Abstract:
This invention relates to a device for monitoring the synchronism of one or more flaps of aircraft wings, wherein the device includes a control cable which is connected with the flaps such that the control cable follows the flap movement. In accordance with the invention, the path of installation of the control cable extends from a first point to a second point, one or both of which are arranged on non-movable structural components of the aircraft wing.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a device for monitoring the synchronism of one or more flaps of aircraft wings, wherein the device includes a control cable which is connected with the flaps such that the control cable follows the flap movement. 
     For influencing the lift and the drag coefficient of the aircraft wings, airplanes are equipped with various flaps which change the aerodynamic properties of the aircraft wings in the desired way. In accordance with the present application, the term “flap” is meant to include any such component which is movable with respect to fixed structural components of the aircraft wing and with which aerodynamic properties can be influenced. Examples include leading-edge flaps and landing flaps. 
     It is desired, for instance, that for take-off and landing the aircraft has slow flight properties, whereas in cruise flight the leading-edge flaps and landing flaps must be positioned such that fast flight properties can be realized. During operation, the undesired case may happen that malfunctions in the drive system of the flaps occur, which depending on the kind of malfunction can lead to skewing, misalignment or even the loss of individual flaps or flap segments. This involves the disadvantage that the aerodynamic properties of the wings are impaired in an undesired way, for instance by rolling moments or also by consequential damages upon loss of the flaps. 
     To be able to detect such undesired conditions in time, it is known to monitor the synchronism of flaps of a high-lift system by a control cable mechanism. Such systems are known from U.S. Pat. No. 5,680,124 and EP 0 726 201 A1. In the systems known from these references, the cable ends of the control cable abut against the movable flaps to be monitored. In the case of a malfunction during the movement of one or more flaps, the distance between these stop points is increased, which can be detected by a suitable sensor system. One disadvantage in the system known from the prior art consists in that due to the arrangement of the control cable stop points on the flaps the entire sensor mechanism must follow the movement of the flaps. Another disadvantage consists in that in the systems known from the prior art it is merely possible to detect malfunctions of the movement of two adjacent flaps of an aircraft wing. The known system cannot be used, if only one flap per wing is present or must be monitored. 
     Finally, it must be regarded as disadvantageous that the drive mechanisms at the outer and inner flap ends, i.e. the outermost and innermost drive mechanisms, cannot be monitored by the known system, as the control cable does not extend up to the vicinity of the same. 
     SUMMARY OF THE INVENTION 
     Therefore, it is the object underlying the present invention to develop a device for monitoring the synchronism of one or more flaps of an aircraft wing to the effect that the same has a comparatively simple construction and has an extended functionality as compared to the system known from the prior art. 
     In accordance with the invention, this object is solved by a device with the features herein. Accordingly, it is provided that the path of installation of the control cable extends from a first point to a second point, one or both of which are arranged on non-movable structural components of the aircraft wing. Such configuration of a monitoring device provides for performing the monitoring also for the case that for each aircraft wing only one flap is provided or only one flap must be monitored. In addition, the system can also be used for monitoring the flap ends both outboard and inboard, as the path of installation of the control cable also can extend beyond the flap ends up to the non-movable structural components. In so far, the device in accordance with the invention includes a functional improvement as compared to the known monitoring system, without the complexity of the monitoring device being increased. 
     Another advantage is obtained in that the sensor element need not necessarily be arranged on the movable flap, which is disadvantageous in so far as the connection of the necessary electric line to the sensor element need not be guided over the gap of variable extension between fixed and movable structural parts of the wing. 
     In a further aspect of the invention it is provided that for each half wing, i.e. half span, one or also more control cables are provided. If a plurality of control cables are provided for each half wing, different groups of flaps or also different individual flaps can separately be subjected to monitoring. 
     In a further aspect of the invention it is provided that the path of installation of the control cable extends such that it extends from a first point through the one or more flaps to a second point such that during the trouble-free operation of the flaps the length of the path of installation is independent of the flap position. Thus, it is conceivable that in the retracted condition of the flaps the length of the path of installation corresponds or substantially corresponds to the length of the path of installation in the extended condition of the flaps, so that the control cable has the same state of tension in both positions. However, if the movement of a flap proceeds asynchronously, for instance because one of the drive mechanisms or the drive mechanism of the flap does not operate or does not operate in the desired way, the path of installation is changed in its length, so that the control cable is tensioned or relaxed, which by means of a suitable sensor element, e.g. a switch, a distance sensor and the like, can be converted into an electric signal, which in turn activates for instance safety mechanisms of the system. It is conceivable, for instance, that a signal is generated, which leads to the stopping of the drive system, and/or that a corresponding warning signal is generated in the cockpit of the aircraft. 
