Abstract:
A reel comprising: a hub on which a recording tape is wound; and a pair of flanges provided at both end portions of the hub respectively, and holding transverse direction end portions of the recording tape, wherein the hub is reinforced by a reinforcing ring, and at a time of release from a mold which molds the hub, an entire region of an end surface of the reinforcing ring is pushed, is provided.

Description:
[0001]    This application is a divisional application of U.S. application Ser. No. 11/877,265, filed Oct. 23, 2007, which claims priority to JP 2006-287444, filed Oct. 23, 2006, each of which is incorporated herein by reference in this entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a reel on which is wound a recording tape, such as a magnetic tape or the like, which is used as a recording/playback medium mainly of computers or the like. 
         [0004]    2. Related Art 
         [0005]    For example, recording tape cartridges, which accommodate within a case a reel on which a magnetic tape is wound, are known as external recording media of computers and the like. The reel has a hub, which structures the axially central portion of the reel and on whose outer periphery a magnetic tape is wound, and an upper flange and a lower flange, which project-out outwardly in the radial direction from the axial direction both ends of the hub respectively. 
         [0006]    There have conventionally been known recording tape cartridges in which a recording tape, such as a magnetic tape or the like 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 rotatably accommodated within a case made of a synthetic resin. A leader member, such as a leader pin, a leader tape, or a leader block, is provided at the distal end (free end) of the recording tape. A pull-out means provided at a drive device side pulls the leader member out from an opening of the recording tape cartridge, and winds the recording tape fixed thereto onto a take-up reel of the drive device side. 
         [0007]    At the reel of such a recording tape cartridge, the recording tape is usually wound on the outer peripheral surface of the hub. The upper flange and the lower flange are provided at the top and bottom of the hub respectively. The upper and lower flanges restrict the heightwise position of the recording tape in the vertical direction, hold the recording tape such that the wound posture thereof is good so as to improve the running stability, and further, prevent excessive damage at the time when the recording tape cartridge is not in use. 
         [0008]    On the other hand, it is often the case that the hub is formed in the shape of a cylindrical tube having a floor, in which one side in the axial direction is open and the other side is closed. At a hub which is formed in such a shape of the cylindrical tube having a floor, it is easy for the open end side thereof, which has low strength, to deform due to the winding pressure of the magnetic tape. In this way, if the hub deforms, the flange provided at the open end side of the hub deforms in a direction of contacting a transverse direction end portion (edge) of the magnetic tape. 
         [0009]    Therefore, structures have been thought of which reinforce the hub with a metal ring in order to prevent deformation of the hub, such as in Japanese Patent Applications Laid-Open (JP-A) Nos. 2004-14022 and 2005-116163 for example. In this way, if the outer peripheral surface of the metal ring is covered by resin and the metal ring and the resin are made integral by insert molding, because there is little heat shrinkage of the metal ring which is different than as is the case with resin, it is difficult for the molded product to bite-into the core side (the movable side), and the problem of so-called cavity removal defect arises. 
         [0010]    Therefore, the mold release resistance of the molded product from the core side is made to be higher than that at the cavity side, and the molded product is made to bite-into the core side. However, when releasing the molded product from the core side, the pushing force from ejecting pins which are for releasing the molded product becomes large by an amount corresponding to the amount by which the mold release resistance is made large. 
         [0011]    Further, there is the concern that, in the ejecting step, deformation or cracking of the metal ring will arise due to the concentration of stress at the metal ring which is due to the pushing of the ejecting pins. 
       SUMMARY 
       [0012]    In view of the aforementioned, an object of the present invention is to provide a reel in which the rigidity of a hub is improved and which can suppress the occurrence of deformation and cracking of the hub. 
         [0013]    In order to achieve the above object, a first aspect of the present invention is a reel having: a hub on which a recording tape is wound; and a pair of flanges provided at both end portions of the hub respectively, and holding transverse direction end portions of the recording tape, wherein the hub is reinforced by a reinforcing ring, and at a time of release from a mold which molds the hub, an entire region of an end surface of the reinforcing ring is pushed. 
         [0014]    In the first aspect, by reinforcing the hub by the reinforcing ring, the rigidity of the hub is improved. At the time of release from the mold which molds the hub, the entire region of the end surface of the reinforcing ring is pushed. In this way, large stresses are not applied locally at the end surface of the reinforcing ring, and the occurrence of deformation or cracking of the reinforcing ring is suppressed. 
