Patent Publication Number: US-8979668-B2

Title: Putter-type golf club head and putter-type golf club

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a putter-type golf club head and a putter-type golf club capable of enhancing an impact feeling while keeping a rolling distance and direction high level. 
     2. Related Art 
     In recent years, a putter-type golf club head including a head main portion made of metal, and a face insert made of elastic material and arranged in a concave portion of the head main portion has been known. With such a putter-type golf club, soft impact feeling can be obtained. 
     Japanese Patent Application Publication No. H08-196668 proposes use of an elastomer as an elastic material for a face insert in order to make impact feeling of a putter softer. However, if a soft face insert is used, there is a fear that a launch direction of a golf ball may deviate in a subtle way (degradation of directionality) or undesirable, unnecessary spin may be generated. 
     In order to solve the defects described above, Japanese Patent Application Publication No. 2004-236985 proposes a face insert having a two-layer structure in which a relatively hard elastic material is used on a front side. However, with such a putter-type golf club head, soft impact feeling cannot be obtained. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in light of the actual circumstances described above, and an object of the present invention is to provide a putter-type golf club head and a putter-type golf club capable of obtaining good, soft impact feeling while keeping a rolling distance and directionality of a golf ball at a high level, by making a face insert a three-layer structure, and providing a relationship of hardness and a rebound resilience of each layer. 
     According to the present invention, a putter-type golf club head having a face on a front side to hit a golf ball comprises a head main portion provided with a concave portion on a side of the face, and a face insert made of elastic material attached to the concave portion of the head main portion, the face insert having a three-layer structure comprising of a first layer disposed at the front, a third layer disposed at the rear, and a second layer disposed between the first layer and the third layer, each of the first layer, the second layer, and the third layer having a hardness of h 1 , h 2 , and h 3  and a rebound resilience of r 1 , r 2 , and r 3 , and the first layer, the second layer, and the third layer satisfying the following relations:
 
 h 2&lt; h 1&lt;= h 3,
 
 r 1&gt; r 2,
 
and
 
 r 1&gt; r 3.
 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of a putter-type golf club head of this embodiment; 
         FIG. 2  is an exploded perspective view of a face insert thereof; 
         FIG. 3  is a front view of a putter-type golf club head; 
         FIG. 4  is a cross sectional view taken along X-X of  FIG. 3 ; 
         FIG. 5  is a cross sectional view taken along Y-Y of  FIG. 3 ; 
         FIG. 6A  to  FIG. 6   c  are cross sectional views illustrating a method for manufacturing a face insert; and 
         FIG. 7  is a diagrammatic view showing the way of an actual hitting test. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An embodiment of the present invention will be described hereinafter on the basis of the drawings. 
     As shown in  FIG. 1 , a putter-type golf club head (hereinafter simply referred to as a “putter head”)  1  of the embodiment has a face  2  to hit a golf ball on a front side. 
     The face  2  is a plain surface, and configured to have an almost horizontally long, rectangular shape which is long in toe T and heel H direction (horizontal direction). In addition, the face  2  is inclined with a small loft angle from 1 to 3 degrees, for example. 
     The putter head  1  includes a head main portion  1 A provided with a concave portion  3  on a side of the face  2  (front side), and a face insert  1 B made of elastic material attached to the concave portion  3  of the head main portion  1 A. 
     The head main portion  1 A is preferably made of metallic materials such as an aluminum alloy, stainless, titanium, or soft iron, and is formed of an almost block shape which extends backwardly from an upper edge, a lower edge, a toe side edge, and a heel side edge of the face  2 . The head main portion  1 A is manufactured by various methods such as casting, forging or cut-out. In addition, for example, a lower end of a club shaft S is firmly fixed to a top surface of the head main portion  1 A. 
     The concave portion  3  is formed across main parts of the face  2  in a toe-heel direction and an up-down direction, and has an annular inner circumferential surface  3   a  which delimits a contour of the concave portion  3  and a bottom surface  3   b  which closes the inner circumferential surface  3   a  on the head interior side. Such a concave portion  3  forms a bottomed space which sags from the face  2 . Although the concave portion  3  of the embodiment is formed like a rectangular shape which is horizontally long in the toe-heel direction almost following a contour of the face  2 , it should not be limited to such an aspect. In addition, an annually continuing front surface marginal part  4  is formed on a front surface of the head main portion  1 A and around the concave portion  3 . 
     The face insert  1 B is formed like a block having a front surface  5  exposed to and disposed on the side of the face  2 , a back surface  7  which is a face opposite thereto, and an outer circumferential surface  6  which continues and annually extends between the front surface  5  and the back surface  7 . The face insert  1 B has the back surface  7  face the bottom surface  3   b  of the concave portion  3  and the outer circumferential surface  6  face the inner circumferential surface  3  of the concave portion  3 , and is disposed in a close relation in a preferred embodiment. Then, by attaching the face insert  1 B to the concave portion  3  of the head main portion  1 A, the front surface  5  of the face insert  1 B and the front surface marginal part  4  of the head main portion  1 A form a substantially single plain surface, thereby forming the face  2 . In addition, the face insert  1 B is firmly fixed to the concave portion  3  of the head main portion  1 A by means of a double-sided tape or an adhesive and the like. 
     As shown in  FIG. 2  in an exploded manner, the face insert  1 B has a three-layer structure including a first layer  8  disposed at the front, a third layer  10  disposed at the rear, and a second layer  9  disposed between the first layer  8  and the third layer  10 . Then, the present invention is characterized in that when the first layer  8 , the second layer  9 , and the third layer  10  have hardness of h 1 , h 2 , and h 3 , and a rebound resilience of r 1 , r 2 , and r 3 , respectively, they satisfy the following relations:
 
