GB2228818A

GB2228818A - A Disc cassette assembly

Info

Publication number: GB2228818A
Application number: GB8904507A
Authority: GB
Inventors: Philip Yung Tak Lam
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-02-28
Filing date: 1989-02-28
Publication date: 1990-09-05
Also published as: GB8904507D0

Abstract

A disc cassette assembly comprising an outer housing 3 and an inner housing 2 in which a recording disc is rotatably mounted, each housing including a central first aperture for access to the disc of a drive means and a second aperture (29a) 29b (31a) 31b (eg Fig 1) for access to a surface of the disc of a write or read head of a record and/or play back apparatus. The inner housing is rotatable about an axis coincident with the axis of rotation of he disc, between a first limit position and a second limit position, so that rotation of the inner housing into its second limit position occurs against the bias of a resilient means to bring the respective second apertures into line. The inner housing is rotated automatically to 'open' the second apertures upon insertion of the cassette assembly into the record and/or playback apparatus, and removal of the cassette assembly from the apparatus causes rotation of the inner housing to its first limit position, under the force of the resilient means, to 'close' the second apertures. Rotation of the inner housing may also operate a shutter (4a) (4b) 5a, 5b to 'open' and 'close' the first apertures in the housings. The cassette comprises seal strip 16 (also Figs. 1, 10, 12, 18 for example), seal strip clip (21) being pushed by member 42 upon cassette insertion to disengage clip 22 and seal strip 16 moved to cause inner housing 2 to rotate via spurs 13 and the shutter to open. The disc hub has conductive plate 9 and connecting rails 10a, b whereby the drive unit can identify the correct drive shaft position. Springs (11a) 11b (Fig 6) stabilise the record disc. Liner membrane (12) is provided and read/write ID button (36) is detailed (Figs 13-17). <IMAGE>

Description

A DISC CASSETTE ASSEMBLY This invention relates to a disc cassette assembly and particularly, but not exclusively, concerns such an assembly capable of use with a computer or a video/audio recording and/or playback unit.

It is well known for video and/or audio cassette assemblies to contain a magnetic material coated plastic tape as the recording material, however, these assemblies are not very satisfactory due to the ease with which a tape of such material can be damaged, broken, stretched or distorted due to the ingress of dirt and dust. Furthermore, such tapes are usually housed in a container which has many openings for the insertion of the tape drive shaft of a drive unit and insertion of the write/read. heads of the drive unit, these openings providing access to the tape of dust and dirt.

In a previous patent application, GB 8827233.2, there is described an improved cassette assembly comprising a rotatable recording disc which is housed in a container having a minimum number of openings for affording access to the disc of the drive means and write/read heads.

However, despite there being fewer openings in the disc container, the disc is still exposed at these openings immediately prior to insertion of the cassette assembly into a drive unit.

There is accordingly a need for a generally improved cassette assembly which should provide means of more reliably preventing ingress of detrimental dust or dirt, preferably by allowing access to the necessary openings in the container only when the cassette assembly is correctly inserted into a drive unit, and such that the openings are closed as the cassette assembly is removed from the drive unit.

According to the present invention there is provided a disc cassette for the recordal and/or playback of information on a recording disc rotatably mounted in the cassette, wherein the cassette comprises an outer housing having a first aperture therein providing access for a drive means to rotatably drive the recording disc rotatably mounted in the cassette when the cassette is inserted into a recording and/or playback apparatus, and a second aperture providing access for a read and/or recording head to read or record as the case may be, information stored or to be stored on the disc, an inner housing mounted in the outer housing for limited rotation therein between first and second limit positions in the plane of the recording disc and about an axis coincident with the axis of rotation of the disc, and having the recording disc rotatably mounted therein for rotation about said axis, said inner housing having a first aperture in the outer housing and alignable therewith when the inner housing is in the second of its limit positions, thereby to provide access to the disc for said read and/or record head, means being provided normally to bias the inner housing into the other, first of said limit positions thereby to prevent access to the surface of the disc when the cassette is removed from the recording and/or playback apparatus, and means being provided automatically to rotate the inner housing relative to the outer housing into the second of its limit positions against the biassing means, thereby to bring said second apertures into alignment upon insertion of the cassette into the recording and/or playback apparatus.

