Recording tape cartridge

A recording tape cartridge has a case rotatably accommodating a single reel on which a recording tape is wound, an opening formed in portions of a front surface and a side surface adjacent to a corner portion of the case, and a door opening and closing the opening by rotating. The opening is for pulling-out of a leader member attached to an end portion of the recording tape. The door is structured so as to be able to cover the corner portion of the case including a portion of a top surface and/or a bottom surface when the door closes the opening.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a recording tape cartridge which accommodates, within a case, a single reel on which is wound a recording tape, such as a magnetic tape or the like, which is used mainly as a recording/playback medium for computers or the like.

2. Description of the Related Art

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 for computers or the like, is wound on a single reel, and the reel is accommodated within a case. Such a recording tape cartridge has a substantially rectangular box-shaped case. As shown inFIGS. 16A and 16Bfor example, a case102of a recording tape cartridge100is structured by an upper case104and a lower case106, each of which is substantially shaped as a tray, being joined together in a state in which peripheral walls104A,106A thereof abut one another. A single reel108, on which a recording tape T is wound, is rotatably accommodated within the case102.

A leader member110, such as a leader tape or the like, is fixed to an end portion of the recording tape T. The leader member110is pulled-out by a pull-out member (not illustrated) of a drive device. The pull-out member is usually provided at both side portions of a loading opening into which the recording tape cartridge100is loaded. Therefore, an opening112formed at the recording tape cartridge100is usually formed at a corner portion102C of the case102. Even if the opening112is not provided at the corner portion102C, there are cases in which regions which are important to the functioning of the recording tape cartridge100, such as a supporting shaft116of a door114which opens and closes the opening112, or the like, exist in a vicinity of the corner portion102C.

This corner portion102C is the place where it is easiest to receive a concentration of stress when an impact is received such as when the recording tape cartridge100is dropped or the like. When a concentration of stress is received at the corner portion102C, local, permanent deformation (crushing, bending, portions breaking off, or the like) occurs at that corner portion102C, and problems arise in that the recording tape cartridge100cannot be loaded into a drive device, the recording tape T cannot be pulled out, the door114which opens and closes the opening112cannot open and close, or the like.

Further, even if permanent deformation does not occur, the leader member110(such as a leader tape or the like) may come out from its held position within the case102, or get sandwiched between the peripheral wall104A of the upper case104and the peripheral wall106A of the lower case106, or fly out of the case102if the door114opens, due to the occurrence of temporary flexural deformation, i.e., elastic deformation such that the peripheral wall104A of the upper case104and the peripheral wall106A of the lower case106move apart from one another.

Moreover, in order to prevent temporary flexural deformation, it has been thought to weld together or screw together the peripheral wall104A of the upper case104and the peripheral wall106A of the lower case106in a vicinity of the corner portion102C. However, in such cases, conversely, the path by which the impact force (the energy) received at the time of a drop escapes is eliminated, and permanent deformation is promoted.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a recording tape cartridge in which it is difficult for trouble such as deformation or the like to occur even if impact is applied thereto due to a drop or the like, and which has excellent impact resistance.

In order to achieve the above-described object, the recording tape cartridge relating to the present invention and recited in claim1comprises: a case rotatably accommodating a single reel on which a recording tape is wound; and an opening formed in a vicinity of a corner portion of the case, the opening being for pulling-out of a leader member attached to an end portion of the recording tape, wherein a cover member, which covers the corner portion of the case including a portion of a top surface and/or a bottom surface of the case, is provided so as to be rotatable.

In accordance therewith, even if impact is applied due to a drop or the like to the vicinity of the corner portion of the case where the opening is formed, the corner portion, including a portion of the top surface and/or the bottom surface, is covered by the cover member. Therefore, permanent deformation such as breakage or the like does not occur. Further, even if a vicinity of the corner portion attempts to flexurally deform temporarily due to the impact, the cover member covers portions of the top surface and the bottom surface of the case. Therefore, the deformation is suppressed by the cover member. Accordingly, problems, such as the leader member dropping out from the position at which it is held, do not occur.

Further, the recording tape cartridge relating to the present invention and recited in claim4comprises: a case rotatably accommodating a single reel on which a recording tape is wound; an opening formed in a vicinity of a corner portion of the case, the opening being for pulling-out of a leader member attached to an end portion of the recording tape; and a door opening and closing the opening, wherein the door is structured so as to be able to cover the corner portion of the case including a portion of a top surface and/or a bottom surface of the case, when the door closes the opening.

