JP7784396B2 - Hula hoop and method for manufacturing hula hoop - Google Patents

Description

The present invention relates to a hula hoop as a toy or a sports or performance implement, and to a method for manufacturing the same.

Hula hoops have long been popular as toys for people of all ages and genders, and are also popular as equipment in competitions and performances such as rhythmic gymnastics and dance. Hula hoops are used by rotating them around a part of the body such as the neck, waist, arms, or legs, by throwing them into the air, or by dropping them to the ground and bouncing them. In general, since spinning is the basic action of the hula hoop, many efforts have been made to improve the efficiency of rotation and reduce the strain on parts of the body.

For example, Patent Document 1 discloses a hula hoop equipped with vertical ribs on the side that comes into contact with the body during rotation to increase frictional resistance in the direction of rotation to accelerate the rotation, and horizontal ribs to increase frictional resistance in the direction of fall to prevent the hoop from falling. This configuration is expected to reduce slippage between the body and the hoop in the direction of rotation, as well as slippage between the body and the hoop in the direction of fall (see "Summary").

JP 2011-24987 A

However, Patent Document 1 makes no mention of durability, stability, or operability. In other words, the hula hoop described in Patent Document 1 is intended for beginners who are trying to master the basic movements described above, and is not suitable for experienced users who are trying to master movements that are more difficult than the basic movements described above, or for athletes or performers who throw it into the air or drop it on the ground to bounce or roll it. In other words, durability, stability, and operability are important factors that beginners and above consider when choosing a hula hoop.

Some conventional hula hoops are made by connecting the two longitudinal ends of a thin, cylindrical rod with a joint inserted into the tube to form a ring-like annular body. In other words, the end surface area of these longitudinal ends is too small to be glued, so they must be connected via the joint. The joint specifications are, for example, 40-120 mm in length and 9-26 g in weight. For this reason, when a hula hoop falls from the sky and hits the ground, the impact can cause the annular body to come loose from the joint, resulting in damage. For this reason, hula hoops, particularly those intended for athletes and performers, should be designed to withstand certain impacts during use and withstand breakage.

Furthermore, conventional hula hoops tend to sway vertically and/or horizontally when thrown into the air or when falling or rolling to the ground, forcing athletes and performers to take into consideration the degree of sway of the hula hoop. In other words, for athletes and performers, the specifications of a hula hoop should at the very least not reduce the precision of their competition or performance, and preferably should contribute to improving said precision.

The object of the present invention is to provide a hula hoop and a method for manufacturing a hula hoop that has durability suitable for the impacts experienced during use in competitions and performances, stability suitable for the precision required for such use, and operability that contributes to improving the precision of competitions and performances.

In other words, the hula hoop of the present invention comprises a cylindrical main body portion that forms a ring-shaped outer shape, and a protrusion portion formed to protrude inward from the inner surface of the main body portion , the protrusion portion appearing on both end surfaces of the ring-shaped body in the ring direction to be bonded, and the ratio of the thickness of the main body portion to the protrusion amount of the protrusion portion is 1:2 to 8:1.

It is desirable that at least one pair of protrusions be formed in opposing positions.

It is desirable that the protrusions be formed continuously in the annular direction of the main body.

In addition, the method for manufacturing a hula hoop in the present invention is characterized by including the steps of pouring thermoplastic resin into a linear mold to obtain a rod-shaped body having a cylindrical main body and protrusions formed to protrude inward from the inner surface of the main body, with the ratio of the thickness of the main body to the amount of protrusion of the protrusions being 1:2 to 8:1 ; fitting the rod-shaped body into an annular mold to obtain an annular body; and bonding the end faces of the annular body together.

This invention is expected to provide durability suitable for the impacts experienced during use in competitions and performances, stability suitable for the precision required for such use, and operability that contributes to improving the precision of competitions and performances.

1A and 1B are a plan view and a side view, respectively, of a hula hoop according to one embodiment of the present invention. This is an end view of the hula hoop in a direction perpendicular to the circular direction (XX part of Figure 1(A)). 1B is a partially enlarged end view of the hula hoop in the circular direction (YY portion in FIG. 1B). 1A to 1C are diagrams illustrating the manufacturing process of the above-mentioned hula hoop.

