Recording tape cartridge

When a recording tape cartridge is not in use, rotation of a reel, which abuts an annular rib of a floor plate of a case, is locked by a braking member which meshes together from above with an engaging gear, and a gap between the braking member and a spacer wall of a ceiling plate is filled-in by a spacer portion of a spacer member, and movement away from the annular rib is impeded. When, due to operation of a drive device, the spacer portion enters into a relief portion of the braking member which relief portion opens upwardly, the braking member is raised up by an amount corresponding to the gap formed between the braking member and the spacer wall, and meshing of the braking member and the engaging gear is cancelled. The reel thereby becomes able to rotate and to move away from the annular rib.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 from Japanese Patent Application No. 2003-316729 the disclosures of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a recording tape cartridge which rotatably accommodates a reel around which a recording tape, such as a magnetic tape or the like, is wound.

2. Description of the Related Art

Recording tapes such as magnetic tapes and the like are used as external recording media for computers and the like. Little space is required to accommodate such a recording tape at the time of storage thereof, and a large amount of information can be recorded thereon. A so-called single-reel recording tape cartridge is used in which a single reel, on which such recording tape is wound, is rotatably accommodated within a case.

Such a recording tape cartridge has a braking means so that the reel does not rotate within the case when the recording tape cartridge is not in use (see, for example, Japanese Patent Application Laid-Open (JP-A) No. 63-251983 (Patent Document 1)). This Patent Document 1 discloses the following structure: an engaging gear is provided in an annular form at the floor surface of a reel hub which is shaped as a hollow cylinder having a floor and which structures the axially central portion of a reel. A locking member, which is disc-shaped and at which is provided a braking gear which can mesh with the engaging gear, is inserted within the reel hub. The locking member is supported so as to be unable to rotate with respect to the case, and so as to be slidable in the axial direction of the reel. Due to the urging force of a compression coil spring provided between the case and the locking member, the braking gear is made to mesh with the engaging gear of the reel. In this state, the reel is pressed against the floor plate of the case by the urging force of the compression coil spring. Rotation of the reel with respect to the case is locked due to the braking gear of the locking member meshing with the engaging gear due to this urging force.

In this structure, a pass-through hole is formed in the floor portion of the reel hub. When a releasing portion of a drive device enters in from this pass-through hole and pushes the locking member upward against the urging force of the compression coil spring, the meshed-together state of the braking gear and the engaging gear is cancelled, and rotation of the reel with respect to the case is permitted. The releasing portion of the drive device is provided at a rotating shaft together with a driving gear which meshes with a reel gear formed at an end surface of the reel hub. As the driving gear meshes with the reel gear, the releasing portion pushes the locking member upward. Accordingly, in this structure, when the rotating shaft drives and rotates the reel, the locking member, which cannot rotate with respect to the case, and the releasing portion, which rotates integrally with the rotating shaft, slidingly-contact one another while being pressed against one another due to the urging force of the compression coil spring. In order to reduce the resistance to rotation which arises accompanying this sliding-contact, the locking member and the releasing portion are both formed of resin materials.

Further, a structure which is similar to that disclosed in above-described Patent Document 1 has been conceived of in which a releasing member, which rotates integrally with the reel, is provided between the locking member and the floor portion of the reel hub (see, for example, Japanese Patent No. 3187022 (Patent Document 2)). Specifically, due to the releasing member being pushed by a releasing portion of a drive device, the releasing member is pushed upward together with the locking member against the urging force of the compression coil spring. In this way, the locking member is pushed upward by the releasing portion via the releasing member, and the locked state of the reel is cancelled. In this structure, due to the releasing member rotating integrally with the reel at the time when the reel is driven to rotate, the releasing portion and the releasing member do not slidingly-contact one another, and the releasing member and the locking member slidingly-contact one another.

Moreover, a structure is known in which, at the time when the reel is driven to rotate, the locking member does not slidingly-contact any other portion (see, for example, JP-A No. 11-25648 (Patent Document 3)). In this structure, the engaging gear is formed at the outer peripheral portion of a flange of the reel. Rotation of the reel is locked due to two locking members, each of which is rotatably supported within the case and is urged in a direction of meshing with the engaging gear, meshing together with the engaging gear. Further, when this recording tape cartridge is loaded into a drive device, the locking members are pushed by releasing portions of the drive device, and rotate against the aforementioned urging force. In this way, the meshing together of the locking members and the engaging gear is released, and rotation of the reel is permitted. These releasing portions are respectively provided independently of the rotating shaft, and push the locking members due to the loading of the recording tape cartridge (the case) into the drive device or the lowering of the recording tape cartridge (the case). In this structure, the compression coil spring, which is for pressing the reel against the case or the rotating shaft, is connected to the reel via a bearing. Relative rotation between the compression coil spring and the reel is absorbed by the bearing.

However, in the recording tape cartridges relating to the above-described structures, when the recording tape is not being used, the reel is held with respect to the case by being pressed against the floor plate of the case by the urging force of the compression coil spring. Therefore, when force resisting the urging force of the compression coil spring is applied, upward and downward movement of the reel within the case cannot be impeded. Thus, for example, if the region where the reel gear is formed at the reel, which region is exposed from the case (i.e., the outer surface of the floor portion of the reel hub), were to be pushed or if impact of a drop were to be applied to this region, the reel would joggle greatly within the case, which could be a cause of damage to the recording tape whose one end portion is held at the case via a leader member. Further, if the reel joggles within the case, the locking of the rotation of the reel by the locking member is released, which is a cause of the winding (the wound state) of the recording tape becoming tighter or looser.

SUMMARY OF THE INVENTION

In view of the aforementioned, an object of the present invention is to provide a recording tape cartridge in which a reel can be prevented from moving greatly in an axial direction within a case at times when the recording tape cartridge is not being used.

