Cassette case

Abstract: A cassette cartridge comprising a first casing shell (6) having a recess (11) formed proximate a side wall portion thereof and a second casing shell (7) matingly fitting with the first casing shell (6). The second casing shell (7) has a projection (10) formed at a location corresponding to the recess formed in the first casing shell such that a dimension of a surface of the projection (10) contacting a bottom of the recess (11) is less than a corresponding dimension of the bottom of the recess (11) so that on joining the two shells welding burrs may be contained.

Description: The present invention relates generally to a cassette cartridge. Specifically, the present invention relates to a cartridge, e.g. for tape or a disc, in which the casing is adapted so as to prevent problems associated with the construction process. Various types of tape or recording medium containing cartridge are well known in the art e.g. those which contain reels of magnetic tape, such as compact cassettes, and microcassettes, for example, or other types of tape cassette e.g. ink ribbons etc or cassettes for discs. Tape cassettes, for example, usually employ a casing comprising upper and lower halves which are mutually joined for rotatably mounting tape supply and take-up reels, holding a length of magnetic tape, therein. The casing is generally formed of synthetic resin and the halves thereof are joined by ultrasonic welding, or the like. In the accompanying drawings, for example, a conventional tape cartridge is shown in Figs. 5 and 6. As can be seen in the drawings, the conventional cartridge 100 comprises an upper casing 103 and a lower casing 104. The upper casing 103 has a substantially planar upper surface 101a and a lower side wall portion 102a projecting downwardly around the periphery of the upper surface 101a. Correspondingly, the lower casing 104 has a substantially planar lower surface 102b and an upper side wall portion 101b projecting upwardly around the periphery of the lower surface 101a. The casing is formed such that the lower wall side portion 102b of the upper casing 103 mates with the upper side wall portion 101b of the lower casing 104 via abuting surfaces 107 forming the facing sides of each of the wall portions 102a and 101b. As can further be seen in Fig. 5, the abuting surfaces portions 107 of the upper side wall portion 101b of the lower casing 104 are provided with energy directing ribs 105 to facilitate joining of the upper and lower halves 103, 104 of the cartridge 100 by, for example, ultrasonic welding, or such similar process. Referring to Fig. 6, a cross-sectional view of a portion of the upper and lower casings 103, 104 in a joined state is shown. As can be seen in the drawing, after joining of the upper and lower halves 103, 104 has been carried out, a burr 106 projecting inward and outwardly around the periphery the joined upper and lower casings 103, 104, is formed. As may be seen in Fig. 6, the joined halves 103, 104 of the casing are of subtantially the same height H. The burr 106 corresponds to a center line T at the seam where the upper and lower casing halves 103, 104 mate. In such conventional cartridge casings however, drawbacks are present in that the burr 106, projects into the interior of the cartridge casing around the periphery of the casing interior, especially at corners of the casing where a substantially large burr may be formed. The burr 106 is generally located at a center line T of the casing interior, and can cause damage to the tape during winding and playing operations thereof. This in turn may cause spoilage of products during production and dissatisfaction among the users. This is particularly true during the actual welding process when the burr is formed, as the melted resin may cause damage during production. Also, the presence of such a burr limits the amount of tape which can be accomodated by the tape reels mounted within the cartridge casing. It is therefore a principal object of the present invention to overcome the drawbacks of the prior art. According to the present invention there is provided a cassette cartridge containing a recording medium, the cartridge comprising: a first casing shell having a planar portion and with joined thereto a side wall portion having a first abutment surface on an end thereof opposite the end joining said planar portion; a second casing shell, having a planar portion and a side wall portion including a second abutment surface corresponding to that of said first casing shell, characterized in that said first casing shell has a recess formed in said planar portion proximate said side wall portion thereof, and said second casing shell has a projection formed at a location corresponding to said recess formed in said first casing shell, a dimension of a surface of said projection to contact a bottom of said recess being less than a corresponding dimension of said bottom of said recess. According to another aspect the invention provides a method for manufacturing a cassette cartridge as above, comprising the steps of forming said recess proximate said side wall portion of the first casing shell; forming said projection at a location corresponding to said recess, a dimension of a surface of said projection to contact a bottom of said recess being less than a dimension of said bottom of said recess; positioning cassette contents between said first and second casing shells and joining said first and second casing shells while melting said surface of said projection. The contents may be first and second reels positioned between the first and second casing shells so as to be rotatably mounted therebetween according to joining of the first and second casing shells and the method includes providing tape between the first and second reels and affixing ends thereof to the first and second reels to be wound therebetween according to rotation of the reels. Thus with the invention the halves of a casing thereof may be joined while formation of a burr at a joining seam therebetween where it may impede the cartridge contents is prevented. The invention can also provide a cartridge in which the contents are protected from a burr formed during a welding process for joining halves of the cartridge casing. The invention will be further described by way of example only with reference to the accompanying drawings, in which:- Fig. 1 is a perspective view of a recording medium containing cartridge according to the invention; Fig. 2 is a perspective view of a lower half of a cartridge casing of the recording