JPH04268274A - Tape cassette, especially magnetic tape cassette - Google Patents

Abstract

PURPOSE: To exactly guide a tape by correcting the distortion of a plastic casing by plastically forming one of plural adjacent guiding elements on a bottom face part and the other guiding element on an apex face part. CONSTITUTION: Concerning this tape cassette, guiding elements 24, 15, 16 and 17 are provided respectively symmetrically to a lateral center line (q), one-side elements 15 and 17 of pairs (24-15, 15-16 and 16-17) are formed on the bottom face part and the other-side elements 24 and 16 are formed on the apex face part respectively. Then, a tape 3 is passed from a hub 1 through a guiding pin 22 and a deflecting roller 14, passed through guiding webs 24 and 15 formed as flat webs, pinch roller 13, guiding web 16 and guiding pin 17 to the center line (q) and further traveled to the hub 2 in reverse order.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD The present invention relates to a housing having a bottom part and a top part (4, 5) and a lateral centerline (q), and a turning element (
14) a tape cassette that is guided within the casing by guide elements (16, 17) molded on the bottom surface (4) and the top surface (5), respectively;
It particularly concerns magnetic tape cassettes.

[0002] The casing bulge of the compact cassette is provided with three openings for receiving magnetic heads. Similarly, the housing ridge is provided with guiding elements for the magnetic tape, and the recording/playback quality of the cassette varies considerably depending on these guiding elements. It has traditionally been done to form the upper and lower halves of the housing using relatively inexpensive plastics, especially under heat, but this results in a change in the position of the guiding elements and, as a result, an impact on the quality of the housing. becomes worse.

0003

2. Description of the Related Art Tape guide elements are provided on the right and left sides of the top surface of the housing with respect to the lateral center line, or pairs of inner guide pins are provided on the bottom surface symmetrically with respect to the lateral center line. Compact cassettes are known in which pairs of adjacent outer guide pins are each molded onto the top surface. however,
This either results in an asymmetrical arrangement of the guide elements or only corrects symmetry errors of the guide elements in the vicinity of the lateral center line.

[0004] US Pat. No. 3,661,345 discloses that a deflection pin having a slightly conical cross section that engages with each other from the bottom and top surfaces is attached together, and is made compact by forming an outer cylindrical shape, for example. Discloses forming a fixed deflection pin in a cassette. However, this can lead to significant deterioration under frictional conditions, and the simultaneous mounting of the cone can lead to even greater distortions in the position of the guide element than the existing distortions are corrected.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve tape cassettes in terms of tape guiding accuracy.

[0006]

SUMMARY OF THE INVENTION However, the above object is to provide a housing having a bottom part and a top part (4, 5) and a lateral centerline (q), a turning element (14), a bottom part (4) and a top part. (
5) respectively molded guide elements (16, 17)
A tape cassette, in particular a magnetic tape cassette, consisting of a tape guided in a case by a
Adjacent guide element pairs (24
, 15 and 15, 16 and 16, 17) are provided symmetrically, one guide element (15 and 17) of each pair on the bottom part (4) and the other guide element (24 and 16) of the same pair. It has been found by the inventors that this can be achieved by means of a tape cassette characterized in that each of the following is molded onto the top surface (5).

[0007] This makes it possible, for example, to compensate for thermally induced tilting of the guide element and thus to prevent its angular errors caused by the cassette.

Furthermore, in other embodiments, ie cassettes in which the deflection elements and the guide elements are arranged symmetrically, a pair of adjacent guide elements is arranged between each deflection element and the lateral centerline. It is preferable to be there.

This provides an evenly compensated tape guiding effect on each side of the cassette on either side of the lateral centerline, especially on both sides (after rewinding) as in the case of compact cassettes. This is particularly advantageous in cassettes operated in

[0010] In a preferred embodiment, at least one pair of adjacent guide elements are arranged in close proximity to the deflection element.

As a result, errors in the position of the deflection roller axis as well as the guide pin in its vicinity can be advantageously corrected.

Furthermore, at least one pair of adjacent guide elements include:
It is particularly preferred to have guide elements arranged close to each other, each with a tape adhesive surface.

[0013] The partial guide elements arranged in close proximity in this way form a single guide element which automatically corrects when the two partial guide elements are tilted in opposite directions and the tape contacts both contact surfaces centrally. It has the effect of

[0014] Furthermore, it is preferred that the longitudinal axes of a pair of adjacent guide elements are substantially parallel to each other. A further geometric feature of the guide element according to the invention is that it is in the form of an elongated web or a cylindrical guide pin or a combination of both.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments of the invention will now be described with reference to the accompanying drawings.

