SAFETY GOLF BALL FOR PRACTICE

Abstract

The present invention relates to a safety golf ball for practice and, more specifically, to a safety golf ball for practice, by which a similar effect to the practice using a real golf ball can be obtained and a safety accident can be prevented. To this end, the safety golf ball for practice includes a soft outer core on an existing inner core so as to have a fast elasticity recovery speed.

Description

TECHNICAL FIELD

The present invention relates to a safety golf ball for practice, and more specifically, to a safety golf ball for practice, which can obtain a similar effect to the practice using a real golf ball, and prevent accidents.

BACKGROUND ART

Golf is a game that a golfer hits a stopped ball with a golf club in a golf course having a plurality of holes to put the ball into the holes, so a golfer who completed the holes by the fewest hits is a winner. Recently, golfers are becoming increasingly popular, such as the winning of many excellent Korean pro-players. Accordingly, industries related to golf, golf goods, golf clothes, and the like are also growing.

The structure of the golf ball is very important since influencing on the driving distance and spin performance of the golf ball. In general, a golf ball is classified into a single-piece golf ball having a single structure, a two-piece golf ball having a two-layer structure including a core and a cover surrounding the core, a three-piece golf ball having a three-layer structure including a double core and a cover, a three-piece golf ball having a three-layer structure including a core and a double cover, a four-piece golf ball including one core and a three-layer cover, a four-piece golf ball including a double core and a double cover, and a four-piece golf ball including a triple core and one cover. Such golf balls classified as above are generally very hard to be used outdoors, but have several disadvantages in that they generate a loud noise and may cause a risk of injury by the hit golf ball when being hit indoors. So, such golf balls are not utilized for indoor sports.

In addition, there is no appropriate golf balls used for screen golf using a simulator, so golfers perform simulation using golf balls used in a field. In such a case, as described above, since the golf balls generate a loud noise and may cause a risk of injury by the hit golf ball when being hit, in order to solve such problems, it is necessary to install lots of shock absorbers in booths.

Meanwhile, in recent years, some of balls for practice have been developed, but golfers cannot perform practice properly since the balls for practice are quite unlike real golf balls. Accordingly, there is a need to develop a safety golf ball for practice, which can be safely used indoors and can similarly realize the performance of a real golf ball as much as possible.

PATENT LITERATURE

Patent Documents

• (Patent Document) Korean Utility Model Registration No. 20-0318661

DISCLOSURE

Technical Problem

Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the related art, and it is an object of the present invention to provide a safety golf ball for practice, which can obtain a similar effect to the practice using a real golf ball, and prevent accidents.

The foregoing and other objects and advantages of the present invention will become apparent from the following description of the preferred embodiments.

Technical Solution

The object of the present invention is achieved by a safety golf ball for practice, which has an outer core which is soft and has elastic recovery so that hardness is gradually reduced outward.

To accomplish the above-mentioned objects, according to the present invention, there is provided a safety golf ball for practice including: an inner core; a soft outer core having hardness lower than that of the inner core; and a cover positioned outside, wherein the hardness of the outer core is gradually reduced outward.

Here, the outer core may be a multi-piece golf ball having three or more layers covering the inner core.

In addition, the outer core may be made of a material such as a polyurethane sponge.

In addition, the hardness of the outer core may gradually decrease outward.

In addition, a rotation recognition pattern may be formed on the cover of the safety golf ball for practice.

In this instance, the rotation recognition pattern may include a mark including two or more bending structures, a mark in which two points and a straight line are combined, a mark in which three points are combined, or a portion of the shape of a QR code.

Advantageous Effects

According to the present invention, the safety golf ball for practice may have a similar effect to the practice using a real golf ball when a golfer practices full-swing or half-swing, since including the existing inner core and the soft outer core.

In addition, the safety golf ball for practice can be used repeatedly by maintaining a proper level of elasticity, and can prevent accidents, and thus may be used indoors.