 h 2&lt; h 1&lt;= h 3
 
 r 1&gt; r 2
 
 r 1&gt; r 3.
 
     More specifically, as a result of various experiments, the inventor et. al found that it is possible to strike a balance of obtaining soft impact feeling and keeping a rolling distance and direction of a golf ball at a high level, by satisfying a relationship of the following three conditions: 
     (a) Make the hardness of the second layer  9  the smallest. 
     (b) Make the hardness of the third layer  10  greater than the hardness of the first layer  8 . 
     (c) Make the rebound resilience of the first layer  8  greater than the rebound resilience of the second layer  9  and the third layer  10 . 
     More specifically, the present invention can achieve soft impact feeling as well, while keeping a rolling distance and direction of a golf ball at a high level, by simultaneously satisfying the three conditions of (a) to (c) above. In addition, measurements are made with each hardness h 1 , h 2 , and h 3  as shore D hardness. 
     Above all, satisfying the conditions (a) and (b), i.e., by making the second layer  9 , which is positioned at the center, the softest, and by making the first layer  8  and the third layer  10 , which are positioned before and after it, relatively harder, deflection of the face insert when a golf ball is hit is moderately controlled, while good impact feeling is still maintained. In addition, by making the rebound resilience of the first layer  8 , which comes into direct contact with a golf ball, the greatest by the condition (c), not only directional stability of a golf ball can be improved but also rolling of a golf ball is improved, while preventing generation of unnecessary spin by accelerating so-called letting go of a ball when the ball is hit. On the other hand, as the second layer and the third layer which have small rebound resilience have great vibrational absorption effect, they are useful in absorbing uncomfortable vibration and maintaining good impact feeling. These actions will be revealed in embodiments to be described below. 
     As elastic material to be used in respective layers  8  to  10  of the face insert  1 B, an ionomer resin, a urethane resin, a synthetic resin of a urethane elastomer, a polyester elastomer, or a polyamide elastomer and the like, or a rubber elastic body such as a styrene-butadiene rubber or a butadiene rubber is preferred. 
     It is desirable that the Sore D hardness h 1  of the first layer  8  is 40° to 70°. More specifically, if the hardness h 1  is less than 40°, deflection of the face insert  1 B when a golf ball is hit increases, and directionality of the golf ball tends to degrade. In contrast, when the hardness h 1  exceeds 70°, it may not be possible to achieve soft impact feeling. Above all, it is desirable that the hardness h 1  of the first layer  8  is more preferably 45° or more and even more preferably 50° or more, or more preferably 65° or less and even more preferably 60° or less. 
     Now, the shore D hardness of the elastic material conforms to the provision in “ASTM-D 2240-68”, and is measured by an automatic rubber hardness tester (Product name “P1” of Kobunshi Keiki Co., Ltd.) provided with a shore D type hardness tester. In measurements, 2-mm thick sheets fabricated of the same material as the layers of the face insert are used. Prior to a measurement, the sheets are stored in the temperature of 23° C. for two weeks, and three sheets are superposed when a measurement is performed. 
     It is desirable that the rebound resilience r 1  of the first layer  8  is 50% to 80%. When the rebound resilience r 1  is less than 50%, rolling of a golf ball may degrade. In contrast, when the rebound resilience r 1  exceeds 80%, not only the rolling of a golf ball excessively improves, but also uncomfortable vibration tends to be transmitted to hands of a golf player. Above all, it is desirable that the rebound resilience r 1  is more preferably 55% or more and even more preferably 60% or more, or more preferably 75% or less and even more preferably 70% or less. 
     The rebound resilience conforms to the provision in “JIS K 6255”, and is obtained by a Lupke rebound resilience test (test temperature and humidity of 23° C., 50 RH %). A disk shaped slab which is molded by a hot press and has a thickness of 2 mm and a diameter of 28 mm is used in measurements. In a measurement, six slabs are superposed. Slabs comprising the same composition as elastic material of each layer of the face insert is used in measurements. In addition, slabs are stored in advance in the temperature of 23° C. for two weeks. 