A recording tape cartridge of a first aspect of the present invention has: a case at which a ceiling plate and a floor plate are connected by a peripheral wall; a reel around which a recording tape is wound, the reel accommodated within the case so as to be able to approach and move away from the floor plate; an engaging portion provided at the reel, and facing the ceiling plate; a rotation locking member provided so as to be unable to rotate with respect to the case and so as to be able to approach and move away from the ceiling plate, and when the recording tape cartridge is not in use, the rotation locking member engages with the engaging portion of the reel which is abutting the floor plate and impedes rotation of the reel, and the rotation locking member is operated by a drive device and moves away from the engaging portion and allows the reel to rotate and to move away from the floor plate; and a spacer member provided between the ceiling plate and the rotation locking member, and when the recording tape cartridge is not in use, the spacer member fills-in a gap between the ceiling plate and the rotation locking member, and before the rotation locking member is operated by the drive device, the spacer member is operated by the drive device and is pulled-out from the gap.

In the recording tape cartridge of the first aspect, when the recording tape cartridge is not being used, the rotation locking member, which cannot rotate with respect to the case, engages with the engaging portion, which faces toward the ceiling plate, of the reel which is abutting the floor plate (including the fixed portion provided at the floor plate) within the case. Rotation of the reel with respect to the case is thereby impeded. Further, in this state, the spacer member (together with other portions of the case) fills-in the gap between the rotation locking member and the ceiling plate, and the reel moving away from the floor plate is impeded.

When, from this state, the drive device operates the spacer member and the spacer member is pulled-out from the aforementioned gap (the gap is formed between the rotation locking member and the ceiling plate due to the movement of the spacer member), movement of the rotation locking member toward the ceiling plate, i.e., the rotation locking member moving away from the engaging portion of the reel, is possible. Then, when the drive device operates the rotation locking member and the rotation locking member moves to the releasing position, the rotation locking member moves away from the engaging portion, the reel becomes able to rotate with respect to the case and to move away from the floor plate, and the reel moves away from the floor plate and is driven to rotate without contacting the case.

Here, because the spacer member, which fills in the gap between the ceiling plate and the rotation locking member when the recording tape cartridge is not being used, is provided, the reel does not move greatly in the axial direction within the case when the recording tape cartridge is not in use. Accordingly, for example, even if force in the axial direction were to be applied to the reel due to the impact of a drop or an erroneous operation or the like, the recording tape wound on the reel is protected. Further, because movement of the rotation locking member, together with that of the reel, within the case is restricted, it is also possible to prevent the locking of the rotation of the reel from being released due to the aforementioned impact of a drop or the like.

In this way, in the recording tape cartridge of the first aspect, it is possible to prevent the reel from moving greatly in the axial direction within the case when the recording tape cartridge is not in use. Note that it suffices for the engaging portion, which faces the ceiling plate, to be provided such that the locking member engages the engaging portion at the ceiling plate side. For example, the engaging portion may be provided at an incline with respect to the ceiling plate.

A recording tape cartridge relating to a second aspect of the present invention has: a reel having a hub which is formed in a shape of a cylindrical tube having a floor portion and around whose outer peripheral portion a recording tape is wound, and an engaging portion provided at an inner surface of the floor portion of the hub; a case at which a ceiling plate and a floor plate are connected by a peripheral wall, the case accommodating the reel, whose engaging portion is facing the ceiling plate, such that the reel can approach and move away from the floor plate; a rotation locking member provided so as to be unable to rotate with respect to the case and so as to be able to approach and move away from the ceiling plate, and when the recording tape cartridge is not in use, the rotation locking member engages with the engaging portion of the reel which is abutting the floor plate and impedes rotation of the reel, and the rotation locking member is operated by a drive device and moves away from the engaging portion and allows the reel to rotate and to move away from the floor plate; a relief portion provided at the rotation locking member and opening toward the ceiling plate; and a spacer member provided between the ceiling plate and the rotation locking member, and when the recording tape cartridge is not in use, the spacer member fills-in a gap between the ceiling plate and an end surface of the rotation locking member, and before the rotation locking member is operated by the drive device, the spacer member is operated by the drive device and enters into the relief portion.

In the recording tape cartridge of the second aspect, when the recording tape cartridge is not being used, the rotation locking member, which cannot rotate with respect to the case, engages with the engaging portion which is provided at the inner surface of the floor portion, which faces toward the ceiling plate, of the hub of the reel which is abutting the floor plate (including the fixed portion provided at the floor plate) within the case. Rotation of the reel with respect to the case is thereby impeded. Further, in this state, the spacer member (together with other portions of the case) fills-in the gap between the rotation locking member and the ceiling plate, and the reel moving away from the floor plate is impeded or markedly restricted.

When, from this state, the drive device operates the spacer member and the spacer member enters into the relief portion of the rotation locking member, a gap, which permits movement of the rotation locking member toward the ceiling plate, is formed between the rotation locking member and the ceiling plate, and movement of the rotation locking member toward the ceiling plate, i.e., the rotation locking member moving away from the engaging portion of the reel, is possible. Then, when the drive device operates the rotation locking member and the rotation locking member moves to the releasing position at which the rotation locking member is away from the engaging portion, the reel is able to rotate with respect to the case and to move away from the floor plate, and the reel moves away from the floor plate and is driven to rotate without contacting the case.

Here, because the spacer member, which fills in the gap between the ceiling plate and the rotation locking member when the recording tape cartridge is not being used, is provided, the reel does not move greatly in the axial direction within the case when the recording tape cartridge is not in use. Accordingly, for example, even if force in the axial direction were to be applied to the reel due to the impact of a drop or an erroneous operation or the like, the recording tape wound on the reel is protected. Further, because movement of the rotation locking member, together with that of the reel, in the axial direction of the reel and within the case is restricted, it is also possible to prevent the locking of the rotation of the reel from being released due to the aforementioned impact of a drop or the like.

The relief portion, into which the spacer member enters, is provided at the rotation locking member. Therefore, by a small moving stroke, the spacer member forms the aforementioned gap (is pulled out from the gap) and can permit movement of the rotation locking member toward the ceiling plate. Thus, the function of canceling the state in which axial direction movement of the reel is impeded can be realized by a relatively compact structure.

In this way, in the recording tape cartridge of the second aspect, it is possible to prevent the reel from moving greatly in the axial direction within the case when the recording tape cartridge is not in use. Note that the relief portion may be structured, for example, as a concave portion, a cut-out portion, a hole (a pass-through hole), or the like.

