tape recorder in the play mode, so the erasing head, recording head, rewriting head, etc. are in contact with the surface of the above-mentioned stretch tape T (the measurement device of this example is for a normal compact cassette type tape recorder). In addition, at the recording and reproducing head positions, the tape T is clamped by the head surface and the pad 12, and the friction between them eventually becomes a loss in tensile force.

Therefore, in view of the above points, the present applicant has proposed a measuring device 1B as shown in FIG.

The figure is a plan view with the upper half of the apparatus removed to show the internal structure and for explaining the measurement of tape tensile force, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the figure, reference numerals 15 and 16 indicate an outer ring and an inner ring that constitute the meter unit 13. For example, a pin 17 is inserted into the inner ring 16 at a symmetrical position and is prevented from rotating by the upper and lower halves 3 and 4. A large number of steel balls 18 are arranged within the gap, separated from the inner hole.

In other words, the outer ring 15 and the inner ring 16 have a radial ball bearing structure, and the outer ring 15 is rotatable as an outer race.

As mentioned above, this meter unit 13 is spring balanced, and a spiral spring as a means for elastically biasing the outer ring 15 is provided on the back side (described later), and in this example, a clockwise torque is applied to the outer ring 15. When the spiral spring is bent, the spiral spring is bent in proportion to the torque.

In other words, the rotation angle of the outer ring 15 is always proportional to the torque, which is an inherent property of spring balance.

The winding frame 14 will also be described later, but its outline is that the winding ring 20 is attached around the hub 19 via a slip means.
It has a structure with a

In this example, one end of the tape T is locked around a part of the outer ring 15 of the meter unit 13 and wound around it multiple times, and the tape T is pulled out from the right side circumferential surface of the outer ring 15 and the other end is wound around it. It is guided to the circumferential surface of the winding ring 20 of the frame 14 and is locked therein.

That is, the configuration is such that the tape T is stretched along only the right side portion of the tape path preset on the front surface of the cassette case (the tape entry side of the stretched portion is defined as upstream).

Therefore, a guide roller 21 (
or a miniature bearing) is provided to bring the tape T from the outer ring 15 to the above-mentioned partial tape path.

Therefore, there is no tape path tP shown by an imaginary line to the left of the guide roller 21 for convenience, and the guide roller at the left corner position and the pad at the center opening are also removed.

In the figure, 22 is a reel shaft engaging hole formed in the inner ring 16 of the meter unit 13, 23 is a reel shaft retaining hole in the reel hub 19, and 24 is a g unit mark displayed on the outer ring 15 of the meter unit 13. The scale 25 indicates a pointer also provided on the inner ring 16, and 26 indicates a liner laid on the inner surface of the lower half.

The illustrated state is a case where the measuring device 1B is attached to a tape recorder and the tape tensile force is to be measured. The capstan 29 is located in the capstan insertion hole 8b, and
When a predetermined operation is performed, the pinch roller 30 is brought into rolling contact with the capstan 29 via the tape T.

The pinch roller 30 is pressed against the capstan 29 by the elastic biasing force of the pinch lever 31, but the driving torque (pulling force from the tape side) due to the cooperation of the capstan and the pinch roller is basically Since it is determined only by the strength of the spring 35 that applies a biasing force to the lever around the pivot shaft 32 of the pinch lever 31 and the rolling contact position of the pinch roller 30 (left and right positions in the figure), in the case of the exemplary measuring device 1B, the virtual line It can be understood from the above that the illustrated erasing head 34 and recording/reproducing head 35 are irrelevant to the measurement.

However, there are also problems with the measuring device 1B of this example.

That is, since this is a configuration in which the tape T is pulled out from the right side circumferential surface of the meter unit 13, the wrap angle θ at the guide roller 21 becomes large, and due to this, the guide roller 21
This is the point where the rotational friction causes a loss in tape tensile force.

Although this loss is considerably smaller than that in the previous example, it still causes an error in the measured value displayed by the meter unit 13.

In the case of this measuring device 1B, the rotating directions of the movable outer ring 15 of the meter unit 13 and the winding ring 20 of the winding frame 14 are opposite to each other.

The main purpose of the present invention is to further improve the measuring device as shown in FIG.

