AIRCRAFT WITH FOLDING MECHANISM

Abstract

An aircraft with folding mechanism, the aircraft including a fuselage, optionally a payload and/or landing gear attached to the fuselage, at least two longitudinal beams attached to the fuselage that preferably extend parallel to each other and parallel to a first aircraft axis, with lifting units attached to each of the longitudinal beams. At least one crossbeam is attached to the fuselage, and preferably extending parallel to a second aircraft axis and at right angles with respect to the longitudinal beams, with lifting units attached to the crossbeam. The longitudinal beams are rotatably attached to the fuselage by at least one respective first pivot joint configured for pivoting the longitudinal beams around a respective first pivot axis to a pivoted position. The crossbeam is rotatably attached to the fuselage, preferably by at least one second pivot joint, for pivoting the crossbeam around a second pivot axis to a pivoted position.

Claims

1. An aircraft (1) with folding mechanism, the aircraft (1) comprising: a fuselage (2); at least two longitudinal beams (7.1, 7.2) attached to said fuselage (2), with a plurality of lifting units (3) attached to each of said longitudinal beams (7.1, 7.2); at least one crossbeam (8) attached to said fuselage (2) that extends at an angle with respect to said longitudinal beams (7.1, 7.2), with a plurality of lifting units (3) attached to said crossbeam (8); said longitudinal beams (7.1, 7.2) are rotatably attached to said fuselage (2) by at least one respective first pivot joint configured for pivoting said longitudinal beams (7.1, 7.2) around a respective first pivot axis to a pivoted position (7.1′, 7.2′); and said crossbeam (8) is rotatably attached to said fuselage (2) by at least one second pivot joint, configured for pivoting said crossbeam (8) around a second pivot axis to a pivoted position (8′).

2. The aircraft (1) of claim 1, wherein said lifting units (3) comprise at least one respective rotor (3b), said rotors (3b) being arranged in a common rotor plane, for at least one of said longitudinal beams (7.1, 7.2) or said crossbeam (8), respectively.

3. The aircraft (1) of claim 1, wherein said crossbeam (8) is arranged above said longitudinal beams (7.1, 7.2) along a vertical axis (z) of the aircraft (1).

4. The aircraft (1) of claim 1, wherein said longitudinal beams (7.1, 7.2) have multiple branches, said lifting units (3) being located at least at one of respective branching points or end-points of said branches.

5. The aircraft (1) of claim 1, wherein said crossbeam (8) has multiple branches, said lifting units (3) being located at least at one of respective branching points or end-points of said branches.

6. The aircraft (1) of claim 1, wherein the lifting units (3) comprise rotors (3b) that are attachable in the pivoted position relative to said longitudinal beams (7.1, 7.2) and said crossbeam (8), respectively, by at least one of a strap system, protection attachments, or dust covers.

7. The aircraft (1) of claim 6, wherein the rotors (3b) located on said longitudinal beams (7.1, 7.2) are attachable with their blades oriented in parallel with said longitudinal beams (7.1, 7.2), and the rotors (3b) located on said crossbeam (8) are attachable with their blades oriented in parallel with said crossbeam (8), transversely to said longitudinal beams (7.1, 7.2).

8. The aircraft (1) of claim 1, further comprising a plurality of connector elements (5) for interconnecting one of said longitudinal beams (7.1, 7.2) with said crossbeam (8) or one of said longitudinal beams (7.1, 7.2) with another one of said longitudinal beams (7.1, 7.2).

9. The aircraft (1) of claim 8, wherein at least one said connector element (5) is rotatably attached either to one of said longitudinal beams (7.1, 7.2) or to said crossbeam (8) by a third pivot joint (5b) configured for rotating said connector element (5) against said one of said longitudinal beams (7.1, 7.2) or said crossbeam (8).

10. The aircraft (1) of claim 9, further comprising a quick release mechanism (5a) configured to secure said connector elements (5) on said crossbeam (8), said quick release mechanism (5a) comprising a pin (9) for passing through alignable through-holes (5c; 8a, 8ab) in said connector elements (5) and said crossbeam (8) or respective brackets (8a) attached to said crossbeam (8).

11. The aircraft (1) of claim 1, wherein said longitudinal beams (7.1, 7.2), in a pivoted position (7.1′, 7.2′) thereof, enclose said fuselage (2).

