Abstract:
An energy absorber for aircraft includes one or more energy absorber elements and a housing, whereby the energy absorber elements can absorb crash impulses by plastic deformation within the housing.

Description:
RELATED APPLICATIONS  
       [0001]    This application claims the benefit of German Patent Application No. 10 2006 007 029.1 filed Feb. 15, 2006, and of U.S. Provisional Application No. 60/773,762 filed Feb. 15, 2006, the disclosures of which are hereby incorporated herein by reference. 
       FIELD OF THE INVENTION  
       [0002]    The present invention relates to energy absorbers for aircraft. In particular, the present invention relates to an energy absorber for an aircraft, the use of such an energy absorber in an aircraft, and a method for energy absorption in an aircraft. 
         [0003]    In aircraft, holders or attachment elements for holding and attaching inboard devices, such as ceiling liners, overhead bins, or monuments, are used. Rigid attachment elements may, in particular in the event of intense accelerations, such as those that may occur in the event of severe turbulence or, for example, also with an emergency landing, transmit resulting acceleration forces directly from the primary structure of the aircraft over the holder to the attached inboard device. Likewise, all forces or accelerations acting on the inboard device are transferred directly via the holder or the holder system to the aircraft structure. 
         [0004]    Known holders and the inboard devices attached thereto may statically placed on the basis of static load or maximum service loads. A breakdown of the holder, such as for example, by breaking or bursting out from the inboard device based on excessive acceleration forces may occur, which may lead to damage to the holder, the inboard device, or the primary structure of the aircraft and further, may endanger or injure the passengers or lead to impairment with a possible evacuation. 
       SUMMARY OF THE INVENTION 
       [0005]    It is an object of the present invention to provide an energy absorber for aircraft, which provides a secure attachment of inboard devices or other devices of the aircraft, also under intense mechanical loads. 
         [0006]    According to one embodiment of the present invention, an energy absorber for an aircraft is provided, the energy absorber including a first energy absorber element and a second energy absorber element, a third energy absorber element and a fourth energy absorber element, all four for absorption of an acceleration energy by plastic deformation, and a housing. The plastic deformation of the energy absorber elements takes place within the housing. The first energy absorber element is disposed adjacent to the second energy absorber element, and the third energy absorber element is disposed adjacent to the fourth energy absorber element, so that the respective, adjacent energy absorber elements are braced against one another, i.e. supported by one another, during a rolling motion. 
         [0007]    By means of the energy absorber elements, which are integrated at least partially in the housing, the mechanical load on the inboard device, which is connected by the energy absorber with a primary structure of the aircraft, and which can be, for example, a luggage bin mounted over the passengers, may be limited. For example, the energy absorber may be designed for absorbing acceleration energy resulting from movement of the aircraft. By absorbing acceleration energies, the force transmissions from the primary structure of the aircraft to the inboard device or from the inboard device to the primary structure may be reduced. This may lead to an increased passive safety in the cabin. In addition, by using the energy absorber of the present invention with energy absorber elements, the construction of the inboard device may be designed in a material- or weight-savings manner, since the maximally occurring mechanical loads are reduced. This permits a weight-optimization of all components involved on the load curve (for example, inboard components, holder, and primary structure). In addition, with a statically overruled system, a uniform load distribution may be made possible, in particular with a structure deformed by load. 
         [0008]    By the use of multiple energy absorber elements, which are arranged parallel to one another and lie flat on one another, the force levels may be increased. At the same time, the existing space may be better used and the differently positioned energy absorber elements (for example, in the form of sheets or plates) may affect a more favorable force distribution on the deck layers by the now existing two force lines. 
         [0009]    Thus, with the energy absorber of the present invention, crash impulses, like those that may occur with an emergency landing, may be at least partially absorbed. The resulting force impact accordingly may not be transferred completely to the inboard device, rather damped additionally or absorbed partially to a defined force level, so that malfunction may be prevented. 
         [0010]    By the principle of plastic deformation, it may further be possible to absorb multiple crash impulses, and in the forward as well as in the reverse direction. In other words, the energy absorber may work in two directions (specifically, are extracted from the housing and displaced into the housing) and thereby absorb impacts in different directions. 
         [0011]    The outwardly acting forces may be reduced, such that (with suitable construction) a separate housing can be eliminated and can be integrated in the geometry to be mounted (for example, honeycomb plates with a hatrack). 
         [0012]    There may be no surfaces subjected to friction. 
         [0013]    According to a further exemplary embodiment of the present invention, the energy absorber further includes a fifth energy absorber element and a sixth energy absorber element, which are arranged adjacent to one another, so that they brace against one another during rolling motion. 