         [0015]    As described above, in accordance with the present invention, the rigidity of the hub is improved, and further, the occurrence of deformation and cracking of the hub can be suppressed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    An exemplary embodiment of the present invention will be described in detail based on the following figures, wherein: 
           [0017]      FIG. 1A  is a schematic perspective view when viewing, from above, a recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0018]      FIG. 1B  is a schematic perspective view when viewing, from below, the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0019]      FIG. 2  is a schematic sectional view at the time when a reel of the recording tape cartridge relating to the exemplary embodiment of the present invention is at a rotation locked position; 
           [0020]      FIG. 3  is a schematic sectional view at the time when the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention is at a rotation permitted position; 
           [0021]      FIG. 4  is a schematic exploded perspective view when viewing, from above, the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0022]      FIG. 5  is a schematic exploded perspective view when viewing, from below, the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0023]      FIG. 6  is a schematic plan view of an upper flange and a reel hub of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0024]      FIG. 7  is a schematic bottom view of the upper flange and the reel hub of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0025]      FIG. 8  is a schematic plan view of a lower flange of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0026]      FIG. 9  is a schematic bottom view of the lower flange of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0027]      FIG. 10  is a schematic exploded sectional view of the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0028]      FIG. 11  is a schematic sectional view of the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0029]      FIG. 12  is a schematic sectional view showing a state in which a mold, which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention, is opened; 
           [0030]      FIG. 13  is a schematic sectional view showing a state in which the mold, which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention, is closed; 
           [0031]      FIG. 14  is a schematic sectional view showing a state in which the mold, which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention, is closed and resin is filled therein; 
           [0032]      FIG. 15  is a schematic sectional view showing a state in which the mold, which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention, is opened; 
           [0033]      FIG. 16  is a schematic sectional view showing a state in which the mold, which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention, is opened and a molded product is ejected; 
           [0034]      FIG. 17  is an explanatory diagram explaining a conventional problematic point; 
           [0035]      FIG. 18  is an explanatory diagram explaining a conventional problematic point; 
           [0036]      FIG. 19  is a schematic perspective view showing the molded product, and an ejecting sleeve of the mold which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0037]      FIG. 20  is a schematic perspective view corresponding to  FIG. 17  and showing the molded product which is molded in the mold which molds the reel hub and the upper flange of the recording tape cartridge relating to the exemplary embodiment of the present invention; 
           [0038]      FIG. 21  is a schematic exploded sectional view showing a first modified example of the structure of the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention; and 
           [0039]      FIG. 22  is a schematic exploded sectional view showing a second modified example of the structure of the reel of the recording tape cartridge relating to the exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0040]    A preferred form which embodies the present invention will be described in detail hereinafter on the basis of the exemplary embodiment shown in the drawings. First, the schematic structure of a recording tape cartridge  10  will be described. Note that, for convenience of explanation, the direction of loading the recording tape cartridge  10  into a drive device is denoted by arrow A, and this direction of arrow A is set to be the forward direction (front side) of the recording tape cartridge  10 . A direction orthogonal to the direction of arrow A is denoted by arrow B, and this direction of arrow B is set to be the rightward direction (right side) of the recording tape cartridge  10 . 
         [0041]    As shown in  FIG. 1  through  FIG. 3 , the recording tape cartridge  10  has a case  12 . The case  12  is structured by an upper case  14  and a lower case  16  being joined together. Specifically, the upper case  14  is structured such that a substantially frame-shaped peripheral wall  14 B stands erect along the outer edge of a ceiling plate  14 A which is substantially rectangular in plan view. The lower case  16  is structured such that a substantially frame-shaped peripheral wall  16 B stands erect along the outer edge of a floor plate  16 A which has a configuration substantially corresponding to that of the ceiling plate  14 A. The case  12  is formed substantially in the shape of a rectangular box by the upper case  14  and the lower case  16  being joined together by ultrasonic welding or screws or the like in a state in which the open end of the peripheral wall  14 B and the open end of the peripheral wall  16 B abut one another. 
         [0042]    At a corner portion of the case  12  at the leading side in the direction of loading the recording tape cartridge  10  into the drive device, the ceiling plate  14 A, the peripheral wall  14 B, the floor plate  16 A, and the peripheral wall  16 B are respectively cut-out such that an opening  18 , which is inclined with respect to the direction of loading, is formed. Further, a circular gear opening  20  which passes through the floor plate  16 A is provided in the substantially central portion of the floor plate  16 A, and is for exposing a reel gear  44  which will be described later. At the edge portion of the gear opening  20  at the floor plate  16 A, an annular rib  22  projects toward the inner side of the case  12 , and is for positioning a reel  30  which will be described later and for dust-proofing. 
         [0043]    A pair of positioning holes  24 ,  26  open in a vicinity of the front end of the outer surface of the floor plate  16 A of the case  12 . The pair of positioning holes  24 ,  26  are provided in the form of pockets within protruding portions (not shown) which stand erect from the floor plate  16 A toward the inner side of the case  12 . The positioning holes  24 ,  26  are disposed to be spaced apart from one another on an imaginary line in the direction of arrow B. The positioning hole  24 , which is at the side closer to the opening  18 , is formed, in bottom view, substantially in the shape of a square which circumscribes a positioning pin (not shown) of the drive device. The positioning hole  26  is formed as a long hole which is long along the aforementioned imaginary line and whose width corresponds to the diameter of a positioning pin. Accordingly, when the recording tape cartridge  10  is loaded into the drive device and positioning pins are inserted into the positioning holes  24 ,  26  respectively, the recording tape cartridge  10  is positioned accurately in the horizontal direction (the left/right direction and front/back direction) within the drive device. 
         [0044]    The portions of the floor plate  16 A around the positioning holes  24 ,  26  are reference surfaces  24 A,  26 A which are finished so as to be smoother than the other portions (the design surface) of the floor plate  16 A. When the positioning pins are inserted into the positioning holes  24 ,  26 , the reference surfaces  24 A,  26 A abut reference surfaces (not shown) of the drive device which are provided around the positioning pins. In this way, the vertical direction positioning of the recording tape cartridge  10  within the drive device is carried out. 
