(19)
(11)EP 2 971 728 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
02.09.2020 Bulletin 2020/36

(21)Application number: 14807682.1

(22)Date of filing:  13.03.2014
(51)International Patent Classification (IPC): 
F02K 1/60(2006.01)
F02K 1/06(2006.01)
F02K 1/11(2006.01)
F02K 1/52(2006.01)
(86)International application number:
PCT/US2014/025163
(87)International publication number:
WO 2014/197056 (11.12.2014 Gazette  2014/50)

(54)

TWIN TARGET THRUST REVERSER MODULE

DOPPELZIEL-SCHUBUMKEHRERMODUL

MODULE D'INVERSEUR DE POUSSÉE DOUBLE CIBLE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 14.03.2013 US 201361781255 P

(43)Date of publication of application:
20.01.2016 Bulletin 2016/03

(73)Proprietor: United Technologies Corporation
Farmington, CT 06032 (US)

(72)Inventors:
  • SUCIU, Gabriel L.
    Glastonbury, Connecticut 06033 (US)
  • CHANDLER, Jesse M.
    South Windsor, Connecticut 06074 (US)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
WO-A1-86/00862
US-A- 3 057 150
US-A1- 2002 184 874
US-A1- 2007 051 091
US-A1- 2012 137 655
US-B1- 6 381 950
GB-A- 2 445 555
US-A- 4 865 256
US-A1- 2002 184 874
US-A1- 2012 079 805
US-A1- 2012 137 655
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND



    [0001] A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section.

    [0002] Typically, the gas turbine engine is supported under an aircraft wing on either side of the fuselage. However, such under-wing installations may not be compatible with unique aircraft configurations. Accordingly, different mounting locations for the engines such as at the rear of the fuselage are being considered. Different mountings locations present different challenges and require alternate engine configurations.

    [0003] A thrust reverser is utilized once an aircraft has landed, and creates a reverse thrust force to aid in slowing the aircraft. Typical thrust reversers and nozzles are components of the engine nacelle surrounding an under-wing mounted engine (see, for example, US 4865256, US 2012/0137655, and US 2002/0184874). Engines mounted within an aircraft fuselage do not include the same nacelle structures and therefore conventional thrust reversing devices may not be compatible (see, for example, GB 2445555 and US 6381950).

    [0004] Accordingly, it is desirable to design and develop structures that provide thrust reversing and variable nozzle functions for fuselage mounted engine configurations.

    SUMMARY



    [0005] According to a first aspect of the present invention, there is provided a nozzle assembly for a dual gas turbine engine propulsion system according to claim 1.

    [0006] According to a second aspect of the present invention, there is provided an aircraft according to claim 6.

    [0007] Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations.

    [0008] These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0009] 

    Figure 1 schematically shows a proposed aircraft with gas turbine engine mount locations.

    Figure 2a is a schematic view of an example reverse flow gas turbine engine.

    Figure 2b is another schematic view of the example reverse flow gas turbine engine.

    Figure 3 is a perspective view of an example exit nozzle assembly.

    Figure 4 is a partial sectional view of the example exit nozzle assembly in a cruise or in-flight position.

    Figure 5 is a partial sectional view of the example exit nozzle assembly in a deployed position thrust reversing position.

    Figure 6 is a rear perspective view of the example exit nozzle assembly in the cruise or in-flight position.

    Figure 7 is a rear perspective view of the example exit nozzle assembly in an open position.

    Figure 8 is a perspective view of an example not forming part of the claimed invention of an exit nozzle assembly including two actuator systems.

    Figure 9 is a perspective view of an example not forming part of the claimed invention of an exit nozzle assembly including three actuator systems.


    DETAILED DESCRIPTION



    [0010] Referring to Figure 1, an aircraft 10 includes a fuselage 12 with first and second gas turbine engines mounted in an aft end 14. The example aft mounted gas turbine engines 16, 18 include a configuration known as reverse flow. A first fan section 20 of the first gas turbine engine 16 drives propulsive flow through a first nozzle 24. A second fan section 22 driven by the second gas turbine engine 18 drives flow through a second nozzle 26. The first and second nozzles 24, 26 are in a side-by-side orientation and mounted to an aircraft structure 42 at the aft end 14.