A recording tape cartridge of a third aspect of the present invention has the feature that, in the recording tape cartridge of the second aspect, the spacer member is structured to have an operation portion which is provided coaxially within the hub and is operated by the drive device and rotates around an axis of the hub, and a spacer portion which enters into the relief portion due to rotation of the operation portion.

In the recording tape cartridge of the third aspect, when the operation portion of the spacer member, which operation portion is disposed coaxially with the hub, is rotated by a drive device, the spacer portion slides along the surface of the rotation locking member which surface faces the ceiling plate, while the spacer portion rotates around the axial center of the reel. When this spacer portion reaches the region of the rotation locking member where the relief portion is formed, the spacer portion enters into the relief portion. In this way, the function of canceling the state in which axial direction movement of the reel is impeded can be realized by a simple structure.

A recording tape cartridge of a fourth aspect of the present invention has the feature that, in the recording tape cartridge of the third aspect, a plurality of the spacer portions and the relief portions are provided.

A recording tape cartridge of a fifth aspect of the present invention has the feature that, in the recording tape cartridge of the third aspect, an engaging portion that engages with the drive device is provided at an end portion of the operation portion of the spacer member.

A recording tape cartridge of a sixth aspect of the present invention has the feature that, in the recording tape cartridge of the second aspect, the spacer member is provided between a wall portion, which is provided at the ceiling plate in protruding manner toward the rotation locking member, and the rotation locking member, and when the recording tape cartridge is not in use, the spacer member fills-in the gap between an end portion of the wall portion and the end surface of the rotation locking member.

A recording tape cartridge of a seventh aspect of the present invention has the feature that, in the recording tape cartridge of the second aspect, a stopper wall is provided at an one end, in rotating direction of the rotation locking member, of an opening of the relief portion.

A recording tape cartridge relating to an eighth aspect of the present invention has: a case at which a ceiling plate and a floor plate are connected by a peripheral wall; a reel around which a recording tape is wound, the reel accommodated within the case so as to be able to approach and move away from the floor plate; an engaging portion provided at the reel, and facing the ceiling plate; a rotation locking member provided so as to be unable to rotate with respect to the case and so as to be able to approach and move away from the ceiling plate, and when the recording tape cartridge is not in use, the rotation locking member engages with the engaging portion of the reel which is abutting the floor plate and impedes rotation of the reel, and the rotation locking member is operated by a drive device and moves away from the engaging portion and allows the reel to rotate and to move away from the floor plate; and a spacer member provided between the ceiling plate and the rotation locking member, and when the recording tape cartridge is not in use, the spacer member fills-in a gap between the ceiling plate and the rotation locking member to restrict movement of the rotation locking member in axial direction such that movement of the reel away from the floor plate is impeded, and before the rotation locking member is operated by the drive device, the spacer member is operated by the drive device and is pulled-out from the gap to allow movement of the rotation locking member within the gap in the axial direction such that movement of the reel away from the floor plate is allowed.

A recording tape cartridge of a ninth aspect of the present invention has the feature that, in the recording tape cartridge of the eighth aspect, the recording tape cartridge further comprises a relief portion, provided at one of the rotation locking member side or the ceiling plate side, that can accommodate at least a portion of the spacer member.

A recording tape cartridge of a tenth aspect of the present invention has the feature that, in the recording tape cartridge of the eighth aspect, the spacer member is structured to have an operation portion which is provided coaxially within a hub of the reel and is operated by the drive device and rotates around an axis of the hub, and a spacer portion which enters into the relief portion due to rotation of the operation portion.

As described above, the recording tape cartridge relating to the present invention has the excellent effect that the reel can be prevented from moving greatly in the axial direction within the case at times when the recording tape cartridge is not in use.

DETAILED DESCRIPTION OF THE INVENTION

A recording tape cartridge10relating to an embodiment of the present invention will be described on the basis ofFIGS. 1A and 1BthroughFIGS. 8A and 8B.

(Overall Structure of Recording Tape Cartridge)

A perspective view, as seen from above and at an incline, of the recording tape cartridge10is shown inFIG. 1A. A perspective view, as seen from below and at an incline, of the recording tape cartridge10is shown inFIG. 1B. Sectional views of the recording tape cartridge10are shown inFIGS. 2A and 2B. Note that arrow A used appropriately in the respective drawings indicates the direction of loading the recording tape cartridge10into a drive device, and for convenience of explanation, the side in the direction of arrow A is the front side. Further, the direction indicated by arrow B is upward.

As shown in these drawings, the recording tape cartridge10has a case12. The case12is structured by an upper case14and a lower case16being joined together. Specifically, the upper case14is structured such that a substantially frame-shaped peripheral wall14B stands erect along the outer edge of a ceiling plate14A which is substantially rectangular in plan view. The lower case16is structured such that a peripheral wall16B stands erect along the outer edge of a floor plate16A which has a configuration substantially corresponding to that of the ceiling plate14A. The case12is formed in a substantial box shape by the upper case14and the lower case16being joined together by ultrasonic welding or screws or the like in a state in which the open end of the peripheral wall14B and the open end of the peripheral wall16B abut one another.

At a corner portion of the case12at the leading side in the direction of loading the recording tape cartridge10into a drive device, the ceiling plate14A, the peripheral wall14B, the floor plate16A and the peripheral wall16B are respectively cut away, such that an opening18, which is inclined with respect to the loading direction, is formed. A gear opening20, which is circular and passes through the floor plate16A, is formed in the substantially central portion of the floor plate16A. The gear opening20is for exposing a reel gear42which will be described later. An annular rib22formed in a tapered shape projects toward the inner side of the case12at the floor plate16A at the edge of the gear opening20, and is for positioning of a reel28which will be described later.

A pair of positioning holes24,26are formed in a vicinity of the front end of the outer surface of the floor plate16A of the case12. The pair of positioning holes24,26are formed in the shapes of bags within projections (not illustrated) which stand erect from the floor plate16A toward the interior of the case12. The positioning holes24,26are disposed so as to be separated from one another on an imaginary line which is orthogonal to the loading direction. The positioning hole24, which is the positioning hole which is closer to the opening18, is formed in a substantially square shape, as seen in bottom view, which circumscribes a positioning pin of a drive device. The positioning hole26is a long hole whose longitudinal direction runs along the aforementioned imaginary line, and whose width corresponds to the diameter of a positioning pin.