     As shown in  FIG. 4  which is a cross sectional view taken along x-x in  FIG. 3 , it is desirable that a thickness D 1  of the first layer  8  is preferably set from 0.3 to 3.0 mm. When the thickness D 1  is small, it may not be possible to obtain sufficiently soft impact feeling. In contrast, when the thickness D 1  is great, a deflecting part increases, and thus directionality of a golf ball may degrade. Above all, it is desirable that the thickness D 1  is more preferably 0.5 mm or more and even more preferably 0.8 mm or more, or more preferably 2.8 mm or less and even more preferably 2.5 mm or less. 
     In addition, if thickness of each layer of the face insert  1 B is not constant, thickness of a central area in a toe-heel direction, which is in direct or indirect contact with a golf ball most frequently, is made smallest. 
     As described above, although the Shore D hardness h 2  of the second layer  9  is preferably set smaller than the hardness h 1  of the first layer  8  and the hardness h 3  of the third layer  10 , it is desirable that the hardness h 2  is preferably in a range of from 30 to 60°. When the hardness h 2  is less than 30°, deflection of the first layer  8  when a golf ball is hit cannot be controlled, and thus directionality of the golf ball may degrade. In contrast, when the hardness h 2  exceeds 60°, it may not be possible to obtain soft impact feeling. Above all, it is desirable that the shore D hardness h 2  of the second layer  9  is more preferably 35° or more and even more preferably 40° or more, or more preferably 55° or less and even more preferably 50° or less. 
     It is desirable that the rebound resilience r 2  of the second layer  9  is preferably set in a range of from 20 to 50%. When the rebound resilience r 2  is less than 20%, deflection of the face insert when a golf ball is hit becomes too great, which makes it difficult to transmit impact feeling to hands of a golf player, who thus finds it difficult to gain a sense of distance. In contrast, when the rebound resilience r 2  is more than 50%, uncomfortable vibration when a golf ball is hit may be transmitted to hands of a golf player. Above all, it is desirable that the rebound resilience r 2  of the second layer  9  is more preferably 25% or more and even more preferably 30% or more, or more preferably 45% or less and even more preferably 40% or less. 
     It is good if a thickness D 2  of the second layer  9  is 0.6 to 5.0 mm. When the thickness D 2  falls below 0.6 mm, it may not be possible to obtain soft impact feeling. In contrast, when the thickness D 2  exceeds 5.0 mm, deflection of the first layer  8  cannot be controlled, and directionality of a golf ball may degrade. Above all, it is desirable that the thickness D 2  of the second layer  9  is more preferably 0.8 mm or more and even more preferably 1.0 mm or more, or more preferably 4.8 mm or less and even more preferably 4.6 mm or less. Then, in particular, it is desirable that the thickness D 2  is 20 to 35% of the entire thickness D of the face insert  1 B. 
     It is desirable that the shore D hardness h 3  of the third layer  10  is preferably set in a range of from 40 to 70°. When the hardness h 3  is less than 40°, deflection of the face insert  1 B when a golf ball is hit increases, and thus directionality of a golf ball may degrade. In contrast, when the hardness h 3  exceeds 70°, it may not be possible to obtain soft impact feeling. Above all, it is desirable that the shore D hardness h 3  of the third layer  10  is more preferably 45° or more and even more preferably 50° or more, or more preferably 65° or less and even more preferably 60° or less. 
     It is desirable that the rebound resilience r 3  of the third layer  10  is set in a range of from 20 to 50%. When the rebound resilience r 3  is less than 20%, deflection of the face insert  1 B increases, which makes it difficult to transmit impact feeling to hands of a golf player, who thus finds it difficult to gain a sense of distance. In contrast, if the rebound resilience exceeds 50%, vibration when a golf ball is hit may not be absorbed sufficiently. Above all, it is desirable that the rebound resilience r 3  is more preferably 25% or more and even more preferably 30% or more, or more preferably 45% or less and even more preferably 40% or less. 