FIG. 3 is a plan view showing an embodiment of the tape tensile force measuring device IC according to the present invention, and since this is shown in accordance with FIG. Although omitted, the gist of the present invention is to reduce the wrap angle θ of the tape T with respect to the guide roller 21 as shown and explained in the previous example, thereby reducing the loss during measurement that occurs in tape tensile force to a negligible extent. However, as a result, the measured value displayed on the meter unit 13 is made to match the actual tape tensile force.

Specifically, the tape T is wound around the outer ring 15 of the meter unit 13 in the opposite direction to that shown in FIG. ing.

Therefore, as is clear from the diagram, the wrap angle of the tape T with respect to the circumferential surface of the guide roller 21 is smaller than that in the previous example, and the wrap angle of the tape T with respect to the circumferential surface of the guide roller 21 is smaller than that of the previous example, and the wrap angle of the tape T with respect to the circumferential surface of the guide roller 21 is smaller than that of the previous example.
The above-mentioned loss due to rotational friction can be made to a negligible level, and if the guide roller 21 is made of the aforementioned mini-Achia bearing cylinder or the like, the rotational friction will be further reduced.

In the case of the measuring device 1C of the present invention, the movable outer ring 15 of the meter unit 13 and the winding ring 20 of the winding frame 14 rotate in the same direction.

FIG. 4 is a rear view showing the structure of the meter unit 13 and the winding frame 14, and the bottom side of the movable outer ring 15 has a circular recess 1 with a diameter of
5', and a spiral spring 36 made of, for example, a piano wire having a required spring constant is arranged in this recess, the outer end of which is a part of the inner wall of the recess, and the inner end of which is a part of the curved surface of the fixed inner ring 16. They are each locked in place.

If torque is applied to the outer ring 15 in the clockwise direction (counterclockwise in FIG. 3) in the state shown, the outer ring 15 will bend the spiral spring 36 in proportion to the load torque and rotate, so that the rotation angle is always constant. The point that it is proportional to the applied torque is as described above.

Further, the winding frame 14 of this example has a structure in which a slip ring 20 (winding ring) is provided around the hub 19, and the slip means corresponds to the outer periphery of the hub 19 and the inner periphery of the winding ring 20. Circumferential grooves 19' and 20' are formed, and a spring 37 made of piano wire or the like bent into a substantially square shape is bent and inserted into the inner circumferential groove 20' of the winding ring 20. is arranged in an outer circumferential groove 19' of the hub 19 to provide relative retention of the hub 19 and the winding ring 20 and a slipping action therebetween.

The reason for this structure is to maintain the auto-shutoff mechanism of the tape recorder in an inoperative state without stopping the rotation of the take-up reel shaft when measuring tape tension.

However, the structures of the meter unit 13 and the winding frame 14 are described in the above-mentioned prior application.

From the above, the effects of the present invention are already clear,
In short, although the present invention has a simple configuration, it is possible to almost completely match the measured value displayed on the meter unit with the actual tape tensile force, and its practical benefits are significant.

[Brief explanation of the drawing]

Fig. 1 is an external perspective view showing an example of a cassette type tape tensile force measuring device, Fig. 2 is a plan view for explaining the internal structure and tape tension measurement of another example, and Fig. 3 is related to the present invention. FIG. 4 is a plan view showing an example of the measuring device, and a rear view of the meter unit and the winding frame. In the figure, 1C is the entire tape tensile force measuring device, 4 is the lower half, 13 is the meter unit, 14 is the winding frame, 15 is the outer ring, 16 is the inner ring, 19 is the hub, 20 is the winding ring, 21
29 is a guide roller, 29 is a capstan, 30 is a pinch roller 24 is a scale, 25 is a pointer, and T is a tape.

Claims (1)

[Scope of utility model registration request] A spring-balanced meter unit having a movable outer ring and a winding frame are disposed in the cassette case, and the tape locked and wound around the movable outer ring is guided to the winding frame, and the tape between the two is provided with a capstan and a winding frame. In a device that applies cooperative driving torque of a pinch roller and displays the tape tensioning force as the amount of rotational displacement of the movable outer ring, the tape tensioning path is defined by a section near the capstan and the pinch roller upstream and downstream. In addition, a guide roller or the like is provided at an upstream position of the stretching path, and the direction of rotation of the movable outer ring and the winding frame is controlled relative to the circumferential surface of the guide roller, etc. 1. A tape tensile force measuring device characterized in that tapes are brought into contact with each other so that they are in the same direction.