Patent Publication Number: US-8113904-B1

Title: Flying toy having boomerang flight characteristics and controlled landing abilities

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     In general, the present invention relates to toy helicopters. More particularly, the present invention relates to toy helicopters having rotors that are manually thrown as a boomerang. 
     2. Prior Art Description 
     Boomerangs have been used by the aboriginal peoples of Australia for thousands of years. 
     Boomerangs were originally developed as hunting tools. However, due to the looped flight pattern exhibited by a boomerang, boomerangs have significant play value and have therefore been commercialized as toys. 
     Originally, hunting boomerangs were carved out of wood and were intentionally made heavy so they would cause injury upon impact. Boomerangs designed as toys are made much smaller and lighter than hunting boomerangs. Furthermore, toy boomerangs are often made of soft plastic or foam to ensure that the boomerangs do not cause injury upon impact. 
     The original wooden boomerangs are generally V-shaped, having two intersecting wings. It has been discovered that when such a boomerang configuration is made of lightweight plastic or foam, the boomerang no longer flies in the looped path characteristic of a traditional boomerang. 
     In order to make a lightweight boomerang fly in a manner characteristic of a traditional wooden boomerang, the number of wings radially extending from the boomerang must be increased to three, four, or five. Furthermore, the wings must by symmetrically disposed about a common center point. By providing each wing with a shape of an airfoil, the toy boomerang will fly following a looped path. Such prior art toy boomerangs are exemplified by U.S. Pat. No. 3,403,910 to Claycomb, entitled Toy Boomerang, and U.S. Pat. No. 4,222,573 to Adler, entitled Boomerang. 
     In an attempt to increase the play value of a toy boomerang, toy manufacturers experimented with adding secondary objects to the toy boomerang. For example, helicopter bodies were connected to the bottom of the toy boomerang so that the toy boomerang would look like a helicopter in flight. Such prior art patents are exemplified by U.S. Pat. No. 4,708,682 to Schentrup, entitled Helicopter Toy. 
     A problem associated with connecting a secondary object to a toy boomerang is that the weight and the aerodynamic drag caused by the presence of the secondary object tends to hold the spinning wings of the toy boomerang into a single plane during flight. This causes the toy boomerang to fly in a straight line rather than to fly in the looped flight path characteristic of a traditional boomerang. Furthermore, since the mass of the rotors is greater than the mass of the secondary object, the toy is top heavy in flight. Consequently, such toys have a propensity to crash land or land upside down at the end of a throw. 
     A need therefore exists for a toy construction having a boomerang that can be joined to a secondary object, such as a helicopter body, wherein the presence of the secondary object does not inhibit the toy from flying in a looped path or inhibit the toy from landing upright. This need is met by the present invention as described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a flying toy assembly having a secondary body suspended from a boomerang rotor configuration. The rotor configuration includes a plurality of rotor blades that radially extend from a common hub area in a symmetrical pattern. The central hub area of the rotor configuration has a top surface, a bottom surface, and a predetermined thickness between said top surface and said bottom surface. An annular grommet extends through the central hub area. The grommet defines a hole having a length generally equal to the thickness of the central hub area. 
     A secondary body is attached to the grommet. A shaft extends from the secondary body. The shaft extends through the hole in the grommet, thereby joining the secondary body to the rotor configuration. 
     Stops are provided on the shaft. The stops are disposed a predetermined distance apart along the shaft. The predetermined distance is at least twice as long as the length of the hole in the grommet. Accordingly, when the shaft passes through the grommet, the rotor configuration is free to rotate about the shaft and reciprocally move along the shaft between the stops. The ability of the rotor configuration to move reciprocally along the shaft as it spins helps the flying toy assembly fly in a looped path and land upright. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present invention, reference is made to the following description of an exemplary embodiment thereof, considered in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of an exemplary embodiment of a flying toy assembly; 
         FIG. 2  is a partially cross-sectioned side view of the exemplary embodiment of  FIG. 1 ; and 
         FIG. 3  is an enlarged cross-sectional fragmented view of the portion of the flying toy assembly containing a shaft. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Although the present invention flying toy assembly can be embodied in many ways, such as a flying bird, the embodiment illustrated shows the toy configured as a helicopter. This embodiment is selected in order to set forth the best mode contemplated for the invention. The illustrated embodiment, however, is merely exemplary and should not be considered a limitation when interpreting the scope of the appended claims. 
