Abstract:
A multi-rotor UAV having a pull pin mechanism that engages and disengages the rotor arms from a deployed, in-flight position to a storage or transport configuration, thus making the UAV more portable and capable of carrying larger payloads with the flexibility of folding into a smaller configuration or profile for transport, such as in a backpack. The device includes a rotor arm utilization of a pull pin mechanism to lock and unlock the position of the arms, and a proprietary frame.

Description:
RELATED APPLICATION(S) 
     This application is continuation-in-part of and related to U.S. Provisional Patent Application Ser. No. 61/985,319 filed Apr. 28, 2014, entitled COLLAPSIBLE MULTI-ROTOR UAV, which is incorporated herein by reference in its entirety, and claims any and all benefits to which it is entitled therefrom. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a proprietary design for a multi-rotor, unmanned aerial vehicle (hereafter “UAV”), and more particularly to a collapsible, quad-rotor UAV. 
     BACKGROUND OF THE INVENTION 
     An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot aboard. Its flight is controlled either autonomously by onboard computers or by the remote control of a pilot on the ground or in another vehicle. The typical launch and recovery method of an unmanned aircraft is by the function of an automatic system or an external operator on the ground. In general, UAVs are simple, remotely piloted aircraft, but autonomous control is increasingly being employed. 
     Most designs for multi-rotor UAVs are rigid. The ones that incorporate a compacting or a “fold” configuration usually utilize hinges in order to produce a collapsible design for the prototypes. Hinge mechanisms that rotate motor arms in both vertical and horizontal axes of the UAV have dominated the collapsible UAV design pool. These designs, although successfully reducing the size of the UAVs, are limited due to lack of symmetry and the length of various extremities. Other methods for decreasing the size of a quad rotor UAV in transit include detachable quick release components. Once the extremities of the quad are removed, the size of the case required to protect and transport the UAV unit also decreases. However, these designs which usually utilize small screws and bolts to hold various parts together, presenting a disadvantage in the field when attempting to deploy a UAV unit. Hardware required for assembly gets lost and the time required for deployment can cause delays. 
     The present invention utilizes design symmetry and a pull pin mechanism to reduce both the space required to transport and the time it takes to deploy a multi-rotor UAV. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a representative isometric view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration. 
         FIG. 1B  is a representative top view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration. 
         FIG. 1C  is a representative front view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration. 
         FIG. 1D  is a representative side view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration. 
         FIG. 1E  is another representative isometric view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration. 
         FIG. 2A  is a representative isometric view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration. 
         FIG. 2B  is a representative side view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration. 
         FIG. 2C  is a representative top view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration. 
         FIG. 2D  is a representative front view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration. 
         FIG. 2E  is a representative lower view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration. 
         FIG. 3A  is a representative partial view of an embodiment of the arm connection of the collapsible multi-rotor quad-copter UAV of the present invention in an assembled configuration. 
         FIG. 3B  is a representative exploded partial view of an embodiment of the arm connection of the collapsible multi-rotor quad-copter UAV of the present invention. 
         FIG. 3C  is a representative view of an embodiment of an arm of the collapsible multi-rotor quad-copter UAV of the present invention in an assembled configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The description that follows is presented to enable one skilled in the art to make and use the present invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principals discussed below may be applied to other embodiments and applications without departing from the scope and spirit of the invention. Therefore, the invention is not intended to be limited to the embodiments disclosed, but the invention is to be given the largest possible scope which is consistent with the principals and features described herein. 
     It will be understood that in the event parts of different embodiments have similar functions or uses, they may have been given similar or identical reference numerals and descriptions. It will be understood that such duplication of reference numerals is intended solely for efficiency and ease of understanding the present invention, and are not to be construed as limiting in any way, or as implying that the various embodiments themselves are identical. 
     The present invention is unique design for a multi-rotor UAV to reduce the amount of time needed to assemble and deploy a UAV in the field as well as provide a way to compact the UAV into a manageable size for transportation. 