The known standard compact cassette K is
two hubs 1 rotatably mounted in a common plane;
2, and the tape 3 is wound onto and unwound from these. This cassette has a bottom part and a top part 4,
5, and each side has a front wall, a back wall, and side walls 6, 7.
and 8. The housing halves each have a housing ridge 10a, 10b, each extending from the front wall 6 towards the rear wall and adapted to accommodate at least one recording/reproducing magnetic head 11. (Figure 2
reference). The front wall 6 has two openings for accommodating further elements, such as an erasing head 12, a rubber pinch roller 13 for driving the tape by a capstan 19, etc. In order for each of these elements to be able to bring about the necessary precisely defined contact with the magnetic tape 3, the tape 3 must be moved from the tape roll of the hub 1 along the front wall 6 to the hub 2.
The deflection roller 14, the guide element 15,
16 to form the tape loop 3 or in the reverse order if the cassette is to be operated in the opposite direction. If these guiding elements deviate even slightly from their vertical position by more than 25 μm, this leads to a decisive azimuthal error, which has a decisive negative effect on the high-frequency audio signal. Make the cassette case as strong as possible,
In order to provide longitudinal stability in this part, ribs or webs 25 extend preferably from the side walls around the deflection roller 14. The thin walled steps 18a, 18b introduced into the housing ridges create an asymmetry in the housing that cannot be corrected by common design measures. a bottom part that covers the tape roll, a surface part 4;
5 is generally about 1.8 mm, but the wall thickness of the housing protrusions 10a and 10b is about 1.0 mm at least in the opening area in the front wall 6 (hereinafter referred to as the front opening). It's getting thinner. In the case of injection molding, the above-mentioned asymmetry results in distortions in the material, which, for example in the case of exposure to heat, are mutually balanced by bending of the ridges 10a, 10b in directions A and A' (FIG. 1).

FIG. 2 shows a housing K constructed symmetrically with respect to the transverse center line q as an embodiment of the invention.

From the hub 1, the tape 3 passes through the guide pin 22, the deflection roller 14 of the spindle 23, then through the guide elements 15, 24, which are formed as flat webs, then between the pinch roller 13 and the capstan 19, and then through the deflection roller 14 of the spindle 23. Via the guide web 16 and the guide pin 17 the transverse center line q is reached and the guide and deflection elements in the other half of the cassette are now run in the reverse order to the hub 2.

For the purposes of the invention, adjacent tape guiding elements are defined as guiding webs 15, 24 arranged in close proximity.
, a guide web 16, and a guide pin 17, which are arranged at relatively intervals. That is, on each side there are two pairs of close guide elements (15, 24 and 16, 17) between each deflection roller 14 and the lateral centerline q. The number of element pairs can also be increased as will be explained later.

Guide elements 15 and 17 provided on the bottom part 4
is shown as a top view, the guide elements 24, 16 provided on the top surface 5 are shown with diagonal lines to distinguish them.

[0021] The guide webs 15, 24 are arranged in close proximity to each other in an uncomplicated assembly and are configured in cross-section as a more or less elongated rectangle, with their feed contact surfaces being slightly rounded. . The thickness of the webs 15, 16, 24 is determined by possible manufacturing and assembly tolerances.

The second pair of guide elements 16, 17 are arranged at a certain distance from each other, but this mounting arrangement on the top part 5 and the bottom part 4 is similar to that of the first pair 15, 24. It shows the same correction effect as in the case.

The manner in which the adjacent guide elements are mounted, one on the bottom side and the other on the top side, can be achieved, for example, in the direction A of the thermally induced housing ridge 10A and in the direction A' of the ridge 10B. The deflection has the result that the guide elements are deflected to the same extent in opposite directions relative to the tape 3 (provided that the bottom part and the top part are made of the same material). This deflection in the directions of arrows A and A' has the following effect on the running tape.

That is, in the transverse center line q, the tape 3 is likewise deflected in the direction A at each first guide element 17, which is integrally molded on the bottom wall 4, more precisely on the protuberance 10a. I am forced to do it. However, the second guide element 16, 24 then molded onto the ridge 10b
A deflection in the opposite direction (direction A') is immediately followed. As a result, the tape 3 is attached to each adjacent pair of guiding elements (1
Take an intermediate position at 7, 16) and (15, 24),
This intermediate position is maintained by using pairs of guide elements arranged symmetrically along the housing front face 6.

