Patent Publication Number: US-6981586-B2

Title: Magnetic tape cassette storage case

Description:
This is a divisional of application Ser. No. 09/856,817 filed May 25, 2001 now U.S. Pat. No. 6,550,614, which is a §371 of International Application No. PCT/JP99/06624 filed Nov. 26, 1999; the above noted prior applications are all hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a magnetic tape cassette storage case for storing a magnetic tape cassette. 
     BACKGROUND ART 
     Various types of storage cases for magnetic cassette tapes (herein after referred to as storage case) are proposed according to the configuration of the magnetic cassette to be stored. Referring now to  FIG. 46  and  FIG. 47 , a storage case for digital video cassettes (hereinafter referred to as “DVCs”) and a magnetic tape cassette for the DVCs of the related art will be described by way of example. 
     The storage case  1441  shown in  FIG. 46  comprises a storage section  1443  for storing the magnetic tape cassette  1481  shown in  FIG. 47 , a lid section  1445 , and a connecting section  1447 . The storage section  1443  comprises a first plate portion  1451 , and a first sidewall portion  1453  formed integrally along the outer periphery of the first plate portion  1451 , and a pair of reel locking ribs  1445   a ,  1445   b  formed on the first plate portion  1451  at the positions somewhat closer to the rear side than to the front side. When the magnetic tape cassette  1481  shown in  FIG. 47  is stored, it will be fitted within the first sidewall portion  1453  in the state shown by a phantom line in  FIG. 46  when it is properly stored. 
     The lid section  1445  comprises a second plate portion  1461 , and a second sidewall portion  1463  formed integrally along three sides of the outer periphery of the second plate portion  1461 . The connecting section  1447  comprises a third plate portion  1471  and thin portions  1473   a ,  1473   b  formed on both sides thereof. These thin portions  1473   a ,  1473   b  enable the storage section  1443  and the lid section  1445  to close as a book. 
     Outside of the first sidewall portion  1453  that defines the storage section  1443 , there is provided an overhanging portion  1451   a  that is formed by a part of the first plate portion  1451  in an overhanging manner. Therefore, even when the storage section  1443  and the lid section  1445  are closed and the second sidewall portion  1463  of the lid section  1445  is fitted around the first sidewall portion  1453  of the storage section  1443 , the overhanging portion  1451   a  prevents the storage section  1443  from getting into the lid section  1445 , and thus the thickness of the case may be maintained as a whole. 
     There are formed a recess  1453   a , or a locked portion, on the outer surface of the fist sidewall portion  1453 , and a projection  1463   a , or a locking portion, on the inner surface of the second sidewall portion  1463  at the position corresponding to the recess portion  1453   a  when the storage section  1443  and the lid section  1445  are closed. Therefore, when the storage section  1443  and the lid section  1445  are closed with respect to each other, the projection  1463   a  and the recess  1453   a  engage so as to prevent an accidental opening of the storage section  1443  and the lid section  1445 . 
     Referring now to  FIG. 47 , the magnetic tape cassette  1481  will be described.  FIG. 47  is a perspective view of the magnetic tape cassette  1481  when viewed from the bottom side, in which an upper cassette half  1483  is situated below the lower cassette half  1485 . There are formed circular openings  1487   a ,  1487   b  at two locations on the lower cassette half  1485 , and engaging portions  1489   a ,  1489   b  integrally formed with the reel hubs (not shown) on which the magnetic tape is wound are exposed therefrom. 
     The engaging portions  1489   a ,  1489   b  have a function to unwinding and winding the magnetic tape when it is mounted in the VTR, and a function to engage the ribs  1455   a ,  1455   b  for engaging the reel and prevents rattling of the magnetic tape cassette  1481  when it is stored in the storage case  1441 . 
     On the front side of the magnetic tape cassette  1481 , an outer lid  1491  is provided for pivotal movement, and when it is mounted in the VTR or the like, the magnetic tape is pulled out after the outer lid  1491  is pivoted as shown by the arrow A in  FIG. 47 . There is formed a recessed opening  1493  inside the outer lid  1491  at near the center in such a manner that the upper and lower cassette halves  1483 ,  1485  are notched, and there is provided a shoulder  1495  on one end of the opening  1493  on the side of the lower cassette half  1485 . 
     The magnetic tape cassette  1481  may be stored in the storage case  1441  by fitting the magnetic tape cassette  1481  in the sidewall portion  1453  as shown by a phantom line in  FIG. 46 , and pushing and inserting the ribs  1455   b ,  1455   a  for engaging the reels into circular engaging holes B formed at the center of the engaging portion  1489   a ,  1489   b , whereby the positional restriction of the magnetic tape cassette  1481  is made and stored appropriately. 
     However, in the structure of the storage case  1441  described above, the following problem was recognized when the magnetic tape cassette  1481  is stored. When the storage section  1443  and the lid section  1445  are closed as described above, the second sidewall portion  1463  of the lid section  1445  is fitted on the outside of the first sidewall portion  1453  of the storage section  1443  under the normal situation. However, when the both side surface of the second sidewall portion  1463  of the lid section  1445  are pressed, the second sidewall portion  1463  deflects by the pressing force, and thus the sidewall portion  1453  of the storage section  1443  and the sidewall portion  1463  of the lid section  1445  abut against each other when the storage section  1443  and the lid section  1445  are closed, thereby causing imperfect closing. Especially, in order to improve sealing performance of the storage case  1441 , the clearance between the first sidewall portion  1453  of the storage section  1443  and the second sidewall portion  1463  of the lid section  1445  have to be reduced as small as possible. However, when the clearance is reduced, a slight pressurizing movement causes abutment between the sidewall portions  1453  and  1463 , thereby causing imperfect closing. 
     In addition, depending on the extent of the pressing force, there may be a case where the second sidewall portion  1463  of the lid section  1445  comes inside the first sidewall portion  1453  of the storage section  1443 , which also causes imperfect closing. When it is stored in the badly closed state for a long time, the storage case is subjected to plastic deformation, which is not preferable. 
     With such a circumstance in view, it is the first object of the present invention to provide a magnetic tape cassette storage case in which imperfect closing can be prevented. 
     Various storage cases for magnetic tape cassettes are proposed depending on the configuration of the magnetic tape cassette to be stored. Referring to  FIG. 48  and  FIG. 49 , the storage case and the magnetic tape cassette of the related art will be described by way of example. 
     The storage case  1571  shown in  FIG. 48  and  FIG. 49  is formed integrally of synthetic resin. The storage case  1571  comprises a storage section  1573  for storing a magnetic tape cassette T, a lid section  1575 , and a connecting section  1577  for connecting the storage section  1573  and the lid section  1575  so as to enable the opening-closing motion. The storage section  1573  comprises a first plate portion  1581 , and a first sidewall portion  1583  formed integrally along the outer periphery thereof, and the lid section  1575  comprises a second plate portion  1585  and a second sidewall portion  1587  formed integrally along the outer periphery thereof. When the magnetic tape cassette T is appropriately stored in the storage case  1571 , the magnetic tape cassette T is fitted in the first sidewall portion  1583  in the state shown by a phantom line in  FIG. 49 . 
     On the outsides of the plate portions  1581 ,  1585 , and of the connecting section  1577 , there is formed an information sheet holding portion  1601 . The information sheet holding portion  1601  is used for storing information sheets  1603  such as a label or a memo on which data or the like relating the magnetic tape cassette T is listed. The information sheet holding portion  1601  is constructed in such a manner that recessed portions  1605  are formed in part on the respective outsides of the plate portions  1581 ,  1585  and of the connecting section  1577 , and almost the whole part of the recessed portions  1605  are covered by a transparent sheet  1607  of flexible synthetic resin. 
     The sheet  1607  is welded on the plate portions  1581 ,  1585  at both ends  1607   a ,  1607   b  of the recessed portion  1605 . Therefore, the information sheet  1603  may be inserted from the opened end of the sheet  1607  and held in the information sheet holding portion  1601 , in other words, between the sheet  1607  and the outsides of the plate portions  1581 ,  1585 , and the connecting section  1577 . 
     When the magnetic tape cassette T is stored in the storage case  1571 , the information sheet  1603  with data such as the recorded contents or the like is listed thereon is inserted into the information sheet holding portion  1601 . In this case, when the information sheet  1603  is small in size, it can be accommodated within the information sheet holding portion  1601 . However, when there are many recorded contents to be listed, the information sheet  1603  must be large in size as a matter of course, and thus it cannot be accommodated in the information sheet holding portion  1601  as shown in the figure. 
     The portion of the information sheet  1603  that cannot be accommodated is bent and deformed outward along the shoulder between the recessed portion  1605  and the plate portions  1581 ,  1585 . The portion of the information sheet  1603  that cannot be accommodated may be damaged or get soiled when the storage case  1571  is carried around. In addition, the same problem may arise when the storage cased  1571  stacked in layers are transported and when it is stored in the rack. 
     In contrast to it, when the information sheet  1603  is small, the problem of damage or dirt does not arise, but the information sheet  1603  may get hung up at the shoulder between the recessed portion  1605  and the plate portions  1581 ,  1585  when it is taken out from the information sheet holding portion  1601 , and thus there is the problem in that it is difficult to take the information sheet  1603 . 
     In addition, since the transparent sheet  1607  covers almost the entire surface of the recessed portion  1605 , the information sheets  1603  when the number of the information sheets increases, it will further be difficult to take the information sheet  1603  out. Therefore, the number of the information sheets  1605  to be held must be reduced, and thus the number of the information sheets that can be held is small. 
     With such a circumstance in view, it is the second object of the present invention to provide a magnetic tape cassette storage case in which the information sheets relating to the magnetic tape cassette can be kept without giving damage or dirt, in which the information sheets can easily be taken out, and in which many information sheets can be held. 
     Various types of storage cases for magnetic tape cassettes are proposed according to the configuration of the magnetic tape cassette to be stored. Referring now to  FIG. 50  to  FIG. 53 , the storage case and the magnetic tape cassette for DVCs of the related art will be described by way of example. 
     The storage case  1850  shown in  FIG. 50  comprises a storage section  1701  for storing the magnetic tape cassette  1881  shown in  FIG. 51 , a lid section  1702  for opening and closing with respect to the storage section  1701  as a book, and a connecting section  1703  for connecting the storage section  1701  and the lid section  1702 . The storage section  1701  comprises a first plate portion  1704 , a first sidewall portion  1705  formed integrally along the outer periphery of the first plate portion  1704  in the shape of a frame, reel locking ribs  1706   a ,  1706   b  formed on the first plate portion  1704  at the positions somewhat closer to the rear side than to the front side, and an opening locking rib  1707  formed on the first plate portion  1704  at the position somewhat closer to the front side in a V-shape in plan view. 
     The magnetic tape cassette  1881  shown in  FIG. 51  is stored in the storage section  1701 . When it is properly stored, it is loosely fitted in the first sidewall portion  1705  as shown in a phantom line in  FIG. 50 . 
     The lid section  1702  comprises a second plate portion  1708 , and a second sidewall portion  1709  formed integrally along three sides of the outer periphery of the second plate portion  1708 . The connecting section  1703  comprises the third plate portion  1810 . The third plate portion  1810  comprises thin portions  1810   a ,  1810   b  on both sides thereof. These thin portions  1810   a ,  1810   b  the storage section  1701  and the lid section  1702  to open and close as a book. When the storage case  1850  is closed, the first sidewall portion  1705  and the second sidewall portion  1709  are fitted in parallel with each other in such a manner that the second sidewall portion  1709  is fitted around the outside of the first sidewall portion  1705 . 
     Outside of the first sidewall portion  1705  that defines the storage section  1701 , there is provided a first overhanging portion  1704   a  that is formed by a part of the first plate portion  1704  in an overhanging manner. Therefore, even when the storage section  1701  and the lid section  1702  are closed, and the second sidewall portion  1709  of the lid section  1702  is fitted around the first sidewall portion  1705  of the storage section  1701 , the first overhanging portion  1704   a  prevents the storage section  1701  from getting into the lid section  1702 , and thus the thickness of the storage case may be maintained as a whole. 
     There are formed locking recesses  1705   a  in a trough shape on the outer wall surface on both sides of the first sidewall portion  1705  and a locking recess  1705   b  in a trough shape almost at the center of the outer wall surface on the rear side, and locking projections  1709   a  at the positions on the inner wall surface of the second sidewall portion  1709  corresponding to the locking recesses  1705   a  and a locking projection  1709   b  at the position corresponding to the locking recess  1705   b.    
     Therefore, when the storage section  1701  and the lid section  1702  are closed, the locking projection  1709   a  engages the locking recess  1705   a , and the locking projection  1709   b  engages the locking recess  1706   b  so as to prevent an accidental opening of the storage section  1701  and the lid section  1702 . 
     The first sidewall portion  1705  is formed with engaging recesses  1811   a ,  1811   b  on the first sidewall portion  1705 , and the second sidewall portion  1709  is formed with engaging recesses  1811   a ,  1811   b  and the same number of positioning ribs  1862   a ,  1862   b  on the inner wall surface thereof. When the storage case  1850  is closed, the engaging recesses  1811   a ,  1811   b  engage the positioning ribs  1862   a ,  1862   b  respectively. This engagement revents the first sidewall portion  1705  and the second sidewall portion  1709  from moving in parallel with each other. 
     When the storage case  1850  is closed, the positioning ribs  1862   a ,  1862   b  are inserted into the engaging recesses  1811   a ,  1811   b  respectively for positioning of the members. Therefore, engagement between the locking projections  1709   a ,  1709   b  and the locking recesses  1705   a ,  1706   b  is ensured, and thus the lid section  1702  can be positioned at the appropriate position. 
     A plurality of cassette holding members  1813  are formed on the side of the storage section between the inner surface of the first plate portion  1704  and the inner wall surface of the first sidewall section  1705 . In the same manner, a plurality of cassette holding members  1814  are formed on the side of the lid section between the inner surface of the second plate portion  1708  and the inner wall surface of the second sidewall portion  1709 . When the magnetic tape cassette  1881  is stored in the storage case  1850  by these cassette storage holding members  1813 ,  1814 , and the storage case  1850  is closed, the magnetic tape cassette  1881  will never come into direct contact with the first plate portion  1704  and the second plate portion  1708 , and the first sidewall portion  1705  and the second sidewall portion  1709  under normal conditions. 
     Referring now to  FIG. 51 , the magnetic tape cassette  1881  will be described.  FIG. 51  is a perspective view of the magnetic tape cassette  1881  viewed from the bottom side, and thus the upper cassette half  1883  is shown below the lower cassette half  1885 . 
     There are formed circular openings  1887   a ,  1887   b  at two locations on the lower cassette half  1885 , and engaging portions  1889   a ,  1889   b  integrally formed with the reel hubs (not shown) on which the magnetic tape is wound are exposed therefrom. The engaging portions  1889   a ,  1889   b  have a function to unwinding and winding the magnetic tape when it is mounted in the video tape recorder (VTR). 
     On the front side of the magnetic tape cassette  1881 , an outer lid  1891  is provided for pivotal movement, and when it is mounted in the VTR or the like, the magnetic tape is pulled out after the outer lid  1891  is pivoted as shown by the arrow A in  FIG. 51 . There is formed a recessed front opening  1893  inside the outer lid  1891  at near the center in such a manner that the upper and lower cassette halves  1883 ,  1885  are notched, and there is provided a shoulder  1895  on one end of the front opening  1893 . Both of them perform specific functions when the magnetic tape cassette  1881  is mounted in the VTR. 
