JPS6138544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic tape cartridge having a structure in which a viewing window for viewing the winding amount of magnetic tape is provided in the main body case, and a tape winding amount display scale is provided on a transparent plate of the viewing window. Improvements have been made in terms of how to insert the parts with ease of assembly.

To explain the details based on the drawings, Fig. 1 shows an example of a so-called Phillips type magnetic tape cartridge, the main body case 1 of which is made of polystyrene resin, and the tape wound between two reels inside. This is a standard specification in which a body 1b which houses a magnetic tape 2 and is divided into upper and lower halves and a lid 1a are screwed together at the corners. At the center of the upper and lower surfaces of the main body case 1, wide-opening rectangular viewing windows 4 are provided between the left and right drive shaft insertion holes 3, 3, respectively.

As shown in FIG. 2, the structure of the viewing window 4 is such that a window 5 is transparently provided at the concentric position of the body 1b and the lid 1a, and a stepped surface 6 is formed at the inner periphery of the opening of the window 5. Then, a flat transparent plate 7 made of stretched polystyrene resin is fitted onto this step surface 6 flush with the inner surfaces of the body 1b and the lid 1a from the inside and ultrasonically welded. Thereafter, preferably on the outer surface of the transparent plate 7, a scale 8 is provided to indicate the amount of winding of the magnetic tape 2 inside the main body case 1.

Now, this invention has a peephole 4 having such a structure.
To obtain a magnetic tape cartridge having a magnetic tape cartridge, first, the transparent plate 7 is molded as follows. First, as shown in Fig. 2A, a polystyrene resin material is stretched in the longitudinal direction and the width direction to form an endless sheet S having a constant thickness and a constant width. After this is taken out in a suitably rolled state, it is cut with a cutter 9 at equal intervals to a predetermined width corresponding to the window 5, thereby obtaining a rectangular flat transparent plate 7. Second, the thus obtained transparent plates 7 are grasped one by one using an appropriate fitting means 10 and fitted from the inside to the stepped surface 6 of each viewing window 4, and then the peripheral edge of the transparent plate 7 made of the same material is fitted. The contact surface with the stepped surface 6 is ultrasonically welded. Then, a tape winding amount display scale 8 is stamped in a concave or convex manner on the outer surface of the transparent plate 7 using a hot stamp means 11 from the outside of the main body case 1, thereby forming a viewing window 4.

In addition, instead of the above method, the transparent plate 7 can be placed at the window 5.
It may be attached with adhesive. In addition, a stepped surface is formed on the outer periphery of the opening of the window 5, and a transparent plate 7 is formed on this stepped surface.
It is also possible to fit and adhere from the outside of the main body case 1. Further, the display scale 8 may be placed on the inner surface of the transparent plate 7, or the means for placing it may be printed and colored as appropriate. These design changes are also included in the present invention.

In short, according to the present invention, after the transparent plate 7 is attached to the window 5 of the main body case 1, the tape winding amount display scale 8 is engraved on the transparent plate 7 by means such as a hot stamp. Therefore, on a series of assembly lines for magnetic tape cartridges, the display scale 8 can be inserted easily and accurately without bending while the main body case 1 is reliably positioned, further improving the assembly work efficiency. can. Furthermore, 60 minutes・
Even when assembling different types of magnetic tape cartridges for 90 minutes and 120 minutes, there are advantages such as the ability to freely change the display scale 8 after attaching the transparent plate 7. have

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic tape cartridge according to the present invention, and FIG. 1... Main body case, 3... Drive shaft insertion hole, 4... Peephole, 5... Window, 6... Step surface, 7... Transparent plate, 8...
Tape winding amount display scale, S...endless sheet made of stretched polystyrene resin.

Claims (1)

[Scope of Claims] 1. A magnetic tape cartridge characterized in that a transparent plate 7 is attached to a window 5 provided in the main body case 1, and a tape winding amount display scale 8 is subsequently engraved on the transparent plate 7. . 2. The magnetic tape cartridge according to claim 1, wherein the window is provided at the center of the upper and lower surfaces of the main body case 1. 3. A transparent plate 7 formed by cutting an endless sheet S made of stretched polystyrene resin into a predetermined width is fitted from the inside onto the stepped surface 6 at the inner periphery of the opening of the window 5 provided in the main case 1 made of polystyrene resin. A magnetic tape cartridge according to claim 1 or 2, which is attached together by high frequency welding. 4. Claim 1, in which the tape winding amount display scale 8 is engraved on the transparent plate 7 by hot stamping.
The magnetic tape cartridge according to item 1 or 2 or 3.