JP2567783Y2 - Magnetic tape cassette - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic tape cassette, and more particularly to a digital audio tape (D).
AT) A digital magnetic tape cassette such as a cassette.

[0002]

2. Description of the Related Art In recent years, cassette tape recorders have been reduced in size and weight, and magnetic tape cassettes used for such tape recorders have also been reduced in size. There has been a strong demand for magnetic tapes that can be used for high-density recording and reproduction. In order to meet such a demand, a digital signal such as pulse code modulation (PCM) is known for an input signal, unlike an analog method. At present, a recording frequency band using this method is known. DAT cassettes that can be as large as several times the size of analog audio tapes are widely used. This DA
The T cassette employs a rotating head system, and has a guard panel that closes an opening provided at the front of the cassette and can be opened above the cassette.

In the case of using this digital system, recording and reproduction in a high-density and wide frequency band having a shorter recording wavelength than that of a conventional compact cassette for audio are performed, so that a tape protection measure with improved reliability is sufficiently taken. Required a cassette structure. The DAT cassette is a magnetic tape cassette which is extremely small in size as compared with an analog audio compact cassette. Therefore, since the DAT cassette is expected to be carried outdoors more frequently than or equal to the conventional audio compact cassette, the tape caused by the tape loosening caused by the vibration given to the cassette by carrying or the like. A structure that can reliably prevent jamming is required. Therefore, the DAT cassette includes a hub brake member that locks and releases the hub around which the magnetic tape is wound when not in use and when in use. The hub brake member is always urged in the direction of the hub by a spring. When not in use, the pointed protrusion provided on the hub brake member abuts on the hub to prevent rotation of the hub and when used, the pointed protrusion is formed. It is structured to be separated from the hub.

[0004]

A structure for preventing the tape wound around the hub from being loosened is disclosed in Japanese Utility Model Publication No. 2-49031, for example.
In the disclosed structure, the pointed protrusion 41 of the hub brake member 40 enters into and engages with the tooth valley of the hub gear 15 as shown in FIG.
Are engaged at positions shifted outward from the hub center. The configuration is such that the hub is urged in the tightening direction (the direction C in the drawing) of the magnetic tape by eccentric engagement such as the pointed protrusion 41 so as to reduce any looseness of the tape.

However, even in such a configuration, a gap W is formed between the hub gear 15 and the pointed protrusion 41 in the loosening direction (the direction D in the drawing). Further, even when the pointed protrusions 41 are engaged, the magnetic tape stretched between the hubs is not always in a tight state. Therefore, it was not possible to completely prevent the hub from rattling due to the gap W. Due to this gap, the magnetic tape becomes slack due to vibration when carrying or in severe use conditions,
Tape jamming may occur or the magnetic tape may be damaged by contact with other components. The present invention has been made in view of the above problems, and has a reliable hub locking function that can lock not only the tape loose direction side but also the tightening direction side by the sharp protrusion of the hub brake member. It is an object of the present invention to provide a magnetic tape cassette having the same.

[0006]

According to the present invention, a pair of hubs each having a magnetic tape wound thereon are provided with hub gears on the outer periphery at one end thereof, and a pair of pointed projections engaged with the respective hub gears are provided. In a magnetic tape cassette provided with a hub brake member mounted and slidably mounted in the front-rear direction of the cassette and urged rearward by a spring member,
The tip of the pointed projection engages with the tooth side surface constituting the effective height of the tooth space of the hub gear, and one side of the pointed projection contacts the tooth surface opposite to the tooth surface contacted by the tip. This can be achieved by a magnetic tape cassette characterized in that it is configured to perform the following. Further, the angle α of the tip of the pointed projection is
The above object is also achieved by a magnetic tape cassette configured to be smaller than an angle β formed between an extension of the tooth surface of the tooth space and a tangent drawn from the upper end of the effective height portion of the tooth surface to the adjacent tooth surface. can do.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an enlarged schematic perspective view showing main components of the magnetic tape cassette of the present invention, and FIG. 2 is a schematic plan view of a main part illustrating an engagement state between a pointed portion of a hub brake member of the present invention and a hub gear. FIG. 3 is an explanatory view showing the relationship between the shape of the pointed protrusion and the tooth groove of the hub gear. In FIG. 1, a magnetic tape cassette 1 has a pair of hubs around which a magnetic tape 50 is wound in a case body constituted by an upper cassette half 11 and a lower cassette half 12.
The hub 14 is rotatably mounted corresponding to a pair of shaft insertion holes (not shown) formed on the bottom surface of the lower cassette half 12 as is well known. The shaft insertion hole is provided in the lower cassette half 12.
It is configured to be opened by the movement of a slider 3 slidably provided along the bottom surface of the. At the front of the cassette, a guard panel 10 which is a front cover that is rotatable (arrow E) about a support shaft provided at the side end 26 is attached.

A pair of pointed projections 22 are provided on the body 21 of the hub brake member 20 mounted in the magnetic tape cassette 1 so as to project toward the rear of the cassette corresponding to the hub 14. In addition, an operating section 23 extending toward the front of the cassette is provided on the leg portions at both ends of the body section 21. The body portion 21 is pushed rearward of the cassette (in the direction A) by a spring 32 which is locked so as to wind around a fixed boss 31 protruding from the inner surface of the upper cassette half 12. ing. The hub brake member may be appropriately held on both sides of the body portion 21 by, for example, a guide member (not shown) on the inner surface of the cassette.
Numeral 20 can slide along the inner surface of the upper cassette half 11 in the front-rear direction (A and B directions) of the cassette without play.