12. The aircraft (1) of claim 1, further comprising a resilient mechanism configured to support a pivoting motion of said longitudinal beams (7.1, 7.2).

13. The aircraft (1) of claim 1, further comprising a detachable crossbeam (8) jig that provides said second pivot joint.

14. The aircraft (1) of claim 1, further comprising an attachment configured to fix said crossbeam (8) to said longitudinal beams (7.1, 7.2) in said pivoted positions.

15. The aircraft (1) of claim 1, wherein ther is an even number of the lifting units N=2k, with k∈N, each of the lifting units comprises at least one rotor (3b), and: for N=6, two of the lifting units (3) are arranged on said crossbeam (8), at opposite ends thereof, and two of the lifting units (3) are arranged on each one of the two longitudinal beams (7.1, 7.2), at opposite ends thereof; for N=8, four of the lifting units (3) are arranged on said crossbeam (8), and two of the lifting units (3) are arranged on each one of the two longitudinal beams (7.1, 7.2), at opposite ends thereof; for N=18, six of the lifting units (3) are arranged on said crossbeam (8), and six of the lifting units (3) are arranged on each one of the two longitudinal beams (7.1, 7.2).

16. The aircraft (1) of of claim 1, further comprising at least one of a payload (2′) or a landing gear (2″) attached to said fuselage (2).

17. The aircraft (1) of of claim 1, wherein the longitudinal beams extend parallel to each other and parallel to a first axis (x) of the aircraft (1).

18. The aircraft (1) of of claim 1, wherein the crossbeam extends parallel to a second axis (y) of the aircraft (1) and at right angles to said longitudinal beams.

19. The aircraft (1) of of claim 4, wherein the lifting units are located in at least one triangular configuration.

20. The aircraft (1) of of claim 5, wherein the lifting units are located in at least one triangular configuration.

Description

BRIEF DESCRIPTION FO THE DRAWINGS

[0053] Additional features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the appended drawings.

[0054] FIG. 1 shows a prior art aircraft configuration;

[0055] FIG. 2 shows a schematical representation of an aircraft according to the invention;

[0056] FIG. 3 shows different aircraft configurations according to the invention;

[0057] FIG. 4 shows the location of quick release and rotation interface in the aircraft of FIG. 2;

[0058] FIG. 5 shows a first step during folding the ring connectors of the aircraft of FIG. 2;

[0059] FIG. 6 shows an embodiment of the quick release mechanism for ring connector elements;

[0060] FIG. 7 shows a second step during folding of the aircraft of FIG. 2;

[0061] FIG. 8 shows the aircraft of FIG. 2 with folded longitudinal beams (third step during folding of the aircraft);

[0062] FIG. 9 shows details of the aircraft structure;

[0063] FIG. 10 shows a fourth step during folding of the aircraft of FIG. 2;

[0064] FIG. 11 shows a detail of the aircraft cable routing; and

[0065] FIG. 12 shows a final folding state of the aircraft of FIG. 2.

DETAILED DESCRIPTION

[0066] FIG. 1 has been described further up; it shows a prior art aircraft 1.

[0067] In the following Figures, same reference numerals denote the same elements or elements that do at least provide a similar function. In the case of identical elements, not all of them are provided with a reference numeral for increased intelligibility.

[0068] FIG. 2 schematically shows the new aircraft design without a central hub. Aircraft 1 comprises a fuselage 2, under which can be attached a payload and/or a landing gear (cf. FIG. 12). Aircraft 1 further has at least two longitudinal beams 7.1, 7.2 attached to said fuselage 2, preferably above and sideways of said fuselage 2, as shown. Said longitudinal beams 7.1, 7.2 extend parallel to each other and parallel to a longitudinal axis of the aircraft (denoted x in FIG. 2). There is a plurality of lifting units 3 attached to each of said longitudinal beams 7.1, 7.2, only one of which is denoted by means of reference numerals 3, 3b (wherein 3b indicates a corresponding rotor by means of a corresponding propeller sweep area). Each lifting unit is thus symbolized by a dashed circle in FIG. 2. All of the rotors 3b located on the longitudinal beam 7.1, 7.2 can be arranged in a common rotor plane.

