Tape reel

The tape reel of the present invention includes: a cylindrical hub for winding recording tape; and a pair of upper and lower flanges respectively projecting circumferentially from upper and lower portions of the hub. The tape reel further comprises: a lower piece including the lower flange and a first cylinder wall formed integrally with the lower flange; and an upper piece including the upper flange and a second cylinder wall formed integrally with the upper flange. The hub is formed in a double cylinder form by a fit engagement between the first cylinder wall of the lower piece and the second cylinder wall of the upper piece.

FIELD OF THE INVENTION

The present invention relates to a tape reel including a cylindrical hub for winding recording tape and a pair of upper and lower flanges respectively projecting circumferentially from an upper portion and a lower portion of the hub.

DESCRIPTION OF RELATED ART

The problems of this type of tape reel include preventing the reel from being tightened by the recording tape when winding the tape. That is, when a large tape winding force is applied to the hub, a cylinder wall of the hub deforms inwardly.

Conventional measures for preventing the reel from being tightened by winding tape include increasing the wall thickness of the hub cylinder wall, selecting a material to be used for the hub cylinder wall, and the like. For example, in Patent document 1, the rigidity of the hub is enhanced by providing the hub with an annular space portion whose lower side is open, and filling the space portion with a synthetic resin using coinjection molding. According to this configuration, since a compressive deformation stress in the direction toward the center of the hub can be increased, even if a large tape winding force is applied to the hub cylinder wall in a high temperature, the upper end portion of the hub cylinder wall can be surely prevented from deforming inwardly.

In Patent document 2, a notch having an upwardly stepped receiving surface is formed in a circle between the upper end surface and the inner side surface of a hub cylinder wall that is integrally molded with a lower flange. By mounting on the notch an annular reinforcing member that is received by the receiving surface, the upper end of the hub cylinder wall is prevented from deforming inwardly.

In Patent document 3, a downwardly-extending circular boss is provided on the rim of an opening formed at the center of an upper flange, and the deformation of the hub is prevented by receiving the circular boss with an inner peripheral surface of the upper end of the hub cylinder wall.

Patent document 4 proposes a reel including: a first member formed integrally with a first flange on one end side of a hub in its axis direction; and a second member formed integrally with a second flange and a fixing portion fixed to the first member other than the hub (see claim 1 of Patent document 4).

With this configuration, since the second flange (second member) is not fixed to the opening end of the hub, in other words, since deformation of the hub does not transfer to the second flange, the second flange is prevented or inhibited from being displaced toward the recording tape side or from deforming due to the deformation of the hub, which is caused by a winding pressure of the recording tape.

In contrast, the first flange is prevented from being displaced toward the recording tape side or from deforming, for example, by enhancing the rigidity of the hub (there are only few constraints in enhancing the rigidity of the hub to which the second member is not fixed) and setting the strength of the hub against the winding pressure lower on the first flange side than on the other end side (paragraph 0009 of Patent document 4).

However, each configuration for preventing the reel from being tightened by winding the tape as described above has the following problem.

When the rigidity of the hub is enhanced by increasing the wall thickness of the hub cylinder wall, a problem relating to molding occurs. That is, since the wall thickness of the hub cylinder wall becomes unavoidably larger than that of the flanges, the wall thicknesses of the hub and the flanges become different, and unsightly sink marks (dents) appear on the surface of the thickened portion.

In a case where the hub is made of a material containing a glass filler, the manufacturing cost of the tape reel including the hub increases, which results in an increase in the product unit price. Further, mixing of a glass filler is a significant burden on a molding machine and a mold, and this also results in an increase in the product unit price.

In the reel described in Patent document 1, the hub is prevented from deforming by providing a reinforced portion in the hub using coinjection molding to enhance the rigidity of the hub. However, the number of manufacturing steps increases by performing the coinjection molding, which results in an increase of the manufacturing cost of the tape reel.

A tape reel provided with an annular reinforcing member as in Patent document 2 has a complex structure. Further, the number of parts increases by providing the reinforcing member, which results in an increase in the manufacturing cost of the tape reel.

In the tape reel described in Patent document 3, deformation of the hub cylinder wall is merely prevented by the circular boss with a small wall thickness. Thus, when a strong tape winding force is applied to the hub in a high temperature, the possibility of the upper end portion of the hub cylinder wall deforming inwardly still remains.