     It is desirable that a thickness D 3  of the third layer  10  is set in a range of from 0.5 to 8.0 mm. When the thickness D 3  is less than 0.5 mm, it may not be possible to obtain soft impact feeling. In contrast, when the thickness D 3  exceeds 8.0 mm, a deflecting part when a golf ball is hit increases, and impact feeling may become significantly softer. Above all, it is desirable that the thickness D 3  of the third layer  10  is more preferably 0.7 mm or more and even more preferably 1.0 mm or more, or more preferably 7.5 mm or less and even more preferably 7.0 mm or less. 
     In addition, as is obvious from  FIG. 2  and  FIG. 3 , the first layer  8  of the face insert  1 B of the embodiment includes a plate portion  8 A extending from a toe side to a heel side of the face and a plurality of projections  11  extending backwardly from the rear of the plate portion  8 A. In addition, the thickness D 1  is a thickness at a position where the projections  11  are removed. 
     In the embodiment, the projections  11  include short projections  11   a  and long projections  11   b  which are longer than the short projections  11   a.    
     As is obvious from  FIG. 3  and  FIG. 5 , the short projections  11   a  of the embodiment include a plurality of projections (5 projections each in this example) which are each intermittently arranged in the toe-heel direction on the side of the upper edge and the lower edge of the rear of the first layer  8 . A length L 1  of the short projections  11   a  is formed to be substantially equal to the thickness D 2  of the second layer  9 . 
     In addition, as is obvious from  FIG. 3 , the long projections  11   b  in the embodiment include a plurality of projections (4 projections each in this example) which are intermittently arranged in the toe-heel direction in the almost central area of the up-down direction of the rear of the first layer  8 . A length L 2  of the long projections  11   b  is formed to be substantially equal to a sum (D 2 +D 3 ) of the thickness D 2  of the second layer  9  and the thickness D 3  of the third layer  10 . 
     As shown in  FIG. 2 , the second layer  9  of the embodiment includes a plate portion  9   a , and a flange  9   b  which protrudes forward from a front surface of the plate portion  9   a  and continuously covers an outer circumferential surface of the plate portion  8 A of the first layer  8 . Such a second layer  9  is preferable in that it absorbs and damps vibration components in many directions, including vibration in the up-down and toe-heel directions as well as vibration in a front-back direction of the first layer  8 . 
     In addition, on the plate portion  9   a  of the second layer  9  are formed a plurality of holes  13  including through holes in which projections  11  (the short projections  11   a  and the long projections  11   b ) are inserted. Then, through insertion of respective projections  11   a ,  11   b  into the holes  13 , the first layer  8  and the second layer  9  are strongly and integrally joined. 
     The third layer  10  of the embodiment includes a plate portion  10   a , a toe-side flange  10   b  which protrudes forward from the front surface of the plate portion  10   a  and from the toe T side and covers an outer circumferential surface of the second layer  9 , and a heel-side flange  10   c  which protrudes forward from the front surface of the plate portion  10   a  and from the heel H side and covers the outer circumferential surface of the second layer  9 . Such a third layer  10  is also preferable in that it absorbs and damps vibration components in many directions, including vibration in the toe-heel direction of the first layer  8  and the second layer  9 . 
     In addition, on the plate portion  10   a  of the third layer  10  are formed a plurality of holes  14  into which only the long projections  11   b  are inserted. Then, through insertion of the long protrusions  11  of the firs layer  8  into the holes  14 , the first layer  8 , the second layer  9 , and the third layer  10  are strongly and integrally joined. 
     As shown in  FIG. 5 , while the long protrusions  11   b  arranged in the central part of the face insert  1 B in the up-down direction abut against the bottom surface  3   b  of the head main portion  3  made of metallic materials, the short protrusions  11   a  are in contact with the front surface of the third layer  10 . Such a face insert  1 B can make an entire apparent rebound resilience when a ball is hit with the upper edge side B or the lower edge side c smaller than when a ball is hit with the central area A, which is a preferred hit position, in the up-down direction. Thus, impact absorption performance can be improved by reserving great deflection when a ball is hit with the upper edge side B or the lower edge side C, which are clearly hit positions of mishits. 