Therefore, the basis of-the present invention is an automatic means for opening the second apertures in the inner and outer housings when the cassette is inserted into a record and/or playback apparatus which comprises rotation of the inner housing from a first position to a second position against the bias of a resilient means, so that removal of the cassette from the apparatus allows the inner housing to rotate back to the first position under the force of the resilient means.

Preferably, the cassette also includes an internal shutter or shutters which are movably mounted therein and movably between a first limit position in which the pair of aligned first apertures in the housings are closed by the shutter(s), and a second limit position in which the pair of aligned first apertures are open to permit access to the centre of the disc drive means of the record and/or playback apparatus.

Furthermore, the shutter(s) are preferably provided with a means to bias the shutter(s) into the first limit position when the cassette is removed from the record and/or playback apparatus, and an automatic means to move the shutter(s) against the shutter biassing means into the second limit position to open the aligned pair of first apertures in the housings upon insertion of the cassette into the record and/or playback apparatus.

Conveniently, the shutter(s) are located between the inner and outer housings in a parallel plane to the recording disc, and movement of the shutter(s), to open or close the first apertures in the housings, occurs within that plane. More favourably, one pair of shutters is located above the inner housing and one pair below the inner housing such that the individual shutters of each pair, when in their first limit position, cooperate to close the first apertures in the inner and outer housings both above and below the disc.

Advantageously, the shutters are engaged with or engageable with the inner housing so that automatic rotation of the inner housing from its first limit position to its second limit position, when the cassette is loaded into a record and/or playback apparatus, also moves the shutters from their first limit position to their second limit position, thus all apertures in the cassette are opened.

The automatic means for rotating the inner housing preferably comprises a drive rod member of the record and/or playback apparatus which pushes the inner housing from its first limit position to its second limit position. Access is provided to the inner housing by the drive rod member by a cut out portion in the outer housing.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made to a preferred embodiment of the present invention, by way of example, to the accompanying drawings, in which; FIGURE 1 is a plan view from above of a cassette assembly according to the preferred embodiment of the present invention, showing the first and second apertures in a "closed" position.

FIGURE 2 is a plan view from below of a cassette assembly according to the preferred embodiment of the present invention, showing the first and second apertures in an "open" position.

FIGURE 3 is a side view "A" of the assembly according to Figure 1.

FIGURE 4 is a side view "B" of the assembly according to Figure 2.

FIGURE 5 is a sectional view of the assembly taken on the line C C of Figure 1 with the apertures in a "closed" position.

FIGURE 6 is a sectional view of the assembly taken on the line D D of Figure 2 with the apertures in a "open" position.

FIGURE 7 is a sectional view of the assembly taken on the line E E of Figure 2 with the apertures in an "open" position.

FIGURE 8 is a part cross-section view of the assembly taken on the line F-F of Figure 2, with the apertures in an "open" position.

FIGURE 9 is a part cross-sectional view of the assembly taken on the line G-G of Figure 1, with the apertures in a "closed" position.

FIGURE 10 is a part cross-sectional view of the assembly taken on the line H-H of Figure 1, with the apertures in a "closed" position.

FIGURE 11 is a part cross-sectional view of the assembly taken on the line I-I of Figure 1, with the apertures in a "closed" position.

FIGURE 12 is a part cross-sectional view of the assembly taken on the line J-J of Figure 3, with the apertures in a "closed" position.

FIGURE 13 is a side view "K" of the assembly according to Figure 1 with the read/write protect slot closed.

FIGURE 14 is a side view "L" of the assembly according to Figure 2 with the read/write protect slot open.

FIGURE 15 is a part cross-sectional view of the assembly taken on the line M-M of Figure 2, with the read/write protect slot open.

FIGURE 16 is a side view of a part of the assembly according to Figure 13, with the read/write protect slot closed.

FIGURE 17 is a side view of a part of the assembly according to Figure 14 with the read/write protect slot open.

FIGURE 18 is a plan view of the seal strip laid flat.

A cassette assembly according to the preferred embodiment of the present invention as shown in the accompanying drawings basically includes a rotatable recording disc 1 for recording and/or playback of visual and/or audio information, an inner housing 2 comprising an upper part 2a and a lower part 2b in which said disc 1 is rotatably housed, an outer housing 3 comprising an upper part 3a and lower part 3b in which said inner housing is rotatably housed such that rotation of the inner housing brings a second aperture 29a, 29b therein into line with a second aperture 31a, 31b in the outer housing to afford access to a surface of the disc 1 of a read/write head of a record and/or playback apparatus.

