Patent Publication Number: US-2023150646-A1

Title: Aircraft floor comprising at least one articulated movable floor part and aircraft equipped with said floor

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of the French patent application No. 2112057 filed on Nov. 15, 2021, the entire disclosures of which are incorporated herein by way of reference. 
     FIELD OF THE INVENTION 
     The present application relates to an aircraft floor comprising at least one articulated movable floor part and to an aircraft equipped with the floor. 
     BACKGROUND OF THE INVENTION 
     According to one embodiment, an aircraft comprises a fuselage, wings and a central wing box positioned in the lower part of the fuselage and connecting the wings to the fuselage. The aircraft also comprises a floor positioned above the central wing box separating the fuselage into an upper region positioned above the floor and a lower region positioned beneath the floor. The floor comprises several beams oriented perpendicular to a longitudinal direction, panels attached to these beams and rails parallel to each other, oriented in the longitudinal direction and attached to the beams. When the upper region is fitted out as a passenger cabin, some of the floor panels situated between the rails can be removed in order to access the lower region from the upper region. Since the rails of a passenger cabin are spaced apart at sufficient intervals, the openings left between the rails by the removable panels are sufficient to provide good accessibility to the lower region. 
     When the upper region is fitted out as a hold for containers, the rails situated on the floor are very close together, meaning that the openings between the rails do not provide easy access to the lower region. Without these openings, the parts situated beneath the floor to either side of the central wing box are inaccessible or difficult to access from the regions situated beneath the floor in front of and to the rear of the central wing box. 
     The aim of the present invention is to partially or completely overcome the disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     To this end, the invention relates to an aircraft floor comprising several beams parallel to each other and perpendicular to a longitudinal direction, several rails parallel to each other and to the longitudinal direction, at least one fixed floor part and at least one floor part that is movable relative to the fixed floor part and that has at least one longitudinal edge parallel to the longitudinal direction. 
     According to the invention, at least two of the beams each comprise a first beam portion secured to a first element chosen from the fixed floor part and the movable floor part and a second beam portion secured to a second element, chosen from the fixed floor part and the movable floor part, different from the first element, the first and second beam portions being aligned, positioned end to end and separated at a cutting plane positioned approximately in line with the longitudinal edge. At least one of the rails comprises at least one first rail portion secured to the movable floor part and at least one second rail portion secured to the fixed floor part, extending the first rail portion. The floor comprises at least one hinge connecting the movable floor part and the fixed floor part, having a pivot axis parallel to the longitudinal direction, the hinge comprising, for at least the two beams, a pivot link connecting the first and second beam portions. 
     Providing a rail portion at the movable floor part makes it possible to obtain a movable floor part that is wide in a transverse direction, facilitating access to the region situated beneath the floor. The hinge allows this movable floor part to be maneuvered easily. It is therefore possible to access beneath the floor, to either side of the central wing box, in order to carry out operations when assembling the aircraft, install equipment or perform maintenance operations during operation of the aircraft. 
     According to another feature, each pivot link comprises: 
     at least one joint plate, connecting the first and second beam portions, which has a first end pressed against the first beam portion and a second end pressed against the second beam portion, 
     a pivot pin, coincident with the pivot axis of the hinge, which passes through the first beam portion and the first end of the joint plate, 
     at least one complete link which connects the second beam portion and the second end of the joint plate. 
     According to another feature, each pivot link comprises two joint plates arranged to either side of the first and second beam portions. 
     According to another feature, each of the first and second beam portions has a web, each joint plate being pressed against a face of the web of each of the first and second beam portions. 
     According to another feature, the first beam portion is secured to the fixed floor part, the second beam portion being secured to the movable floor part. 
     According to another feature, each beam intersecting with the longitudinal edge of the movable floor part, at which the pivot axis is positioned, comprises a cutting plane, positioned approximately at the longitudinal edge, dividing the beam into first and second beam portions connected by a pivot link. 
     According to another feature, the movable floor part is delimited by first and second longitudinal edges parallel to the longitudinal direction and by first and second front and rear transverse edges perpendicular to the longitudinal direction, the front transverse edge being closely spaced apart from and offset slightly towards the front in relation to a first beam, the rear transverse edge being closely spaced apart from and offset slightly towards the rear in relation to a second beam. 
     According to another feature, the floor comprises first and second right- and left-hand lateral edges and first and second movable floor parts, the first movable floor part comprising a left-hand longitudinal edge positioned at the left-hand lateral edge of the floor and a right-hand longitudinal edge closely spaced apart from and offset slightly towards the left in relation to a first rail, the second movable floor part comprising a right-hand longitudinal edge positioned at the right-hand lateral edge of the floor and a left-hand longitudinal edge closely spaced apart from and offset slightly towards the right in relation to a second rail. 
