TAPE CASSETTES

Abstract: An end-less loop, tape cassette (10) contains wound tape (12) with no spool or equivalent rotatable part at the centre of the windings.

Description: TAPE CASSETTES TECHNICAL FIELD The present invention relates to tape cassettes. More particularly, but not exclusively, this invention relates both to tape cassettes which can be used for playing of magnetically recorded audio or computer tapes, and also to tape cassettes which can be used for recording and playing of such tapes. BACKGROUND ART In a typical end-less loop tape cassette, a wound tape extends from a single spool past a pressure surface such as a pressure pad and past a pinch surface provided for example by a pinch wheel, back to the windings on the spool. It is usually arranged that a drive capstan on a tape cassette machine pinches the tape at the pinch wheel and by rotatation serves to drive the tape over the pressure pad. At the pressure pad, the moving tape is then located in operative conjunction with a tape head assembly of the tape casssette machine, thereby permitting recording and/or playing of the tape. The tape normally forms a series of windings around the spool. The tape is then pulled out from the innermost winding and driven back to form the outermost winding. The spool, or more generally an equivalent rotatable part at the centre of the windings, rotates to facilitate the unwinding and rewinding while the tape is being driven at the pinch wheel. DISCLOSURE OF INVENTION In accordance with the present invention there is provided an end-less loop, tape cassette which contains wound tape with no spool at the centre of the windings. As a practical point, there is often a frictional limit to the length of tape which can be included in an end-less loop tape cassette without a spool or equivalent rotatable centre, but for any given construction this practical limit can easily be determined by trial-and-error. It suffices to say for example that there is no difficulty in constructing a spool-less cassette containing about 15 to 20 metre or more of magnetically coated tape which is adequate to record several minutes of music or one or more programs for a microcomputer. Thus, in a preferred aspect, the present invention provides an end-less loop, spool-less cassette containing up to 15 or 20 metre of magnetically coated tape. The tape in the cassettes of this invention suitably has a transverse width of up to 4mm, though for preference the width is from 1mm to 2mm. Reflecting the limited size of the tape, the cassettes of this invention can be made relatively small, with typical overall dimensions for a rectangular cassette of from 25mm to 50mm by ldmm to 30mm by 1mm to 4mm. Indeed, it is an exceptional advantage of the present invention that a functional tape cassette can be made which, for example, is about 35mm by about 20mm by about 2mm. The extreme thinness of such a cassette is only a practical possibility because of the absence of the parts needed to constitute a rotating spool. The present invention can ' therefore provide- a truly miniature tape cassette. The cassettes of this invention will usually be designed such that ' the tape is pulled past the tape head assembly by downstream engagement between the drive capstan and a pressure surface in the cassette. To this end, the cassettes preferably have the loop of tape leading from an innermost winding to a window for receipt of a tape head assembly, there being a pressure surface positioned at the window inwardly of the tape, and the tape then returning to the outermost winding after passing a drive window and associated pinch surface. Typically the pressure surface takes the form of a pressure pad, and typically the pinch surface takes the form of a pinch wheel. If desired, the tape head window and the drive window can be united as a single window. Guide surfaces can usefully be included of a shape and configuration designed to ease the transport of the tape. The cassettes usually have rectangular major faces with the axis of the tape windings extending perpendicularly to them. The windings will normally be displaced towards one end of the cassette, with separate or combined windows for the tape head assembly and the drive capstan preferably being formed in an opposite, short edge of the cassette. Furthermore, the cassettes of this invention preferably have a fixed hub about which the tape is wound, with the end-less loop typically being taken out from the innermost winding at the fixed hub and then returned to the outermost winding. The fixed hub can for example be a solid hub of generally frustoconical section, and suitably has a rounded edge forming the transition from the conical surface to the major base. A fixed hub of generally frustoconical configuration can facilitate the leading out of the wound tape, although other configurations are envisaged which- serve to guide the tape. To the same end, an off-take guide channel can be provided on a wall of the cassette adjacent the wound tape. More generally, the fixed hub can be constituted by one or more parts which serve to define a fixed centre about which the tape can be wound. In passing out over the windings, the tape usually travels in a plane perpendicular to the axis of the windings. It is then preferred to include guide surfaces which serve to impart a twist to the tape such that it is -restored to the same orientation as the wound tape and can eventually rejoin the windings. Suitable guide surfaces for imparting twist comprise a pre-twist deflector which lies across the path of the tape and serves to position the tape parallel to the adjacent major walls of the cassette and at about the mid-point between the major walls, together with a post-twist guide perpendicular to the major walls, and thus parallel to the axis of the tape windings. In passing from the deflector to the guide, the tape is rotated through 90°. One or more guides can be provided to encourage proper transport of the tape back to the windings. For example, an outer guide face can be positioned at the pinch wheel or other pinch surface to maintain the tape adjacent the wheel, a guide channel can be provided to act as a conduit to lead the tape from the pinch surface to the windings, and a wind-on guide can be provided to ensure that the tape is properly positioned as it winds back on to the windings. Other steps can be taken to ensure smooth running of the tape. For instance, the tape can be coated on. the non-playing face with a low-friction coating. The adjacent surfaces of the cassette housing and/or hub can be similarly coated, or films of low-friction material can be interposed between the tape and cassette parts. Moreover, experimentation with the geometry of the various components can give improvements in the free running of the tape. In use, the cassettes of this invention are brought into operative association with one or more transducers of a tape head assembly of a tape cassette machine. For preference, the cassettes include cooperating surfaces dimensioned and arranged to cooperate with engagement mechanism provided on the tape cassette machine. By way of example, the cassette cooperating members can include an abutment face providing a pinch surface on which the engagement mechanism can bear to move the cassette to the transducer head. In particular, the cooperating members can be notches or other forms of recess at the sides of the cassette. The cassettes can also include alignment surfaces for ensuring alignment of the cassette relative to the transducer head. Such alignment surfaces can suitably take the form of .channels extending along the sides of the cassette, and are also suited for spooled cassettes. A tape cassette machine suitable for playing the cassettes of this invention can easily be devised by the skilled man, making use of available components. As such, a full understanding of the present invention does not demand a detailed description of a suitable machine. By way of illustration of the potential of the present invention, the reader is referred to the specification of patent application PCT/GB 84/00362. The tape cassette machine shown in the drawings of that specification is a portable machine and can readily take full advantage of the exceptionally small size of the cassettes of the present invention. However. the cassettes of the present invention can be used with other designs of tape machine equipped with a suitable tape head assembly and drive capstan. When the tape cassette is in operative association with the tape head assembly of a tape cassette machine, the tape is transported past the one or more transducers typically by engagement of the pinch wheel with a rotating capstan drive of the machine. DESCRIPTION OF DRAWINGS An illustrative embodiment of the present invention will now be described by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 is an elevational view of a major face of a cassette of this invention; Figure 2 is a sectional view taken on the line 2-2 of Figure 1; Figure 3 is a sectional view taken on the line 3-3 of Figure 1; Figure 4 is a sectional view taken on the line 4-4 of Figure 1; and Figure 5 is an elevational view of an end face of the cassette of the previous Figures. BEST MODE Referring first to Figure 1, a cassette 10 in accordance with this invention is an end-less loop cassette without a spool. Conventionally, an end-less loop cassette has 5 a spool, that is, a rotatable reel, on which the tape is wound. The present cassette does not have a rotatable part at the centre of the windings. The cassette shown in the drawings is intended for audio . or computer use, and comprises an end-less loop of about 108 metre of tape 12 housed in a plastics housing 14. The tape 12 is a polyester tape coated with magnetic particles in conventional manner on one face and with a slip coating on the other face. The tape has a thickness of about 0.003mm and a transverse width of 15 about 1.65mm. The housing 14 itself is about 32mm by about 19mm by about 2.5mm thick. Thus, the cassette 10 is a miniature cassette. The tape 12 is wound around a fixed, non-rotatable hub 16 shown in section in Figure 2. In this instance, the 20 fixed hub 16 is f ustoconical and extends between major walls 18 and 20 of the housing 14, though this is not essential. A rounded edge 22 forms the transition from the conical surface to the major base of the hub located .at wall 18 of the housing. The height of the fixed hub 2516 is marginally greater than the transverse width of the tape 12, such that the innermost winding of the tape is retained in position by the edge 22 and can be led out over the wound tape to an off-take guide channel 24 shown in section in Figure 4. 