The rotatable recording disc 1 (shown in Figures 1, 2, 5, 6 and 8) includes a central hub 6 which comprises an upper part 6a and lower part 6b which engage together gripping the recording disc 1 therebetween. At the centre of the hub 6a, 6b there is a central disc hole 7 in which the drive shaft (not shown) of a record and/or playback assembly can locate to turn the hub 6 and thus rotate the disc 1. Around the centre disc hole 7 there are hub pins which extend through each hub part 6a, 6b and the rotatable disc to join them together. The hub pins are stamped at either end to prevent them passing through the hub parts. At least one side of the hub 6 is provided with a hub electronic conductive plate 9 and connecting rails 10a, 10b, so that the drive unit can identify when the drive shaft is in the correct position in the central disc hole 7.

The means for locating and stabilizing the disc 1 in the inner housing 2 comprises a pair of spring fingers 11a and 11b (shown in Figure 6) which comprise a lifter to steady the disc 1 when it is rotating. Between the disc 1 and the inner housing 2 there is a liner membrane 12 to further project the disc 1.

The disc 1 is rotatably housed within the inner housing 2a, 2b (shown in Figures 1 and 2) each part of which comprises a substantially circular surface and a peripheral rim extending substantially perpendicular to the circular surface. The two rims may be interlocked in a clip-like manner so as to seal the two parts to each other to prevent the ingress of dust and dirt. Alternatively, and more preferably the two parts 2a, 2b of the inner housing may be welded together or stuck together using an adhesive.

On the peripheral rim of the inner housing 2, there is at least one spur member 13 (four are shown on Figures 1 and 2). Each of these spurs 13 are made up of two individual spur members one on the upper edge of the rim and one on the lower edge. The spurs 13 are attached to one end of a spurs spring member 14, 15 the other end of which is attached to a member which extends between the upper and lower inner surfaces of the outer housing, (as shown in Figures 9 and 10).

Around the circumference of the inner housing rim there is a seal strip 16 (as shown in Figure 18) with cut out portions along its length.

When the seal strip is in its correct position around the inner housing 2, the spur members 13 engage with the cut out portions 17. Along the upper and lower edges of the seal strip there are cut out portions 18 for engagement with the shutters 4a, 4b and 5a, 5b which are provided to close the first central apertures 30a, 30b and 32a, 32b in the inner and outer housings respectively. At one end of the seal strip there is a hole 19, through which the other end of the seal strip 20 can irreversibly pass to secure the two ends of the seal strip so that the inner housing is tightly secured within the ring formed by the seal strip. The tail end 20 of the seal strip 16 has a clip 21 for engaging with a clip member 22 on the outer housing as will be described below. The seal strip is shown located on the inner housing in Figures 1, 2, 10 and 12.

On the upper and lower outer surfaces of the inner housing 2 there are arcuate rails 23, which engage the inner housing 2 with locating pins 24 which extend from the inner surface of the outer housing. These pins 24 extend from the outer housing, through the respective shutter 4a, 4b, Sa and 5b to engage with the respective arcuate rail 23 on the outer surface of the inner housing. In this way the locating pins 24 support the inner housing 2 and the upper and lower shutters, 4a, 4b and 5a, 5b respectively between the upper part of the inner housing 2a and the upper part of the outer housing 3a, and between the lower part of the inner housing 2b and the lower part of the outer housing 3b respectively. For a better illustration of the locating pins, reference is made to Figures 1, 2 and 7.

These pins allow rotation of the inner housing from a first limit position (shown in Figure 1) to a second upper and lower limit position (shown in Figure 2). The inner housing is prevented from lateral displacement by locating pins 43, which extend between the upper and lower inner surfaces of the outer housing 3a, 3b around the peripheral rim of the inner housing.

The upper and lower shutters 4a, 4b and 5a, 5b respectively are located within the space 25 between the inner housing 2 and the outer housing 3. The upper shutters 4a, 4b are pivotally connected at one end thereof 26 to the outer housing 3a, and the lower shutters 5a, 5b are pivotally connected at one end thereof 26 to the outer housing 3b, so that all shutters are movable about their respective pivots. Each pivoted end 26 of the shutters 4a, 4b, 5a, Sb is connected to a spring member 27 which extends at its other end is connected to a pin member 28 which extends between the upper and lower parts of the outer housing 3a, 3b. Also at the pivoted end of the shutters the shutters 4a, 4b, 5a, 5b engage with the cut out portions 18 in the seal strip 16 which is located around the inner housing 2.

