Patent Abstract:
The instant invention provides a recording tape cartridge in which there is no need for adjustment on the case side with respect to forces for holding and drawing-out a leader block. The tape cartridge comprises: a reel on which a recording tape is wound; a leader block attached to an end of the recording tape; a case for accommodating the reel; and a leader block receiving portion which is provided in the case and in which the leader block is received; wherein the leader block is elastically deformable and is capable of being held at the leader block receiving portion by an elastic restoring force of the leader block itself.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a recording tape cartridge which rotatably accommodates a single reel onto which a recording tape, such as a magnetic tape or the like, which is used as a recording/playback medium of a computer or the like, is wound. 
     2. Description of the Related Art 
     Conventionally, magnetic tape cartridges have been known in which a magnetic tape, which is used as a data recording/playback medium of a computer or the like, is wound on a single reel and the reel is accommodated within a plastic case. A leader member, such as a leader block or a leader pin, for example, is provided at a distal end (free end) of the magnetic tape. A drawing-out means, which is provided at a drive device, pulls out the leader member from the magnetic tape cartridge, so that the magnetic tape fixed to the leader member is wound onto a take-up reel of the drive device. 
     A reel gear is carved in an annular shape at a center of a bottom surface of the reel which emerges from an opening formed in a bottom surface of the magnetic tape cartridge. Due to a driving gear, which is provided at a rotating shaft of the drive device, meshing with the reel gear, the reel is driven to rotate. Further, due to the reel of the magnetic tape cartridge and the take-up reel of the drive device being rotated synchronously, writing and reading of information on the magnetic tape can be carried out. 
     Such magnetic tape cartridges have leader members provided at the distal ends of the magnetic tapes, as described above. In the case of a leader block  70 , as shown in  FIG. 5 , an opening  76  of the magnetic tape cartridge can be closed off by the leader block. The leader block  70  has an outer wall surface  72  which is outwardly exposed from the opening  76  and provided with a rear end portion  72 B. The leader block also has a front end portion  72 A and a concave portion  74  which is next to the front end portion and with which a drawing-out member  60  of a tape drive comes into engagement. By the rear end portion  72 B being hooked at a front end portion  82 B of a right wall of a case  80  and by the front end portion  72 A being hooked at a right end portion  82 A of a front wall of the case  80 , the leader block  70  can be retained so as to close off the opening  76 . 
     More specifically, the front wall right end portion  82 A of the case  80  has a slit  78  formed at an interior thereof by which the right end portion  82 A is elastically deformable in a front-back direction of the case  80 . Due to such an elastically deformable means formed on the case side, the leader block  70  can be detachably hooked and retained with respect to the case  80 . A force of the case  80  for holding the leader block  70  is sufficient to prevent the leader block  70  from easily falling from the case  80  even with the application of shocks due to dropping and the like. 
     Further, when the opening  76  is closed of by the leader block  70 , the magnetic tape T is pulled and held by a predetermined tension in a winding direction of a reel (not shown in the drawings) so as to prevent slack and the like which may occur within the case  80 . Therefore, when the leader block  70  is drawn out from the case  80  by the drawing-out member  60  of the tape drive side, some load is applied to the magnetic tape T, even though the reel is driven to rotate. Consequently, it is necessary that a force of the drawing-out member for drawing out the leader block  70  surpasses the load applied to the magnetic tape T and the holding force of the case  80  without the risk of elongation or breakage of the magnetic tape T. 
     Namely, it is necessary that the leader block  70  is suitably retained by the case  80  when the magnetic tape cartridge is not in use and that the leader block  70  is easily detachable from the case  80  when the magnetic cartridge is in use. Therefore, force-balancing between the drawing-out force exerted by the drawing-out member  60  and the holding force exerted by the case  80  must be appropriately maintained through delicate adjustment. Until now, such an adjustment has been effected by adjusting an elastically deformable means that is formed on the case side or by adjusting an elastic force of the front wall right end portion  82 A that is formed with the slit  78 . 
     Generally, cases of magnetic tape cartridges have a variety of mechanisms formed on outer surface portions thereof and are often subjected to modification and the like. If such a means for holding a leader block to a case is provided at the case side in this typical way, a degree of freedom of design of the case is adversely affected such that there are many more constraints on the case structure. Further, since the above-described force-balancing must be realized at the case side, the cost of manufacturing the cases is inevitably increased. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a recording tape cartridge that can eliminate the aforementioned problems of the prior art. 
