Stock material or miscellaneous articles – Structurally defined web or sheet – Including variation in thickness
Patent
1995-10-20
1998-05-05
Loney, Donald
Stock material or miscellaneous articles
Structurally defined web or sheet
Including variation in thickness
428131, 428178, 428118, B32B 328
Patent
active
057471428
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a former used for manufacture of articles of composite reinforced plastics material.
BACKGROUND ART
Articles of fibre reinforced material, including hollow stiffening ribs, and/or core materials, may be made by "laying up", that is to say by placing a layer of woven or non-woven reinforcing fibres upon a mould surface and then impregnating that layer with the hard setting plastic material while in a liquid or pasty state and subsequently allowing, or causing the plastic to set.
Composite structures frequently rely on ribs, or core materials to increase their strength and rigidity. These are generally applied to one side whilst the composite is being "layed up" over the desired mould surface. Many items are used to form the rib sections, that is, paper, cardboard tubes, timber, plastic, foam materials etc. A foraminous sheet with spaced apart arched sections with holes between is another method.
Core materials are frequently used and consist of plastic foam, plywood, timber, end grain balsa or similar.
DISCLOSURE OF THE INVENTION
The present invention seeks to provide an improvement over the prior art by use of a sheet of material as the former, creating the core of a sandwich structure of mouldings or panels.
According to a first aspect, the present invention provides a former for use in a core sandwich of composite reinforced plastics material, the former comprising a plurality of parallel rib sections each joined to adjacent rib sections by a flexible bridge portion to define openings in the former between each bridge portion and the rib sections, each rib section being divided into a plurality of sub-sections by a depression or groove formed in an upper surface of the rib section, the base of the groove forming a hinge or web section between each adjacent sub-section and having slits or openings in the side walls of the rib section extending between the base of the rib section and the base of each groove.
According to a second aspect, the present invention provides a former for use in a core sandwich of composite reinforced plastics material, the former comprising a plurality of parallel rib sections each joined to adjacent rib sections by a flexible bridge portion to define openings in the former between each bridge portion and the rib sections, each rib section being divided into a plurality of sub-sections by a depression or groove formed in an upper surface of the rib section and extending to the base of the rib section, the base of the groove forming a hinge or web section between each adjacent sub-section.
According to a third aspect, the present invention provides a former for use in a core sandwich of composite reinforced plastics material, the former comprising a sheet having an array of upstanding formations formed therein and each joined to an adjacent formation by a flexible bridge portion to define openings in the sheet of the former between each bridge portion and the upstanding formations.
For preference, the former is integrally formed, preferably from a sheet of material.
Preferably, the bridge portion is shaped to provide a venting channel between adjacent rib sections or formations. For preference, the bridge portion is arcuate or angular in cross section to provide the venting channel.
For preference, the walls of the rib sub-sections or upstanding formations are provided with stiffening formations. These formations may be in the form of grooves or ridges. Similar stiffening formations may be provided on the upper surfaces of the rib sections or formations if desired. Preferably, the ends of the former are shaped to enable joining in a complementary fashion with the ends of further like formers.
To allow small dimensional alterations and flexibility, the former sheet is preferably segmented and joined together in such a manner that each segment is vented to the other and cut out between. This simplifies the method by which compound curving of the sheet may be achieved on a curvaceous surface.
The venting between sections is an o
REFERENCES:
patent: 3899805 (1975-08-01), McMillan
patent: 4027058 (1977-05-01), Wooten
patent: 4906508 (1990-03-01), Blankenburg et al.
patent: 5364686 (1994-11-01), Disselbeck et al.
patent: 5451377 (1995-09-01), Asher
Form-Rite Plastics Development Pty., Ltd.
Klein David I.
Loney Donald
Rosenberg Morton J.
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