In accordance therewith, even if impact is applied due to a drop or the like to the vicinity of the corner portion of the case where the opening is formed, the door which opens and closes the opening covers the corner portion of the case, including a portion of the top surface and/or the bottom surface. Therefore, permanent deformation such as breakage or the like does not occur in a vicinity of the corner portion. Further, even if a vicinity of the corner portion attempts to flexurally deform temporarily due to the impact, the deformation is suppressed by the door because the door covers portions of the top surface and the bottom surface of the case. Accordingly, problems, such as the leader member dropping out from the position at which it is held, do not occur.

Further, the recording tape cartridge relating to the present invention and recited in claim8comprises: a case rotatably accommodating a single reel on which a recording tape is wound; an opening formed in portions of a front surface and a side surface adjacent to a corner portion of the case, the opening being for pulling-out of a leader member attached to an end portion of the recording tape; and a door opening and closing the opening by rotating, wherein the door is structured so as to be able to cover the corner portion of the case including a portion of a top surface and/or a bottom surface of the case, when the door closes the opening.

In accordance therewith, even if impact is applied due to a drop or the like to the corner portion of the case, the door, which opens and closes the opening which is formed in portions of the front surface and the side surface adjacent to the corner portion, covers the corner portion of the case, including a portion of the top surface and/or the bottom surface. Therefore, permanent deformation such as breakage or the like does not occur in a vicinity of the corner portion. Further, even if the corner portion attempts to flexurally deform temporarily due to the impact, the deformation is suppressed by the door because the door covers portions of the top surface and the bottom surface of the case. Accordingly, problems, such as the leader member dropping out from the position at which it is held, do not occur.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described in detail on the basis of the drawings. Note that, for convenience of explanation, the direction of loading the recording tape cartridge into a drive device is denoted by arrow A, and this direction is the front direction. Further, arrow B denotes the leftward direction. Front/back, left/right, and top/bottom are expressed by using these directions as references.

As shown inFIG. 1, a recording tape cartridge10has a substantially rectangular box-shaped case12. The case12is structured by an upper case14and a lower case16, which are formed of synthetic resin, being joined together by ultrasonic welding or screws or the like in a state in which peripheral walls14B,16B thereof abut one another. A label area46is formed at a top surface14A of the upper case14.

As shown inFIG. 2, a single reel18is rotatably accommodated within the case12. A recording tape T, which is a magnetic tape or the like and which serves as an information recording/playback medium, is wound around the reel18. A reel gear19is formed in an annular form in the bottom surface of the reel18, and is exposed from a gear opening44formed in the lower case16(refer toFIGS. 10B,11B, and12B).

An opening20, which is for pulling out to the exterior the recording tape T wound on the reel18, is formed in a vicinity of a front left corner portion12C of the recording tape cartridge10. Namely, as shown inFIG. 3, the opening20is formed so as to extend over portions of a front surface12A and a left side surface12B which are adjacent to the corner portion12C. A leader tape22, which is fixed to an end portion of the recording tape T, is pulled-out from the opening20.

Here, the corner portion in the present invention means the ridge line portion where the peripheral walls14B,16B of the substantially rectangular box-shaped case12intersect one another at a substantially right angle or an obtuse angle in plan view. Accordingly, the corner portion12C in this case means the ridge line portion where the front surface12A and the left side surface12B intersect one another at a substantially right angle as seen in plan view.

Further, the vicinity of the corner portion12C where the opening20is formed means the corner portion12C, and portions of the front surface12A and/or the left side surface12B adjacent to or in the neighborhood of the corner portion12C, or a portion of at least one of the top surface14A and the bottom surface16A and portions of the front surface12A and/or the left side surface12B adjacent to or in the neighborhood of the corner portion12C. Note that the opening20may be provided in a vicinity of a front right corner portion12D.

The leader tape22is a member-to-be-pulled-out which a pull-out member (not illustrated) of a drive devices engages with in order to pull the recording tape T out. An engagement hole22A, with which the pull-out member engages, is formed in the distal end of the leader tape22. As shown inFIGS. 2 and 3, jutting-out portions22B, which jut out upwardly and downwardly, are formed in a vicinity of the distal end of the leader tape22. The leader tape22is held within the case12due to the jutting-out portions22B being anchored at engagement grooves24formed in the inner surfaces of the upper case14and the lower case16near the left side surface12B.