    [0011] Referring to Figures 2A and 2B the example first and second gas turbine engines 16, 18 include the fan sections 20, 22 each of which rotates about a respective axis X. The first and second gas turbine engines include core sections 28, 30 that are orientated about a respective axis Y that is angled relative to axis X. Each of the first and second fan sections 20, 22 define a bypass passage 60 that directs airflow around respective ones of the core engine sections 28, 30.

    [0012] The example first and second engines are "reverse flow engines" including a compressor section 36, a combustor section 34 and a turbine section 32. Just as in a typical gas turbine engine the compressor section 34 compresses incoming airflow that is combined with fuel in the combustor section 34. The air /fuel mixture is ignited in the combustor section 34 to produce high energy exhaust gases that drives the turbine section 32. The disclosed turbine section is axially forward of the compressor section 36 and the combustor section 34 and drives a gear reduction 38 that in turn drives the corresponding fan section 20, 22.

    [0013] Referring to Figure 3, the propulsive thrust generated by the fan sections 20, 22 flows through a nozzle assembly 40. The nozzle assembly 40 includes a housing 44 that is attachable to the airframe structure 42. The nozzle assembly 40 includes the first nozzle 24 and the second nozzle 26 controlling propulsive flow from corresponding fan sections 20, 22.

    [0014] First and second upper doors 50a, 50b and first and second lower doors 52a, 52b, which are mounted to corresponding first and second nozzles 24, 26, are movable to vary the cross-sectional area for propulsive flow. The first and second upper doors 50a, 50b and first and second lower doors 52a, 50b are pivotally mounted to the housing 44.

    [0015] Referring to Figures 4 and 5, with continued reference to Figure 3, the upper doors 50a, 50b and the lower doors 52a, 52b include pivots 54 supporting rotation between positions that vary the area through the corresponding nozzle 24, 26. An actuator 58 drives movement of the upper and lower doors 50a, 50b, 52a, and 52b through a linkage 56. A single actuator 58 drives the single linkage 56 to move both the first and second upper doors 50a, 50b and both the first and second lower doors 52a, 52b. The first and second upper and lower doors 50, 52 are movable from the cruise or in-flight position shown in Figure 4 to a thrust reverser position shown in Figure 5.

    [0016] Once an aircraft associated with the nozzle assembly 40 has landed, the actuator 58 drives the linkage 56 to move the first and second upper doors 50a, 50b and lower doors 52a, 52b to the deployed position (Figure 5) in which the doors block the nozzles 24, 26. The first and second engines 16, 18, continue to produce propulsive flow against the deployed doors to generate a reverse thrust tending to slow the aircraft 12.

    [0017] The first and second upper and lower doors 50, 52 close on the engine centerline axes X to redirect airflows through both bypass passages 60 from the respective fan sections 20, 22 as well as the exhaust gas flows from the respective core engine sections 28, 30. The combined and redirected bypass and exhaust gas flows generate a substantial reverse thrust to slow the aircraft 12.

    [0018] Referring to Figures 6 and 7, the same actuator 58 and linkage 56 can be utilized to provide a varying cross-sectional area during flight operations to increase propulsive efficiency of the fan sections 20, 22. The example nozzle assembly 40 is further movable to an open position (Figure 7) from the cruise or in-flight position shown in Figure 6. The position illustrated in Figure 6 is also referred to as a "stowed" position when referring to the thrust reverse function of the nozzle assembly 40.

    [0019] During flight operations the area of each of the nozzles 24, 26 can be increased by pivoting the upper and lower doors such that an aft end of each of the doors moves radially outwardly as compared to the cruise position. The increased area provided by pivoting of the upper and lower doors 50, 52 radially outward generates additional flow area for additional flow indicated by arrows 62, which may aid in maintaining favorable fan operating characteristics such as a fan pressure ratio.