     The invention also relates to an aircraft comprising a floor according to one of the preceding features. 
     According to another feature, the aircraft comprising a central wing box and a main landing gear casing, the movable floor part is positioned above the central wing box and/or the main landing gear casing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages will become apparent from the description of the invention which follows, which description is given only as a non-limiting example, with reference to the accompanying drawings in which: 
         FIG.  1    is a side view of an aircraft, 
         FIG.  2    is a longitudinal cross-section of a part of the fuselage of the aircraft shown in  FIG.  1   , 
         FIG.  3    is a perspective view of the beams and rails of a floor of an aircraft hold showing one embodiment of the invention, 
         FIG.  4    is a perspective view of a lateral region of the floor shown in  FIG.  3   , 
         FIG.  5    is a front view of a lateral region of the floor shown in  FIG.  3   , 
         FIG.  6    is a perspective view of a hinge of a movable floor part integrated into a floor of an aircraft hold showing one embodiment of the invention, and 
         FIG.  7    is a perspective view of a hinge between two portions of a beam of a floor of an aircraft hold showing one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG.  1   , an aircraft  10  comprises a fuselage  12  that extends between a nose cone  14  and a tail cone  16 , as well as wings  18  arranged to either side of the fuselage  12  and connected to the latter by a central wing box  20 . 
     Hereinafter in the description, a longitudinal axis  22  of the aircraft  10  corresponds to the horizontal axis (when the aircraft  10  is on the ground) that extends from the nose cone  14  to the tail cone  16  of the aircraft  10 . A longitudinal direction is a direction parallel to the longitudinal axis  22 . A longitudinal plane is a plan comprising an axis that is parallel to the longitudinal axis  22 . A median longitudinal plane PLM is a vertical longitudinal plane passing through the longitudinal axis  22 . A transverse plane is a plane perpendicular to the longitudinal axis  22 . 
     The notions of front (Av) and rear (Ar) refer to the direction of flow of air outside the aircraft during flight, which travels from the front towards the rear. 
     As shown in  FIGS.  2  and  3   , the fuselage  12  also comprises at least one front fuselage section  24  situated in front of the central wing box  20 , a main landing gear casing  26  offset towards the rear in relation to the central wing box  20 , at least one rear fuselage section  28  situated to the rear of the main landing gear casing  26  and a floor  30 , positioned above the central wing box  20 , that extends from the front fuselage section  24  to the rear fuselage section  28 . 
     According to one application, the floor  30  separates the fuselage into an upper region situated above the floor  30  and a lower region situated beneath the floor  30 . The upper region situated above the floor  30  forms a hold  32  in which at least one container  34  can be stored (shown with dashed lines in  FIG.  2   ). The floor  30  has first and second lateral edges  30 . 1 ,  30 . 1  adjacent to the fuselage  12 , symmetrical to the median longitudinal plane PLM. 
     According to one embodiment, the floor  30  comprises several beams  36  parallel to each other and perpendicular to the longitudinal direction and several rails  38  attached to the beams  36 , parallel to each other and to the longitudinal direction. The floor  30  comprises panels  40  (partially visible in the  FIG.  4   ) positioned between the rails  38  and configured to close the spaces between the rails  38 . These panels  40  rest on the beams  36  and/or the rails  38  and are fixed thereto. 
     The fuselage  12  comprises a load-bearing structure  42 , such as longerons or props, for example, supporting the floor  30 . 
     According to one configuration, the floor  30  comprises at least one fixed floor part  44  and at least one movable floor part  46  that is movable relative to the fixed floor part  44 , configured to bring the hold  32  into communication with the lower region situated beneath the floor  30 . In the region of the fixed floor parts  44 , the beams  36  of the floor  30  are fastened to the load-bearing structure  42  of the fuselage  12 . In the region of each movable floor part  46 , the beams  36  of the floor  30  rest on the load-bearing structure  42  but are not fastened thereto. 
     Each movable floor part  46 , which is approximately rectangular, is delimited by first and second longitudinal edges  46 . 1 ,  46 . 2  parallel to the longitudinal direction and by first and second front and rear transverse edges  46 . 3 ,  46 . 4  perpendicular to the longitudinal direction. 
     According to one arrangement, the floor  30  comprises several movable floor parts  46 ,  46 ′ adjoining the first and second lateral edges  30 . 1 ,  30 . 2  of the floor  30 ; for each of the movable floor parts  46 , one of its longitudinal edges  46 . 1 ,  46 . 2  is overlaid on or coincident with one of the lateral edges  30 . 1 ,  30 . 2  of the floor  30 . The movable floor parts  46 ,  46 ′ are arranged symmetrically in relation to the median longitudinal plane PLM. 