When the recording tape cartridge10is not in use, the opening20is closed by a door30. The door30is formed by a closing member32and a cover member34. The closing member32is formed in a substantial L shape as seen in plan view, so as to be the same configuration and size as the opening20(seeFIGS. 4A and 4B). The cover member34is connected integrally to the closing member32, and covers, from the outside, the corner portion12C, and portions of the front surface12A, the left side surface12B, the top surface14A, and the bottom surface16A of the case12which are adjacent to or in the neighborhood of the corner portion12C.

In this way, when the cover member34covers the corner portion12C including portions of the top surface14A and the bottom surface16A, even if the impact of a drop is received, permanent deformation such as breakage or the like at this place is prevented. Further, the cover member34covers a region including the corner portion12C while nipping portions of the top surface14A and the bottom surface16A of the case12. Therefore, even if impact of a drop is received, it is possible to suppress temporary flexural deformation at this place, i.e., flexural deformation in which the peripheral wall14B of the upper case14and the peripheral wall16B of the lower case16move apart from one another. Namely, the cover member34is not a structure for closing the opening20, but rather, is a structure for reinforcing the corner portion12C.

Note that the closing member32and the cover member34may respectively be molded of resin, or may be formed by a metal such as SUS or the like. In the case in which the closing member32and the cover member34are formed of metal, they may be formed by pressing (including deep drawing), die casting, or the like, and the thickness thereof is preferably 0.3 to 0.5 mm. Further, either one of the closing member32and the cover member34may be formed of resin and the other formed of metal. In the case in which one is formed of resin and the other of metal, they may be joined together by adhesion, caulking, fitting, insert molding, outsert molding, or any method of joining.

As shown inFIG. 3, a supporting shaft26, which is the fulcrum of rotation of the door30, projects at the upper case14and the lower case16. The portion of the supporting shaft26at the upper case14side is a tubular boss26A, whereas the portion at the lower case16side is a solid cylindrical boss26B. The supporting shaft26is structured by the distal end (upper end) of the boss26B at the lower case16side being fit into the boss26A at the upper case14side. Accordingly, the diameter of the boss26B is slightly smaller than the diameter of the boss26A.

Rotating/sliding portions36, which are fit with play at the supporting shaft26, are provided in a vicinity of the right end portion of the closing member32of the door30. The rotating/sliding portions36extend from the inner surface of the closing portion32at both of the top and bottom end portions and at the intermediate portion thereof. A through hole36A is formed in each of the rotating/sliding portions36(seeFIG. 6B). Accordingly, the door is rotatably supported due to the supporting shaft26being inserted through the through holes36A.

Further, an annular convex portion37is formed around the through holes36A at the top surface of the rotating/sliding portion36at the top end portion and at the bottom surface of the rotating/sliding portion36at the bottom end portion. Due to the annular convex portions37contacting the upper case14and the lower case16, gaps of about 0.3 mm to 0.5 mm each are formed between the top edge of the closing member32and the upper case14, and between the bottom edge of the closing member32and the lower case16.

In accordance with such a structure, the upper case14and the lower case16contact only the annular convex portions37, and the upper and lower edges of the closing member32are always in a state of not contacting the upper case14and the lower case16. Therefore, the sliding resistance of the door30(the closing member32) with respect to the upper case14and the lower case16is reduced. Note that, if the closing member32and the cover member34are formed of resin and metal, it is preferable that at least the rotating/sliding portions36and the annular convex portions37are formed of an olefin resin such as POM or the like. In accordance therewith, the sliding resistance of the door30(the closing member32) with respect to the upper case14and the lower case16can be reduced even more, and the sliding resistance with respect to the supporting shaft26also can be reduced.

Moreover, as shown inFIGS. 4A,4B and5B, the supporting shaft26is inserted through a wound portion28A of a torsion spring28, which always urges the door30in the direction of closing the opening20. Namely, the boss26B, which is the boss having the smaller diameter, is inserted through the wound portion28A of the torsion spring28in a state in which the wound portion28A is held between the rotating/sliding portion36at the bottom end portion and the rotating/sliding portion36at the intermediate portion. One end portion28B of the torsion spring28is anchored on a screw boss25of the case12(in this case, a screw boss projecting from the lower case16), whereas another end portion28C is anchored on the inner surface of the closing member32at the right rear end portion thereof.