[0069] At least one crossbeam 8 is also attached to said fuselage 2, preferably above said fuselage 2 and above said longitudinal beams 7.1, 7.2, and it extends parallel to a transverse axis of the aircraft 1 (denoted y in FIG. 2) at right angles with respect to said longitudinal beams 7.1, 7.2. A plurality of lifting units is attached to said crossbeam 8, as shown. All of the rotors 3b located on the crossbeam 8 can be arranged in a common rotor plane, which rotor plane can be (but need not be) the same as for the rotors located on said longitudinal beams 7.1, 7.2. Said longitudinal beams 7.1, 7.2 are rotatably attached to said fuselage 2 by means of at least one respective first pivot joint (cf. FIG. 8) devised for pivoting said longitudinal beams 7.1, 7.2 around a respective first pivot axis to a pivoted position, which first pivot axis is parallel to said longitudinal axis (x). Furthermore, said crossbeam 8 is rotatably attached to said fuselage 2, preferably by means of at least one second pivot joint (cf. FIG. 10), for pivoting said crossbeam 8 around a second pivot axis to a pivoted position, which second pivot axis is parallel to a vertical axis (z) of aircraft 1.

[0070] Both the longitudinal beams 7.1, 7.2 and the crossbeam 8 have a branched configuration and are shaped in the form of the letter “Y” towards their respective free ends (i.e., away from the fuselage 2). Furthermore, there are additional branches that connect the upper Y legs, thus creating a triangular beam configuration at the extremities of the longitudinal beams 7.1, 7.2 and the crossbeam 8. In analogy with FIG. 1, individual branches or beams of the Y-shaped beam portions 3c are denoted by reference numerals 3c′, which encompasses those beams that interconnect the upper extremities of the Y legs. However, there is no central hub in FIG. 2, and every beam, i.e., longitudinal beams 7.1, 7.2 and crossbeam 8, comprises two Y-shaped portions 3c at its extremities. The lifting units 3 are located in the corners (apexes) of said triangular beam configurations. As in the prior art, elements 5 (ring connectors or connector elements) interconnect neighbouring Y-shaped beam portions 3c to form an overall ring-shaped configuration for increased stability.

[0071] While crossbeam 8, in the embodiment shown, is perfectly symmetric with respect to its longitudinal axis (from free end to free end, i.e., left to right along axis y in FIG. 2), the longitudinal beams 7.1, 7.2 are of asymmetrical configuration in this respect, as can be seen from FIG. 2. In fact, they are devised as identical parts and arranged symmetrically with respect to a middle transverse axis (parallel to crossbeam 8). They are further arranged in mutually mirrored fashion (with respect to a longitudinal axis of the aircraft 1; cf. axis x in FIG. 2).

[0072] Preferably, pivot axes for (downward) folding of said longitudinal beams 7.1, 7.2 are arranged parallel to an axis of longest straight extension of said longitudinal beams 7.1, 7.2. These pivot axes are depicted by means of dash-dotted lines PA in FIG. 2. This is advantageous since it permits to fold down said longitudinal beams 7.1, 7.2 without having any rotor 3b extend upwardly beyond a plane defined by said pivot axes PA. This will become clearer further down (cf., e.g., FIGS. 8 and 12).

[0073] FIG. 3 illustrates this basic design principle for aircraft 1 with (from left to right) six, eight, and eighteen lifting units 3, respectively.

[0074] FIG. 4 shows the aircraft 1 of FIG. 2 and the location of quick release interfaces 5a as well as of rotation interfaces (or pivot joints) 5b in connection with the ring connectors 5. Upon release of the respective quick release interfaces 5a, said ring connectors 5 can be rotated around said rotation interfaces 5b as shown by arrows R in FIG. 5. The ring connectors 5 are thus placed against the Y-shaped beam portions or branches 3c′, where they can be attached for transport, as described above.

[0075] FIG. 6 provides details on a possible embodiment of said quick release interfaces 5a. Crossbeam 8 is preferably provided with a bracket 8a, which may compensate for different vertical positions (heights) of crossbeam 8 and longitudinal beams (not shown). Bracket 8a and ring connector 5 have alignable through-holes 8aa, 8ab, 5c, through which passes a cotter pin or a pin (bolt) 9 secured by a nut 10.

