Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
2002-12-20
2003-07-29
Koehler, Robert R. (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C228S181000, C228S219000, C228S221000, C228S254000, C228S262100, C228S262510, C428S646000, C428S647000, C428S650000, C428S652000, C428S655000, C428S656000, C428S658000, C428S674000, C428S675000, C428S680000, C428S116000, C428S182000, C428S184000, C428S186000, C428S926000, C428S935000
Reexamination Certificate
active
06599645
ABSTRACT:
FIELD OF THE INVENTION
The invention is concerned with a composite rigid metal panel comprising at least two parallel metal plates and/or sheets secured to a corrugated aluminium stiffener sheet arranged between the parallel metal plates and/or sheets, and further to a composite panel comprising two parallel plates and/or sheets secured to aluminium stiffener sheet having a honeycomb structure. The invention further relates to a method of manufacturing thereof.
DESCRIPTION OF THE RELATED ART
Composite metal panels having an interior honeycomb structure are usually manufactured by means of adhesion bonding, such as for example disclosed in U.S. Pat. No. 6,054,200. Composite metal panels having an interior of corrugated sheet such that the peaks and troughs thereof are bonded to the parallel metal plates are usually manufactured by means of adhesion bonding or by welding techniques, such as by laser welding techniques as disclosed in for example international application WO-00/26020. The stiffness of the composite metal panel is to a large extent the resultant of the design of the corrugated sheet or of the honeycomb structure.
Composite metal panels are being used in load bearing structures such as for the floor or cargo decks of a ship, tooling board, floor or wall panels of an aircraft or a land-transportation vehicle, e.g. a truck or a car, architectural panels, energy absorption purposes, or for the construction of interior or exterior walls of a building. There is a demand for an all metal composite panel construction, preferably a light-weight metal panel, and which is easy to manufacture.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a composite metal panel which is easy and reliable to manufacture.
It is a further object of the present invention to provide a composite metal panel which can be manufactured by means of brazing.
It is a further object of the present invention to provide a composite metal panel in which the parallel metal plates and/or sheets may be dissimilar to each other and/or dissimilar to the aluminium stiffener sheet.
It is a further object of the present invention to provide a composite metal panel having aluminium stiffener sheet which may be employed both as corrugated sheet and as a honeycomb-like structure.
According to the invention in one aspect there is provided a rigid composite metal panel including at least two metal parallel plates and/or sheets secured to the peaks and troughs of a corrugated aluminium stiffener sheet arranged between the parallel plates and/or sheets, characterized in that the corrugated aluminium stiffener sheet is an aluminium brazing sheet product made from an aluminium brazing sheet product including a core sheet (
1
) made of an aluminium alloy having on at least one surface of the core sheet clad, and preferably on both sides, an aluminium alloy clad layer (
2
), the aluminium alloy clad layer being made of an aluminium alloy comprising silicon in an amount in the range of 2 to 18% by weight, preferably 5 to 14%, and a layer (
3
) including nickel on the outer surface of said aluminium alloy clad layer.
According to the invention in another aspect there is provided a rigid metal composite panel including at least two parallel metal plates and/or sheets secured to aluminium stiffener sheet having a honeycomb structure arranged between the parallel plates and/or sheets, characterized in that the corrugated aluminium stiffener sheet is made from an aluminium brazing sheet product including a core sheet (
1
) made of an aluminium alloy having on at least one surface of the core sheet clad, and preferably on both sides, an aluminium alloy clad layer (
2
), the aluminium alloy clad layer being made of an aluminium alloy comprising silicon in an amount in the range of 2 to 18% by weight, preferably 5 to 14%, and a layer (
3
) including nickel on the outer surface of said aluminium alloy clad layer.
By the invention it is possible to provide a light-weight all-metal composite metal panel which is very rigid, and may be used for various load-bearing constructions. By the invention it is possible to provide a composite metal panel which may be bonded or secured together in a simple and reliable manner by means of a brazing operation, in particular under controlled atmosphere brazing (“CAB”) conditions in the absence of a brazing flux material, such as the commonly known NOCOLOK (trade name) brazing flux material. It has been found that the aluminium brazing sheet product used may be formed into corrugated sheet of various shape by means of, e.g., roll-forming, and may also be formed into a honeycomb-like shape. Suitable corrugated sheets have for example the shape of flat peaks and troughs, a dovetail shape or curved peaks and troughs. A suitable honeycomb-like structure may be formed for example from two or more corrugate stiffener sheets each with flat peaks and troughs and whereby the peak of one sheet is brazed to the trough of the other corrugated sheet. The rigid honeycomb-like structure will be formed in the same brazing operation as in which the honeycomb-like structure is bonded by means of brazing to the parallel metal plates or sheets. Furthermore, the use of the present brazing sheet product for the manufacture of composite metal panels allows for a honeycomb core having various number of various density honeycomb portions, due to variations in densities or other cell sizes.
In an embodiment of the composite metal panel according to the invention the corrugated aluminium stiffener sheet is in the form of turbulator sheet, and thereby allowing to design and to manufacture particular rigid metal composite panels. Turbulator sheet is an expression known in the art for manufacturing heat exchangers.
In an embodiment of the composite metal panel according to the invention the corrugated aluminium stiffener sheet is a formed sheet having a plurality of cup-like cavities, which cup-like cavities are aligned in essentially parallel rows and whereby in alternating parallel rows the openings of the cup-like cavities are facing opposed directions. The tip surfaces of the cup-like cavities form the peaks or alternatively the troughs of the corrugated stiffener sheet, and the tip surfaces are joined by brazing to the parallel metal plates or sheets. The tip surfaces may be flattened in order to increase the contact surface area with the parallel metal plates or sheets, and thereby increasing the strength of the joint after brazing. The cup-like cavities may have several forms, such as circular, cylindrical, spherical or cone-shaped. Corrugated stiffener sheet of this type allows for the design and manufacture of composite metal panels with improved stiffness in multiple directions. Corrugated stiffener sheets having such a structure are known in the art per se and are in particular applied as heat-shields in cars and trucks, in which known application the sheet material is made from one aluminium alloy only and is not made of brazing sheet, and in particular not of brazing sheet comprising a core sheet having multiple metal layers of different composition.
In an embodiment of the aluminium brazing sheet product said layer comprising nickel further comprises bismuth in a range of at most 5% by weight.
In accordance with the invention it has been found surprisingly that the nickel layer does not need to comprise any lead as a mandatory alloying addition in order to achieve good brazeability. Surprisingly it has been found that equal or even better results can be obtained if bismuth is added to the nickel layer, such that the nickel layer can be kept essentially lead-free and simultaneously also in the plating bath used for the deposition of this Ni—Bi layer. This is of particular relevance since the use of lead for manufacturing brazed components and used in various market areas is undesirable and it is envisaged that in the near future there might possibly even be a ban on lead comprising products or products manufactured via one or more intermediate processing steps comprising lead or lead-bas
Corus Aluminium Walzprodukte GmbH
Koehler Robert R.
Stevens Davis Miller & Mosher LLP
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