     Referring to  FIG. 1  in conjunction with  FIG. 2  and  FIG. 3 , there is shown an exemplary embodiment of the present invention flying toy assembly  10  that is shaped as a toy helicopter. The flying toy assembly  10  includes a molded configuration of plastic rotors. The rotor configuration  12  includes at least three rotor blades  14  symmetrically extending from a common central hub area  16 . In the shown embodiment, four rotor blades  14  are present. However, any plurality of rotor blades  14  greater than three can be used. Each of the rotor blades  14  in the rotor configuration  12  is identical in shape and embodies the cross-sectional shape of an airfoil. The rotor configuration  12  would be considered a toy boomerang if not assembled into the flying toy assembly  10  of the present invention. 
     A hole  20  is formed in the geometric center of the rotor configuration  12 . Depending upon the type of plastic or foam used to mold the rotor configuration  12 , the hole can be formed straight through the hub area  16  or through a grommet  22  mounted in the hub area  16 . In the exemplary embodiment, a grommet  22  is shown. 
     The central hub area  16  of the rotor configuration  12  has a top surface  17  and a bottom surface  18 . The grommet  22  extends through the hub area  16  from the top surface  17  to the bottom surface  18 . The hole  20  has a predetermined length L 1  that is equal to the thickness of the hub area  16  containing the hole  20 . 
     A secondary body in the form of a fuselage body  24  is suspended from the blade rotor configuration  12 . In the shown embodiment, the fuselage body  24  is shaped as the body of a helicopter. However, it will be understood that other shapes can be used. For instance the fuselage body  24  can have the shape of a bird, a plane, or a flying superhero. Regardless of its configuration, the fuselage body  24  is preferably lightweight and soft, being molded from lightweight foam or being hollow with a thin plastic shell. A flat landing base  26  or set of landing gear is provided at the bottom of the fuselage body  24 . The landing base  26  enables the fuselage body  24  and the entire flying toy assembly  10  to rest upright on a flat horizontal surface. 
     A shaft  30  extends upwardly from the fuselage body  24 . The shaft  30  is permanently affixed to the fuselage body  24 . Accordingly, the shaft  30  cannot rotate independently. The shaft  30  has a top end  32  that is forked. That is, a slot  34  is formed down the center of the shaft  30 , creating two flexible prongs  36 . Lateral stops  38  are formed at the top end of each of the flexible prongs  36 , for a reason that will be later explained. 
     A bottom stop  40  is formed on the exterior of the shaft  30  a predetermined distance D 1  below the top end  32  of the shaft  30 . The shaft  30  has an outside diameter that is greater than the inside diameter of the hole  20  in the grommet  22 . Furthermore, both the lateral stops  38  and the bottom stop  40  have an outside diameter that is greater than the inside diameter of the hole  20  in the grommet  22 . The predetermined distance D 1  between the bottom stop  40  and the lateral stops  38  is preferably between one centimeter and four centimeters. The preferred length L 1  of the hole  20  in the grommet  22  is preferably between 2 millimeters and 8 millimeters. In ratio, it is preferred that the distance D 1  between the stop and the top end  32  of the shaft  30  is between two and four times as great as the length L 1  of the hole  20 . 
