JP2979248B2 - Tape cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape cartridge having a front cover for protecting a tape, and more particularly to a measure against a molding defect of the front cover.

[0002]

2. Description of the Related Art As a tape cartridge having a front lid of this type, for example, there is a tape cartridge as shown in FIG. Here, a VHS tape cartridge is shown, and reels 3 around which a tape 2 is wound are housed on the left and right inside a main body case 1 as shown in a state where a front lid is opened in FIG. 3 is fed out to the front side of the front wall 4 of the main body case 1 and wound up on the other reel 3. A front cover 5 is attached to the front side of the main body case 1 so as to be freely openable and closable around the shaft 6 over a position where the front cover 4 covers the lead-out portion 2a of the tape 2 and a position where the tape 2 is exposed. . The front lid 5 is a plastic molded product, and is connected to a flat front plate 7 covering the entire length of the front wall 4 of the main body case 1 in the left-right direction as shown in FIGS. Upper surface plate 9 which is formed to cover the upper surface side of front wall 4
And a left and right side plate 10 having a shaft 6 connected to the left and right end sides of the front plate 7 and pivotally attached to the left and right side surfaces of the main body case 1. The sectional shape of the front lid 5 is shown in FIGS.
As shown in FIG. 7, only the surface 7a in the area opposite to the lead-out portion 2a of the tape 2 on the rear surface of the front plate 7 is provided with a thinner portion, and the corresponding portion is replaced by other portions 7b on the rear surface of the front plate 7, the upper surface plate 9, and the side plate. 10 are formed to be thinner than the respective thicknesses. The relationship of the thicknesses is as follows: the thickness t ₁ of the upper surface plate 9> the thickness t ₀ of the surface 7 a in a region of the front surface plate 7 facing the lead-out portion 2 a of the tape 2. and has a thickness t _2> t ₀ of elsewhere 7b of the rear surface of the front plate 7. Normally, t ₁ = t ₂ = 2 mm, t ₀ = 1.4 to 1.7
mm. In this manner, by uniformly reducing the thickness of only the surface 7a in the region facing the lead-out portion 2a of the tape 2 on the rear surface of the front lid 5, the tape 2 faces the tape 2 of the front plate 7 of the front lid 5 so far. Compared to a case where the entire surface including the region is formed to have a uniform thickness and a complete planar shape, material saving and weight reduction can be achieved.

[0003]

However, there is a difference in wall thickness as seen from the whole like the front lid 5 of the above-mentioned prior art, and the surface 7a of the thinned wall portion has a uniform thickness. In this case, the flow of the resin becomes uneven at the thin surface 7a of the front plate 7 during the injection molding, and a weld line is easily generated on the surface of the front plate 7, which is defective not only in appearance but also in strength. In some cases, there is a disadvantage that color unevenness or the like due to entrainment of gas easily occurs. The present invention has been made in order to solve such a problem. By changing the thickness of a surface 7a in a region facing the lead-out portion 2a of the tape 2 on the rear surface of the front lid 5, a weld line, color unevenness, etc. It is an object of the present invention to provide a front lid molded product having a good appearance by reducing the defect phenomenon of the above.

[0004]

As shown in FIG. 1, a tape cartridge according to the present invention has a surface in a region facing a lead portion 2a of a tape 2 of a plastic front lid 5 provided in a main body case 1. The deviation is provided in the wall thickness of 7a.

[0005]

As described above, by continuously changing the thickness of the surface 7a of the front lid 5, it is possible to partially vary the flow resistance of the resin during molding. As a result, the resin flows preferentially to the thick portion where the flow resistance is small, so that the resin flow can be controlled by the difference in the thickness of the entire front lid 5 and the occurrence of weld lines and color unevenness is reduced. became.

[0006]

According to the present invention, the surface 7a of the area of the plastic front lid 5 facing the lead-out portion 2a of the tape 2 is made partly thinner than the other parts, so that the material can be saved and the weight can be reduced. By providing a thicker portion, a front lid molded product excellent in appearance without weld lines or color unevenness can be obtained.

[0007]

FIG. 1 is a sectional view of a front cover showing one embodiment of the present invention. Although this embodiment is directed to a VHS tape cartridge, it can be similarly applied to other tape cartridges having a front lid.

The basic structure of the tape cartridge and the structure of the front cover are the same as those of the above-described conventional one (FIG. 4). Only the cross-sectional shape different from 5 will be described.

The tape 2 on the rear surface of the front plate 7 of the front lid 5
The thickness of the surface 7a in the region opposed to the lead-out portion 2a is thinnest at the lower end A of the surface 7a, gradually increases from the location A toward the upper end B, and becomes thickest at the upper end B. For example, the lower end A has a thickness of 1.4 mm, and the upper end B has a thickness of 2 mm. By doing so, the front plate 7 during molding can be formed.
Of the resin flowed around preferentially from the upper end portion B side, and almost no weld line or uneven color was generated, and even if it was generated.

FIG. 2 is a sectional view of a front lid 5 showing another embodiment. In this case, on the surface 7a on the rear surface of the front plate 7,
The thickness is the thickest near the center C in the vertical direction of the surface 7a, and becomes thinner toward the upper end portion B and the lower end portion A from this location. For example, the thickness of the central portion C in the vertical direction is 2 mm. Also in this case, as in the case of the above embodiment, the occurrence of weld lines and color unevenness was reduced.

FIG. 3 is a cross-sectional view of a front lid 5 showing still another embodiment. In this case, the thickness of the surface 7a on the rear surface of the front plate 7 is increased from a position slightly above the central portion C in the vertical direction of the surface 7a toward the upper end portion B, and is thickest at the upper end portion B. For example, the thickness of the upper end portion B is 2 mm. Also in this case, as in the case of the above embodiment, the occurrence of weld lines and color unevenness was reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a front lid.

FIG. 2 is a sectional view of a front lid showing another embodiment.

FIG. 3 is a sectional view of a front lid showing still another embodiment.

FIG. 4 is a perspective view showing a conventional tape cartridge with a front cover opened.

FIG. 5 is a plan view of a conventional front lid.

FIG. 6 is a front view of a conventional front lid.

FIG. 7 is a rear view of a conventional front lid.

8 is a sectional view taken along line VIII-VIII in FIG.

FIG. 9 is a sectional view taken along line IX-IX in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body case 2 Tape 2a Tape lead-out part 5 Front lid

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 23/087 521 G11B 23/113 510

Claims (1)

(57) [Claims] 1. A main body case 1 is provided with a front cover 5 made of plastic, which is openable and closable, covering a leading portion 2a of a tape 2 led out to the front side thereof. A tape cartridge characterized in that a deviation is provided in the thickness of a surface 7a in a region facing the portion 2a.