Method and apparatus for molding magnetic tape cassette

Claim 1

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.

Claim 2

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.

Claim 6

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.

Claim 7

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.

Claim 13

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.

Claim 14

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.

Claim 15

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.

Claim 16

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.

Claim 19

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.

Claim 20

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.