     It is likewise possible that in the trouble-free operation the length of the path of installation is changed with a change of the flap position by a certain amount. In this case it is also possible that it is detected whether during the movement of the flaps from one to another position this certain amount of the change in length is achieved, which can suitably be measured directly or indirectly. If this is the case, the trouble-free operation would be inferred. If this is not the case, it can be detected that a malfunction exists, which—as explained above—can lead to a stopping of the system and/or to the generation of a warning signal. 
     In a further aspect of the invention it is provided that the first point and the second point in direction of movement of the flaps are offset with respect to each other. It is conceivable, for instance, that one of the points is arranged at or in the vicinity of the edge of the aircraft wing and that the other of the points by contrast is set back from the edge of the aircraft wing. Thus, it is possible that the path of installation of the control cable is independent of the position and movement of the flaps, as during extension of the flaps the path of installation on one side of the flaps is increased by the amount by which it is decreased on the other side of the flaps. 
     In a further aspect of the invention it is provided that the control cable is guided over deflection rollers, which are arranged at the lateral edges of the flaps. It is also conceivable to guide the control cable over deflection rollers which are not arranged at the lateral edges of the flaps, but are set back with respect to the lateral edges. 
     By choosing the distance between the deflection rollers and the flap edges, it is possible to adjust the response sensitivity of the system. The closer the deflection rollers are located to the flap edge, the greater the influence of an asynchronous course of the flaps on the length of the path of installation, i.e. the greater the response sensitivity of the device. Thus, a variation of the response sensitivity can be adjusted by positioning the deflection rollers. It is conceivable to construct the deflection rollers so as to be variable in position, in order to be able to individually adjust the response sensitivity. 
     In a further aspect of the invention it is provided that the control cable runs over the entire width or an essential part of the width of the flaps. 
     In a further aspect of the invention it is provided that the control cable furthermore is guided over fixed structures, such as an engine bracket. The device in accordance with the present invention does not exclude such arrangement, but provides for detecting the asynchronous course of one or more flaps in this case as well. 
     It can be provided that the control cable is guided over structure-mounted deflection rollers. These deflection rollers serve to arrange the path of installation of the control cable around the fixed structure. 
     It is conceivable that on both sides of the fixed structure flaps are located, with which the control cable is connected or through which the control cable extends. Furthermore, it can be provided that the structure-mounted deflection rollers are arranged such that in the trouble-free operation of the flap the length of the path of installation of the control cable from one flap adjoining the fixed structure to the other flap adjoining the fixed structure is not changed or is changed by a certain amount. It can be provided that at least two of the structure-mounted deflection rollers are arranged offset with respect to each other in the direction of movement of the flaps. Thus, it is possible that the length of the path between one of these structure-mounted deflection rollers and the deflection roller of the adjoining flap is increased or decreased by the amount by which the length of the path of installation from the other structure-mounted roller to the deflection roller of the flap adjoining the same is decreased or increased. On the whole, it can thus be achieved that the path of installation is independent of the flap position also in the case of structure-mounted deflection rollers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages are explained by means of an embodiment illustrated in the drawing, in which: 
         FIG. 1 : shows the arrangement of the control cable with retracted and extended flaps, 
         FIG. 2 : shows a simplified representation of the arrangement as shown in  FIG. 1 , 
         FIG. 3 : shows an arrangement of the control cable system with synchronizing error of a flap with low response sensitivity, 
         FIG. 4 : shows an arrangement of the control cable system with synchronizing error of a lap with high response sensitivity, 
         FIG. 5 : shows an arrangement of the control cable system with synchronizing error on the inboard flap end during retraction/extension, and 
         FIG. 6 : shows an arrangement of the control cable system via a fixed structure, for instance an engine bracket. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIG. 1 , the reference numerals  1 ,  2 ,  3  designate three flaps arranged one beside the other, which are for instance leading-edge flaps or landing flaps.  FIG. 1 , upper representation, shows the flaps  1 ,  2 ,  3  in the retracted condition. Reference numeral  100  designates the structure-mounted part of the illustrated half wing of an aircraft. 
     The path of installation of the control cable  10  extends between the points  20 ,  30 , which both are stationary, i.e. arranged on structure-mounted parts  100  of the aircraft wing. The reference numerals  40  designate deflection rollers, which are arranged on the flaps  1 ,  2 ,  3  and are moved together with the same. 