The tape reel described in Patent document 4 has a configuration in which the hub is purposefully tilted inwardly so as to prevent the upper and the lower flanges from coming into contact with the magnetic tape. This configuration, however, is not for preventing the deformation of the hub.

The present invention is to solve the problems of the conventional tape reels, and an object of the present invention is to provide a tape reel in which a hub is prevented from being tilted inwardly by enhancing the rigidity of the hub with a simple configuration.

Patent document 1: JP H7-320447 A

Patent document 2: JP 2005-78784 A

Patent document 3: JP 2003-7030 A

Patent document 4: JP 2006-92611 A

SUMMARY OF THE INVENTION

In order to achieve the above object, the tape reel of the present invention includes: a cylindrical hub for winding recording tape; and a pair of upper and lower flanges respectively projecting circumferentially from upper and lower portions of the hub. The tape reel further comprises: a lower piece including the lower flange and a first cylinder wall formed integrally with the lower flange; and an upper piece including the upper flange and a second cylinder wall formed integrally with the upper flange. The hub is formed in a double cylinder form by a fit engagement between the first cylinder wall of the lower piece and the second cylinder wall of the upper piece.

DETAILED DESCRIPTION OF THE INVENTION

In the tape reel of the present invention, the cylinder walls that are respectively molded integrally with the upper and the lower flanges are provided respectively on the upper and the lower pieces, and the hub is formed in a double cylinder form by a fit engagement between both cylinder walls. Thus, the rigidity of the hub can be enhanced by increasing the thickness of the entire hub without increasing the wall thickness of the cylinder wall in each piece.

Thus, since the upper end portion of the hub is prevented from deforming inwardly due to being tightened by a winding force of the recording tape, it is possible to prevent one side of the recording tape from being stretched. Further, since a precise driving height of the recording tape can be ensured favorably, it is possible to prevent the occurrence of defective performances such as recording and reproduction errors. Accordingly, it is possible to improve the reliability of a tape cartridge into which the tape reel of the present invention is incorporated.

Further, it is not necessary to increase the wall thickness of the cylinder wall of each piece. As a result, the thicknesses of the flanges and the cylinder walls can be easily made uniform as much as possible, and the occurrence of sink marks can be prevented effectively.

Therefore, since it is not necessary to include a glass filler and the like in the molding material for the cylinder walls, an increase in the product unit price can be prevented and a burden on a molding machine and a mold can be reduced. Also in this regard, it is possible to prevent an increase in the product unit price.

In the tape reel of the present invention, it is preferable that a structure of the double cylinder form is for preventing the hub from deforming inwardly when winding the recording tape around the hub. According to this configuration, it is possible to prevent one side of the recording tape from being stretched and to ensure the precise driving height of the recording tape favorably.

Further, in the first cylinder wall and the second cylinder wall that form the hub, it is preferable that an inner cylinder wall has a height that is ½ or more of that of an outer cylinder wall. According to this configuration, part of the outer cylinder wall from the upper end portion to the center of the outer cylindrical wall in the height direction where deformation due to being tightened by winding the recording tape is likely to occur can be supported by the inner cylinder wall from the back side.

Further, it is preferable that at a portion where the first cylinder wall and the second cylinder wall are in a fit engagement, it is preferable that a surface of the first cylinder wall and that of the second cylinder wall overlap with one other. According to this configuration, it is advantageous for preventing the hub from deforming inwardly.

Further, it is preferable that the lower piece forms a cylindrical body with a bottom composed of a hub bottom wall and the first cylinder wall, in the inside of the cylindrical body with a bottom, a mounting groove is formed on an outer peripheral portion of the hub bottom wall, and an end portion of the second cylinder wall of the upper piece is fitted into and is in engagement with the mounting groove. According to this configuration, it is possible to prevent the lower end portion of the second cylinder wall from being suspended, and it is also possible to prevent the second cylinder wall from being suspended along the first cylinder wall.

Further, it is preferable that the fit engagement between the first cylinder wall and the second cylinder wall is an interference fit. According to this configuration, a compression stress is applied to the inner cylinder wall due to a pressure by the outer cylinder wall, so that the opposing wall surfaces of the inner cylinder wall and the outer cylinder wall can be firmly brought into intimate contact. In this state, the hub has a virtual laminate structure, which is advantageous for enhancing the rigidity of the hub.

Further, it is preferable that a portion that is in the interference fit is ½ or more of a height of the outer cylinder wall in the first and the second cylinder walls that form the hub. According to this configuration, an effect of enhancing the rigidity by the interference fit can be exerted easily.