         [0045]    As shown in  FIG. 2  and  FIG. 3 , only one of the reel  30 , which will be described later, is rotatably accommodated in the case  12 . A recording tape T, such as a magnetic tape or the like, is wound on the reel  30 . As shown in  FIG. 1 , a leader block  28  serving as a leader member is attached to the distal end of the recording tape T. When the recording tape cartridge  10  is not being used, the leader block  28  is accommodated and held at the inner side of the opening  18  of the case  12 . In this state, the leader block  28  closes the opening  18  and impedes entry of dust and the like into the case  12 . 
         [0046]    An engaging recess  28 A is formed in the distal end of the leader block  28 . When the recording tape T is to be pulled-out within the drive device, the leader block  28  is taken-out from the case  12  by a pull-out means (not shown) which engages with the engaging recess  28 A, and is guided to a take-up reel (not shown) of the drive device. Moreover, the end surface of the leader block  28  at the side opposite the engaging recess  28 A is an arc-shaped surface  28 B. By being fit-into the reel hub of the take-up reel, the arc-shaped surface  28 B forms a portion of the take-up surface on which the recording tape T is taken-up. 
         [0047]    Next, the reel  30  and a braking means, which impedes rotation of the reel  30  when not in use, will be described. As shown in  FIG. 4  through  FIG. 7  and in  FIG. 10  and  FIG. 11 , the reel  30  has a reel hub  32  which structures the axially central portion thereof. The reel hub  32  has a cylindrical tube portion  34 , which has a wall thickness of 1.0 mm and around whose outer peripheral surface the recording tape T is wound, a metal ring (reinforcing ring)  112 , which is made of aluminum and has a wall thickness of 1.0 mm and is insert-molded at the inner peripheral surface of the cylindrical tube portion  34 , and an annular extending portion  36 , which is provided integrally at the bottom end portion of the cylindrical tube portion  34  so as to extend in an annular form by a predetermined width toward the center of the cylindrical tube portion  34 . Note that a width W (see  FIG. 7 ) of the annular extending portion  36  is an extent such that an engaging gear  48  and a standing rib  52 , which will be described later, can be formed. 
         [0048]    An annular concave portion  36 A serving as an engaged portion is formed to a predetermined depth at the bottom surface of the annular extending portion  36  and the central side of the reel hub  32 . Note that plural (three in the illustrated structure) expandingly-opening concave portions  36 B, whose surface areas open expandingly in circular-arc shapes in the radial direction, are formed so as to be separated from one another at predetermined intervals at the annular concave portion  36 A. Gates G, which are fill openings for a resin material of a mold (not shown) which molds the reel hub  32  and an upper flange  38 , are formed at the expandingly-opening concave portions  36 B. Further, the upper flange  38  is provided coaxially and integrally at the edge of the top end portion of the reel hub  32 , so as to extend toward the radial direction outer side. Namely, the reel hub  32  and the upper flange  38  are molded integrally from a resin material. 
         [0049]    On the other hand, a lower flange  40 , to which is fixed a reel plate  46  which is made of metal and will be described later, is joined (welded) to the bottom end portion of the reel hub  32 . As shown in  FIG. 4  and  FIG. 5  and  FIG. 8  through  FIG. 11 , the outer diameter of the lower flange  40  is the same as the outer diameter of the upper flange  38 . A floor wall  42 , which is substantially the same diameter as the reel hub  32 , is formed at the axially central portion of the lower flange  40 . 
         [0050]    An annular convex portion  42 A, which serves as an engaging portion which engages with the annular concave portion  36 A, is formed to a predetermined height at the top surface of the floor wall  42 . Plural (three in the illustrated structure) expandingly-opening convex portions  42 B, which fit-together with the expandingly-opening concave portions  36 B, are formed so as to be separated from one another at predetermined intervals at the annular convex portion  42 A. 
         [0051]    Further, as shown in  FIG. 8  through  FIG. 11 , plural (nine in the illustrated structure) energy directors (hereinafter called “EDs”)  41 , which are ribs for welding, project-out at uniform intervals at the top surface of the annular convex portion  42 A within a region where the reel plate  46  exists (between an outer peripheral edge portion  46 B and an inner peripheral edge portion  46 C). 
         [0052]    Accordingly, at the time of welding the lower flange  40  to the bottom surface of the annular extending portion  36  of the reel hub  32 , the expandingly-opening concave portions  36 B and the expandingly-opening convex portions  42 B are fit-together, and the annular concave portion  36 A and the annular convex portion  42 A are fit-together, and the EDs  41  are melted by ultrasonic waves generated from an unillustrated horn. 
         [0053]    In this way, the annular concave portion  36 A and the annular convex portion  42 A can be welded while the lower flange  40  (the reel gear  44  which will be described later) is positioned with respect to the reel hub  32 . The recording tape T can be wound around the outer peripheral surface of the cylindrical tube portion  34  of the reel hub  32  between the opposing surfaces of the upper flange  38  and the lower flange  40 . 
         [0054]    In this way, the EDs  41  are provided at the top surface of the annular convex portion  42 A within the region where the reel plate  46  exists. By interposing the metal reel plate  46  directly beneath the place where the reel hub  32  (the annular concave portion  36 A) and the lower flange  40  (the annular convex portion  42 A) are joined together (i.e., directly beneath the welded region), deformation due to tight-winding of the recording tape T can be suppressed at the reel plate  46 . 
