JPH0677074U - Magnetic tape cassette - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the occurrence of defective molding of the brake device in a magnetic tape cassette. [Structure] The tape winding hub 41 is provided on the back surface of the upper half 1.
A brake member 3 having a braking piece 31 that engages with a gear 42 integrally formed with the brake member 3 is slidably guided within its movement range, and the upper half 1 of the brake member 3 is also guided.
A substantially transparent brake member guide member 9 having a pair of guide protrusions 91 that engages with a fall prevention engagement protrusion 33 for preventing the brake member from coming off is provided in close contact. By setting the thickness of the engaging protrusion 33 for preventing the brake member 3 from falling off to be large, defective molding of the upper half 1 can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cassette, and more particularly to an improvement of a fall prevention structure of a brake device provided to prevent slack when a magnetic tape contained in a magnetic tape cassette is conveyed.

[0002]

[Prior art]

 As is well known, in a magnetic tape cassette, a pair of take-up hubs or take-up reels around which the ends of a long magnetic tape are fixed and then the magnetic tape is wound are provided between the two hubs. It is housed in a case (harf) that exposes only the stretched magnetic tape portion. Furthermore, in order to protect the magnetic layer surface of the magnetic tape, the closed position that covers the magnetic tape in the portion exposed by this half and this magnetic It has a lid that is movably supported between an open position that exposes the tape and a spring-biased lid that is in the closed position.

In this magnetic tape cassette, the lid is moved to the open position in synchronization with loading into the recording / reproducing apparatus, and when one winding hub or the like is rotated, the magnetic tape is removed from the other winding hub or the like. Information is recorded on the magnetic tape or reproduced from the magnetic tape by an operation of bringing a magnetic head or the like of a recording / reproducing device into contact with the exposed tape that has been sent out.

By the way, the magnetic tape wound around the winding hub may be loosened due to vibration during transportation, and may be gradually squeezed out of the cassette to cause slack between the two winding hubs. When the slackened tape is loaded into the recording / playback device as it is, the slackened tape becomes entangled with the pinch rollers of the recording / playback device or other tape suspension members, causing the recording / playback device to malfunction or the tape to stretch. There is also something to do.

Therefore, a magnetic tape cassette equipped with a brake device that reliably stops the rotation of the hub when the tape is not in use has been developed. For example, a breaking device used for a DAT cassette or the like is a pair of winding magnetic tapes. Gears integrally formed on the upper end surface of the hub coaxially with the hub, a braking position that engages with the gears to prohibit rotation of the hub in the winding loosening direction, and the gear is disengaged from the gears to remove the hub. It is movable between a release position that allows rotation of the lid, spring-biased to the braking position, and the lid is rotated to the open position in conjunction with loading into the recording / playback device. The structure is provided with a brake member that is moved to the release position by a protrusion that is partly provided.

Further, in the magnetic tape cassette provided with this brake member, the brake member can be smoothly moved between the braking position and the releasing position on the back surface of one of the halves thereof, and the convenience of the magnetic tape cassette is improved. Therefore, a brake member guide portion for locking the brake member to the back surface of one half is provided. For example, the brake member guide portion is integrally formed with a transparent window member that covers the opening provided in the upper half for confirming the running state of the magnetic tape, and is closely provided on the back surface of the upper half. . There is also a mode in which the brake member guide portion is also used as the window member. Further, it has a guide protrusion formed in an overhang shape on the back surface of the upper half, and a fall prevention portion formed on the brake member is engaged between the guide protrusion of the overhang shape and the back surface of the upper half. This makes the movement of this brake member smooth.

[0007]

[Problems to be solved by the device]

 By the way, the halves, brake members, and brake member guides that compose the magnetic tape cassette are made of resin material from the viewpoint of weight reduction and prevention of influence on the magnetic tape. Since the part is engaged with a narrow gap formed between the half and the window part or between the half and the brake member guide part integrally formed in the window part, the thickness thereof is extremely small. There is a problem in terms of thinness and formability. That is, if it is attempted to thinly form the drop-out preventing portion with a resin material, a molding defect such as so-called short-circuit or deformation may occur, resulting in a decrease in productivity.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a magnetic tape cassette including a breaking device that reduces the occurrence of defective molding.

