Patent Publication Number: US-7588499-B2

Title: Putter head

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a putter head of a putter for golf, and in particular, to a putter head that is provided with a void space at its central part and a bar crossing the void space in a forward-backward direction. 
   2. Description of the Related Art 
   A putter head provided with a void space passing through the central part thereof in the thickness direction (vertical direction) and a bar crossing the void space in a forward-backward direction is disclosed in JP-A-2005-66249. By forming the void space, the moment of inertia about the gravity center is increased and the sweet area of the putter head is made larger. Further, a feeling of hitting sensation is improved by providing the bar crossing the void space in the forward-backward direction. 
   SUMMARY OF THE INVENTION 
   The putter head disclosed in JP-A-2005-66249 requires high dimensional accuracy in the structure because the bar is integrally formed with the putter head. Accordingly, it is an object of the invention to provide a putter head that can be easily manufactured. 
   According to JP-A-2005-66249, a shaft fixing hole is formed at the heel side. Thus, it is difficult to transmit a feeling of hitting sensation to a shaft. 
   It is another object of the invention to provide a putter head that can easily transmit a feeling of hitting sensation to a shaft. 
   According to a first aspect of the invention, a putter head includes a shaft fixing hole, a head main body that is provided with a void space, which is a through-hole vertically passing through the head main body at its central part or a concave portion recessed from a top surface of the head main body, and a bar that crosses the void space in a forward-backward direction. The head main body and bar are separate parts, the bar is inserted into a bar insertion hole extending from a front end surface or a rear end surface of the head main body in the forward-backward direction, and a cover is mounted on the head main body to close the bar insertion hole. 
   According to a second aspect of the invention, the shaft fixing hole is provided in the bar. 
   According to a third aspect of the invention, the shaft fixing hole is provided to pass through the bar from a top surface of the putter head. 
   According to a fourth aspect of the invention, a recess is formed in the front end surface of the putter head, the bar insertion hole is formed in a bottom wall of the recess, and a face member as a cover is mounted on the recess. 
   According to a fifth aspect of the invention, the recess is formed in the rear end surface of the putter head, the bar insertion hole is formed in a bottom wall of the recess, and a cover is mounted on the recess. 
   According to a sixth aspect of the invention, colors of the head main body and bar are different from each other. 
   According to a seventh aspect of the invention, a volume of the void space is in a range of 8000 to 100000 mm 3 . 
   According to an eighth aspect of the invention, a length of the bar inside the void space is in a range of 30 to 80 mm. 
   The putter head according to the aspects of the invention is easily manufactured because a head and bar are separately manufactured. 
   According to the aspects of the invention, the shaft fixing hole is provided in the bar, or is provided to pass through the head main body and the bar, so that a feeling of hitting sensation is easily transmitted to a shaft. In addition, the shaft is inserted into the head main body and bar and fixed thereto, and thus fixing strength of the bar increases. 
   According to the aspects of the invention, the recess is formed in the front end surface of the putter head, the bar insertion hole is formed in the bottom wall of the recess, and the cover, that is, the face member is mounted on the recess. Therefore, a feeling of hitting sensation is easily transmitted to the shaft. 
   According to the aspects of the invention, the recess is formed in the rear end surface of the putter head, the bar insertion hole is formed in the bottom wall of the recess, and the cover is mounted on the recess. Therefore, the putter head can be easily manufactured. 
   According to the aspects of the invention, the head main body and bar have different colors, so that the bar implicitly indicates a back swing direction and a rolling direction of a ball. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a putter head according to an embodiment of the invention; 
       FIGS. 2A and 2B  are a plan view and a side view of the putter head, respectively; 
       FIG. 3  is a front view of the putter head; 
       FIG. 4  is a bottom view of the putter head; 
       FIG. 5  is a rear view of the putter head; and 
       FIG. 6  is a cross-sectional view taken along line VI-VI of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An embodiment of the invention will now be described in detail with reference to  FIGS. 1 to 6 . 
     FIG. 1  is a perspective view of a putter head according to an embodiment of the invention.  FIG. 2A  is a plan view of the putter head.  FIG. 2B  is a left side view of the putter head.  FIG. 3  is a front view of the putter head.  FIG. 4  is a bottom view of the putter head.  FIG. 5  is a rear view of the putter head.  FIG. 6  is a cross-sectional view of the putter head taken along line VI-VI of  FIG. 3 . 
   A putter head  10  includes a head main body  20  that defines the outer periphery of the putter head, and a bar  40  that crosses a void space of the head main body  20  in a forward-backward direction. 
   The head main body  20  has a front portion  21 , a tow side portion  22 , a heel side portion  23 , and a back portion  24  where the tow and heel side portions  22  and  23  are joined. The tow side portion  22  extends backward from the tow of the front portion  21  to the center of the back portion  24  between the tow and heel sides of the putter head. The heel side portion  23  extends backward from the heel of the front portion  21  to the center of the putter head. Therefore, the head main body  20  substantially has a triangular frame shape in plan view. 
   In this embodiment, a substantially triangular void space  25  surrounded by the front portion  21 , the side portions  22  and  23 , and the back portion  41  is provided. The void space  25  passes through an upper surface and a lower surface of the head main body  20 . 
