Metal working – Method of mechanical manufacture – Impeller making
Reexamination Certificate
2003-03-26
2004-04-27
Omgba, Essama (Department: 3726)
Metal working
Method of mechanical manufacture
Impeller making
C029S889200, C029S889220, C029S890010
Reexamination Certificate
active
06725541
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a flow director, for example a thrust reverser cascade for a gas turbine engine, and in particular relates to a flow directing element, for example a thrust reverser cascade element for a turbofan gas turbine engine.
BACKGROUND OF THE INVENTION
A thrust reverser cascade element generally comprises at least two plates and a plurality of flow directing vanes. A plurality of vanes extend between each pair of plates.
It is known to manufacture thrust reverser cascade elements for turbofan gas turbine engines by casting the thrust reverser cascade elements from molten aluminium or molten magnesium. This method requires the use of a mould for each thrust reverser cascade element, and each thrust reverser cascade may comprise a number of different thrust reverser elements requiring different moulds. Thus the casting of thrust reverser cascade elements is expensive and time consuming in the requirement to make the different moulds and in heating the metal to melting point and subsequently casting the molten metal.
It is also known to manufacture thrust reverser cascade elements for turbofan gas turbine engines by moulding and curing the thrust reverser elements from composite structures, for example carbon fibre reinforced resins. This method also requires the use of a mould for each thrust reverser cascade element, and each thrust reverser cascade may comprise a number of different thrust reverser elements requiring different moulds. Thus the moulding and curing of thrust reverser cascade elements is expensive and time consuming in the requirement to make the different moulds and in heating the resins to cure the resin and consolidate the carbon fibre and resins to the appropriate density and shape. The thrust reverser cascade elements comprising composite structures do not have sufficient strength.
U.S. Pat. No. 4,030,299 discloses the manufacture of a thrust reverser cascade for gas turbine engines by securing together sheet metal vanes and sheet metal plates, for example aluminium or titanium. Each of the vanes is formed from a separate piece of sheet metal.
Published European patent application EP0219889A discloses the manufacture of a thrust reverser cascade for gas turbine engines by producing a metallic skeletal frame and moulding/curing a composite structure, for example carbon fibre reinforced nylon around the metallic skeletal frame.
SUMMARY OF THE INVENTION
Accordingly the present invention seeks to provide a novel flow directing element which reduces, preferably overcomes, the above mentioned problems.
Accordingly the present invention provides a flow directing element comprising a plurality of plates and a plurality of flow directing vanes, at least one vane extends between each pair of plates, the plurality of plates are formed from sheet material and a single integral piece of ductile sheet material forms the plurality of flow directing vanes, the single integral piece of ductile sheet material has a plurality of spaced apart apertures and a plurality of sheet material portions, each sheet material portion defines one of the plurality of flow directing vanes.
Preferably a plurality of vanes extend between each pair of plates.
Preferably the single integral piece of ductile sheet material has a plurality of longitudinally spaced apart apertures and a plurality of longitudinally spaced apart sheet material portions between the apertures and the ductile sheet material is bent at a plurality of longitudinally spaced positions such that each sheet material portion defines one of the plurality of flow directing vanes.
Preferably the single integral piece of ductile sheet material has a plurality of transversely spaced apart apertures, a plurality of transversely spaced apart sheet material portions, a plurality of longitudinally extending slots between the transversely spaced apart sheet material portions and a plurality of transversely extending webs longitudinally between the slots, the webs extending over at least one of the plurality of plates and the ductile sheet material is bent at a plurality of longitudinally spaced positions such that each sheet material portion defines one of the plurality of flow directing vanes.
Preferably the plates have a plurality of slots on one of their edges and the webs locate in the slots in the edges of the plates.
Preferably the plates have a plurality of longitudinally spaced apart apertures extending therethrough, each longitudinally extending slot in the ductile sheet material has projections on its edges which locate in a corresponding one of the apertures in one of the plates.
Preferably each longitudinally extending edge of the single integral piece of ductile sheet material has at least one twist lock, each twist lock locates in an aperture in one of the plurality of plates.
Preferably each longitudinally extending edge of the single integral piece of ductile sheet material has a plurality of longitudinally spaced twist locks, each twist lock locates in a corresponding aperture in one of a plurality of longitudinally spaced apertures in one of the plurality of plates.
Preferably a pair of end plates extend transversely to the plurality of plates and the single integral piece of ductile sheet material.
Preferably each transversely extending end of the single integral piece of ductile sheet material has at least one twist lock, each twist lock locates in an aperture in one of the end plates.
Preferably each transversely extending end of the single integral piece of ductile sheet material has a plurality of twist locks, each twist lock locates in a corresponding one of a plurality of apertures in one of the end plates.
Preferably each transversely extending end of each plate has at least one twist lock, each twist lock locates in an aperture in one of the end plates.
Preferably each transversely extending end of each plate has a plurality of twist locks, each twist lock locates in a corresponding one of a plurality of apertures in one of the end plates.
Preferably the single integral piece of ductile sheet material comprises a metal, more preferably the single integral piece of ductile sheet material comprises aluminium, titanium, mild steel or stainless steel.
Preferably the plates comprise a metal, more preferably the plates comprise aluminium, titanium, mild steel or stainless steel.
Preferably the end plates comprise a metal, more preferably the end plates comprise aluminium, titanium, mild steel or stainless steel.
Preferably the flow directing element comprises a thrust reverser cascade element. Preferably a gas turbine engine thrust reverser comprises one or more thrust reverser cascade elements.
The present invention also provides a method of manufacturing a flow directing element comprising the steps of:
(a) forming a plurality of plates, the plurality of plates are formed from sheet material,
(b) forming a single integral piece of ductile sheet material such as to form a plurality of flow directing vanes, forming a plurality of spaced apart apertures and a plurality of sheet material portions,
(c) arranging the single integral piece of ductile sheet material such that at least one vane extends between each pair of plates and each sheet material portion defines one of the plurality of flow directing vanes.
Preferably step (c) comprises arranging the single integral piece of ductile sheet material such that a plurality of vanes extend between each pair of plates.
Preferably step (b) comprises forming a plurality of longitudinally spaced apart apertures in the single integral piece of ductile sheet material and forming a plurality of longitudinally spaced apart sheet material portions between the apertures and bending the ductile sheet material at a plurality of longitudinally spaced positions such that each sheet material portion defines one of the plurality of flow directing vanes.
Preferably step (b) comprises forming a plurality of transversely spaced apart apertures in the single integral piece of ductile sheet material, forming a plurality of transversely spaced
Bishop Jeffrey C
Holme Michael J
Manelli Denison & Selter PLLC
Omgba Essama
Rolls-Royce plc
Taltavull W. Warren
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