Plastic and nonmetallic article shaping or treating: processes – Pore forming in situ – Composite article making
Reexamination Certificate
2001-08-10
2003-09-23
Kuhns, Allan R. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Pore forming in situ
Composite article making
C264S045100
Reexamination Certificate
active
06623675
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
The present application claims priorities under 35 U.S.C. §119 to Japanese Patent Applications No. 2000-245038, filed Aug. 11, 2000 and Japanese Patent Application No. 2000-337810, filed Nov. 6, 2000, entitled “MANUFACTURING METHOD OF CUSHION MEMBER”. The contents of this application are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a manufacturing method of a cushion member which is used in a seat such as a sofa or the like within a vehicle, an airplane a ship or a room.
2. Description of the Background
Conventionally, a seat portion in a seat of a motor vehicle or the like is constructed such that a cushion member used in an inner portion thereof has a two-layer structure including a soft layer and a hard layer, so that the comfort of a user sitting on the seat is improved thereby.
As a method of manufacturing the cushion member having the two-layer structure mentioned above, for example, there is a method disclosed in Japanese Examined Patent Publication No. 6-11496 (a prior art
1
). In accordance with this method, in a molding die for forming the cushion member, there is provided a side partition between a center cavity for forming a first center portion in the seat portion of the seat and a side cavity for forming side portions positioned in both right and left sides. Further, in the center cavity, there is provided a front and rear partition for partitioning between a front portion and a rear portion.
Then, a soft raw material is injected to the front portion mentioned above, thereafter a hard raw material is injected to the other portions, whereby a soft layer is formed below the front portion, that is, in an obverse side in a front portion of the seat portion, and a hard layer is formed above the front portion, that is, in a reverse side in the front portion of the seat portion and side portions and the rear portion of the seat portion, so that the cushion member having the two-layer structure is formed.
However, the conventional manufacturing method of the cushion member mentioned above has the following problem.
That is, in the manufacturing method in accordance with the prior art
1
, a flow amount of the hard raw material later injected is not restricted at all at a time of molding by injecting the soft raw material and the hard raw material to the molding die. Accordingly, it is hard to keep a thickness of the soft layer and the hard layer to a predetermined thickness, so that a dispersion is necessarily generated locally or between production lots.
As the other conventional embodiments, for example, there are structures described in Japanese Unexamined Patent Publication No. 10-225943 (a prior art
2
) and Japanese Unexamined Patent Publication No. 2-140107 (a prior art
3
).
In the prior art
2
mentioned above, an injection hole for injecting a molding material and a closing lid mounted via a hinge portion for closing the injection hole after injecting the molding material are provided in a boundary member. At a time of forming the cushion member, the boundary member is arranged in a molding die for the cushion member, one molding material is injected from the injection hole, and another molding material is injected to an upper portion of the boundary member. Then, one molding material injected from the injection hole rotates the hinge portion by a foaming force thereof, whereby the closing lid closes the injection hole. Accordingly, the cushion member having the two-layer structure gripping the boundary member therebetween is formed.
In the prior art
3
mentioned above, a molding die for the cushion member has a middle frame between an upper die and a lower die, and the boundary member is arranged in the middle frame. Then, one molding material is injected to the lower die. Thereafter the middle frame is closed, next another molding material is injected in an upper portion of the middle frame, thereafter the upper die is closed and a foaming process is executed. Accordingly, the cushion member having the two-layer structure gripping the boundary member therebetween is formed.
However, in the conventional manufacturing method of the cushion member mentioned above, there is the following problem.
That is, in the prior art
2
mentioned above, as mentioned above, it is necessary that the closing lid having the injection hole and the hinge portion are provided in the boundary member, and in the prior art
3
, it is necessary that the middle frame is provided in the molding die in the manner mentioned above. In other words, in the prior arts mentioned above, the special structure is required in the boundary member or the molding die at a time of injecting.
In order to improve the above problems, in the prior art
2
mentioned above, there is another forming method in which a flexible partition member is used in the boundary member mentioned above and an injection port for the molding material is provided in the flexible partition member. However, in this forming method, it is impossible to enlarge the injection port enough and it is not easy to inject the molding material.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a manufacturing method of a cushion member for executing an expansion molding by using an upper die and a lower die, in which in the lower die, a first cavity for forming a first center portion having an obverse layer portion positioned in an obverse side of the cushion member and a reverse layer portion positioned in a reverse side of the cushion member, and a second cavity for forming a second center portion arranged at the rear of the first center portion are formed, and a front and rear partition is provided between the first cavity and the second cavity. The upper die has a bottom portion forming surface for forming a bottom portion of the cushion member. At a time of executing the expansion molding, a first raw material having a foaming property is injected to the first cavity and a second raw material having a foaming property and forming a foamed product having a different physical property from that of a foamed product formed of the first raw material at a time when the foaming process is completed is injected to the second cavity. Thereafter, the lower die and the upper die are closed so as to form a flow port between the bottom portion forming surface in the upper die and an upper end of the front and rear partition, the second raw material flows within the first cavity while being limited in a flow amount by the flow port and flows forward so as to follow the flow of a flow front end portion of the first raw material while covering over the first raw material so as to restrict an upward foam flow of the first raw material. Finally, the first raw material forms an obverse layer portion below the first cavity, and forms a front edge portion in a forward end portion of the first cavity, and on the other hand, the second raw material forms the reverse layer portion above the first cavity, and forms the second center portion in the second cavity.
A remarkable aspect of the present invention is that the lower die and the upper die are closed so as to form a flow port between the bottom portion forming surface and an upper end of the front and rear partition in the upper die, and the second raw material flows within the first cavity while being limited in a flow amount by the flow port and flows forward so as to follow the flow of a flow front end portion of the first raw material while covering over the first raw material so as to restrict an upward foam flow of the first raw material.
Next, a description will be given of an operation and effect of the present invention.
In the present invention, the first raw material is injected in the first cavity so as to foam and flow within the first cavity. Further, the second raw material is injected in the second cavity so as to ride over the front and rear partition and also foam and flow in the first cavity.
Then, the lo
Kobayashi Tetsuya
Tanaka Masashi
Kuhns Allan R.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokai Kogyo Kabushiki Kaisha
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