JPH0233347Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a slippery sheet inserted between the inner surface of a cassette tape case and a tape roll.

(Prior Art) Conventionally, as this type of slippery sheet, there are known sheets that are curved into an arch shape during molding and sheets that have a plurality of large dome-shaped protrusions formed at equal intervals.

(Problems to be solved by the invention) The former of the above-mentioned conventional slippery sheets has variations in the degree of curvature and becomes fatigued after long-term use, becoming almost like a flat plate, causing the tape roll to become elastic. This has the disadvantage that the magnetic tape is wound unevenly and the winding torque is uneven because the gripping function is reduced and the frictional force increases. Due to the contact, the frictional force is smaller than the former, but it still has the disadvantage that it is not sufficient.

The object of the present invention is to provide a slippery sheet for cassette tapes that does not have the above-mentioned disadvantages.

(Means for Solving the Problems) The present invention provides a slippery sheet inserted between the inner surface of a case and a tape roll, in which a large number of bosses are arranged in a direction from the inside to the outer edge of the slippery sheet. The bosses are arranged in a plurality of rows, the intervals between the bosses are gradually widened from the inner side toward the outer edge, and the bosses are curved in the opposite direction to the protruding direction of the bosses.

(Embodiment) FIGS. 1 and 2 show an embodiment of the present invention.
In the figure, reference numeral 1 denotes a circular, square, etc. boss press-formed on the surface of the slippery sheet S, and the boss 1 extends from the central axis L parallel to the long side of the slippery sheet S. The bosses 1 are arranged in a plurality of rows in the direction, and the intervals between the bosses 1 gradually become wider from the central axis L toward the long sides. Due to this arrangement configuration of boss 1,
The slippery sheet S curves symmetrically about the central axis in a direction opposite to the direction in which the boss 1 projects.

As shown in FIGS. 3 and 4, this curved slippery sheet S is attached to the upper case 3, the lower case 4, and the tape roll 2 with the protruding side of the boss 1 facing the tape roll 2. It is inserted in a curved manner in between.

Thus, in the assembled state of the cassette tape, the boss 1 of the slippery sheet S comes into elastic pressure contact with the side surface of the tape winding body 2, and prevents the tape from being undone by a small frictional force.

5 to 7 show other embodiments of the present invention.

In the figure, reference numeral 5 denotes a through hole through which the drive shaft of the tape is inserted, and the bosses 1 are arranged in multiple rows radially toward the long and short sides of the sheet S with the through hole 5 as the center. The intervals between the bosses 1 are gradually widened from the through hole 5 toward the long side and the short side. Due to this arrangement of the bosses 1, the slippery sheet S curves symmetrically in approximately three directions around the through hole 5 in a direction opposite to the direction in which the bosses 1 protrude.

Thus, when the cassette tape is assembled,
The bosses 1 of the slippery sheet S come into pressure contact with the side surfaces of the tape roll 2 more uniformly and elastically than those shown in FIGS. 3 and 4.

(Effect of the invention) According to the invention, a large number of bosses are arranged in a plurality of rows from the inside to the outside edge of the sheet, and the intervals between the bosses gradually become wider from the inside to the outside edge. As a result, the sheet is curved in the opposite direction to the protruding direction of the boss, so there is less variation in the degree of curvature compared to conventional sheets, and even after long-term use, it will remain close to a flat plate due to fatigue. Therefore, the frictional force is small over a long period of time, and its variation is small, and there are effects such as less uneven rotation and less irregular winding of the magnetic tape.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG.
The figures are a cross-sectional view taken along the line - - of Fig. 3, Fig. 5 is a plan view of another embodiment of the present invention, and Fig. 6 is a - line sectional view of Fig. 5.
7 shows a cross-sectional view taken along the line -- of FIG. 5. 1...Boss, 2...Tape winding body, 3...Upper case, 4...Lower case, 5...Through hole.

Claims (1)

[Scope of utility model registration request] In the slippery sheet inserted between the inner surface of the case and the tape roll, a large number of bosses are arranged in multiple rows from the inside to the outer edge of the slippery sheet, and from the inside to the outside. A slippery sheet for a cassette tape, characterized in that the intervals between the bosses are gradually widened toward the edge, and the bosses are curved in a direction opposite to the direction in which the bosses protrude.