       FIG. 6  shows one embodiment of a method for manufacturing a face insert. 
     In the embodiment, as shown in  FIG. 6A , first of all, the first layer  8  having the projections  11  are fabricated by, for example, injection molding and the like. 
     Then, as shown in  FIG. 6B , the first layer  8  is set in a first mold M 1 . The first mold M 1  includes a lower mold Ma on which the first layer  8  is placed and an upper mold Mb which covers the lower mold Ma, and on the upper mold Mb are provided holes H into which the long projections  11  can be inserted. Then, a cavity c 1  for forming the second layer  9  around the first layer  8  is formed, by aligning the holes H with the long projections  11   b  of the first layer  8  placed on the lower mold Ma and then closing the upper mold Mb. Then, composition forming the second layer  9  is injected into the cavity C 1 . This enables an integral mold  20  of the first layer  8  and the second layer  9  to be obtained in the first mold M 1 . 
     Next, as shown in  FIG. 6C , the integral mold  20  of the first layer  8  and the second layer  9  is set in a second mold M 2 . The second mold M 2  includes, for example, the lower mold Ma on which the integral mold  20  is placed and an upper mold Mc which covers the lower mold Ma, and on the upper mold Mc are also provided holes H into which the long projections  11  can be inserted. Then, a cavity c 2  for forming the third layer  10  around the integral mold  20  is formed by aligning the holes H with the long projections  11   b  of the integral mold  20  placed on the lower mold ma and closing the upper mold Mc. Then, composition forming the third layer  10  is injected into the cavity c 2 . This enables the face insert  1 B, which is an integral mold of the first layer  8 , the second layer  9 , and the third layer  10 , to be obtained in the second mold M 2 . 
     Since with the manufacturing method described above, positioning of a mold (the upper molds Mb and Mc) can be easily done relative to the projections  11  of the first layer  8 , the face insert  1 B can be molded precisely. 
     [Comparison Test] 
     To check the effect of the present invention, a putter-type golf club whose total length was 34 inches was manufactured experimentally by attaching a shaft to a putter-type golf club head having the basic configuration as shown in  FIG. 1 , and an actual hit test thereof was performed. A head main portion was a casting of SUS630. A face insert had a basic configuration shown in  FIG. 2 , a thickness of a flange unit of a second layer was 1 mm, and a thickness of a maximum part of a flange unit of a third layer was 2 mm. 
     Actual tests were performed by 10 golfers repeating putting of 6 m five times, using commercially available 3 piece golf balls (Z-UR) made by SRI Sports Limited. Then, for impact feeling, degree of hardness when each golfer putts and vibration transmitted to hands were evaluated based on feeling and with the following criteria, and all averages were considered results. They show that the greater a numeric value is, the better impact feeling is. 
     &lt;Impact Feeling (Hardness)&gt; 
     5 points . . . very soft 
     4 points . . . Soft 
     3 points . . . common (on the basis of the comparative example 1) 
     2 points . . . Hard 
     1 point . . . very hard 
     &lt;Impact Feeling (Vibration)&gt; 
     5 points . . . vibration transmitted to hands is very small. 
     4 points . . . vibration transmitted to hands is small. 
     3 points . . . Common (on the basis of the Comparative example 1) 
     2 points . . . vibration transmitted to hands is large. 
     1 point . . . vibration transmitted to hands is very large. 
     As shown in  FIG. 7 , horizontal deviation b from a vertical line N that connects a ball launch position P 1  and a target position P 2  to a ball stop position P 3 , and vertical deviation a from a horizontal line M that passes through the target position P 2  and is orthogonal to the vertical line N to the ball stop position P 3  were measured. Average horizontal deviation and average vertical deviation, which were averages of respective horizontal deviation b and vertical deviation a of the 10 golfers, were calculated, and evaluation was shown by indices with the Comparative example 1 as 1. This means that the greater a numeric value is, the greater deviation is and the worse the performance is. Test results and the like are shown in Table 1. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Com- 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 Com- 
               