     In order to mount the magnetic tape set  1881  in the storage case  1850 , the magnetic tape cassette  1881  is inserted in the first sidewall portion  1705  with the front opening  1893  faced downward, which is the position turned upside down from the position shown in  FIG. 51 , and with the front opening  1893  faced toward the opening locking rib  1707 . Consequently, the magnetic tape cassette  1881  is stored in the storage section  1701  as shown by phantom line in  FIG. 50 . Then, by overlaying the lid section  1702  on the storage section  1701  by the use of the connecting section  1703  as to close a book, the locking projections  1709   a ,  1709   b  engage the locking recesses  1705   a ,  1706   b  to close the storage section  1701  and the lid section  1702 , and thus the magnetic tape cassette  1881  is protected and prevented dust from entering therein. 
     The construction of the storage case  1850  and the magnetic tape cassette  1881  and the closing action thereof has been described so far. On the other hand, when the magnetic tape cassette  1881  is used, it is necessary to take the magnetic cassette  1881  from the storage case  1850  by releasing engagement between the locking projections  1709   a ,  1709   b  and the locking recesses  1705   a ,  1706   b . In order to take out the magnetic cassette, the storage section  1701  and the lid section  1702  are pulled in the opposite directions with fingers placed on one end of the storage case  1850  as shown by phantom lines in  FIG. 52  and  FIG. 53 . However, the storage case  1850  of the related art has a following problem. 
     In a state where the storage section  1701  and the lid section  1702  are closed, as shown in  FIG. 52 , a first overhanging portion  1704   a  projects from the end of the storage section  1701 , and a second overhanging portion  1708   a  projects from the end of the lid section  1702 . The person who tries to open the storage case  1850 , or the user, places his/her thumbs in about the center of the storage case  1850 , or in the vicinity of the position where the locking projection  1709   b  and the locking recess  1706   b  are engaged, and pulls them in the opposite directions with his/her thumbs hooked on the first and second overhanging portions  1704   a ,  1708   a  as shown in  FIG. 52  and  FIG. 53  by phantom lines. 
     When such a pulling operation is performed, the locking projection  1709   b  gets out of the locking recess  1706   b , and at almost the same time with it, the locking projection  1709   a  gets out of the locking recess  1705   a  and the storage case  1850  is opened. However, a force is required to release engagement between the locking projection  1709   b  and the locking recess  1706   b , and when a force is exerted by thumbs, apart of the second sidewall portion  1709  are pressed in the direction shown by an arrow a in  FIG. 52 . As a consequent, there is a problem in that the locking projection  1709   b  is pressed toward the locking recess  1706   b  and thus the storage case  1850  resists being opened on the contrary. 
     In order to solve this problem, a measure to eliminate the locking projection  1709   b  and the locking recess  1706   b  is conceivable. However, in such a construction, engagement between the storage section  1701  and the lid section  1702  becomes loose, which may result in another problems such as accidental opening of, and increase in possibility of entering of dust or the like into, the storage case  1850 . Since dust attached on the magnetic tape may cause a drop out of signals during recording and playing, it is necessary to lock the storage section  1701  and the lid section  1702  tightly. 
     With such a problem in view, the third object of the present invention is to provide a magnetic tape cassette storage case which is superior in hermeticity between the storage section and the lid section, and which is easy to open and close. 
     Various types of storage cases for magnetic tape cassettes are proposed depending on the configuration of the magnetic tape cassette to be stored. Referring now to  FIG. 54  to  FIG. 57 , a storage case and a magnetic tape cassette for DVCs of the related art will be described by way of example. 
     The storage case  2150  shown in  FIG. 54  comprises a storage section  1901  for storing the magnetic tape cassette  2081  shown in  FIG. 55 , a lid section  1902  for covering the storage section  1901 , and a connecting section  1903  for connecting the storage section  1901  and the lid section  1902 . The storage section  1901  comprises a first plate portion  1904 , a first sidewall portion  1905  formed integrally along the outer periphery of the first plate portion  1904 , reel engaging ribs  1906   a ,  1906   b  formed on the first plate portion  1904  at the positions somewhat closer to the rear side than to the front side, and a rib  1907  formed on the first plate  1904  at the position somewhat closer to the front side in a V-shape in cross section. When the magnetic tape cassette  2081  shown in  FIG. 55  is properly stored, it is loosely fitted in the first sidewall portion  1905  as shown by a phantom line in  FIG. 54 . 
     The lid section  1902  comprises a second plate portion  1908  and a second sidewall portion  1909  formed integrally along three sides of the outer periphery of the second plate portion  1908 . The connecting section  1903  comprises thin portions  2010   a ,  2010   b  formed on both sides of the third plate portion  2010 , which enables the storage section  1901  and the lid section  1902  to close as a book. When the storage case  2150  is closed, the second sidewall portion  1905  and the second sidewall portion  1909  are fitted in parallel with each other. 
     Outside of the first sidewall portion  1905  that defines the storage section  1901 , there is provided an overhanging portion  1904   a  that is formed by a part of the first plate portion  1904  in an overhanging manner. Therefore, even when the storage section  1901  and the lid section  1902  are closed, and the second sidewall portion  1909  of the lid section  1902  is fitted around the first sidewall portion  1905  of the storage section  1901 , the overhanging portion  1904 a prevents the storage section  1901  from getting into the lid section  1902 , and thus the thickness of the storage case may be maintained as a whole. The outer surface of the first sidewall portion  1905  is formed with a recessed locking portion  1905   a  and the inner side surface of the second sidewall portion  1909  is formed with a locking projection  1909   a  at the position corresponding to the locking portion  1905   a  when the storage section  1901  and the lid section  1902  are closed. Therefore, when the storage section  1901  and the lid section  1902  are closed, the locking projection  1909   a  engages the locking portion  1905   a  to prevent an accidental opening of the storage section  1901  and the lid section  1902 . 
     The first sidewall portion  1905  is formed with engaging recess  2011   a ,  2011   b , and the inner surface of the second sidewall portion  1909  is provided with the same number of positioning ribs  2062   a ,  2062   b  as the engaging recesses. When the case is closed, the engaging recess  2011   a  engages with the positioning rib  2062   a . In the same manner, the engaging recess  2011   b  engages with the positioning rib  2062   b . Such engagement prevents the first sidewall portion  1905  and the second sidewall portion  1909  from moving in parallel with each other. When the case is closed, the positioning ribs  2062   a ,  2062   b  are inserted into the engaging recesses  2011   a ,  2011   b  for positioning between members. Therefore, engagement between the locking projections  1909   a ,  1909   b  and the locking portions  1905   a ,  1905   b  is ensured, and thus the lid section  1902  can be positioned at the appropriate position. 
     A plurality of cassette holding members  2013  are formed on the side of the storage section between the inner surface of the first plate portion  1904  and the inner surface of the first sidewall portion  1905 . In the same manner, a plurality of cassette holding member  2014  are formed on the side of the lid section between the inner surface of the second plate portion  1908  and the inner surface of the second sidewall portion  1909 . When the magnetic tape cassette is stored in the storage case  2050  by these cassette holding members  2013  and  2014 , and the storage case  2050  is closed, the magnetic tape cassette will never come into direct contact with the first plate portion  1904  and the second plate portion  1908 , and the first sidewall portion  1905  and the second sidewall portion  1909  under normal conditions. 
     Referring now to  FIG. 55 , the magnetic tape cassette  2081  is described.  FIG. 55  is a perspective view of the magnetic tape cassette  2081  viewed from the bottom side, and thus the upper cassette half  2083  is shown below the lower cassette half  2085 . There are formed circular openings  2087   a ,  2087   b  at two locations on the lower cassette half  2085 , and engaging portions  2089   a ,  2089   b  integrally formed with the reel hubs (not shown) on which the magnetic tape is wound are exposed therefrom. The engaging portions  2089   a ,  2089   b  have a function to unwinding and winding the magnetic tape when it is mounted in the video tape recorder (VTR). 
     On the front side of the magnetic tape cassette  2081 , an outer lid  2091  is provided for pivotal movement, and when it is mounted in the VTR or the like, the magnetic tape is pulled out after the outer lid  2091  is pivoted as shown by the arrow A in  FIG. 55 . There is formed a recessed front opening  2093  inside the outer lid  2091  at near the center in such a manner that the upper and lower cassette halves  2083 ,  2085  are notched, and there is provided a shoulder  2095  on one end of the front opening  2093 . 
     In order to mount the magnetic tape cassette  2081  in the storage case  2150 , the magnetic tape cassette  2081  is inserted in the first sidewall portion  1905  with the front opening  2093  faced downward, which is the position turned upside down from the position shown in  FIG. 55 , and with the front opening  2093  faced toward the rib  1907 . 
     In such a storage case described above, when a instantaneous or continuous pressing force acts upon the second plate portion  1908  of the lid section  1902  in the vertical direction in the state that the storage case is closed, the following phenomenon is observed. 
     In a first place, a resilient deformation occurs on the second plate portion  1908 . The resilient deformation is, for example, a deformation shown by dashed lines in  FIG. 56 . As is apparent from  FIG. 56 , such deformation hinders parallel fitting between the second sidewall portion  1909  on the lid section  1902  and the first sidewall section  1905  on the storage section  1901 , thereby hindering engagement between the positioning ribs  2062   a ,  2062   b  and the engaging recesses  2011   a ,  2011   b  respectively. In other words, as a result of the resilient deformation, as shown in  FIG. 57 , the second sidewall portion  1909  and the positioning ribs  2062   a ,  2062   b  are shifted outwardly with respect to the storage case  2150  (in the direction shown by the arrow Dr in  FIG. 57 ) and deformed, so that imperfect engagement between the positioning ribs  2062   a ,  2062   b  and the engaging recesses  2011   a ,  2011   b  occurs. In addition, as a result of the pressing force and the imperfect engagement described above, a phenomenon that the lid section  1902  abnormally gets into the storage section  1901  occurs. The resilient deformation is obvious in the direction longitudinally of the storage case. When it is further pressed, deformation along the shorter dimension as well, thereby the entire storage case  2150  suffers from deformation. 
     In addition, when the deformed state of the storage case  2150  continues for a long time, each member is plastically deformed, and thus restoration to the normal state may become impossible. In other words, the entire storage case  2150  may be deformed permanently, and thus it may cause troubles in hermeticity, engaging performance, cassette storing capability of the storage case  2150  that used to be satisfactory. 
     With such a circumstance in view, it is the fourth object of the present invention to provide a storage case in which a shift or deformation of the sidewall portion resulting from resilient deformation of the members may be prevented. 
     Various types of storage cases for magnetic tape cassettes are proposed depending on the configuration of the magnetic tape cassette to be stored. Referring now to  FIG. 58  and  FIG. 59 , the storage case and the DVC used in the broadcasting station of the related art will be described by way of example. 
     The storage case  2350  shown in  FIG. 58  comprises a storage section  2201  for storing the magnetic tape cassette  2381  shown in  FIG. 59 , the lid section  2202  for covering the storage section  2201 , and a connecting section  2203  for connecting the storage section  2201  and the lid section  2202  for pivotal movement. The storage section  2201  comprises a first plate portion  2204 , a first sidewall portion  2205  formed integrally along the outer periphery of the first plate portion  2204 , reel locking ribs  2206   a ,  2206   b  formed on the first plate portion  2204  at the positions somewhat closer to the rear side than to the front side, and a opening locking rib  2207  formed on the first plate  2204  at the position a bit close to the front side in a V-shape in cross section. When the magnetic tape cassette  2381  shown in  FIG. 59  is properly stored, it is fitted in the first sidewall portion  2205  as shown by a phantom lien in  FIG. 58 . 
     The lid section  2202  comprises a second plate portion  2208  and a second sidewall portion  2209  formed integrally along three sides of the outer periphery of the second plate portion  2208 . The connecting section  2203  comprises thin portions  2310   a ,  2310   b  formed on both sides of the third plate portion  2010 , which enables the storage section  2201  and the lid section  2202  to close as a book. When the storage case  2350  is closed, the first sidewall portion  2205  and the second sidewall portion  2209  are fitted in parallel with each other. 
     Outside of the first sidewall portion  2205  that defines the storage section  2201 , there is provided an overhanging portion  2204   a  that is formed by a part of the first plate portion  2204  in an overhanging manner. Therefore, even when the storage section  2201  and the lid section  2202  are closed, and the second sidewall portion  2209  of the lid section  2202  is fitted around the first sidewall portion  2205  of the storage section  2201 , the overhanging portion  2204   a  prevents the storage section  2201  from getting into the lid section  2202 , and thus the thickness of the storage case may be maintained as a whole. 
     The outer surface of the first sidewall portion  2205  is formed with a recessed locking portion  2205   a  and the inner side surface of the second sidewall portion  2209  is formed with a locking projection  2209   a  at the position corresponding to the locking portion  2205   a  when the storage section  2201  and the lid section  2202  are closed. Therefore, when the storage section  2201  and the lid section  2202  are closed, the locking projection  2209   a  engages the locking portion  2205   a  to prevent an accidental opening of the storage section  2201  and the lid section  2202 . 
     The first sidewall portion  2205  is formed with an engaging recess  2311   a ,  2311   b , and the inner surface of the second sidewall portion  2209  is provided with the same number of positioning ribs  2362   a ,  2362   b  as the engaging recesses. When the storage case is closed, the engaging recesses  2311   a ,  2311   b  engage with the positioning ribs  2362   a ,  2362   b . Such engagement prevents the first sidewall portion  2205  and the second sidewall portion  2209  from moving in parallel with each other. When the storage case is closed, the positioning ribs  2362   a ,  2362   b  are inserted into the engaging recesses  2311   a ,  2311   b  for positioning between members. Therefore, engagement between the locking projections  2209   a ,  2209   b  and the locking portions  2205   a ,  2205   b  is ensured, and thus the lid section  2202  can be positioned at the appropriate position. 
     A plurality of cassette holding members  2313  are formed on the side of the storage section between the inner surface of the first plate portion  2204  and the inner surface of the first sidewall portion  2205 . In the same manner, a plurality of cassette holding member  2314  are formed on the side of the lid section between the inner surface of the second plate portion  2208  and the inner surface of the second sidewall portion  2209 . 
     Referring now to  FIG. 59 , the magnetic tape cassette  2381  is described.  FIG. 59  is a perspective view of the magnetic tape cassette  2381  viewed from the bottom side, and thus the upper cassette half  2383  is shown below the lower cassette half  2385 . There are formed circular openings  2387   a ,  2387   b  at two locations on the lower cassette half  2385 , and reference rings  2389   a ,  2389   b  that is a dimension standard formed on the lower reel of the tape reels with the magnetic tape wound thereon. 
     On the front side of the magnetic tape cassette  2381 , an outer lid  2391 , an top lid  2397 , and an inner lid (not shown) are provided for pivotal movement, and when it is mounted in the VTR or the like, the magnetic tape is pulled out after the outer lid  2391  is pivoted as shown by the arrow A in  FIG. 59 . There is formed a recessed front opening  2393  inside the outer lid  2391  at near the center in such a manner that the upper and lower cassette halves  2383 ,  2385  are notched, and there is provided a shoulder  2395 , which is a recessed portion having generally the shape of a section at one end of the front opening  2393 . The shoulder  2395  is formed at the rear of the cassette with respect to the top lid  2397 . 
