Patent Publication Number: US-2022227485-A1

Title: Unmanned aerial vehicle folding landing gear

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Application Ser. No. 62/318,918 filed on Apr. 6, 2016, U.S. Pat. No. 10,266,245 filed on Sep. 15, 2016, U.S. Pat. No. 10,994,833 filed on Aug. 17, 2018, and is a continuation-in-part to copending U.S. patent application Ser. No. 17/012,513 filed on Sep. 4, 2020, the contents of each of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to aerial vehicles, and more particularly to a folding landing gear for a heavy-lift UAV. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     An unmanned aerial vehicle (UAV) is a heavier-than-air flying machine that does not carry a human operator. UAV&#39;s are utilized for many different military and civilian applications such as reconnaissance, surveillance, area mapping, and/or photography, for example. 
     Traditionally, the use and implementation of hobby grade vertical takeoff and landing UAV&#39;s was severely limited by the relatively low lifting capacity of the same. However, recent advancements have seen the introduction of small size UAV engines which can carry payloads exceeding 30-50 pounds each, and for prolonged periods of time. As such, UAV&#39;s are now being contemplated for use in new industries, and for performing tasks never before possible. In this regard, a heavy-lift UAV is one that is capable of performing sustained flight with payloads greater than 25 pounds. Several examples include equipping a heavy-lift UAV with an agricultural spraying module, LIDAR remote sensing equipment, or a payload basket for transporting goods from one location to another. 
     Although such applications are promising, the current design and construction of UAV landing gear systems is not conducive for heavy-lift applications that require compact storage between flights. This is because such systems fold the gear outward (e.g., away from the drone body) and occupy a stored footprint that is often 2-3 times the footprint of the drone body itself. Moreover, such systems typically require a separate mounting bracket and often comprise a complex network of interconnected components wherein a single failure point in one component jeopardizes the ability of the remaining landing gear legs from functioning properly. 
     The present invention directed to a heavy-lift UAV frame mounted landing gear system differs from the conventional art in a number of aspects. The manner by which will become more apparent in the description which follows, particularly when read in conjunction with the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a heavy-lift UAV frame. One embodiment of the present invention can include a central frame portion having a symmetrical shape and forming a pocket area for receiving an avionics package. A top and bottom plate can be secured to the central frame portion and can include four corner members extending diagonally outward therefrom. 
     Another embodiment of the present invention can include a plurality of boom hinges that are interposed between each of the corner members and an elongated boom arm. Each of the boom hinges can be pivotally connected to the boom arms and can transition the boom arms between an extended position for flight and a retracted position for storage and transport. Each boom arm and boom hinge can include a complementary dimension to one side of the central frame portion so as to arrange each boom arm parallel thereto when in the retracted position. 
     Another embodiment of the present invention can include a plurality of elongated landing gear legs that are each connected to the bottom end of the main body by a folding landing gear hinge. Each of the landing gear legs can independently transform between a ready for flight position and a storage position. In the ready for flight position, the gear legs can be positioned diagonally away from each corner of the main body, and in the storage position each of the gear legs can be positioned beneath the main body. 
     This summary is provided merely to introduce certain concepts and not to identify key or essential features of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Presently preferred embodiments are shown in the drawings. It should be appreciated, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
         FIG. 1A  is a perspective view of the top side of the central frame portion that is useful for understanding the inventive concepts disclosed herein. 
         FIG. 1B  is a perspective view of the bottom side of the central frame portion, in accordance with one embodiment of the invention. 
         FIG. 2  is a perspective view of a boom arm of the heavy-lift UAV frame, in accordance with one embodiment of the invention. 
         FIG. 3A  is a perspective view of a boom hinge of the heavy-lift UAV frame in the open position, in accordance with one embodiment of the invention. 
         FIG. 3B  is a perspective view of a boom hinge of the heavy-lift UAV frame in the closed position, in accordance with one embodiment of the invention. 
         FIG. 4A  is an exploded parts view of the heavy-lift UAV frame, in accordance with one embodiment of the invention. 
         FIG. 4B  is a perspective view of the heavy-lift UAV frame in the retracted position, in accordance with one embodiment of the invention. 
         FIG. 4C  is a perspective view of the heavy-lift UAV frame in the extended position, in accordance with one embodiment of the invention. 
         FIG. 5  is a perspective view of a landing gear leg of the heavy-lift UAV frame, in accordance with one embodiment of the invention. 
