Method and apparatus for molding magnetic tape cassette
AssigneeFuji Photo Film Co., Ltd.
InventorKiyoo Morita
Life of this patent
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Abstract
A method and apparatus for molding casing halves of a magnetic tape cassette in which one or more-windows in the casing half are firmly retained by remaining portions thereof regardless of the solubility of the two plastic materials employed or other molding conditions. The window is formed with a projecting edge portion which extends well into the plastic of the remaining portions of the casing half. In one embodiment, the window is molded first and then the remaining portions are molded around the edge portions of the window. In another embodiment, the other portions are molded first using slidable cores to define the window portions, and then the windows are molded.
Claims18
A method for molding a casing half of a magnetic tape cassette having first and second portions and having an inner surface, comprising the steps of:
- providing a first mold having a cavity configuration which is the same as that of said first portion, wherein said first mold is formed by a first die and a moveable die positioned in a first position and wherein said first mold has at least one protrusion or recess in an edge region thereof;
- filling said first mold with a first plastic to mold said first portion;
- moving said moveable die to a second position so that said moveable die and a second die form a second mold having a configuration the same as that of said casing half, wherein moving said moveable die to said second position places said first portion in said second mold;
- filling said second mold with a second plastic in regions thereof not occupied by said first portion to mold said second portion;
- and
- maintaining the entire inner surface of said first portion completely flat.
A method for molding a casing half of a magnetic tape cassette, said casing half having an inner surface, comprising the steps of:
- providing a fixed die and a rotatably movable die, wherein said rotatably movable die is rotatably movable between a first position, in which a first cavity is defined between said fixed and rotatably movable dies, and a second position, in which a second cavity is defined between said fixed and rotatably movable dies, wherein said first cavity has a configuration of a window portion of said casing half and said second cavity has a configuration of said casing half, and wherein said first cavity includes a recess along an edge portion thereof;
- placing said rotatably movable die in said first position;
- filling said first cavity with a first plastic to mold said window portion of said casing half wherein said window portion has a projecting edge portion corresponding to said recess;
- rotatably moving said rotatably movable die with said window portion thereon to said second position such that said window portion is placed within said second cavity;
- filling said second cavity with a second plastic to mold a remaining portion of said casing half;
- and
- maintaining the entire inner surface of said window portion completely flat.
A method for molding a casing half of a magnetic tape cassette, said casing half having an inner surface, comprising the steps of:
- providing a mold having a cavity defined by first and second dies, wherein said first die has a movable core disposed therein and wherein said moveable core has an urging means to urge a plurality of projections to extend beyond edge portions of said moveable core;
- positioning said movable core in said cavity so that said moveable core and said plurality of projections substantially form a shape of a window portion of said casing half;
- filling said cavity with a first plastic to mold portions of said casing half other than said window portion;
- withdrawing said movable core into said first die so that said plurality of projections withdraw into said movable core;
- filling portions of said cavity vacated by said movable core and said plurality of projections with a second plastic to mold said window portion;
- and
- maintaining the entire inner surface of said window portion completely flat.
An apparatus for molding a casing half of a magnetic tape cassette, said casing half having an inner surface, comprising:
- a fixed die;
- a rotatably movable die, wherein said rotatably movable die is rotatably movable between a first position, in which a first cavity is defined between said fixed and rotatably movable dies, and a second position, in which a second cavity is defined between said fixed and rotatably movable dies, wherein said first cavity has a configuration of a window portion of said casing half and said second cavity has a configuration of said casing half, and wherein said first cavity has a recess along an edge portion thereof;
- a moveable core slidably disposed in said rotatably movable die, wherein said movable core has a surface corresponding to an inner surface of said window portion and said recess is defined between said fixed and rotatably movable dies around said movable core;
- and
- maintaining means for maintaining the entire inner surface of said window portion completely flat.
An apparatus for molding a casing half of a magnetic tape cassette, said casing half having an inner surface, comprising:
- a first die and a second die defining a molding cavity therebetween having a configuration of said casing half;
- a movable core slidably mounted in said second die and extendable into said cavity, wherein said movable core comprises a plurality of projecting tip portions extending laterally in said cavity perpendicular to a sliding direction of said movable core, wherein said projecting tip portions are slidably mounted in said movable core, and wherein a portion of said moveable core within said molding cavity and said projecting tip portions substantially have a configuration of a window portion of said casing half;
- and
- maintaining means for maintaining the entire inner surface of said window portion completely flat.
Dependencies are inferred from the claim text.