     In order to mount the magnetic tape cassette  2381  in the storage case  2350 , the magnetic tape cassette  2381  is fitted within the sidewall portion  2205  as shown in  FIG. 58  by a phantom line in such a manner that the front opening  93  is faced toward the opening locking rib  2207 , and the reel locking ribs  2206   a ,  2206   b  are pushed to be inserted within the circular engaging holes B formed at the centers of the hubs of the tape reels, whereby the magnetic tape cassette  2381  is stored in the storage case  2350 . 
     However, in the structure of the storage case  2350  described above, the following problem was recognized when the magnetic tape cassette  2381  is stored. As shown in  FIG. 60 , in the case where the magnetic tape cassette  2381  is inserted upside down, the top lid  2397  may be compressed by the opening locking portion  2207   a  of the opening locking rib  2207 . When the top lid  2397  is compressed, the top lid  2397 , and thus the outer lid  2391  and the inner lid (not shown) connected to the top lid may be deformed. When it is compressed with a force, these lids may be damaged. Since these lid serves to cover the magnetic tape for protection, deformation of these lids may give damage to the magnetic tape. 
     As shown in  FIG. 61 , even in a state in which the magnetic tape cassette  2381  is properly inserted, the tape reel  2410  may be displaced in case of drop in such a state. Then, the reel locking ribs  2206   a ,  2206   b  come into collision with the engaging hole B formed on the hub  2415  of the tape reel  2410 , and thus the reel locking ribs  2206   a ,  2206   b  are subjected to an excessive load. When such an excessive load is applied repeatedly, there may be a case where the reel locking rib may be broken. 
     With such a circumstance in view, the fifth object of the present invention is to provide a storage case in which deformation that may be occurred when it is subjected to an impact in case of a drop can be prevented as well as, deformation of the lid can be prevented even when the magnetic tape cassette is inserted in a wrong way. 
     Recent years, a compact digital video camera of good portability came into wide use as a TV camera exclusively used for recording coverage. This type of camera is compact in size, but high-quality pictures can be obtained by processing digital signal. Therefore, it is widely used as equipment for business use among cameramen for broadcasting station or specialists for recording coverage. 
     The DVC to be used in the portable digital video camera come in three sizes being different in recording time period, and sold in the dedicated cassette storage case. 
     The magnetic tape cassette such as the DVC or the like described above are in many cases used for recording covered scenes, or brought to the broadcasting station as a material for editing/rerecording, and thus contains important pictures or scenes recorded therein. Therefore, it is preferable to store the recorded contents or the details to be consulted at the worksite together with the magnetic tape cassette. By organizing in this way, information on the recorded contents of the magnetic tape cassette or other related information, for example, on the site or the like can be checked out easily with the recorded contents later at the meeting. 
     Generally, this type of information in association with the recorded contents are shown by adhering a label on the magnetic tape cassette and the storage case, or by inserting a sheet of paper or information sheets such as a leaflet on which the recorded contents are listed in a space in the storage case. However, since the thickness of the space in the storage case is only as small as the thickness of the magnetic tape cassette, the amount of information sheets that can be stored with the magnetic tape cassette is small. 
     Accordingly, in Japanese Patent Application No. 230835/1998, the applicant of the present invention proposes a magnetic tape cassette storage case in which a storage section for storing the magnetic tape cassette, a lid section having a peripheral wall surrounding the storage section, and a connecting section for connecting the storage section and the lid section so as to be able to close and open are integrally formed of synthetic resin, and holding ribs are formed on the inner surface of the peripheral wall of the lid section on both sides for holding the magnetic tape cassette between itself and the bottom wall of the storage section by coming into contact with the peripheral edge on the surface of the magnetic tape cassette when the magnetic tape cassette is stored, and a sheet-holding rib is formed on at least one of holding ribs for holding one end of the information sheet between itself and the top plate, or the second plate portion of the lid section. 
     According to this magnetic tape cassette storage case, the information sheet can be stored in the storage case without jumping out, dropping off, or overhanging by clamping the end of the information sheet between the sheet-holding rib and the top plate when the information sheet is stored. 
     When such a magnetic tape cassette storage case is formed by injection molding, the holding rib with an undercut portion is molded by a slide core or a rocking core. 
     However, the direction of cutting or rocking of the core is the direction toward the center of the metal mold (inward of the metal mold), the core have to enter into the metal mold significantly toward the center thereof. In addition, when the overhanging amount of the undercut portion of the holding rib in association with the sheet-holding rib is significant, the line formed at the junction between the core and the metal mold extends to the center of the top plate of the lid of the magnetic tape cassette storage case. Therefore, for the storage case for transparent magnetic tape cassette, the appearance and the interior visibility may be spoiled. 
     Accordingly, the present invention is directed to solve the problem described above, and thus it is the sixth object to provide a less expensive metal mold for magnetic tape cassette storage cases and a magnetic tape cassette storage case with preferable appearance and interior visibility. 
     There are various types of magnetic tape cassettes, and the one used in the digital video camera described above is called DVC. 
     A magnetic tape cassette storage case used in the related art (storage case for DVCs) is shown in  FIG. 62  by way of example. The storage case  2580  comprises a storage section  2581  for storing the magnetic tape cassette M, and a lid section  2591  connected to the storage section  2581  via a connecting section including the plate portion  2590  and the thin portion  2589 . The storage section  2581  comprises a bottom plate  2582 , or a first plate portion, having a plurality of mounting projections  2587 ,  2588  on the inner surface (upper surface in the figure) according to the recessed shape of the magnetic tape cassette M, and sidewalls  2583 ,  2583  and an end wall  2584 , or a first sidewall portion, standing along the periphery of the bottom plate  2582  for fitting the magnetic tape cassette A. The upper end and the outer surface of the sidewall  2583  are formed with a positioning notch  2585  and a locking recess  2586  respectively for engaging the lid section  2591 . 
     The lid section  2591  comprises a top plate  2592 , or a second plate portion, and sidewalls  2593 ,  2593 , and an end wall  2594 , or the second sidewall portion, standing on the inner surface, or the surface opposing to the storage section  2581  of the top plate  2592  for fitting around the sidewall  2583  and the end wall  2584  of the storage section  2581 . The inner surface of the sidewall  2593  is formed with a positioning rib  2595  and a locking claw  2596  for engaging the positioning notch  2585  and the locking recess  2586  of the storage section  2581  respectively. The inner surface of the sidewall  2593  is formed with a supporting rib  2597  having a bevel  2597   a . The supporting rib  2597  supports the magnetic tape cassette M by the bevel  2597   a  when the magnetic tape cassette M is stored in the storage section  2581  and the lid section  2591  is closed. 
     The positioning rib  2595  and the supporting rib  2597  are in contact with the top plate  2592  at one end, and extend along the sidewall  2693 . In contrast to it, the locking claw  2596  is provided near the distal end of the sidewall  2593  and is not in contact with the top plate  2592 . 
     The storage case  2580  is molded by injection molding or the like. The metal mold comprises a main body of the metal mold, or the movable die for molding the inner side of the storage case  2580 , and a fixed die for molding outside of the storage case  2580 . The metal mold comprises a cavity for undercut portion on its side surface for molding a undercut portion such as a locking claw  2596  or the like, an ejector pin that inclines while ejecting the molded article out from the movable die by its tip surface (hereinafter referred to as “inclining pin”), and a slide core. While the inclining pin is inclining, the undercut portion is ejected from the cavity on the side surface of the inclining pin. 
     In the magnetic tape cassette storage case  2580  or the magnetic tape cassette storage case similar to the case  2580  of which the heights of the sidewall  2593  and the end wall  2594  of the lid section  2591  are in excess of a prescribed value, mold breathing tends to be worsened. This tendency is obvious especially for the storage case for the magnetic tape cassettes of which the heights of the sidewall  249  and the end wall  2594  of the lid section  2591  are not less than 6 mm, though it depends on the width of the gas bent or the position where the gas bent is disposed. Even when the heights of the sidewall  93  and the end wall  94  are less than 6 mm, imperfect mold breathing occurred. 
     When mold breathing is insufficient, bubbles are trapped in the sidewall  2593  of the storage case, which spoils the appearance of the transparent magnetic tape cassette storage case formed especially of polypropylene or the like. 
     With such a problem in view, it is the seventh object of the present invention to provide a metal mold for the storage cases for magnetic tape cassettes with good breathing, and a magnetic tape cassette storage case of good appearance that can be molded by the metal mold described above. 
     DISCLOSURE OF THE INVENTION 
     The first object of the present invention is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing a magnetic tape cassette; 
     a lid section for covering the storage section; and 
     a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; 
     the storage section and the lid section each including a plate portion and a sidewall portion provided along the outer periphery of the plate portion; 
     the sidewall portion of the lid section being fitted along the outside of the sidewall portion of the storage section so that an locking portion formed inside of the sidewall portion of the lid section engages an locked portion formed on the outside of the sidewall portion of the storage section when the storage section and the lid section are closed; 
     characterized in that a notch having at least the same height as the sidewall portion of the storage section is formed on the inner side of the sidewall portion of the lid section at the end near the connecting section. 
     In the storage case of the structure described above, even when the sidewall portion of the lid section is subjected to a pressurizing force and thus deflected, the notch formed on the inner end of the sidewall portion of the lid section at the end near the connecting section abuts against the sidewall portion of the storage section to allow the sidewall portion of the lid section to be fitted on the outside of the sidewall portion of the storage section when the storage section and the lid section are closed. 
     Therefore, the notch can prevent imperfect closing of the storage case. 
     Here, the notch is preferably a bevel of a flat surface. 
     The second object of the present invention is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing a magnetic tape cassette; a lid section for covering the storage section; and a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion formed integrally of synthetic resin; characterized in that a rib is provided along the periphery of the outside surface of at least one of the storage section and the lid section; in that the outside surface surrounded by the rib is formed into a flat portion; and in that an information sheet holding portion is provided by welding opposite sides of a transparent sheet on the outside surface so as to cover a part of the flat portion. 
     The storage case is provided with a rib along the periphery of the outside surface of at least one of the storage section for storing the magnetic tape cassette and the lid section, and the portion surrounded by the rib is formed into a flat portion and a part of the flat portion is covered by the transparent sheet to form a information sheet holding portion. 
     Therefore, the information sheet on which the recorded contents or the like relating to the magnetic tape cassette may be held between the flat portion and the transparent sheet, in other words, in the information sheet holding portion. In addition, since the information sheet held therein runs along the flat portion, deformation can be prevented, and the number of the information sheets to be held can be increased according to the height of the rib. 
     In the present invention, covering a part of the flat portion by the transparent sheet means that a part that is not covered by the transparent sheet exists to the extent that the information sheet is not hindered from being taken out. 
     The rib to be provided along the periphery of the plate portion may not be provided all around the periphery as far as it can prevent the sheet from coming into contact with the surface on which the storage case is placed when it is placed thereon. The rib may be provided respectively along the three sides of the plate portion, or along the two opposite sides of the plate portion all the way or in part. 
     The third object of the present invention is achieved by providing a magnetic tape cassettes storage case comprising: 
     a storage section for storing a magnetic tape cassette; 
     a lid section for covering the storage section; 
     a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; 
     the storage section including a first plate portion, a first sidewall portion provided along the outer periphery of the first plate portion, a locking recess provided on the outer wall surface of the first sidewall portion, and a first overhanging portion overhanging outwardly from the first sidewall portion; 
     the lid section including a second plate portion, a second sidewall portion provided along the outer periphery of the second plate portion, a locking projection provided on the inner wall surface of the second sidewall portion, and a second overhanging portion overhanging outwardly from the second sidewall portion; and 
     the second sidewall portion being fitted along the outside of the first sidewall portion so that the locking recess and the locking projection are engaged when the lid section is covered on the storage section; 
     characterized in that a part of the second sidewall portion, and at least the portion on which the locking projection is provided is formed to be flush with the first overhanging portion and the second overhanging portion. 
     According to the magnetic tape cassette storage case of the structure described above, when the storage case is closed by covering the lid section on the storage section, the locking projection on the second sidewall portion provided along the outer periphery of the second plate portion engages the locking recess on the first sidewall portion provided along the outer periphery of the first plate portion. 
     Though the end portions of the first and second plate portion project as a first and second overhanging portion on the closed surface, the portion of the second sidewall portion on which the locking projection is provided is formed as a thick portion, and thus the portion where the locking projection and the locking recess engage is flush with the first and second overhanging portion. 
     Therefore, since the fingers are not placed on the thick portion to open the storage case and the thick portion resists deformation of the second wall portion, the storage case can easily be opened. 
     It is also possible to provide a locking projection at the end of the second sidewall portion where the thick portion is provided, and to provide a locking recess at the end of the first plate portion at the location corresponding to the locking projection when the lid section is covered on the storage section. 
     In this arrangement, the portion where the locking projection is provided is formed into a thick portion, and the locking projection provided on the second sidewall portion engages at an end of the first plate portion, in other words the locking recess provided on the overhanging portion. Therefore, when the storage case is opened, engagement between the locking projection and the locking recess prevents deflected deformation of the second sidewall portion, and thus the multiplier effect with the thick portion enables easier opening of the storage case. 
     Alternatively, it is also possible to provide a plurality of locking projection in the vicinity of the end portion of the second wall portion, or of the portion where the thick portion is provided, and to provide a locking recess at one end of the first plate portion at the location corresponding to the plurality of locking projection when the storage section is covered by the lid section. 
     In this arrangement, the portion where the locking projection is provided is formed into a thick portion and a plurality of locking projection provided on the second sidewall portion engage one end of the first plate portion, in other word, a plurality of locking recesses provided on the overhanging portion. Therefore, even when a force is applied to the second sidewall portion by the fingers to open the storage case, engagement between a plurality of locking projection and the locking recess prevents deflected deformation of the second sidewall portion, and thus the multiplier effect with the thick portion enables easier opening of the storage case. 
     The third object of the present invention is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing a magnetic tape cassette; 
     a lid section for covering the storage section; 
     a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; 
     the storage section including a first plate portion, a first sidewall portion provided along the outer periphery of the first plate portion, a locking recess provided on the outer wall surface of the first sidewall portion, and a first overhanging portion overhanging outwardly from the first sidewall portion; 
     the lid section including a second plate portion, a second sidewall portion provided along the outer periphery of the second plate portion, a locking projection provided on the inner wall surface of the second sidewall portion, and a second overhanging portion overhanging outwardly from the second sidewall portion; and 
     the second sidewall portion being fitted along the outside of the first sidewall portion so that the locking recess and the locking projection are engaged when the lid section is covered on the storage section; 
     characterized in that a part of the first overhanging portion and the second overhanging portion and at least the portion on which the locking recess and the locking projection are provided is formed to be flush with the sidewall portion. 
     According to the magnetic tape cassette storage case in the arrangement described above, when the storage case is close by covering the lid section on the storage section, the locking projection of the second sidewall portion provided along the outer periphery of the second plate portion engages the locking recess of the first sidewall portion provided along the outer periphery of the first plate portion. 