         [0014]    Thus, a plurality of absorber pairs can be used which roll against one another, whereby the force level may be further increased and a flatter construction of the energy absorber may be possible. 
         [0015]    According to a further exemplary embodiment of the present invention, a seventh energy absorber element and an eighth energy absorber element are provided, whereby the seventh energy absorber element is inlaid in the first energy absorber element, and whereby the eighth energy absorber element is inlaid in the second energy absorber element. 
         [0016]    In this manner, it may be ensured that the absorbed force is distributed better on the housing. 
         [0017]    According to a further embodiment of the present invention, the housing includes a first cover plate or cover sheet, a second cover plate or cover sheet, and a fixed support for the second energy absorber element and the first energy absorber element. 
         [0018]    According to a further embodiment of the present invention, the first energy absorber element has a longitudinal slot or slit, whereby the housing further has an intermediate wall, which is mounted in the area of the slit. 
         [0019]    By slitting the sheet and the division of the housing by the intermediate walls into multiple chambers made possible thereby, the maximum forces on the deck layers may be reduced substantially. 
         [0020]    According to a further embodiment of the present invention, the energy absorber further includes a first attachment area and a second attachment area, whereby the first attachment area is designed for attachment of the energy absorber to the primary structure and whereby the second attachment area is designed for attachment of the energy absorber to the inboard device. 
         [0021]    The attachment areas may make possible, for example, a simple assembly. In this regard, the energy absorber first may be fixedly mounted to a hull- or ceiling surface or to a support element of the primary structure. Next, then, an inboard device element may be connected permanently at the second attachment area with the energy absorber. 
         [0022]    According to a further exemplary embodiment of the present invention, the attachment of the energy absorber to the primary structure or to the inboard device takes place by means of a force- or positive-locking connection. 
         [0023]    Therefore, an energy absorber may be provided, for example, which may be mounted simply. The first attachment region, for example, additionally may have a profile, for example, in the form of a claw element, which is inserted onto a rectangular section of a support. In this regard, the claw element may be designed, for example, such that the energy absorber is held to the support with this insertion so that its fixed weight is held. For final attachment of the energy absorber, the energy absorber then may be fixed by means of screws, rivets or self-locking pins or similar means to the support. 
         [0024]    According to a further exemplary embodiment of the present invention, the energy absorber further has an adjustment element. The adjustment element may change the bending radius of the energy absorber element and therewith, the lever arm. In this manner, a change of the force level may be provided (for example, a variable constant load level or a progressive or declining performance may thus be adjustable). 
         [0025]    In this manner, the force progression may be freely adjusted by continuous change of the cover sheet distance. 
         [0026]    In addition, the force-path progression may be adapted individually by a contour adaptation of the cover sheet. In addition, the energy absorber itself can be structured or contoured, in order to individually adjust a further adaptation of the force-path progression. 
         [0027]    For example, the cover sheet can have a bulge or hump, so that the energy absorber element may be forced to an additional bending, which may affect likewise the force level. 
         [0028]    According to a further exemplary embodiment of the present invention, the energy absorber has an energy absorption direction, whereby not until exceeding of a minimal force (force limiter), which acts in the direction of the energy absorption direction, an energy absorption occurs through the energy absorber. 
         [0029]    The interior device (e.g. a facility or compartment or the like) can be supported substantially fixedly with correspondingly minimal load, so that it may be suitable for normal on-board operation. With increased load, such as through an intense impact of force, a damping is established, in which for example, the energy absorber is pulled in the absorption direction from the housing (or is pushed into the housing). In this manner, correspondingly intense force impacts may effectively be absorbed. 
         [0030]    According to a further exemplary embodiment of the present invention, the use of an energy absorber in an aircraft is provided. 
         [0031]    According to a further exemplary embodiment of the present invention, a method for energy absorption in an aircraft is provided, including a pulling out of a first energy absorber element, a second energy absorber element, a third energy absorber element, and a fourth energy absorber element from a housing, and an absorption of an acceleration energy by plastic deformation of the energy absorber elements within the housing during the pulling out, whereby the first energy absorber element is arranged adjacent to the second energy absorber element, and whereby the third energy absorber element is arranged adjacent to the fourth energy absorber element, so that respective, adjacent energy absorber elements are braced against one another during rolling motion. 
         [0032]    Further embodiments of the invention are provided in the dependent claims. 
         [0033]    Next, the invention will be described in greater detail with regard to exemplary embodiments in reference to the drawings. 