Therefore, when the magnetic tape cassette 1 is not used, the hub brake member 20 is located at the hub locking position by the spring 32, and the pointed projections 22 are It is engaged with the hub gear 15. The slider 13 is also biased toward the front of the cassette by an appropriate spring (not shown), and is located at the front of the cassette to close the lower surface of the cassette. Here, when the magnetic tape cassette 1 is loaded into the recording / reproducing apparatus, the slider 13 is pushed and moved to the rear of the cassette, and the guard panel 10 is opened (the opening direction of arrow E).
Due to the opening movement of the guard panel 10, the side end 26 of the guard panel 10 is engaged with the operating portion 23 of the hub brake member 20, and the hub brake member 20 is moved forward of the cassette (in the direction B) by the spring 32. Moved against the urging force, the locking of the hub gear 15 by the pointed projection 22 is released.

Next, an engagement state between the pointed protrusion 22 and the hub gear 15 will be described with reference to FIG. FIG. 2 shows only a portion corresponding to the hub gear on the left side of FIG. The two-pointed protruding portions 22 are provided outside the respective rotation centers 4 of the hub gear 15 (
(A position closer to the outside in the cassette left-right direction). The pointed projection 22 has an inclined surface 19 at a tip portion thereof, and is appropriately formed in a wedge shape having an angle α. When the pointed protrusion 22 is engaged with the hub gear 15, the tip of the pointed protrusion 22 is
Engaged with the tooth side surface 17 that constitutes the effective height of the tooth space,
The tooth surface where the inclined surface 19 is opposed to the tooth surface with which the tip is in contact (
It is configured so as to contact a tooth (counterclockwise direction side in the figure). Thus, the hub brake member 20
The tip 22 applies a force that pushes the hub 15 in the direction of tightening the magnetic tape 50, while the inclined surface 19 comes into contact with the opposite tooth surface across the tooth groove. This prevents the magnetic tape 50 from moving in both the loosening direction and the tightening direction of the magnetic tape 50.
The movement of the hub 15 can be reliably prevented.

Further, as shown in FIG. 3, the angle α of the tip of the pointed projection 22 is defined by the extension 60 of the tooth surface 17 of the tooth space and the adjacent tooth surface from the upper end 27 of the effective height portion of the tooth surface 17. It is configured to be smaller than the angle β formed by the drawn tangent line 70. The effective height portion upper end 27 of the tooth side surface 17 referred to herein is the hub gear 15
At the maximum height of the tooth surface excluding the chamfered and rounded tip portion 28 of each tooth. Further, the effective height portion referred to here is a portion corresponding to the tooth side surface 17 excluding the tip portion 28 and the tooth bottom 16. Therefore, the tip portion
If you have a square tooth shape with no curved parts as shown in 28,
The corner, which is the top of the tooth, is the upper end of the effective height of the tooth surface 17. According to the relationship of angle α <β as described above, the inclined surface 19 contacts the tooth surface while
Can reliably engage with the tooth side surface 17, and the hub locking action of the pointed projection 22 can be further ensured.

[0012]

As described above, according to the present invention, the tip of the pointed protrusion of the hub brake member is engaged with the tooth side surface which constitutes the effective height of the tooth space of the hub gear, and one of the pointed protrusions is provided. The side surface is configured to contact a tooth surface opposite to the tooth surface with which the tip contacts. Therefore, the tip of the pointed portion applies a force to push the hub in the direction of tightening the magnetic tape, while the side surface of the pointed portion contacts another tooth surface. The tape is locked so that it cannot move in both the loosening direction and the tightening direction, and even if the magnetic tape cassette receives vibration or impact, unexpected movement of the hub can be reliably prevented. As a result, according to the present invention,
A magnetic tape cassette having a reliable hub locking function can be provided.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic perspective view showing main components of the magnetic tape cassette of the present invention.

FIG. 2 is a partial plan view showing an engagement state between a pointed portion of the hub brake member of the present invention and a hub gear.

FIG. 3 is a schematic explanatory view showing a tip shape of a pointed protrusion of the hub brake member according to the present invention;

FIG. 4 is a partial plan view illustrating a state in which a sharp projection of a conventional hub brake member is engaged with a hub gear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic tape cassette 10 Guard panel 11 Upper cassette half 12 Lower cassette half 13 Slider 14 Hub 15 Hub gear 16 Teeth bottom 17 Teeth side surface 19 Inclined surface 20 Hub brake member 21 Body part 22 Pointed protrusion 23 Operation part 26 Side end 28 Front end Part 32 Spring C Rotation direction of hub tightening D Rotation direction of hub loosening

Claims (2)

(57) [Scope of request for utility model registration] A pair of hubs on which a magnetic tape is wound are provided with hub gears on the outer periphery at one end side, and have a pair of pointed projections that engage with the respective hub gears and are slidably mounted in a cassette longitudinal direction. In a magnetic tape cassette provided with a hub brake member biased rearward by a spring member, the tip of the pointed protrusion engages with a tooth side surface constituting an effective height of a tooth groove of the hub gear, and A magnetic tape cassette, wherein one side surface of the pointed projection is configured to contact a tooth surface opposite to a tooth surface with which the tip contacts. 2. The angle α at the tip of the pointed projection is defined by the angle β formed between an extension of the tooth surface of the tooth space and a tangent drawn from the upper end of the effective height portion of the tooth surface to the adjacent tooth surface. 2. The magnetic tape cassette according to claim 1, wherein said magnetic tape cassette is also made smaller.