         FIG. 6  is an exploded parts view of a landing gear hinge, in accordance with one embodiment of the invention. 
         FIG. 7A  is a perspective view of a landing gear hinge of the heavy-lift UAV frame in the ready for flight position, in accordance with one embodiment of the invention. 
         FIG. 7B  is a perspective view of a landing gear hinge of the heavy-lift UAV frame in the storage position, in accordance with one embodiment of the invention. 
         FIG. 8A  is a perspective view of the heavy-lift UAV frame with the landing gear in the ready for flight position, in accordance with one embodiment of the invention. 
         FIG. 8B  is a perspective view of the heavy-lift UAV frame with the landing gear in the storage position, in accordance with one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the description in conjunction with the drawings. As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the inventive arrangements in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention. 
     Identical reference numerals are used for like elements of the invention or elements of like function. For the sake of clarity, only those reference numerals are shown in the individual figures which are necessary for the description of the respective figure. For purposes of this description, the terms “upper,” “bottom,” “right,” “left,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIG. 1A . 
     As described throughout this document, the term “complementary dimension,” shall be used to describe a situation wherein an object includes a size that is identical to, or substantially identical to the size of another component, in terms of length, and/or width, and/or height, for example. 
     As described throughout this document, a “small UAV” is described as any unmanned aerial vehicle having a total footprint of less than 6 feet in diameter, and a total unit weight of less than 60 pounds. 
     As described herein, the term “removably secured,” “removably engaged” and derivatives thereof shall be used to describe a situation wherein two or more objects are joined together in a non-permanent manner so as to allow the same objects to be repeatedly joined and separated. This can be accomplished through the use of any number of commercially available connectors such as opposing strips of hook and loop material (i.e. Velcro®), magnetic elements, and compression fittings such as hooks, snaps and buttons, for example. 
     As described herein, the term “pivotally connected,” “rotatably secured” and all derivatives shall be used interchangeably to describe a situation wherein two or more objects are joined together in a manner that allows one or both of the objects to pivot and/or rotate about or in relation to the other object along one or more axes. 
       FIGS. 1A-8B  illustrate various embodiments of heavy lift UAV system  10  that is useful for understanding the inventive concepts disclosed herein. As shown, the device  10  can include, essentially a main body  11  having a plurality of booms  21 , and a plurality of landing gear legs  50  that are pivotally secured thereon. 
     As shown best in  FIGS. 1A and 1B , the main body  11  can include a generally square shaped central body portion  12  for receiving and storing any type of avionics. As such, the central body portion can include a recessed bottom wall  12   a  and a plurality of raised side walls  12   b ,  12   c ,  12   d , and  12   e . By encircling the delicate avionics within the rigid frame members of the central body portion  12 , the main body  11  advantageously forms a pocket area that can protect and shelter the delicate components from being directly impacted by another object in the event of a crash. 
     The main body can also include a top plate  13  having edges  13   b ,  13   c ,  13   d  and  13   e , and a bottom plate  14  having edges  14   b ,  14   c ,  14   d  and  14   e . Top and bottom edges  13   b - 13   e  and  14   b - 14   e  being arranged so as to extend outward from the central walls  12   b - 12   e , respectively. As shown, each of the top and bottom plates can also include corner members  15  and  16 , respectively, which extend diagonally outward from the central portion  12 . 
     The distal ends of the top and bottom corner members can include a plurality of apertures  15   a  and  16   a , respectively, that are aligned vertically so as to receive the below described boom hinges  30  along each corner. Additionally, the bottom plate  16  can include a plurality of apertures  16   b  so as to receive the below described gear hinges  60  along each corner. 
     In the preferred embodiment, the main body  11  can be constructed from a lightweight and sturdy material such as aluminum, for example, however other construction materials such as plastic, carbon fiber and other forms of composite materials are also contemplated. The central body portion  12 , the top plate  13  and the bottom plate  14  can be constructed from identical or different materials and can be secured together in any number of commercially known manners. 
       FIG. 2  illustrates one embodiment of a boom arm  20  which can be pivotally secured onto each corner of the main body via the below described boom hinge  30 . As shown, the boom can include an arm member  21  that is preferably in the shape of a hollow square tube, having a first end  21   a , a second end  21   b  a top surface  21   c  a bottom surface  21   d  and a pair of side surfaces  21   e  and  21   f . The second end of the boom arm  21   b  can function to receive and securely position a pair of electric engines  5  along both the top and bottom surfaces thereof. When such engines are installed, the engine control cables (not illustrated) can be routed through the hollow portion of the arm and hinge for connection to an avionics package located on the main body  11 . The first end of the boom arm  21   a  can include a horizontal channel  22  for receiving a locking shaft of the boom hinge. 