In this way, when the recording tape cartridge10is loaded into a drive device and positioning pins are inserted into the respective positioning holes24,26, the recording tape cartridge10is correctly positioned in the horizontal directions (the left/right direction and the front/back direction) within the drive device.

The portions of the floor plate16A around the positioning holes24,26are positioning surfaces24A,26A which are finished so as to be smoother than the other portions of the floor plate16A (the design surface of the floor plate16A). When the positioning pins are inserted into the positioning holes24,26, the positioning surfaces24A,26A abut positioning surfaces of the drive device which are provided around the positioning pins. In this way, the vertical direction positioning of the recording tape cartridge10within the drive device is carried out.

As shown inFIG. 2A, the reel28, which will be described in detail later, is rotatably accommodated within the above-described case12. Only one reel28is provided. A magnetic tape T serving as a recording tape is wound on the reel28. A leader block30, which serves as a pull-out member, is attached to the distal end of the magnetic tape T.

When the recording tape cartridge10is not being used, the leader block30is accommodated and held at the inner side of the opening18of the case12. In this state, the leader block30closes the opening18, and impedes entry of dust and the like into the case12. An engaging recess30A is formed in the distal end of the leader block30. When the magnetic tape T is to be pulled-out within the drive device, a pull-out means, which engages with the engaging recess30A, pulls the leader block30out of the case12and guides the leader block30to a take-up reel of the drive device. Moreover, the end surface of the leader block30at the side opposite the engaging recess30A is an arc-shaped surface30B. The arc-shaped surface30B is fit into the take-up reel and forms a portion of the take-up surface around which the magnetic tape T is taken-up.

Next, the reel28will be described. As shown inFIGS. 2A and 2B, the reel28has a reel hub32which serves as a hub and which structures the axially central portion of the reel28. The reel hub32is formed substantially in the shape of a hollow cylinder having a floor, and has a cylindrical portion34around whose outer peripheral surface the magnetic tape T is wound, and a floor portion36which closes the bottom portion of the cylindrical portion34. A lower flange38extends coaxially and integrally at the radial direction outer side of the reel hub32from a vicinity of the floor portion36side end portion (i.e., the lower end portion) of the reel hub32.

On the other hand, an upper flange40, which is formed in correspondence with the lower flange38, is joined to the upper end portion of the reel hub32. In this way, at the reel28, the magnetic tape T is wound around the outer peripheral surface of the cylindrical portion34of the reel hub32, between the opposing surfaces of the lower flange38and the upper flange40, and the cylindrical portion34is open toward the top.

The reel gear42is formed on the whole in the shape of a ring which is coaxial with the reel28, at the bottom end surface of the floor portion36of the reel hub32(i.e., the outer surface which is positioned further downward than the lower flange38). The reel gear42can mesh with a driving gear (not illustrated) which is provided in an annular form at the outer peripheral portion of the distal end of a rotating shaft of a drive device.

On the other hand, an engaging gear44, which serves as an engaging portion, is provided in a vicinity of the outer periphery of the top surface (the inner surface) of the floor portion36of the reel hub32. The engaging gear44is formed in the shape of a ring which is coaxial with the reel28, and respective teeth of the engaging gear44are directed upward (toward the ceiling plate14A). The engaging gear44can mesh with a braking gear56of a braking member52which will be described later. Note that the engaging gear44may be provided by being divided into plural portions which are disposed on a circumference which is coaxial with the reel28. Further, the engaging gear44may be formed along a conical surface which is inclined with respect to the axis of the reel28.

A pass-through hole46is provided in the axially central portion of the floor portion36of the reel hub32so as to pass through along the direction of plate thickness of the floor portion36. The pass-through hole46is for exposing a release operation portion62of the braking member52and an operation shaft portion80of a spacer member70which will be described later.

The portions of the above-described reel28, other than the upper flange40, are formed integrally by resin molding. A reel plate48, which is formed of a magnetic material and in the shape of a disc, is provided integrally and coaxially by insert molding at the inner side of the reel gear42at the bottom surface of the floor portion36of the reel hub32. The reel plate48is for attraction and holding (chucking) by a magnet (not illustrated) which is provided at the radial direction inner side of the driving gear at the rotating shaft. A through hole48A is formed in the axially central portion of the reel plate48in correspondence with the pass-through hole46.

The reel28is accommodated in the case12, and when the recording tape cartridge10is not in use, the reel28is set on the annular rib22. Specifically, as shown inFIG. 2AandFIG. 4, the portion of the reel28, which portion is the border between the floor portion36and the lower flange38, abuts the top end surface of the annular rib22. Due to the portion of the reel28which projects further than the lower flange38being set in at the inner side of the annular rib22, radial direction movement of the reel28is restricted. In the present embodiment, the top end surface of the annular rib22, which is formed integrally with (provided fixedly at) the floor plate16A, corresponds to the “floor plate” of the case12.

In this state, the reel28is exposed from the gear opening20, without the reel gear42and the reel plate48projecting out from the outer surface (the bottom surface) of the floor plate16A (seeFIG. 1B). Namely, the reel gear42and the reel plate48face the exterior of the case12from the gear opening20. In this way, operation, i.e., chucking (holding) and driving/rotating, of the reel28from the exterior of the case12is possible.

The height of the reel28from the bottom surface of the lower flange38to the top surface of the upper flange40is sufficiently smaller than the height of the case12from the top end of the annular rib22to the ceiling plate14A, such that axial direction movement of the reel28within the case12is possible. When the magnetic tape T is drawn-out or rewound, the reel28rotates in a state in which the reel28is moved upward with respect to the case12and is moved away from the annular rib22. Specifically, in the state in which the reel gear42is meshed together with the driving gear of the rotating shaft and the reel plate48is attracted to and held by the magnet without contacting the magnet, the reel28is driven to rotate around the axial center without contacting the case12while the reel28is raised up by the rotating shaft within the case12.