medium containing cartridge of Fig. 1; Fig. 3 is a perspective view of an upper half of the cartridge casing of the recording medium containing cartridge of Fig. 1; Fig. 4 is a cross-sectional view of a joined portion of the upper and lower halves of the casing of the recording medium containing cartridge of the invention; Fig. 5 is an exploded perspective view of a conventional recording medium containing cartridge; and Fig. 6 is a cross-sectional view of a portion a casing of the conventional recording medium containing cartridge of Fig. 5 for explaining a problem associated with the prior art. Referring now to the drawings, particularly to Fig. 1, a first embodiment of a recording medium containing cartridge according to the invention will be described as applied to a tape cartridge containing a magnetic tape wound therein as a recording medium, although any other type of recording medium may further be utilized. A tape cartridge according to the first embodiment includes casing 5 comprising an upper shell 6, and a lower shell 7. The upper shell 6 includes a substantially planar upper surface portion 8a and a side wall portion 9a extending perpendicularly downward from the upper surface portion 8 at peripheral edges thereof. The side wall portion 9a further includes an abuting surface 21 at a lower side thereof. Likewise, the lower shell 7 includes a substantally planar lower surface portion 8b and a side wall portion 9b extending perpendicularly upward from the lower surface portion 8b at peripheral edges thereof. The side wall portion 9b includes an abuting surface 20 at an upper side thereof, facing the abuting surface 21 of the upper shell. In addition, as best seen in Fig. 2, the lower shell 7 has, at each corner thereof, an L-shaped projection 10 is formed parallel to, and extending higher than, the side wall portions 9b, at the inside thereof. The L-shaped projections 10 correspond to recessed portions 11, best seen in Fig. 3, which are formed at each corner of the underside of the upper surface portion 8a of the upper shell 6, at a location inside of the side wall portions 9a, so as to receive the L-shaped projections 10 of the lower casing 7 to facilitate joining of the upper and lower shells 6 and 7. Referring again to Fig. 1, in a joined condition, the upper and lower shells 6 and 7 form a cartridge casing 5 rotatably mounting a supply reel 3 and a take-up reel 4 therewithin. The supply and take-up reels 3 and 4 accommodate a wound length of magnetic tape 2 thereon. Referring again to Fig. 2, a perspective view of the upper and lower shells 6 and 7 is shown in a state wherein the upper and lower shells 6 and 7 are separated from each other. As can be seen in the drawing, in addition to the above, the lower shell 7 includes, along the abuting surface 20 of the side wall portions 9b, and the edges of the L-shaped projections 10, respectively, welding ribs 13 and 14. Now, referring to Fig. 4, a cross-sectional view of a corner portion of the casing shells 6, 7 are shown in a joined condition, with engagement of the L-shaped projection 10 of the lower shell 7 in the recess 11 of the upper shell 6. As can be seen, the recess 11 has a depth D of, for example, 0.3mm, in the case of a standard size compact cassette type cartridge. Further, a width of the L-shaped projection is less than that of the recess 11 by a predetermined amount, leaving a gap G. Before welding, the L-shaped projections 10, have a length longer than can be accomodated by the recess 11, 0.5mm for example, when welding processing is carried out, melting of the welding ribs 13 of the side wall portions 9b and welding ribs 14 at the top of the L-shaped projections 10 occurs and the upper and lower shells 6 and 7 are joined. At this time, the molten portion (including the welding rib 14) of the top of the L-shaped projection 10 is moved by the joining pressure of the upper and lower shells 6 and 7 forming a burr 12 in the gap G, and the abuting portions 20 and 21 of the lower and upper shells 7 and 6 are joined thus the height of the L-shaped projection becomes reduced to be accommodated by the depth D of the recess 11. As seen in the drawing, the burr 12 formed in the welding process is contained in the recess 11 and cannot come into contact with the tape 2 disposed in the cartridge casing 5. Thus according to the above-described embodiment, the halves of a cartridge casing may be joined while fully protecting the tape therein from formation of a burr at corners of the casing during welding processing. Further, althought the above-described embodiment provides the L-shaped projections in the lower shell 7 and the recesses 11 in the upper shell, this may be reversed, that is the projections 10 may be provided in the upper shell 6 and the recesses in the lower shell 7 or, each of the upper and lower shells may be provided with a corresponding combination of projections and recesses. Also, although in the present embodiment, the projections are L-shaped and provided in corner portions of the cartridge casing, the projections 10 may alternatively be square, pin shaped, or rectangular and provided at any location along the side walls of the cartridge casing so long as the opposing shell of the casing is formed with an appropriate recess for accepting same. For example, enlongated projections 10 may be provided along the top and each side of the cartridge casing for preventing a burr from intruding into the casing at any portion thereof. It will be noted that the size of the projection 10 and the depth of the recess 11 as well as the dimension of the gap G is further adaptable depending on the type of casing and degree of welding to be performed. Thus, although the drawings show a standard size, compact audio-type cartridge accommodating magnetic tape thereon, the present invention may be applied to any type of cartridge structure including microcassettes, video cassettes, magnetic and optical disks, digital audio cassettes as well as cartridge type ink ribbon cartridges, typewriter ribbons, head cleaning tapes and the like. While the present invention has been disclosed in terms of the preferred embodiment in order to facilitate better understanding thereof, it should be appreciated that the invention can be embodied in various ways without departing from the principle of the invention. Therefore, the invention should be understood to include all possible embodiments and modification to the shown embodiments which can be embodied without departing from the principle of the invention as set forth in the appended claims.