         [0055]    Further, as shown in  FIG. 9 , the reel gear  44 , which is formed in an annular shape which is coaxial with the reel hub  32  at the time when the reel gear  44  is joined to the reel hub  32 , is formed at the bottom surface (outer surface) of the floor wall  42  at the lower flange  40 . The reel gear  44  can mesh-together with a driving gear  108  which is provided at the distal end of a rotating shaft  100  of the drive device shown in  FIG. 2  and  FIG. 3 . 
         [0056]    The tooth crests of the reel gear  44  project-out further downward than the bottom surface of the lower flange  40 , and the tooth bottoms are positioned further upward than the bottom surface of the lower flange  40 . The radial direction outer end portions of the respective teeth are connected by a taper portion  43  which is continuous with the lower flange  40  from the central portions in the heightwise direction of the teeth to the tooth bottoms thereof. A plurality (three in the illustrated structure) of the gates G, which are fill openings for a resin material of a mold (not shown) which molds the lower flange  40 , are formed at predetermined positions on the reel gear  44 . 
         [0057]    The reel plate  46 , which is an annular metal plate formed of a magnetic material, is fixed coaxially and integrally to the floor wall  42  of the lower flange  40  by insert molding, at the inner side of the reel gear  44 . Accordingly, plural (four in the illustrated structure) small holes  56 , which have step portions into which the resin material flows and stops, are formed in the reel plate  46 . 
         [0058]    A pass-through hole  50 , through which a clutch member  84  which will be described later is inserted, is formed in the center (the axially central portion) of the floor wall  42  at the lower flange  40 . A boss portion  54  for the clutch, which is shaped as a short cylindrical tube and serves as a guide wall portion, stands erect upwardly along the edge portion of the pass-through hole  50 . The boss portion  54  for the clutch will be described together with the clutch member  84  which will be described later. Note that the axially central portion of the reel plate  46  is a through-hole  46 A. As shown in  FIG. 10  and  FIG. 11 , the inner diameter of the through-hole  46 A is formed to be slightly smaller than the inner diameter of the pass-through hole  50 . 
         [0059]    As shown in  FIG. 6 , the engaging gear  48 , which is shaped as a ring which is coaxial with the reel hub  32 , is formed at the top surface of the annular extending portion  36  which is formed at the reel hub  32 . The engaging gear  48  can mesh-together with a braking gear  66  of a brake member  60  which will be described later. Plural (six in the illustrated structure) standing ribs  52 , which are continuous with the inner surface of the metal ring  112  and the top surface of the annular extending portion  36  along the axial direction of the reel  30 , are provided at uniform intervals in the peripheral direction at the radial direction outer side of the engaging gear  48 . Due to the existence of these standing ribs  52 , the engaging gear  48  is positioned further toward the radial direction inner side than the reel gear  44 . Note that the standing ribs  52  will be described later together with the brake member  60 . 
         [0060]    As shown in  FIG. 2  and  FIG. 3 , the reel  30  is accommodated in the case  12  and is placed on the annular rib  22  when not in use. Specifically, radial direction movement of the reel  30  is restricted due to the outer side portion of the taper portion  43  at the floor wall  42  abutting the top end surface of the annular rib  22 , and the inner edge portion of the upper end of the annular rib  22  being made to be a taper surface  22 A which corresponds to the taper portion  43 . This is a structure which deters entry of dust and the like therefrom. 
         [0061]    In this state, the reel  30  overall is positioned within the case  12 , and the reel gear  44  and the reel plate  46  are exposed from the gear opening  20  (see  FIG. 1B ). Namely, the reel gear  44  does not project-out from the outer surface (bottom surface) of the floor plate  16 A, but faces the exterior of the case  12  from the gear opening  20 . Further, the pass-through hole  50  faces the gear opening  20  through the through-hole  46 A of the reel plate  46 . 
         [0062]    In this way, operation of the reel  30 , i.e., chucking (holding) and driving/rotating, are possible from the exterior of the case  12 . Further, in this state, an annular restricting rib  58 , which stands erect from the ceiling plate  14 A, is disposed in the upper portion of the metal ring  112  of the reel  30 . The outer peripheral surface of the restricting rib  58  is adjacent to the inner peripheral surface of the metal ring  112  (the reel hub  32 ), such that the restricting rib  58  prevents joggling of the reel  30  within the case  12 . 
         [0063]    Further, the recording tape cartridge  10  has the brake member  60  which serves as a braking means which impedes rotation of the reel  30  at times when the recording tape cartridge  10  is not in use. The brake member  60  has a base portion  62 . The base portion  62  is formed substantially in the shape of a cylindrical tube having a floor which opens downward. A flat plate portion  64 , which is formed in an annular shape, extends outwardly in the radial direction over the entire periphery, from the axial direction intermediate portion of the outer peripheral portion of the base portion  62 . The braking gear  66  is provided over the entire periphery at the bottom surface of the flat plate portion  64 . Namely, the braking gear  66  is formed overall in an annular shape, and can mesh-together with the engaging gear  48  of the reel  30 . 
         [0064]    A sliding-contact projecting portion  68  projects-out at the axially central portion of the bottom surface of the base portion  62 . The distal end portion of the sliding-contact projecting portion  68  is formed to be substantially spherical, and substantially point-contacts the clutch member  84  which will be described later. On the other hand, a cross-shaped projection  70 , at whose interior is formed a groove which is substantially cross-shaped as seen in plan view, stands erect at the top surface of the base portion  62 . Further, an annular rib  72  stands erect at the top surface of the base portion  62 . The top surface of the base portion  62  between the rib  72  and the cross-shaped projection  70  is a spring receiving surface  74  which is abutted by one end portion of a compression coil spring  76  which will be described later. 