[0076] FIG. 7 shows a second step for pre-positioning of the rotors 3b during folding of the aircraft 1. The rotors 3b have been oriented (and secured, preferably) so that they point, with their respective blade axis, in the longitudinal direction x for those rotors 3b located on the longitudinal beams 7.1, 7.2, whereas the rotors 3b are oriented so that they point in the transverse direction y for those rotors 3b located on the crossbeam 8. Alternatively, the rotors could be dismounted prior to said second step.

[0077] Then, in a third step according to FIG. 8, the longitudinal beams 7.1, 7.2 are folded downwards, as shown by arrows R′. Reference numeral 7a denotes a (quick) release mechanism for the longitudinal beam 7.1 that has to be operated before rotation R′ can be performed. The same holds for longitudinal beam 7.2. Release mechanism 7a can be devised as shown in FIG. 6 for release mechanism 5a. For rotation, longitudinal beams 7.1, 7.2 are fixed to a respective point of rotation or pivot joint PR (shown only on one side) that is attached to the fuselage 2 by means of a support structure 7b. Thus, a corresponding pivot axis is parallel to the aircraft's longitudinal axis (cf. axes PA in FIG. 2). Reference numerals 7.1′, 7.2′ denote the longitudinal beams after rotation.

[0078] The other release mechanisms 5a shown in FIG. 8 can be those that were mentioned earlier in connection with FIGS. 4 and 6 (for releasing the ring connectors 5). Some of them, i.e., those located on the longitudinal beams 7.1, 7.2, can be re-used to fix the folded longitudinal beams 7.1′, 7.2′ to a landing gear 2″ located below fuselage 2 (and optional payload 2′). To this end, the landing gear 2″ can have suitable fixing structures (not shown). Landing gear 2″ (and the aforementioned release mechanisms 5a) define a maximum width MW of the folded aircraft 1 for transport purposes.

[0079] The aircraft 1 may comprise a resilient mechanism, e.g., a respective gas spring, devised to support a pivoting motion of said longitudinal beams 7.1, 7.2, preferably in the form of a detachable mechanism. This is not shown in the Figures.

[0080] FIG. 9 shows further structural details of the aircraft 1. Reference numeral 8b denotes a crossbeam mount which serves to securely attach crossbeam 8 to a main fuselage bulkhead 2a. Further shown are landing gear brackets 2a″ for attaching landing gear 2″ to fuselage 2 (or bulkhead 2a) and payload mounting brackets 2a′ for attaching payload 2′ to fuselage 2 (or bulkhead 2a or landing gear 2″). Reference numeral 100 denotes the ground.

[0081] FIG. 10 shows the next (fourth) step during folding of the aircraft 1, similar to the drawing in FIG. 7, but with the longitudinal beams already in their downwardly rotated positions (cf. FIG. 8). Crossbeam 8 is rotated according to arrow R″ into the longitudinal direction x to its new position denoted 8′. This can be achieved, depending on the nature of crossbeam mount 8b (FIG. 9), by releasing the crossbeam 8 and then rotating around a point of rotation PR′, which can be a fixed pivot joint. However, embodiments without such joint are possible and have been described further up. In particular, aircraft 1 may comprise a detachable crossbeam jig (not shown) that temporarily provides said pivot joint for rotation R″. Rotation R″ is around a pivot axis which is parallel to the aircraft's vertical axis (z).

[0082] At reference numeral 5a, release mechanisms on crossbeam 8 can be reused to provide interconnection between rotated crossbeam 8′ and (rotated) longitudinal beams 7.1′, 7.2′ for transport purposes. However, dedicated additional mechanisms (not shown) could be provided as well.

[0083] FIG. 11 comprises a detail from said last step, wherein electrical cables 11 are shown that pass along (or within) crossbeam 8 and then enter the fuselage (not shown) through mount 8a (cf. FIG. 9). Said cables can provide electrical energy to the rotors and/or signal connection with sensors or other equipment etc. (cf. FIG. 1). Cables 11 have sufficient (slack) length to avoid rupture and/or disconnection when rotating crossbeam 8 into its rotated position 8′. Reference numerals 11′ denote said cables after crossbeam rotation.

[0084] FIG. 12 shows the final folded configuration of aircraft 1, as explained in detail above. On the left-hand side, aircraft 1 is shown in a plan view from above. On the right-hand side, aircraft 1 is shown in a frontal view. Advantageously, maximum width and length are such that the folded aircraft 1 can fit into a standard 40 ft container for shipping.