JPS639882Y2 - - Google Patents

Description

[Detailed description of the invention] This invention aims to make the upper and lower divided cases that make up the case body of a magnetic tape cartridge as symmetrical as possible so that plastic molding can be performed with high precision. This is the main focus.

In the Philips type magnetic tape cartridge as shown in FIG. Plastic hubs 4, 4 are rotatably installed above the drive shaft insertion holes 3, 3 provided on the left and right sides of the central part of the drive shaft, and both ends of the magnetic tape 5 are locked and wound around both hubs 4, 4. The tape 5 is fed out from one supply hub 4, passes through an erasing head insertion hole 6 opened in the front of the case body 1, a recording/playback magnetic head insertion hole 7, and then a pinch roller insertion hole 8 to be taken up on the other side. It is designed to be wound around the side hub 4. At both ends of the tape running path formed across the aforementioned insertion openings 6, 7, and 8, that is, at the inner depths of the erasing head insertion hole 6 and the pinch roller insertion hole 8, a tape is positioned behind the tape running path. A pair of left and right capstan holes 9, 9 are transparently provided, and capstan frames 10, 10 are respectively erected on the rear side of each hole 9, 9. Prevents dust from entering the case body.

However, when we examine in detail the upper and lower cases 1a and 1b that constitute the conventional case body 1, we find that the lower case 1b is located on the tape feeding side of the tape running path (left side in the figure), as shown in Fig. 6. A capstan frame 10 is formed to protrude higher than the upper and lower case mating surfaces behind the capstan hole 9 located at , and tape guide portions a higher than the vertical width of the magnetic tape 5 are formed on the left and right front ends of the capstan frame 10, The capstan frame is omitted and a depressed portion b is formed at the rear of the capstan hole 9 located on the tape winding side (right side in the figure). on the other hand,
Although the upper case 1a is omitted from illustration, the left and right sides of the lower case 1b are reversed, and a capstan frame 10 having a tape guide portion a is erected behind the capstan hole 9 on the right side, and It has a shape with a depression part b at the rear. and,
When the upper and lower cases 1a and 1b are placed one on top of the other, the capstan frame 10 of one case engages with the depressed portion b of the other case, making them symmetrical.

The problem here is that although each of the cases 1a and 1b basically has a substantially symmetrical shape, the capstan frame 10 and the depressed portion b are largely asymmetrically present on the left and right sides of the front. As a result, the volume of plastic material on the left and right sides was different during molding, making it difficult to expect uniform cooling shrinkage after molding, and the case was likely to warp due to imbalance in shrinkage stress. This "warp" is the upper and lower case 1
Needless to say, when a and 1b are screwed together, this is undesirable as it creates a gap between the mating surfaces of the two. In addition, the upper and lower cases 1a, 1
It was also undeniable that the strength of the side where the depressed portion b was present in b was insufficient.

This invention was proposed in order to eliminate such conventional drawbacks, and a specific example thereof will be explained below with reference to the drawings.

The basic structure of the magnetic tape cartridge is as described above, and improvements are shown in FIGS.

FIG. 2 shows the lower case 1b. In this case, capstan frames 10, 10 are symmetrically installed at the same height behind the left and right capstan holes 9, respectively.

Its height is set to be the same as the height of the peripheral edge of the lower case 1b, that is, the lid mating surface of the upper and lower cases 1a and 1b. On the left and right front ends of the capstan frame 10 located on the tape feeding side, plate-shaped tape guide pieces 11 running in the front-rear direction are erected higher than the upper end surface of the frame 10, and are located on the tape winding side. A notch 12 is provided at the front end of the capstan frame 10.
12 was formed. In addition, capstan frames 10, 10 similar to those of the lower case 1b are installed symmetrically behind the left and right capstan holes 9, 9 in the upper case 1a, respectively, and their upper end surfaces are set to be the same as the case mating surfaces. ing. However, in the upper case 1a, the tape guide pieces 11, 11 and the notch 1
2 and 12 are formed in a horizontally opposite positional relationship with respect to the lower case 1b. In this case, when the upper and lower cases 1a and 1b are overlapped, the left and right capstan frames 10 and 10 of the upper and lower cases 1a and 1b are flush with the case mating surfaces, respectively, as shown in FIGS. 3 to 5. When they come into contact, each tape guide piece 11 engages in the notch 12 of the mating case, so that the tape guide pieces 11 guide the tape at both ends and left and right sides of the tape running path.

According to the present invention as described above, the front left and right capstan frames 10, 10 are symmetrical in each of the upper and lower cases 1a, 1b. Each case 1a/1
Tape guide piece 11 and notch 1 on the front left and right sides of b.
Although there remains some volume difference due to No. 2, the difference as a whole is considerably smaller than that of the conventional one. Therefore, each case 1a and 1b can be made so that there is as little difference in the volume of plastic material on the left and right sides as possible, and the problems of "warping" and local lack of strength that occur during plastic molding can be solved. Ivy.

In addition to the above-mentioned notch 12, the notch 12 can be formed by completely removing the front end portion of the capstan frame 10.
The tape guide piece 11 of the mating case may be positioned, and various forms can be considered.

In addition, in the present invention, capstan frames 10 and 10 are provided on the left and right sides of the upper and lower cases 1a and 1b, respectively.
The upper end surface of the case is set at almost the same height as the case mating surface. Further, in each of the upper and lower cases 1a and 1b, a tape guide piece 11 is provided at the front end of one of the left and right capstan frames 10, respectively, to stand higher than the frame 10, and when the lids are aligned, a tape guide piece 11 is installed at the front end of the other capstan frame 10. Tape guide piece 11 of the other side case
Assuming that the tape guide piece 11.1 is located
1 are equally divided and arranged in each of the upper and lower cases 1a and 1b. Therefore, the difference in the volume of the plastic material between the upper and lower cases 1a and 1b can be eliminated as much as possible, so even when the upper and lower cases 1a and 1b are assembled and molded into plastic at the same time, uniform cooling can be achieved. It has the advantage of being able to shrink and can be molded into plastic with high precision.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view of the magnetic tape cartridge to which the present invention is applied, Fig. 2 is a perspective view of the lower case, Fig. 3 is a sectional view taken along line A-A in Fig. 1, and Fig. 4 is 1, and FIG. 5 is a sectional view taken along line CC in FIG. 1. FIG. 6 is a perspective view of the lower case in the conventional example. 1...Case body, 1a...Upper case, 1b...
...Lower case, 3...Drive shaft insertion hole, 4...Hub,
5...Magnetic tape, 6...Erasing head insertion hole, 7
... Magnetic head insertion hole for recording and playback, 8 ... Pinch roller insertion hole, 9 ... Capstan hole, 10 ...
Capstan frame, 11...Tape guide piece, 12
...notch.

Claims (1)

[Scope of utility model registration request] A capstan frame 1 is located behind the capstan holes 9 and 9 provided on the left and right pairs of the upper and lower cases 1a and 1b.
0 and 10 are set up almost symmetrically, and the upper end surfaces of these left and right capstan frames 10 and 10 are set at approximately the same height as the lid mating surfaces of the upper and lower cases 1a and 1b. A plate-shaped tape guide piece 11 running in the front-rear direction is installed at the front end of one of the left and right capstan frames 10 to stand higher than the upper end surface of the frame 10, and when the lids are aligned, the tape guide piece 11 is attached to the front end of the other capstan frame 10. A magnetic tape cartridge characterized in that a tape guide piece 11 of a side case is positioned.