As shown inFIGS. 2A and 2B, the recording tape cartridge10is provided with a lock mechanism50which, when the magnetic tape T is not being used, restricts axial direction movement of the reel28and impedes rotation of the reel28with respect to the case12, and which, when the recording tape cartridge10is loaded in a drive device, permits rising-up and rotation of the reel28with respect to the case12. The structure of the lock mechanism50will be described in detail hereinafter.

As shown inFIG. 3, the lock mechanism50has the braking member52which serves as a rotation locking member. The braking member52has a disc portion54which is formed substantially in the shape of a disc. The braking gear56is provided at the outer peripheral portion of the bottom surface of the disc portion54, along the entire periphery thereof. Namely, the braking gear56is formed overall in an annular shape with the respective teeth thereof facing downward. The braking gear56can mesh with the engaging gear44of the reel28.

Plural (three in the present embodiment) guide portions58are provided at uniform intervals in the peripheral direction, on a top surface54A of the disc portion54in a vicinity of the outer periphery thereof. Each of the guide portions58is structured by a pair of guide walls58A. The pair of guide walls58A oppose one another across an imaginary line which coincides with the radial direction of the disc portion54. Restricting ribs60, which stand erect from the inner surface of the ceiling plate14A of the case12, slidingly enter-in between the guide walls58A of the respective guide portions58.

In this way, relative movement of the braking member52with respect to the case12, other than movement in the vertical direction, is restricted. Namely, rotation of the braking member52with respect to the case12is impeded, and the braking member52can move reciprocatingly in the vertical direction while being guided by the restricting ribs60at the respective guide portions58.

The braking member52is inserted and provided in the reel hub32(the cylindrical portion34) of the reel28, and the braking member52can be set at a rotation locking position (seeFIG. 2A) at which the braking gear56is meshed together with the engaging gear44which is provided at the floor portion36of the reel28which is set on the annular rib22, and a releasing position (seeFIG. 2B), at which the braking member52is moved away from the engaging gear44and releases the meshing-together of the engaging gear44and the braking gear56.

Due to rotation of the braking member52with respect to the case12being impeded, the braking member52impedes rotation of the reel28with respect to the case12when the braking member52is positioned at its rotation locking position, and when the braking member52is positioned at the releasing position, the braking member52permits rotation of the reel28with respect to the case12. Note that the releasing position is set as a position of the braking member52in the vertical direction (seeFIG. 7) such that the state in which the meshing-together of the braking gear56with the engaging gear44is released is maintained in the state in which the reel28is moved away from the annular rib22as described above. Namely, the braking member52, which is positioned at the releasing position, also permits movement of the reel28away from the annular rib22.

The release operation portion62, which is formed substantially in the shape of a hollow cylinder, projects from the axially central portion of the bottom surface of the disc portion54. An insert-through hole64is provided in the release operation portion62and the disc portion54, so as to pass through the respective axially central portions thereof and in the vertical direction. In the present embodiment, the upper side portion of the insert-through hole64has a larger diameter than that of the lower side portion thereof, and a step portion64A is formed therebetween. The outer diameter of the lower portion of the release operation portion62is smaller than the inner diameter of the pass-through hole46(the through hole48A) of the reel28.

Relief recesses66, which serve as relief portions which open upwardly at the top surface54A of the disc portion54, are provided in the disc portion54. The plural (three in the present embodiment) relief recesses66are provided at uniform intervals in the peripheral direction of the disc portion54. The respective relief recesses66are formed in substantially rectangular shapes in plan view, whose longitudinal directions run along central lines (the radial direction) passing through the peripheral direction intermediate portions between the guide portions58at the disc portion54. The one end portion of each relief recess66, which one end portion is near to the axial center of the disc portion54, is continuous with the insert-through hole64. Further, the longitudinal dimensions of the relief recesses66are determined such that the other end portions thereof are positioned at the inner side of an imaginary circle which connects the end portions (the inner edges) of the guide portions58which end portions are near to the axial center of the disc portion54. In this way, spacer portions74of the spacer member70which will be described later do not interfere with the guide portions58.

Stopper walls68stand erect from the top surface54A of the disc portion54, along one edge portions at the same side (the edge portion at the arrow C side inFIG. 3) in the transverse directions of the relief recesses66(the peripheral direction of the disc portion54). The length of each of the stopper walls68(the length thereof in the longitudinal direction of the relief recess66) is determined so as to not interfere with a compression coil spring82which will be described later.

The lock mechanism50has the spacer member70. The spacer member70has a base portion72which is formed substantially in the shape of a disc and which can be inserted in and removed from the insert-through hole64of the braking member52. The spacer portions74extend outwardly in the radial direction from the outer peripheral surface of the base portion72. The spacer portions74are provided at uniform intervals in the peripheral direction of the base portion72, and such that their longitudinal directions run along the radial direction of the base portion72. The spacer portions74are formed so as to be able to enter into respectively different ones of the relief recesses66. Further, as shown inFIG. 8as well, at each spacer portion74, the bottom portion of the surface facing toward the arrow D side is formed in a taper shape, so as to form a taper surface74A which is directed downwardly and toward the arrow D side. In the present embodiment, the heights (thicknesses) of the spacer portions74correspond to the depths of the relief recesses66.

In this way, the spacer member70can be set at a lock maintaining position (seeFIGS. 2A and 4), at which the bottom surfaces of the spacer portions74abut the top surface54A of the disc portion54at the braking member52, and a release preparation position (seeFIG. 5), at which the spacer portions74have entered into the respective relief recesses66. Further, a spacer wall76stands erect from the ceiling plate14A of the case12. A bottom end surface76A of the spacer wall76abuts the top surface of the base portion72of the spacer member70which is positioned at the lock maintaining position.