[0009]

[Means for Solving the Problems]

 In the magnetic tape cassette of the present invention, by providing a groove on the back surface of the half that faces the overhang-shaped guide protrusion of the brake member guide portion, the distance between the guide protrusion and the back surface of the half is increased. The thickness of the fall prevention portion of the brake member that is engaged between the guide protrusion and the rear surface of the half can be set thicker to prevent molding failure of the fall prevention portion.

That is, as described in claim 1, the magnetic tape cassette has a half for housing a pair of take-up hubs formed by winding a magnetic tape, and the take-up hub engaged with the half. A braking member that is freely movable between a braking position that prohibits rotation in the winding slack direction and a release position that allows rotation by separating from the winding hub. A guide protrusion is formed in an overhang shape on the rear surface of the half, and a fall prevention portion of the brake member is engaged between the overhang-shaped guide protrusion and the rear surface of the half. In a magnetic tape cassette in which a brake member guide portion is slidably guided in a moving direction, a portion of the back surface of the half that faces the guide protrusion of the brake member guide portion is the brake. It is characterized in that it has a groove extending in the moving direction of the member, and the thickness of the fall prevention portion of the brake member has a size to fit into this groove.

Here, the brake member guide portion densely provided in the half may be a separate object partially having the brake member guide portion densely provided in the half, or It may be formed as a part of the half.

[0012]

According to the magnetic tape cassette of the present invention, the back surface of the half and the above-mentioned guide projection are provided by providing a groove on the back surface of the half opposite to the overhang-shaped guide projection of the brake member guide. The distance between and can be increased by the depth of the groove in the conventional magnetic tape cassette having no groove. As a result, the thickness of the slip-off preventing portion of the brake member that engages between the guide protrusion of the brake member guide portion and the rear surface of the half, that is, the groove can be set thick.

As described above, according to the magnetic tape cassette of the present invention, the groove is formed on the back surface of the half to substantially increase the interval between the engaging portions of the slip-off preventing portion of the brake member, and accordingly. As a result, the thickness of the fall-preventing portion of the brake member can be increased to reduce defective molding of the fall-preventing portion.

[0014]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective exploded view showing a schematic configuration of a magnetic tape cassette according to the present invention, FIG. 2 (a) is a perspective plan view of the magnetic tape cassette shown in FIG. 1, and (b) is shown in (a). It is sectional drawing which shows the BB line cross section of the magnetic tape cassette. The illustrated magnetic tape cassette accommodates a pair of hub bodies 4 on which a magnetic tape 5 is wound by an upper half 1 and a lower half 2 and a portion of the magnetic tape 5 stretched between the hub bodies 4. Is exposed from half 1 and 2. On the upper half 1, a spring-biased lid 6 is pivotally supported at the closed position so as to be movable between a closed position for covering the exposed magnetic tape 5 and an open position for exposing the magnetic tape 5. The half 2 is provided with a slider 7 slidably between a position covering the space on the back side of the magnetic tape 5 in a portion stretched between the hub bodies 4 and a position exposed.

Specifically, the hub body 4 is composed of a hub 41 around which the tape 5 is wound, and a gear 42 which is coaxially formed with the hub 41 and integrally formed on the upper end surface of the hub 41. Further, this magnetic tape cassette is provided with a brake member 3 having two braking pieces 31 which respectively engage with the gears 42 of the respective hub bodies 4, and this brake member 3 is used in a recording / reproducing apparatus not shown in the magnetic tape cassette. At the time of non-loading, the pair of braking pieces 31 engage with the gears 42 facing each other and are spring-biased by the spring 3a to the braking position for inhibiting the rotation of the hub body 4. On the other hand, at the time of loading on the recording / reproducing apparatus, the lid is loaded. By rotating 6 in the direction of arrow K by the recording / reproducing device, the hook portion 32 is hooked by the projection 6a provided on the side plate 62 of the lid 6 and pulled in the direction of the lid 6, and the braking piece 31 becomes a gear. It is configured to be separated from 42 and moved to a release position that allows rotation of the hub body 4 (see FIG. 2 (a)).