               
                   
                 parative 
                   
                   
                   
                   
                   
                   
                 Com- 
                   
                   
                   
                   
                 Com- 
                 parative 
               
               
                   
                 Exam- 
                 Comparative 
                 Comparative 
                 Comparative 
                 Comparative 
                   
                 Exam- 
                 parative 
                 Exam- 
                 Comparative 
                 Comparative 
                 Exam- 
                 parative 
                 Exam- 
               
               
                   
                 ple 1 
                 Example 2 
                 Example 3 
                 Example 4 
                 Example 5 
                 Example 1 
                 ple 2 
                 Example 6 
                 ple 3 
                 Example 7 
                 Example 8 
                 ple 4 
                 Example 9 
                 ple 10 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 Number of Layers of 
                 1 
                 2 
                 2 
                 2 
                 2 
                 3 
                 3 
                 3 
                 3 
                 3 
                 3 
                 3 
                 3 
                 3 
               
               
                   
                 Face Insert 
               
               
                 First 
                 Material 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 TPU 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 PEBAX 
               
               
                 layer 
                 Hardness h1 (Shore D) 
                 55 
                 55 
                 40 
                 55 
                 55 
                 55 
                 63 
                 35 
                 55 
                 55 
                 55 
                 55 
                 55 
                 55 
               
               
                   
                 Rebound Resilience r1 
                 59 
                 59 
                 63 
                 35 
                 59 
                 59 
                 56 
                 70 
                 59 
                 59 
                 59 
                 59 
                 59 
                 59 
               
               
                   
                 (%) 
               
               
                   
                 Thickness D1 (mm) 
                 6 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
               
               
                 Second 
                 Material 
                 — 
                 PEBAX 
                 PEBAX 
                 PEBAX 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
                 PEBAX 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
               
               
                 layer 
                 Hardness h2 (Shore D) 
                 — 
                 63 
                 63 
                 63 
                 45 
                 45 
                 45 
                 45 
                 40 
                 40 
                 65 
                 45 
                 45 
                 45 
               
               
                   
                 Rebound Resilience r2 
                 — 
                 56 
                 56 
                 56 
                 30 
                 30 
                 30 
                 30 
                 40 
                 63 
                 40 
                 30 
                 30 
                 30 
               
               
                   
                 (%) 
               
               
                   
                 Thickness D2 (mm) 
                 — 
                 4 
                 4 
                 4 
                 4 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
               
               
                 Third 
                 Material 
                 — 
                 — 
                 — 
                 — 
                 — 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
                 TPU 
                 PEBAX 
                 TPU 
               
               
                 layer 
                 Hardness h3 (Shore D) 
                 — 
                 — 
                 — 
                 — 
                 — 
                 55 
                 55 
                 55 
                 55 
                 55 
                 55 
                 65 
                 55 
                 40 
               
               
                   
                 Rebound Resilience r3 
                 — 
                 — 
                 — 
                 — 
                 — 
                 35 
                 35 
                 35 
                 35 
                 35 
                 35 
                 40 
                 59 
                 40 
               
               
                   
                 (%) 
               
               
                   
                 Thickness D3 (mm) 
                 — 
                 — 
                 — 
                 — 
                 — 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
                 2 
               
               
                 Test 
                 Impact Feeling 
                 3.0 
                 2.8 
                 3.5 
                 3.0 
                 4.5 
                 4.4 
                 4.1 
                 4.6 
                 4.4 
                 4.0 
                 3.2 
                 4.2 
                 3.9 
                 4.5 
               
               
                 result 
                 (Hardness) 
               
               
                   
                 Impact Feeling 
                 3.0 
                 3.0 
                 2.2 
                 3.5 
                 4.2 
                 4.1 
                 4.1 
                 3.7 
                 4.0 
                 2.8 
                 3.6 
                 4.1 
                 2.9 
                 4.1 
               