Namely, in the present embodiment, the spacer wall76corresponds to the ceiling plate in the present invention, and the spacer member70which is positioned at the rotation locking position fills in the gap between the braking member52and the spacer wall76, such that the spacer member70which is positioned at the release preparation position forms a gap G (seeFIG. 5) between the reel28and the spacer wall76. Further, in the present embodiment, the spacer wall76is formed in the shape of a cylindrical tube which is coaxial with the reel28(the annular rib22). Note that the outer diameter of the spacer wall76is sufficiently smaller than the diameter of an imaginary circle which connects the inner edges of the stopper walls68at the braking member52, so that the spacer wall76does not interfere with the stopper walls68of the braking member52which is positioned at the releasing position. Further, when the spacer member70is positioned at the release preparation position, the base portion72does not abut the step portion64A of the insert-through hole64.

A guide projection78, which is formed substantially in the shape of a solid cylinder, projects from the axially central portion of the top surface of the base portion72. The guide projection78is slidably inserted in a guide hole76B formed within the spacer wall76. In this way, the spacer member70moves upward and downward along the axis of the reel28while being guided by the spacer wall76, so as to be set at the lock maintaining position and the release preparation position. Further, the spacer member70can rotate relative to the case12in a state in which the spacer member70is centered by the spacer wall76.

The operation shaft portion80, which serves as an operation portion, projects from the bottom surface of the base portion72. The operation shaft portion80is formed in the shape of a solid cylinder which can be inserted through the insert-through hole64. A slot-shaped engagement groove80A is formed in the bottom end portion of the operation shaft portion80. In this way, the spacer member70is disposed between the ceiling plate14A and the braking member52, in a state in which the guide projection78is inserted in the guide hole76B of the spacer wall76and the operation shaft portion80is inserted in the insert-through hole64of the braking member52.

The lock mechanism50has the compression coil spring82which serves as an urging member and which urges the spacer member70downward. The compression coil spring82is disposed in a compressed state in which one end portion thereof abuts the ceiling plate14A and the other end portion thereof abuts the respective spacer portions74. An annular wall84, which is for preventing positional offset of the compression coil spring82, stands erect from the ceiling plate14A. The one end portion of the compression coil spring82is fit-together with and engages with the annular wall84.

In this way, the lock mechanism50urges the braking member52downward by the urging force of the compression coil spring82which is transmitted via the spacer member70, and pushes the reel28against the annular rib22by this urging force. Namely, as shown inFIG. 4, when the magnetic tape T is not in use, the lock mechanism50positions the braking member52at the rotation locking position and impedes rotation of the reel28with respect to the case12. Further, when the magnetic tape T is not in use, the lock mechanism50positions the spacer member70at the lock maintaining position.

In this state, because there is no gap in the vertical direction (the axial direction of the reel28) between the braking member52and the ceiling plate14A as described above, movement of the braking member52upward (toward the releasing position) is prevented, and the reel28is prevented from moving away from the annular rib22. Moreover, in this state, the release operation portion62of the braking member52is exposed to the exterior from the pass-through hole46(the through hole48A) of the reel28through the gear opening20, and the operation shaft portion80(the engagement groove80A) of the spacer member70is exposed to the exterior from the insert-through hole64of the release operation portion62. At this time, the braking member52and the spacer member70do not project out further than the bottom surface (the outer surface) of the floor plate16A of the case12.

On the other hand, when the magnetic tape T is to be used, first, the spacer member70moves from the lock maintaining position to the release preparation position. Specifically, due to the rotation of the operation shaft portion80in the direction of arrow C, the spacer portions74slide along the top surface54A of the disc portion54and are guided to positions above the relief recesses66, and due to the urging force of the compression coil spring82, the respective spacer portions74are made to enter into the respective relief recesses66. In this way, as shown inFIG. 5, the gap G is formed between the spacer wall76of the case12and the disc portion of the braking member52which is positioned at the rotation locking position. As shown in expanded views inFIGS. 8A and 8B, an angle of rotation θ of the spacer member70between the lock maintaining position and the release preparation position is substantially 60° in the present embodiment. Further, the stopper walls68prevent the spacer portions74from passing by above the relief recesses66such that movement to the release preparation position is not realized. Due to an unillustrated releasing member of the drive device rotating in the direction of arrow C in a state of engaging with the engagement groove80A, the operation shaft portion80is rotated in the direction of arrow C.

In this release preparation state, when the release operation portion62is pressed from beneath, as shown inFIG. 6, the braking member52is pushed upward against the urging force of the compression coil spring82and moves to the releasing position, such that the reel28can rotate with respect to the case12and can move away from the annular rib22. Accompanying the relative approach of the rotating shaft toward the reel28from below and the operation of the driving gear meshing with the reel gear42(the relative movement), the release operation portion62is pushed by a releasing projection provided at the axially central portion of the rotating shaft. The releasing projection is formed, for example, in the shape of a cylindrical tube so as to not interfere with the operation shaft portion80.

Then, the reel28is driven to rotate without contacting the case12, in the state in which the reel28is raised up as shown inFIG. 7due to the aforementioned relative movement while the rotating shaft meshes the driving gear together with the reel gear42. When the reel28is driven to rotate, the braking member52is held at the releasing position due to the state of abutment between the release operation portion62and the releasing projection being maintained.

When the rotating shaft moves away from the reel28(i.e., when the rotating shaft moves downward relatively), at the lock mechanism50, the reel28is pressed against the annular rib22due to the urging force of the compression coil spring, and the braking member52returns to the state of being positioned at the rotation locking position (the state shown inFIG. 5). Then, when, from this state, the operation shaft portion80is pushed upward until it abuts the spacer wall76, and rotates in the direction of arrow D, the spacer member70returns to the lock maintaining position (the state shown inFIG. 4). Further, when the spacer member70is rotated in the direction of arrow D, in a case in which the braking member52has not been lowered completely to the rotation locking position, the edge portions of the relief recesses66at the disc portion54(the edge portions at the arrow D side where the stopper walls68do not exist) are pressed by the taper surfaces74A of the spacer portions74, such that the braking member52reliably falls to the rotation locking position.

Next, operation of the present embodiment will be described.

At the recording tape cartridge10having the above-described structure, when the magnetic tape T is not in use, as shown inFIG. 4, rotation of the reel28, which is abutting the annular rib22(the floor plate16A) of the case12, with respect to the case12is impeded due to the braking gear56of the braking member52, which is positioned at the rotation locking position, meshing together with the engaging gear44. Further, the spacer member70is set (positioned), with substantially no gap, between the top surface54A of the braking member52and the spacer wall76of the case12, such that upward and downward movement of the braking member52is restricted.

