JPS6336059B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Application The invention provides at least one winding core, which consists of two ring parts, namely an inner part with a driving pin and an outer part. At this time, the driving pin fits into the outer bridging piece of the drive mandrel on the device side to drive the rotation of the winding core, and at this time there is only a slight play between the inner surface of the cassette casing and the ring part, and at that time A certain radial play is provided between the inner part and the outer part, and one of the ring parts has at least one driving projection, which drives the other ring part for rotational drive. The present invention relates to magnetic tape cassettes, in particular compact cassettes, which are respectively connected to entrainment recesses in the magnetic tape cassettes.

Prior Art According to French Patent No. 2233675,
Tape cassettes for playing musical instruments are known, and of course nothing is said here about the use of magnetic tape. The known winding core thus consists of a boss that fits onto the drive mandrel and a ring part that winds or creates the tape. Coupling devices are provided between them, which make possible a radial offset between the boss and the ring part and thereby compensate for distance tolerances between the drive axes of the various devices. . In this case, the boss has stationary driver pins on its inner periphery, which engage in recesses in the ring part. The boss and the ring part can also be constructed in one piece from an elastic material, with a deformable arm being formed between the two parts.

According to U.S. Pat. No. 3,512,734, a film cassette is known in which a film core is formed with elastic connecting fingers, with respect to a predetermined form of the drive shaft for the core. Since the winding core is being rotated and is not being rotated in the opposite direction, and the winding core is free, the connecting finger is moved so that the drive shaft rotates with respect to the stopped winding core. arranged and formed. The spring properties of the connecting fingers are only used to enable automatic switching from one operating state to another. Apart from their coupling function to the drive shaft, the coupling fingers have no influence on the torque acting on the winding core.

From DE 20 56 932 A1, a tape cassette is known which has a tape roll on a core which can be rotated on a support device with ball bearings. In order to compensate for tolerances in the position and shape of the drive spindle, the inner part of the winding core is made large relative to the spindle diameter, so that a tilting of the spindle can be tolerated. The cores have narrow tolerances between the cassette walls to prevent contact between the cassette walls and the tape roll surface in conjunction with large tape guide systems. These treatments are not suitable for mass production and are too expensive for compact cassettes.

The alignment of the cassette with respect to the tape recorder or its drive shaft in a compact cassette system is made possible by the play of the core relative to the cassette casing in the radial and axial directions (FIG. 1). According to DIN 45516, the following tolerances are taken into account:

Radial play: min. 1 mm, max. 1.9 mm Axial play: max. 1.3 mm Radial play of the core relative to the cassette casing causes the following drawbacks:

Γ During high-speed winding, the winding core hits the casing or casing collar, especially on the unwinding side, and produces an audible rattling noise.

Γ During the playing operation and when the cassette is vertically supported in a tape recorder, the core rolls intermittently on the protruding casing collar, resulting in rapid tape tension fluctuations and, on the other hand, pitch fluctuations.

Axial play can set the core or tape roll at an angle to the cassette bottom or lid, or wobble, if radial play is present. This may cause the Γ tape to be wound unevenly. The tape roll becomes uneven and the moment of friction can increase significantly. On the contrary, it often sticks to the cassette.

Γ During sudden starting and stopping of the cassette, the tape may fall off the tape roll (bend) and become trapped between the tape roll and the cassette casing.

OBJECTS OF THE INVENTION It is therefore an object of the invention to narrow the tolerances of the winding core in the cassette casing and to improve the contact between the winding core and the drive mandrel, as well as to improve the contact between the winding core and the drive mandrel. The idea is to provide play primarily through the core. Furthermore, when the drive mandrel is inserted into the cassette, a sufficient connection to the core is possible while maintaining the necessary play during cassette movement.

Structure of the invention This problem is solved as follows. That is, the inner parts with the driving projections themselves, or at least one element between the driving projections and the driving recesses, are designed elastically and connect the inner parts for the rotational drive of the winding core. A predetermined play is formed between the parts.

Here, play is understood in the broad sense that relative movement is possible between the inner part and the outer part. It is therefore advantageously possible to achieve optimal alignment of the outer part of the core in the cassette casing and to achieve exactly sufficient axial or radial play between the core and the casing, in which case the tape recorder The play required for alignment of the cassette with respect to the drive shaft of the core is provided by the configuration and arrangement of the inner portion relative to the outer portion of the core.