               
                   
                 (Vibration) 
               
               
                   
                 Sum of Evaluation of 
                 6.0 
                 5.8 
                 5.7 
                 6.5 
                 8.7 
                 8.5 
                 8.2 
                 8.3 
                 8.4 
                 6.8 
                 6.8 
                 8.3 
                 6.8 
                 8.6 
               
               
                   
                 Impact Feeling 
               
               
                   
                 Vertical Deviation 
                 1.0 
                 0.7 
                 1.0 
                 1.5 
                 1.2 
                 0.7 
                 0.6 
                 1.2 
                 0.7 
                 0.8 
                 0.7 
                 0.6 
                 0.7 
                 1.3 
               
               
                   
                 Index 
               
               
                   
                 Horizontal Deviation 
                 1.0 
                 0.5 
                 1.1 
                 1.1 
                 1.6 
                 0.6 
                 0.5 
                 1.1 
                 0.8 
                 0.7 
                 0.7 
                 0.6 
                 0.7 
                 1.7 
               
               
                   
                 Index 
               
               
                   
                 Sum of Deviation 
                 2.0 
                 1.2 
                 2.1 
                 2.6 
                 2.8 
                 1.3 
                 1.1 
                 2.3 
                 1.5 
                 1.5 
                 1.4 
                 1.2 
                 1.4 
                 3.0 
               
               
                   
                 Indices 
               
               
                   
                 Remarks about 
                   
                 If a hard 
                 If a first layer 
                 When a 
                 If a second layer 
                 Thinning a 
                   
                 If the first 
                   
                 If a second 
                 When a 
                   
                 When a 
               
               
                   
                 Performance 
                   
                 second layer 
                 is made soft, 
                 rebound 
                 which is soft and 
                 second 
                   
                 layer is 
                   
                 layer which is 
                 second layer 
                   
                 third 
               
               
                   
                 Evaluation 
                   
                 is included, 
                 impact feeling 
                 resilience of 
                 has low rebound 
                 layer and 
                   
                 too soft, 
                   
                 soft but has 
                 has low 
                   
                 layer 
               
               
                   
                   
                   
                 directionality 
                 is improved. 
                 a first layer 
                 is included, 
                 adding a 
                   
                 horizontal 
                   
                 high rebound 
                 rebound but 
                   
                 has high 
               
               
                   
                   
                   
                 improves. 
                 However, the 
                 is low, rolling 
                 impact feeling 
                 third layer 
                   
                 deviation 
                   
                 is included, 
                 is hard, a 
                   
                 rebound, 
               
               
                   
                   
                   
                 However, 
                 improvement is 
                 degrades, 
                 improves. 
                 improve 
                   
                 increases. 
                   
                 adequate 
                 golfer does 
                   
                 vibration 
               
               
                   
                   
                   
                 impact 
                 not enough, 
                 and a sense 
                 However, if 
                 directionality 
                   
                   
                   
                 effect on 
                 not sense 
                   
                 absorption 
               
               
                   
                   
                   
                 feeling 
                 and 
                 of vertical 
                 thickness is 
                 without 
                   
                   
                   
                 impact feeling 
                 soft impact 
                   
                 is little 
               
               
                   
                   
                   
                 becomes 
                 directionality 
                 distance 
                 great, 
                 obstructing 
                   
                   
                   
                 cannot be 
                 feeling. 
                   
                 and 
               
               
                   
                   
                   
                 harder. 
                 also degrades. 
                 deteriorates. 
                 directionality 
                 impact 
                   
                   
                   
                 achieved. 
                   
                   
                 impact 
               
               
                   
                   
                   
                   
                   
                   
                 degrades. 
                 feeling. 
                   
                   
                   
                   
                   
                   
                 feeling 
               
               
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
                 is bad. 
               
               
                   
               
            
           
         
       
     
     In addition, symbols of materials of the face insert in Table 1 are as follows: 
     PEBAX: Polyether block amide (manufacturer: Arkema Inc.) 
     TPU: Thermoplastic urethane resin (Product name: Elastollan 11TYPE, made by BASF Corporation) 
     As a result of testing, it was confirmed that the putter-type golf club of the embodiment had small deviation, and kept a rolling distance or direction of a golf ball at a high level. In addition, good result was also obtained for impact feeling.