GB2285966A

GB2285966A - Tape cassette

Info

Publication number: GB2285966A
Application number: GB9400911A
Authority: GB
Inventors: Kwok Kit Li
Original assignee: BICO MAGNETICS Ltd
Current assignee: BICO MAGNETICS Ltd
Priority date: 1994-01-19
Filing date: 1994-01-19
Publication date: 1995-08-02
Also published as: GB9400911D0

Abstract

A tape cassette 10 comprises a housing 12, a pair of tape reels 24, 26 carried within said housing, a length of magnetic tape 19 extending between said reels for recording and/or playback of information, a pair of apertures 80 in a bottom wall of said housing below said reels for external access to said reels by reel engaging means of recording/playback apparatus and a pair of reel receiving recesses 30, 32 defined by walls 34, 38 and 42, 46 respectively which are arranged radially outwardly of the tape reels. The walls permit sufficient lateral movement of the tape reels for them to align with the reel engaging means of the recording/ playback apparatus if initially misaligned. The tape reels are downwardly biased by a spring 66 and include on the peripheries of their bottom flanges 70 protuberances (74, not shown) which engage with ridges 68 formed on the bottom wall of the housing in order to prevent rotation of the tape reels. <IMAGE>

Description

Tape Cassette This invention relates to tape cassettes.

It is known from GB 2261867 to provide a video tape cassette that is particularly well adapted for direct mail advertising and the like. Because the cassette is intended to be used a limited number of times and then discarded, it is desirable that it should be as inexpensive as possible and the known video cassette is constructed with this objective in mind. For example, the video cassette does not include a brake mechanism for restraining rotation of the tape reels when the cassette is not inserted into a recording/playback machine. There may therefore be a tendency for an excess slackness of tape to occur.

In WO88/02916 it has been proposed to provide a video tape cassette having a pair of tape reels supported in recesses in a solid body formed of foamed plastics material. In this document it is proposed that each tape reel has an enlarged upper flange which is serrated and engages a serrated step in the corresponding recess under spring pressure, so as to prevent the reels from rotating. Another tape braking mechanism is proposed in GB 2249779, in which a bottom flange of the tape reel of a video cassette is provided with an annular toothed area arranged to engage a corresponding annular toothed area on the upper surface of the bottom wall of the video cassette housing. In both these proposals, the tape reels are of course mounted for rotation but substantially all lateral movement of the tape reels is apparently prevented. In different stages of the video tape cassette manufacturing process, the cassette is loaded into various production machines which use two spindles to rotate the reels. For example, at the final stage of video tape cassette assembly, the cassette is loaded into a video cassette loading machine where video tape is wound onto the cassette reels. If lateral movement of the tape reels is prevented, the spindles of these production machines may be misaligned with the centres of the tape reels and hence the production machines or tape cassette may be damaged. Moreover, when the assembled tape cassette is loaded into a recording/playback machine by a user, the capstans of the machine may be initially misaligned with the centres of the tape reels and hence again the machine or the tape cassette may be damaged.

In the case of GB 2249779, the annular toothed areas are located close to the central portion of the base of the tape reels. If the tape is pulled accidentally, the reel is likely to tilt up at the edge with consequent disengagement of the toothed area of the reel from that of the housing. Since the outer rim of the reel is smooth, the reel would then be able to rotate and there would be a failure of the braking mechanism.

According to the present invention, there is provided a tape cassette comprising a housing, a pair of tape reels carried within said housing, a length of magnetic tape extending between said reels for recording and/or playback of information, a pair of apertures in a bottom wall of said housing below said reels for external access to said reels by reel engaging means of recording/playback apparatus, and reel locating means arranged radially outwardly of said reels and permitting rotation thereof, the reel locating means being arranged to permit sufficient lateral movement of the tape reels for them to align with the reel engaging means of the recording/playback apparatus if initially misaligned, and the tape reels having downwardly facing portions resiliently downwardly biased into engagement with upwardly facing portions of the housing, the downwardly and upwardly facing portions being shaped in such a manner that rotation of the tape reels is prevented by said engagement thereof.

With such an arrangement, the tape reels are advantageously located in a manner which allows them automatically to correct any initial misalignment with the reel engaging means of recording/playback apparatus, and in a manner which prevents rotation of the tape reels when the tape cassette is not inserted in a recording/playback apparatus.