The following describes a hula hoop (hereinafter referred to as "the present hula hoop F") and a method for manufacturing the hula hoop (hereinafter referred to as "the present manufacturing method") according to one embodiment of the present invention, with reference to Figures 1 through 3. In these figures, where multiple identical parts exist, some parts are numbered only for one part. For ease of explanation, certain parts and their extension lines are indicated by imaginary lines (two-dot chain lines), and cross-sectional areas are indicated by hatching.

As shown in Figures 1 and 2A, this hula hoop F has a cylindrical main body 1 that forms a ring-shaped outer shape in a plan view, and protrusions 2 that protrude inward from the inner surface of the main body 1. Its uses are not limited, and it may be used as a toy, but it is more suitable as a tool for sports and performances such as rhythmic gymnastics and dance. This hula hoop F is formed by molding a rod-shaped body with portions corresponding to the main body 1 and protrusions 2 into a ring-shaped body, and then gluing together the end faces of the ring-shaped body that correspond to both longitudinal ends of the rod-shaped body.

The material of this hula hoop F is not particularly limited, but may be metal such as aluminum, stainless steel, titanium, or an alloy of these, but is preferably light in weight and low in density, such as a lightweight and flexible thermoplastic resin such as polyethylene, high-density polyethylene, or polyvinyl chloride, or a mixture of these thermoplastic resins with pulp, talc, or bioplastics.

The weight of the hula hoop F is not particularly limited, but may be, for example, 100g or more but less than 1500g as a toy or as equipment for competitions or performances, 260g or more but less than 300g as equipment for juniors aged 15 or under, and 300g or more but less than 350g as equipment for seniors aged 16 or over.

As shown in Figure 1(B), the diameter W1 of the hula hoop F is not particularly limited, but may be, for example, 500 mm or more and less than 1500 mm as a toy or as equipment for competitions or performances, 700 mm or more and less than 900 mm as equipment for rhythmic gymnastics, including for juniors aged 15 and under, and 800 mm or more and less than 900 mm as equipment for seniors aged 16 and over.

As shown in Figure 2A, the diameter W2 of the main body 1 is not particularly limited, but may be, for example, 10 mm or more and less than 30 mm for use as a toy or as equipment for competitions or performances, and 15 mm or more and less than 20 mm for use as rhythmic gymnastics equipment, including for juniors aged 15 or under.

As shown in Figures 2A and 2B, the thickness W3 of the main body 1 is not particularly limited, but may be, for example, 1.5 mm or more and less than 4 mm when used as a toy or as equipment for competitions or performances, and 1.5 mm or more and less than 3 mm when used as equipment for rhythmic gymnastics, including for juniors aged 15 or under. The thickness W3 of the main body 1 varies depending on the material of the hula hoop F described above, and may be thicker, for example, when used with a relatively low-density material.

As shown in Figure 2A, the bisector of the protrusion 2 is located on the center line L of the main body 1. In other words, the protrusion 2 is more likely to improve stability if it has a shape and orientation that is bisected by this center line L. However, the protrusion 2 may have a shape that is not bisected by this center line L, or may be oriented so as to be inclined at a predetermined angle relative to the center line L.

The protrusion amount W4 of the protrusion 2 is not particularly limited, but may be between 0.5 mm and 3 mm for toys or as equipment for competitions or performances, and between 1 mm and 2 mm for rhythmic gymnastics equipment, including for juniors aged 15 and under. If it is less than 0.5 mm, the protrusion amount W4 is too small, making it difficult to bond the end faces of the ring-shaped body together, while if it is 3 mm or more, the protrusion amount W4 is too large, which may result in excessive weight, strength, and/or rigidity of the hula hoop F.

The width W5 of the protrusion 2 is approximately equal to the protrusion amount 4, but may be thinner or thicker than the protrusion amount 4. If it is too thin, it will be difficult to bond the end faces of the annular body together, and if it is too thick, the weight, strength, and/or rigidity of the hula hoop F may increase too much.