     In order to achieve the object described above, according to a first aspect of the present invention, there is provided a tape cartridge which is insertable at a tape drive, the drive being provided with a drawing-out member which is operably engageable with the tape cartridge at a time of insertion of the tape cartridge and carrying out at least one of reading and writing of data, the tape cartridge comprising: a reel on which a recording tape is wound; a leader block attached to an end of the recording tape; a case for accommodating the reel; and a leader block receiving portion which is provided in the case and in which the leader block is received; wherein the leader block is elastically deformable and is capable of being held at the leader block receiving portion by an elastic restoring force of the leader block itself. 
     According to a second aspect of the present invention, there is provided a tape drive into which a tape cartridge is removably inserted and which can carry out at least one of reading and writing of data at a time of insertion of the tape cartridge, the tape drive comprising a drawing-out member for drawing-out a recording tape, the drawing-out member being operably engageable with the tape cartridge, wherein the tape cartridge comprises a reel on which the recording tape is wound, a leader block attached to an end of the recording tape, a case for accommodating the reel, and a leader block receiving portion which is provided in the case and in which the leader block is received, and wherein the leader block is elastically deformable and is capable of being held at the leader block receiving portion by an elastic restoring force of the leader block itself. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded schematic perspective view of a magnetic tape cartridge as seen obliquely from above. 
         FIG. 2  is a schematic perspective view showing a leader block according to the present invention. 
         FIGS. 3A ,  3 B, and  3 C are explanatory diagrams of a detaching operation of the leader block according to the present invention. 
         FIGS. 4A and 4B  are explanatory diagrams of an attaching operation of the leader block according to the present invention. 
         FIG. 5  is a schematic perspective view showing a conventional leader block and a drawing-out member of a drive device. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described in detail below on the basis of the drawings. For the sake of convenience of explanation, a direction of loading a recording tape cartridge into a drive device (the direction of arrow P in  FIG. 1 ) is referred to as a front direction, and other directions of back, left, right, top, and bottom will be specified on the basis of the front direction. Further, a magnetic tape is used as a recording tape, and hereinafter, explanation will be given with regard to a magnetic tape cartridge. 
     As shown in  FIG. 1 , a magnetic tape cartridge  10  is formed in the shape of a substantially rectangular box by an upper case  20  and a lower case  30 , which are each formed from a synthetic resin, being joined together by ultrasonic welding such that peripheral walls  22  and  32  thereof abut one another. A single reel  12 , on which a magnetic tape T serving as an information recording/playback medium is wound, is rotatably accommodated within the magnetic tape cartridge. Specifically, free play-restricting walls  24  and  34 , each being semi-cylindrical, are provided protruding at interior surfaces of the upper case  20  and the lower case  30 . The reel is accommodated inside the free play-restricting walls  24  and  34 . 
     A circular aperture  36  is formed at a center of the lower case  30 . A reel gear (not shown in the drawings), which is formed on a bottom surface of the reel  12  and has an annular shape, is exposed from the circular aperture  36 . The reel  12  is structured such that a cylindrical reel hub  14  and a bottom flange portion  18  radially projecting from a periphery of a bottom end of the reel hub  14  are integrally formed from a synthetic resin, and a top flange portion  16  having the same shape as the bottom flange portion  18  is joined by ultrasonic welding or the like to a top end of the reel hub  14 . Then, the magnetic tape T is wound around a peripheral surface of the reel hub  14 . 
     An opening  26  is formed at a front-right corner portion of the magnetic tape cartridge  10  by partially cutting away peripheral walls  22  and  32 . The opening  26  is for drawing out to an exterior of the magnetic tape cartridge  10  the magnetic tape T wound on the reel  12 . When the magnetic tape cartridge  10  is not in use, a leader block  40 , which is secured to a distal end of the magnetic tape T, is held at the front-right corner portion, thereby closing off the opening  26 . 
     A curved recess portion  48 , which is substantially semi-cylindrical in plan view, is formed at a front end of the leader block  40 . Recess portions  28  and  38 , which have substantially the same curvature as the curved recess portion  48 , are formed at locations of the upper case  20  and the lower case  30  in a vicinity of the opening  26 , which correspond to a location of the curved recess portion  48  of the leader block  40  when the opening  26  is closed off by the leader block  40 . As a result, a drawing-out member  60  (see  FIG. 5 ) of the drive device for drawing out the leader block  40  is easily insertable into the curved recess portion  48 . 