Of course, the guide elements 16, 17, 22
The use of said guiding elements such as 15, 24, doubled by correspondingly molded fittings 16A, 17A, 22A on the bottom and top sides of the housing, allows automatic correction of each pair of guiding elements. It is also possible to ensure that This modified embodiment is shown schematically in FIG.

The configuration of the tape cassette according to the present invention makes it possible to bring about numerically significant improvements as shown below compared to conventional compact cassettes. A compact cassette marketed by the applicant company was tested against a compact cassette (CC) according to the invention and the following results were obtained. Both compact cassettes were heat aged (HA) at 85°C for 8 hours.
The azimuth angle of the magnetic head gap of the tape of each cassette was measured before and after. The numbers are shown in the table below.

[0027]
Table CC type HA anterior angle (minutes) HA posterior angle Commercially available CC
<3.5'
<5' CC of the present invention <1.9'
<2.8' One angle is 1/60 of 1 degree.

With the present invention, therefore, the improvement in azimuth angle can be made by a factor of less than 2, ie the azimuth angle error in the cassette can be made by at least a factor of 2 or less.

There are no known commercially available compact cassettes that provide such improved azimuthal angles and achieve tape guiding accuracy at relatively low expense.

For the purposes of the present invention, the magnetic tape cassette is applicable to any audio, video, data and metrology tape cassette.

[Brief explanation of the drawing]

[Fig. 1] Cross-sectional view of a conventionally known compact cassette.

FIG. 2: Schematic plan view of a compact cassette with tape guiding and redirecting element according to the invention;

FIG. 3 is an enlarged partial plan view of a compact cassette according to the invention with different tape guiding elements;

[Explanation of symbols]

K...compact cassette q...Case body lateral center line 1...Hub 2...Hub 3...Magnetic tape 4...Bottom part, top part 5...Bottom part, top part 6...Front wall, back wall, side wall 7...Front wall, back wall, side wall 8...Front wall, back wall, side wall 10a... Enclosure raised part 10b... Enclosure protrusion 11...Magnetic head 12...Erasing head 13...Pinch roller 14...Direction changing roller 15...Guide element (guide web) 16...Guide element (guide web) 17...Guide element (guide web) 18a... Raised step part 18b... Raised part step part 19...capstan 22...Guide pin 23...Spindle 24...Guide element (guide web)

Claims (8)

[Claims] 1. A housing having a bottom part and a top part (4, 5) and a lateral centerline (q), and a turning element (14).
), a tape guided in the housing by guiding elements (16, 17) molded on the bottom (4) and top (5) respectively, and in particular a magnetic tape cassette, comprising: Above horizontal center line (q
) with respect to adjacent guide element pairs (24, 15 and 15, 1
6 and 16, 17) are provided symmetrically, one guide element (15 and 17) of each pair on the bottom part (4) and the other guide element (24 and 16) of the same pair on the top part (4). 5
) A tape cassette characterized in that each tape cassette is molded on the top. 2. A tape cassette according to claim 1, in which adjacent pairs of guiding elements (24, 15 and 15, 16 and 16, 17) are arranged such that each deflecting element (14) and a lateral centerline (
q) A tape cassette characterized in that the tape cassette is disposed between. 3. A tape cassette according to claim 1 or 2, characterized in that adjacent guiding elements (15, 24 and 22,
A tape cassette characterized in that at least one pair of 22A) is arranged in the vicinity of the deflection element (14). 4. A tape cassette according to claim 1, wherein at least one pair of adjacent guiding elements (15, 24 and 22, 22A) has guiding elements arranged close to each other. A tape cassette, each having a contact surface for the tape (3). 5. A tape cassette according to claim 1, comprising a pair of adjacent guiding elements (15, 24).
and 22, 22A), the longitudinal axes of which are substantially parallel to each other. 6. A tape cassette according to any one of claims 1 to 5, comprising guide elements (15, 24 and 16).
A tape cassette, characterized in that the tape (16) is formed to form an elongated web in cross section, and the contact surface for the tape (3) is provided on the narrow side of the web. 7. A tape cassette according to any one of claims 1 to 5, in which the guiding elements (22, 22A and 1
7, 17A) is formed as a cylindrical guide pin. 8. Tape cassette according to claim 6 or 7, in which the guiding elements are connected to the webs (15, 24 and 1).
6A, 16) and pins (22, 22A and 17, 17A
) A tape cassette characterized by having both.