The ratio of the thickness W3 of the main body 1 to the protrusion amount W4 of the protrusion 2 is not particularly limited, but is generally between 1:2 and 8:1, with a ratio of 3:4 to 3:1 being appropriate for rhythmic gymnastics equipment, including for juniors aged 15 and under. With this configuration, the protrusion 2 increases the adhesive area and strengthens the adhesive strength between the end faces of the ring-shaped body, making the hula hoop F less likely to break. Furthermore, the strength and rigidity of the main body 1 are increased, which is expected to make the hula hoop F less likely to wobble (distort) even when thrown, dropped, or spun.

The protrusion amount W4 of the protrusions 2 may be relatively greater or less than the thickness W3 of the main body 1, but if the protrusions 2 protrude at a ratio greater than 1:2 relative to the desired weight, the main body 1 will be too thin and the hula hoop F may be prone to breakage; if the protrusions 2 protrude at a ratio less than 8:1, the strength and rigidity of the main body 1 will be too low and the hula hoop F may be prone to shaking.

As shown in Figure 2A, the innermost part of the end face shape of the protrusion 2 is an arc, but this is not limited to this and it may be a straight line or an obtuse angle. The radius of the arc at the tip of the end face shape of the protrusion 2 (hereinafter also referred to as the "R radius") is 0.5 mm or more and less than 1 mm. If it is less than 0.5 mm, the end face shape of the protrusion 2 will be too thin, and if it is 1 mm or more, it may be difficult to form it into an arc.

The protrusions 2 are formed radially around the circumference of the main body 1, and are formed in four sets at opposing positions. However, one set, two to three sets, or five or more sets may be formed. Forming at least one set at opposing positions is expected to have the effect of making it easier to achieve the desired strength and rigidity of the main body 1. In other words, the number or number of sets of protrusions 2 and their positions around the circumference of the main body 1 affect the strength and rigidity of the main body 1, and the more evenly the protrusions 2 are formed around the circumference of the main body 1, the easier it is to achieve the desired strength and rigidity of the main body 1. One or more protrusions 2 may be formed in offset positions that do not face each other, as long as an effect equivalent to that described above can be expected.

As shown in Figure 2B, the protrusions 2 are formed continuously in the annular direction of the main body 1, which makes it easier to achieve the desired strength and rigidity of the main body 1, but they may also be formed discontinuously, in other words, two or more protrusions may be formed at predetermined intervals. In other words, the number of protrusions 2 in the annular direction of the main body 1 affects the strength and rigidity of the main body 1, and the more protrusions 2 are formed continuously in the annular direction of the main body 1, with one or more protrusions 2 formed closely and evenly spaced, the easier it is to achieve the desired strength and rigidity of the main body 1.

As shown in Figure 3, this manufacturing method first involves pouring thermoplastic resin into a linear mold C1 to obtain a rod-shaped body S1, which has a cylindrical main body and protrusions formed on the inner surface of the main body, protruding inward (hereinafter referred to as the "rod-shaped body molding process"). The linear mold C1 has an outer cylindrical body that is circular in cross section and an inner cylindrical body that is molded with a concave-convex shape. Thermoplastic resin is poured between the outer and inner cylindrical bodies. After a predetermined time has passed, the outer and inner cylindrical bodies are removed to form the rod-shaped body S1. Next, the rod-shaped body S is inserted into an annular mold C2 to obtain an annular body S2 (hereinafter referred to as the "annular body molding process"). The end faces of the annular body S2, which correspond to the longitudinal end faces of the rod-shaped body S1, are then bonded together with a predetermined adhesive, and thin tape is wrapped around the outside of the bonded area to conceal the boundary between the end faces (hereinafter referred to as the "adhesion process"). Through these steps, the production of this hula hoop F is completed.

During the bonding process, the end faces of the annular body S2 have an area equal to the combined area of the main body and the protrusions. This means that the bonding area between these end faces is larger than the area of the main body alone, making bonding easier and improving the bonding strength between the end faces. In other words, the protrusions increase the bonding area between the end faces, achieving the desired bonding strength. This eliminates the need for additional reinforcement, such as connecting the end faces via a joint material and wrapping tape around the boundary between the end faces, as is conventional. In other words, the elimination of this reinforcement eliminates the partial imbalances, such as weight and bulging around the end faces, that are associated with the joint material and tape. This allows for a uniform weight and thickness around the entire circumference. This avoids distortion of the center of gravity of the entire hula hoop and minimizes deformation during use, thereby improving the durability, stability, and operability of the hula hoop.

