Plastic article or earthenware shaping or treating: apparatus – Means to create a vacuum or apply fluid pressure within a...
Reexamination Certificate
1998-10-15
2001-04-17
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
Means to create a vacuum or apply fluid pressure within a...
C156S382000, C264S571000
Reexamination Certificate
active
06217310
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a tooling apparatus for composite fabrication and, more particularly, to a tooling which encapsulates the composite material to be fabricated and holds it in place during fabricating processing steps such as off-gassing and consolidation.
BACKGROUND ART
In the prior art, it is known to consolidate composite materials comprising layers of fibers and a matrix together by first off-gassing the composite material followed by consolidation. These types of composite materials are shown in
FIG. 1
wherein the composite material is designated by the reference numeral
10
. The composite material
10
comprises a series of layered fibers
1
surrounded by a matrix
3
.
Typically, the fibers
1
and matrix
3
are held together with an adhesive
5
in what is typically called a green form, see
FIG. 2
, reference numeral
20
. The adhesives
5
are usually organic materials which have been dissolved in a solvent. The green form
20
is placed in a tool and is subjected to a vacuum to remove any moisture in the green form
20
as well as the organic material of the adhesive
5
. The off-gas processing volatizes the water and adhesives by heating the green form to the appropriate volatizing temperature.
One of the problems with prior art tooling in this regard is the inability to allow the volatized water and adhesives to be removed while holding the composite material in place so that it can be subsequently consolidated. In prior art apparatus, the composite material is subjected to shifting which disrupts the orientation and spacing of the reinforcing materials therein, for example, the fibers
1
in the composite
10
of FIG.
1
. With this disruption, the consolidated composite material has less than desirable product characteristics.
As such, a need has developed to provide an improved tooling apparatus which not only allows the volatized water and adhesives to be removed but also keeps the green form in place during off-gassing and consolidation.
Responsive to this need, the present invention provides a tooling apparatus which overcomes the deficiencies in the prior art apparatus discussed above. That is, according to the invention, the inventive tooling apparatus includes features which not only permit off-gassing to occur but also hold the composite material in place so that the composite can be subjected to both off-gassing and consolidation.
SUMMARY OF THE INVENTION
Accordingly, it is a first object of the present invention to provide a tooling apparatus for the fabrication of layered or composite materials.
A further object of the present invention is to provide a tooling apparatus which encapsulates the composite material to be off-gassed and consolidated by using means for applying pressure to the composite material during off-gassing and consolidation.
A still further object of the present invention is to provide a tooling apparatus which facilitates evacuating a tooling apparatus cavity for off-gassing.
Yet another object of the present invention is to provide an apparatus which utilizes atmospheric pressure as a loading means in combination with evacuation to hold or secure a composite material to be off-gassed and subsequently consolidated.
Other objects and advantages of the present invention will become apparent as a description thereof proceeds.
In satisfaction of the foregoing objects and advantages, the present invention provides, in its broadest sense, a vacuum tooling apparatus which utilizes a flexible bag, the flexible bag made of a metallic material having a low interstitial gas content. The bag forms a cavity which is sized to receive an organic material-containing composite material which is to be subjected to off-gassing and consolidation. The bag has a thickness and flexibility which permits atmospheric pressure to retain the composite material in place when the cavity is subjected to a vacuum. The tooling apparatus also includes at least one evacuation port in the bag to permit evacuation of the cavity. The bag is sealed along its periphery except for the one or more evacuation ports.
In one embodiment, the evacuation port comprises tubing which is attached to the flexible bag.
In a second embodiment, the evacuation port comprises an opening in the bag, the opening including means for connecting the opening to a vacuum source. With this embodiment, a quick connector is also provided which facilitates connecting the interior of the bag to the vacuum source.
In a third embodiment, the cavity receiving the composite material for evacuation is formed by a frame, plungers, an encapsulating bag and one or more evacuation ports. The frame surrounds the composite material to be off-gassed and consolidated. The plungers provide a loading force/restraint on the top and bottom of the composite material. The encapsulating bag in combination with the frame forms the cavity enclosing both the composite material and plungers for evacuation. Evacuation ports may be made part of the frame to evacuate the cavity. The frame also may include one or more spacers, generally in the configuration of a picture frame which provide thickness adjustment for the tooling apparatus to accommodate the plunger thicknesses as well as the green and final thicknesses of the composite material being fabricated.
In a fourth embodiment of the invention, the tooling apparatus described for the third embodiment is used in combination with another encapsulating bag. In this embodiment, one of the plungers is contained in an encapsulation bag which is then connected to the vacuum source via evacuation ports. The cavity which is evacuated in the third embodiment is pressurized in the fourth embodiment, the pressure in this cavity combining with the plunger enclosed in the evacuated encapsulating bag to retain the composite material in place during off-gassing and consolidation.
In a fifth embodiment of the invention, mechanical loading means are provided in conjunction with one or both of the plungers to adjust the loading on the composite material during evacuation. These mechanical loading means are used in the apparatus according to the third embodiment.
In a sixth embodiment, the tooling apparatus includes a base plate which can receive one or more composite materials. The composite materials are covered by an encapsulating sheet to form a cavity which can be evacuated similarly to that described for the first and second embodiments above. The encapsulating sheets are secured to the base plate via a sealing means. The base plate with the encapsulating sheets enclosing the composite materials are then mounted in a frame assembly similar to that disclosed in the fourth embodiment. The frame assembly is then pressurized to provide the necessary pressure on the evacuated cavities containing the composite material for off-gassing and consolidation.
REFERENCES:
patent: 2636539 (1953-04-01), Pajak
patent: 3072225 (1963-01-01), Cremer et al.
patent: 3307999 (1967-03-01), Boicey
patent: 4062917 (1977-12-01), Hill et al.
patent: 4073674 (1978-02-01), Hortel
patent: 4174241 (1979-11-01), Rockar et al.
patent: 4314013 (1982-02-01), Chang
patent: 4492607 (1985-01-01), Halcomb
patent: 4504341 (1985-03-01), Radzwill et al.
patent: 4517147 (1985-05-01), Taylor et al.
patent: 4681718 (1987-07-01), Oldham
patent: 4886442 (1989-12-01), McCowin et al.
patent: 4975311 (1990-12-01), Lindgren
patent: 5089328 (1992-02-01), Doerer et al.
patent: 5123985 (1992-06-01), Evans et al.
patent: 5225015 (1993-07-01), Allaire et al.
patent: 5260137 (1993-11-01), Rosenthal et al.
patent: 5266249 (1993-11-01), Grimes, III et al.
patent: 5298102 (1994-03-01), Pohl
patent: 5316462 (1994-05-01), Seemann
patent: 5368807 (1994-11-01), Lindsay
patent: 5370760 (1994-12-01), Mori et al.
patent: 5425494 (1995-06-01), Rosenthal et al.
patent: 5427304 (1995-06-01), Woods et al.
patent: 399578 (1933-10-01), None
patent: 1460449 (1977-01-01), None
patent: 2261627 (1993-05-01), None
Hanusiak Lisa B.
Hanusiak William M.
Parnell Jeffrey M.
Rowe Charles R.
Spear Steven R.
Atlantic Research Corporation
Davis Robert
Nixon & Vanderhye P.C.
LandOfFree
Tooling apparatus for composite fabrication does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tooling apparatus for composite fabrication, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tooling apparatus for composite fabrication will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2511435