     The present invention reflects an increase in the size of the body frame and a decrease in the length of motor arms compared to prior models. By reducing the size of the motor arms they can fold symmetrically against the sides of the body. Once in this transport position, a pull pin mechanism locks the motor arms in place. Upon release of the pull pin mechanism, the arms are free to move in the horizontal plane. When fully extended, the pull pin mechanism will securely lock restricting the movement of the motor arms in a deployed position. 
     Each motor arm pivots around a single bind screw that allows it to move in the horizontal plane. Inserted between the bind screw and the carbon fiber body plate are neoprene washers used to dampen the effects of vibration caused by the motors and allow for the ease of movement between deployed and stored positions. Each motor arm is designed with a grated pattern to allow for a lighter weight and to allow the arm to absorb the force of impact. 
     The body is designed to allow the arms to fold up against the sides neatly. The design uses carbon fiber for its strength and lightweight properties. 
       FIG. 1A  is a representative isometric view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration.  FIG. 1B  is a representative top view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration.  FIG. 1C  is a representative front view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration.  FIG. 1D  is a representative side view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration.  FIG. 1E  is another representative isometric view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a flight configuration. 
     UAV  100  consists of a top plate  102  made of carbon fiber or other rigid, durable material, a bottom plate  104  made of similar material, four (4) rotating rotor arms  106  made of molded urethane or similar and four (4) corresponding propellers or rotors  108 . Binding screw mechanism  110  sandwiched between the top plate  102  and the bottom plate  104  and provides an axis for rotation of the rotor arms  106 . A spring locking pull pin  114 , operated manually or via small motors controlled remotely, lock the arms  106  into either the deployed position such as shown in  FIGS. 1A-E  or the collapsed position such as shown in  FIGS. 2A-E . 
     Molded urethane polymer protective cover  116  protects the flight electronics, provides impact protection and resistance to the elements. support plate  118  made of carbon fiber or other suitable material supports a battery or battery pack. Landing gear  120  made of molded urethane polymer or other suitable material is either permanently mounted to the bottom plate  104 , or is secured to the UAV with thumb nuts or similar manually operated coupling. Having removable landing gear  120 , the UAV  100  of the present invention can be disassembled and transported or stored efficiently. 
     A camera mount  122  made of carbon fiber or other rigid, durable material is particularly adapted for downward facing cameras or other sensors, and placing additional camera or sensor mounts on the top of the UAV or on any or all of the sides would be within the scope and purview of the present invention. 
       FIG. 2A  is a representative isometric view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration.  FIG. 2B  is a representative side view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration.  FIG. 2C  is a representative top view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration.  FIG. 2D  is a representative front view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration.  FIG. 2E  is a representative lower view of an embodiment of the collapsible multi-rotor quad-copter UAV of the present invention in a compacted configuration. 
       FIG. 3A  is a representative partial view of an embodiment of the arm connection of the collapsible multi-rotor quad-copter UAV of the present invention in an assembled configuration.  FIG. 3B  is a representative exploded partial view of an embodiment of the arm connection of the collapsible multi-rotor quad-copter UAV of the present invention.  FIG. 3C  is a representative view of an embodiment of an arm of the collapsible multi-rotor quad-copter UAV of the present invention in an assembled configuration. 
     Rotor arms  106  have a proximal end  126  and a distal end  128 . Binding screw mechanism  110  engages rotor arm  106  at axis of rotation point  132 . At the distal end  128  of each rotor arm  106 , small, brushless electric motors  134  are mounted upon the upper surface  136  of each rotor arm  106  with small machine screws to operate the propellers  108  of the UAV  100  of the present invention. 
     Binding post mechanism  110  comprises internally threaded binding post  140 , first and second small neoprene rubber vibration dampening washers  142 , first and second large neoprene rubber vibration dampening washers  144 , and binding screw  146 . While the rotor arm  106  is sandwiched between large washers  144 , the top plate  102  and bottom plate  104  are sandwiched between small washers  142  and large washers  144 . 