On each substantially circular surface of the upper and lower parts 2a, 2b of the inner housing, there is provided a second aperture 29a and 29b respectively for affording access to a surface of the disc 1 of a write/read head of a drive unit. Furthermore, on each substantially circular surface of the upper and lower parts 2a, 2b of the housing, there is provided a central first aperture 30a and 30b respectively for affording access to the disc hub 6 of a drive shaft of a drive unit. In a similar manner, the upper and lower parts 3a, 3b of the outer housing are provided with a second aperture 31a and 31b respectively, and a first aperture 32a and 32b respectively.

When the cassette assembly is in a closed position as shown in Figure 1, the shutters close the aligned first central apertures in the inner and outer housings to prevent dust or dirt particles from falling onto the hub 6 or the disc 1. The second apertures 29a, 31a of the upper parts of the inner and outer housings, and the second apertures 29b, 31b of lower parts of the inner and outer housings are not aligned when the cassette assembly is "closed".

The outer housing 3a, 3b has a number of cut out portions in its outer surface for the correct location of the disc and drive type identification. Hole 33 in the outer surface of the outer housing engages with a member (not shown) in the drive unit to ensure that the cassette assembly is correctly loaded. A cut out 34 on one edge of the outer housing engages with a member (not shown) in the drive unit to identify the type of drive.

A cut out 35 in the outer housing locates a read/write identification button 36 (shown in more detail in Figures 13-17). This button comprises two parts 36a and 36b and is located in a slot 37 which may be opened or closed by a sliding mechanism. This mechanism comprises a slide rail guide 38 and a cut out valley 39 in the button 36b.

When the button 36a is pushed in, the cut out valley 39 engages with the slide rail guide 38 and slides the button 36a and 36b across.

In this same movement, a side opening 40 in the button 36b is aligned with the cut out portion 35 in the outer housing to open the cut out 35. The open and close function of the side opening 35 is for read/write identification of the assembly by the drive unit. That is to say, the disc cannot by accidentally recorded over when the cut out 35 is in the read only position.

Also, in the outer edge of the outer housing there is another cut out portion 41 which houses the clip member 22 which engage with the tail end clip of the seal strip 21, as shown in Figures 1 to 4. When the assembly is in a closed position as shown in Figures 1 and 3, the tail end of the seal strip 20 covers the cut out portion 41 and thus prevents the ingress of dirt and dust into the outer housing. The tail end of the seal strip 20 is maintained in this closed position by means of the clip 21 which engages with the clip member 22.

When the assembled cassette is inserted into a suitable record and/or playback apparatus, a member of the apparatus 42 moves to disengage the seal strip clip 21 from the clip member 22 and pushes against the tail end of the seal strip 20 in the direction X. The force pushing the seal strip tail 20 causes the whole seal strip 16 to move and, due to the engagement of the seal strip with the spurs 13 of the inner housing 2, this causes the inner housing 2 to rotate about its central axis against the bias of the spur springs 14, from its first limit position to its second limit position. The rotation of the inner housing 2 brings the second apertures 29a and 29b in the inner housing into line with the second apertures 31a and 31b respectively in the outer housing, thus affording access to a surface of the disc 1 of a write/read head of the drive unit.In the same turn of the inner housing 2 and the seal strip 16, the shutters 4a, 4b and 5a, 5b, which are engaged with the seal strip at the cut outs 18 are also moved about their respective pivots 26 against the bias of the shutter springs 27. The movement of the shutters 4a, 4b, 5a, 5b uncovers the aligned central, first aperture 30a, 30b and 32a, 32b in the inner and outer housings respectively, affording access to the disc hub 6 of a drive shaft of the drive unit to rotate the disc.

When the cassette assembly is correctly inserted into the drive unit with the selected correct drive type and the correct positicn of the read/write protect button, then the drive shaft moves into the central disc hole 7 where it is contacted with the hub electronic conductive plate 9 and the connecting rails 10a and 10b which electronically signal that the drive shaft is correctly positioned.

The disc drive head of the drive shaft turns the hub 6 and thus rotates the disc for reading or writing of the data on the disc. The read/write head of the drive unit extends through the second apertures 29a and 31a or 29b and 31b in the inner and outer housings, depending on the side of the disc to be read or written.