In order to assist the lateral movability of the tape reels, the downwardly facing portions of the tape reels and/or the upwardly facing portions of the housing may comprise radially oriented ridges. If such ridges are provided on the tape reels or on the housing or on both the tape reels and the housing, then radial or lateral movement of the tape reels is permitted whilst rotation is prevented.

The downwardly facing portions of the tape reels may for example be disposed on the lower surface of a top flange thereof. It is however preferred for these portions to be disposed on a bottom flange of the tape reels, so that the corresponding upwardly facing portions of the housing may be provided on the bottom wall thereof.

Preferably the downwardly facing portions of the tape reels are disposed adjacent to their outer rims.

With such an arrangement, if there is any tendency for the tape reels to tilt onto an outer edge, then the downwardly and upwardly facing portions should remain in sufficient engagement to prevent rotation.

The downwardly and upwardly facing portions may be provided by attaching, for example by adhering, suitable members to the tape reels or the housing. Preferably, however, the downwardly facing portions and/or the upwardly facing portions are integrally formed with the tape reels and the housing, respectively. This will simplify manufacture, particularly if the housing and the reels are moulded from plastics, for example.

In the preferred embodiments, the reel locating means is arranged to permit lateral movement of the tape reels of at least imam. In one embodiment, for example, the total permitted lateral movement is about 3mm so that an average gap of about 1.5mm is provided between the outer periphery of the tape reels and the reel locating means arranged radially outwardly thereof.

Preferably, the total permitted lateral movement of the tape reels does not exceed 6mm, which would give an average gap of about 3mm between the outer periphery of the tape reels and the reel locating means arranged radially outwardly thereof.

It will be appreciated from the above that certain arrangements of the downwardly facing portions are particularly advantageous. Thus, according to another aspect of the present invention, there is provided a tape cassette comprising a housing, a pair of tape reels carried within said housing, a length of magnetic tape extending between said reels for recording and/or playback of information, a pair of apertures in a bottom wall of said housing below said reels for external access to said reels by reel engaging means of recording/playback apparatus, the tape reels having downwardly facing portions resiliently downwardly biased into engagement with upwardly facing portions of the housing, the downwardly and upwardly facing portions being shaped in such a manner that rotation of the tape reels is prevented by said engagement thereof, and the downwardly facing portions of the tape reels being disposed on a bottom flange thereof adjacent to the outer rim of said bottom flange.

A preferred embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a video tape cassette; Figure 2 is a plan view of a lower housing section of the video tape cassette; Figure 3 is an underneath plan view of a tape reel; and Figure 4 is a cross-sectional view of the tape reel seated in the housing.

The video tape cassette 10 includes a housing 12 having an upper housing section 14 and a lower housing section 16, both of one-piece integrally moulded plastic construction. An aperture 18 is provided along the front wall of the housing to allow access to a length of magnetic tape 19. A cover 20 is pivotally mounted to the upper housing section 14 and is urged by a coil spring 22 to cover the aperture 18.

Within the housing 12, a pair of tape reels 24,26 are disposed for rotation about parallel axes and the magnetic recording tape 19 extends between the reels.

The tape reels are located above apertures 80 in the bottom wall of the lower housing section 16.

A pair of recesses 30,32 are provided for locating the tape reels. The recess 30 is defined by an annular wall 34 formed at its upper edge with circumferentially spaced fingers 36 provided on the lower housing section 16, and an annular wall 38 formed at its lower edge with circumferentially spaced fingers 40 provided on the upper housing section 14. The recess 32 is similarly defined by an annular wall 42 formed at its upper edge with circumferentially spaced fingers 44 provided on the lower housing section 16, and an annular wall 46 formed at its lower edge with circumferentially spaced fingers 48 provided on the upper housing section 14. The annular walls 34 and 42 of the lower housing section 16 are interrupted by gaps 50 and 52 respectively to allow passage of the magnetic tape 19. Similarly, the annular walls 38 and 46 of the upper housing section 14 are interrupted by gaps 54 and 56 respectively. The annular walls of the upper housing section are also interrupted by gaps 58 and 60 through which pass opposed arms 62 and 64 of a leaf spring 66 secured to the upper housing section 14 and arranged to act centrally on the respective tape reels 24,26 to urge them downwardly in resilient manner.