     That is, the leader block  40  is drawn out from the magnetic tape cartridge  10  by moving the drawing-out member  60 , which has been inserted and held in the curved recess portion  48 , to a take-up reel (not illustrated) of the drive device. Thereafter, the leader block is fitted into a fit-in portion (not illustrated) that is provided on a reel hub of the take-up reel of the drive device, so that the magnetic tape can be wound around the take-up reel of the drive device. 
     Next, detailed explanation will be given with regard to the leader block  40  and holding portions for holding thereof, of the upper case  20  and the lower case  30  in the magnetic tape cartridge described above. As shown in  FIGS. 1 through 4B , the leader block  40  is formed by deforming a plastic or metal, flat plate to the general shape of a “7”, as viewed from below. A longer first arm  42  and a shorter second arm  44  thereof are connected by a connection arm  46 . Due to elasticity of the connection arm  46 , the first arm  42  and the second arm  44  are elastically deformable in directions along which they move toward and away from one another (the directions being orthogonal to a heightwise direction of the magnetic tape cartridge  10 ). 
     That is, the leader block  40  comprises the first arm  42  having an outer wall surface  42 A which is exposed from the opening  26  when the leader block  40  is held by the upper case  20  and the lower case  30  so as to close the opening  26 , the second arm  44  which is disposed substantially parallel to the first arm  42  and has a length that is shorter than the first arm  42 , and the connection arm  46  which connects the first arm  42  and the second arm  44  and is formed in a circular-arc shape as seen in plan view. An outer wall portion  46 A of the connection arm  46  constitutes part of an outer peripheral surface of the reel hub of the take-up reel. 
     Further, the curved recess portion  48  is formed at a front end of the first arm  42 , is substantially semi-cylindrical in plan view, and engages the drawing-out member  60  of the drive device. The second arm  44  is provided with a recess portion  49  for securing the magnetic tape T, which recess portion  49  is formed in a circular-arc shape as seen in plan view. Specifically, a substantially columnar pin  50 , which is made of elastic material and has a diameter that is equal to or somewhat larger than a diameter of the recess portion  49 , is inserted into the recess portion  49  with the magnetic tape T tucked therein such that the leader block  40  is secured to the distal end (free end) of the magnetic tape T. 
     On the other hand, right wall portions of mutually joined peripheral walls  22 ,  32  of the upper case  20  and the lower case  30 , are integrally formed at front ends thereof with first holding portions  52  for holding a portion of the first arm  42  in the vicinity of a boundary of the connection arm  46 . Further, second holding portions  54  for holding a portion of the second arm  44  in the vicinity of another boundary of the connection arm  46  are integrally formed in a projecting manner, having a height less than or equal to a thickness of the bottom flange portion  18 , at predetermined positions on inside surfaces of the right wall portions of the upper case  20  and the lower case  30 . Side surfaces of the first and second holding portions  52  and  54  serve as abutment surfaces to the first and second arms  42  and  44 , respectively. Further, it is preferable to provide the second holding portions  54  continuously with an inner surface of the right wall, as illustrated, in consideration of the strength. 
     In plan view as shown in  FIGS. 3A-3C  and  4 A and  4 B, a distance (spacing) between the first holding portion  52  and the second holding portion  54  is somewhat shorter than a width of the connection arm  46  of the leader block  40  (i.e., the distance between an outer wall of the first arm  42  and an outer wall of the second arm  44 ). Accordingly, when the leader block  40  is inserted between the first holding portion  52  and the second holding portion  54  while being slightly pressed so as to oppose an elastic force of the connection arm  46 , in a direction in which the first arm  42  and the second arm  44  move toward one another, the leader block  40  is secured and held therebetween by the first arm  42  and the second arm  44  respectively pressing on the first holding portion  52  and the second holding portion  54  under a predetermined pressure based on restoring force of the connection arm  46 . 
     As described above, the height of each of the second holding portions  54  is less than or equal to a thickness of each of the flange portions  16  and  18  of the reel  12 , and a height of the leader block  40  is greater than a width of the magnetic tape T (see FIG.  2 ). As a result, there is no problem in that the magnetic tape would interfere with the second holding portions  54 . The leader block  40  is structured such that when the drawing-out member  60  of the drive device elastically deforms the connection arm  46  by pressing the first arm  42  toward the second arm  44  via the curved recess portion  48  to separate the first arm  42  from the first holding portion  52 , the leader block  40  can be detached from between the first holding portion  52  and the second holding portion  54 . 