In this way, when the screw boss25is provided independently of the supporting shaft26and is disposed in a vicinity of the supporting shaft26, the impact force at the time of a drop is received at the screw boss25. Therefore, it is difficult for the impact force to be transmitted to the supporting shaft26. Accordingly, deformation, breakage, and the like of the supporting shaft26is prevented. Moreover, when the wound portion28A of the torsion spring28is disposed between the rotating/sliding portions36, in a case in which the rotating/sliding portions36are formed of an olefin resin such as the aforementioned POM or the like, it is more difficult for the supporting shaft26to be scratched than in a case in which the case12is formed of a resin such as PC or the like. Namely, even if the wound portion28A of the torsion spring28slides due to rotation of the door30, it is difficult for powder due to abrasion or the like to be generated. Accordingly, the magnetic tape T is not adversely affected.

In any case, in accordance with the above structure, when the door30is opened, an opening/closing member (not illustrated) of the drive device enters in relatively from the front surface12A side and pushes the right end portion of the closing member32rearward. Then, as shown inFIGS. 4A and 4B, the door30rotates clockwise in plan view around the supporting shaft26against the urging force of the torsion spring28, and opens the opening20.

Further, as shown inFIGS. 2 through 5B, concave surface portions40which match the configuration of the cover member34are formed in a vicinity of the corner portion12C of the case12, i.e., in the top surface14A, the bottom surface16A, the front surface12A and the left side surface12B. A depth D of the concave surface portion40is formed such that the cover member34is L=0.05 mm or more lower than at least the top surface14A, the bottom surface16A and the left side surface12B when the door30closes the opening20. With such a structure, when the recording tape cartridge10is loaded into a drive device, problems such as the cover member34catching on the loading opening do not occur.

A pair of abutting portions38project at the top end and the bottom end of the inner surface of the cover member34which inner surface faces the front surface12A when the opening20is closed. When the opening20is closed, the abutting portions38abut engaging concave portions42which project at the inner surface of the case12adjacent to the engaging grooves24.

As shown inFIGS. 4A,5B,6A, and6B, the relationship between a clearance S1between the cover member34and the concave surface portion40, i.e., between, on the one hand, the cover member34, and, on the other hand, the top surface14A, the bottom surface14A and the left side surface12B of the case12, and a clearance S2between the supporting shaft26and the through hole36A, and a clearance S3between the abutting portion38and the engaging concave portion42, is S1, S2>S3.

Accordingly, if an impact is applied to the cover member34which covers the vicinity of the corner portion12C due to a drop or the like, first, the impact force is received to a certain extent due to the abutting portions38strongly abutting the engaging concave portions42. Therefore, the impact force applied between the cover member34and the concave surface portions40, and between the supporting shaft26and the through holes36A, can be lessened, and breakage, deformation, and the like of these portions can be prevented.

Further, the cover member34shown inFIGS. 1 through 5Bwidely covers portions of the front surface12A, the left side surface12B, the top surface14A and the bottom surface16A of the case12, including the corner portion12C. However, the cover member34is not limited to the illustrated structure. For example, as shown inFIG. 7A, the cover member34may be formed to a size such that it can cover at least the corner portion12C and edges (ridge line portions)12E which are the boundary portions of the top surface14A and the bottom surface16A with the front surface12A and the left side surface12B.

Further, as shown inFIG. 7B, the cover member34may be formed to a size such that it can cover only the corner portion12C and the portion of the top surface14A contiguous to the corner portion12C. Or, as shown inFIG. 7C, the cover member34may be formed to a size such that it can cover only the corner portion12C and the portion of the bottom surface16A contiguous to the corner portion12C. However, when the cover member34is structured so as to cover portions of both the top surface14A and the bottom surface16A so as to nip the case12from the top and bottom, not only can permanent deformation be prevented, but also, temporary flexural deformation can be suppressed. Therefore, such a structure is preferable.

Next, operation of the door30in the recording tape cartridge10having the above-described structure will be described. When the recording tape cartridge10is not in use, the door30closes the opening20. Namely, the closing member32closes the opening32, and the cover member34is fit together with the concave surface portions40and covers them.

In this way, when the cover member34presses, from above and below, the corner portion12C at which the opening20is formed (i.e., when the cover member34nips the case12from the top surface14A and the bottom surface16A), even if impact is applied to a vicinity of the corner portion12C due to a drop or the like, permanent deformation such as breakage or the like can be prevented. Further, temporary flexural deformation, such as the peripheral wall14B of the upper case14and the peripheral wall16B of the lower case16separating from one another, can be suppressed. Accordingly, problems such as the leader tape22dropping out from the engaging grooves24(the holding position) do not occur.