     The floor  30  comprises at least one movable floor part  46  covering a region situated above the central wing box  20  and/or the main landing gear casing  26 . According to one configuration, the floor  30  comprises, at each of its lateral edges  30 . 1 ,  30 . 2 , a single movable floor part  46 , its front transverse edge  46 . 3  being situated vertically in line with a first transverse plane PT 1  which separates the front fuselage section  24  and the central wing box  20 , its rear transverse edge  46 . 4  being situated vertically in line with a second transverse plane PT 2  which separates the rear fuselage section  28  and the main landing gear casing  26 . According to another configuration, the floor  30  comprises, at each of its lateral edges  30 . 1 ,  30 . 2 , several movable floor parts  46 , juxtaposed in the longitudinal direction, which extend from the first transverse plane PT 1  to the second transverse plane PT 2 . 
     According to one arrangement, at least one movable floor part  46  comprises a left-hand longitudinal edge  46 . 1  positioned at the left-hand lateral edge  30 . 1  of the floor  30 , a right-hand longitudinal edge  46 . 2  closely spaced apart from and offset slightly towards the left in relation to a rail  38 A, a front transverse edge  46 . 3  closely spaced apart from and offset slightly towards the front in relation to a first beam  36 A and a rear transverse edge  46 . 4  closely spaced apart from and offset slightly towards the rear in relation to a second beam  36 B. 
     At least one movable floor part  46 ′ comprises a right-hand longitudinal edge  46 . 2  positioned at the right-hand lateral edge  30 . 2  of the floor  30 , a left-hand longitudinal edge  46 . 1  closely spaced apart from and offset slightly towards the left in relation to a rail  38 , a front transverse edge  46 . 3  closely spaced apart from and offset slightly towards the front in relation to a first beam  36 A and a rear transverse edge  46 . 4  closely spaced apart from and offset slightly towards the rear in relation to a second beam  36 B. 
     To give an idea of the scale, each movable floor part  46  has a width (the dimension considered in a transverse direction) greater than 70 cm, in the region of 1 m, and a length (the dimension considered in the longitudinal direction) greater than 1 m. 
     According to one embodiment, each beam  36  extends from the first lateral edge  30 . 1  to the second lateral edge  30 . 2 . According to one configuration, each beam  36  has an I-shaped cross-section comprising a web  36 . 1  and two flanges  36 . 2 ,  36 . 3  positioned at each of the ends of the web  36 . 1 . 
     Each rail  38  has a substantially constant profile along its entire length. Each rail extends from the front fuselage section  24  to the rear fuselage section  28 . For example, the rail  38  may have a I-shaped, T-shaped, inverted L-shaped, C-shaped or other cross-section. 
     Naturally, the invention is not limited to these cross-sections for the beams  36  and the rails  38 . 
     Irrespective of the embodiment, several beams  36  extend over at least one fixed floor part  44  and over at least one movable floor part  46  and comprise a first beam portion  48 . 1  secured to a first element chosen from the fixed part  44  and the movable floor part  46  and a second beam portion  48 . 2  secured to a second element, chosen from the fixed floor part  44  and the movable floor part  46 , different from the first element. The first and second beam portions  48 . 1 ,  48 . 2  are aligned, positioned end to end and separated at a cutting plane positioned approximately in line with one of the longitudinal edges  46 . 1 ,  46 . 2  of the movable floor part  46 . Depending on the number of movable floor parts  46 , some beams may comprise two or three beam portions. 
     According to one configuration, the first beam portion  48 . 1  is secured to the fixed floor part  44 , the second beam portion  48 . 2  being secured to the movable floor part  46 . 
     The cutting planes of the beams  36 , positioned approximately in line with the same longitudinal edge  46 . 1 ,  46 . 2  of a movable floor part  46 , are substantially coplanar. 
     According to one arrangement, when the floor  30  comprises two movable floor parts  46  positioned to either side of a fixed floor part  44 , some beams  36  each comprise a first central beam portion  48 . 1  secured to the fixed floor part  44  and second and third beam portions  48 . 2  positioned in the continuation of each end of the first beam portion  48 . 1  and secured to the movable floor parts  46 . 