    [0020] The nozzle assembly 40 provides the variable area nozzle function without additional structure as the upper and lower doors 50, 52 are driven by the same actuator 58 and linkage 56 that are utilized for the thrust reverser function.

    [0021] Referring to Figure 8, in an embodiment not forming part of the claimed invention, the example nozzle assembly 40 may also include first and second actuators 58a, 58b for the first upper and lower doors 50a, 52a, independent of the second upper and lower doors 50b, 52b. Corresponding first and second linkages 56a and 56b are provided and driven by the corresponding first and second actuators 58a, 58b. Moreover, the first and second actuators 58a and 58b may also work in unison to open the doors 50a, 50b, 52a and 52b together. In this example, the actuators 58a and 58b are located on opposing sides of the nozzle assembly 40.

    [0022] Referring to Figure 9, in an embodiment not forming part of the claimed invention, the example nozzle assembly 40 may also include first, second and third actuators 58a, 58b and 58c that drive corresponding linkages 56a, 56b and 56c. The third actuator 58c may be arranged between the first nozzle 24 and the second nozzle 26 to provide a further degree of operational redundancy.

    [0023] Accordingly, the example nozzle assembly 40 is mountable to an aircraft structure that provides both a thrust reversing function and a variable area nozzle function to improve propulsive efficiency.

    [0024] Although various example embodiments have been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the invention as defined in the appended claims. For that reason, the following claims should be studied to determine the scope of the invention.


    Claims

    1. A nozzle assembly (40) for a dual gas turbine engine propulsion system comprising:

    a housing (44) mountable to an airframe structure (42) proximate to a first bypass passage (60) of a first gas turbine engine (16) and a second bypass passage (60) of a second gas turbine engine (18), wherein each of the first gas turbine engine (16) and the second gas turbine engine (18) are mounted to an aft end of the airframe structure (42);

    wherein the housing (44) is mountable across the first and second bypass passages (60) corresponding to the first and second gas turbine engines (16, 18) mounted side by side within the airframe structure (42);

    first and second upper doors (50a, 50b) mounted within the housing (44); and

    first and second lower doors (52a, 52b) mounted within the housing (44);

    wherein each of the first and second upper doors (50a, 50b) and the first and second lower doors (52a, 52b) are pivotally mounted to the housing (44) for movement between a stowed position and a deployed position in which airflow through the first and second bypass passages (60) is redirected relative to respective centreline axes of the first and second gas turbine engines (16, 18); and

    further comprising an actuator system (58) including a single actuator configured to drive both the first and second upper doors (50a, 50b) and the first and second lower doors (52a, 52b) between the stowed and deployed positions through a single linkage (56).


     
    2. The nozzle assembly as recited in claim 1, wherein the first and second upper doors (50a, 50b) and the first and second lower doors (52a, 52b) close on a centreline of corresponding ones of the first and second bypass passages (60) to redirect both bypass airflows and core airflows.
     
    3. The nozzle assembly as recited in claim 1 or claim 2, wherein the actuator (58) system is disposed between the first and second engines (16, 18).
     
    4. The nozzle assembly as recited in any preceding claim, wherein the first and second upper doors (50a, 50b) and the first and second lower doors (52a, 52b) are movable from the stowed position to an open position to increase an area of bypass flow.
     
    5. The nozzle assembly as recited in claim 4, wherein each of the first and second upper doors (50a, 50b) and first and second lower doors (52a, 52b) are moved radially outward from the stowed position to the open position.
     
    6. An aircraft comprising:

    a first gas turbine engine (16) driving a first fan section (20) mounted within an aft end of an airframe structure (42);

    a second gas turbine engine (18) driving a second fan section (22) mounted within the aft end of the airframe structure (42) next to the first gas turbine engine (16) and first fan section (20);

    and a nozzle assembly (40) as claimed in claim 1 attached to the airframe structure (42), including first and second exit nozzles corresponding to each of the first and second gas turbine engines (16, 18).


