MAGNETIC TAPE CARTRIDGE

Abstract: The magnetic tape cartridge according to this invention comprises an outer lid (4) and an inner lid (5) which is rotatably fitted to the outer lid (4) and performs opening or closing motion in association with the outer lid (4) with its guide pins (5b) slidably inserted in a guide groove (6) formed in the cartridge body (3). A groove wall (6a) of the guide groove (6) has a pressing guide wall portion (16) which is adapted to press the guide pin (5b) to push the inner lid (5) against the counterpart side when the outer lide (4) is in the finally closed state.

Description: DESCRIPTION MAGNETIC TAPE CARTRIDGE [Technical Field] This invention relates to a magnetic tape cartridge suitable for a record reproducing apparatus such as a video tape recorder or the like, more specifically to a magnetic tape cartridge provided with an outer lid and an inner lid for protecting the magnetic tape while the tape is not in use. [Background Art] Conventionally, in the magnetic tape cartridge suitable for a record reproducing apparatus such as a video tape recorder or the like, especially a 8mm video tape cartridge, there has been provided an openable lid at a portion where the magnetic tape is exposed out of the cartridge, for preventing dust from adhering to the magnetic tape in storage, because the dust is often a cause of drop-out etc. during reproduction of the record. Figs. 2 to 4 show an example of a magnetic tape cartridge of the conventional type. Fig. 2 shows an external appearance, while Figs. 3 and 4 show its structure in detail. In the magnetic tape cartridge of the type, there is provided, in front of a cartridge body 3 consisting of an upper case 1 and a lower case 2, an openable lid including an outer lid 4 which is pivotally fixed to both side edges of the front portion of the cartridge body 3 and an inner lid 5 which is fitted to the outer lid 4. Both opposite edges of the inner lid 5 are provided with engaging projections 5a. The engaging projections 5a are rotatably inserted into engaging holes 4a formed in the outer lid 4. The outer lid 4 is also provided, at inner faces of its both opposite edges, with pivotal axes 4b which are rotatably fixed between the upper case 1 and the lower case 2. The inner lid 5 is provided with guide pins 5b at both side edges. Said guide pins are slidably inserted into a guide groove 6 formed in the cartridge body 3. With the structure as above described, the guide pins 5b are caused to slide in the guide groove 6 with an opening or closing action of the outer lid 4 thereby enabling the inner lid 5 to be opened or closed. Thus, the outer lid 4 covers the front face of the magnetic tape 7 which is exposed at the front portion of the cartridge body 3. Then, the inner lid 5 is closed relative to the outer lid 4 and the cartridge body 3 to block a gap between the cartridge body 3 and the outer lid 4 , thus covering the back face of the magnetic tape 7 exposed at the front face of the cartridge body 3. As described hereinabove, a trail of the sliding movement of the inner lid 5 is defined by the guide groove 6. Generally the width of the guide groove 6 is formed slightly larger than the diameter of the guide pin 5b to make a smooth sliding movement of the guide pin 5b with the opening or closing action of the outer lid 4. For this reason, the inner lid 5 tends to have a considerable play at the finally closed state of the outer lid 4. When the magnetic tape cartridge is mounted on the video tape recorder or the like, if the front face of the cartridge body 3 is directed downward, as illustrated in Fig. 5, the inner lid 5 moves downward by its own weight and a contact portion 10 of the inner lid 5 with the cartridge body 3 rises over a top face of the upper case 1. Such rise of the contact portion 10 will be a cause of a catch when the cartridge is injected, and may incur disadvantage such as a damage of the inner lid 5 and accordingly a bad injection of the cartridge. [Disclosure of the Invention] In view of the above, it is an object of the present invention to overcome the above described problem and to provide such a magnetic tape cartridge that can eliminate the unfavorable rise of the inner lid in the finally closed state of the openable lid and can prevent occurrence of the bad injection caused by the rise of the inner lid. The above object of the present invention will be achieved by a magnetic tape