     Though the end portions of the first and second plate portions project from the closed surface as a first and second overhanging portions, the portion on which the locking recess on the first sidewall portion and the locking projection of the second sidewall portion are notched. Therefore, the first and second overhanging portions are eliminated at the portion where the locking projection and the locking recess are engaged, and thus they are flush with each other. 
     Therefore, since the fingers are not placed on the notched portion to open the storage case, the storage case can easily be opened. 
     The third object of the present invention is achieved by providing a storage case for magnetic tape cassettes comprising: 
     a storage section for storing a magnetic tape cassette; 
     a lid section for covering the storage section; 
     a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; 
     the storage section including a first plate portion, a first sidewall portion provided along the outer periphery of the first plate portion, a locking projection provided on the outer periphery of the first plate portion and protecting inwardly, and a first overhanging portion overhung outwardly from the first sidewall portion; 
     the lid section including a second plate portion, a second sidewall portion provided along the outer periphery of the second plate portion, a locking recess provided on the outer wall surface of the second sidewall portion, and a second overhanging portion projecting from the second sidewall portion toward the outer periphery; 
     characterized in that the second sidewall portion is fitted around the outside of the first sidewall portion and the locking projection and the locking recess engages when the lid section is covered on the storage section. 
     According to the magnetic tape cassette storage case of the structure described above, when the storage case is closed by covering the lid section on the storage section, the locking recess provided on the outer wall surface of the second sidewall portion engages the locking projection provided on the outer periphery of the first plate portion and projecting inwardly. 
     Therefore, when the second sidewall portion is pressurized to open the storage case, the locking projection and the locking recess do not engage, and thus the storage case can easily be opened. 
     The fourth object of the present invention is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing a magnetic tape cassette; 
     a lid section for covering the storage section; 
     connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; 
     the storage section including a first plate portion and a first sidewall portion provided along the outer periphery of the first plate portion; 
     the lid section including a second plate portion and a second sidewall portion provided along the outer periphery of the second plate portion; 
     the second sidewall portion being provided with at least one positioning rib on the inner surface thereof; and 
     the second sidewall portion being provided with an engaging recess for engaging with the positioning rib when the lid section is covered on the storage section; 
     characterized in that the positioning rib includes a fitting portion formed inwardly with respect to the lid section and being longer than the longitudinal length of the positioning rib, so that the fitting portion abuts against the first sidewall portion when the lid section is covered on the storage section. 
     According to this arrangement of the present invention, even when a force is applied to the second plate portion and causes a resilient deformation when the case is in the closed state, since the positioning rib, and thus the fitting portion being integral with the second sidewall portion, abuts against the inner surface of the first sidewall portion, the positioning rib will not be shifted or deformed outwardly of the first sidewall portion. 
     Therefore, shift or deformation of the second sidewall portion will not be generated. In addition, the lid section is prevented from digging into the storage section. 
     In the storage case described above, it is needless to say that various types of locking mechanisms for preventing accidental opening of the storage section and the lid section can be employed, and specifically, a construction in which locking is made on the sidewall portion that opposes to the connecting section in parallel when the lid is closed is also included. 
     The fourth object is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing the magnetic tape cassette; 
     a lid section for covering the storage section; 
     a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; 
     the storage section including a first plate portion and a first sidewall portion provided along the outer periphery of the first plate portion; 
     the lid section including a second plate portion and a second sidewall portion provided along the outer periphery of the second sidewall portion; and 
     the first sidewall portion including an overhanging portion overhanging outwardly from the first sidewall portion; 
     characterized in that a fitting groove in which the edge of the second sidewall portion is fitted is formed on the overhanging portion. 
     In the structure of the present invention described above, even when a force is applied to the second plate portion and causes a resilient deformation when the case is in the closed state, since the edge of the second wall portion and the fitting groove are fitted, the fitted portion serves as an element to prevent the outward movement. Therefore, the second wall portion resists deformation, and thus the second wall portion will not be shifted outwardly with respect to the entire case. 
     As a consequent, the lid section can be prevented from digging into the storage section. This characteristic brings about the same effect when a pressurizing force is applied to the first plate portion. 
     In this storage case, it is needless to say that various types of locking mechanisms can be employed, and specifically, a construction in which locking is made on the sidewall portion that opposes to the connecting section in parallel when the lid is closed in also included. 
     Providing the locking mechanism on the sidewall portion that opposes to the connecting section in parallel when the lid is closed can prevent the storage case from irregular opening. Preventing irregular opening can prevent the first sidewall portion and the second sidewall portion from accidental resilient deformation, and thus shift or deformation of the sidewall portion of the storage case caused by the resilient deformation may be prevented. 
     According to the present invention, the magnetic tape cassette storage case having the characteristics described above is proposed. It is needless to say that this magnetic tape cassette storage case has both of the advantages described above. 
     The fifth object of the present invention is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing the magnetic tape cassette; 
     a lid section for covering the storage section; 
     a connecting section for connecting the storage section and the lid section so as to enable the opening-closing motion; and 
     the storage section including a plate portion and a sidewall portion provided along the outer periphery of the plate portion; 
     characterized in that the plate portion is formed with a reel locking rib for engaging the engaging hole on the hub of the tape reel and a recess locking rib for engaging the recess formed at the rear of the cassette with respect to the lid of the lower cassette half; 
     in that the recess locking rib is set to the height lower than the height of the reel locking rib; 
     in that where the distance between the reference ring of the lower reel constituting the tape reel and the circular opening that corresponds to the outer periphery of the reference ring and formed on the lower cassette half is b, and the distance between the engaging hole of the hub and the reel locking rib is a, the relation is a&gt;b;
         in that the distance c from the both side surfaces of the cassette and the rear surface of the cassette to the sidewall portion of the storage section facing to these respective surfaces and the distance c between the recess and the recess locking rib are set to the same value.       

     According to the structure of the present invention described above, since the recess locking rib that engages the recess of the lower cassette half when the cassette is properly inserted is formed at the rear of the cassette with respect to the lid, even when the cassette is inserted upside down by mistake, it does not abut against the lid that covers the magnetic tape. 
     Therefore, since the lid and the recess locking rib do not abut against each other even when the user inserted the cassette into the storage section of the storage case in a wrong way, deformation and damage of the lid can be prevented and thus the magnetic tape is protected. 
     The height of the recess locking rib is set to the height lower than the reel locking rib for locking the hub of the reel on which the magnetic tape is wound. 
     Therefore, since the height of the recess locking rib  15  not that high, even when the user inserted the cassette into the storage section of the storage case in the proper orientation but in the state of being shifted from the proper position in the direction B by mistake, deformation and damage of the lid (inner lid) is prevented. In addition, even when the cassette is inserted into the storage section of the storage case upside down and in the state of being shifted in the fro-and-aft direction from the proper position, deformation and damage of the lid (top lid) is prevented. 
     The distance b between the reference ring of the lower reel and a circular opening formed on the lower cassette half is set to the smaller value than the distance a between the engaging hole of the hub and the reel engaging rib. 
     Therefore, even when the storage case with the cassette stored drops, the reel reference ring comes into collision with the wall of the circular opening of the lower cassette half in the first place to absorb the impact, whereby excessive load is not applied to the reel locking rib. 
     Since the distance c from the both side surface of the cassette and the rear surface of the cassette to the sidewall portion of the storage section opposing to these surfaces, and the distance c between the recess and the recess locking rib are the same value, the clearance where the storage case and the cassette come into contact is uniform. 
     Therefore, since a load applied under vibration is uniform, the occurrence of scratches or powder due to rubbing between the storage case and the cassette can be dispersed. 
     The sixth object of the present invention is achieved by a metal mold for magnetic tape cassette storage cases comprising: 
     a storage section for storing a magnetic tape cassette, 
     a lid section including a peripheral wall surrounding the storage section, 
     a connecting section for connecting the storing section and the lid section so as to enable opening-and-closing motion integrally formed of synthetic resin, 
     at least one holding rib that abuts the peripheral edge of the surface of the magnetic tape cassette when the magnetic tape cassette is stored for holding the magnetic tape cassette between itself and the plate portion of the storage section being formed on the inner surface of the peripheral wall of the lid section, and 
     an overhanging sheet holding rib extending inwardly of the peripheral wall for holding the sheet end of the information sheet between itself and the plate portion of the lid section being formed on at least one of the holding ribs, 
     characterized in that a rib-molding core for forming the holding rib accompanied by a sheet holding rib is provided on the movable die for forming the inner side of the magnetic tape cassette storage case so as to be able to project therefrom, and to pivot in the direction along the peripheral wall when it is projected from the movable die. 
     According to the metal mold for magnetic tape cassette storage case of the present invention, since the direction of the pivotal movement of the rib-molding core when it is projected from the movable core runs along the peripheral wall of the magnetic tape cassette storage case, the line formed at the junction between the rib-molding core and the meal mold is formed along the sidewall of the magnetic tape cassette storage case. Therefore, the line at the junction between the rib-molding core and the metal mold extending to the center of the magnetic tape cassette storage case is not formed, thereby preventing the appearance and the interior visibility from being spoiled. 
     Since the sheet holding rib is generally thin for the extent of projection, the extent of overhang of the under cut is small, and thus the extent of pivotal movement of the rib-molding core may be small and the metal mold may be manufactured at low cost. 
     The rib-molding core according to the present invention may be a core specially constructed for molding the holding rib accompanied by a sheet holding rib, or it may also serve as a pushing pin for releasing the molded article from the metal mold. In the latter case, the molding surface for molding the holding rib is formed on the side surface of the distal end of the pushing pin. 
     The sixth object of the present invention is achieved by providing a magnetic tape cassette storage case comprising: 
     a storage section for storing a magnetic tape cassette; 
     a lid section having a peripheral wall surrounding the storage section; 
     a connecting section for connecting the storage section and the lid section so as to enable the open-and-close motion integrally molded of synthetic resin; 
     at least one holding rib that abuts the peripheral edge of the surface of the magnetic tape cassette when the magnetic tape cassette is stored for holding the magnetic tape cassette between itself and the plate portion of the storage section being formed on the inner surface of the peripheral wall of the lid section, and 
     an overhanging sheet holding rib extending inwardly of the peripheral wall for holding the sheet end of the information sheet between itself and the plate portion of the lid section being formed on at least one of the holding ribs, 
     characterized in that the holding rib accompanied by the sheet holding rib is formed with a seat at the proximal end on the side of the plate portion of the lid section and with a back holder at the proximal end on the peripheral wall side. 
     According to the magnetic tape cassette storage case of the present invention, by making the configuration of the seat and rib-molding core in agreement, the line formed by the junction between the rib-molding core and the metal mold can be eliminated, and thus the appearance and the interior visibility are not spoiled. In addition, since the rib-molding core does not come into contact with the molded lid section of the magnetic tape cassette storage case when it accomplishes a pivotal movement, there is no chance to scratch the lid section of the magnetic tape cassette storage case. By providing a back holder on the holding rib, when the rib-molding core accomplishes a pivotal movement, not only the end surface of the rib-molding core, but also the side surface thereof immediately move away from the peripheral wall of the molded magnetic tape cassette storage case, and thus the peripheral wall of the magnetic tape cassette storage case is not scratched. 
     The seventh object of the present invention is achieved by providing a metal mold for molding magnetic tape cassette storage cases constructed by the combination of a first case and a second case each having a plate and a peripheral wall, in which the peripheral wall of at least one of the first case and the second case includes a wall of 6 mm or more in height, 
     characterized in that the wall having a rib being in contact with the plate and extending along the wall from among the walls described above is formed in part by the ejector pin that pushes the case out from the main body of the metal mold by the distal end surface while passing through the main body of the metal mold having a cavity for the rib on its side surface for molding the inside of the case, and the wall that does not have a rib from among the walls described above is formed in part by the ejector pin for pushing the case out from the main body of the metal mold by the distal end surface passing through the main body of the metal mold for molding the inside of the case. 
     In other words, in the metal mold for magnetic tape cassette storage case of the present invention, the wall having a rib being in contact with the top plate and extending along the peripheral wall, such as a positioning rib or a supporting rib on the lid section from among the sidewalls and the end wall of at least 6 mm in height constituting the peripheral wall is formed in part by the ejector pin having a cavity for the rib on the side surface for pushing the case, or the molded article, by the distal end surface. The wall that does not have the rib from between the sidewalls and the end wall of at least 6 mm in height is molded by the ejector pin in part. 
     When the sidewalls and the end wall constituting the peripheral wall do not have the rib, a part of each wall is formed by the ejector pin. At this time, the ejector pin is preferably disposed in the cavity near the location where resin is filled at last, which can make breathing smoother. 
     As an ejector pin, a inclining pin or an ejector pin that pushes the molded article out in the direction parallel to the movement of the main body of the movable metal mold may be employed. The clearance between the main body of the metal mold and the ejector pin that passes through the main body of the metal mold at the time of molding is preferably 0.01–0.03 mm. If the clearance is below 0.01 mm, pushing-out operation cannot be made smoothly, and if it exceeds 0.03 mm, bur or the like will be generated. 
     According to the metal mold for magnetic tape cassette storage case in this arrangement, breathing can be performed reliably in the case of molding the magnetic tape cassette storage case having a peripheral wall of at least 6 mm in height, thereby preventing babbles from being trapped in the sidewalls or the like of the storage case. Therefore, the magnetic tape cassette storage case with a good appearance may be obtained. 
     The seventh object of the present invention is achieved by providing a magnetic tape cassette storage case constructed by the combination of a first case and a second case each having a plate and a peripheral wall, in which the peripheral wall of at least one of the first case and the second case includes a wall of 6 mm or more in height; 
     characterized in that the wall having a rib being in contact with the plate and extending along the wall from among the walls described above is formed in part by the ejector pin that pushes the case out from the main body of the metal mold by the distal end surface while passing through the metal mold body having a cavity for the rib on its side surface for molding the inside of the case, and the wall that does not have a rib from among the walls described above is formed in part by the ejector pin for pushing the case out from the main body of the metal mold by the distal end surface passing through the main body of the metal mold for molding the inside of the case. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a magnetic tape cassette storage case according to the first embodiment of the present invention. 
         FIG. 2  is a partially enlarged plan view of  FIG. 1 . 
         FIG. 3  is a perspective view showing a magnetic tape cassette storage case according to the second embodiment of the present invention. 
         FIG. 4  is a perspective view showing the structure of the information sheet holding portion. 
         FIG. 5  is a cross-sectional view taken along the line A—A of  FIG. 4 . 
         FIG. 6  is a perspective view showing an example of the magnetic tape cassettes. 
         FIG. 7  is a perspective view showing the structure of the magnetic tape cassette storage case according to the third embodiment of the present invention in the opened state. 
         FIG. 8  is a perspective view showing the structure of the magnetic tape cassette storage case in the closed state. 
         FIG. 9  is a cross-sectional view showing the structure and the action of the thick portion. 
         FIG. 10  is an enlarged plan view showing the action of a principal portion of the magnetic tape cassette storage case in the opened state. 
         FIG. 11  is a perspective view showing the structure of the magnetic tape cassette storage case according to the fourth embodiment of the present invention in the opened state. 
         FIG. 12  is a cross-sectional view showing the structure and the action of the thick portion. 
         FIG. 13  is a perspective view showing the structure of the magnetic tape cassette storage case according to the fifth embodiment of the present invention in the opened state. 