     Internally and externally threaded tab nut  150  passes through bottom plate  104 . Hex nut  152  threads onto the tab nut  150  secured to bottom plate  104 . Pull pin  154  has a lever tip  156  and internal spring (not shown) contained within a central, externally threaded portion  158 . Plunger tip  160  extends through tab nut  150  into one of 2 positioning openings in the arm  106  such that upon manual activation of the lever tip  156  in the direction indicated A, plunger tip  160  retracts inside the central portion  158  and permits rotor arms  106  to swing freely between the deployed, flight position shown in  FIGS. 1A-1E  and the travel, compact configuration shown in  FIGS. 2A-E . Then, when the lever tip  156  is released, the plunger tip  160  advances into either one of the positioning arm holes  151  located on the distal end  126  of the rotor am  106 . 
     As mentioned above, top plate  102 , bottom plate  104 , battery support plate  118  and camera mount  116  are made of carbon fiber twill plate or other suitable, rigid material. Rotor arms  106 , landing gear  120  and electronics cover  116  can be made of molded urethane or similar polymer material, while the GPS mounting spacer and camera plate spacer can be made of 3D printed ABS plastic. Neoprene rubber sheeting can be used for forming the large vibration dampening washers  144  or small washers  142 , as well as a electronics seal between the cover  116  and top plate  102 . Plexiglass or similar plastic can be used for windows such as where transparency is important. Aluminum bind posts and screws are also used. 
     The UAV  100  uses a standard lithium polymer battery which are available or can be custom fabricated in various shapes and sizes. In a preferred embodiment, the battery is secured between the battery support plate  118  and the lower plate  104  and held in place by a portion of hook and loop material cinch strap that circles the battery and plate  118 . 
     Under the electronics cover  116 , the UAV  100  houses the flight electronics. Some of the electronic components are commercially purchased, but all can be custom configured and programmed. The flight electronics of the UAV  100  of the present invention utilize a standard APM 2.5.2 control board as its main flight computer. Coupled to the APM 2.5.2 board are the following components:
         A GPS module is utilized for providing accurate location and tracking data;   An air telemetry module provides communication with a ground computer while the UAV  100  is in flight; and   A radio receiver for radio control communication between the UAV  100  and a ground or other user is also part of the flight electronics.
 
A main power distribution board with combined ESC wiring harness provides a direct power and control connection to each of the 4 small rotor motors  134 . Each of the motors  134  is rated at about 800 KV, or more or less. LED strips for orientation lighting are mounted underneath the arms, adjacent the landing gear and may also be attached to the top or sides of the UAV 100 , as desired.
       

     Each rotor arm  106  is sandwiched between the top carbon fiber plate  102  and bottom carbon fiber plate  104  by the binding screw mechanism, and is isolated from vibration with large neoprene washer inserts  144  and small washers  142 . The spring locking pin mechanism  114  is threaded into and mechanically secured to the bottom carbon fiber plate  104  with a flat tab nut  150  that does not impede the rotation of the arm  106 . The arm  106  is “locked” when the spring pin  114  is extended and the plunger tip  160  is held by the force of the internal spring. The arm  106  is “unlocked” when the spring pin  114  is retracted. The central hole  132  located at the proximal end  126  of the arm  106  is the axis of rotation. The two holes  151  further to the edge of the proximal end  126  of the arm  106  are the receiving pinholes for the spring locking pin mechanism  114 . The four holes  180  to the edges of the distal end  128  of the arm  106  serve to mechanically mount the brushless electric motor  134  to the arm  106 . 
     It will be understood that the folding rotor arms  106  of the UAV  100  of the present invention can be collapsed, i.e., folded back into a collapsed position when the UAV  100  is being transported or stored such that the motors  136  associated with the rotors  108  define the four outermost corners of a square or rectangle. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Although any methods and materials similar or equivalent to those described can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications and patent documents referenced in the present invention are incorporated herein by reference. 
     While the principles of the invention have been made clear in illustrative embodiments, there will be immediately obvious to those skilled in the art many modifications of structure, arrangement, proportions, the elements, materials, and components used in the practice of the invention, and otherwise, which are particularly adapted to specific environments and operative requirements without departing from those principles. The appended claims are intended to cover and embrace any and all such modifications, with the limits only of the true purview, spirit and scope of the invention.