       FIGS. 3A and 3B  illustrate one embodiment of a boom hinge  30 . As shown, the hinge  30  can include a first body section  31  having an open first end that leads to a hollow interior space  31   a  for receiving the first end  21   a  of a boom arm  20 . A pair of boom clamping screws  32   a  are provided so as to allow a user to tighten the hinge onto a boom arm that is positioned within the hollow interior space. Likewise, an elongated safety screw  32   b  is removably positioned through the horizontal channel  22  of the boom arm secured within the hollow interior space to prevent separation of the arm and hinge. 
     The boom hinge can also include a second body section  33  having a pair of generally U-shaped protrusions  34  each having apertures  34   a  extending therethrough. Apertures  34   a  including a shape, size and orientation that are complementary to the shape, size and orientation of apertures  15   a  and  16   a , so as to receive mounting hardware  34   b  therethrough. 
     As shown best at  FIG. 3B , a pivoting pin  35  can be positioned between the first and second body sections  31  and  33 , respectively, to permit both sections to pivot (see arrow a), relative to the other. In one embodiment, a spring-loaded sliding locking pin  36  can be positioned along the first body member. The lock pin can include an opening  36   a  for selectively engaging a retainment pin  37  that is positioned on the second body section  33 . When the lock pin  36  is secured onto the retainment pin  37 , the hinge is immobilized. In this regard, the hinge can transition from the open position shown at  FIG. 3A  and the folded position shown at  FIG. 3B  via movement (see arrow b) of the lock pin  36 . Moreover, it is noted that movement of the hinge is perpendicular to the lifting force applied by the boom arms onto the main body. As such, the boom hinge has no excessive play/vertical slop, and therefore reduces or eliminates problematic vibrations of the boom arms noted above. 
     As shown in  FIGS. 4A-4C , the heavy-lift UAV frame  10  can include four boom arms  20  which can be pivotally secured onto the corner of the main body via the above-described boom hinges. As shown best in  FIG. 4A , the first end of each boom arm can be positioned inside the first end of the boom hinge  31 , and the second end of each boom hinge  33  can be positioned between the corner members  15  and  16  (See arrow c). At this time, apertures  34   a ,  15   a  and  16   a  will be aligned vertically, and can function to receive mounting hardware  34   a , such as the illustrated screws, for example, to prevent inadvertent separation of the hinge and frame. When fully installed, the hinge  30  can pivot each boom arm horizontally between a fully extended position and a fully retracted position. 
     As shown in  FIG. 4B , each hinge  30  and attached boom arm  20  can include a length/assembled dimension (e.g., distance between elements  33  and  21   b ) that is complementary to the length of one side of the central body walls  12   b - 12   e  and/or edges  13   b - 13   e  and  14   b - 14   e . This dimension, combined with the symmetrical square shape of the central body portion, advantageously allows the assembled frame  10  to transition to a fully retracted position, wherein each boom arm  20  can be pivoted until it is located parallel with one side of the central body portion  12   b - 12   e  and/or edges  13   b - 13   e  and  14   b - 14   e , respectively. When so positioned, the corner members  15  and  16  will be the outermost components of the frame. Such a design advantageously allows the sturdy corner members to protect the boom arms against impacts with foreign objects when the frame member is retracted for storage and/or transport. 
       FIG. 4C  illustrates one embodiment of the frame  10  in the fully extended position, wherein each of the boom arms are extending outward from the corner of the main body and are locked in place by the locking pin  36  and retainment pin  37  of the boom hinge  30 . As each of the boom hinge and arm combination includes a length that is complementary to the length of each of the side walls of the central body portion  12 , the frame remains completely symmetrical from each side when fully extended. This symmetrical design combined with the absence of slop within the boom hinge advantageously eliminates much of the vibrations that are experienced by other known devices, as each of the engines  5  are positioned at a uniform distance from each other and the payload/avionics being carried by the central portion of the frame  12 . 