         FIG. 14  is an enlarged perspective view of the principal portion showing the structure and the action of the thick portion. 
         FIG. 15  is a perspective view of the magnetic tape cassette storage case according to the sixth embodiment of the present invention in the closed state. 
         FIG. 16  is an enlarged view showing the structure of the principal portion of the magnetic tape cassette storage case of  FIG. 15 . 
         FIG. 17  is a magnetic tape cassette storage case according to the seventh embodiment of the present invention in the opened state. 
         FIG. 18  is a cross-sectional view showing the structure of the principal portion of the storage case. 
         FIG. 19  is a perspective view showing the magnetic tape cassette storage case according to the eighth embodiment of the present invention. 
         FIG. 20  is a cross-sectional view taken along the line X—X of  FIG. 19 . 
         FIG. 21  is a perspective view of the magnetic tape cassette storage case according to the ninth embodiment of the present invention. 
         FIG. 22  is a perspective view of the magnetic tape cassette storage case according to the tenth embodiment of the present invention. 
         FIG. 23  is a cross-sectional view taken along the line Y—Y of  FIG. 22 . 
         FIG. 24  is a perspective view of the magnetic tape cassette storage case according to the eleventh embodiment of the present invention. 
         FIG. 25  is a perspective view of the magnetic tape cassette storage case according to the twelfth embodiment of the present invention. 
         FIG. 26  is a perspective view of the magnetic tape cassette storage case according to the thirteenth embodiment of the present invention. 
         FIG. 27  is a perspective view of the magnetic tape cassette storage case according to the fourteenth embodiment of the present invention. 
         FIG. 28  is a perspective view of the magnetic tape cassette storage case according to the fifteenth embodiment of the present invention. 
         FIG. 29  is a perspective view of the magnetic tape cassette storage case according to the sixteenth embodiment of the present invention. 
         FIG. 30  is a perspective view of the magnetic tape cassette storage case according to the seventeenth embodiment of the present invention. 
         FIG. 31  is a perspective view of the magnetic tape cassette storage case according to the eighteenth embodiment of the present invention. 
         FIG. 32(   a ) shows a state in which-the magnetic tape cassette  1081  is inserted upside down by mistake, and (b) is a state in which the lid is closed in the state of (a). 
         FIG. 33  is a drawing showing a state in which the magnetic tape cassette is properly stored in the storage case. 
         FIG. 34  is a drawing showing the storage case of  FIG. 33 , viewed from the direction of P. 
         FIG. 35  is a perspective view of the magnetic tape cassette storage case according to the nineteenth embodiment of the present invention. 
         FIG. 36  is a bottom view of the magnetic tape cassette for Beta cam. 
         FIG. 37  is a modification of the storage case for magnetic tape cassette according to the nineteenth embodiment. 
         FIG. 38  is a perspective view of the magnetic tape cassette storage case, a magnetic tape cassette, and the information sheet according to the twentieth embodiment. 
         FIG. 39  is a partially enlarged perspective view showing the principal portion of the storage case for magnetic tape cassette according to the twentieth embodiment. 
         FIG. 40  is a cross sectional view showing a state in which the magnetic tape cassette and the information sheet is stored in the magnetic tape cassette storage case according to the twentieth embodiment. 
         FIG. 41  is a perspective view of the rib-molding core for molding the holding rib of the magnetic tape cassette storage case according to the twentieth embodiment. 
         FIG. 42  is a drawing showing the principal portion of the metal mold including a rib-molding core for molding the holding rib of the magnetic tape cassette storage case according to the twentieth embodiment, in which  FIG. 42(   a ) is a conceptual cross-sectional view of the holding rib viewed from the front, and  FIG. 42(   b ) is a conceptual cross-sectional view of the holding rib viewed from the side. 
         FIG. 43  is a process drawing showing from molding operation to releasing operation in the metal mold according to the twentieth embodiment, in which  FIG. 43(   a ) is a conceptual cross-sectional view of the molding operation,  FIG. 43(   b ) is a conceptual cross sectional view when the die is opened, and  FIG. 43(   c ) is a conceptual cross-sectional view of releasing operation. 
         FIG. 44  is a perspective view showing the twenty-first embodiment of the present invention. 
         FIG. 45  is a partly enlarged perspective view showing the twenty-second embodiment of the present invention. 
         FIG. 46  is a perspective view showing an example of the storage cases for magnetic tape cassettes of the related art. 
         FIG. 47  is a perspective view showing an example of the magnetic tape cassettes. 
         FIG. 48  is a perspective view showing an example of the magnetic tape cassette storage case of the related art. 
         FIG. 49  is a cross-sectional view showing the construction of the information sheet holding portion of the related art. 
         FIG. 50  is a perspective view showing the structure of the magnetic tape cassette storage case of the related art in the closed state. 
         FIG. 51  is a perspective view showing the structure of the magnetic tape cassette. 
         FIG. 52  is a cross-sectional view showing the structure of the locking projection and the locking recess. 
         FIG. 53  is an enlarged plan view of a principal portion of the magnetic tape cassette storage case showing the action to open the same. 
         FIG. 54  is a perspective view showing an example of the magnetic tape cassette storage case of the related art. 
         FIG. 55  is a perspective view of the magnetic tape cassette to be stored in the magnetic tape cassette storage case. 
         FIG. 56  is a drawing showing a state in which the lid section is deformed when a pressurized force is applied. 
         FIG. 57  is a drawing showing a state in which the storage section and the lid section are not engaged. 
         FIG. 58  is a perspective view showing an example of the magnetic tape cassette storage case of the related art. 
         FIG. 59  is a perspective view of the DVC. 
         FIG. 60  is a side view of the magnetic tape cassettes stored in the storage section upside down. 
         FIG. 61  is a drawing showing a state in which the magnetic tape cassette is properly inserted into the storage section. 
         FIG. 62  is a drawing showing the storage case for storing the magnetic tape cassettes of the related art. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Referring now to the attached drawings, the first embodiment of the present invention will be described. 
       FIG. 1  is a perspective view showing the structure of the storage case for magnetic tape cassette. For the explanation of this embodiment, the magnetic tape cassette shown in  FIG. 47  will be used as appropriate. 
     The storage case  1  is formed, for example, of polypropylene for enabling the hinged movement, and has such a structure that the storage section  3  and the lid section  5  are connected via the connecting section  7 . The storage section  3  comprises a first plate portion  11 , a first sidewall portion  13  formed integrally along the three sides of the outer periphery of the first plate portion  11 , a pair of reel locking ribs  15   a ,  15   b  of hollow cylindrical shape formed on the first plate portion  11  at the positions somewhat closer to the rear side than to the front side, and a opening locking rib  14  formed on the first plate  11  at the position somewhat closer to the front side in a V-shape in cross section. 
     When the magnetic tape cassette  1481  shown in  FIG. 47  is stored, as shown by a phantom line in  FIG. 1 , the magnetic tape cassette  1481  is fitted in the first sidewall portion  13 , and the reel locking ribs  15   b ,  15   a  are inserted and pressed into the circular engaging holes B formed at the centers of the engaging portions  1489   a ,  1489   b  of the magnetic tape cassette  1481 , and simultaneously, the opening  1493  of the magnetic tape cassette  1481  is inserted and pressed into the opening locking rib  14 , so that the magnetic tape cassette  1481  is restricted in position and thus is properly stored. It is also possible to form only one of the reel locking ribs  15   a ,  15   b  and the opening locking rib  14  on the first plate portion  11  of the storage section  3 , or other members having different configuration may be employed for restricting the position of the magnetic tape cassette  1481 . 
     The lid section  5  comprises a second plate portion  21 , and a second sidewall portion  23  formed integrally along the three sides of the outer periphery of the second plate portion  21 . The connecting section  7  comprises thin portions  33   a ,  33   b  on both sides of the third plate portion  31 , which enables the storage section  3  and the lid section  5  to close as a book. 
     Outside of the first sidewall portion  13  that defines the storage section  3 , there is provided an overhanging portion  11   a  that is formed by a part of the first plate portion  11  in an overhanging manner. Therefore, even when the storage section  3  and the lid section  5  are closed, and the second sidewall portion  23  of the lid section  5  is fitted around the first sidewall portion  13  of the storage section  3 , the overhanging portion  11   a  prevents the storage section  3  from getting into the lid section  5 , and thus the thickness of the storage case  1  may be maintained as a whole. 
     The outer surface of the first sidewall portion  13  is formed with a recess  13   a  as a locked portion, and the inner surface of the second sidewall portion  23  is formed with a projection  23   a  as a locking portion at the position corresponding to the recess  13   a  when the storage section  3  and the lid section  5  are closed. Therefore, when the storage section  3  and the lid section  5  are closed with each other, the projection  23   a  and the recess  13   a  engage to prevent an accidental opening of the storage section  3  and the lid section  5 . The positions, the number, and the configurations of the projection  23   a  and the recess  13   a  are not limited to the embodiment shown in  FIG. 1 , but various modifications are possible. 
     As shown in  FIG. 1  and  FIG. 2 , a reinforcing rib  26   a  is formed on the outside of the second sidewall portion  23  of the lid section  5  at the end closer to the connecting section, and a bevel  26   b  is formed at the inside of the rib  26   a  as a cut-off portion having the same height as the height H (shown in  FIG. 1 ) of the second sidewall portion  23  of the lid section  5 . 
     According to the storage case  1  of the present invention, when the storage section  3  and the lid section  5  are closed, even if the second sidewall portion  23  of the lid section  5  formed of polypropylene is in the deflected state shown by a phantom line in  FIG. 2  by a pressurizing force applied in the direction of P, the bevel  26   b  provided on the second sidewall portion  23  of the lid section  5  abuts against the first sidewall portion  13  of the storage section  3 , which ensures that the second sidewall portion  23  of the lid section  5  is fitted on the outside of the first sidewall portion  13  of the storage section  3 . Therefore, imperfect closing of the storage case is prevented by the bevel  26   b . The bevel  26   b  does not have to have the same dimension as the height H of the second sidewall section  23 , or does not have to reach the surface of the plate portion  21 , as far as it has a dimension not less than the height h (shown in  FIG. 1 ) of the first sidewall portion  13  of the storage section  3 . It is because a dimension as described above allows the sidewall portion  23  to be guided to the first sidewall portion  13  smoothly until the lid section  5  is completely closed, even when the sidewall section  23  is deflected. The bevel  26   b  is not limited to a flat surface, but may be a curved surface or the like, for example. 
     The first embodiment is not limited to the magnetic tape cassette storage case for the DVC, but is also applicable to the storage case for storing other types of cassettes. 
     Referring now to the accompanied drawings, the second embodiment of the present invention will be described. 
       FIG. 3  is a perspective view showing an inside structure of the magnetic tape cassette storage case;  FIG. 4  is a perspective view showing the outer structure of the magnetic tape cassette storage case; and  FIG. 5  is a cross-sectional view taken along the line A—A of  FIG. 4 .  FIG. 6  is a perspective view of an example of the magnetic tape cassettes to be stored, viewed from the bottom side. 
     Referring now to  FIG. 6 , the magnetic cassette tape T will be described.  FIG. 6  is a perspective view of the magnetic tape cassette T viewed from the bottom side, and thus the upper cassette half  311  is shown below the lower cassette half  313 . The lower cassette half  313  is formed with circular openings  315   a ,  315   b  at two positions thereof, and the engaging portions  317   a ,  317   b  formed integrally with the reel hubs on which the magnetic tape is wound thereon (not shown) are exposed. These engaging portions  317   a ,  317   b  have a function to unwind and wind the magnetic tape when it is mounted in the recording/playing apparatus, and a function to be fitted on the reel locking rib to prevent rattling of the magnetic tape cassette T when it is stored in the storage case  271 . 
     On the front side of the magnetic tape cassette T, an outer lid  321  is provided for pivotal movement, and when it is mounted in the recording/playing apparatus, the magnetic tape is pulled out after the outer lid  321  is pivoted as shown by the arrow A in  FIG. 6 . There is formed a recessed front opening  323  inside the outer lid  321  at near the center in such a manner that the upper and lower cassette halves  311 ,  313  are notched, and there is provided a shoulder  325  on one end of the front opening  323  on one end of the front opening  323 . Both of them have a function of positioning when the magnetic tape cassette T is mounted in the recording/playing apparatus. 
     Referring now to  FIG. 3  to  FIG. 5 , the storage case will be described. The storage case  101  is formed integrally of synthetic resin, and the storage section  103  and the lid section  105  are connected via the connecting section  107 . 
     The storage section  103  comprises a first plate portion  211 , a first sidewall portion  213  formed along three sides of the outer periphery thereof, a wrong insertion preventing rib  215  formed on the first plate portion  211  near the connecting section  107 , a pair of reel locking rib  229   a ,  229   b . When the magnetic tape cassette T is properly stored in the storage case  101 , it is fitted within the sidewall portion  213  as shown by a phantom line in  FIG. 3 . 
     The lid section  105  comprises a second sidewall portion  223  formed integrally along three sides of the outer periphery of the second plate portion  211 , a locking projection  223   a  formed on the inner surface of the second sidewall portion  223 , and a cassette holding rib  225  and a reinforcing rib  227  formed at the corner between the second plate portion  221  and the second sidewall portion  223 . 
     The connecting section  107  comprises thin portions  233   a ,  233   b  formed on both sides of the third plate portion  231  for hinged movement, and cassette holding ribs  235   a ,  235   b  formed in the vicinity of both ends of the third plate portion  231 . When the storage section  103  and the lid section  105  are closed, both sides of the connecting section  107  are bent so that the storage section  103  and the lid section  105  can be closes as a book (See  FIG. 4 ). 
     Outside of the first sidewall portion  213  constituting the storage section  103 , there is provided an overhanging portion  211   a  that is formed by a part of the first plate portion  211  in an overhanging manner. Therefore, even when the storage section  103  and the lid section  105  are closed, and the second sidewall portion  223  of the lid section  105  is fitted around the first sidewall portion  213  of the storage section  103 , the over hanging portion  211   a  prevents the storage section  103  from getting into the lid section  105 , and thus the thickness of the storage case  101  may be maintained as a whole. The outer surface of the first sidewall portion  213  is formed with a recessed locking portion  213   a.    
     On the other hand, the locking projection  223   a  formed on the lid section  105  is formed on the inner surface of the second sidewall portion  223  at the position corresponding to the locking portion  213   a  when the storage section  103  and the lid section  105  are closed. Therefore, when the storage section  103  and the lid section  105  are closed with each other, the locking projection  223   a  is locked to the locking portion  213   a  to prevent the storage section  103  and the lid section  105  from being separated. The positions and the numbers of the locking portion  213   a  and the locking portion  223   a  to be formed are not limited to the embodiment shown in  FIG. 3 , but various modifications may be made. 
     The wrong insertion preventing rib  215  serves to store the magnetic tape cassette T in the storage case  101  and prevent rattling when the lid section  105  is closed as shown in  FIG. 4 . The wrong insertion preventing rib  215  engages the front opening  323  of the magnetic tape cassette T. The reel locking ribs  229   a ,  229   b  engage the holes B formed at the centers of the engaging portions  317   a ,  317   b  of the magnetic tape cassette T. The wrong insertion preventing rib  215  and the reel locking ribs  229   a ,  229   b  enables the magnetic tape cassette T to be stored in the storage case  101  without applying undue force to the magnetic tape cassette T and without rattling. 