The clearance S3between the abutting portion38and the engaging concave portion42is smaller than the clearance S1between the cover member34and the concave surface portion40, and the clearance S2between the supporting shaft26and the through hole36A. Therefore, the impact force applied due to a drop or the like is first received at the abutting portions38and the engaging concave portions42. Accordingly, because it is possible for the impact force to not be directly transmitted to the supporting shaft26for example, it is possible to prevent breakage, deformation or the like of the supporting shaft26. Moreover, because the screw boss25is disposed in a vicinity of the supporting shaft26, the impact force at the time of a drop is received by the screw boss25as well. Accordingly, breakage or deformation of the supporting shaft26can be prevented even more.

Moreover, when the cover member34is covering the concave surface portions40(i.e., when the opening20is closed), the cover member34is 0.05 mm or more lower (i.e., concave) than the top surface14A, the bottom surface16A, and the left side surface12B. Accordingly, when the recording tape cartridge10is loaded into a drive device, problems such as the cover member34catching on the loading opening do not occur.

Further, when the recording tape cartridge10is loaded into a drive device and the door30rotates (i.e., at times of opening and closing the opening20), a slight gap is formed by the annular convex portions37between the closing member32and the case12(the upper case14and the lower case16). Therefore, there is little sliding resistance of the door30(the closing member32) with respect to the case12. In addition, at the door30(the closing member32), if at least the rotating/sliding portions36and the annular convex portions37are formed of an olefin resin such as POM or the like, the sliding resistance can be made to be even smaller, as compared with that of a case12(including the supporting shaft26) which is formed of a resin such as PC or the like.

In any case, the door30has, separately from the closing member32which closes the opening20, the cover member34which can cover the corner portion12C including portions of the top surface14A and the bottom surface16A. Therefore, even if impact is applied to a vicinity of the corner portion12C due to a drop or the like, permanent deformation and temporary flexural deformation do not occur. Namely, by providing the cover member34, the recording tape cartridge10having excellent impact resistance can be provided. Note that it is possible to provide the cover member34not only at the corner portion12C at which the opening20is provided, but also at other corner portions, such as, for example, the corner portion12D or the like where the opening20is not provided.

Next, explanation will be given of another embodiment which prevents permanent deformation and flexural deformation without providing the cover member34. Note that portions which are the same as those described above are denoted by the same reference numerals, and description thereof is omitted. As shown inFIG. 8, a thin-plate-shaped reinforcing member50is provided integrally at the upper case14and/or the lower case16in a vicinity of the opening20.

Namely, a concave surface portion48of a predetermined depth which extends over portions of the front surface12A and the left side surface12B, is formed in a portion of the top surface14A of the upper case14and/or the bottom surface16A of the lower case16contiguous to the corner portion12C. The reinforcing member50which is made of metal is joined to the concave surface portion48. With such a structure, if impact is applied to a vicinity of the corner portion12C due to a drop or the like, permanent deformation such as breakage or the like can be prevented.

The method of joining at this time may be any method of joining such as caulking, adhesion, fitting, insert molding, or the like. The metal reinforcing member50may be formed by pressing (including deep drawing) or die casting. The metal material is preferably a metal which is hard and difficult to rust, such as SUS or the like. Moreover, the reinforcing member50may be formed of metal and resin.

When the reinforcing members50are provided at the top surface14A and the bottom surface16A, as shown inFIG. 9, the top and bottom reinforcing members50may be connected integrally by connecting portions50A at regions which do not obstruct the opening20and rotation of the door30(the closing member32). When such a configuration is used, if impact is applied to the corner portion12C due to a drop or the like, permanent deformation such as breakage or the like can be prevented, and flexural deformation, such as the peripheral walls14B,16B temporarily moving apart from one another, also can be suppressed.

It is possible to provide the connecting portion50A at only the front surface12A or at only the left side surface12B. However, providing the reinforcing portion50A at both the front surface12A and the left side surface12B is preferable as flexural deformation can be suppressed even more. In the same way as the above-described cover member34, is preferable that the place where the reinforcing member50is provided is L=0.05 mm or more lower (i.e., concave) than the top surface14A, the bottom surface16A, and the left side surface12B.

The reinforcing member50is not limited to being provided in a vicinity of the opening20(a vicinity of the corner portion12C). It is preferable that the reinforcing member50is provided at portions of the top surface14A and/or the bottom surface16A contiguous to each corner portion, including the corner portion12C. Further, it is possible to provide the reinforcing member50not only at the outer surface side of the case12, but also at the inner surface side of the case12.