cartridge comprising; an outer lid which is pivotally fixed to the front portion of a cartridge body to be opened or closed and adapted to cover the front face of a magnetic tape which is exposed at the front face of the cartridge body, and an inner lid which is rotatably fixed to the outer lid to be opened or closed in association with the opening or closing motion of the outer lid with its guide pins slidably inserted in a guide groove formed in the cartridge body, the inner lid coming into contact with the outer lid and the cartridge body when the outer lid is closed, thereby to block a gap between the cartridge body and the outer lid for covering the back face of the magnetic tape which is exposed at the front face of the cartridge body, wherein a wall of the guide groove includes a pressing guide wall portion which pushes the guide pins in a finally closed state of the outer lid to press the inner lid toward the counterpart of the contact. The pressing guide wall portion is preferably formed by making the width of the guide wall gradually reduced toward the position to which the guide pin slides, when the inner lid is closed. [Brief Description of the Drawings] Fig.1 is a sectional side view of the magnetic tape cartridge of a preferred embodiment according to this invention showing the essential part of the structure, Fig. 2 is a perspective view of the exterior of the magnetic tape cartridge, Fig. 3 is an exploded perspective view of the magnetic tape cartridge in Fig. 2 showing the essential part of the structure, Fig. 4 is a sectional view of the magnetic tape cartridge in Fig. 2 showing the essential part of the structure when the openable lid is open, and Fig. 5 is a sectional side view for explaining an inconvenience with the conventional magnetic tape cartridge. [Best Mode for Carrying Out the Present Invention] One example of the magnetic tape cartridge according to the present invention will be in more detail described hereunder. In order to omit a further description, the same reference numerals are used for the components of the magnetic tape cartridge which are similar to those of the conventional cartridge. Fig. 1 is a sectional side view showing the structure of the front portion of the magnetic tape cartridge which is one embodiment according to this invention. An openable lid consisting of an outer lid 4 and an inner lid 5 is attached to the front portion of the cartridge body 3 so as to be freely opened or closed. The outer lid 4 is pivotally fitted to the cartridge body 3 by means of pivotal axes 4b and covers the front face of the magnetic tape (not shown) which is exposed at the front portion of the cartridge body 3. The inner lid 5 is rotatably engaged with the outer lid 4 with its engaging projections 5a inserted in engaging holes 4a formed in the outer lid 4, and performs opening or closing motions in association with the outer lid 4 with its guide pins 5b slidably inserted in a guide groove 6 formed in the cartridge body 3 with the opening and closing operation of the outer lid 4. When the outer lid 4 is closed, both swinging ends 15a and 15b of the inner lid 5 which are farthermost from the engaging projection 5a come into contact with the outer lid 4 and the cartridge body 3. Thus the inner lid 5 blocks a gap 14 between the cartridge body 3 and the outer lid 4, and at the same time, covers the back face of the magnetic tape (not shown) exposed at the front face of the cartridge body 3. Further, in the magnetic tape cartridge of this embodiment, the groove 6 is defined by the groove walls for regulating the open and close movement of the inner lid 5. One of the groove wall 6a which regulates the closing motion of the inner lid 5 has a pressing guide wall portion 16. The pressing guide wall portion 16 presses the guide pin 5b in a finally closed state of the outer lid 4 thereby to positively push the swinging ends 15a and 15b of the inner lid 5 against the counterpart outer lid 4 and the cartridge body 3 into contact therewith. More specifically, the pressing guide wall portion 16 is formed at a position swollen from the conventional groove wall 6b as shown by a two-dotted line in Fig. 1. In order to form this pressing guide wall portion 16, the width of the guide groove 6 is gradually reduced toward the position to which the guide pin 5b slides (downward in Fig. 1) in the closed state of the inner lid 5. An angle of elevation $of the