     The information sheet holding portion  241  will now be described. 
     According to  FIG. 3 , the information sheet holding portion  241  is formed over the backside of the storage section  103  and the connecting section  107 . Therefore, in a state where the storage section  103  and the lid section  105  are closed with the storage section  103  placed upside, the information sheet holding portion  241  is appeared on the upper surface of the storage case  101  as shown in  FIG. 4  and  FIG. 5 . 
     The information sheet holding portion  241  comprises a flat portion  243  formed over the backside of the first plate portion  211  constituting the storage section  103 , a flat portion  245  formed over the backside of the third plate portion  231  constituting the connecting section  107 , rib  247  formed along three sides of the flat portion  243 , ribs  249   a ,  249   b  formed on both sides of the flat portion  245 , and a sheet  251  welded so as to partly cover the flat portions  243 ,  245 . 
     Describing the positions of the ribs  247 ,  249   a  according to  FIG. 3 , the rib  247  corresponds to the lower side of the overhanging portion  211   a , and the rib  249   a  corresponds to the back surface of the cassette holding rib  235   a  on the viewer&#39;s side. 
     The seat  251  is formed of flexible transparent synthetic resin. One end of the seat  251  is welded to the flat portion  243  at the welding position a along the rib  247  shown by a dot dash line in  FIG. 4 , and the other end is welded to the welding position b shown by a dot dash line. The welding position b is located at about the backside of the groove portion  233   a.    
     When the magnetic tape cassette T is stored in the storage case  101 , the information sheet  253  on which the recorded contents or the like are listed is inserted into the information sheet holding portion  241 . In this embodiment, the problem described above does not occur at all. 
     In other words, even when the information sheet  253  is larger than the sheet  251 , it runs along the flat portions  243 ,  245  as far as it is the size that can be accommodated in the rib  247 . Therefore, it is neither deformed nor protruded from the rib  247 , and thus dirt or damage of the information sheet  253  can be prevented. 
     When the number of information sheets  253  is increased, the sheet  251  stretches. However, as far as the information sheet  253  can be housed within the height of the ribs  247 ,  249   a ,  249   b , it is never rubbed directly, thereby preventing dirt and damage as described above. Therefore, when it is placed, for example, on the desk with the upper surface shown in  FIG. 4  and  FIG. 5  faced down, the information sheet  253  does not come in direct contact with the desk or the like. Even when it is placed on top of another, prevention of dirt and damage is achieved. 
     In contrast to it, when the information sheet  253  was small and was entered completely under the sheet  251 , it was troublesome to take it out in the related art. However, according to this embodiment, all the user have to do is just to insert his/her finger under the sheet  251  and pulled it out along the flat portions  243 ,  245  in the lateral direction. 
     As is described thus far, the storage case  101  of this embodiment is able to prevent dirt or damage of the information sheet  253  irrespective of the size or the number of the information sheet  253 , and is easy to load and to take out the information sheet  253 . Even when many pieces of information sheets  253  are loaded, it is easy to take them out, thereby improving usability of the storage case  101  itself. 
     Though the second embodiment has been described thus far, the present invention is not limited thereto. 
     For example, the information sheet holding portion  241  formed by covering a part of the flat portion with a sheet may be provided on the backside of the lid section  105 . Likewise, it may be provided all over the backsides of the storage section  103 , the connecting section  107 , and the lid section  105 . In this case, a rib that projects to the higher position than the level of the transparent sheet is provided at least along a part of the periphery of the plate portion constituting the information sheet holding portion. 
     Referring now to the attached drawings, the third embodiment of the present invention will be described. 
       FIG. 7  is a perspective view showing the structure of the storage case;  FIG. 8  is a perspective view of the storage case in a closed state;  FIG. 9  is a cross-sectional view showing the structure of the principal portion of the storage case; and  FIG. 10  is a plan view of a principal portion of the storage case illustrating the opening operation. 
     The structure of the storage case of the present invention is the same as the storage case  1850  shown in  FIG. 50  except for the portions that are the characteristics of the present invention. Therefore, the portions other than the characteristics of the present invention will not be described here unless otherwise specially required. 
       FIG. 7  shows the storage case  520  for magnetic tape cassettes according to the third embodiment of the present invention in the opened state, and  FIG. 8  is a perspective view showing in the closed state. In the storage case  520 , the second sidewall portion  409  constituting the lid section  402  is formed with thick portion  521  on the outer wall surface thereof. The thick portion  521  is formed at the position corresponding to the outside of the locking projection  409   b  in this embodiment, and the length thereof is the same as the second sidewall portion  409  and the width W is lightly wider than the width of the locking projection  409   b.    
     According to this structure, when the storage case  520  is closed as shown in  FIG. 8 , the locking projection  409   b  engages with the locking recess  405   b , and the outside of the engaging position is covered by the thick portion  521 . Since the thickness t of the thick portion  521  corresponds to the sum of the thickness t 1  of the second sidewall portion  409  and the height h 1  of the first and second overhanging portions  404   a ,  408   a  as shown in  FIG. 9 , they are flush with each other over the width W at the position where the thick portion  521  is formed. Therefore, when the storage case  520  is opened, the user holds the portion other than the thick portion  521  with his/her fingers as shown in  FIG. 10  since the portion where the thick portion  521  is formed is slippery for holding with his/her fingers. 
     In other words, in the structure of this embodiment, when the storage case  520  is opened, the position where the user holds deviates from the locking position between the locking projection  409   b  and the locking recess  405   b . In addition, providing the thick portion  521  enforce the portion of the second sidewall portion  409  where the locking projection  405  is formed. Therefore, as shown by a phantom line in  FIG. 10 , even when the user puts power into the first and second overhanging potions  404   a ,  408   a  with fingers in order to open the storage case  520 , the locking projection  409   b  is not pressed toward the locking recess  405   b , and thus it can be opened smoothly. 
     Referring now to  FIG. 11  and  FIG. 12 , the fourth embodiment of the present invention will be described.  FIG. 11  is a perspective view showing the structure of the storage case in the opened state, and  FIG. 12  is a cross-sectional view of the principal portion showing the locked state. The difference between this embodiment and the third embodiment is that the locking structure is provided in addition to the thick portion  521 . Therefore, the portions other then the characteristics of this embodiment will not be described here unless otherwise specially required. 
     The storage case  520  of this embodiment is formed with a locking recess  405   c  on the first overhanging portion  404   a , and a locking projection  409   c  is provided at the position corresponding to the locking recess  405   c  when the end portion of the second sidewall portion  409 , or the lid section  402 , is closed as shown in  FIG. 11  by enlarging the principal portion. In this structure, when the storage section  401  and the lid section  402  are closed as shown in  FIG. 12 , the rocking projection  409   b  engages the locking recess  405   b , and the locking projection  409   c  engage the locking recess  405   c.    
     On the other hand, when the storage case  520  is opened, since there is provided a thick portion  521  as in the case of the first embodiment, the user tries to open the case by holding the storage case  520  with his/her fingers placed at the overhanging portions  404   a ,  408   a , which is deviated from the thick portion  521 , as is described in conjunction with  FIG. 10 . 
     In this case, even when the user puts power into his/her fingers, the storage case can be opened easily by the following two actions. The first action is that the thick portion  521  prevents the second sidewall portion  409  from being deformed, so that it resists the pressing action of the locking projection  409   b  with respect to the locking recess  405   b . The second action is that the locking projection  409   c  provided at the end of the second sidewall portion  409  engages the locking recess  405   c , so that it resists pressing. 
     Therefore, when the user tries to open the storage case  520 , the multiplier effect of the first and the second reasons eliminate deflected deformation of the thick portion  521 , and thus of the entire second sidewall portion  409 , thereby facilitating the operation to open the storage case  520 . 
     Referring now to  FIG. 13  and  FIG. 14 , the fifth embodiment of the present invention will be described.  FIG. 13  is a perspective view showing the structure of the storage case in the opened state, and  FIG. 14  is a perspective view, partly in cross-section, of the principal portion showing the locked state. The difference between this embodiment and the first embodiment is that the locking structure is provided in addition to the thick portion  521 . Therefore, the portions other than the characteristics of this embodiment will not be described here unless otherwise specially required. 
     The storage case  520  in this embodiment is, as shown in  FIG. 13  by enlarging the principal portion, provided with two locking recesses  405   c  on the first overhanging portion  404   a , and two locking projections  409   c  are provided at the positions corresponding to the locking recesses  405   c  when the end of the second sidewall portion  409 , or the lid section  402 , is closed. Two locking recesses  405   c  are provided on both sides of the locking recess  405   b , and two locking projections  409   c  are provided on both sides of the thick portion  521 . 
     In this structure, when the storage section  401  and the lid section  402  are closed, as shown in  FIG. 14 , the locking recess  405   b  engages the locking projection  409   b , and the locking projection  409   c  engages the locking recess  405   c  on both sides of the thick portion  521 , in other words, at the position where the user places his/her fingers on when the storage case  520  is opened. 
     When the storage case  520  is opened, since there is provided a thick portion  521  as in the case of the third embodiment, the user tries to open the case by holding the storage case  520  with his/her fingers placed at the overhanging portions  404   a ,  408   a , which is deviated from the thick portion  521 , as is described in conjunction with  FIG. 10 . 
     In this case, even when the use puts power into his/her fingers, the storage case can be opened with the following two actions. The first action is that the thick portion  521  prevents the second sidewall portion  409  from being deformed, so that it resists the pressing action of the locking projection  409   b  with respect to the locking recess  405   b . The second action is that the locking projection  409   c  provided at the end of the second sidewall portion  409  engages the locking recess  405   c  at the position where the fingers are placed, so that it resists pressing. 
     Therefore, when the user tries to open the storage case  520 , even when he/she puts power into his/her fingers, the second sidewall portion  409  is not deformed because the locking projection  409   c  is supported by the locking recess  405   c . In addition, since the thick portion  521  is provided, the position where the locking projection  409   b  and the locking recess  405   b  are engaged is not subjected to a force, and thus the storage case  520  can easily be opened. 
     Though the third to fifth embodiments has been described thus far, the present invention is not limited to those embodiments, but various deformations may be made. For example, it is also applicable to make the whole portion of the second sidewall on which the locking projection is formed thicker, and form a recess on a part of it for placing a finger. Alternatively, when the position of the locking projection and the locking recess is not at the center of the elongated side of the sidewall portion as in the case of the third to fifth embodiments, the same action and effect can be expected by forming a thick portion at the position corresponding to the position of the locking projection and the locking recess as a matter of course. 
     Referring now to  FIG. 15  and  FIG. 16 , the sixth embodiment of the present invention will be described.  FIG. 15  is a perspective view of the storage case in closed state,  FIG. 16  is an enlarged view showing the structure of the principal portion of the storage case shown in  FIG. 15 . The different point between this embodiment and the third to fifth embodiments is that the notches  404   c ,  408   c  are provided to be flush with the sidewall portion  409  instead of the thick portion  521 . Therefore, the portions other than the characteristics of this embodiment will not be described here unless otherwise specially required. 
     The storage case  520  in this embodiment is, as shown in  FIG. 15  and  FIG. 16 , formed with notches  404   c ,  408   c  on the first and second overhanging portions  404   a ,  408   a  respectively. The notches  404   c ,  408   c  are formed at the positions corresponding to the outside of the locking projection  409   b  and the locking recess  405   b  in this embodiment, and the width is slightly wider than the width of the locking projection  409   b . There are also provided arrows  525   a ,  525   b  indicating the directions to open the storage case on both sides of the notches  404   c ,  408   c . These arrows  525   a ,  525   b  aid the user to know the position to open. These arrows  525   a ,  525   b  may be provided in the third to fifth embodiments described above, but it is not necessarily required to provide these arrows  525   a ,  525   b.    
     In this arrangement, since the portions of the first and second overhanging portions  404   a ,  408   a  where the notches  404   c ,  408   c  are formed are flush with the sidewall portion  409 , even if the user placed his/her fingers on the position where the notches  404   c ,  408   c  are formed, it is slippery, and thus the user place his/her fingers on the positions deviated from the notches  404 c,  408   c , or more specifically, on the first and the second overhanging portions  404   a ,  408   a  in the vicinity of the arrows  525   a ,  525   b . Therefore, even when the user places his/her fingers on the first and the second overhanging portions  404   a ,  408   a  and put power into his/her fingers to open the storage case  520 , the locking projection  409   b  is not pressed toward the locking recess  405   b  and thus the storage case  520  can be opened smoothly. 
     The seventh embodiment of the magnetic tape cassette storage case is described in detail.  FIG. 17  is a perspective view showing the structure of the storage case, and  FIG. 18  is a cross-sectional view showing the principal structure of the storage case. 
     The structure of the storage case of this embodiment is the same as the storage case  1850  shown in  FIG. 50  except for the portions that are the characteristics of the present invention. Therefore, the portions other than the characteristics of the present invention will not be described here unless otherwise specially required. 
       FIG. 17  is a storage case  580  for magnetic tape cassette  580  according to the seventh embodiment of the present invention in the opened state. In the storage case  580 , a recess  539   c  is formed on the outer wall surface of the second sidewall portion  539  constituting the lid section  532 . On the other hand, the first sidewall portion  535  is formed along two sides of the outer periphery of the first plate portion  534  constituting the storage section  531 , and a locking projection  548  projecting inwardly is formed thereon as well. The second sidewall portion  539  is larger in width in comparison with the locking projection  548  described above, so as to facilitate the user to place his/her fingers. 
     In this arrangement, when the storage case  580  is closed as shown in  FIG. 18 , the tip portion of the locking projection  548  engages the locking recess  539   c . When the storage case  520  is opened, the user places his/her fingers on the first and the second overhanging portions  534   a ,  538   a  and presses on the thicker portion, or the second sidewall portion  539 , in the direction B. Then the second sidewall portion  539  deflects in the direction B. As a consequent, the locking recess  539   c  moves in the direction B to release the engagement with the locking projection  548 , and thus the storage case can be opened smoothly. 
     The magnetic tape cassette to be stored in the embodiment described above is not limited to the DVC, but other magnetic tape cassette may be stored by modifying the dimensions of the respective parts and the locking structure. 
     Referring now to the attached drawings, the eighth embodiment of the present invention will be described. 
     The structure of the storage case of this embodiment is the same as the storage case  2150  shown in  FIG. 54  except for the portions that are the characteristics of the present invention. Therefore, the portions other than the characteristics of the present invention will not be described or will be simplified here unless otherwise specially required. 
       FIG. 19  is a perspective view of the magnetic tape storage case according to the eighth embodiment of the present invention. The characteristic structure of this embodiment includes fitting portions  715   a ,  715   b.    
     Referring now to  FIG. 20 , the fitting portions  715   a ,  715   b  will be described.  FIG. 20  is a cross-sectional view taken along the line X—X in  FIG. 19 , viewed in the direction shown by the arrow D 1 . However, the storage case  801  is in the closed state and the magnetic tape cassette is not stored therein. As is apparent from  FIG. 20 , the positioning ribs  712   a ,  712   b  fit on the fitting recesses  711   a  and  711   b  respectively, and the fitting portions  715   a ,  715   b , which are in parallel with the positioning ribs  712   a ,  712   b  and extend inside the positioning ribs  712   a ,  712   b , abut against the inner surface of the first sidewall portion  605 . In this arrangement, the second sidewall portion  609  and the fitting portions  715   a ,  715   b  clamp the first sidewall portion  605  and the engaging recesses  711   a ,  711   b , and as a consequent, displacement or deformation of the second sidewall portion  609  in the lateral direction in  FIG. 20  is prevented. In addition, the fitting portions  715   a ,  715   b  serve as a deformation and displacement preventing member for the positioning ribs  712   a ,  712   b.    