     Referring to  FIG. 3 , it can be seen that the grommet  22  of the rotor configuration  12  passes over the top end  32  of the shaft  30 . This is done by pressing the two flexible prongs  36  together until the lateral stops  38  come together in an area small enough to pass through the grommet  22 . Once the grommet  22  passes over the top end  32  of the shaft  30 , the flexible prongs  36  expand back to their original positions. This causes the grommet  22  and its surrounding rotor configuration  12  to become entrapped between the bottom stop  40  and the lateral stops  38  at the top end  32  of the shaft  30 . 
     The inside diameter of the hole  20  in the grommet  22  is greater than the outside diameter of the shaft  30 . Accordingly, the rotor configuration  12  rotates freely about the shaft  30 . Furthermore, the rotor configuration  12  is free to reciprocally move up and down the length of the shaft  30  in the range R 1  between the bottom stop  40  and the lateral stops  38 . As such, the rotor configuration  12  is free to move to a top position P 1  where the rotor configuration  12  abuts against the lateral stops  38  and a bottom position P 2 , where the rotor configuration  12  abuts against the bottom stop  40 . 
     When the rotor configuration  12  moves between the top position P 1  and the bottom position P 2 , the center of gravity for the entire flying toy assembly  10  changes. This ability to change the center of gravity supplies the flying toy assembly  10  with the ability to both fly in a looped path and land upright. 
     Referring back to all figures, it will be understood that in order to utilize the flying toy assembly  10 , a person grasps one of the rotor blades  14  extending from the rotor configuration  12 . The flying toy assembly  10  is then thrown in a manner where spin is applied to the rotor configuration  12 . The flying toy assembly  10  subsequently takes flight with the rotor configuration  12  spinning. The spinning of the rotor configuration  12  causes the various rotor blades  14  to provide lift during flight. The degree of lift depends upon the force of the throw, the rate of spin and the pitch formed in the rotor blades  14 . As the flying toy assembly  10  flies, different forces are applied to both the rotor configuration  12  and the fuselage body  24  suspended from the rotor configuration  12 . If those forces move the rotor configuration  12  away from the fuselage body  24 , the rotor configuration  12  moves up the shaft to the top position P 1 . Conversely, if forces move the rotor configuration  12  toward the fuselage body  24 , the rotor configuration  12  moves to its bottom position P 2 . Both types of forces are commonly experienced during flight. 
     As the position of the rotor configuration  12  changes, the center of gravity for the entire flying toy assembly  10  changes. The changes in the center of gravity help to alter the flight path of the flying toy assembly  10  and cause the flying toy assembly  10  to fly in a looped path, characteristic of a traditional boomerang. 
     As the rotational speed of the rotor configuration  12  decreases, the lift provided by the rotor configuration  12  decreases. At some point the lift of the rotor configuration  12  becomes secondary to gravity. The weight of the fuselage body  24  under the rotor configuration  12  moves to the bottom of the flying toy assembly  10 . As the flying toy assembly  10  descends to the ground, the landing base  26  on the bottom of the fuselage body  24  typically touches the ground first. Once in contact with the ground, gravity causes the rotor configuration  12  to fall along the shaft  30  to its bottom position P 2 . This lowers the center of gravity for the flying toy assembly  10  and makes the flying toy assembly  10  more stable. The result is that the flying toy assembly  10  stays upright on its landing base  26 , even as the rotor configuration  12  slows to a stop and the flying toy assembly  10  experiences any resonance forces exerted by imbalances in the slowing spinning rotor configuration  12 . Accordingly, the ability of the rotor configuration  12  to slide significantly along the shaft  30  enhances the ability of the flying toy assembly  10  to both fly in a looped path and consistently land upright. 
     It will be understood that the embodiment of the present invention that is illustrated and described is merely exemplary and that a person skilled in the art can make many variations to that embodiment. For instance, the number of rotors, the shape of the rotors, and the shape of the fuselage body can all be altered to the design choice of a manufacturer. All such embodiments are intended to be included within the scope of the present invention as defined by the claims.