The effects of the present invention are not limited to the above-mentioned effects and further effects not described above will be clearly understood by those skilled in the art.

DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a portion of a golf ball according to an embodiment of the present invention.

FIG. 2 is a view illustrating an example of rotation recognition patterns, which may be formed on a golf ball cover according to an embodiment of the present invention.

FIG. 3 is a graph showing an average driving distance after hitting a real golf ball and balls of an embodiment 1 and an embodiment 2 using a simulator used in a screen golf.

SEQUENCE LIST

• • 100: Safety golf ball for practice
  • 10: Inner core
  • 20: Outer core
  • 30: Cover

MODE FOR INVENTION

Hereinafter, the present invention will be described in detail with reference to the embodiments of the present invention and the drawings. It will be apparent to those of ordinary skill in the art that these embodiments are merely illustrative to describe the present invention in more detail, and the scope of the present disclosure is not limited by these embodiments.

Furthermore, unless otherwise defined, 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 pertains, and when conflicting, the description of the present invention including definitions will take precedence.

In order to clearly describe the proposed invention in the drawings, parts that are not related to the description have been omitted, and like reference numerals refer to like components throughout the specification. In addition, Also, when a part “includes” or “comprises” an element, unless there is a particular description contrary thereto, the part can further include other elements, not excluding the other elements. In addition, the term “unit” described in the specification refers to one unit or block for performing a specific function.

In each of the steps, an identification code (first, second, etc.) is used for convenience of description, and an identification code does not describe the order of each step, and each of the steps may be performed differently from the order in which the context clearly indicates a specific order. That is, each of the steps may be performed in the same order as the specified order or may be executed substantially simultaneously or in the opposite order.

FIG. 1 is a partial cutaway cross-sectional view of a golf ball 100 according to an embodiment of the present invention.

Referring to FIG. 1, the safety golf ball 100 for practice according to an embodiment of the present invention includes an inner core 10 which is the same as that of an existing golf ball, an outer core 20 which is soft and has a fast elastic recovery, and a cover 30 located outside the outer core 20.

In a case of a two-piece ball, which is frequently used for practice, the inner core 10 of the existing golf ball may be made of polybutadiene, tungsten, or the like. In this case, the most important variable is hardness. A golf ball with high hardness is for superior, and a golf ball with low hardness is for inferior.

The flying principle of the golf ball is as follows. While the golf ball which receives power when a golf club hits the golf ball is sufficiently deformed and restored, impact energy is converted into kinetic energy so that the golf ball can fly forward. In this instance, if the hardness is high, the energy conversion efficiency is lowered, so lots of impact energy remains.

In addition, since a reverse rotation is applied to the golf ball due to an angle of an iron club, the golf ball receives sufficiently repulsive force, and then, the impact energy is converted into rotation and repulsive force, so that the golf ball can fly. In this instance, even though the same force is applied, when the golf ball is transformed greatly and the ball shows the maximum rubber resilience, the initial launch speed may be increased, the rotation may be performed well, and the flight angle may be increased sufficiently.

Accordingly, technologies for making golf balls which are soft and safe and can make an appropriate driving distance have been developed.

In order to achieve the above, in the present invention, the outer core 20, which is soft and has a fast elastic recovery, was made of a material such as a polyurethane sponge.

In this instance, the polyurethane sponge is a foam body having an elastic restoring force, that is, a force to return to an initial state when being pressed and released. Because almost all of empty spaces in a sponge are connected, the elastic recovery is possible since air escaped when the sponge is pressed fills the place when the sponge is returned to the original state. The polyurethane sponge may be varied in hardness and elastic recovery speed according to a foaming ratio, that is, an air content per unit volume.

Additionally, with respect to elasticity, since the elasticity and the driving distance of the golf ball are proportional to each other, the driving distance may not decrease by using a sponge having a fast elastic recovery when being compared with general golf balls. In addition, in order to make up for

With respect to hardness, in order to compensate for the decrease in the driving distance since the outer core 20 is lower in hardness than general golf balls, the outer core 20 may be designed to have an n-layer structure in such a way that hardness is gradually reduced outward by varying the foaming ratio of the polyurethane sponge for each layer.