         [0065]    This brake member  60  is substantially coaxially inserted within the metal ring  112  of the reel hub  32 , so as to be movable in the vertical direction (the axial direction of the reel  30 ). Namely, due to the brake member  60  moving in the vertical direction, the brake member  60  can assume a position (rotation locked position), at which the braking gear  66  thereof meshes-together with the engaging gear  48  of the reel hub  32 , and a position (rotation permitted position) at which this meshing-together is released. 
         [0066]    A cross-shaped rib  80 , which projects downward from the ceiling plate  14 A of the case  12 , is disposed within the groove of the cross-shaped projection  70  of the brake member  60 . The cross-shaped rib  80  is shaped as a detent in which two thin plate pieces intersect one another orthogonally. Due to the cross-shaped rib  80  engaging with the groove walls of the cross-shaped projection  70 , rotation of the brake member  60  with respect to the case  12  is impeded. Accordingly, the brake member  60  can impede rotation of the reel  30 , in the state in which the braking gear  66  of the brake member  60  is meshed-together with the engaging gear  48  of the reel hub  32 . 
         [0067]    Note that the state in which the cross-shaped rib  80  is disposed within the groove is maintained over the entire vertical direction moving stroke of the brake member  60 , and the cross-shaped rib  80  also functions to guide the direction of movement of the brake member  60  in the vertical direction. Further, the brake member  60  is structured such that, when the brake member  60  is positioned at the rotation locked position, radial direction movement thereof is restricted by the standing rib  52  of the reel  30 , and, when the brake member  60  is positioned at the rotation permitted position, the brake member  60  does not interfere with the standing rib  52  which rotates together with the reel  30 . 
         [0068]    Namely, the upper portion of the standing rib  52  is cut-out such that the standing rib  52  is positioned adjacent to the outer peripheral edge of the flat plate portion  64  of the brake member  60  which is positioned at the rotation locked position, and such that an interval between the standing rib  52  and the brake member  60  which is positioned at the rotation permitted position becomes greater than or equal to a predetermined value. In this way, not only is movement of the reel  30  directly restricted by the case  12 , but also, in a vicinity of the position of the center of gravity thereof, radial direction movement of the reel  30  with respect to the case  12  is restricted via the brake member  60 . The recording tape cartridge  10  can be stably loaded even into the drive device which is disposed vertically (with the axis of the reel  30  being horizontal). 
         [0069]    The compression coil spring  76 , which can be interpreted in a broad sense as an urging means, is disposed between the ceiling plate  14 A and the spring receiving surface  74  of the brake member  60 . One end portion of the compression coil spring  76  abuts the spring receiving surface  74 , and the other end portion thereof abuts the ceiling plate  14 A. This other end portion is positioned at the inner side of an annular wall portion  78 , which projects-out at the ceiling plate  14 A at the outer side of the cross-shaped rib  80 , such that the position of this other end portion does not become offset in the radial direction. 
         [0070]    Due to the urging force of the compression coil spring  76 , the brake member  60  is urged downward, and usually causes the braking gear  66  to mesh-together with the engaging gear  48  and reliably prevents inadvertent rotation of the reel  30  (the brake member  60  is positioned at the rotation locked position). Further, due to this urging force, the reel  30 , which is meshed-together with the brake member  60  at the engaging gear  48 , also is urged downward and abuts the annular rib  22  so as to not joggle within the case  12 . 
         [0071]    The recording tape cartridge  10  has the clutch member  84  serving as a releasing member which is operated from the exterior when the locked state of the reel  30  by the brake member  60  is to be released. Accompanying the operation of the reel gear  44  meshing-together with the driving gear  108  of the drive device, the clutch member  84  is pushed by a releasing projection  110  of the drive device, which will be described later, so as to move upward, and is disposed between the floor wall  42  of the reel  30  and the brake member  60 . 
         [0072]    Namely, the clutch member  84  is substantially formed in the shape of a solid cylinder which is inserted through the through-hole  46 A and the pass-through hole  50 . The outer diameter of the clutch member  84  is slightly smaller than the inner diameter of the through-hole  46 A of the reel plate  46 , i.e., the pass-through hole  50  which coincides with the inner diameter of the boss portion  54  for the clutch. Further, the flat top end surface of the axially central portion of the clutch member  84  is a sliding-contact surface  86  which always abuts the sliding-contact projecting portion  68  of the brake member  60 . The flat bottom end surface of the clutch member  84 , which is around a lightening hole provided so as to open downward, is a pushing/operating surface  88 . Accordingly, when the pushing/operating surface  88  of the clutch member  84  is pushed, the clutch member  84  moves upward against the urging force of the compression coil spring  76 , and moves the brake member  60  to the rotation permitted position. 
         [0073]    Further, the clutch member  84  has rotation restricting ribs  90  which project-out further outwardly in the radial direction than the outer peripheral surface of the clutch member  84 . A plurality of (six in the present exemplary embodiment) the rotation restricting ribs  90  are provided at uniform intervals in the peripheral direction of the clutch member  84 , and are disposed radially as seen in plan view. The rotation restricting ribs  90  project-out further upward than the sliding-contact surface  86 , so as to be spread over (be continuous with) the top end surface of the clutch member  84  around the sliding-contact surface  86  and the outer peripheral surface in a vicinity of that top end surface. 