Further, the upper half 1 is provided with an opening 1a for externally checking the running state and the remaining amount of the magnetic tape 5, and the opening 1a is a window member which is substantially transparent from the inner surface of the upper half 1 to prevent dust. Blocked by 8. The window member 8 guides the brake member 3 slidably within its movement range, and a fall prevention engagement projection 33 for preventing the brake member 3 from dropping from the upper half 1. It is integrally joined with a substantially transparent brake member guide member 9 having a pair of guide protrusions 91 that engage with each other, and the brake member guide member 9 is in close contact with the back surface of the upper half 1.

The engagement state of the brake member guide member 9, the upper half 1 and the brake member 3 will be described in detail as shown in the sectional view taken along the line BB of FIG. 2A (FIG. 2B). Movement of the brake member 3 formed on the rear surface of the upper half 1 opposite to the guide protrusion 91 of the brake member guide member 9 formed in an overhang shape with respect to the rear surface (inner surface) of the upper half 1. Between the groove 1b extending in the direction (the arrow X direction in FIG. 2 (a)) and the guide protrusion 91 of the brake member guide member 9 and having a thickness similar to the gap therebetween. The engaging projection 33 for preventing the falling is engaged.

As described above, in the magnetic tape cassette of the present invention, the thickness of the engaging projection 33 for preventing the brake member 3 from falling off can be set to a large value. Can be reduced.

In the magnetic tape cassette of the present invention, the engagement protrusion 33 for preventing the brake member 3 from falling out does not need to extend long in the moving direction of the brake member 3 as in the above embodiment. The small protrusion 34 may be short in the moving direction of the brake member 3, as shown in FIG.

[Brief description of drawings]

FIG. 1 is a perspective exploded view showing a schematic configuration of a magnetic tape cassette according to the present invention.

2A is a perspective plan view of the magnetic tape cassette shown in FIG. 1, and FIG. 2B is a sectional view showing a cross section taken along line BB of the magnetic tape cassette shown in FIG.

FIG. 3 is a perspective view of a main part showing another embodiment of the magnetic tape cassette according to the present invention.

[Explanation of symbols]

 1 Upper half 1a Opening 1b Groove 2 Lower half 3 Brake member 3a Spring 4 Hub body 5 Magnetic tape 6 Lid 6a Protrusion 7 Slider 8 Window member 9 Brake member guide member 31 Braking piece 32 Hook portion 33 Falling prevention engagement protrusion 34 Small protrusion 41 Hub 42 Gear 62 Side plate 91 Guide protrusion

Claims (1)

[Scope of utility model registration request] 1. A half for accommodating a pair of winding hubs formed by winding a magnetic tape, and a braking position which engages with the winding hub and prohibits rotation of the winding hub in a winding loosening direction. A brake member which is detachable from the take-up hub and is movable between a release position allowing the rotation of the take-up hub, and an overhang shape on the back surface of the half. A guide protrusion is formed, and a fall prevention portion of the brake member is engaged between the overhang-shaped guide protrusion and the back surface of the half to guide the brake member slidably in the moving direction. In a magnetic tape cassette in which brake member guide portions are densely arranged, a portion of the back surface of the half that faces the overhang-shaped guide protrusion of the brake member guide portion has a groove extending in the moving direction of the brake member. Have the above Magnetic tape cassette thickness of the disengagement prevention part of over key member is characterized in that it has a size that fits into the groove.