Claims: A cassette cartridge containing a recording medium, the cartridge comprising: a first casing shell (6) having a planar portion (8a) with joined thereto a side wall portion (9a) having a first abutment surface (21) on an end thereof opposite the end joining said planar portion (8a); a second casing shell (7), having a planar portion (8b) and a side wall portion (9b) including a second abutment surface (20) corresponding to that of said first casing shell, characterized in that said first casing shell (6) has a recess (11) formed in said planar portion (8a) proximate said side wall portion (9a) thereof, and said second casing shell (7) has a projection (10) formed at a location corresponding to said recess (11) formed in said first casing shell (6), a dimension of a surface of said projection (10) to contact a bottom of said recess (11) being less than a corresponding dimension of said bottom of said recess (11). A cassette cartridge as set forth in claim 1, wherein said side wall portions (9a,9b) extend substantially perpendicularly from outer peripheries of said planar portions (8a,8b) respectively of said first and second casing shells (6,7) respectively. A cassette cartridge as set forth in claim 1 or 2, wherein said projection (10) and said recess (11) are L-shaped. A cassette cartridge as set forth in claim 1, 2 or 3, wherein said projection (10) and said recess (11) are provided in each corner of said cartridge. A cassette cartridge as set forth in claim 1, 2, 3 or 4, wherein said first and second abutment surfaces (20,21) of side wall portions (9a,9b) of one of said first and second casing shells (6,7) are provided with welding ribs (13). A cassette cartridge as set forth in any one of the preceding claims, wherein a top surface of said projection (40) comprises a welding rib (14). A cassette cartridge as set forth in claim 5 or 6, wherein the difference between the dimensions of the projection (10) and the recess (11), due to said surface of said projection (10) being smaller than said bottom of said recess (11), takes the form of a gap whose size is determined so as to contain a burr formed by melting of said welding rib. A cassette cartridge as set forth in any one of the preceding claims, wherein a length of said projection (10) is slightly greater than can be accommodated by a depth of said recess (11). A cassette cartridge as set forth in any one of the preceding claims, wherein the difference between the dimensions of the projection (10) and the recess (11), due to said surface of said projection (10) being smaller than said bottom of said recess (11), takes the form of a gap (G) at one side of said recess (11) when said projection (10) is inserted therein on joining of said first and second casing halves (6,7). A cassette cartridge as set forth in claim 9, wherein said gap (G) is present at an inner side of said recess (11). A cassette cartridge as set forth in any one of the preceding claims, containing a recording medium of magnetic tape wound between two reels, or a magnetic, optical or m/o disc, rotatably mounted between said first and second shells (6,7). A method of manufacturing a cassette cartridge according to any one of the preceding claims, comprising the steps of: forming said recess (11) proximate said side wall portion (9a) of the first casing shell (6); forming said projection (10) at a location corresponding to said recess (11), a dimension of a surface of said projection (10) to contact a bottom of said recess (11) being less than a dimension of said bottom of said recess (11); positioning cassette contents between said first and second casing shells and joining said first and second casing shells (6,7) while melting said surface of said projection (10).

Inventors: SHIMOKUNI KENJI, SHIMOKUNI, KENJI, SHIMOKUNI, KENJI, C/O SONY CORPORATION
Applicants: SONY CORP, SONY CORPORATION
Application year: 1992
Main classification: G11B23
IPC codes: G11B23