       FIG. 5  illustrates one embodiment of an individual landing gear leg  50  which can be pivotally secured onto each corner of the main body via the below described landing gear hinge  60 . As shown, the leg can include an elongated member  51  that is preferably in the shape of a hollow round tube, having a first end  51   a , and a second end  51   b . In one embodiment, the first end of the gear leg  51   a  can include a horizontal channel  52  for receiving a locking screw of the gear hinge. In various embodiments, the second end of the leg  51   b  can function to receive a surface contact plate as the illustrated cap  53  which can be constructed from or can include a non-skid material such as rubber, for example. 
     Of course, other embodiments are contemplated wherein different types of surface contact plates are utilized. Several nonlimiting examples include the use of wheels for permitting the drone to taxi, floats for permitting the drone to land on water, and/or an elongated generally flat plate which can be hingedly or fixedly connected along the distal end of each leg  51   b  for use in winter conditions to permit the drone to land and takeoff from snow without sinking into the same. 
     Although dimensions are not critical, in the preferred embodiment, the main body  11  can preferably include a diagonal length between each corner section of approximately 30 inches. Likewise, each boom  20  and hinge  30  combination can preferably include a length of approximately 24 inches from end to end. Such dimensions being suitable for allowing each boom to support two engines having 32-inch propellers giving the frame a lifting capacity of over 1,000 pounds. Of course, other sizes are also contemplated. 
       FIGS. 6, 7A and 7B  illustrate one embodiment of a landing gear hinge  60 . As shown, the gear hinge  60  can include a first body section  61  having an open first end that leads to a hollow interior space  61   a  for receiving the first end  51   a  of a landing gear leg  50 . The gear hinge can also include a semi-circular shaped protrusion  62  extending opposite to the open first end for positioning within the channel  75  of the second body section  71 . 
     In one embodiment, a central aperture  63  can be positioned through the protrusion to engage the below described pivot pin  76 . Likewise, a plurality of positional grooves  64   a  and  64   b  can be located along the outer edges of the protrusion for engagement by the locking pin  77 . 
     In one embodiment, a pair of leg clamping screws  65   a  are provided so as to allow a user to tighten the hinge onto a leg that is positioned within the hollow interior space  61   a , and an elongated safety screw  65   b  is removably positioned through the horizontal channel  52  of the gear leg secured within the hollow interior space to prevent separation of the leg and hinge. 
     The gear hinge can also include a second body section  71  having a top mounting surface  72  with a plurality of apertures  72   a  extending therethrough. Apertures  72   a  including a shape, size and orientation that is complementary to the shape, size and orientation of apertures  16   b  located along the corners  16  of the bottom plate  14 , so as to receive mounting hardware  72   b  therethrough. 
     In one embodiment, a pair of arms  73  and  74  can extend outward in a direction opposite to the top mounting surface and can form a channel  75  for receiving the protrusion  62  of the first body section. Each of the arms can include apertures  73   a / 73   b  and  74   a / 74   b  which can be aligned such that  73   a / 74   a  and  73   b / 74   b  are in a linear relationship, respectively. 
     As shown, a pivoting pin  76  can be positioned through apertures  73   a ,  63  and  74   a  when the first and second body sections are connected in order to permit both sections to pivot (see arrow d), relative to the other. 
     In one embodiment, a locking pin  77  can be positioned through the second set of apertures  73   b  and  74   b  to selectively engage the positional groves  64   a  and  64   b  of the first body section, to orient the gear hinge in either the flight-ready or storage position. 
     In the illustrated embodiment, the locking pin  77  can include a first end  77   a , a middle section  77   b , a second end  77   c  and a compression spring  77   d . In the preferred embodiment, the middle portion  77   b  can include a diameter that is less than the diameter of the first and second ends  77   a  and  77   c , so as to result in the second end having a shoulder section  77   c   1  extending 90 degrees radially and perpendicularly to the outer surface of the middle portion. 
     In the assembled configuration, the compression spring  77   d  can be positioned against a ledge within the aperture  74   b , so as to position the second end  77   c  of the pin within the channel area  75  in order to engage one of the groves  64   a  or  64   b  in the resting position. Such a feature working to automatically lock the gear hinge in either the flight ready or storage position unless acted on by a user. 
     In order to switch between the flight ready and storage positions, a user can impart a pushing force against the first end  77   a  of the pin which will cause the spring  77   d  to compress and allow the second end  77   c  to disengage the grove  64   a  or  64   b  and move into the second aperture  74   b . At this time, the narrow middle portion  74   c  of the pin will be located within the channel  75  thus permitting rotation of the first and second body sections  61  and  71  to transition between the flight ready position and the storage position. 