In addition, it is preferable to utilize a structure in which the recording tape cartridges10cannot be stacked with their front and rear sides reversed (cannot be stacked reversely). An example of a structure preventing reverse stacking is as follows: as shown inFIGS. 10A and 10B, a pair of long, thin stacking ribs52, whose interval at the front side is narrow and whose interval at the rear side is wide, may be formed in the bottom surface16A, and a stacking concave portion54, with which the stacking ribs52fit together, may be formed in the top surface14A. In this case, the stacking concave portion54may also serve as the label area46. Or, the stacking concave portion54and the label area46may be provided separately.

The following structure also can be considered as stacking ribs for not allowing reverse stacking. As shown inFIGS. 11A and 11Bfor example, a plurality (e.g., four) stacking ribs56of predetermined sizes may be formed in the bottom surface16A, and the positions of the stacking ribs56at the front side and at the rear side can be made to be different positions. Namely, an interval W1between the stacking ribs56at the front side is made to be narrow, whereas an interval W2between the stacking ribs56at the rear side is made to be wide. The same number of stacking concave portions58, which match the stacking ribs56, are formed in the top surface14A. Reverse stacking is prevented by such a structure as well. Note that, in this case, because the stacking concave portions58cannot also function as the label area46, as illustrated, the label area46may be provided appropriately between the stacking concave portions58or the like. The numbers of the stacking ribs56and the stacking concave portions58may be three or less, but in consideration of stability, four or more is preferable.

Further, as shown inFIGS. 12A and 12Bfor example, a plurality (e.g., four) stacking ribs60which are trapezoidal in plan view may be formed in the bottom surface16A. In this case, there is no need to make the positions at the front side and at the rear side offset from one another. Namely, an interval W3between the stacking ribs60at the front side and an interval W4between the stacking ribs60at the rear side may be made to be the same. The same number of stacking concave portions62, which match the stacking ribs60, are formed in the top surface14A. Reverse stacking is prevented by such a structure as well. Note that, in this case as well, because the stacking concave portions62cannot also function as the label area46, as illustrated, the label area46may be provided appropriately between the stacking concave portions62or the like. The numbers of the stacking ribs60and the stacking concave portions62may be three or less, but in consideration of stability, four or more is preferable.

Moreover, as shown inFIGS. 13A and 13Bfor example, a pair of stacking ribs64may be provided so as to be set apart from one another by a predetermined interval in the front edge of the bottom surface16A, and a substantially V-shaped or substantially U-shaped stacking rib65may be provided at the rear side of the bottom surface16A. The end portions of this stacking rib65which is provided at the rear side are positioned in vicinities of the rear side corner portions, and the central, bent portion of the stacking rib65is positioned in a vicinity of the gear opening44. Stacking concave portions66,67matching the stacking ribs64,65are formed in the top surface14A. Reverse stacking is prevented by such a structure as well. Note that, in this case as well, because the stacking concave portions66,67cannot also function as the label area46, as illustrated, the label area46may be provided appropriately between the stacking concave portions66and the stacking concave portion67or the like.

In addition, as shown inFIGS. 14A and 14Bfor example, long and thin stacking ribs68of different lengths may be provided in the front edge and the rear edge of the bottom surface16A. A length W6of the rear side stacking rib68is formed to be longer than a length W5of the front side stacking rib68, although an opposite structure may be used (i.e., the front side stacking rib68may be longer than the rear side stacking rib68). Stacking concave portions70matching the stacking ribs68are formed in the top surface14A. Reverse stacking is prevented by such a structure as well. Note that, in this case as well, because the stacking concave portions70cannot also function as the label area46, as illustrated, the label area46may be provided appropriately between the stacking concave portions70or the like.

Still further, as shown inFIGS. 15A and 15Bfor example, long and thin stacking ribs72of different lengths may be provided in the left side edge and the right side edge of the bottom surface16A. A length W8of the stacking rib72at the right side edge is formed to be shorter than a length W7of the left side edge stacking rib72, although an opposite structure may be used (i.e., the stacking rib72at the left may be shorter than the stacking rib72at the right). Stacking concave portions74matching the stacking ribs72are formed in the top surface14A. Reverse stacking is prevented by such a structure as well. Note that, in this case as well, because the stacking concave portions74cannot also function as the label area46, as illustrated, the label area46may be provided appropriately between the stacking concave portions74or the like.

In any case, the stacking ribs52,56,60,64,65,68,72and the stacking concave portions54,58,62,66,67,70,74may be formed in any configuration provided that they are configurations which together do not allow reverse stacking.