US 4,776,782 AGranted

Rotational plastic compression molding apparatus

AssigneeJapan Crown Cork Co., Ltd.

InventorsKashiwa Murayama, Osamu Ishii, Yoshiaki Mochino

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Abstract

A rotational plastic compression molding apparatus including a plurality of circumferentially spaced female molds and a plurality of circumferentially spaced male molds cooperating respectively with the plurality of the female molds. The female molds and the male molds are rotated in synchronism and thus moved round successively through a material loading zone, a compression molding zone and an article discharge zone. In the material loading zone and the article discharge zone, each said female mold and each corresponding mold are maintained in a spaced-apart inoperative relation, and in the compression molding zone, they are maintained in an approaching operative relation to define a mold space therebetween. In the material loading zone, a heat-melted plastic material is loaded in the female molds, and in the article discharge zone, the compression-molded plastic article is discharged from between each said female mold and each corresponding male mold.

Claims24

Dependent claims

A rotational plastic compression molding apparatus for compression molding a container closure having a top panel wall and a cylindrical skirt wall extending downwardly from the peripheral edge of the top panel wall, said apparatus comprising

a plurality of circumferentially spaced female molds,
each said female mold defining the outside surface of the top panel wall of the closure and at least a greater portion of the outside surface of the skirt wall,
a plurality of circumferentially spaced male molds cooperating respectively with the plurality of the female molds,
each said male mold defining the inside surface of the top panel wall of the closure and the inside surface of the skirt wall,
rotationally driving means for rotating the female molds and the male molds in synchronism, thereby moving them round successively through a material loading zone, a compression molding zone and a closure discharge zone,
mold relation control means for maintaining each said female mold and each corresponding male mold in a spaced-apart inoperative relation in the material loading zone and the closure discharge zone, and in an approaching operative relation to define a mold space therebetween in the compression molding zone,
material loading means for loading a heat-melted plastic material into the female molds in the material loading zone,
closure discharge means for discharging the compression-molded closure from between each said female mold and each corresponding male mold in the closure discharge zone, and
each said male mold including a sliding piece disposed for free movement from its normal position in a direction away from the corresponding female mold, the forward end surface of the sliding piece defining the central part of the inside surface of the top panel wall of the closure, and spring means for elastically biasing the sliding piece of said normal position, whereby when the pressure acting on the plastic material in the mold space becomes excessive, the sliding piece is moved from the normal position in the direction away from the corresponding female mold against the elastic biasing action of the spring member.

6 more elements

a plurality of circumferentially spaced female molds,
each said female mold defining the outside surface of the top panel wall of the closure and at least a greater portion of the outside surface of the skirt wall,
a plurality of circumferentially spaced male molds cooperating respectively with the plurality of the female molds,
each said male mold defining the inside surface of the top panel wall of the closure and the inside surface of the skirt wall,
rotationally driving means for rotating the female molds and the male molds in synchronism, thereby moving them round successively through a material loading zone, a compression molding zone and a closure discharge zone,
mold relation control means for maintaining each said female mold and each corresponding male mold in a spaced-apart inoperative relation in the material loading zone and the closure discharge zone, and in an approaching operative relation to define a mold space therebetween in the compression molding zone,
material loading means for loading a heat-melted plastic material into the female molds in the material loading zone,
closure discharge means for discharging the compression-molded closure from between each said female mold and each corresponding male mold in the closure discharge zone, and
each said male mold including a sliding piece disposed for free movement from its normal position in a direction away from the corresponding female mold, the forward end surface of the sliding piece defining the central part of the inside surface of the top panel wall of the closure, and means for forcibly holding the sliding piece at said normal position releasably, whereby when the pressure acting on the plastic material in the mold space becomes excessive, the forcible holding action of said means is released to move the sliding piece from said normal position in the direction away from the corresponding female mold.

6 more elements

a plurality of circumferentially spaced female molds,
each said female mold defining the outside surface of the top panel wall of the closure and at least a greater portion of the outside surface of the skirt wall,
a plurality of circumferentially spaced male molds cooperating respectively with the plurality of the female molds,
each said male mold defining the inside surface of the top panel wall of the closure and the inside surface of the skirt wall,
rotationally driving means for rotating the female molds and the male molds in synchronism, thereby moving them round successively through a material loading zone, a compression molding zone and a closure discharge zone,
mold relation control means for maintaining each said female mold and each corresponding male mold in a spaced-apart inoperative relation in the material loading zone and the closure discharge zone, and in an approaching operative relation to define a mold space therebetween in the compression molding zone,
material loading means for loading a heat-melted plastic material into the female molds in the material loading zone,
closure discharge means for discharging the compression-molded closure from between each said female mold and each corresponding male mold in the closure discharge zone, and
each said female mold including a sliding piece disposed for free movement from its normal position in a direction away from the corresponding male mold, the forward end surface of the sliding piece defining the central part of the outside surface of the top panel wall of the closure, and spring means for elastically biasing the sliding piece to said normal position, whereby when the pressure acting on the plastic material in a mold space becomes excessive, the sliding piece is moved from said normal position in the direction away from the corresponding male mold against the elastic biasing action of the spring means.

6 more elements

a plurality of circumferentially spaced female molds,
each said female mold defining the outside surface of the top panel wall of the closure and at least a greater portion of the outside surface of the skirt wall,
a plurality of circumferentially spaced male molds cooperating respectively with the plurality of the female molds,
each said male mold defining the inside surface of the top panel wall of the closure and the inside surface of the skirt wall,
rotationally driving means for rotating the female molds and the male molds in synchronism, thereby moving them round successively through a material loading zone, a compression molding zone and a closure discharge zone,
mold relation control means for maintaining each said female mold and each corresponding male mold in a spaced-apart inoperative relation in the material loading zone and the closure discharge zone, and in an approaching operative relation to define a mold space therebetween in the compression molding zone,
material loading means for loading a heat-melted plastic material into the female molds in the material loading zone,
closure discharge means for discharging the compression-molded closure from between each said female mold and each corresponding male mold in the closure discharge zone, and
each said female mold including a sliding piece disposed for free movement from its normal position in a direction away from the corresponding male mold, the forward end surface of the sliding piece defining the central part of the outside surface of the top panel wall of the closure, and means for forcibly holding the sliding piece at said normal position releasably, whereby when the pressure acting on the plastic material in the mold space becomes excessive, the forcibly holding action of said forcibly holding means is released, and the sliding piece is moved from said normal position in the direction away from the corresponding male mold.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/481,421Filed 1 Apr 1983
Priority: JP 57-560216 Apr 1982
Granted: 11 Oct 1988
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

B29C 43/34
Component parts, details or accessories; Auxiliary operations: feeding the material to the mould or the compression means
B29C 43/08
Continuously movable in one direction, e.g. mounted on chains, belts: with circular movement , e.g. mounted on rolls, turntables
B29C 43/42
Moulds for making articles of definite length, i.e. discrete articles: for undercut articles
B29C 43/50
Component parts, details or accessories; Auxiliary operations: removing moulded articles