As is known, it is advantageous if only approximately radial play exists between the inner and outer parts of the winding core, so that tolerances or inaccuracies of the drive mandrel can be compensated for.

If the inner part is made of an elastic material and the outer part is made of an inelastic material, it can be provided that the inner part flexes upon insertion or withdrawal of the drive mandrel. On the contrary, it is only necessary to ensure that the inner part is entrained to the outer part of the core when it is inserted into the cassette, and that it is released there again when the cassette is removed. It can be fixedly provided.

Furthermore, the inner part can be designed as a clamping part for the drive mandrel, which improves the entrainment when the drive mandrel is rotated and prevents the occurrence of undesirable natural movements of the winding core relative to the respective drive mandrel. Can be done.

It is advantageous if the elastic intermediate element consists of a rubber-elastic material, in particular a foam material, or of a flexible film material, which allows for economical production. Finally, a plurality of elastic elements can be arranged symmetrically on the winding core, or one elastic element can be arranged asymmetrically on the winding core, thereby providing centric or eccentric core support on the drive mandrel. be able to.

The inner part can be designed as a clamping part for the drive shaft or for the ring collar in the cassette, as described above, so that a certain correspondence is achieved.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

1A and 1B show a typical winding core 55 utilized in compact cassettes, having an entrained outer bridging piece 71 and in conjunction with an interlocking machine drive mandrel 61. The cassette casing 81 is
It is shown in a diametric section through one inlet opening 91 and around the opening, symmetrically with respect to the horizontal center plane of the casing, a ring collar 110a or 110b in each case projects into the interior space of the casing. . The winding core 55 consists of one piece,
It is generally made of plastic and has fixed drive pins 111 on its inner periphery, which are seated on the outer bridge 71 of the drive axle 61 for rotational drive. The dimensions of the circular undercut 112 determine the radial play rs=rs1+rs2 of the core 55 with respect to the ring collars 110a, 110b. The axial play as consists of the axial partial plays as1 and rs2. Depending on these relative dimensions, the ring portion 11
The axial play of 3 is the opposite ring collar 110
Axial play of core 55 between a and 110b ks
It can be determined by

In this embodiment, the central part 141 of the core 55, which has six pins 111, is connected to the lower ring collar 1.
It is listed on 10b. As a result, the magnitudes of the axial play values as1 and as2 are not the same. In the ideal case, during operation in the device the winding core 55 is held just in the central position of the casing 81, so that as1=as2.

2A and 2B show a first winding core 151, the same parts as in FIG. 1 having the same reference numbers. The core 151 consists of two parts: an inner part 116 and an outer part 117, the shape of the inner part 116 approximately corresponding to the central part 141 of the core 55, and the shape of the outer part 117 approximately This is the same as the ring portion 113. The inner part 116 and the outer part 117 are coupled or connected or capable of being coupled or coupled to each other through suitable measures, so that when the drive axle 61 acts on the inner part 116,
It is adapted to transmit torque to the outer portion 117. As shown in FIG. 2A, the inner part 116 has around its circumference entrainment projections 181, for example three in number, which engage in entrainment recesses 119 on the inner circumference of the outer part 117. The connection between the inner part 116 and the outer part 117 may be realized in any other suitable way. Inner part 1 as shown in Figure 2B
There is a special radial play between 16 and the outer part 117.
rk is provided, while the radial play rs remains the same as in FIG. However, the outer part 117
has a considerably smaller axial play as3 relative to the casing 81, which results in the aforementioned advantages of an improved and more precise winding rotation. Advantageously, a special play rk may account for tolerances or errors on the device side or on the cassette side, such as the tilted position of the drive axle,
Things such as drive mandrel placement errors, drive mandrel diameter variations, etc. can be compensated for. In the axial direction, unless dimensioned as shown in FIG.
The inner part 116 and the outer part 117 are freely movable relative to each other. Inner part 1 relative to outer part 117
The axial movement of 16 is limited in this example to the distance ks between ring collars 110a and 110b.