This manufacturing method may involve any step that results in the production of the hula hoop F. For example, the rod-shaped body molding step may involve a step of obtaining a thermoplastic resin sheet having linear protrusions formed at predetermined intervals, and a step of rolling this thermoplastic resin sheet to obtain a long, tubular rod-shaped body.

<Examples and Comparative Examples>
The hula hoop F, which corresponds to the example, is made from high-density polyethylene (composition ratio 100%), has an overall diameter W1 of 810 mm, weighs 320 g, has a diameter W2 of main body 1 of 17.5 mm, a thickness W3 of main body 1 of 2.35 mm, a protrusion amount W4 and width W5 of protrusion 2 of 1.5 mm, a ratio of the thickness of main body 1 to the protrusion amount W4 of protrusion 2 of 8:5, a radius R of the tip of protrusion 2 of 0.75 mm, there are eight protrusions 2 (four sets), the protrusions 2 are arranged in opposing positions and at equal intervals, and the end faces of the ring-shaped body are bonded together with adhesive and tape is wrapped around the outer periphery of this bonded portion.

The hula hoop corresponding to the comparative example is made of a specified resin or similar material, has an overall diameter W of approximately 810 mm, weighs approximately 320 g, has a main body diameter of approximately 17.5 mm, a specified thickness of the main body, and is approximately 40 mm long, with the ends of the ring-shaped body connected together via a joint material and tape wrapped around the outer periphery of the bonded parts.

<Evaluation test method>
To evaluate durability, the Examples and Comparative Examples are dropped from a height of 5 m to the ground to check for damage. To evaluate stability, the Examples and Comparative Examples are used as rhythmic gymnastics equipment in a given routine to check for shaking.

<Test Results>

These results show that in the example, the protrusions 2 increased the adhesive surface area, thereby increasing the adhesive strength between the end faces of the ring-shaped body, and therefore the hula hoop F did not break. Furthermore, because the strength and rigidity of the main body 1 were increased, the hula hoop F was less likely to shake (distort) even when thrown, dropped, or spun.

In addition, the material of the Example has a lower density than the Comparative Example, and when both have the same weight, the end area in the X-X direction shown in Figure 2A of the Example is larger than that of the Comparative Example. As a result, the Example is relatively softer than the Comparative Example and has better cushioning properties for the body, which reduced the physical pain felt by the subject.

In other words, the overall durability of the present embodiment of hula hoop F has been improved, making it less likely to deform or chip, crack, or break at joints, etc. Furthermore, its improved stability makes it easier for it to rise, fall, roll forward, and return to its original position, and it has been confirmed that these uses, including the use of the hula hoop, contribute to improved operability.

The hula hoop and manufacturing method described in this embodiment are not limited to the above, and include the position, shape, and dimensions of all parts, the relationships between parts, the order of processes, and the relationships between processes, as long as the same effects are obtained.

F: hula hoop 1: main body 2: protrusion S1: rod-shaped body S2: ring-shaped body

Claims (4)

a cylindrical main body portion that forms the outer shape of the annular body ;
a protrusion formed to protrude inward from the inner surface of the main body,
The protrusions appear on both end surfaces of the annular body in the annular direction to be bonded,
A hula hoop characterized in that the ratio of the thickness of the main body to the protrusion amount of the protrusions is 1:2 to 8:1. The hula hoop according to claim 1, wherein at least one pair of protrusions are formed at opposing positions. The hula hoop according to claim 1, wherein the protrusions are formed continuously in the annular direction of the main body. a step of pouring a thermoplastic resin into a linear mold to obtain a rod-shaped body having a cylindrical main body and protrusions formed so as to protrude inward from the inner surface of the main body , the ratio of the thickness of the main body to the protrusion amount of the protrusion being 1:2 to 8:1 ;
a step of fitting the rod-shaped body into an annular mold to obtain an annular body;
and a step of bonding the end faces of the annular body together.