Further, it is preferable that in the first and the second cylinder walls that forms the hub, an inner cylinder wall includes a notch, and a portion on which the notch is formed is in a single cylinder form. According to this configuration, even when the locking mechanism is housed in the cylindrical portion, the thickness of the inner cylinder wall can be ensured while maintaining the outer dimensions of the outer cylinder wall. Thus, a highly rigid double wall structure can be achieved.

Hereinafter, one example of the present invention will be described in detail with reference to the drawings.

FIG. 1is an exploded perspective view showing a tape reel according to one embodiment of the present invention. As shown in the figure, a tape reel1includes a lower piece10and an upper piece20that are molded separately.

The lower piece10is a molded product made of plastic, and is composed of a cylindrical body17and a disc-shaped lower flange14formed integrally with the cylindrical body17and projecting from the outer periphery of the lower end of the cylindrical body17. The cylindrical body17is in the form of a cylinder having a bottom and an upper opening12, and is composed of a hub bottom wall11and an outer cylinder wall13.

The upper piece20is a molded product made of plastic, and is composed of an inner cylinder wall21and a disc-shaped upper flange22formed so as to project from the upper end of the inner cylinder wall21.

FIG. 2is a cross-sectional view showing a state in which the lower piece10and the upper piece20are coupled. The inner cylinder wall21of the upper piece20is fitted in the outer cylinder wall13of the lower piece10. Drive teeth15with which a drive shaft of a tape drive engages are formed on the lower surface of the hub bottom wall11of the lower piece10.

FIG. 3is an enlarged view of the portion A inFIG. 2. In the inside of the outer cylinder wall13of the lower piece10, a mounting groove16is formed on an outer peripheral portion of the hub bottom wall11. The mounting groove16is a concave portion that is formed in a circle. A lower end portion21aof the inner cylinder wall21of the upper piece20is fitted into and is in engagement with the mounting groove16.

As shown inFIG. 3, the outer cylinder wall13of the lower piece10is tapered, and its wall thickness gradually and slightly decreases in the upward direction.

When coupling the lower piece10and the upper piece20, the inner cylinder wall21of the upper piece20is dropped into the outer cylinder wall13from the upper opening12side of the lower piece10. Then, the inner cylinder wall21of the upper piece20is fitted into the outer cylinder wall13by pressing the inner cylindrical wall21into the outer cylindrical wall13until the lower end portion21aof the inner cylinder wall21is fitted into and engages with the mounting groove16, and an upper end13aof the outer cylinder wall13is received by the back surface of the upper flange22.

Through the above procedure, the reel1is completed. As shown inFIGS. 2 and 3, in this complete state, a hub5with a double cylinder form is formed by a fit engagement between the outer cylinder wall13of the lower piece10and the inner cylinder wall21of the upper piece20, and the lower piece10and the upper piece20are coupled together.

FIG. 4is a plan view showing a tape cartridge according to the present embodiment. The figure shows an example in which the tape reel1shown inFIG. 2is applied to a single reel tape cartridge. In a tape cartridge2, one tape reel is disposed in a case body3. The case body3has a four-sided box shape and is formed by the engagement between upper and lower plastic cases. Recording tape4on which information signals are recorded is wound around the outer surface of the hub5of the tape reel1.

Hereinafter, the tape reel1according to the present embodiment will be described in more detail. As described above, the outer cylinder wall13of the lower piece10and the inner cylinder wall21of the upper piece20are in a fit engagement (seeFIGS. 2 and 3). The fit engagement may be an interference fit. In this case, as shown inFIG. 1, the outer diameter of the inner cylinder wall21of the upper piece20is set slightly larger than the inner diameter of the outer cylinder wall13of the lower piece10before coupling the lower piece10and the upper piece20.

According to this setting, in the coupled state where the inner cylinder wall21is completely inserted in the outer cylindrical wall13as shown inFIGS. 2 and 3, against a force that makes the inner cylinder wall21expand in the outward direction, a reactive force that makes the inner cylinder wall21shrink in the inward direction is applied to the inner cylinder wall21from the outer cylinder wall13. As a result, a compressive stress is applied to the inner cylinder wall21due to a pressure by the outer cylinder wall13. That is, in the coupled state as shown inFIGS. 2 and 3, the inner cylinder wall21and the outer cylinder wall13are in a fit engagement by interference fit.