FIG. 3 shows a winding core 120, the outer part 121 of which has narrower tolerances relative to the ring collars 110a and 110b, and thus in the radial direction, than the outer part 117 of FIG. has. This reduction in radial play further provides the advantage of improved centering and thus precise rotation of the core 120 and therefore of the overlying tape roll (not shown). Inner part 122
corresponds to section 116 in FIG. 2, which has a somewhat reduced diameter. FIG. 4B shows the inner portion 125, the outer and inner diameters of which are variable depending on the respective size of the slits 124. If the material of the inner part 125 itself is not sufficiently flexible, an elastic part 123 with a narrow cross section may be provided diametrically opposite the slit 124. If the dimensions of the entrainment projection 126 are suitable, the inner part 125 can be clamped to the ring collar 110b via the surrounding edge (fourth
(see figure B), the inner part 125 is loosened from the ring collar 110b only when the drive shaft is inserted,
and is moved into a central position and connected to the associated outer part, not shown here. In each case, the entrainment projections 126 are dimensioned relative to the recess in the outer part such that, for the respective diameter of the inner part 125, an unhindered entrainment of the outer part of the core takes place. This inner part 125 of the winding core with a flexible circumference makes it possible to compensate diameter tolerances of the drive mandrel particularly well for an optimally centered drive. A series of measurements on 117 different cassette devices revealed that 7.35mm and 8.0mm
Diameter tolerances between . Further, for example, if the diametrical pins 111a and 111b have a distance corresponding to the minimum diameter of 7.35 mm, and the other pins 111
The lengths of the driving pins may be different if they are adapted to a maximum diameter of 8.0 mm and vice versa. However, it is desirable to configure the two diametrical pins to be of the same length.

FIG. 5 shows an asymmetric core configuration 128, as opposed to the previously described cores which are symmetrical about the center plane of the cassette. The difference lies generally in the outer part 127, which, in contrast to the outer part 121 in FIG. 3, has an undercut 136, which corresponds to 112 in FIG. have The lower half of outer section 127 has a narrow tolerance to ring collar 110b, like outer section 121 in FIG. This core configuration offers the advantage that alignment of the winding core 128 takes place only in one half of the casing, here only on the lower side with the ring collar 110b. This is because otherwise the tolerances of the upper and lower parts of the casing would have to be taken into account when determining the dimensions of the winding core.

FIG. 6A shows the inner part 1 as in FIG. 2A.
22 and an outer part 121, an elastic medium, for example a rubber-elastic foam material, is provided here between the entraining projection 118 and the entraining recess 119. If three identical pieces of foam material 129 are used, the inner part 122
automatically resettable centering.
If only one piece 129 is used, or if pieces with different elastic properties are used, the desired eccentricity of the inner part 122 can also be achieved, so that for example one or two entrainment bridging pieces of the drive axle 61 are used. 71 contacts pin 111. Figure 6B shows the same core 1
30 but with a film piece 131 instead of the foam material piece 129.

In both cases, the inner part 122 and the outer part 121
A resilient connection between the two is desired and the resilient pieces 129 and 131 are selected from suitable materials and suitably dimensioned.

A core 135 is shown in FIG. 7 as another modification. In this case, as is clear from FIG. 7, the inner part is the inner part 12 of FIG. 4 to which the drive shaft 61 is attached.
It is set up in almost the same way as 5. The drive shaft and the inner unit thus fit into the cassette opening 91 as a whole and in the outer part 133 located in the cassette casing 81, which outer part is approximately the same as the outer parts 117 and 121; And if necessary, it can have an elastic foam material 129 or a film piece 131.

The connection between the cassette and the inner unit and the outer part within the cassette can be made in any suitable way, so that the drive torque is reliably transmitted almost without slip to the outer part and thus to the tape roll. be done. For example, conical inner and outer parts are conceivable, which parts may have a suitable material for fastening, but which also makes it possible to easily separate the parts.

By appropriate selection of materials for the inner and outer parts and possibly the intermediate part,
A desired coupling force can be established between the inner part and the outer part during the rotational drive. However, the outer part should be constructed to be sufficiently rigid that it can more or less fully perform the tape roll support function.
Elastic materials can be used for the inner part, as long as the torque of the drive axle is still transmitted to the outer part relatively without loss. By using elastic materials in the inner part or in the middle part, care should be taken not to select too small the tolerances rs and as of the outer part relative to the cassette casing.