pressing guide wall portion 16 is, in this case, set at 45° or more. By thus providing the pressing guide wall portion 16 in the guide groove 6, it is possible to forcibly press the inner lid 5 against the counterpart outer lid 4 and the cartridge body 3 in the finally closed state of the outer lid 4, whereby the play in the finally closed states of the outer lid 4 and the inner lid 5 composing the openable lid can be totally eliminated. Because the pressing guide wall portion 16 presses the guide pin 5b only when the outer lid 4 is in its finally closed state, the smooth sliding movement of the guide pin 5b in association with the opening or closing motion of the outer lid 4 will not be hindered. Therefore, the unfavorable rise of the inner lid 5 as shown in Fig. 5 can be avoided and hence the damage of the inner lid 5 as well as the bad injection of the cartridge can be prevented. Further, the pressing guide wall portion 16 is simply formed at the position swollen from the conventional groove wall 6b and can be easily produced by cutting a thickness in a part of a metal mold when the cartridge is manufactured by resin molding. Therefore, a substantial rise of the production cost can be avoided. [Industrial Applicability] As described hereinabove, with the magnetic tape cartridge according to the present invention, the inner lid can be forcibly pressed against the counterpart outer lid and the cartridge body at the finally closed state of the outer lid. Therefore, the play in the openable lid in its finally closed state is completely eliminated and the rise of the inner lid over the top face of the cartridge body is thus prevented, whereby such inconveniences as a damage of the inner lid or a bad injection of the cartridge, etc. can be avoided. While there has been described in connectionwith the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is aimed, therefore, to cover in the appended claim all such changes and modifications as fall within the true spirit and scope of the invention.

Claims: CLAIMS 1. A magnetic tape cartridge comprising: an outer lid (4) pivotally fixed to a front portion of a cartridge body (3) to be opened or closed and adapted to cover a front face of a magnetic tape (7) which is exposed at the front face of said cartridge body, and an inner lid (5) rotatably fixed to said outer lid (4) to be opened or closed in association with the opening or closing motion of said outer lid (4) with its guide pins (5b) slidably inserted in guide grooves (6) formed in the cartridge body (3) respectively, said inner lid ( 5 ) coming into contact with the outer lid ( 4 ) and the cartridge body ( 3 ) when the outer lid ( 4 ) is closed, to thereby close a gap (14) between the cartridge body (3) and the outer lid ( 4 ) while covering the back face of said magnetic tape (7), wherein walls respectively defining said guide grooves (6) include pressing guide wall portions (16) which press the guide pins (5b) in a finally closed state of the outer lid (4) to push the inner lid (5) in a predetermined direction. 2. The magnetic tape cartridge according to claim 1 , wherein said pressing guide wall portions (16) press said inner lid (5) in a direction where said inner lid (5) is rotated toward said cartridge body ( 3 ) . 3. The magnetic tape cartridge as claimed in claim 1 , wherein each of said pressing guide wall portions (16) is formed by reducing the width of said respective guide groove (6) toward a position to which the respective guide pin (5b) slides when the inner lid (5) is closed. 4. The magnetic tape cartridge as claimed in claim 2, wherein each of said pressing guide wall portions ( 16 ) is formed by reducing the width of said respective guide groove (6) toward a position to which the respective guide pin (5b) slides when the inner lid (5) is closed. 5. The magnetic tape cartridge as claimed in claim 1 , wherein said pressing guide wall portions (16) press the guide pins (5b) in a finally closed state of said outer lid (4) to thereby positively push swinging ends (15a and 15b) of said inner lid (5) against said outer lid (4) and said cartridge body (3) into contact therewith.

Inventors: TAKAHASHI DAISUKE, TSUYUKI SEIJI, TAKAHASHI, DAISUKE, TSUYUKI, SEIJI
Applicants: FUJI PHOTO FILM CO LTD, TAKAHASHI DAISUKE, TSUYUKI SEIJI, FUJI PHOTO FILM CO., LTD., TAKAHASHI, DAISUKE, TSUYUKI, SEIJI
Application year: 1999
Main classification: G11B23
IPC codes: G11B23