In the present embodiment, the rigidity of the hub5is enhanced by forming the hub5in a double cylinder form. Thus, for example, even if a large winding force is applied to the hub5in a high temperature, it is possible to counteract the winding force of the recording tape4. Thus, it is possible to prevent the hub5from deforming inwardly.

Further, the outer cylinder wall13of the lower piece10and the inner cylinder wall21of the upper piece20can be in a fit engagement by placing one surface on the other. This is also advantageous for preventing the hub5from deforming inwardly.

Further, when the outer cylinder wall13of the lower piece10and the inner cylinder wall21of the upper piece20are in a fit engagement by an interference fit, a compression stress is applied to the inner cylinder wall21due to a pressure by the outer cylinder wall13as described above, so that the opposing wall surfaces of the inner cylinder wall21and the outer cylinder wall13can be firmly brought into intimate contact. In this state, the hub5has a virtual laminate structure, which is advantageous for enhancing the rigidity of the hub5. Therefore, the hub5displays excellent winding drag, which is further advantageous for preventing the hub5from deforming inwardly.

It should be noted that although the outer cylinder wall13and the inner cylinder wall21may be entirely in an interference fit, they may be partially in an interference fit. Specifically, it is preferable that a portion where the cylinder walls are in an interference fit is ½ or more of a height h2(seeFIG. 5) of the outer cylinder wall13. According to this configuration, an effect of enhancing the rigidity by the interference fit can be exerted easily.

Furthermore, as described above, in the present embodiment, the mounting groove16(seeFIG. 3) is formed on the lower piece10, and the lower end portion21aof the inner cylinder wall21of the upper piece20is fitted into and engages with the mounting groove16. Thus, it is possible to prevent the lower end portion21afrom being suspended, and it is also possible to prevent the inner cylinder wall21from being suspended along the outer cylinder wall13. Also in this respect, the rigidity of the hub5can be enhanced.

It should be noted that as long as rigidity necessary for the hub5is ensured by a fit engagement between the outer cylinder wall13and the inner cylinder wall21, the mounting groove16may be omitted.

According to the present embodiment, the rigidity of the hub5can be enhanced without increasing the wall thickness of the outer cylinder wall13and the inner cylinder wall21. Therefore, the wall thicknesses of the flanges14and22, the outer cylinder wall13, and the inner cylinder wall21can be easily made uniform as much as possible, and the sink marks that appear due to the molding can be prevented effectively. Furthermore, it is not necessary to include a glass filler and the like in the outer cylinder wall13and the inner cylinder wall21. Thus, an increase in the product unit price can be suppressed, and a burden on a molding machine and a mold can be reduced.

FIG. 5is a cross-sectional view showing another example of the present embodiment. This figure corresponds to the cross-sectional view ofFIG. 3. In the configuration shown inFIG. 3, the inner cylinder wall21is entirely in contact with the outer cylinder wall13in the height direction. In contrast, in the configuration shown inFIG. 5, the area on the inner cylinder wall21that is in contact with the outer cylinder wall13is only about half the size of the height h2of the outer cylinder wall13.

According to this configuration, part of the outer cylinder wall13from the upper end portion13ato the center of the outer cylindrical wall13in the height direction where deformation due to being tightened by winding the recoding tape is likely to occur can be supported by the inner cylinder wall21from the back side. More specifically, it is preferable that a height h1of the inner cylinder wall21, which is from a base portion21bto the upper end portion21a, is ½ or more of the height h2of the outer cylinder wall13, which is from a base portion13bto the upper end portion13a.

FIG. 6is an exploded perspective view showing yet another example of the present embodiment. A tape reel51shown in this figure is for a tape cartridge having a reel locking mechanism. The reel locking mechanism regulates rotation of the tape reel51when the tape cartridge is not in use, and it releases the regulation and allows the tape reel51to rotate when the tape cartridge is in use.

Since the basic configuration of the tape reel51is similar to that of the tape reel1shown inFIG. 1, hereinafter the differences will be mainly described. An upper piece40is composed of an inner cylinder wall41and a disk-shaped upper flange42formed so as to project from the upper end of the inner cylinder wall41. Notches43are formed on the inner cylinder wall41. Although details will be described later, when the inner cylinder wall41is fitted into and engages with an outer cylinder wall33of a lower piece30, the portions on which the notch43is formed are not in a double cylinder form but in a single cylinder form.

