Note: Descriptions are shown in the official language in which they were submitted.
CA 02531793 2006-O1-06
WO 2005/005077 PCT/NL2004/000493
Method for the production of a semi-finished product for a win -~.sha~ed
element
The invention relates to a method for the production of a semi-finished
product fox a
wing-shaped element and of the wing-shaped element itself. Such wing-shaped
elements
are found in many different embodiments. A so-called vane, which is fixed to a
flap of an
aircraft wing, is 'mentioned as an example.
Various production methods for such wing-shaped elements are known. Extrusion
of
the element is mentioned first. In such a case the element does not have to be
made up of
separate components, which is quick and relatively inexpensive. The
disadvantage,
however, is that the dimensional tolerance is poor. This arises, in
particular, in the case of
relatively small thicknesses. According to a further known method the element
is produced
from sheet material. After pre-forming the sheet material, this is stretched
on a stretcher
leveller for making sections that has a bottom block and top block. A mandrel
is
incorporated in the pre-formed sheet material. The whole is clamped at the
longitudinal
ends and then stretched. The disadvantage of this known method is that the
surface
obtained has irregularities.
The aim of the invention is to provide a method for the production of a semi-
finished
product for a wing-shaped element that does not have these disadvantages. Said
aim is
achieved by means of a method for the production of a semi-finished product
for a wing-
shaped element having, in cross-section, a front edge, a rear edge and an
arched bottom
wall and an arched top wall that extend some distance apart between the front
edge and the
rear edge, comprising the following steps:
- providing a metal sheet,
- be~~di~xg the sheet with the fora~~~tas~n of t-~o pa~ael~ a.~ yell a~ a
curFie~l regioxi vrhich
2~ the panels adjoin,
- pro~iiding a. former, the e~~terbor of vJhich h~,s the shape of the
inter~~al surface of the
frnislle l section
- placing the former in the bent sheet with the front edge of the former
positioned in
the curved region,
- providing an edge press provided with a pressure member and a rubber cushion
located opposite,
- fixing the former to the pressure member,
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- forcing the pressure member towards the rubber cushion with the bent sheet
enclosed between them and deforming 'said sheet between the former and the
rubber
cushion,
- removing the former with shaped sheet from the edge press,
- placing these in a rubber press provided with a bottom block having a cavity
which
has a shape that at least approximately corresponds to the external shape of
one of the walls
of the shaped sheet,
- pressing the shaped sheet with former between the bottom block and a rubber
mat,
- removing the semi-finished product from the rubber press.
With the method according to the invention the semi-finished product is shaped
by
exerting pressing forces thereon via rubber elements. In combination with the
former acting
as a mandrel that has the correct contour, an extremely accurate shape is
obtained by this
means which has a surface that has the smoothness desired for aircraft for
aerodynamic
reasons.
The two panels are preferably arched after, or before, or at the same time as
bending
the sheet. The arching can be oriented in the same direction in order to
obtain a relatively
strong cured element.1-Iowever, the archings can also be oriented away from
one another.
fending and optionally arching the panels can be effected by means of roller
forming
or by means of rolling. The rear edge of the element can be made as a section
that is fixed
to the top wall and the bottom wall. Fuuthermore, the wing-shaped element can
be
subjected to a heat treatment, for example stress-free annealing or solution
annealing.
The invention also relates to a wing-shaped element produced in accordance
with the
method according to the method described above, which element, for example,
can be
a~~~~~1~ ~~ ~. ~~~r_~~~e
I~.eference is made t~ the wing-shaped element that is disclosed in ~.T~-~ 4
X31 2~Oo
This element is prcaducesl from ~, relatively flat section that comprises two
panels that forim
a, whole and i~a ~%hich the arching of the ultiamate walls has been pre-
produced by s locs.115~
greater material thickness. The element is obtained from this by simply
folding the panels
onto one another, after which the element is ready. The element concerned here
is in the
form of a blade for turbines.
The invention will be explained in more detail below with reference to an
illustrative
embodiment shown in the figures.
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WO 2005/005077 PCT/NL2004/000493
Fig. 1 shows a curved and arched sheet that serves as starting material for
the method
according to the invention.
Fig. 2 shows the element in an edge press.
Fig. 3 shows the result after performing a treatment in the edge press.
Fig. 4 shows a perspective view of the rubber press block of a rubber press,
with the
mandrel.
Fig. 5 shows the product obtained after rubber pressing.
Fig. 6 shows the finished wing-shaped element.
When carrying out the method according to the invention the starting material
used is
the bent sheet 1 shown in Fig. 1, which has been bent with the formation of a
bent front
edge 2, a concave arched panel 3 and a convex arched panel 4. This bent sheet
1 is placed
in the edge press 5 shown in Fig. 2, which has a base 6 with rubber cushion 7
as well as a
pressing member 8 that can be moved up and down and to which the former 10 is
fixed by
means of the supports 9. This former 10 or mandrel 10 is also shown in a
perspective view
in Fig. 4. It has the shape of the internal surface of the finished wing-
shaped element, that
is to say with a front edge, rear edge and arched top surface and bottom
surface. The former
can have a prismatic shape but also a twisted shape.
When pressing the bent sheet 1 in the edge press, the front edge of the
fornler 10 is
pushed into the curved region 2 of the sheet 1. ~y this means this curved
region is curved
~0 more severely around the front edge of the former 10, under the influence
of the even
inward pressure by the rubber cushion 7. As a consequence of this, the arched
panels 3 and
4 come closer together, as shown in Fig. 3.
The sheet 1 further shaped in this way is then placed in a rubber press, the
rubber
la~-e~ blo~l~ 11 of e~~hach can be se Ja~a i~a F'ig. ~., tl~e i~~teriar sh~lae
of ~,~lvich corre~laon~-1~ t~
'~ J the front edge and an arched surface of the ~~,ring-shaped element.
T'r~gether with ma~ld~rel
109 the sheet 1g v~hach now has the sl~~.pe as ~ho~vn in Fig. 3, as placed in
this ~-ubbex press
block 11. The rubber rnat 1~ is then placed on top of the whole of ths, after
which the
sheet 1 with the mandrel 10 therein is compressed between the rubber press
block 11 aa~d
the rubber mat 12 by a press (not shown).
30 After rubber pressing, the semi-finished product 13 shown in Fig. 5 is
obtained,
which has a curved front edge 2, a convex arched top surface 2 and a concave
arched
bottom surface 3. Finally, the section indicated in its entirety by 14 is
fixed to the rear, free
ends of the walls 2, 3. For this purpose the section has a body 15 with sides
1 ~, 17 tapering
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down with respect to one another that are oriented in accordance with the run
of the top
wall 2 and the bottom wall 3. The section 14 is fixed to the semi-finished
product 13 by
means of rivets 18 driven through the top wall 2, the body 15 and the bottom
wall 3, after
which the wing-shaped element 15 is ready. As an alternative, the walls 2, 3
can also be
fixed directly to one another, such as by bonding, riveting and the like.