     
    7. The aircraft as recited in claim 6. wherein the first and second upper and lower doors (50a, 50b, 52a, 52b) are movable by the actuator system (58) from the stowed position to an open position to increase a cross-sectional area of the first and second exit nozzles.
     
    8. The aircraft as recited in claim 6, wherein the first and second upper and lower doors (50a, 50b, 52a, 52b) are movable by the actuator system (58) to vary a cross-sectional area of the first and second exit nozzles.
     
    9. The aircraft as recited in any of claims 6 to 8, wherein each of the first and second upper and lower doors (50a, 50b, 52a, 52b) are driven by the actuator system (58) through a linkage (56) to move between the stowed position and the deployed position.
     
    10. The aircraft as recited in any of claims 6 to 9, wherein each of the first and second gas turbine engines (16, 18) comprises reverse flow core engines, each reverse flow core engine respectively including a compressor section (36), a combustor section (34) and a turbine section (32), wherein each of the turbine sections (32) is closest to the corresponding one of the first and second fan sections (20, 22), and wherein, relative to the respective turbine section (32), each of the combustor sections (34) and the compressor sections (36) is positioned further away from the corresponding one of the first and second fan sections (20, 22).
     


    Ansprüche

    1. Düsenbaugruppe (40) für ein Antriebssystem mit einem Doppelgasturbinentriebwerk, umfassend:

    ein Gehäuse (44), das an einer Flugwerkstruktur (42) in der Nähe eines ersten Bypasskanals (60) eines ersten Gasturbinentriebwerks (16) und eines zweiten Bypasskanals (60) eines zweiten Gasturbinentriebwerks (18) montiert werden kann, wobei jedes des ersten Gasturbinentriebwerks (16) und des zweiten Gasturbinentriebwerks (18) an einem hinteren Ende der Flugwerkstruktur (42) montiert ist;

    wobei das Gehäuse (44) über den ersten und zweiten Bypasskanal (60) montiert werden kann, die dem ersten und zweiten Gasturbinentriebwerk (16, 18) entsprechen, die in der Flugwerkstruktur (42) nebeneinander montiert sind;

    eine erste und zweite obere Tür (50a, 50b), die in dem Gehäuse (44) montiert sind; und

    eine erste und zweite untere Tür (52a, 52b), die in dem Gehäuse (44) montiert sind;

    wobei jede der ersten und zweiten oberen Tür (50a, 50b) und der ersten und zweiten unteren Tür (52a, 52b) für eine Bewegung zwischen einer verstauten Position und einer ausgefahrenen Position, in der ein Luftstrom durch den ersten und zweiten Bypasskanal (60) in Bezug auf jeweilige Mittelachsen des ersten und zweiten Gasturbinentriebwerks (16, 18) umgelenkt wird, schwenkbar an dem Gehäuse (44) montiert ist; und

    ferner umfassend ein Betätigungssystem (58), einschließend ein einzelnes Betätigungselement, das konfiguriert ist, um sowohl die erste und die zweite obere Tür (50a, 50b) als auch die erste und zweite untere Tür (52a, 52b) zwischen der verstauten und ausgefahrenen Position durch eine einzige Verknüpfung (56) anzutreiben.


     
    2. Düsenbaugruppe nach Anspruch 1, wobei sich die erste und zweite obere Tür (50a, 50b) und die erste und zweite untere Tür (52a, 52b) auf einer Mittelachse von entsprechenden des ersten und zweiten Bypasskanals (60) schließen, um sowohl die Bypass-Luftströme als auch die Kernluftströme umzulenken.
     
    3. Düsenbaugruppe nach Anspruch 1 oder Anspruch 2, wobei das Betätigungssystem (58) zwischen dem ersten und zweiten Triebwerk (16, 18) angeordnet ist.
     
    4. Düsenbaugruppe nach einem der vorhergehenden Ansprüche, wobei die erste und zweite obere Tür (50a, 50b) und die erste und zweite untere Tür (52a, 52b) von der verstauten Position in eine offene Position bewegt werden können, um eine Fläche des Bypass-Stroms zu vergrößern.
     