     
    
     
       SHORT DESCRIPTION OF THE FIGURES  
         [0034]      FIG. 1A  shows a schematic cross-sectional representation of the energy absorber according to one exemplary embodiment of the present invention. 
           [0035]      FIG. 1B  shows a schematic representation of the energy absorber of  FIG. 1A  in plan view. 
           [0036]      FIG. 2A  shows a schematic cross-sectional representation of an energy absorber. 
           [0037]      FIG. 2B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 2A . 
           [0038]      FIG. 3A  shows a schematic cross-sectional representation of an energy absorber. 
           [0039]      FIG. 3B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 3A . 
           [0040]      FIG. 4A  shows a schematic cross-sectional representation of a further energy absorber. 
           [0041]      FIG. 4B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 4A . 
           [0042]      FIG. 5A  shows a schematic cross-sectional representation of an energy absorber. 
           [0043]      FIG. 5B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 5A . 
           [0044]      FIG. 6A  shows an energy absorber in a schematic cross-sectional representation according to an exemplary embodiment of the present invention. 
           [0045]      FIG. 6B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 6A . 
           [0046]      FIG. 6C  shows a detail enlargement of a region of the energy absorber of  FIG. 6A . 
           [0047]      FIG. 7A  shows a schematic cross-sectional representation of an energy absorber. 
           [0048]      FIG. 7B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 7A . 
           [0049]      FIG. 8A  shows a schematic cross-sectional representation of an energy absorber with an adjustment element. 
           [0050]      FIG. 8B  shows a further schematic cross-sectional representation of the energy absorber of  FIG. 8A . 
           [0051]      FIG. 8C  shows an exemplary force-path-progression of the energy absorber according to the configuration of  FIGS. 8A ,  8 B. 
           [0052]      FIG. 8D  shows the energy absorber of  FIGS. 8A ,  8 B with an actuated adjustment element. 
           [0053]      FIG. 8E  shows a corresponding force-path-progression of the energy absorber according to the configuration of  FIG. 8D . 
           [0054]      FIG. 9A  shows an energy absorber with an adjustment element. 
           [0055]      FIG. 9B  shows a corresponding force-path-progression of the energy absorber according to the configuration of  FIG. 9A . 
           [0056]      FIG. 9C  shows the energy absorber of  FIG. 9A  with a different actuated adjustment element. 
           [0057]      FIG. 9D  shows the corresponding force-path-progression of the energy absorber according to the configuration of  FIG. 9C . 
           [0058]      FIG. 10A  shows an energy absorber with an adjustment element. 
           [0059]      FIG. 10B  shows the energy absorber of  FIG. 10A  in a further cross-sectional representation. 
           [0060]      FIG. 10C  shows the corresponding force-path-progression of the energy absorber according to the configuration of  FIGS. 10A ,  10 B. 
           [0061]      FIG. 10D  shows the energy absorber of  FIG. 10A  with actuated adjustment elements. 
           [0062]      FIG. 10E  shows the corresponding force-path-progression of the energy absorber according to the configuration of  FIG. 10D . 
           [0063]      FIG. 11A  shows an energy absorber with actuated adjustment elements. 
           [0064]      FIG. 11B  shows the corresponding force-path-progression of the energy absorber according to the configuration of  FIG. 11A . 
           [0065]      FIG. 11C  shows a further energy absorber with actuated adjustment elements. 
           [0066]      FIG. 11D  shows the force-path-progression of the energy absorber according to the configuration of  FIG. 11C . 
       
    
    
       [0067]    In the following description of the figures, the same reference numerals are used for the same or similar elements. 
         [0068]    The representations in the figures are schematic and not to scale. 
       DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
       [0069]      FIG. 1A  shows a schematic cross-sectional representation of an energy absorber according to an exemplary embodiment of the present invention. The energy absorber  100  has a lower housing region  101  and an upper housing region  102 , between which the energy absorber element is mounted. 
         [0070]    The energy absorber  100 , in which this energy absorber elements  1  are installed, is subdivided basically into so-called single deckers with a sheet or plate (for absorption) or with multiple sheets or plates placed in one another and so-called multiple deckers with two or more sheets or plates running opposite to one another (which can comprise respectively again multiple sheets or plates placed in one another). 
         [0071]    Thus, multiple sheets may be nested in one another, in order to achieve for example an optimization of the cover layer load, better volume use or increased force level. 
         [0072]    In addition, the energy absorber  100  includes a fixed support  103  for the energy absorber element  1  and force impact points  105 - 112 ,  115 . 