     Load-balance between a holding force exerted by the upper case  20  and the lower case  30  and a pulling-out force exerted by the drawing-out member  60  can be maintained by adjusting an elastic force exerted by the connection arm  46 . More specifically, by appropriately establishing a (bending) force to be required at a time when the first arm  42  and the second arm  44  are bent toward one another, a holding force exerted by the upper case  20  and the lower case  30  can be adjusted, and, by appropriately establishing a (bending) force to be generated at a time when the first arm  42  and the second arm  44  are bent so as to move away from one another, a pulling-out force exerted by the drawing-out member  60  can be adjusted. 
     Detaching and attaching operations of the leader block will now be described. When the magnetic tape cartridge  10  is inserted into the drive device, the drawing-out member  60  of the drive device is firstly moved to engage the curved recess portion  48  of the leader block  40  which is hooked and held between the first holding portion  52  and the second holding portion  54  so as to close the opening  26  (see FIG.  3 A). Next, as shown in  FIG. 3B , the drawing-out member  60  presses and moves the curved recess portion  48  toward the second arm  44 , so that the first arm  42  moves toward the second arm  44 , while opposing an elastic (restoring) force of the connection arm  46 . 
     At that moment, the first arm  42  separates from the holding portion  52 . By maintaining this separated state and by moving the drawing-out member  60  toward the outside (in a direction in which the drawing-out member  60  departs from the opening  26 ), the second arm  44  can be separated from the second holding portion  54 , so that the leader block  40  is detached from between the first holding portion  52  and the second holding portion  54  (see FIG.  3 C). As described above, because the force to be required for detaching the leader block from the first and second holding portions via the drawing-out member  60  is appropriately adjusted by establishing an elastic force due to the connection arm  46 , problems such as tape breakage or the like can be prevented. 
     The leader block  40 , which has been drawn out through the opening  26  in the manner described above, is then mounted on the take-up reel of the tape drive. The drive device rotates the reel  12  and the take-up reel simultaneously and carries out recording of information onto the magnetic tape T and/or replaying of information that has been recorded on the magnetic tape T. 
     When the magnetic tape T has been wound back to the reel  12 , the leader block  40  is detached from the take-up reel and then disposed so as to again close off the opening  26 . Specifically, the leader block  40  is inserted through the opening  26  by the drawing-out member  60  which engages the curved recess portion  48 , so that the second arm  44  abuts the second holding portion  54 . Then, the first arm  42  is further pressed and moved toward the second arm by the drawing-out member  60  such that the connection arm  46  is bent and deformed (see FIG.  4 A). 
     Thereafter, as shown in  FIG. 4B , when the drawing-out member  60  is moved in the return direction and detached from the curved recess portion  48 , the first arm  42  is moved by a restoring force of the connection arm  46  in a direction in which it moves away from the second arm  44 , so that the first arm  42  abuts and presses the first holding portion  52  with a predetermined pressure. In other words, due to an elastic force (a restoring force) of the connection arm  46 , the first arm  42  and the second arm  44  press against the first holding portion  52  and the second holding portion  54 , respectively, with a predetermined pressure. 
     Consequently, the leader block  40  is again hooked and held between the first holding portion  52  and the second holding portion  54  such that the leader block  40  closes off the opening  26 . Because the holding force (i.e., the predetermined pressure mentioned above) for holding the leader block  40  to the upper case  20  and the lower case  30  is effectively ensured due to the elastic force of the connection arm  46 , the leader block  40  does not easily come apart from the opening  26  even with the application of shocks due to dropping and the like. 
     As described above, in the magnetic tape cartridge according to the present invention, an elastic, deformable means for holding and anchoring the leader block  40  is formed at the leader block rather than at the case. In other words, the leader block  40  has elasticity that allows deformation in a direction orthogonal to the heightwise direction of the magnetic tape cartridge  10 . Accordingly, if it is not possible to form such means at a case due to frequent design changes or the like, setting or adjustment of forces for holding and pulling-out the leader block  40  can be easily carried out on the leader block side. 
     Thus, for example, when the magnetic tape cartridge  10  is not in use, the leader block  40  is not easily and improperly removed from the opening  26 , whereas, when the magnetic tape cartridge is in use, there is no difficulty in removing the leader block  40  from the opening  26 . 
     In accordance with the present invention, even when case portions in the vicinity of the opening are subjected to improvements and the like, load-balance between a holding force and a pulling-out force with respect to the leader block can be easily maintained by simply adjusting the elastic force of the leader block itself.

Technology Classification (CPC): 6