Fluid reaction surfaces (i.e. – impellers) – With heating – cooling or thermal insulation means
Reexamination Certificate
2001-11-19
2002-11-26
Verdier, Christopher (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
With heating, cooling or thermal insulation means
C416S143000, C244S13400A
Reexamination Certificate
active
06485261
ABSTRACT:
The invention relates to a rotary-wing aircraft rotor, whose blades are automatically foldable and equipped with electrical equipment, such as de-icing or anti-icing equipment, or even positioning lights or lamp(s) at the blade ends, or an electrical actuator to control a mobile member such as a blade flap, or any other electrical equipment requiring the routing of electrical energy to the blades from an electrical collector placed at the center of the hub of the rotor. This routing of electrical energy is provided by an electrical connection installation, essentially comprising an electrical harness comprising, for each blade, at least one electrical connecting cable, tied to a member for linking the corresponding blade to the hub of the rotor, and provided at its ends with connectors to ensure an electrical connection between the collector and the blade.
More precisely, the invention relates to a rotary-wing aircraft rotor, in particular a helicopter main rotor, of the type known in particular by EP-0 754 623 and FR 2 781 198 and comprising:
a hub, designed to be driven in rotation about an axis of the hub which is the axis of rotation of the rotor,
at least two blades, each of which is connected to the hub by a link member that is substantially radial with respect to the axis of rotation, each blade being firmly connected by its root to a folding mount, mounted in a pivoting manner at a radially outer end of the said link member, about an axis for folding the said blade between two positions, one of which is a flight position, in which the said mount is attached to the said link member in such a way that the said blade is substantially aligned in the projection of the said link member, and the other of which is a position folded along one side of the rotary-wing aircraft, in which the said mount and blade are pivoted about the said folding axis on one side of the said link member, and
an electrical connection installation comprising, for each blade, at least one electrical connecting cable connecting a first connector, carried by the hub and electrically connected on the latter, to a second connector on the blade and connected to at least one electrical device of the said blade.
On a rotor according to EP 0 754 623, the connecting cable, for each automatically foldable blade, comprises (see
FIGS. 7 and 13
) a first section, radially towards the outside, arranged like an overhead hook and extending from this blade to the corresponding link member, and connecting the second connector on this blade to a rotating part, with which this first section is integral in rotation, of a rotating connector coaxial with the folding spindle about an extension of this spindle, and whose fixed part is connected, mechanically and electrically, to a first end, in a radially outer position, of a second section of connecting cable, held substantially radially on this link member. This overhead hook of the connecting cable has a rounded cross section, possibly an armoured structure, and is connected to the second connector, which is itself connected to the electrical equipment, for example de-icing or anti-icing equipment of this blade, and when an actuator housed in the corresponding link member commands the pivoting of the mount with the blade about the folding spindle, this first section of cable rotates with the rotating part of the rotating connector about this same spindle, at the same time as the blade, which makes any intervention on the second connector useless.
However, during the foldings of the blade, the pivoting of the blade with the mount with respect to the corresponding link member can introduce tensions that can cause damage in the overhead hook and on the rotating part of the rotating connector and also on the second connector, and such a rotating connector is furthermore a relatively complex, costly and fragile component.
In fact, it is not recommended to give this overhead hook a length sufficient to allow the complete folding of the blade whilst guaranteeing the absence of tensions, because an overhead hook of such length would have large forces applied to it and would be subjected to ample flutter movements, favouring its catching on or an unwanted collision with adjacent components, such as blade root pendular anti-vibration devices, aerodynamic dome, sleeve or drag dampers, on a rotor in rotation, on which the corresponding blade carries out angular deflections in pitch, flapping and drag.
FR 2 781 198 proposes improvements to rotors with automatically foldable blades and an electrical de-icing installation according to EP 0 754 623, in particular for avoiding the use of rotating connectors and reducing the stresses and/or displacements of the connecting cable in its overhead hook section connecting the link member to the second connector on the blade, when the rotor is rotating and during the operations of folding and unfolding the blades.
For this purpose, according to FR 2 781 198 (see FIGS.
3
and
4
), an elongated part of this overhead hook, of substantially flattened rectangular cross section, whose biggest dimension is oriented substantially parallel with the axis of rotation of the rotor, is held in a member, mounted in a fixed manner or pivoting about the folding spindle, in the substantially axial projection of this folding spindle, and arranged as a fork in which the said elongated part of flattened cross section is engaged and held by at least one elastic tab. This retaining fork prevents the displacements of the overhead hook on either side of the folding spindle, during a blade's folding or unfolding, which prevents torsions harmful to this section of connecting cable, and is much more simple, economical and reliable than a rotating connector.
But the flattened rectangular cross section of this overhead hook section of cable above the link between the blade root and the link member favours a longitudinal slipping of the section of cable in the fork during the folding of the blade, and in particular generates a large aerodynamic drag, which causes a disturbing slipstream phenomenon. Furthermore, considering the angular movements, in particular of flapping and pitch combined, of this section of cable and of its mechanical link with the link member, when that latter and the blade are carrying out these angular movements, it has proved necessary to form recesses in the periphery of a profiled dome covering the rotor head, and this amplifies the said slipstream phenomenon.
The basic problem for the invention is to overcome these disadvantages whilst avoiding the use of rotating connectors, and avoiding the formation of a disturbing slipstream, caused by recesses in the profiled dome surmounting the rotor head and by a section of connecting cable with a flat profile oriented substantially parallel with the axis of the rotor.
For this purpose, the rotary-wing aircraft rotor according to the invention, of the type described above, is characterized in that the connecting cable comprises a first flexible section, of essentially cylindrical shape with a rounded cross section, preferably substantially circular, connecting the said second connector to a second section, held on the corresponding link member, of the said connecting cable, whose first section comprises a held part which, in all the positions of the blade about the folding spindle, is maintained fixed on a cable support tied to the said folding spindle, such that the said held part is maintained above the said mount and the said radially outer end of the said link member, in an off-centered position with respect to the said folding spindle and substantially on the folding side of the said blade, in order that the folding of the blade by pivoting about the said folding spindle causes the first section of cable to curve and to move naturally in order to accommodate itself to the said folding without extension of the said first section of cable.
The rounded shape of the cross section of the first section of cable sets up only a limited aerodynamic drag and allows, at the level of the connection with th
Mazet Stëphane
Mondet Jean
Eurocopter
Henderson & Sturm LLP
Verdier Christopher
LandOfFree
Rotary-wing aircraft rotors with automatically folding... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotary-wing aircraft rotors with automatically folding..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotary-wing aircraft rotors with automatically folding... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2981217