Patent Application
20230339612
The present disclosure belongs to the field of aeronautical structures and analogs, in particular primary structures for on-board equipment and supplies, and relates more particularly to a frame for an aircraft seat shell obtained by assembling planar cut structural parts, as well as an associated manufacturing method.
In an aircraft such as an airplane, every on-board piece of equipment is sized and qualified to meet requirements that are functional, safety-related and economical at the same time. For example, for a passenger seat, this results in a trade-off essentially between the mechanical strength and the mass of the primary structure of the seat. Other criteria such as fire resistance are also taken into account.
In the field of civil aviation more particularly, there are standards and regulations establishing a whole series of criteria that passenger seat structures must meet for certification thereof. For example, the primary structures such as the shells of the passenger seats must have a given mechanical resistance to the different stresses in service, in particular impacts and vibrations, as well as flame-retardant and fire-resistance properties.
In addition, the weight constraint, which is essential for airlines because it directly affects the operating cost of the aircraft.
As a general rule, most on-board structures (seats, cabinets, etc.) currently consist of composite panels assembled by metal connecting parts. For example, these panels have a honeycomb sandwich structure, abbreviated as Nida, which enhances their mechanical resistance and guarantees maximum lightweight.
Nida composite panels are complex to manufacture, expensive and have a long manufacturing cycle. Hence, their use systematically requires starting the operations of defining the seat and fitting out the aircraft cabin very early in the action plan of the considered program.
There are many designs for aircraft seats. For example, the document US2012085863A1 discloses a seat with a complex design wherein the structure consists of different elements (plates, beams and multiform fastening and joining means). Other designs are characterized by a predominance of plate elements and are more suited for energy absorption in the event of impact, document US2005145597A1 gives an example thereof.
In these solutions, the use of plate-type structural elements strongly limits the variety of possible shapes. Therefore, making of free-form shell structures quickly becomes very complex and subject to the vagaries of the use of Nida panels for this kind of items, namely the duration and the cost of manufacture.
Nevertheless, the need of airlines offering higher classes, such as business class or first class, in terms of aesthetic shapes, especially for space dividers, remains paramount.
To date, there is no viable alternative to Nida panels for the targeted applications.
The present disclosure aims to overcome the drawbacks of the prior art set out hereinabove, in particular to provide an alternative solution for making aircraft seat primary structures, with more or less complex three-dimensional shapes, by assembling planar cut parts with relatively simple shapes.
The disclosure also aims to provide an alternative to honeycomb composite panels, widely used in the aeronautical industry, whose costs are high and whose manufacturing cycles are long.
To this end, an object of the present disclosure is a frame for an aircraft seat primary structure, comprising longitudinal parts and transverse parts spaced apart and assembled together, said parts having varied shapes and dimensions so as to replicate a general three-dimensional x shape of the primary structure. This structure is remarkable in that the longitudinal and transverse parts are planar and in that each of them includes at least one joint, the said parts being assembled by their joints.
According to a particularly advantageous aspect of the disclosure, each longitudinal part is provided with a plurality of joints distributed along an edge of said part, each of said joints cooperating with a joint of a transverse part. Similarly, each transverse part is provided with a plurality of joints distributed along an edge of said part, each of said joints cooperating with a joint of a longitudinal part.
According to one embodiment, the mean planes of the transverse parts are substantially parallel and the mean planes of the longitudinal parts are substantially perpendicular to the mean planes of said transverse parts. Thus, the longitudinal and transverse parts can be assimilated respectively to stringers and bulkheads, the stringers being connected by parallel bulkheads to form the frame.
According to an advantageous embodiment, each joint has a depth substantially equal to half a local width of the part including said joint.
More particularly each assembly between a longitudinal part and a transverse part is of the T-shaped half-timber type.
Advantageously, the longitudinal and transverse parts are plate elements, i.e. they have one dimension, the thickness, which is negligible compared to the other two, namely the length and the width.
According to the disclosure, the frame may also include auxiliary planar parts of any shape as well as planar hooking and fastening parts.
For example, the auxiliary parts and the hooking and fastening parts may be fastened to the rest of the frame by means such as tenons and mortises.
According to one embodiment, the longitudinal and transverse parts are metallic.
More generally, all of the planar parts of the frame can be metallic.
The present disclosure also relates to an aircraft seat primary structure, comprising a frame as described and a covering shell wrapping said frame, and an airplane-type aircraft seat, comprising such a primary structure.
The present disclosure also relates to a method for manufacturing a frame as described, for an aircraft seat primary structure, comprising:
Advantageously, the method further comprises a step of rigidly fastening the obtained assembly by welding, gluing, clipping or any other conventional technique.
The fundamental concepts of the disclosure that have just been disclosed hereinabove in their most elementary form, other details and features will appear more clearly upon reading the following description and with reference to the appended drawings, giving as a non-limiting example an embodiment of a frame and of an associated manufacturing method in accordance with the principles of the disclosure.
The figures are given for merely illustrative purposes for the understanding of the disclosure and do not limit the scope thereof. The different elements are not necessarily represented at the same scale. In all figures, identical or equivalent elements bear the same reference numeral.