30 The off-take guide channel 24 includes a guide face 26 which is spaced from the wall 20 by about the transverse width of the tape, such that the tape readily passes out 1 over the winding of tape remaining around the fixed hub 16. The tape is led out generally tangentially to the hub and extends parallel from the off-take guide channel 24. The tape 12 is taken past a pre-twist deflector 28 which lies across the path of the tape and serves to position the tape at about the mid-point between the major walls 18, 20 of the housing. A fixed corner pin 30 in the housing forms a post-twist guide surface parallel to the axis of the fixed hub 16 and thus parallel to the axis of the tape wound about the hub. In passing from the -deflector 28 to the pin 30, the tape receives a half-twist such that it is rotated through 90°. At the corner pin 30 the tape has assumed a position parallel to the hub axis. The tape 12 then passes to a window 32 formed in the end face 34 of the housing 14. There is a pressure pad 36 of foam material at the window, inwardly of the tape, such that the tape is resiliently presented at the window for operative association with a tape head assembly of a tape playing machine, not shown. From the window 32 the tape then passes around a pinch wheel 38 with an associated window 40 for operative engagement with a drive capstan of the tape playing machine. Thereafter the tape extends back to the hub to rejoin the windings approximately tangentially and form the outermost winding around the hub. A curved guide face 42 and a guide channel 44 formed between walls 46, 48 help to ensure safe return of the tape to the hub, as also does a wind-on guide 58 at the point where the tape winds back on to the windings about the hub 16. As shown in Figure 1, the housing 14 includes side notches 50, 52 which are provided for engagement by a pull-in mechanism on the tape playing machine. The pull-in mechanism serves to pull the cassette 10 towards the tape head assembly and drive capstan to achieve transport of the tape past the tape head for recording on to the tape or play back from the tape. In this instance the housing also includes side channels 54, 56 which help in positioning of the cassette in the tape playing machine. As an aid to rotation of the tape windings about the fixed hub 16, the adjacent areas of the major walls 18 and 20 and the hub 16 itself can have a low friction coating. Alternatively a low friction film can be interposed between the tape windings and the adjacent parts. As will be apparent from -the drawings, the sides of the cassette are longer than the ends, such that the windows 32, 40 are formed in a shorter edge face of the cassette and the notches 50, 52 are formed in a longer edge face of the cassette. The miniature cassette 10 of this invention is exceptionally small size and yet is easy to manufacture on a large scale at low unit cost, stemming principally from the ■ presence of the fixed hub 16 rather than a spool or other rotatable centre. There are considerable difficulties in assembling a spooled miniature cassette, and furthermore during use there is a tendency for the spool to be pulled out ' of axial alignment. INDUSTRIAL APPLICABILITY The miniature cassette 10 shown in the drawings has been used experimentally both to record music which was successfully played back, and thereafter also to record a computer program which was successfully loaded into a microcomputer.

Claims: CLAIMS 1. An end-less loop, tape cassette (10) which contains wound tape (12) with no spool at the centre of the windings. 2. An end-less loop, tape cassette (10) containing up to 20 metre of magnetically coated tape (12) which unwinds from a tape winding without a central spool, leads to a position (32) for receipt of a tape head assembly, and then returns to the winding. 3. A cassette according to claim 1 or 2, with a fixed hub (16) about which the tape is wound. 4. A cassette according to any preceding claim, wherein the end-less loop is taken out from the innermost winding and then returned to the outermost winding. 5. A cassette according to claim 4, with one or more guide surfaces (26, 28, 30, 42, 44, and/or 58) for guiding the tape (12) out from the winding and then back to the winding. 6. A cassette according to * any preceding claim, with a window (32) for receipt of a tape head assembly and with a pressure surface (36) positioned at the window (32) inwardly, of the tape. 7. A cassette according to any preceding claim, with a window (40) for receipt of a capstan drive and with a pinch surface (38) positioned at the window (40) inwardly of the tape. ■ 8. A cassette acco ding to claim 6 or 7, wherein the window (32) for receipt of a tape head assembly and/or the window (40) for receipt of a capstan drive is formed in a shorter edge of the cassette. 9. A cassette according to any preceding claim, which includes cooperating surfaces (50, 52) dimensioned and arranged to cooperate with engagement mechanism provided on a tape cassette machine. 10. A cassette according to any preceding claim, which includes alignment surfaces (54, 56) for ensuring alignment of the cassette relative to the transducer head of a tape head assembly.

Inventors: MURPHY TERENCE WALTER DANIEL, MURPHY, TERENCE, WALTER, DANIEL
Applicants: MADSU UK LTD, MADSU UK LIMITED
Application year: 1985
Main classification: G11B23
IPC codes: G11B23