JP2582297Y2 - Tape cassette - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cassette,
In particular, the present invention relates to a structure for clamping a tape terminal portion to a hub. FIG. 4 shows a tape cassette generally called a microcassette. In the figure, reference numeral 1 denotes a cassette housing, and a pair of hubs 2 and 2 are rotatably housed in the cassette housing 1, and a magnetic tape T is fixed to a terminal portion on a peripheral surface of the hub 2. It is wound in a state. A lock pin is used for fixing (clamping) the end of the magnetic tape T to the hub 2 as shown in FIG. That is, the hub 2 has a recess 3 having a narrow opening.
The metal tape T is clamped to the hub 2 by press-fitting a metal lock pin 4 into the recess 3 with the terminal of the magnetic tape T interposed therebetween. [0004] In the hub 2 having such a tape clamp structure, a gap (step) 5 is formed between the opening of the recess 3 and the lock pin 4 as is clear from FIG. For this reason, when the tape is stored in a tape wound state, the step shape due to the gap 5 is transferred to the magnetic tape T (FIG. 8).
This causes dropout of the recording signal. Further, it is difficult to form the concave portion 3 of the hub 2 into a perfect circular shape exactly corresponding to the cross section of the lock pin 4, and FIG.
As shown in FIG. 5, the lock pin 4 is actually formed into a slightly distorted shape (in this figure, the distorted shape of the concave portion 3 is exaggerated), so that the lock pin 4 does not completely adhere to the inner surface of the concave portion 3.
That is, since the contact area between the lock pin 4 and the concave portion 3 is small, there is a possibility that a sufficient clamping force of the magnetic tape T cannot be secured. [0006] The present invention has been made in view of such a point,
It is an object of the present invention to provide a tape clamp structure in which a step shape is not transferred to a tape and a sufficient tape clamping force can be obtained by considering a dimensional relationship between a molding material of a lock pin and a concave portion. [0007] In order to achieve the above object, the present invention has a pair of hubs for winding a tape around a cassette housing in a rotatable manner, and a recess formed in the hub. In a tape cassette in which a lock pin is fitted to fix a terminal portion of a tape to a hub, a flexible polyamide resin capable of deforming the lock pin so as to absorb a gap with an opening of a concave portion. The comb is formed from a polyurethane resin so as to be non-hollow, and the inner diameter of the recess is smaller than the outer diameter of the lock pin. According to the above construction, when the lock pin is press-fitted into the recess, the lock pin is deformed to absorb the gap between the lock pin and the opening of the recess. Further, since the lock pin is deformed so as to follow the shape of the concave portion, the lock pin is completely adhered to the inner surface of the concave portion, thereby securing a sufficient tape clamping force. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3, and portions corresponding to those of the above-described conventional example will be denoted by the same reference numerals and description thereof will be omitted. In this embodiment, first, a resin (for example, polyamide or polyurethane) having flexibility and generating a repulsive force by compression is used as a molding material of the lock pin 4 instead of a conventional metal. The inner diameter of the recess 3 into which the lock pin 4 is fitted is formed smaller than the outer diameter of the lock pin 4. For reference, the actual dimensions of the lock pin 4 and the recess 3 are described as follows. The outer diameter a of the lock pin 4 is 1.5 mm, the inner diameter b of the recess 3 is 1.25 mm. The opening width c is formed to be 1.1 mm. Note that the lock pin 4 is solid and easy to mold. In this configuration, when the lock pin 4 is press-fitted into the concave portion 3 and the end of the magnetic tape T is clamped, the lock pin 4 is larger than the inner diameter of the concave portion 3 as apparent from FIG. Is deformed so as to protrude into the opening of the recess 3, and the protruding deformed portion fills the gap 5 between the opening of the recess 3, that is, the gap 5 is absorbed by the deformation of the lock pin 4. Will be done. For this reason, the step shape is not transferred to the magnetic tape T wound around the hub 2, and therefore does not cause dropout of the recording signal. Since the lock pin 4 is soft, it is deformed according to the shape of the concave portion 3 as shown in FIG. In addition, since the repulsive force is generated by being compressed in the concave portion 3, the magnetic tape T is more strongly sandwiched and a sufficient clamping force can be obtained. The inventors of the present invention conducted a comparative experiment of the tape clamping force by the material of the lock pin, and as a result, when the lock pin was formed of metal as in the prior art, the clamping force was 200.
In contrast to about 250 gf, when the lock pin was formed of resin as in this example, a clamping force of 600 to 700 gf was obtained. As is apparent from this, in the configuration of this embodiment, a sufficient tape clamping force is secured, so that even when a large load is applied to the tape clamp portion at the start and end of winding of the magnetic tape, the end portion of the magnetic tape is detached from the hub. There is no danger. A lock pin made of resin is less expensive than a lock pin made of a conventional metal (a metal lock pin has a cost of 0.3 per piece).
(Circles and resins are about 0.002 yen), which is advantageous in terms of cost. Although the embodiment of the present invention has been described above, the present invention is not limited to the microcassette as shown in the figure, but can be of course widely applied to audio compact cassettes, video cassettes and the like. . As described above, according to the present invention, the lock pin is formed of a flexible resin material, and the inner diameter of the recess in which the lock pin is fitted is formed smaller than the outer diameter of the lock pin. Thus, when the lock pin is fitted into the recess, the gap between the lock pin and the opening of the recess is absorbed by the deformation of the lock pin, so that the stepped shape is transferred to the tape wound around the hub. This can greatly contribute to the reduction of dropout, and the lock pin has good followability to the shape of the concave portion and rebound force is generated by being compressed in the concave portion. Since the lock pin made of resin is more inexpensive than the lock pin made of metal, the cost can be reduced. Further, in the present invention, since the lock pin is non-hollow, it can be easily formed at a low cost, and the non-hollow lock pin does not cause the tape to break.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main portion (tape clamp portion) of a hub showing an embodiment.
FIG. FIG. 2 is an explanatory diagram of a dimensional relationship between a lock pin and a recess in the embodiment. FIG. 3 is an explanatory diagram of a followability of a lock pin to a shape of a concave portion in the embodiment. FIG. 4 is a partially cutaway plan view of the microcassette. FIG. 5 is an explanatory view of a tape clamp for a hub. FIG. 6 shows a main part (tape clamp part) of a hub showing a conventional example.
FIG. FIG. 7 is an explanatory view of a shape of a concave portion in a conventional example. FIG. 8 is an explanatory diagram of a tape on which a step shape is transferred. [Description of Signs] T Magnetic tape 2 Hub 3 Recess 4 Lock pin

Claims (1)

(57) [Claims for Registering Utility Model] A pair of hubs around which a tape is wound are provided rotatably in a cassette housing, and a lock pin is fitted into a recess formed in the hub to form a terminal portion of the tape. In the tape cassette fixed to a hub, the lock pin absorbs a gap between the lock pin and an opening of the recess.
Polyamide resins If having deformable flexibility in so that
A tape cassette formed of a non-hollow shape with a polyurethane resin and having an inner diameter of the recess smaller than an outer diameter of the lock pin.