JP2005130902A - Boomerang - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boomerang which achieves a change in the height of the turning track and the size of the turning radius with an intensified lift as generated under the air motion with the slant surfaces as well while obtaining varied flying altitudes by employing a resin foam with a low specific gravity and a high buffer strength as the material. <P>SOLUTION: The boomerang has a thin foam body which comprises the center part and three turning arms while the center of the body is made to overlap the centroid rotating shaft. Each of the turning arms has the base part and a wing part and the base parts extend outward radially and at an equal angle integrally toward the circumference from the center part. The wing parts extend outward to the respective tips of the wings integrally at a certain angle from the tail ends of the respective base parts. The wing parts are given as main geometric parameters included angles with the center line and the slant surfaces. The slant surfaces are positioned on the bottom part and extend to the respective tips of the wings from the front rims of the respective wing parts. The outline cross sections of the respective wing parts are defined by the front rims, wing planes and rear rims respectively. The varied flying altitudes of the boomerang can be obtained by selecting the included angles with the center line as mentioned above while the lift can be intensified under the air motion with the slant surfaces as well, thereby achieving the free change in the height of the turning track and the size of the turning radius of the boomerang. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a boomerang, and more particularly, to a boomerang comprising a thin foamed body including a center part and three pivot arms, the center of gravity rotation axis of which overlaps the center of the body. Each swivel arm has a base part and a wing part, and the base part extends radially and equiangularly from the periphery of the center part to the outside and extends to the tip of the wing part. Extends outward from the tail of the base at a certain angle to the tip of the wing, and the main geometric parameters of the wing consist of the depression angle and slope of the center line, the slope being at the bottom of the boomerang Located, extending from the leading edge of the wing to the leading edge of the tip of the wing, and the outer cross section of the wing consists of the leading edge, the wing plane, and the trailing edge, respectively, and select the depression angle of such center line The different flight altitudes of the boomerangs can be obtained by this, and the lift generated during the air movement can also be increased by the slope, thereby changing the boomerang's turning trajectory and the turning radius.

  Boomerang is a toy and sport that, after being thrown out, returns to its original position after continuing to turn. At present, commercially available boomerangs have many special and novel shapes due to their outline design. However, basically, the boomerang swivel arm profile is close to the plane of the wing of the airplane. Produces a lift that acts on the boomerang's swivel arm, and the boomerang swivels and moves forward, while at the same time it creates a lift by aerodynamic motion by the Benori principle and returns to its original position. It keeps turning until it returns.只, the safety of the swirling flight that boomerang continued to fly back had the following drawbacks, so we tried to improve it as much as possible.

  Most boomerang materials are made of wood or plastic, and when manufactured using wood or plastic, the boomerang swivel arm is given sufficient thickness and weight, and the swivel arm is lifted by air movement. However, the boomerang manufactured using a hard material is feared for safety and has a certain limit on the age of the user.

  The conventional foam boomerang is as claimed in US Pat. No. 5,490,678 (hereinafter referred to as an example bill), and its main structure is that a plurality of arms extend radially from the center of the boomerang, and the radial shape of the arms. The shaft depression angle is characterized in that it is distributed symmetrically on the arms as shown in FIGS. 4 to 6; and the main drawback in its construction is the vertical sectional shape of the arm center line of the above-mentioned example However, in such a cross-sectional design, the example boomerang swivels and moves forward, and at the same time the lift generated by the air motion raises the example boomerang. It is not easy to make the ascending altitude at the time of turning relatively high, to make the radius of the turning flight by detouring continuously relatively large, and to fly back to the throwing hand.

  As described above, the above conventional ones still have many drawbacks and are not a good design.

In light of the above-mentioned many disadvantages derived from the conventional boomerang, the present inventor tried to improve as much as possible, and as a result of studying for many years, finally completed the research and development of the boomerang according to the present invention.

  An object of the present invention is to adopt a boomerang material by adopting a foamed plastic having a low specific gravity and a high buffering force.

Another object of the present invention is to provide a boomerang that is not soft and hard, and has different turning lines and different turning radii by selecting the depression angle of the center line.

As a solution to the thin foam body (boomerang) that can achieve the object of the above patent, a thin foam body that includes a center part and three arms and whose center of gravity rotation axis overlaps the center of the body; The swivel arm has a base portion and a wing portion, and the base portion extends radially and uniformly from the periphery of the center portion to the outside, and the wing portion has an angle from the tail end of the base portion. The main geometric parameters of the wing part consist of the depression angle and the slope of the center line, which is located at the bottom of the boomerang, Boomerangs with different flight altitudes are selected by selecting the depression angle of the center line, which extends from the leading edge to the leading edge of the wing tip, and the outer cross-section of the wing part consists of the leading edge, wing plane and trailing edge, respectively. Can be manufactured at the same time By design, to increase the lift of the boomerang bottom, can result in a relatively small turning flight range of the boomerang.

The boomerang provided by the present invention has the following advantages when compared with the above-mentioned example and other conventional techniques.
The present invention forms a thin foam body with a soft foam material, and instead of a general wood or plastic boomerang, when it is manufactured, it is foamed like popcorn and filled into an injection mold simply by heating the raw material In addition, the soft boomerang is integrally molded by inflating and welding, so that it is not only light in weight but does not cause injury even if it hits the human body.
The center line depression angle of the base part and the wing part of the present invention is designed from 12 degrees to 30 degrees, and when the depression angle of the center line is relatively small by combining the low specific gravity soft foam material of the present invention, the thin foam body rises. When the depression angle of the center line is relatively large, the flight line of the thin foam body is relatively low and flat, and returns at a low angle.