       FIG. 21  shows a magnetic tape storage case  802  according to the ninth embodiment of the present invention. The characteristic structure of the present invention includes fitting portions  715   a ,  715   b  and a locking mechanism  717   a ,  717   b . The locking mechanism comprises a projection  717   a  and a recess  717   b , which are disposed at the longitudinal center of the second sidewall portion  609  and the first sidewall portion  605  respectively. In this embodiment, the projection  717   a  is formed on the lid section  602 , and the recess  717   b  is formed on the storage section  601 . However, it is also possible to form the recess on the lid section  602  and the projection on the storage section  601 . With the provision of the locking mechanism, even when a vertically pressurizing force is applied to the plate potion of the storage case  802 , irregular opening of the storage case can be prevented. By preventing irregular opening, the unforeseen resilient deformation of the sidewall portions  605 ,  609  can be prevented, and thus displacement or deformation of the sidewall portion of the storage case as a result of the resilient deformation may be prevented. 
       FIG. 22  shows a magnetic tape storage case  803  according to the tenth embodiment of the present invention. The characteristic structure of this embodiment includes a fitting groove  716 . The elongated portion, which faces to the connecting section  603  in parallel when the case is closed, of the second sidewall portion  609  of the lid section  602  is molded so as to fit into the fitting groove  716 . More specifically, the width to the edge of elongated portion is formed relatively wider than other portions. 
     Referring now to  FIG. 23 , the fitting groove  716  will be described.  FIG. 23  is a cross-section taken along the line Y—Y in  FIG. 22 . The storage case  803  is in the closed state, and the magnetic tape cassette is not stored herein. As is apparent from  FIG. 23 , the edge of the second sidewall portion  609  is fitted in the fitting groove  716  extending on the overhanging portion  604   a . With this fitting, displacement and deformation in the lateral direction in  FIG. 22  can be prevented. In addition, though the fitting groove  716  that fits with the elongated portion of the second sidewall portion  609  is shown in this embodiment, it is also conceivable that a fitting groove in which the shorter portion of the second sidewall portion  709  is fitted is further provide. 
     In  FIG. 24 , the storage case for magnetic tapes  804  according to the eleventh embodiment of the present invention is shown. The characteristic structure of this embodiment includes fitting portions  715   a ,  715   b  and a fitting groove  716 . 
       FIG. 25  shows a storage case for magnetic tapes  805  according to the twelfth embodiment of the present invention. The characteristic structure of this embodiment includes a fitting groove  718  and a locking mechanism  717   a ,  717   b.    
       FIG. 26  shows a storage case for magnetic tapes  806  according to the thirteenth embodiment of the present invention. The characteristic structure of this embodiment includes a fitting grooves  716   a ,  716   b . This embodiment is characterized in that two fitting grooves  716   a ,  716   b  exist, and in that the two portions of the second sidewall portion  609  are formed slightly wider in order to be fitted in the fitting grooves  716   a ,  716   b . In addition, though the fitting grooves  716   a ,  716   b  to be fitted with the elongated portion of the second sidewall portion  609  is shown in this embodiment, it is also conceivable that the fitting groove in which the shorter portion of the second sidewall portion  609  is fitted is further provided. 
       FIG. 27  shows a storage case for magnetic tapes  807  according to the fourteenth embodiment of the present invention. The characteristic structure of this embodiment includes the fitting portions  715   a ,  715   b , and the fitting grooves  716   a ,  716   b.    
       FIG. 28  shows a storage case for magnetic tapes  808  according to the fifteenth embodiment of the present invention. The characteristic structure of this embodiment includes fitting grooves  716   a ,  716   b  and a locking mechanism  717   a ,  717   b.    
       FIG. 29  shows a storage case for magnetic tapes  809  according to the sixteenth embodiment of the present invention. The characteristic structure of this embodiment includes fitting portions  715   a ,  715   b , a fitting groove  716 , and a locking mechanism  717   a ,  717   b.    
       FIG. 30  shows a storage case for magnetic tapes  810  according to the seventeenth embodiment of the present invention. The characteristic structure of this embodiment includes fitting portions  715   a ,  715   b , fitting grooves  716   a ,  716   b , and a locking mechanism  717   a ,  717   b.    
     The embodiments described above may be applied to the magnetic tape cassettes other than the DVC. 
     Referring now to the drawings, the eighteenth embodiment of the present invention will be described. 
       FIG. 31  is a perspective view showing a storage case for magnetic tapes  1020  according to the eighteenth embodiment of the present invention. The same structure as the storage case  2350  of the related art will not be described, or will be briefly described. 
     The storage case  1020  of the eighteenth embodiment is formed integrally of synthetic resin, in which the storage section  901  and the lid section  902  are connected via the connecting section  903 . The storage section  901  comprises a first plate portion  904 , a sidewall portion  905  formed integrally along the outer periphery of the first plate portion  904 , a recess locking rib  1017  of V-shape in cross section formed on the first plate portion  904  closer to the front edge, and a pair of reel locking ribs  1016   a ,  1016   b  that engage reel hubs of the magnetic tape cassette  2381 . When the magnetic tape cassette  1081  is stored properly, it is loosely fitted within the sidewall portion  905  as shown by a phantom line in  FIG. 31 . 
     The recess locking rib  1017  is described now. The recess locking rib  1017  is not fitted in the front opening  2393  shown in  FIG. 59 , but fitted in the shoulder  2395 . Therefore, the height of the recess locking rib  1017  is set to almost the same dimension as the depth of the shoulder  2395 , and the curvature of the side surface of the recess locking rib  1017  is set to almost the same as the curvature of the edge of the shoulder  2395 . Since the depth of the engaging hole B shown in  FIG. 59  is deeper than the depth of the shoulder  2395 , the height of the recess locking rib  1017  is set to be smaller than the height of the reel locking ribs  1016   a ,  1016   b . The recess locking rib  1017  is formed at the rear of the cassette with respect to the top lid  2397 . 
     When the magnetic tape cassette  2381  is stored in the storage case  1020  of the present invention, the front opening  2393  is faced downward, which is upside down of the magnetic tape cassette shown in  FIG. 59 , so that the magnetic tape cassette  2381  is inserted into the sidewall portion  905  with the shoulder  2395  faced toward the recess locking rib  1017  and the reel locking ribs  1016   a ,  1016   b  faced toward the engaging hole B. 
     When the magnetic tape cassette  2381  is inserted upside down in a wrong way as shown in  FIG. 32(   a ), since the recess locking rib  1017  is formed at the rear of the cassette with respect to the top lid  2397 , the top lid  2397  and the recess locking rib  1017  do not abut against each other as shown in  FIG. 32(   b ) even if the magnetic tape cassette  2381  is pressed by closing the lid  902 . Therefore, deformation and damage of the top lid  2397  may be prevented and thus deformation and damage of the outer lid and the inner lid that are connected thereto may also be prevented to ensure the protection of the magnetic tape. 
     Since the rib is not formed with an opening locking portion and the height of the recess locking rib  1017  is set to be lower in comparison with the related art, even when the user inserted the magnetic tape cassette  2381  into the storage section  901  in the state of being shifted backward of the cassette, or in the direction B (shown in  FIG. 32(   a )), a undue pressing force caused by the height of the rib  7  as shown in  FIG. 60  is not applied. Therefore, the deformation and damage of the top lid  2397  may be prevented. Even when it is inserted into the storage section  901  of the storage case  1020  in the proper orientation but in the state of being shifted in the direction B by mistake, a undue pressing force caused by the height of the rib is not applied to the inner lid connected to the inner surface of the top lid  2397  because the height of the recess locking rib  1017  is set to be low, thereby preventing deformation and damage of the inner lid. 
     The characteristic structure of the eighteenth embodiment other than those stated above will be described.  FIG. 33  is a magnetic tape cassette properly stored in the storage case, and  FIG. 34  is a storage case in  FIG. 33  viewed from in the direction P. As shown in  FIG. 33 , the distance between the reference ring  2312   b  of the lower reel  2312  constituting the tape reel  2310  and the circular opening  2387   b  formed on the lower half  2385  is determine to be b. The distance between the engaging hole B of the hub  2315  and the reel locking rib  1016   a  is set to a. The relation between these distances a and b is set to a&gt;b. In such a dimensional relation, when the storage case drops, the reel reference ring  2312   b  comes into collision with the wall of the circular opening  2387   b  of the lower half  2385  in a first place. Then, after absorbing the impact by collision, a load of the engaging hole B of the hub  2315  acts on the reel locking rib  1016   a , thereby preventing an excessive load from being applied. 
     The distance between the rear surface of the cassette and the sidewall portion  905  of the storage section  901  facing thereto is set to c, and the distance between the shoulder  2395  of the cassette and the recess locking rib  1017  is also set to c. In addition, as shown in  FIG. 34 , the distance between the both surfaces of the cassette and the sidewall portion  905  of the storage section  901  facing thereto are also set to c. In other words, the clearance where the storage case and the cassette come into contact is uniform. 
     Therefore, since a load applied under vibration is uniform, and thus occurrence of scratches or powder due to rubbing between the storage case and the cassette can be dispersed. 
     The nineteenth embodiment of the present invention will be described.  FIG. 35  is a perspective view of the storage case  1041  for Beta cam according to the nineteenth embodiment of the present invention, and  FIG. 36  is a bottom view of the magnetic tape cassette  1100  for Beta cam. 
     The storage case  1041  shown in  FIG. 35  comprises a storage section  1043  for storing the magnetic tape cassette  1100  shown in  FIG. 36 , a lid section  1045 , and a connecting section  1047 . The storage section  1043  comprises a first plate portion  1051 , a first sidewall portion formed integrally along the outer periphery of the first plate portion  1051 , reel locking ribs  1055   a ,  1055   b  formed on the first plate portion  1051  at the position somewhat closer to the rear end, and a recess locking rib  1057  formed at the position somewhat closer to the front end. When the magnetic tape cassette  1100  is stored properly, it is loosely fitted within the first sidewall portion  1053  as shown in a phantom line in  FIG. 35 . 
     The recess locking rib  1057  will be described here. The recess locking rib  1057  is formed in the shape of a plate, on which the front opening  1103 , or the recess, shown in  FIG. 36  is fitted. The height of the recess locking rib  1057  is set to the height lower than the reel locking ribs  1055   a ,  1055   b , and the side surface is formed along the flat portion  1103   p  of the front opening  1103 . The recess locking rib  1057  is formed at the rear of the cassette with respect to the lid, so that it does not abut against the single-type lid  1107  when the cassette is inserted upside down by mistake. Therefore, the nineteenth embodiment may prevent deformation and damage of the lid  1107 , and ensures protection of the magnetic tape. 
       FIG. 37  shows a modification of the nineteenth embodiment. Since the structure is the same as the nineteenth embodiment except for the recess locking rib  1067 , the description will be omitted. As shown in  FIG. 37 , the recess locking rib  1067 , which is the characteristic of this modification, comprises a plate portion  1067   b  and a curved portion  1067   a , so that it can be inserted into the front opening  1103  shown in  FIG. 36 . The height of-the recess locking rib  1067  is set to the height lower than the height of the reel locking ribs  1055   a ,  105   b , the plate portion  1067   b  has a side surface along the flat portion  1103   p  of the front opening  1103 , and the curved portion  1067   a  has a side surface along the curved portion  1103   c . The recess locking rib  1067  is located at the position where it does not abut against the single-type lid  1107  when the cassette is inserted upside down by mistake. Therefore, with this modification, deformation and damage of the lid  1107  may be prevented, thereby ensuring the protection of the magnetic tape. 
     For example, the recess locking rib may be applied to the magnetic tape cassette other than the DVC or Beta cam by modifying the configuration as appropriate without limited to the eighteenth and nineteenth embodiments and the dimensional relation described above may be applied as a matter of course. 
     Referring now to the attached drawings, the twentieth embodiment of the present invention will be described. 
       FIG. 38  is a perspective view showing a storage case for magnetic tape cassettes, a magnetic tape cassette, and an information sheet according to the second embodiment according to the twentieth embodiment;  FIG. 39  is a partially enlarged perspective view showing a principal portion of the storage case for magnetic tape cassette according to the twentieth embodiment; 
       FIG. 40  is a cross-sectional view showing the magnetic tape cassette storage case with the magnetic tape cassette and the information sheet stored therein;  FIG. 41  is a perspective view of the metal mold according to the twentieth embodiment showing the rocking state of the rib-molding core;  FIG. 42(   a ), ( b ) are conceptual cross-sectional views showing the principal portion of the metal mold including the rib-molding core for molding the principal portion of the magnetic tape cassette storage case according to the twentieth embodiment; and  FIG. 43(   a ), ( b ), ( c ) are the principal portion of the metal mold including the rib-molding core for molding the principal portion of the storage case for magnetic tape cassette according to the twentieth embodiments showing a state where the rib-molding core is pivoted. 
     As shown in  FIG. 38 , the magnetic tape cassette storage case  1210  are formed by injection molding, and comprises a storage section  1212  for storing the magnetic tape cassette A, and a lid section  1216  in which one side is integrally connected to one of the longitudinal sides of the storage section  1212  via the connecting section  1214 . 
     The storage section  1212  is formed in a rectangular shape corresponding to the outer dimension of the magnetic tape cassette A, and comprises a bottom plate  1222 , or the first plate portion, having a plurality of mounting projections  1218 ,  1220  corresponding to the recessed shape of the magnetic tape cassette A therein, and sidewalls  1224 ,  1224  and the end wall  1226 , or the first sidewall portion, formed so as to extend upwardly along the periphery of the bottom plate  1222  to which the magnetic tape cassette is fitted. A positioning notch  1228  and a locking recess  1230  for engaging the lid section  1216  are formed on the upper edge of and on the outside surface of the sidewall  1224 , and a positioning notch  1232  and the locking recess  1234  to be engaged with the lid section  1216  are also formed on the upper end of and at the center of the outside surface of the end wall  1226 . 
     Both of the elongated sides of the connecting section  1214  are integrally connected to the bottom plate  1222  of the storage section  1212  and the lid section  1216  respectively via the thin portions  1236 ,  1238  so that it can be folded and deployed. 
     The lid section  1216  comprises a top plate  1240 , or the second plate portion, connected to the connecting section  1214  for enabling the hinged movement, and sidewalls  1242 ,  1242  and the end wall  1244 , or the second sidewall portion, that is formed on the inner surface of the top plate  1240 , that is, to extend upwardly like a frame along three sides of the surface opposing to the storage section  1212  and fits around the outside of the sidewall  1224  and the end wall  1226  of the storage section  1212 . The heights of the sidewall  1242  and of the end wall  1244 , and the width (height) of the connecting section  1214  correspond to the sum of the thickness of the magnetic tape cassette A and the storing thickness of the information sheet B. 