         [0074]    The rotation restricting ribs  90  are respectively disposed in rotation restricting grooves  82  (see  FIG. 4 ,  FIG. 8 ,  FIG. 10  and  FIG. 11 ) which are recessed in the inner edge portion of the boss portion  54  for the clutch. Namely, six of the rotation restricting grooves  82  are provided at uniform intervals in the peripheral direction of the boss portion  54  for the clutch, and open upward at the top end of the boss portion  54  for the clutch. In this way, the clutch member  84  can move in the vertical direction while, at the rotation restricting ribs  90  thereof, being guided by the rotation restricting grooves  82  of the boss portion  54  for the clutch. 
         [0075]    The rotation restricting ribs  90  maintain the state of being disposed in the rotation restricting grooves  82  of the boss portion  54  for the clutch, also when the clutch member  84  moves upward and positions the brake member  60  at the rotation permitted position. In this way, the clutch member  84  cannot rotate relative to the reel  30 , i.e., always rotates integrally with the reel  30 . Because the rotation restricting grooves  82  are closed at the lower end portion of the boss portion  54  for the clutch, the clutch member  84  is prevented from falling-out from the reel hub  32  by the rotation restricting ribs  90  and the rotation restricting grooves  82 . 
         [0076]    Note that, as shown in  FIG. 2  and  FIG. 3 , the rotating shaft  100  of the drive device has a rotating shaft portion  102 . A disc-shaped rotating table  104  extends integrally at the top end of the rotating shaft portion  102 . The driving gear  108 , which can mesh-together with the reel gear  44  of the recording tape cartridge  10 , is formed in an annular form at the top surface of and at the outer peripheral edge portion of the rotating table  104 . Further, a magnet  106 , which is substantially formed in the shape of a disc, is disposed coaxially at the top surface of the rotating table  104 , at the radial direction inner side of the driving gear  108 . The releasing projection  110 , which abuts the pushing/operating surface  88  of the clutch member  84 , is formed at the axially central portion of the rotating table  104 . 
         [0077]    Next, operation of the recording tape cartridge  10  having the reel  30  of the above-described structure will be described. At the recording tape cartridge  10 , when the recording tape cartridge  10  is not in use, due to the urging force of the compression coil spring  76 , the brake member  60  is positioned at the rotation locked position and causes the braking gear  66  to mesh-together with engaging gear  48 . Therefore, rotation of the reel  30  with respect to the case  12  is impeded. At this time, the reel gear  44  of the reel  30  is exposed from the gear opening  20 , and the clutch member  84  is inserted through the pass-through hole  50  and the through-hole  46 A and faces the gear opening  20 . 
         [0078]    On the other hand, when the recording tape T is to be used, the recording tape cartridge  10  is loaded along the direction of arrow A into a bucket (not shown) of the drive device. Then, when the recording tape cartridge  10  is loaded to a predetermined depth in the bucket, the bucket is lowered, and the rotating shaft  100  of the drive device relatively approaches the gear opening  20  of the case  12  (moves upward) and holds the reel  30 . Specifically, the rotating shaft  100  causes the driving gear  108  thereof to mesh together with the reel gear  44 , while attracting and holding the reel plate  46  by the magnet  106  in a non-contact state. 
         [0079]    Accompanying the meshing-together of the reel gear  44  and the driving gear  108 , i.e., the relative movement of the rotating shaft  100  with respect to the case  12  in the direction of approaching the case  12  along the axial direction, the releasing projection  110  of the rotating shaft  100  abuts the pushing/operating surface  88  of the clutch member  84 , and pushes the clutch member  84  upward against the urging force of the compression coil spring  76 . In this way, the brake member  60 , which is abutting the clutch member  84  at the sliding-contact projecting portion  68 , also moves upward, and the meshing-together of the braking gear  66  of the brake member  60  and the engaging gear  48  is released. 
         [0080]    Namely, the brake member  60  is moved to the rotation permitted position relative to the reel  30 . Thereafter, when the rotating shaft  100  further moves upward relatively, the reel  30  is brought upward together with the clutch member  84  and the brake member  60  (with their relative positions remaining unchanged) against the urging force of the compression coil spring  76 . The brake member  60  reaches the rotation permitted position (with respect to the case  12 ), and the lower flange  40  separates from the annular rib  22  (the taper surface  22 A). In this way, the reel  30  rises-up within the case  12 , and becomes able to rotate in a state of not contacting the inner surfaces of the case  12 . 
         [0081]    Further, at this time, due to the bucket, i.e., the recording tape cartridge  10 , being lowered within the drive device, the positioning pins of the drive device enter into the positioning holes  24 ,  26  of the case  12  respectively, and the reference surfaces of the drive device abut the reference surfaces  24 A,  26 A of the case  12 . In this way, the recording tape cartridge  10  is positioned in the horizontal direction and in the vertical direction with respect to the drive device. Thus, the pull-out means of the drive device, while engaging with the engaging recess  28 A of the leader block  28 , takes the leader block  28  out from the case  12  and guides the leader block  28  to the take-up reel of the drive device. 
         [0082]    Then, the leader block  28  is fit into the reel hub of the take-up reel such that the arc-shaped surface  28 B thereof forms a portion of the take-up surface around which the recording tape T is taken-up. In this state, when the leader block  28  rotates integrally with the take-up reel, the recording tape T is pulled-out from the case  12  through the opening  18 , while being taken-up onto the reel hub of the take-up reel. Note that, at this time, the reel  30  of the recording tape cartridge  10  rotates synchronously with the take-up reel due to the rotational force of the rotating shaft  100  which is transmitted by the driving gear  108  which is meshed-together with the reel gear  44 . 