     The reference numerals  50  finally designate drive units for moving the flaps  1 ,  2 ,  3 , of which drive units two are provided per flap in the embodiment shown in  FIG. 1 . 
     As can furthermore be taken from  FIG. 1 , the control cable  10  is firmly connected with the one end point  20  of the path of installation. Via a spring  65 , the other end of the control cable  10  is connected with the other end point  30  of the path of installation. This leads to the fact that the length of the path of installation can be varied within certain limits. If the length of the path of installation is changed, this will lead to the spring being loaded or relieved, which can be measured by suitable sensors. 
     As can furthermore be taken from  FIG. 1 , two deflection rollers  60 ,  60 ′ are arranged on the structure-mounted, i.e. non-moved structural component  100  of the half wing, one of which ( 60 ′) is located in the vicinity of the wing edge and the other one ( 60 ) is set back with respect to the same. This leads to the fact that the length of the path of installation is not changed during extension of the flaps ( FIG. 1 , lower representation), which in turn results in the tension of the spring  65  remaining unchanged. 
       FIG. 2  shows the arrangement of  FIG. 1  in a simplified representation, wherein identical components or components having the same function are provided with the same reference numerals as in  FIG. 1 . 
     In the case of a synchronizing error of one or more flaps  1 ,  2 ,  3 , the length of the path of installation is changed, hence also the tension of the control cable  10  and thus also of the spring  65 , which can be measured in a suitable way.  FIG. 3  shows this condition, in which there is a synchronizing error of the flap shown on the right both during retraction and during extension, respectively. In both cases, an elongation of the path of installation is obtained as compared to the synchronous condition as shown in  FIG. 1  and  FIG. 2 , and thus an increase in the spring force, which can be measured. 
     For reasons of better clarity, the reference numerals are omitted in  FIGS. 3 ,  4  and  5 . 
     In the embodiment shown in  FIG. 3  and in  FIG. 4 , all deflection rollers are disposed on the flaps and not on structure-mounted components of the wing. In the terminal regions facing each other, the flaps each include deflection rollers, which are, however, arranged at a certain distance from the flap edges, as shown in  FIG. 3 . This results in a comparatively low response sensitivity, as the change in length of the path of installation is smaller than in the case of the corresponding deflection rollers being located directly at or closer to the edge of the flap, as is the case in the Figure. This Figure likewise shows a synchronizing error of the flap shown on the right during retraction and extension, respectively, but with a high response sensitivity of the system. 
     Due to the fact that in accordance with the present embodiment at least one of the end points of the path of installation is stationary, it is possible to also detect synchronizing errors at the flap end. Such embodiment is shown in  FIG. 5 , in which a malfunction of the drive unit occurs at the flap shown on the right. In the embodiment shown here, the malfunction exists on the inboard flap end of the flap shown on the right during retraction and extension, respectively. 
       FIG. 6  shows an embodiment of the present invention, in which the control cable is guided over structure-mounted rollers  80 ,  81 ,  82 , which pass for instance over an engine bracket  110 . In  FIG. 6 , the structure-mounted rollers are designated with the reference numerals  80 ,  81 ,  82 . On both sides of the engine bracket  110 , the flaps  3 ,  4  are located, with the flap  4  forming the inboard flap of the illustrated half wing. 
     In this embodiment, too, the end points  20 ,  30  of the path of installation of the control cable  10  are stationarily arranged. 
     From the two structure-mounted rollers  80 ,  82 , the control cable runs to a deflection roller  90 ,  91  of the respectively adjacent flap  3  or  4 . The deflection rollers  90 ,  91  are arranged such that on the side of the flap  3  an elongation of the path between the structure-mounted deflection roller  80  and the adjacent deflection roller  90  of the adjacent flap  3  is obtained during extension of the flaps, and on the side of the flap  4  a shortening of the path between the structure-mounted deflection roller  82  and the adjacent deflection roller  91 , as is shown in  FIG. 6 . On the whole, it is achieved that by means of the illustrated arrangement, the length of the path of installation between the deflection rollers  90 ,  91  via the structure-mounted deflection rollers  80 ,  81 ,  82  of the flaps  3  and  4  remains constant in the trouble-free operation of the arrangement. 
     The example of  FIG. 6  shows an engine bracket  110  as a non-movable structure. Of course, the invention is not restricted thereto. Other stationary structures, such as landing gear structures or also the wing assembly itself, can also be configured as non-movable structures. In the latter case, the system can be installed through the fuselage to the opposed half wing. This means a minimum of system complexity (one cable, one sensor for the entire wing) and hence a maximum of reliability at low cost.