The cover 30 may be manufactured to have a thickness of 1 mm to 3 mm using synthetic resin such as urethane or ionomer, and various pigments may be added to make the manufactured golf balls in a variety of colors.

In addition, various rotation recognition patterns (patterns, uneven structures, etc.) may be formed on the cover 30 of the golf ball so as to be used in a simulation device for a screen golf that calculates the trajectory of the golf ball by measuring the rotational speed after hitting.

FIG. 2 is a view illustrating an example of the rotation recognition pattern formed on the golf ball cover 30 according to an embodiment of the present disclosure.

The rotation recognition pattern is recognized (photographed) by an optical recognition apparatus, such as a camera to measure the rotation for a simulation. In order to measure a rotational speed of the golf ball by an optical recognition apparatus such as a sensor, it is necessary that a sensor photographs the hit golf ball at two or more places spaced apart from each other at regular intervals in a hitting direction after hitting, and measures a position change of the rotation recognition pattern for a short time.

In this manner, in order to measure the rotational speed of the golf ball by the optical recognition device, the rotation recognition pattern of the present invention may include a mark including two or more bending structures, a mark in which two points and a straight line are combined, a mark in which three points are combined, or a portion of the shape of a QR code.

Referring to FIG. 2, there are various rotation recognition patterns, and the rotation recognition patterns may be modified within the scope of the present invention. In addition, the rotation recognition pattern is formed on one side of the cover 30 of the golf ball 100 to easily check a traveling direction and a rotational direction of the golf ball 100, and includes at least one of figures or characters.

Referring to FIG. 2A illustrates a mark in which a ‘E’ shape including two or more bending structures is inverted horizontally, and FIG. 2B illustrates a mark having a ‘Z’ shape including two or more bending structures, FIG. 2C illustrates a mark having a ‘T’ shape including two or more bending structures, FIG. 2D illustrates a mark in which two points and a straight line are combined and the two points are located on the same line, FIG. 2E illustrates a mark representing a portion of the shape of a QR code, and FIG. 2F illustrates a mark in which three points are combined wherein two points having the same size are located on the same line and the remainder has a different size.

The rotational speed of the golf ball can be easily calculated by analyzing the position change of the pattern on the basis of shapes of patterns shown on two images photographed at two or more places after hitting the golf ball since the patterns do not have a symmetric structure therein.

Specifically, the rotational speed of the golf ball through the instantaneous position change of the pattern as well as the direction and speed of the golf ball measured at the time of hitting is analyzed and calculated by continuously photographing the pattern of the specific structure using a sensor such as a high speed camera installed in a screen golf course, thereby calculating the trajectory of the hit golf ball.

In general, in a case in which a golf game or practice is performed using screen golf, the speed of the golf ball after hitting is acquired by a speed sensor installed on the front or above a golfer, and the rotational speed of the golf ball is calculated by measuring the position change of the pattern for a specific period of time after photographing the pattern formed on the golf ball cover 30. Using the speed vector and the rotational speed data, the driving distance of the hit golf ball and the roll distance of the golf ball after falling are calculated by the simulator in consideration of wind speed and direction and grass conditions at the falling spot, and then, the result is displayed on a screen.

In order for the safety golf ball 100 for practice to be used in such a screen golf course, it is necessary that the trajectory of the ball measured and calculated by a measuring device after hitting must be calculated to be similar to the trajectory of the real golf ball. To this end, it is necessary for the golf ball 100 according to the present invention to maintain a specific ratio between a driving distance measured by hitting the golf ball 100 and a driving distance measured by hitting a real golf ball with various types of irons.

Hereinafter, configurations and effects of the present invention will be described in more detail with reference to specific embodiments. However, the embodiments are intended to describe the present invention in more detail, and the scope of the present invention is not limited to these embodiments.