         [0083]    Then, recording of information onto the recording tape T, or playback of information recorded on the recording tape T, is carried out by a recording/playback head (not shown) which is disposed along a predetermined tape path of the drive device. Note that, at this time, the sliding-contact projecting portion  68  of the brake member  60 , which cannot rotate with respect to the case  12 , slidingly-contacts the sliding-contact surface  86  of the clutch member  84  which rotates together with the reel  30  with respect to the case  12 . Namely, the clutch member  84  is structured such that, in the state in which the reel gear  44  is meshed-together with the driving gear  108 , the state of abutment of the clutch member  84  with the releasing projection  110  at the pushing/operating surface  88  of the clutch member  84  is maintained, and the clutch member  84  holds the brake member  60  at the rotation permitted position. 
         [0084]    Then, when the reel  30  rotates, there is no relative rotation between the clutch member  84 , which rotates integrally with the reel  30 , and the rotating shaft  100 , which drives the reel  30 , and the pushing/operating surface  88  and the releasing projection  110  do not slidingly-contact one another. The sliding-contact surface  86  of the clutch member  84  and the sliding-contact projecting portion  68  of the brake member  60 , which cannot rotate with respect to the case  12 , slidingly-contact one another. In this way, because there is no relative rotation between the rotating shaft portion  102  and the clutch member  84 , the problem of the releasing projection  110  or the pushing/operating surface  88  becoming worn does not arise. 
         [0085]    On the other hand, when the recording of information onto the recording tape T or the playback of information recorded on the recording tape T is finished, the recording tape T is rewound onto the reel  30 , and the leader block  28  is held in a vicinity of the opening  18  of the case  12 . Then, the bucket in which the recording tape cartridge  10  is loaded rises. Thus, the meshing-together of the reel gear  44  and the driving gear  108  is released, the abutment of the releasing projection  110  and the pushing/operating surface  88  of the clutch member  84  is released, and the clutch member  84  moves downward together with the brake member  60  (with the state of abutment thereof maintained) due to the urging force of the compression coil spring  76 . 
         [0086]    In this way, the braking gear  66  of the brake member  60  meshes-together with the engaging gear  48 , and the brake member  60  returns to the rotating locked position at which the brake member  60  impedes rotation of the reel  30  with respect to the case  12 . Further, accompanying the operation of the brake member  60  and the clutch member  84  moving due to the urging force of the compression coil spring  76 , the reel  30  also moves downward. While the lower flange  40  of the reel  30  is made to abut the annular rib  22 , the reel gear  44  is returned to its initial state of being exposed from the gear opening  20 . In this state, the recording tape cartridge  10  is ejected from the drive device (bucket). 
         [0087]    The structure of the mold which molds the reel relating to the exemplary embodiment of the present invention will be described next. 
         [0088]    As shown in  FIG. 12  through  FIG. 16 , a mold  116  is broadly divided into a fixed side  118  and a movable side  120 . A movable side mold plate  122 , ejecting plates  124 ,  126 , and a movable side attachment plate  128  are provided at the movable side  120 . A fixed side mold plate  130  and a fixed side attachment plate (not shown) are provided at the fixed side  118 . Opening or closing of the mold  116  is carried out by the movable side  120  moving horizontally with respect to the fixed side  118  by an unillustrated driving means. 
         [0089]    A concave portion  130 A or a convex portion  122 A is formed at the surface of the fixed side mold plate  130  or the movable side mold plate  122 . First, in the state in which the mold  116  is opened as shown in  FIG. 12 , the metal ring  112  is made to engage with the convex portion  122 A of the movable side mold plate  122 . Then, in the state in which the mold  116  is closed as shown in  FIG. 13 , resin is filled through the gate G, which is provided at the fixed side mold plate  130 , into a space  132  which is formed by the fixed side mold plate  130  and the movable side mold plate  122  as shown in  FIG. 14 . Due to solidification of this resin, the reel hub  32  and the upper flange  38  (hereinafter called “molded product  138 ”) are molded. 
         [0090]    On the other hand, the ejecting plates  124 ,  126  are disposed between the movable side mold plate  122  and the movable side attachment plate  128 . An attachment portion  136 A of an annular ejecting sleeve  136  is attached to the ejecting plates  124 ,  126 . In the state in which the mold  116  is closed, the distal end surface of the ejecting sleeve  136  abuts the entire region of the end surface of the metal ring  112 . Further, an insert-through hole  140 , which is annular and through which the ejecting sleeve  136  can be inserted, is formed in the movable side mold plate  122 , and the ejecting sleeve  136  can move within the movable side mold plate  122 . 
         [0091]    In the state in which resin has been filled within the space  132  and has become solidified, when the mold  116  is opened as shown in  FIG. 15 , the molded product  138  is released from the fixed side mold plate  130 , and moves integrally with the movable side mold plate  122 . 
