UAV WITH FRANGIBLE AIRFRAME STRUCTURES

• US 20190329857A1
• Filed: 04/27/2018
• Published: 10/31/2019
• Est. Priority Date: 04/27/2018
• Status: Active Grant

• Current Assignee: Wing Aviation LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Benson, Stephen, Nielsen, Christian, Woodworth, Adam
• Granted Patent: US 10,894,593 B2
• Time in Patent Office: Days
• CPC Class Codes: B64C 1/061 Frames
• CPC Class Codes: B64C 1/26 Attaching the wing or tail units or stabilising surfaces
• CPC Class Codes: B64C 29/0025 the propellers being fixed relative to the fuselage
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64U 10/25 Fixed-wing aircraft VTOL aircraft B64U10/20
• CPC Class Codes: B64U 20/30 for safety, e.g. with frangible components rotor guards B64U30/299
• CPC Class Codes: B64U 30/10 Wings
• CPC Class Codes: B64U 30/20 Rotors; Rotor supports
• CPC Class Codes: B64U 50/13 using external fans or propellers
• CPC Class Codes: F16B 11/006 by gluing gluing of plastics material B29C65/48
• CPC Class Codes: F16B 2/065 using screw-thread elements F16B2/08 - F16B2/12 take precedence
• CPC Class Codes: F16B 33/006 Non-metallic fasteners using screw-thread
• CPC Class Codes: F16B 7/0493 forming a crossed-over connection

Abstract

A mechanical joiner for an airframe includes a joiner core and first and second caps. The joiner core has a first side with a first cradle shaped to hold a first structural member and a second side with a second cradle shaped to hold a second structural member. The first cap is shaped to mate to the first side and clamp the first structural member into the first cradle. The joiner core includes a first hole for a first mechanical fastener to extend through and across the first cradle and secure the first cap to the joiner core. The second cap is shaped to mate to the second side and clamp the first structural member into the second cradle. The second cap includes second holes for second mechanical fasteners, distinct from the first mechanical fastener, to secure the second cap to the joiner core.

Claims

1. A mechanical joiner for an airframe, comprising:

a joiner core having a first side with a first cradle shaped to hold a first structural member and a second side with a second cradle shaped to hold a second structural member;

a first cap shaped to mate to the first side of the joiner core and clamp the first structural member into the first cradle, wherein the joiner core includes a first hole for a first mechanical fastener to extend through and across the first cradle to secure the first cap to the joiner core; and

a second cap shaped to mate to the second side of the joiner core and clamp the first structural member into the second cradle, wherein the second cap includes second holes for second mechanical fasteners, distinct from the first mechanical fastener, to secure the second cap to the joiner core.

2. The mechanical joiner of claim 1, wherein the first mechanical fastener does not extend through the second cap.

3. The mechanical joiner of claim 2, wherein a head of the first mechanical fastener is recessed into the second cradle of the joiner core so as not to physically interfere with seating the second structural member into the second cradle.

4. The mechanical joiner of claim 1, wherein the second mechanical fasteners that secure the second cap each have less shear or tensile strength than the first mechanical fastener that passes through and across the first cradle.

5. The mechanical joiner of claim 4, wherein the second mechanical fasteners comprise four plastic screws that thread into the second side of the joiner core.

6. The mechanical joiner of claim 4, wherein the first mechanical fastener comprises a metal mechanical fastener and the metal mechanical fastener comprises a nut and a bolt.

7. The mechanical joiner of claim 1, further comprising:

an anti-rotation pin that extends through the second cap into the second structural member to prevent rotation of the second structural member within the second cradle.

8. The mechanical joiner of claim 7, wherein the anti-rotation pin comprises a nylon screw.

9. The mechanical joiner of claim 7, further comprising:

a layer of adhesive applied to an inside surface of the second cap that conforms with and mates to the second structural member to adhere the second structural member to the second cap.

10. The mechanical joiner of claim 1, wherein the joiner core, the first cap, and the second cap are fabricated of glass filled nylon and the first structural member and the second structural member each comprise a hollow tubular rod.

11. An unmanned aerial vehicle (UAV), comprising:

a wing assembly including a wing spar;

a boom assembly including a boom and a plurality of motor mounts secured to the boom; and

a spar-boom joiner for mechanically securing the wing spar to the boom, the spar-boom joiner including;

a joiner core having a first side with a spar cradle shaped to hold the wing spar and a second side with a boom cradle shaped to hold the boom;

a spar cap shaped to mate to the first side of the joiner core and clamp the wing spar into the spar cradle, wherein a spar fastener extends through the wing spar and secures the spar cap to the joiner core; and

a boom cap shaped to mate to the second side of the joiner core and clamp the boom into the boom cradle, wherein second mechanical fasteners, distinct from the spar fastener, secure the boom cap to the joiner core.

12. The UAV of claim 11, wherein the spar fastener is a mechanical fastener that does not extend through the boom cap.

13. The UAV of claim 12, wherein a head of the spar fastener is recessed into the boom cradle of the joiner core so as not to physically interfere with seating the boom into the boom cradle.

14. The UAV of claim 11, wherein the second mechanical fasteners each have less shear or tensile strength than the spar fastener.

15. The UAV of claim 14, wherein the second mechanical fasteners comprise four plastic screws that thread into the second side of the joiner core.

16. The UAV of claim 14, wherein the spar fastener comprises a metal mechanical fastener and the metal mechanical fastener comprises a nut and a bolt.

17. The UAV of claim 11, further comprising:

an anti-rotation pin extending through the boom cap into the boom to prevent rotation of the boom within the boom cradle.

18. The UAV of claim 17, wherein the anti-rotation pin comprises a nylon screw.

19. The UAV of claim 17, further comprising:

a layer of adhesive applied to an inside surface of the boom cap that conforms with and mates to the boom to adhere the boom to the boom cap.

20. The UAV of claim 11, wherein the joiner core, the spar cap, and the boom cap are fabricated of glass filled nylon and the wing spar and the boom each comprise a hollow tubular rod.

21. The UAV of claim 11, further comprising a modular fuselage secured to the wing spar, the modular fuselage including:

a first section secured to the wing spar with a second joiner that clamps onto the wing spar, wherein the second joiner is clamped with first plastic screws selected to fail upon a collision impact of the modular fuselage; and

one or more other sections connected to the first section, wherein the one or more other sections are secured to the first section at connection points secured together with second plastic screws selected to fail upon the collision impact of the modular fuselage.