The above detailed description is a specific description of the preferred embodiment of the present invention, but the embodiment does not limit the scope of the claims of the present invention and is equivalent to the technical spirit of the present invention. All implementations or variations of are intended to be included within the scope of the claims.

  1 to 3, a boomerang provided by the present invention mainly includes a center portion 11 and three swivel arms 12, and a thin foam body whose center of gravity rotation axis overlaps the center of the body. 1 and a base 121 and a wing 122 provided on the swivel arm 12 of the thin foam body 1. The base 121 is integrated radially and equiangularly from the periphery of the central portion 11 to the outside and extends to the tip 123 of the wing. The wing 122 is integrated at a certain angle from the tail end of the base 121. And extending outwards to the tip of the wing, and the main geometric parameters of the wing 122 are the centerline depression angle θ1 and the slope 14, which is located at the bottom of the boomerang, and the wing 122 The leading edge 131 extends from the leading edge 131 to the leading edge 131 of the blade tip 123.

  Referring to FIGS. 3A to 3C, the blade section of the wing portion 122 is constituted by a leading edge 131, a wing plane 132, and a trailing edge 133. In addition, the following important names are given. Yes. <1> Wing chord width (W): The width from the leading edge 131 to the trailing edge 133 of the wing portion 122 is about 70 mm or less. <2> Thickness of wing (H): Thickness of wing portion 122, about 8 mm to 20 mm. <3> Wing tip 123: The outermost point extending outward from the wing 122.

  By the way, the boomerang is divided into two types, right-handed and left-handed. In any case, one side with a slight arc degree is always inward (thrower) and the plane part is outward. First, the boomerang according to the present invention will be described using the right hand as an example. At the moment when the boomerang is thrown out, the surface angle of the thin foam body 1 must be close to the vertical line (the surface angle is determined by the magnitude of the wind speed). After being thrown out, the special wing cross section of the base 121 and the wing 122 (the cross section approximates the shape of the aircraft wing) and the centerline depression angle θ1 are the base 121 and the wing. The thrust of the airflow is formed on one side of the portion 122, and lift is generated on the other side, and the direction of the lift is from right to left as viewed from the thrower. In addition, the velocity above the center of gravity of the base 121 and the wing 122 is faster (forward flight plus turning), the resulting lift is larger, the velocity below the center of gravity is slower (forward flight minus turning), and the resulting lift is smaller. The difference between the two forms a moment of force acting on the thin foam main body 1 and turns the thin foam main body 1 to the left. However, the centerline depression angle θ1 of the base 121 and the wing 122 according to the present invention is from 12 degrees. When the angle of the centerline depression angle θ1 is smaller, the thin foam body 1 is likely to rise and fly back at a higher angle; when the angle of the centerline depression angle θ1 is larger, the thin foaming is performed. The flight route of the main body 1 is relatively low and flat and returns at a low angle.

At the same time, in each base 121 and wing 122, an interference airflow is generated in front of the center of gravity and behind the center of gravity, resulting in a difference in lift. Generally, when the center of gravity is in the front, the lift is larger, and when the center of gravity is in the rear, the lift is smaller. The moment of the force formed by the difference between the front and the rear gradually warps the thin foam body 1 to the right. The boomerang according to the present invention is designed so that the centerline depression angle θ1 of the base 121 and the wing part 122 is designed to be 12 degrees to 30 degrees. This design makes a relatively low and flat flight route, and the depression angle θ1. Depending on the size of each type, you can make each type of product with different levels of flight routes. Therefore, when the thin foam body 1 turns and rises while gradually curving to the right, and rises to the highest point, the thin foam body 1 returns by the remaining swirling inertial mass. Is directly proportional to the rotational inertial mass and inversely proportional to lift. The slope 14 according to the present invention is located at the bottom of the boomerang and extends from the leading edge 131 of the wing 122 to the leading edge 131 of the tip 123 of the wing, and the design of the slope 14 lifts the bottom of the boomerang. , And the return route after turning flight and the turning radius can be changed.

Schematic illustrating the centerline depression angle of the present boomerang Top view of the boomerang in FIG. (A): AA sectional view of the present boomerang, (B): BB sectional view of the present boomerang, (C): CC sectional view of the present boomerang. Schematic diagram of a traditional boomerang Schematic diagram of arm centerline and cross-sectional position of conventional boomerang (A): AA sectional view of a conventional boomerang, (B): BB sectional view of a conventional boomerang, (C): CC sectional view of a conventional boomerang, (D): Conventional boomerang DD cross section

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thin foam main body 11 ... Center part 12 ... Swivel arm 121 / Base part 122 / Wing part 123 / Wing | tip part tip θ1 ... Center line depression angle W ... Chord width H ... Wing thickness 131, leading edge 132, wing plane 133, trailing edge 14, slope

Claims (1)

A central part having a center of gravity rotation axis at the center point of the main body;
Three swivel arms and the swivel arm respectively have a base portion and a wing portion, and the base portion has a radial shape around the center portion and extends outward at an equal angle.
The wing part is integrated at a certain angle from the tail end of the base part and extends outward to the wing part tip,
The main geometric parameters of the wing part are a centerline depression angle and a slope, and the slope is located at the bottom of the boomerang, extends from the leading edge of the wing part to the tip of the wing, and the extension position of the wing part Is a boomerang characterized in that it extends from the half radius of the thin foam body at the same time as a center line depression angle of 12 to 30 degrees.

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