Embodiment 1

The inner core 10 has a diameter of 25 mm, the outer core 20 has a thickness of 3 mm ranging from a first surrounding layer to a fifth surrounding layer, and the cover 30 is manufactured to have a thickness of 1 mm. A six-piece safety golf ball 100 for practice was formed to have hardness of 90, 80, 70, 60, and 50 from the inside by reducing the foaming ratio of the polyurethane sponge of the outer core 20, namely, air content per unit volume, at a fixed ratio for each layer. The golf ball 100 refers to as an embodiment 1.

Embodiment 2

The inner core 10 has a diameter of 25 mm, the outer core 20 has a thickness of 3 mm ranging from a first surrounding layer to a fifth surrounding layer, and the cover 30 is manufactured to have a thickness of 1 mm. A six-piece safety golf ball 100 for practice was formed to have hardness of 90, 75, 60, 55, and 50 from the inside by reducing the foaming ratio of the polyurethane sponge of the outer core 20, namely, air content per unit volume, at an unfixed ratio for each layer. The golf ball 100 refers to as an embodiment 2.

Experimental Example

Using a golf swing machine (RoboGolfPro) and a driving distance measuring system for a screen golf course, a golfer hit golf balls ten times with the same force (swing speed of 100 MPH) using No. 7, No. 8, and No. 9 irons, and then, the average driving distance was simulated. The results of experiments are shown in Table 1 and FIG. 3.

	TABLE 1
	Embodiment 1	Embodiment 2	Real golf ball
Driving	No. 7	115.4	110.8	130
distance	No. 8	106.2	94.6	120
(m)	No. 9	95.8	92.7	110
Standard deviation	3.8	7.1	1.3

As seen from Table 1 and FIG. 3, compared with the average driving distance obtained when a golfer hits the actual golf ball, an average driving distance of about 80-90% could be obtained. However, in the case of Embodiment 2, since the deviation of the measured value was too large, the reliability of the result was low. In addition, it was confirmed that the recovery speed was excellent in Embodiment 1.

Referring to FIG. 3, in the case of Embodiment 1, the driving distance was shown linearly according to types of irons, but in the case of Embodiment 2, the driving distance was shown nonlinearly by being influenced by types of irons and the measurement deviation.

When a golfer performs screen golf using the safety golf ball 100 for practice according to the present invention, a distance is calculated by multiplying a specific ratio by the driving distance calculated by the measured speed and rotation after the golfer hits the golf ball 100, so the driving distance almost similar to that obtained by hitting a real golf ball may be displayed on the screen, thereby obtaining a similar effect obtained when a golfer practices with the real golf ball.

In addition, the safety golf ball for practice according to the present invention can secure safety since the golf ball is soft due to hardness gradually reduced outward, reduce a damage by ball hitting, and allow even children to use it in safety.

The present specification describes several examples of various embodiments performed by the present invention, but the technical spirit of the present disclosure is not limited or restricted thereto, and may be modified in various ways by one of ordinary skill in the art.

Claims

1. A safety golf ball for practice comprising:

an inner core;

a soft outer core having hardness lower than that of the inner core; and

a cover positioned outside,

wherein the hardness of the outer core is gradually reduced outward.

2. The safety golf ball according to claim 1, wherein the outer core has three or more layers.

3. The safety golf ball according to claim 2, wherein the outer core is made of a material of a polyurethane sponge.

4. The safety golf ball according to claim 2, wherein hardness of the outer core decreases outward linearly.

5. The safety golf ball according to claim 1, wherein a rotation recognition pattern is formed on the cover.

6. The safety golf ball according to claim 5, wherein the rotation recognition pattern includes a mark including two or more bending structures, a mark in which two points and a straight line are combined, a mark in which three points are combined, or a portion of the shape of a QR code.

7. The safety golf ball according to claim 3, wherein hardness of the outer core decreases outward linearly.