    5. Düsenbaugruppe nach Anspruch 4, wobei jede der ersten und zweiten oberen Tür (50a, 50b) und ersten und zweiten unteren Tür (52a, 52b) von der verstauten Position in die offene Position radial nach außen bewegt wird.
     
    6. Luftfahrzeug, umfassend:

    ein erstes Gasturbinentriebwerk (16), das einen ersten Fanabschnitt (20) antreibt, der in einem hinteren Ende einer Flugwerkstruktur (42) montiert ist;

    ein zweites Gasturbinentriebwerk (18), das einen zweiten Fanabschnitt (22) antreibt, der in dem hinteren Ende der Flugwerkstruktur (42) neben dem ersten Gasturbinentriebwerk (16) und dem ersten Fanabschnitt (20) montiert ist;

    und eine Düsenbaugruppe (40) nach Anspruch 1, die an der Flugwerkstruktur (42) angebracht ist, einschließend eine erste und zweite Austrittsdüse, die jedem des ersten und zweiten Gasturbinentriebwerks (16, 18) entsprechen.


     
    7. Luftfahrzeug nach Anspruch 6, wobei die erste und zweite obere und untere Tür (50a, 50b, 52a, 52b) von dem Betätigungssystem (58) von der verstauten Position in eine offene Position bewegt werden können, um eine Querschnittsfläche der ersten und zweiten Austrittsdüse zu vergrößern.
     
    8. Luftfahrzeug nach Anspruch 6, wobei die erste und zweite obere und untere Tür (50a, 50b, 52a, 52b) von dem Betätigungssystem (58) bewegt werden können, um eine Querschnittsfläche der ersten und zweiten Austrittsdüse zu variieren.
     
    9. Luftfahrzeug nach einem der Ansprüche 6 bis 8, wobei jede der ersten und zweiten oberen und unteren Tür (50a, 50b, 52a, 52b) von dem Betätigungssystem (58) durch eine Verknüpfung (56) angetrieben wird, damit sie sich zwischen der verstauten Position und der ausgefahrenen Position bewegt.
     
    10. Luftfahrzeug nach einem der Ansprüche 6 bis 9, wobei jedes des ersten und zweiten Gasturbinentriebwerks (16, 18) Kerntriebwerke mit Umkehrstrom umfasst, wobei jedes Kerntriebwerk mit Umkehrstrom jeweils einen Verdichterabschnitt (36), einen Brennkammerabschnitt (34) und einen Turbinenabschnitt (32) einschließt, wobei jeder der Turbinenabschnitte (32) dem entsprechenden des ersten und zweiten Fanabschnitts (20, 22) am nächsten ist, und wobei in Bezug auf den jeweiligen Turbinenabschnitt (32) jeder der Brennkammerabschnitte (34) und der Verdichterabschnitte (36) weiter weg von dem entsprechenden des ersten und zweiten Fanabschnitts (20, 22) positioniert ist.
     


    Revendications

    1. Ensemble de buses (40) destiné à un système de propulsion de moteur à turbine à gaz double comprenant :

    un carter (44) pouvant être monté sur une structure de cellule d'aéronef (42) à proximité d'un premier passage de dérivation (60) d'un premier moteur à turbine à gaz (16) et d'un second passage de dérivation (60) d'un second moteur à turbine à gaz (18), dans lequel chacun parmi le premier moteur à turbine à gaz (16) et le second moteur à turbine à gaz (18) est monté à une extrémité arrière de la structure de cellule d'aéronef (42) ;

    dans lequel le carter (44) peut être monté à travers les premier et second passages de dérivation (60) correspondant aux premier et second moteurs à turbine à gaz (16, 18) montés côte à côte à l'intérieur de la structure de cellule d'aéronef (42) ;

    des première et seconde portes supérieures (50a, 50b) montées à l'intérieur du carter (44) ; et

    des première et seconde portes inférieures (52a, 52b) montées à l'intérieur du carter (44) ;

    dans lequel chacune des première et seconde portes supérieures (50a, 50b) et des première et seconde portes inférieures (52a, 52b) est montée de manière pivotante sur le carter (44) pour passer d'une position repliée à une position déployée dans lesquelles l'écoulement d'air à travers les premier et second passages de dérivation (60) est redirigé par rapport aux axes médians respectifs des premier et second moteurs à turbine à gaz (16, 18) ; et

    comprenant en outre un système d'actionneur (58) comportant un actionneur unique conçu pour faire passer à la fois les première et seconde portes supérieures (50a, 50b) et les première et seconde portes inférieures (52a, 52b) de la position repliée à la position déployée par l'intermédiaire d'une liaison unique (56).