Therefore, the upward and downward movement of the reel28also is restricted, and the reel28hardly joggles at all within the case12. In particular, in the present embodiment, joggling of the reel28is markedly suppressed because the braking member52is pressed against the reel28due to the urging force of the compression coil spring82and the reel28is pressed against the annular rib22.

At this time, the reel gear42and the reel plate48of the reel28are exposed from the gear opening20, and the release operation portion62of the braking member52and the operation shaft portion80of the spacer member70are exposed from the pass-through hole46of the reel28. Further, the opening18is closed by the leader block30.

On the other hand, when the magnetic tape T is to be used, the recording tape cartridge10is loaded into a bucket (not illustrated) of the drive device along the direction of arrow A. When the recording tape cartridge10is loaded to a predetermined depth in the bucket, the releasing member of the drive device engages with the engagement groove80A of the spacer member70, and rotates substantially 60° in the direction of arrow C. Then, when the releasing member comes out from the engagement groove80A, the spacer portions74enter into the relief recesses66due to the urging force of the compression coil spring82. Namely, as shown inFIG. 5, the spacer member70moves to the release preparation position, and the gap G is formed between the top surface54A of the braking member52and the spacer wall76of the case12.

From this state, the bucket is lowered, and the rotating shaft of the drive device relatively approaches the gear opening20of the case12(relatively moves upward) and holds the reel28. Specifically, the drive gear of the rotating shaft meshes together with the reel gear42while the rotating shaft attracts and holds the reel plate48in a non-contact state by the magnet.

Accompanying the meshing together of the reel gear42and the driving gear, i.e., the relative movement of the rotating shaft (adjacent side) in the axial direction toward the case12, the releasing projection of the rotating shaft pushes the braking member52upward against the urging force of the compression coil spring82. In this way, the meshing-together of the braking gear56and the engaging gear44is cancelled. Namely, as shown inFIG. 6, the braking member52moves to the releasing position. At this time, the spacer member70, whose spacer portions74are within the relief recesses66, moves upward together with the braking member52.

Then, as shown inFIG. 7, the reel28is raised upward within the case12by the rotating shaft which moves relative to the case12as described above, and the reel28becomes able to rotate with respect to the case12in a state of non-contact in which the reel28is moved apart from the annular rib22. This series of operations is carried out as the bucket, i.e., the recording tape cartridge10, is lowered by a predetermined amount within the drive device.

Further, due to the lowering of the bucket, the positioning pins of the drive device respectively enter into the positioning holes24,26of the case12, and the positioning surfaces of the drive device abut the positioning surfaces24A,26A of the case12. The recording tape cartridge10is thereby positioned in the horizontal directions and in the vertical direction with respect to the drive device. Thus, while a pull-out pin (not illustrated) of the pull-out means of the drive device engages with the engaging recess30A of the leader block30, the pull-out means pulls the leader block30out from the case12and guides the leader block30to the take-up reel of the drive device. The leader block30is fit into the take-up reel such that the arc-shaped surface30B structures a portion of the take-up surface around which the magnetic tape T is taken-up.

In this state, when the leader block30rotates integrally with the take-up reel, the magnetic tape T is pulled-out from the case12through the opening18while being taken-up onto the reel hub of the take-up reel. At this time, the reel28of the recording tape cartridge10rotates synchronously with the tape-up reel, due to the torque of the rotating shaft which is transmitted by the driving gear which meshes with the reel gear42. Information is recorded onto the magnetic tape T or information recorded on the magnetic tape T is played back by a recording/playback head disposed along a predetermined tape path of the drive device. At this time, the release operation portion62of the braking member52, which cannot rotate with respect to the case12, holds the braking member52at the releasing position while slidingly-contacting the releasing projection of the rotating shaft which drives and rotates the reel28.

On the other hand, when the magnetic tape T is rewound onto the reel28and the leader block30is held in a vicinity of the opening18of the case12, the bucket in which the recording tape cartridge10is loaded is raised. Thus, the reel28and the braking member52move downward relative to the case12while being supported by the driving gear and the releasing projection of the rotating shaft, respectively. When the reel28abuts the annular rib22and further lowering of the reel28is impeded, the meshing of the reel gear42and the driving gear is cancelled. When the braking gear56of the braking member52meshes together with the engaging gear44and further downward movement of the braking member52is impeded, the braking member52is set apart from the releasing projection. In this way, the supporting of the urging force of the compression coil spring82by the releasing projection ceases to exist, and due to this urging force, the braking member52is pressed against the reel28and the reel28is pressed against the annular rib22.

Accompanying the relative lowering of the braking member52with respect to the case12, the spacer member70is lowered together with the braking member52while the spacer portions74remain within the relief recesses66, and as shown inFIG. 5, the spacer member70returns to the release preparation position. Namely, in this state, the gap G is formed between the spacer wall76and the top surface54A of the braking member52. The bucket stops when raised by a predetermined amount (an amount equal to the amount by which it was lowered).

From this state, the releasing member of the drive device enters into the engagement groove80A of the spacer member70, and first, moves upward and pulls the spacer portions74out from the relief recesses66. Then, the releasing member rotates substantially 60° in the direction of arrow D, so as to position the spacer portions74on the top surface54A of the disc portion54. Namely, the spacer member70is returned to the lock maintaining position. In this way, the recording tape cartridge10(the lock mechanism50) returns to the initial state in which rotation of the reel28with respect to the case12and axial direction movement of the reel28are impeded. In this state, the recording tape cartridge10is ejected from the bucket (the drive device) in the direction opposite to arrow A.