Located radially inwardly of the annular walls 34, 42 of the lower housing section 16, there are provided a plurality (four in this embodiment) of radially oriented ridges 68 at circumferentially spaced locations. The tape reels 24,26 are each provided with a lower flange 70 and an upper flange 72 between which the tape may be wound. As seen in Figures 3 and 4, the lower surface of each lower flange 70, which faces downwardly, is formed with a plurality of protuberances 74 disposed in an annular region adjacent to the outer rims of the lower flange 70.

Thus, when the tape cassette is not inserted in a recording/playback machine, the downwardly facing protuberances 74 of the tape reels engage the corresponding upwardly facing ridges 68 of the lower housing section 16 to prevent rotation of the tape reels. The engagement of the respective portions is ensured by the downward resilient bias applied by the spring 66 to the tape reels. Moreover, because the protuberances 74 are provided at the outer rim of the tape reels, rotation will still be reliably prevented even if there is a tendency for the reels to tilt onto a rim caused by pulling on the magnetic tape 19. When the tape cassette is inserted in a recording/playback machine, the capstans of the machine urge the tape reels upwardly whereby the protuberances 74 are disengaged from the ridges 68 and the tape reels are able to rotate, i.e. the braking mechanism is released.

As seen in Figure 4, the lower and upper flanges 70,72 have a diameter A which is less than the internal diameter B of the tape reel receiving recesses 30,32.

Thus, although the tape reels are located such that their central portions are generally above apertures 80 in the bottom wall of lower housing section 16, a certain amount of lateral movement is permitted so that when the tape cassette is inserted in a recording/ playback machine the tape reels can move into alignment with the capstans of the machine. The permitted lateral movement will generally be at least 3mm and preferably not more than 6mm. In this preferred embodiment, the total permitted movement is 3mm, such that dimension B is 3mm greater than dimension A.

It will be appreciated that whilst the preferred embodiment described above is a video tape cassette, the invention is also applicable to other forms of tape cassette, such as e.g. audio tape cassettes.

The dimensions of the tape cassette will vary according to the type of tape cassette (video, audio etc.) and the particular application. In the illustrated embodiment of a video tape cassette, the ridges 68 may typically have a radial length of 6mm and a height of 0.7mm, whilst the protuberances 74 may typically have a radial dimension of 3mm and a height of 0.4mm.

Claims

1. A tape cassette comprising a housing, a pair of tape reels carried within said housing, a length of magnetic tape extending between said reels for recording and/or playback of information, a pair of apertures in a bottom wall of said housing below said reels for external access to said reels by reel engaging means of recording/playback apparatus, and reel locating means arranged radially outwardly of said reels and permitting rotation thereof, the reel locating means being arranged to permit sufficient lateral movement of the tape reels for them to align with the reel engaging means of the recording/playback apparatus if initially misaligned, and the tape reels having downwardly facing portions resiliently downwardly biased into engagement with upwardly facing portions of the housing, the downwardly and upwardly facing portions being shaped in such a manner that rotation of the tape reels is prevented by said engagement thereof.

2. A tape cassette as claimed in claim 1, wherein the downwardly facing portions of the tape reels and/or the upwardly facing portions of the housing comprise radially oriented ridges.

3. A tape cassette as claimed in claim 1 or 2, wherein the downwardly facing portions of the tape reels are disposed adjacent to their outer rims.

4. A tape cassette as claimed in claim 1, 2 or 3, wherein the downwardly facing portions of the tape reels are disposed on a bottom flange thereof.

5. A tape cassette as claimed in any preceding claim, wherein the downwardly facing portions and/or the upwardly facing portions are integrally formed with the tape reels and the housing, respectively.

6. A tape cassette as claimed in any preceding claim, wherein the reel locating means is arranged to permit lateral movement of the tape reels of at least lmm.

7. A tape cassette comprising a housing, a pair of tape reels carried within said housing, a length of magnetic tape extending between said reels for recording and/or playback of information, a pair of apertures in a bottom wall of said housing below said reels for external access to said reels by reel engaging means of recording/playback apparatus, the tape reels having downwardly facing portions resiliently downwardly biased into engagement with upwardly facing portions of the housing, the downwardly and upwardly facing portions being shaped in such a manner that rotation of the tape reels is prevented by said engagement thereof, and the downwardly facing portions of the tape reels being disposed on a bottom flange thereof adjacent to the outer rim of said bottom flange.

8. A tape cassette substantially as hereinbefore described with reference to the accompanying drawings.