Abstract: An injection molding method and device, wherein, in order to minimize dimension errors of molded products, molten resin is injected from a nozzle (23) retaining therein pre-pressurized molten resin such as plastic into the cavity (3) via an annular gate (24).

Abstract: Disc storage case (1) for storing a plurality of discs (20) comprises a case body (2) having a cylindrical protuberance (4), the outer diameter 4a of which is encompassed by an elastic member (5), and a protrusion (10) that freely enters and exits the inner diameter (4a) of the protuberance (4).

Abstract: A valve pin (4) for controlling an injection amount of molten resin is inserted into a cavity (13), and then the molten resin is injected by way of a gate (10) along the surface of the valve pin (4) into the cavity (13) to be dropped therein, and tip ends of this dropping molten resin merges at a bottom (13a) of the cavity (13) to form a hollow portion (S) between the valve pin (4) and the dropped molten resin. Then, air is blown into the hollow portion (S) from the tip end of the valve pin (4), inflates the hollow portion (S), brings it into contact with the inner surface of the cavity (13), and cools and solidifies this molten resin, so as to attain a hollow molded product (40).

Abstract: A valve pin (24b) of a valve for injecting molten resin is inserted into a cavity (31) formed in a mold (22), then the molten resin is injected and filled by way of a gate (30) into a space formed between the valve pin (24b) and the cavity (31). Then the molten resin is cooled and solidified so as to provide a molded product of synthetic resin.

Abstract: The present invention is directed to a magnetic recording tape cassette having a bottom case and a top case, both of the cases being assembled and fastened together by means of screws threadingly engaged in holes provided in each of the bosses disposed on the front corners of the bottom case. The respective bosses on the bottom case are provided with at least one rib extending therefrom with a predetermined width and length, thereby reinforcing the bosses.

Abstract: The present invention is directed to a hub for use in a tape casette for winding a recording tape around the periphery of the cylindrical surface. The hub includes a drive shaft inserting hole at the center portion thereof; a notch for fastening the end of the recording tape in association with a tape securing member on the peripheral cylindrical surface; a first and a second surface opposed to each other, each surface having an inner annular surface and an outer annular surface; and a resin injection gate surrounded by a concave recess located in the outer annular surface of the first surface. In addition, the present invention includes a recess formed on the outer annular surface of the second surface at a position opposite to the resin injection gate, the bottom face of the recess being substantially parallel to the outer annular surface of the second surface.

Abstract: A magnetic recording tape cartridge of a Phillips type which comprises a slip sheet for assuring uniformity of the winding of a tape pack on a hub, said slip sheet being provided with at least three embossed convex ribs of special material radially extended with respect to a pair of drive shaft inserting holes, each of said ribs having closed ends said ribs being disposed on the slip sheet in the positions and the directions specially defined so as to prevent fluctuation of the hub and the tape pack during winding the magnetic recording tape in said cartridge.

Abstract: A magnetic recording tape cartridge which includes partition walls protrusively provided, behind a central opening for insertion of a magnetic recording and reproducing head on the front side of upper and lower cases, said partition walls being extended at their both ends to positions behind the two openings for insertion of a pinch roller and an erasing head on both sides of the central opening, each of said partitions walls being so disposed as to couple at its front surface with the back of U-shaped guide walls provided protrusively on the case opposite to at least one of said openings, so as to ensure suppressing of the deformation of the case caused by warping and allow smooth running of the magnetic recording tape accommodated in the tape cartridge.