     
    2. Ensemble de buses selon la revendication 1, dans lequel les première et seconde portes supérieures (50a, 50b) et les première et seconde portes inférieures (52a, 52b) se referment sur une ligne médiane des premier et second passages de dérivation (60) correspondants pour rediriger à la fois les écoulements d'air de dérivation et les écoulements d'air centraux.
     
    3. Ensemble de buses selon la revendication 1 ou la revendication 2, dans lequel le système d'actionneur (58) est disposé entre les premier et second moteurs (16, 18).
     
    4. Ensemble de buses selon une quelconque revendication précédente, dans lequel les première et seconde portes supérieures (50a, 50b) et les première et seconde portes inférieures (52a, 52b) sont mobiles entre la position repliée et une position ouverte pour augmenter une surface d'écoulement de dérivation.
     
    5. Ensemble de buses selon la revendication 4, dans lequel chacune des première et seconde portes supérieures (50a, 50b) et des première et seconde portes inférieures (52a, 52b) sont mobiles radialement vers l'extérieur entre la position repliée et la position ouverte.
     
    6. Aéronef comprenant :

    un premier moteur à turbine à gaz (16) entraînant une première section de soufflante (20) montée à l'intérieur d'une extrémité arrière d'une structure de cellule d'aéronef (42) ;

    un second moteur à turbine à gaz (18) entraînant une seconde section de soufflante (22) montée à l'intérieur de l'extrémité arrière de la structure de cellule d'aéronef (42) à côté du premier moteur à turbine à gaz (16) et de la première section de soufflante (20) ;

    et un ensemble de buses (40), selon la revendication 1, fixé à la structure de cellule aéronef (42), comportant des première et seconde buses de sortie correspondant à chacun des premier et second moteurs à turbine à gaz (16, 18).


     
    7. Aéronef selon la revendication 6, dans lequel les premières et secondes portes supérieures et inférieures (50a, 50b, 52a, 52b) sont mobiles, au moyen du système d'actionneur (58), entre la position repliée et une position ouverte pour augmenter une surface de section transversale des première et seconde buses de sortie.
     
    8. Aéronef selon la revendication 6, dans lequel les premières et secondes portes supérieures et inférieures (50a, 50b, 52a, 52b) sont mobiles, au moyen du système d'actionneur (58), pour faire varier une surface de section transversale des première et seconde buses de sortie.
     
    9. Aéronef selon l'une quelconque des revendications 6 à 8, dans lequel chacune des premières et secondes portes supérieures et inférieures (50a, 50b, 52a, 52b) est entraînée par le système d'actionneur (58) par l'intermédiaire d'une liaison (56) pour passer de la position repliée à la position déployée.
     
    10. Aéronef selon l'une quelconque des revendications 6 à 9, dans lequel chacun des premier et second moteurs à turbine à gaz (16, 18) comprend des blocs réacteurs à écoulement inversé, chaque bloc réacteur à écoulement inversé comportant respectivement une section de compresseur (36), une section de chambre de combustion (34) et une section de turbine (32), dans lequel chacune des sections de turbine (32) est au plus près de la section de ventilateur correspondante parmi les première et seconde sections de ventilateur (20, 22), et dans lequel, par rapport à la section de turbine (32) respective, chacune des sections de chambre de combustion (34) et des sections de compresseur (36) est plus éloignée de la section de ventilateur correspondante parmi les première et seconde sections de ventilateur (20, 22).
     




    Drawing























    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description