         [0073]      FIG. 1B  shows the energy absorber of  FIG. 1A  in a representation rotated at 90°. The upper housing part or double-decker sheet  102  has a bore  113  for attachment, for example, to the primary structure of the aircraft. The energy absorber element  1  has a bore  114  for attachment, for example, to an inboard device part of the aircraft. If a force acts now on the housing in the direction of the arrow  116  and a force acts on the absorber element  1  in the opposite direction 1   17 , then the absorber element is pulled out from the housing by plastic deformation upon exceeding a known minimal force. Thus, energy is absorbed. 
         [0074]    The absorption functions also in the reverse direction, as specifically the energy absorber element  1  is pressed into the housing. The first impact points  105  to  112  and  115  serve on the one hand for connection of the cover plates  101 ,  102  and for distribution of the occurring forces (symbolized by force line  118  and arrows  119 ,  120 ). 
         [0075]    The structure shown in  FIG. 1  represents the basic form of the single decker. Here, the energy absorber element  1  is braced against the cover layers  101 ,  102  and is transformed upon reaching the trigger force. 
         [0076]      FIGS. 2A ,  2 B shows cross-sectional representations of an energy absorber according to a further exemplary embodiment of the present invention. This structure is principally designed like the structure in  FIG. 1 . By means of the slots of the sheet  1  and the subdivision of the housing  102 ,  101  made possible in this manner by intermediate walls  202  into multiple chambers, the forces may be greatly reduced or uniformly distributed. Reference numeral  201  represents a slot in the sheet, in which an intermediate wall  202  runs. 
         [0077]      FIGS. 3A ,  3 B show a further energy absorber according to a further exemplary embodiment of the present invention in two cross-sectional representations. This structure can be viewed as an independent deformation principle. Since here, however, preferably only one energy absorber element  1  is deformed, this structure is attributed likewise to the single-decker. The sheet is passed multiple times around rollers  301 ,  302 ,  303 ,  304 ,  305 ,  306 ,  307 . The rollers should be designed to be rotatable, in order to hold the frictional effect at a minimum. 
         [0078]      FIGS. 4A ,  4 B show an energy absorber according to a further exemplary embodiment of the present invention, which belongs to the structure “double deck”. 
         [0079]    Here, the first energy absorber element  1  is braced on one side against the cover plate  102 . A second energy absorber element  3  is provided, which is braced on the other side against the lower cover plate  101 . The energy absorber elements  1 ,  3  are deformed upon reaching the tripper force and roll against one another. 
         [0080]      FIGS. 5A ,  5 B shows an energy absorber according to a further exemplary embodiment of the present invention. This structure is designed principally like the structure of  FIG. 4 . By the placement of two or more sheets  1 ,  2  or  3 ,  4 , the force level may be increased. For example, larger loads can therefore be absorbed. At the same time, one uses the space better and the differently positioned, sheets affect a favorable force distribution on the cover plates  101 ,  102  through the now existing two force lines  118 . 
         [0081]      FIGS. 6A ,  6 B,  6 C shows a further embodiment of the energy absorber. Here, respectively, two (or more) sheets are placed in one another ( 1 ,  2  or  3 ,  4  or  5 ,  6  or  7 ,  8 ). In addition, the different groups of inlaid sheets are placed respectively over one another. The sheet pair  1 ,  2  is braced with a rolling motion against the sheet pair  3 ,  4  and the sheet pair  5 ,  6 , is braced with a rolling motion against the sheet pair  7 ,  8 . 
         [0082]    The structural space here may be used very favorably. The multiple sheets lying over one another acts by their arrangement itself like cover plates and may reduce therefore the forces acting on the cover layers  101 ,  102 . 
         [0083]    In addition, through the adjacent placement of such sheets, the thickness of the energy absorber  100  (that is, the spacing of both cover plates  101 ,  102 ) with constant force progression may be reduced. This may enable an integration of the energy absorber in a sandwich plate of the aircraft cabin structure, for example, which may result in turn in reduction of the housing. 
         [0084]      FIGS. 7A ,  7 B show an energy absorber according to a further exemplary embodiment of the present invention. This structure is designated by a slim design. Here, the individual energy absorber elements  1 ,  2 ,  3 ,  4 ,  9 ,  10  are connected to one another via a central tension rod  701 . The differently positioned sheets may affect a favorable force distribution on the cover plates  101 ,  102  through the now existing three force lines  1181 ,  1182 ,  1183 . 
         [0085]      FIGS. 8A through 9D  show an energy absorber with an adjustment element according to a further exemplary embodiment of the present invention. The force progression may be adjusted freely by continuous change of the cover plate distance. This adjustment element system may be used for the single cover principle as well as for the double or multiple cover principle. 