     At least one rail  38  extends over at least one fixed floor part  44  and at least one movable floor part  46  and comprises a first rail portion  50 . 1  secured to the fixed floor part  44  and a second rail portion  50 . 2  secured to the movable floor part  46 , the first and second rail portions  50 . 1 ,  50 . 2  being aligned, positioned end to end and separated at a cutting plane positioned approximately in line with one of the transverse edges  46 . 3 ,  46 . 4  of the movable floor part  46 . According to one configuration, some rails  38  positioned at a movable floor part  46  each comprise a first rail portion  50 . 1  secured to the movable floor part  46  and second and third rail portions  50 . 2 ,  50 . 3  positioned in the continuation of each end of the first rail portion  50 . 1  and secured to the fixed floor part  44  of the floor  30 . Naturally, the invention is not limited to this configuration. 
     According to one particular feature, the floor  30  comprises at least one hinge  52  connecting at least one movable floor part  46  and the fixed floor part  44 . This hinge  52  has a pivot axis A 52  parallel to the longitudinal direction and positioned approximately in line with the cutting planes of the beams  36 . 
     According to one arrangement, each movable floor part  46  is connected to the fixed floor part  44  by a hinge  52 . 
     For at least two beams  36  having cutting planes positioned approximately in line with a longitudinal edge  46 . 1 ,  46 . 2 , the hinge  52  comprises a pivot link  54 , one for each of the two beams  36 , connecting the two beam portions  48 . 1 ,  48 . 2  positioned to either side of the cutting plane. 
     According to one configuration, each beam  36  intersecting with one of the longitudinal edges  46 . 1 ,  46 . 2  of the movable floor part  46  comprises a cutting plane positioned approximately at the longitudinal edge  46 . 1 ,  46 . 2  dividing the beam  36  into first and second beam portions  48 . 1 ,  48 . 2  connected by a pivot link  54  which has a pivot pin coincident with the pivot axis A 52  of the hinge  52 . 
     According to one embodiment shown in detail in  FIG.  7   , each pivot link  54  comprises: 
     at least one joint plate  56 , connecting the first and second beam portions  48 . 1 ,  48 . 2 , which has a first end  56 . 1  pressed against a first face of the web  36 . 1  of the first beam portion  48 . 1  and a second end  56 . 2  pressed against a first face of the web  36 . 1  of the second beam portion  48 . 2 , 
     a pivot pin  58 , coincident with the pivot axis A 52  of the hinge  52 , which passes through the web  36 . 1  of the first beam portion  48 . 1  and the first end  56 . 1  of the joint plate  56 , 
     at least one complete link  60  which connects the web  36 . 1  of the second beam portion  48 . 2  and the second end  56 . 2  of the joint plate  56 . 
     The pivot pin  58  comprises a cylinder  58 . 1  and two abutments  58 . 2  positioned at each end of the cylinder  58 . 1 , the cylinder  58 . 1  and the two abutments  58 . 2  being configured in such a way as to keep each joint plate  56  pressed against the web  36 . 1  of the first beam portion  48 . 1 . According to one embodiment, the pivot pin  58  is a bolt, the screw of the bolt corresponding to the cylinder and to one of the two abutments, the nut of the bolt corresponding to the other abutment. 
     Furthermore, the web  36 . 1  of the first beam portion  48 . 1  has a through-hole configured to receive the cylinder  58 . 1  of the pivot pin  58 . In parallel, the first end  56 . 1  of each joint plate  56  has a through-hole configured to receive the cylinder  58 . 1  of the pivot pin  58 . 
     The complete link  60  is obtained by bonding, bolting, crimping or any other assembly technique. 
     According to one embodiment, each pivot link  54  comprises two joint plates  56 ,  56 ′ arranged to either side of the webs  36 . 1  of the first and second beam portions  48 . 1 ,  48 . 2 . 
     According to one configuration, the pivot pin  58  is provided at the first beam portion  48 . 1  secured to the fixed floor part  44 , each joint plate being connected by a complete link  60  to the second beam portion  48 . 2  secured to the movable floor part  46 . 
     According to another configuration, the pivot pin  58  is provided at the second beam portion  48 . 2  secured to the movable floor part  46 , each joint plate being connected by a complete link  60  to the first beam portion  48 . 1  secured to the fixed floor part  44 . 
     Each movable floor part  46  comprises at least one rail portion extended by at least one rail portion secured to the fixed floor part  44 . Therefore, each movable floor part  46  has a considerable width (the dimension considered in the transverse direction) which facilitates access to the region situated beneath the floor  30 . The hinge  52  allows the movable floor part  46  to be maneuvered easily by making it pivot in order to expose an opening that allows access to the region situated beneath the floor  30 . 
     Providing a pivot link  54  for each beam  36  intersecting with the pivot axis A 52  helps obtain a strong link between the movable floor part  46  and the fixed floor part  44 , capable of withstanding the weight of the containers  34  positioned on the floor  30 . 
     While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.