When the cassette assembly is removed from the drive unit the drive rod member 42 releases the seal strip tail 21 and the bias of the spur springs 14 forces the inner housing to rotate back from its second limit position to its first limit position so that the second apertures in the inner and outer housings are no longer in line. In this same movement, the bias of the shutter springs 27 force the shutters 4a, 4b and 5a, 5b to turn back about the respective pivots 26 to close the first central apertures 30a, 30b and 32a, 32b in the inner and outer housings.

Therefore, when the assembled cassette is not in use, all side holes and apertures are closed automatically and the disc is completely protected against dirt or dust which could cause damage to the recording media.

The mechanism for rotating the inner housing, as described above is nDt the only way, and the mechanism according to the present invention might comprise a direct means wherein a member of the drive unit directly pushes the inner housing against the bias of the resilient means to uncover the apertures in the container when the cassette assembly is correctly inserted into a drive unit.

Claims

1. A disc cassette for the recordal and/or playback of information on a recording disc rotatably mounted in the cassette, wherein the cassette comprises an outer housing having a first aperture therein providing access for a drive means to rotatably drive a recording disc rotatably mounted in the cassette when the cassette is inserted into a recording and/or playback apparatus, and a second aperture providing access for a read and/or recording head to read or record, as the case maybe, information stored or to be stored on the disc, an inner housing mounted in the outer housing for limited rotation therein between first and second limit positions in the plane of the recording disc and about an axis coincident with the axis of rotation of the disc, and having the recording disc rotatably mounted therein for rotation about said axis, said inner housing having a first aperture therein aligned with the first aperture in the outer housing and providing access to the disc for said drive means, said first apertures being aligned with the axis of rotation of the disc, said inner housing having a second opening located therein at the same radius from the axis of rotation of the disc as the second aperture of the outer housing and alignable therewith, when said inner housing is in the second of its limit positions, thereby to provide access to the disc for said read and/or recording head, means being provided normally to bias the inner housing into the other, first limit position thereby to prevent access to the surface of the disc when the cassette is removed from the recording and/or playback apparatus, and means being provided automatically to rotate the inner housing relative to the outer housing into the second of its limit positions against the biassing means, thereby to bring said second apertures into alignment upon insertion of the cassette into the recording and/or playback appartus.

2. A cassette according to claim 1, additionally including an internal shutter or shutters movably mounted therein and movable between a first limit position in which the pair of aligned first apertures are closed by the shutter or shutters and a second limit position in which the pair of aligned first apertures are open to permit access of the drive means to the centre of the disc, means being provided normally to bias the shutter or shutters into said first limit position when the cassette is removed from the recording and/or playback apparatus, and means being provided automatically to move the shutter biassing means into the second limit position, thereby to open the aligned pair of first apertures upon insertion of the cassette into the playback and/or recording apparatus.

3. A cassette according to claim 2, wherein the shutter or shutters are located and movable within a parallel plane to the recording disc, between the inner housing and the outer housing.

4. A cassette according to claim 2 and 3, wherein one pair of shutters is located above the inner housing and one pair of shutters is located below the inner housing, wherein each pair of shutters comprises a first and second shutter movably mounted within the cassette, and movable between a respective first limit position in which the first and second shutters of each pair cooperate to close the aligned first apertures in the inner and outer housings, both above and below the disc, and a respective second limit position in which the aligned first apertures are open to permit access of the drive means to the centre of the disc.

5. A cassette according to claim 2, 3 or 4, wherein each shutter includes a bias means comprising a shutter spring for biassing the shutter into its first limit position.

6. A cassette according to claim 5, wherein each shutter spring is attached at one end to its respective shutter and at the other end to the outer housing.

7. A cassette according to claim 6, wherein the shutter spring is attached at one end to the outer housing by a spur extending from the inner surface of the outer housing.

8. A cassette according to any one of claims 2 to 7, wherein each shutter is movably mounted in the cassette by means of a respective pivot connected to the inner surface of the outer housing.

9. A cassette according to any one of claims 2 to 8, wherein the automatic means for moving the shutters about their respective pivots from the first limit position to the second limit position against the bias of the respective bias means, comprises rotating the inner housing in the plane of the disc and about an axis coincident with the axis of rotation of the disc, from its first limit position to its second limit position, wherein each shutter is engaged with or engageable with the inner housing.