         [0086]    The adjustment element system includes a first adjustment element  801 , a second adjustment element  802 , and a cover plate  803 , which can be displaced by actuation of both adjustment elements  801 ,  802 . 
         [0087]    By actuation of the adjustment elements  801 ,  802 , the cover plate  803  can be displaced, such that the energy absorber element  1  is squeezed together more or less intensely. 
         [0088]    In the configuration shown in  FIGS. 8A ,  8 B, the uniform, substantially constant force-path-progression of  FIG. 8C  may be provided. 
         [0089]    In the position shown in  FIG. 8D  (here the adjustment elements  801 ,  802  are screwed in more strongly, so that the cover plate  803  presses together the energy absorber element  1  more strongly), the force-path-progression shown in  FIG. 8D  may be provided (at higher level than in  FIG. 8C ). 
         [0090]    In the position shown in  FIG. 9A , in which the cover plate  803  is positioned at an incline, the force progression shown in  FIG. 9B  may be provided. Here, after expenditure of a minimal force, the force progression is not constant, rather decreases upon pulling out of the strip  1 . On the contrary, the force progression increases upon pushing in of the strip. 
         [0091]    The cover plate  803  may also have a different form, for example, a hump or bulge  808 , which leads to bending of the sheet  1  still further in the region  809 , thereby changing the force-path-progression accordingly. 
         [0092]    In the configuration shown in  FIG. 9C , a reverse force progression (see  FIG. 9D ) is provided, in which upon pulling out of the sheet  1 , the force expended therefore increases (and vice versa). 
         [0093]      FIGS. 10A through 11D  show a double decker system with adjustment elements  801 ,  802 ,  805 ,  806  and cover sheets  803 ,  807 . 
         [0094]    The force progression resulting from the configuration of  FIGS. 10A ,  10 B is shown in  FIG. 10C . The force runs constantly here upon pulling out or pushing in of the sheets  1 ,  3 . 
         [0095]    If the adjustment elements  801 ,  802 ,  805 ,  806  are screwed in (see  FIG. 10D ), an increased force progression is provided (see  FIG. 10E ). 
         [0096]    If the adjustment elements are screwed in strongly in a different manner, as shown in  FIG. 11A , a force progression that decreases upon pulling out is provided (see  FIG. 11B ). 
         [0097]    If in contrast the adjustment elements are screwed in counter to the configuration of  FIG. 11A  (see  FIG. 11C ), an increased force progression is provided upon pulling out of the strips  1 ,  2  (see  FIG. 11D ). 
         [0098]    The adjustment elements may be positioned also via hydraulic tappet rods, eccentric disks or electric adjustment drives instead of by screws (see  FIGS. 11A and 11C ). 
         [0099]    Thus, the force level of the absorption may be adjusted also very quickly and/or by automation to the individual situation. 
         [0100]    Naturally, also the use of other materials may be possible, for example flexible, deformable plastics or other flexible, deformable materials/material mixtures. 
         [0101]    The shown energy absorber may also be used as an energy absorber in so-called tie-rods. Further applications are, for example: 
         [0102]    Energy absorber in tie rods of hatrack chains. The particular effect is the transfer of forces of the released holder onto the hatrack arranged in front of it and therewith a potential of redundancy of these retaining concepts. Essentially, these principles are useable where a permanent, positive force-fit connection (defined kinematically) is required. 
         [0103]    Energy absorber in undercarriages. 
         [0104]    Energy absorber with belt systems. 
         [0105]    Energy absorber in rudder linkage for large landing flaps and rudders. 
         [0106]    Energy absorber for seats. 
         [0107]    Energy absorber with the securing of freight. 
         [0108]    Integration of energy absorbers in the attachment points of monuments of the cabin. 
         [0109]    Energy absorber for APUs, in particular for attachment of the APU (“Auxiliary Power Unit”). 
         [0110]    Energy absorber for separating walls or aircraft arrester nets. 
         [0111]    By changing the geometry of the absorber elements, the bending radius and the material properties, the force levels may be varied. In addition, the force level may be adjustable by changing spacing of the cover sheets. A permanent frictional connection exists. The system is impervious to environmental conditions. In addition, the system is insensitive to diagonal pull (that is, for example, diagonal with reference to the arrow in  FIG. 9A ), which can occur for example with a crash by deformation of the primary structure. Here, a relative displacement of elements/components can occur, which could have as a result a deviation in the pullout direction. 
         [0112]    It should be noted that the term “comprising” does not exclude other elements or steps and the “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. 
         [0113]    It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.