The degree of radial and axial play of the outer part with respect to the casing is 0.1 mmrs, as
Values in the range of 0.2 mm are realistically achievable.

With the connection according to the invention between the inner part and the outer part, an elastically movable configuration of the driving pin 111 is not necessary, but if the entire inner part is designed elastically, it is also disadvantageous that the pin is elastic. isn't it.

In reality, the play between the inner and outer parts of the mind is
The same level as play rs (see above).

In practical experiments, the mechanical and electroacoustic properties of commonly available compact cassettes can be significantly improved by equipping them with a core formed according to the present invention. By moving the inner part to the device side, that is, by forming a drive mandrel with a closed inner core inside the cassette, the cassette can be made cheaper and the torque transmission from the drive mandrel to the inner core can be improved. improvement is possible.

The elastic connection between the inner part and the outer part can be made, for example, by means of a rubber-elastic material.

According to the invention, the necessary play is advantageously created between the inner part and the outer part in this embodiment of the invention, so that a close alignment of the outer part with respect to the cassette casing can be achieved without making any changes to the cassette casing. be exposed.

[Brief explanation of drawings]

FIGS. 1A and 1B are views showing a known one-piece winding core with a drive mandrel inserted in a cassette casing, FIG. 1A being a plan view with the cassette lid removed; FIG. The figure is a sectional view taken along the line ab, and Figures 2A and 2B are two views according to the present invention in which the drive shaft is fitted in the cassette casing.
Figure 2A is a plan view with the cassette lid removed, and Figure 2B is a diagram of the divided core.
3 is a view of the core similar to that shown in FIG. 2B but with reduced radial play; FIG. 4A is a cross-sectional view along a line with a slit in the core that is divided into two parts. 4B is a plan view of the inner portion shown in FIG. 4A; FIG. 5 is a diagram of a two-part core having an asymmetric outer portion with respect to a horizontal plane; FIG. 4B is a plan view of the inner portion shown in FIG. 4A; At that time, as mentioned at the beginning, the individual free play values were 1 mmrs 1.9 mm and as 1.3 mm, as shown in Figure 6A and Figure 6.
Figure B is a diagram of a two-part winding core having a flexible intermediate piece between the inner part and the outer part, and FIG. 7 is a diagram of a two-part winding core in which the drive mandrel and the inner part are integrated. 55, 130, 135... Winding core, 61, 71... Drive shaft, 110a, 110b... Ring collar, 1
11... Taking pin, 116, 122, 125, 13
2... Inner part, 117... Outer part, 118... Entrainment projection, 119... Entrainment notch, 129, 131... Intermediate element.

Claims (1)

Claims: 1 At least one winding core 55 is provided, which winding core consists of two ring parts, namely an inner part 116 with a driving pin 111 and an outer part 117, with the driving pin 111 The pin 111 engages in the outer bridging piece of the machine-side drive mandrel 71 for the rotational drive of the winding core 55, with only a slight play existing between the inner surface of the cassette casing and the ring part, with the inner part A certain radial play is provided between 116 and the outer part 117, and one ring part is provided with at least one driving projection 1.
18, which entraining projections are each connected to a entraining recess 119 in the other ring part for rotational drive, the inner parts 116, 12 having entraining projections 118;
2, 125 and 132 themselves, or at least one element 129, 131 between the entraining projection 118 and the entraining recess 119, are designed elastically and for the rotational drive of the winding cores 55, 130, 135. A magnetic tape cassette characterized in that inner parts 116, 122, 125, 132 are connected and a predetermined play rk is formed between these parts. 2. A cassette according to claim 1, wherein the elastic intermediate element 129 consists of a rubber-elastic material, in particular a foam material. 3. A cassette according to claim 1, wherein the elastic intermediate element 131 consists of a flexible film material. 4 The elastic intermediate elements 129 and 131 are connected to the winding core 13
4. A cassette according to claim 2, wherein the cassette is arranged symmetrically at 0.135. 5. Claim 2, wherein the elastic intermediate elements 129, 131 are arranged asymmetrically at the winding core.
Or the cassette described in item 3. 6 The inner part 125 is formed as a clamping part for the drive axle 61.
The cassette described in section. 7 The inner part 125 has a ring collar (110b,
4. A cassette according to claim 1, wherein the cassette is configured as a clamping part for the purpose of FIG. 4B.