Auxiliary jig

Details Auxiliary jig Auxiliary jig

2001-09-04

2004-03-16

Davis, Robert (Department: 1722)

Plastic and nonmetallic article shaping or treating: processes

Mechanical shaping or molding to form or reform shaped article

To produce composite, plural part or multilayered article

C264S313000, C425S111000, C425SDIG004, C249S163000, C249S187100

Reexamination Certificate

active

06706230

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to an auxiliary jig used for forming a structure made of a fiber-reinforced composite.
Stiffened panels made of a fiber-reinforced composite (prepreg) are light in weight and high in strength to have been widely used for automobiles, ships, aircrafts, etc. The stiffened panels generally comprise a skin strengthened by a plurality of stiffeners (stringers and frames), the skin and the stiffeners being integrally formed.
FIG. 1
is a partial perspective view showing an example of the stiffened panel. A stiffened panel
1
shown in
FIG. 1
comprises a skin
2
and a stiffener
3
integrally formed therewith. As shown in FIGS.
4
(
a
) and
4
(
b
), the stiffened panel may be produced by a method comprising the steps of: placing a skin member
2
and a preformed stiffener member
31
each made of a fiber-reinforced composite on a forming tool
4
; disposing a couple of jigs
5
a
and
5
b
on the preformed stiffener member
31
; and integrally forming the skin member
2
and the preformed stiffener member
31
by heating under a pressure using a pressure bag, etc.
The above-mentioned method is disadvantageous in that a resin contained in the fiber-reinforced composite often flows out from an interspace between the jigs
5
a
and
5
b
in the direction of arrow A shown in FIG.
4
(
b
) while heating under a pressure. If a large quantity of the resin flows out from the interspace, the resultant fiber-reinforced composite structure is poor in such a quality as strength, rigidity, etc. Thus, as shown in
FIG. 5
, the resin has been conventionally restrained from flowing out by sticking a temperature resistant tape
7
to the preformed stiffener member
31
and the jigs
5
a
and
5
b
disposed thereon. However, the process of sticking the temperature resistant tape is complicated and troublesome, thereby requiring much effort.
Further, in the above-mentioned method, the jigs
5
a
and
5
b
often fall down while heating under a pressure as shown in FIG.
6
. In this case, the resultant fiber-reinforced composite structure is poor in form accuracy with unevenness stiffener thickness. The fiber-reinforced composite structure can be formed with high form accuracy by using a large-scale jig together with the jigs
5
a
and
5
b
, however, this results in increased costs and poor workability.
OBJECT AND SUMMARY OF THE INVENTION
An object of the present invention is to provide an auxiliary jig used for forming a structure made of a fiber-reinforced composite with high form accuracy without reduction of strength and rigidity.
As a result of intensive research in view of the above object, the inventors have found that a structure made of a fiber-reinforced composite having desired strength and rigidity can be formed with high form accuracy by using a particular auxiliary jig together with a couple of jigs while forming. The present invention has been accomplished by the finding.
Thus, an auxiliary jig of the present invention is used with a couple of jigs for forming a structure made of a fiber-reinforced composite by heating under a pressure, the auxiliary jig being provided between the couple of jigs to prevent the jigs from falling down and to restrain a resin contained in the fiber-reinforced composite from flowing out from an interspace between the jigs.
The auxiliary jig of the present invention preferably comprises a rigid portion and an elastic portion. The rigid portion is preferably made of a stainless steel, aluminum, graphite or CFRP, and the elastic portion is particularly preferably made of a silicone rubber.
The auxiliary jig of the present invention is particularly preferably used for forming a stiffened panel. Thus, a stiffened panel having uniform, excellent qualities can be produced with high form accuracy by a method comprising the steps of: placing an skin member and a preformed stiffener member each made of a fiber-reinforced composite on a forming tool; disposing the couple of jigs on the preformed stiffener member; providing the auxiliary jig of the present invention between the jigs; and integrally forming the skin member and the preformed stiffener member by heating under a pressure.


REFERENCES:
patent: 6245275 (2001-06-01), Holsinger
patent: 6391246 (2002-05-01), Shiraishi et al.
patent: 6478922 (2002-11-01), Rosevear et al.
patent: 6508909 (2003-01-01), Cerezo Pancorbo et al.
patent: 6523246 (2003-02-01), Matsui et al.

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