         [0092]    Then, as shown in  FIG. 16 , the ejecting plates  124 ,  126  are pushed by an ejecting rod  142  which is movably provided at the movable side mold plate  122 . In this way, the ejecting plates  124 ,  126  move within the gap provided between the ejecting plate  124  and the movable side mold plate  122 , the ejecting sleeve  136  moves within the insert-through hole  140  of the movable side mold plate  122 , the distal end surface of the ejecting sleeve  136  pushes the entire region of the end surface of the metal ring  112  and ejects the molded product  138 , and releases the molded product  138  from the movable side mold plate  122 . Note that, other than the ejecting sleeve  136 , there is an ejecting pin which abuts the molded product  138  and ejects the molded product  138 , but description thereof will be omitted here. 
         [0093]    In a case of carrying out insert molding by the metal ring  112 , because there is little heat shrinkage at the metal ring  112  which is different than as is the case with resin, it is difficult of the molded product  138  to bite-into the movable side mold plate  122 . In the state shown in  FIG. 15  in which the mold  116  is opened, there are cases in which the molded product  138  remains at the fixed side mold plate  130  (so-called cavity removal defect). 
         [0094]    Therefore, the mold release resistance of the molded product  138  from the movable side mold plate  122  is made to be higher than that of the fixed side mold plate  130 , and the molded product  138  is made to bite-into the movable side mold plate  122 . However, when the molded product  138  is to be released from the movable side mold plate  122 , the pushing force by ejecting pins  150  (see  FIG. 17 ), which are for causing the molded product  138  to be released, becomes large by an amount corresponding to the amount by which the mold release resistance is made large. Large stresses are applied locally to the end surface of the metal ring  112 , and, as shown in  FIG. 18 , there is the concern that deformation or cracking of the metal ring  112  will arise. 
         [0095]    However, in accordance with the present exemplary embodiment, at the time of releasing the molded product  138 , as shown in  FIG. 16  and  FIG. 19  (in  FIG. 19 , in order to illustrate the shape of the ejecting sleeve  136 , a gap is provided between the distal end surface of the ejecting sleeve  136  and the end surface of the metal ring  112 ), the entire region of the end surface of the metal ring  112  (the region shown by hatching in  FIG. 20 ) is pushed by the annular ejecting sleeve  136 . In this way, pushing force is applied uniformly at the entire region of the end surface of the metal ring  112 , and the occurrence of deformation or cracking of the metal ring  112  is suppressed. 
         [0096]    Note that, here, the entire region of the end surface of the metal ring  112  is pushed by the ejecting sleeve  136 . However, if a resin layer is provided at the end surface of the metal ring  112 , the entire region of the end surface of this resin layer is pushed by the ejecting sleeve  136 . 
         [0097]    Further, the material and wall-thickness of the metal ring  112  are not limited to those described in the present exemplary embodiment, and the reinforcing ring may be a non-metal material provided that it increases the rigidity of the reel hub  32 . However, if a corrosive material such as an aluminum material or the like is used for the reinforcing ring, it is desirable that the surface of the reinforcing ring be subjected to a corrosion preventing treatment such as plating or the like. 
         [0098]    It is desirable that the aluminum material have sufficient proof stress in order for setting to not arise with respect to tight-winding of the recording tape T. In the case of the present exemplary embodiment, an aluminum material having a proof stress of 350 N/mm 2  is used. Further, the material of the cylindrical tube portion  34  is not limited to polycarbonate (PC) and may be another resin material which can be injection molded, provided that mechanical strength which satisfies the specifications of the reel  30  can be obtained. 
         [0099]    Further, in the present exemplary embodiment, as shown in  FIG. 10 , the reel hub  32  and the upper flange  38  are molded integrally, and the reel gear  44 , which meshes-together with the driving gear  108  of the drive device, is provided at the lower flange  40 . However, the reel gear  44  may be provided at the reel hub  32 , although such a structure is not illustrated. 
         [0100]    Moreover, as shown in  FIG. 21 , a structure in which the reel hub  32  and the lower flange  40  are molded integrally may be used. Or, the upper flange  38 , the reel hub  32 , and the lower flange  40  may be structured by three parts (three pieces) as shown in  FIG. 22 . 
         [0101]    Here, as shown in  FIG. 2 , the through-hole  46 A is formed for movement of the clutch member  84 . However, in a type of recording tape cartridge in which the through-hole  46 A is not formed, the position of the gate of the mold can be made to be the central portion of the reel hub  32 , although such a structure is not illustrated. In this way, because the resin is filled into the mold by spreading radially with the gate as the center, it is difficult for weld lines (seams of the resin) or the like to arise, and the strength of the reel  30  can be improved. 
         [0102]    Note that in the recording tape cartridge  10  of the above-described exemplary embodiment, the leader block  28  is used as the leader member. However, the recording tape cartridge  10  is not limited to the above-described exemplary embodiment. For example, the recording tape cartridge  10  may be a structure having a solid-cylindrical leader pin (not shown) as the leader member, or may be a structure having a covering member which opens and closes the opening  18  (a sliding door or the like (not shown) which moves along a predetermined straight line or circular arc). Moreover, it suffices for the recording tape T to be interpreted as an elongated-tape-shaped information recording/playback medium onto which information can be recorded and from which recorded information can be played-back. It goes without saying that the recording tape cartridge  10  (the reel  30 ) can be applied as well to recording tapes T of any recording/playback systems. 
         [0103]    The above-described exemplary embodiment illustrates an example in which the reel  30  is applied to the recording tape cartridge  10  which is structured so as to accommodated a single reel within the case  12 . However, the present invention is not limited to the same, and the reel  30  may be applied, for example, to a two-reel recording tape cartridge which accommodates two reels within a case.