10. A cassette according to any one of claims 1 to 9, wherein the automatic means for rotating the inner housing from its first limit position to its second limit position against the bias of the inner housing resilient means comprises a drive rod member of the record and/or playback apparatus.

11. A cassette according to claim 10, wherein the outer housing is provided with a hold therein to afford access to the inner housing of the drive rod member.

12. A cassette according to any one of the preceding claims, wherein the inner housing resilient means comprise at least one spring.

13. A cassette according to claim 12, wherein there is at least one spur projecting radially outward from the peripheral rim of the inner housing to which a respective spring is attached, the other end of said spring being attached to the outer housing.

14. A cassette according to claim 13, wherein each spur spring is attached at one end to a respective pin member which extends between the upper and lower inner surfaces of the outer housing.

15. A cassette according to any one of the preceding claims, wherein the inner housing comprises two parts each including a substantially circular surface and a peripheral rim which rims are attached to form the substantially closed inner housing, and wherein the peripheral rim of the inner housing is encircled by a seal strip to secure the two parts of the inner housing and prevent the ingress of dust or dirt, which seal strip lies substantially perpendicular to the plane of the inner housing and which comprises a strip with at least one hole along its length for engaging with a respective spur on the peripheral rim of the inner housing, and a means for securing the two ends of the seal strip.

16. A cassette according to claim 15, wherein the means for securing the two ends of the seal strip comprises a hole in one end of the strip through which the other tail end can irreversibly pass, so that the seal strip is pulled tight around the peripheral rim of the inner housing.

17. A cassette according to any one of the preceding claims, wherein the drive rod member of the record and/or playback apparatus pushes the tail end of the seal strip a fixed distance, to turn the seal strip and thus rotate the inner housing from its first limit position to its second limit position against the bias of the spur springs.

18. A cassette according to any one of the preceding claims, wherein the tail end of the seal strip includes a clip which, when the cassette is not in use, engages with a clip member in the cut out portion of the outer housing to substantially close the cut out portion.

19. A cassette according to claims 9 and 15, wherein the seal strip comprises along its length cut outs which engage with the shutters so that when the inner housing is rotated from its first limit position to its second limit position, each shutter is moved about its respective pivot from its first limit position to its second limit position.

20. A cassette according to any one of the preceding claims, wherein the inner housing is rotatably located within the outer housing by a first set of locating pins which extend between the upper and lower inner surfaces of the outer housing around the peripheral rim of the inner housing thereby to prevent lateral displacement of the inner housing, and a second set of locating pins which extend from the upper inner surface and lower inner surface of the outer housing to engage with the upper outer surface and lower outer surface respectively of the inner housing.

21. A cassette according to claim 20, wherein each locating pin of the second set engages with a respective arcuate rail of fixed length on the outer surface of the inner housing to allow rotation of the inner housing a fixed distance from its first limit position to its second limit position, said fixed distance corresponding to the length of the arcuate rails.

22. A cassette according to claim 20 or 21, wherein each locating pin of the second set extends from the inner surface of the outer housing and passes through a respective shutter to engage with the respective arcuate rail on the outer surface of the inner housing.

23. A cassette according to any one of the preceding claims, wherein the outer housing is provided with means for locating the assembly correctly into a suitable record and/or playback assembly, which means comprise cut outs and holes which engage specifically with members of the assembly.

24. A cassette according to any one of the preceding claims, wherein the outer housing is provided with a read/write identification button.

25. A cassette according to any one of the preceding claims, wherein the rotatable disc is provided at its central hole with a hub, which hub comprises two parts, upper and lower, joined together to grip the disc therebetween, each part having a central hole through which the drive shaft of the record and/or playback assembly can extend.

26. A cassette according to claim 25, wherein the means for securing the two parts of the hub with the disc therebetween comprises hub rivet pins which extend through each hub part and the disc.

27. A cassette according to claim 25 or 26, wherein the hub includes on at least one part, an electronic conductive plate with connecting rails so that the record and/or playback assembly can identify when the drive shaft is in the correct position.

28. A cassette according to any one of the preceding claims, wherein the disc is coated with a chemical oxide for the recording and/or playback of visual and/or audio information.

29. A cassette substantially as herein before described with reference to Figures 1 to 18 of the accompanying drawings.