It is thus illustrated in:
It should be noted that some well-known assemblies and methods are described herein to avoid any insufficiency or ambiguity in the understanding of the present disclosure.
In the embodiment described hereinafter, reference is made to a metal frame formed by cut and assembled planar parts, intended mainly for a passenger seat separation shell in an aircraft cabin. This non-limiting example is given for a better understanding of the disclosure and does not exclude the manufacture of a similar frame in any material and for other aircraft on-board equipment or supply.
In the rest of the description, the term “frame” refers to a structural set formed by an assembly of non-adjoining elements mostly elongated.
According to the illustrated example, the primary structure 100 is that of a passenger seat in the “front” cabin, in other words of higher class such as business class, and therefore has volumes suited for more comfort and for a separation of the installed passenger from the rest of the cabin for more privacy. Of course, the disclosure can be applied to any other aircraft seat or equipment having more or less complex three-dimensional shapes.
The brief and partial presentation made hereinabove of the primary structure of the seat allows just defining the context of application of the disclosure, the main object of which is the frame.
Thus, the frame 10 replicates the general shape of the covering shell 20 thanks to the shapes and dimensions of the assembled planar parts 11 and 12. These geometric shapes and dimensions are determined beforehand on the basis of a digital model of the seat, for example, as will be explained later on.
Referring to
Indeed, the longitudinal 11 and transverse 12 parts are assembled by their joints 111 and 121 like a T-shaped half-timber assembly, better known in old naval constructions of wooden vessels.
The joints 111 and 121 correspond to straight indentations, i.e. having a U-shape.
Furthermore, the parts 11 and 12 may have different thicknesses, in which case the joints 111 and 121 must have suitable widths 11 and 12. In the example of
Conversely, the joint 121 must have a width 12 substantially equal to the local thickness of the part 11. This dimensional correspondence enables interlocking of the parts 11 and 12 with a minimum functional clearance, or mounting by interference when the widths of the joints are substantially smaller than the thicknesses of the parts.
The joints 111 and 121 can be oriented differently along the parts 11 and 12.
Preferably, only the joints 121 of the transverse parts 12 can be inclined with respect to the local normals. In turn, the joints 111 of the longitudinal parts 11 are normal so that said longitudinal parts, or stringers, are necessarily perpendicular to the transverse parts, or bulkheads, after assembly. More specifically, the mean planes of the stringers 11 remain perpendicular to the mean planes of the bulkheads 12, regardless of their orientations, these being determined according to constraints related to the final shape of the frame 10.
In view of the foregoing, it should be easily understood that the present disclosure provides a considerable advantage by allowing obtaining a very wide variety of shapes simply thanks to planar parts 11 and 12 which are assembled by joints 111 and 121 and whose shapes and dimensions have been determined beforehand.
Examples of a longitudinal part 11 and a transverse part 12 of the frame are given in
Furthermore, the frame 10 may include any other planar auxiliary part 13 to address some functional and/or structural problems.
The frame 10 may also include planar hooking and fastening parts 14a and 14b as well as connecting means 15 as represented in
Incidentally, the frame 10 may include almost planar parts 16, indicated in
Thus, the frame according to the concepts of the present disclosure offers great modularity and allows obtaining complex 3D shapes starting from elementary 2D parts defined and prepared beforehand.
The frame 10 can be manufactured by a method comprising:
The step of defining the longitudinal 11 and transverse 12 parts forming the frame consists in determining the shapes and the dimensions of said parts as well as their number and distribution in the frame. To this end, a model of the primary structure 100 for which the frame is intended can be used. Thus, it is for example possible to define the parts 11 and 12 from longitudinal and transverse sections made in the CAD (Computer Aided Design) model of the primary structure.
The other planar parts of the frame 10, namely the auxiliary parts 13 of any shape and the hooking and fastening parts 14a and 14b, can be defined in the same manner.
The step of cutting the parts, including the complementary parts, can be carried out by any cutting technique used in mechanical manufacturing such as laser cutting or water jet cutting depending on the used material. It should be noted that it is preferable to proceed by laser cutting in view of the performances, in terms of efficiency and accuracy, obtained by this technique, and this on different materials (metal, plastic, etc.).
The step of assembling the parts of the frame 10 takes place according to the operations of joining by the joints explained hereinabove.
Finally, the obtained assembly is rigidly fastened by welding, gluing, clipping or by any other conventional means of mechanical manufacturing.
It should be noted that making a frame from simple independent parts greatly facilitates the maintenance and the repair of the aircraft seat, and considerably limits its cost. Indeed, all it needs is to replace some faulty longitudinal or transverse parts, unlike a one-piece composite structure in which damages could be problematic and require the replacement of the entire structure.
It clearly arises from the present description that the different planar parts of the frame can be made differently without departing from the scope of the disclosure, defined in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2007492 | Jul 2020 | FR | national |
This application is a National Stage of International Application No. PCT/EP2021/070034, having an International Filing Date of 16 Jul. 2021, which designated the United States of America, and which claims priority from and the benefit of French Patent Application No. 2007492 filed on 17 Jul. 2020, the disclosures of which are incorporated herein by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/070034 | 7/16/2021 | WO |