The lower piece30is composed of a cylindrical body35and a disk-shaped lower flange34. The cylindrical body35is composed of a hub bottom wall31and an outer cylinder wall33. Gears36are formed on the lower surface of the hub bottom wall31along the circumference of the outer cylinder wall33.

A non-gear portion37on which the gear36is not formed is provided between the adjoining gears36. Holes38are formed inside the outer cylinder wall33so as to correspond to the non-gear portions37.

A lock releasing member52includes three hooks53, and the three hooks53respectively engage with the three holes38. A pressure member54is pressed against the hub bottom wall31side by the repulsion of a spring56. Furthermore, a cross-shaped groove55of the pressure member54engages with a cross-shaped rib57that is formed integrally with the case3(seeFIG. 4).

By this engagement, rotation of the pressure member54is regulated. Further, since the gears36on the hub bottom wall31engage with a gear formed on the back surface of the pressure member54that is regulated from being rotated, the rotation of the tape reel51is also regulated.

When rotating the tape reel51, by the hooks53being lifted by a drive shaft (not shown) of a tape drive, the pressure member54is lifted against the repulsion of the spring56and the engagement between the gears36on the hub bottom wall31and the gear on the back surface of the pressure member54is released.

In this state, the tape reel51becomes rotatable. Specifically, the tape reel51is rotated due to the rotation of the drive shaft in a state where a gear on the drive shaft of the tape drive and the gear on the lower surface of the tape reel51are in engagement.

FIG. 7is a perspective view showing a state in which the lower piece30and the upper piece40are coupled.FIG. 8is a cross-sectional view along the line B-B inFIG. 7. In the state shown inFIG. 7, the inner cylinder wall41of the upper piece40is fitted into the outer cylinder wall33(seeFIG. 6) of the lower piece30. As shown inFIGS. 7 and 8, from the portions on which the notch43is formed, the outer cylinder wall33of the lower piece30is exposed. That is, the portions are not in a double cylinder form but in a single cylinder form.

As shown inFIG. 8, the hook53of the lock releasing member52and the hole38are in engagement. An end surface52aof the lock releasing member52is in a step formed between the inner surface of the inner cylinder wall41and the outer surface of the outer cylinder wall33by the notch43.

Here, as shown inFIG. 3, when the inner cylinder wall21of the upper piece20is fitted into the outer cylinder wall13of the lower piece10, the inner diameter of the space above the hub bottom wall11becomes small by the wall thickness of the inner cylinder wall21. When attaching the lock releasing member52as inFIG. 6, this configuration is disadvantageous for ensuring the size of space to which the lock releasing member52is attached.

In the embodiment shown inFIGS. 7 and 8, the end surface52aof the lock releasing member52is in a step formed between the inner surface of the inner cylinder wall41and the outer surface of the outer cylinder wall33by the notch43. In other words, the space achieved by this step is used as space to which the lock releasing member52is attached. Therefore, in the configuration shown inFIGS. 6to8, even when the locking mechanism is housed in the cylindrical portion, the thickness of the inner cylinder wall41can be ensured while maintaining the outer dimensions of the outer cylinder wall33. Thus, a highly rigid double wall structure can be achieved.

In the above embodiment, the cylindrical hubs are composed respectively of the outer cylinder wall13of the lower pieces10and the inner cylinder wall21of the upper pieces20, and the outer cylinder wall33of the lower pieces30and the inner cylinder wall41of the upper pieces40. However, these inner and outer cylinder walls may be the other way around. That is, an inner cylinder wall may be provided on the lower pieces10and30, an outer cylinder wall may be provided on the upper pieces20and40, and the inner cylindrical walls and the outer cylinder walls may be respectively brought into a fit engagement.

The method for fixing the outer cylinder wall13and the inner cylinder wall21to each other and the outer cylinder wall33and the inner cylinder wall41to each other is not limited to interference fit, and various methods can be used. For example, each pair may be fixed to each other by setting the outer dimensions of the inner cylinder walls21and41slightly smaller than the inner dimensions of the outer cylinder walls13and33, and welding each pair after clearance fitting each inner cylinder wall and each outer cylinder wall.

As described above, according to the present invention, it is possible to prevent the hub from being tilted inwardly by enhancing the rigidity of the hub with a simple configuration. Therefore, the tape reel of the present invention is useful as, for example, a tape reel housed in a tape cartridge.