     The sidewall  1242  is formed with a positioning rib  1246  inside thereof and a locking claw  1248  for resiliently engages the notch  1228  and the recess  1230  on the storage section  1212  to hold the lid in the closed state, and the end wall  1244  is also formed with a positioning rib  1250  and locking claw  1252  for resiliently engaging the notch  1232  of the storage section  1212  for holding the lid in the closed state at both ends and at the center of the inner surface thereof. 
     In addition, a holding ribs  1254 ,  1256  extending from the top plate  1240  along the sidewalls  1242 ,  1242  are formed on the inner surface of both of the sidewalls  1242 ,  1242  to the appropriate height to abut against the upper peripheral edge of the magnetic tape cassette A to be stored in the lid section  1216  for ensuring the space for storing the information sheet B. 
     The holding ribs  1254 ,  1256  have bevels on the tip portions thereof, so that the bevels  1254   a ,  1256   a  guide the magnetic tape cassette A toward the center of the storage section  1212 . From between the holding ribs  1254 ,  1256 , the holding rib  1254  is provided with a sheet holding rib  1258  for holding the information sheet B integrally projecting from the bevel  1254   a  inwardly (in the vertical direction with respect to the inner surface of the sidewall  1242 ) of the lid section  1216  so that the rib  1258  defines the space  1260  (undercut portion) for holding the information sheet B with the lid plate  1240  as shown in  FIG. 39  in an enlarged state. 
     As shown in  FIG. 39 , the holding rib  1254  is formed along a pedestal  1262  formed on the top plate  1240  and a back holder  1264  formed on the sidewall  1242 . The pedestal  1262  has a uniform height of h and the back holder  1264  is inclined by the angle β with respect to the inner surface of the sidewall  1242 . The height and inclination are formed in such a manner that it does not come into contact with the top plate  1240  and the sidewall  1242  when the rib-molding core of the metal mold described later makes a rocking movement, in other words, to the height h of 50–300 μm and the inclination β of 0.1–3 degrees. The sidewall  1242  is also formed with a draft angle α. 
     In the magnetic tape cassette storage case  1210  in this arrangement, the magnetic tape cassette A is positioned on the bottom plate  1222  of the storage section  1212  with the recessed portion fitted on the mounting projections  1218 ,  1220  of the storage section  1212 , and the information sheet B is positioned between the holding ribs  1254 ,  1256  of the lid section  1216  and one end thereof is restrained by the sheet holding rib  1258 . Then it is closed by folding the thin portions  1236 ,  1238  of the connecting section  1214  to face the lid section  1216  to the storage section  1212 , engaging the positioning ribs  1246 ,  1250  on the lid section  1216  with the positioning notches  1228 ,  1232  on the storage section  1212 , engaging the locking claw  1248  of the lid section  1216  with the locking recess  1234 , and engaging the locking claw  1252  of the lid section  1216  with the locking recess  1243  of the storage section  1212 . 
     In such a closed state, as shown in  FIG. 40 , one end of the information sheet B is positioned by the inner surface of the holding rib  1256 , the other end of the information sheet B is positioned by the inner surface of the holding rib  1254 , and the information sheet B is restrained in the space  1260  by the sheet holding rib  1258 . 
     The dimensions of the information sheet B in length and width correspond to the inner dimensions of the lid section  1216 , and thus it is folded a plurality of times or bound into a leaflet as shown in  FIG. 38 . Therefore, by inserting the end of the sheet into the space  1260  between the lower portion of the sheet holding rib  1258  and the inner surface of the lid plate  1240  as shown in  FIG. 40 , it is stored in the fixed state in terms of position by the lib  1258 , thereby preventing jumping out, dropping off, or protruding thereof. 
     The magnetic tape cassette storage case  1210  is molded by injection molding by the use of the metal mold  1270 . The metal mold  1270  for molding the storage case  1210  performs molding with a fixed die  1272  for forming the outside of the storage case  1210  and a movable die  1274  for forming the inside of the storage case  1210 , as conceptually shown in  FIG. 42 . The holding rib  1254  and the sheet holding rib  1258  each having an undercut portion  1260  are formed by the use of a member interlocked with the movable die  1274 , such as a rib-molding core  1280  constructed of a projecting pin supported at one end on the ejector plate  1276  by the pivot shaft  1278  for pivotal movement. The rib-molding core  1280  is disposed to pivot with respect to the movable die  1274 , and oriented so that the direction of removal thereof lies in parallel with the surface of the sidewall  1242 . In addition, it is arranged to be urged by a spring, which is not shown, in the direction of removal of the rib-molding core  1280 , or to be pivoted by other actuators such as a motor, a fluid pressure cylinder, not shown, or the like, or preferably by its own weight, in the direction of removal in accordance with the movement of the movable die  1272 . The rib-molding core  1280  defines a seat  1262  with its tip surface  1280   a , and molds a holding rib by the recessed portion  1282  formed on the side surface  1280   b  facing upstream of the pivoting direction. As shown in  FIG. 42(   b ), the side surface  1280   c  facing downstream of the pivotal movement thereof is formed into a inclined surface, and as shown in  FIG. 42(   a ), the side surface  1280   d  at a right angle with respect to the side surface  1280   c  defines the back holder  1264 . 
     The magnetic tape cassette storage case  1210  is formed by injection molding in the state shown in  FIG. 43(   a ), in other words, in the state where the movable die  1272  is at the closest position to the fixed die  1274 . After the material such as synthetic resin is cured, as shown in  FIG. 43(   b ), the movable die  1272  is moved to open. At this moment, the storage case is still adhered to the movable die  1272 . 
     Then, the rib-molding core  1280  is pushed toward the releasing direction (left in  FIG. 43 ) by the ejector plate  1276 . Consequently, the rib-molding core  1280  that has been stored in the movable die  1272  and restricted from pivotal movement is now becomes pivotable in the hole  1273 . 
     Then, the rib-molding core  1280  is pivoted by a spring, which is not shown, or other actuators, or preferably by its own weight in the releasing direction (in the direction shown by the arrows in  FIG. 41  and  FIG. 43(   c )), so that the molded surface is separated from the holding rib  1254 . At this moment, the tip  1280   a  of the rib-molding core  1280  slides on the seat  1262  as shown in  FIG. 43(   c ), and when it is detached from the seat  1262 , it is completely separated from the top plate  1240 . Since there is formed a back holder  1264 , when the rib-molding core  1280  is pivoted and detached from the back holder  1264 , it is completely separated also from the sidewall  1242 . 
     Without the seat  1262  and the back holder  1264 , when the rib-molding core  1280  pivots, the tip portion  1280   a , especially on the side downstream of the pivotal movement, may be rubbed against the top plate  1240  and the sidewall  1242  at the corner  1280   e  (See  FIG. 4 ) on the side of the sidewall  1242  due to the contraction of the top plate  1240  and the sidewall  1242 . However, providing the seat  1262  and the back holder  1264  may prevent the top plate  1240  and the sidewall  1242  from being scratched by the corner  1280   e  of the rib-molding core  1280  when the rib-molding core  1280  pivots. 
     In the embodiment described above, the rib-molding core  1280  is mounted on the ejector plate  1276  to be also used as a pushing pin. However, it is also possible to provide it as a different member from the pushing pin, which cooperates with the movable die  1272 . 
     Though formation of the undercut portion  1260  of the holding rib  1254  is disclosed in the embodiment described above, it can be applied not only to the holding rib  1254 , but also to other undercut portions, as a matter of course. 
     Referring now to the attached drawings, the twenty-first embodiment of the present invention will be described. 
       FIG. 44  is a storage case for magnetic tape cassette according to the twenty-first embodiment of the present invention. The storage case  1310  comprises a storage section  1311  in which the magnetic tape cassette is stored, and a lid section  1321  connected to the storage section  1311  via the third plate portion  1320  and the thin portion  1319  constituting the connecting section. The storage section  1311  comprises a bottom plate  1312  of rectangular shape having a plurality of mounting projections  1317 ,  1318  on the inner surface thereof, and sidewalls  1313 ,  1313  and the end wall  1314  provided along the periphery of the bottom plate  1312  so as to extend upward for fitting the magnetic tape cassettes, not shown, therein. At the upper end and the outer surface of the sidewall  1313 , there are provided a positioning notch  1315  and a locking recess  1316  respectively. Also at the center of the outside of the end wall  1314 , there is provided a locking recess  1316 . 
     The lid section  1321  comprises a top plate  1322 , or the second plate portion connected to the plate portion  1320  for enabling the hinged movement, and a sidewalls  1323 ,  1323  and an end wall  1324 , or the second sidewall section, extending upwardly on the inner surface of the top plate and, for fitting along the outside of the sidewall  1313  and the end wall  1314  of the storage section  1311 . 
     Incidentally, in the broadcasting station or the like, it is important that information on the recorded contents in the magnetic tape cassette or the details of the meeting at the site of shooting can easily be recognized later, and thus in many cases, a strip of paper (hereinafter referred to as “information sheet”)P on which such information is listed is inserted into the clearance in the storage case. 
     In the storage case  10  shown in  FIG. 44 , the height of the sidewall  1323  and the end wall  1324  of the lid section  1321  and the width of the third plate portion  1320  corresponds with the sum of the thickness of the magnetic tape cassette and the thickness of the information sheet P in the stored state so that the information sheet P can easily be stored. Here, the height of the sidewall  1323  and the end wall  1324  and the width of the third plate portion  1320  is 20 mm (in the range of 15–30 mm). 
     The inner surface of the sidewall  1323  is formed with a positioning rib  1325  and a locking claw  1326  to be engaged with the positioning notch  1315  and the locking recess  1316  of the storage section  1311  respectively. The inner surface of the end wall  1324  is also formed with a locking claw  1326  at the center thereof. At both ends of the end wall  1324 , supporting ribs  1328  for supporting the magnetic tape cassette when the magnetic tape cassette is stored in the storage section  1311  and the lid section  1321  is closed are provided. The positioning rib  1325  and the supporting rib  1328  are in contact with the top plate  1322  at one end and extend along the sidewall  1323  and the end wall  1324  respectively to the height of 15 mm in this case (in the range of 10–20 mm). 
     The sidewall  1323  is provided with a sheet holding rib  1327  for holding the information sheet P on the inner surface. The sheet holding rib  1327  is in contact with the top plate  1322  at the proximal end and extends along the sidewall  1323 , and is provided with a holding claw  1327   b  for holding the end of the information sheet P at the distal end thereof. The upper surface of the holding claw  1327   b  is formed into a bevel  1327   a  for holding the magnetic tape cassette when the magnetic tape cassette is stored in the storage section  1311  and the lid section  1321  is closed. The sheet holding rib  1327  corresponds to the undercut portion when it is molded. 
     In the vicinity of the proximal portions of the positioning rib  1325  and the supporting rib  1328  on the top plate  1322  of the lid section  1321 , and in the vicinity of the position where the top plate  1322  and the vertical line running from the position where the locking claw  1326  is provided toward the top plate  1322  are intersected, there are formed pushed marks  1330  made by the ejector pins. Also in the vicinity of the proximal portion of the sheet holding rib  1327 , there is formed a pushed mark  1331  having the dimension along the sidewall  1323  or the end wall  1324  longer than the-pushed mark  1330 . 
       FIG. 45  shows a metal mold for magnetic tape cassette storage case. The metal mold  1340  comprises a main body of the metal mold, or the movable die  1341  for molding the inner side of the storage case, and a fixed die (not shown) for molding the outside of the storage case. The metal mold  1340  has a cavity for the locking claw  1326  on its side surface for molding the locking claw  1326 , which is an undercut portion, and an inclining pin  1343  that inclines inwardly of the storage case while pushing the molded article out of the movable die  1341  by the distal end surface. The proximal portion of the inclining pin  1343  is rotatably supported by the axis of rotation  1345 , which is provided on the ejector plate, not shown, and extending in parallel with the sidewall  1323 .  FIG. 45  shows the metal mold  1340  in the state before pushing operation, and at this time, a clearance S is formed between the distal end surface of the inclining pin  1343  and the molding surface of the movable die  1341 . The clearance S is 0.05–0.3 mm here. 
     The metal mold  1340  comprises a cavity for the sheet holding rib  1327  on its side surface for molding the sheet holding rib  1327 , which is an undercut portion, and an inclining pin  1344  that inclines in the direction along the sidewall  1323  while pushing the molded article out of the movable die  1341  by the distal end surface. The proximal end of the inclining pin  1344  is rotatably supported by the axis of rotation  1346 , which is provided on the ejector plate, not shown, and extending vertically with respect to the axis of rotation  1345 . Before pushing operation, as in the case of the inclining pin  1343 , a clearance is formed between the distal end surface of the inclining pin  1344  and the molding surface of the movable die  1341 . 
     Though it is not shown, the metal mold  1340  also comprises ejector pins for molding a positioning rib  1325 , a supporting rib  1328 , and a locking claw  1326  on the end wall  1324  shown in  FIG. 44 . There are also formed clearances between the distal end surfaces of these ejector pins and the molding surface of the movable die  1341  before pushing operation. 
     When synthetic resin is filled in the cavity of such a metal mold  1340 , a clearance between the distal end surfaces of the inclining pins  1343 ,  1344  and the movable die  1341 , and clearances between the distal end surfaces of the respective ejector pins for molding the positioning rib  1325 , the supporting rib  1328 , and the locking claw  1326  on the end wall  1324  and the molding surface of the movable die  1341  respectively serve as a gas vent. 
     Then, when the ejector plate, not shown, is driven and the storage case  1310 , or the molded article, is pushed by the inclining pins  1343 ,  1344  from the movable die  1341  from the state shown in  FIG. 45 , the inclining pin  1343  inclines inwardly of the storage case, or in the vertical direction with respect to the sidewall  1323 , and the inclining pin  1344  inclines in the direction along the sidewall  1323 . Then the locking claw  1326  and the sheet holding rib  1327  that are undercut portions respectively are released from the cavities on the side surface of the inclining pins  1343 ,  1344 . 
     In the metal mold  1340  for the storage case for magnetic case cassette constructed as described above, the positioning rib  1325 , the supporting rib  1328 , and the sheet holding rib  1327 , which are in contact with the top plate  1322  at one end and extending along the sidewall  1323  and the end wall  1324  respectively, are formed by the use of the ejector pin and the inclining pin  1344 , and the clearance between each pin and the movable die  1341  are used as a gas vent to ensure mold breathing. Therefore, the sidewall  1323  and the end wall  1324  are prevented from having bubbles trapped therein, thereby realizing molding of magnetic tape cassette storage case with preferable appearance. 
     Since the undercut portion for, for example, the locking claw  1326  are all molded by the inclining pin  1343  or the ejector pin and the clearance between each pin and the movable die  1341  is used as a gas vent, further preferable breathing can be performed. 
     In addition to the above-described twenty-first embodiment, it is also possible to use the metal mold of the present invention to form a magnetic tape cassette storage case in which the storage section is formed on its inner surface with a rib being in contact with the bottom plate and extending along the peripheral wall of at least 6 mm in height. 
     Alternatively, it is also possible to construct the metal mold in such a manner that the molded article stays in the fixed die and is pushed out by the ejector pin passing through the fixed die. 
     Though the present invention has been described according to some embodiments, the present invention also includes the combination of a plurality of such embodiments or modifications, as a matter of fact.