Here, the spacer member70, which fills-in the gap G between the ceiling plate14A and the braking member52when the recording tape cartridge10is not in use, is provided. Therefore, when the recording tape cartridge10is not in use, the reel28does not move greatly in the axial direction within the case12. Accordingly, for example, even if force in the axial direction were to be applied to the reel28due to the impact of a drop or an erroneous operation such as the reel plate48being pushed or the like, the magnetic tape T wound on the reel28is protected. Further, because vertical direction movement of the braking member52, together with that of the reel28, within the case12is restricted, it is also possible to prevent the locking of the rotation of the reel from being released due to the aforementioned impact of a drop or the like. Therefore, it is possible to prevent the reel28from rotating and tightening or loosening of the winding of the magnetic tape T from occurring at the time of a drop.

The relief recesses66(the insert-through hole64), into which the spacer portions74(the base portion72) of the spacer member70enter, are provided in the braking member52. Therefore, by a small movement stroke, the spacer member70forms the gap G (is pulled out from the gap G) and permits movement of the braking member52toward the ceiling plate14A. Therefore, the function of, at the time when the recording tape cartridge10is to be used, canceling the state in which movement of the reel28in the axial direction is impeded, can be realized by a relatively compact structure.

Due to the operation shaft portion80, which is provided integrally with the spacer member70, being rotated in the direction of arrow C, the spacer member70rotates in the direction of arrow C, and the spacer member70moves from the lock maintaining position to the release preparation position at which the spacer portions74are within the relief recesses66. Therefore, the function of, at the time when the recording tape cartridge10is to be used, canceling the state in which movement of the reel28in the axial direction is impeded, can be realized by a relatively simple structure. In particular, the plural (three) spacer portions74, which are disposed at uniform intervals in the peripheral direction, enter into the respective relief recesses66due to the operation of the single operation shaft portion80. Therefore, with a simple structure, the function of, at the time when the recording tape cartridge10is to be used, canceling the state in which movement of the reel28in the axial direction is impeded, can be realized while achieving the function of stably impeding vertical direction movement of the reel28and the braking member52when the recording tape cartridge10is not in use.

In this way, in the recording tape cartridge10relating to the present embodiment, the reel28can be prevented from moving greatly in the axial direction within the case12at times when the recording tape cartridge10is not in use.

Note that, in the above-described embodiment, the lock mechanism50is structured so as to have the compression coil spring82. However, the present invention is not limited to the same. For example, in a structure in which the recording tape cartridge10is used in a horizontal drive device (a drive device into which the recording tape cartridge10is loaded with the axis of the reel28coinciding with the vertical direction), it is possible to not provide the compression coil spring82. In this case, the urging force of the compression coil spring82is not applied to the region of sliding contact between the release operation portion62of the braking member52and the releasing projection of the rotating shaft when the reel28is driven to rotate, and wear of this region of sliding contact can be prevented or markedly suppressed.

Further, the above-described embodiment is a preferable structure in which the spacer portions74of the spacer member70rotate around the axial center of the base portion72and enter into the relief recesses66. However, the present invention is not limited to the same. For example, the spacer member70may be structured to move between the lock maintaining position, at which the spacer member70fills-in the gap G, and the release preparation position, at which the spacer member70is pulled-out from the gap G, by moving in the radial direction of the reel28. Namely, the present invention is not limited by the above-described preferable structures (configurations) of the braking member52, the spacer member70, the spacer wall76, and the like. Accordingly, for example, in place of the structure in which the spacer member70is exposed from the gear opening20of the case12and is operated by the drive device, for example, the spacer member70may be exposed from a window portion provided in the forward-facing peripheral wall14B so as to be operated by the drive device as the recording tape cartridge10is loaded into the bucket in the direction of arrow A.

Moreover, the above-described embodiment is structured such that the relief recesses66, into which the spacer portions74enter such that the gap G is formed, are provided in the braking member52. However, the present invention is not limited to the same. For example, a structure may be used in which relief portions which open downwardly are provided in the spacer wall76(the ceiling plate14A). As the braking member52moves to the releasing position, the spacer portions74of this structure move upward together with the braking member52and enter into the relief portions. As the braking member52moves to the rotation locking position, these spacer portions74move upward together with the braking member52and are pulled-out from the relief portions. Therefore, in other words, the movement between the lock maintaining position and the release preparation position is achieved merely by motion (rotation) within a plane running along the top surface54A. Therefore, there is no need for the spacer member70to move upward and downward independently of the braking member52, and the releasing member of the drive device can be made to be simple. Moreover, the relief portions at the braking member52or the spacer wall76are not limited to the relief recesses66which are concave portions, and may be, for example, cut-outs or holes which pass through the disc portion54in the direction of plate thickness. Further, it goes without saying that the present invention is not limited by the absence/presence of, the configuration of, and the like of the spacer wall76.

The above-described embodiment is structured such that rotation of the reel28is impeded by the braking gear56of the braking member52meshing together with the engaging gear44which is provided at the floor portion36of the reel hub32. However, the present invention is not limited to the same. For example, a structure may be used in which the open end of the cylinder portion34is formed in a tapered shape, and the engaging gear44in the form of internal teeth is formed at this tapered surface, and the braking member52is set at the rotation locking position and the releasing position by moving in the radial direction of the reel28.

In addition, the above-described embodiment is structured such that, after the operation shaft portion80is pushed upward, the operation shaft portion80rotates in the direction of arrow D and returns the spacer member70to the lock maintaining position. However, the present invention is not limited to the same. For example, a structure may be used in which the heights of the spacer portions74are formed to be greater than the depths of the relief recesses66, and taper surfaces74A are formed over the entire heights of the spacer portions74, and the spacer member70rides up on the top surface54A of the disc portion54merely by rotating in the direction of arrow D.

In the above-described embodiment, the recording tape cartridge10is a so-called single-reel recording tape cartridge in which the single reel28is accommodated within the case12. However, the present invention is not limited to the same, and, for example, may be a structure in which the lock mechanism50is provided at one or both of the reels structuring a two-reel recording tape cartridge which accommodates two of the reels28(for drawing-out and taking-up).

Further, the magnetic tape T is used as the recording tape in the above-described embodiment. However, the present invention is not limited to the same. It suffices for the recording tape to be interpreted as an information recording/playback medium which is shaped as an elongated tape and on which information can be recorded and from which recorded information can be played back. It goes without saying that the recording tape cartridge relating to the present invention can be applied to recording tapes of any recording/playback systems.