     In the preferred embodiment, when the locking pin  77  is engaged with grove  64   a , the hinge  60  will be in the flight-ready position shown at  FIGS. 7A and 8A , and when the locking pin is engaged with grove  64   b , the hinge will be in the storage position shown at  FIGS. 7B and 8B . 
     In this regard, it is noted that grove  64   a  will preferably include a shape and size that is complementary to the shape and size of the shoulder portion  77   c   1  of the locking pin so as to prevent or minimize play/movement of the hinge and landing gear leg  50  when the system is in the flight ready position. Conversely, grove  64   b  will preferably include a shape and size that is slightly larger than the shape and size of the shoulder portion  77   c   1  of the locking pin, so as to allow limited movement of the hinge and landing gear arm when the system is in the storage position. 
     This limited movement will permit the landing gear legs to cross one another as the gear folds for storage. This movement ideally will be suitable for providing movement of the hinge of between about 2 and 4 degrees; however other embodiments allowing for different movement amounts and angles are also contemplated. 
     As shown best in  FIG. 8A , the first end of each leg  51  can be positioned inside the first end of the gear hinge  61 , and the second end of each gear hinge  71  can be positioned along one corner  16  of the bottom plate  14  (See arrow e). At this time, mounting apertures  72   a  will be aligned with plate apertures  16   b , and so as to receive mounting hardware  72   b , such as the illustrated screws, for example, to secure each landing gear hinge and leg onto the bottom of the frame. When fully installed, the gear hinges  60  can pivot each leg between the fully extended and ready for flight position and the storage position. 
     In the flight ready position, each of the legs will preferably be oriented so as to extend outward from the respective sides of the main body plate  14  at an angle θ of [INSERT] degrees. Such a feature ensuring the landing gear does not affect a payload suspended beneath the bottom of the drone during flight. Of course, other embodiments are contemplated wherein the legs are positioned at a different angle. 
     As shown in  FIG. 8B , wherein the landing gear is in the storage position, each gear hinge  60  and attached leg  50  can include a length/assembled dimension (e.g., distance between elements  72  and  53 ) that is complementary to the length of one side of the main body  14  between edges  16  so as to be positioned between sides  14   c  and  14   e  at a location beneath the central body walls  12   b  and  12   d . These dimensions allow the landing gear to be completely positioned beneath the frame in the storage position such that the corner members  15  and  16  will be the outermost components of the entire assembly. Such a design advantageously allows the sturdy corner members to protect the landing gear legs against impacts with foreign objects when the UAV boom arms and landing gear is retracted for storage and/or transport. 
     Additionally, because the landing gear hinges  60  are positioned angularly θ away from the corners of the main body in the flight ready position, the landing gear legs will be positioned at an inverse angle that is toward the center of the frame in the folded position. As such, the legs  50  will necessarily cross one another along the midway portion of the frame  14 . For this reason, the limited movement described above with regard to grove  64   b  permits one leg on each side to be fully perpendicular relative to the main body, and the other leg on each side to be slightly angular via the allowed 2-4 degrees. Such a feature permits either leg to be positioned above or below the other in the folded and storage position while remaining locked and unable to fully extend to the flight ready position without a user engaging the locking pin  77 . 
     Although dimensions are not critical, in the preferred embodiment, the main body  11  can preferably include a diagonal length between each corner section of approximately 30 inches. Likewise, each leg  50  and gear hinge  60  combination can preferably include a length of approximately [INSERT] inches from end to end. Such dimensions being suitable for allowing each boom to support two engines having 32-inch propellers giving the frame a lifting capacity of over 1,000 pounds, while permitting the landing gear to transition between the flight ready and storage positions shown. Of course, other sizes are also contemplated. 
     As described herein, one or more elements of the heavy-lift UAV frame  10  can be secured together utilizing any number of known attachment means such as, for example, screws, glue, compression fittings and welds, among others. Moreover, although the above embodiments have been described as including separate individual elements, the inventive concepts disclosed herein are not so limiting. To this end, one of skill in the art will recognize that one or more individually identified elements may be formed together as one or more continuous elements, either through manufacturing processes, such as welding, casting, or molding, or through the use of a singular piece of material milled or machined with the aforementioned components forming identifiable sections thereof. 
     As to a further description of the manner and use of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Likewise, the terms “consisting” shall be used to describe only those components identified. In each instance where a device comprises certain elements, it will inherently consist of each of those identified elements as well. 
     The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.