   As shown in  FIG. 6 , a recess  30  is formed in the front surface (face) of the head main body. The recess  30  occupies a main area of the face. The length of the recess  30  in the toe-heel direction is preferably 35 to 95 percent, and particularly, 45 to 90 percent of the length of the face in the toe-heel direction. Further, the vertical width of the recess  30  is preferably 70 to 98 percent, particularly, 75 to 95 percent of the width of the face in the vertical direction. The depth of the recess  30  is preferably 0.5 mm or more, for example, 2 to 6 mm. 
   A first insertion hole  31  passes through from a bottom wall  30   a  of the recess  30  to the void space  25 . A second insertion hole  32  is formed in the back portion  24  along the extension line of the first insertion hole  31 . The second insertion hole  32  is recessed from the inside of the void space  25 , but does not extend to a rear end surface of the head main body  20 . 
   The bar  40  is inserted into the insertion holes  31  and  32  and fixed thereto by an adhesive. In this embodiment, the bar  40  is configured to have a cylindrical solid body and its front end surface is flush with the bottom wall  30   a  of the recess  30 . 
   A face member  50  is attached to the recess  30 . The face member  50  may be formed of a material, such as synthetic resin, elastomer, rubber, metal, ceramics, carbon, or the like. 
   Preferably, the face member  50  is fixed by an adhesive. When the face member  50  is formed of a metal, the face member can be fixed by caulking, thermal insert, or cooling insert etc. 
   A shaft fixing hole  60  is provided in the putter head  10  to pass through the bar  40  from the top face of the front portion  21  of the head main body  20 . A shaft (not shown) is inserted into the shaft fixing hole  60  and fixed by adhesive. In this embodiment, the shaft fixing hole  60  passes through the bar  40 , but does not extend to the bottom of the head main body  20 , so as to form a concavity. The shaft fixing hole  60  has a diameter less than a diameter of the bar  40  and passes through the bar like a through-hole. The axis of the shaft fixing hole  60  is inclined toward the heel side as it goes upwards, and preferably crosses the axis of the bar  40 . 
   As shown in  FIG. 4 , at a plurality of positions of the bottom of the head main body  20 , weights  70  formed of a material with high specific gravity ranging from 7.8 to 12, such as stainless, tungsten, tungsten-nickel alloy, or the like, are fixed to the head main body  20  by screwing or caulking. Each of the weights  70  does not protrude from the bottom of the head main body  20 . 
   In this embodiment, the head main body  20  and the bar  40  are formed of an aluminum alloy, not including the weights  70 , with specific gravity of 2.7 to 2.8. Further, at least one of the outer surfaces of the head main body  20  and the bar  40  is anodized, which makes them to have different colors. In particular, it is preferable that the bar  40  is colored with a dark color, such as blue, and the head main body  20  is colored with a light color, such as silver, gray, or white. 
   According to the putter head having the above-described configuration, the head main body  20  and the bar  40  are separate parts and easily manufactured. Further, assembling of the putter head including the assembly of the head main body  20  and the bar  40  is simplified because the bar  40  is inserted into the first and second insertion holes  31  and  32  in sequence and the face member  50  is mounted thereafter. 
   In this embodiment, since the shaft fixing hole  60  is provided to pass through the head main body  20  and the bar  40 , a player can easily feel a hitting sensation through the shaft. 
   According to this embodiment, since the void space  25  is formed, the moment of inertia of the putter head increases and a hit ball stably rolls. The volume of the void space  25  (except for the bar  40 ) is preferably in a range of 8000 to 100000 mm 3 , and particularly, 15000 to 80000 mm 3 . 
   In this embodiment, because the bar  40  crosses the void space  25  in the forward-backward direction, a player can easily estimate a back swing direction and a rolling direction of a ball. In particular, a player effectively estimates the directions when the head main body  20  and the bar  40  have different colors. 
   It is preferable that the axis of the bar  40  has an angle ranging from 87 to 93°, and particularly, 90° with respect to the toe-heel direction of the face. 
   Preferably, the length of the bar  40  inside the void space  25  is in a range of 30 to 80 mm, and the diameter of the bar  40  is in a range of 10 to 13 mm. The diameter of the bar  40  is preferably larger than that of the shaft fixing hole  60  by 1 mm or more, e.g., in a range of 1 to 5 mm. 
   The bar  40  is a solid bar, but may be a hollow cylinder. The bar  40  may be an ellipse column, an ellipse hollow column, a square column or a square hollow column. 
   The length of the first insertion hole  31  (the length from the bottom wall  30   a  to the void space  25 ) is preferably in a range of 3 to 25 mm, particularly, 5 to 20 mm. The depth of the second insertion hole  32  is preferably 3 mm or more, for example, in a range of 3 to 10 mm. 
   The above-described embodiment is just an example of the invention, and the invention can include other configurations not shown in the drawings. For example, an insertion hole passing through a head main body from the rear end surface to a central hole may be formed, and a bar may be inserted into the insertion hole from the rear side. In addition, an opening of the insertion hole at the rear end may be closed by a closing means, such as a cap. The closing means may be fixed by a screw or an adhesive. An elastic body, such as rubber, may be interposed between the bar and the closing means. 
   In this case, an elastic body, such as rubber, may be interposed between the foremost end of the insertion hole and the bar. 
   The bar inserted in the insertion hole may be fixed by screwing. 
   Although the void space  25  is a through-hole that passes through the head main body in the thickness wise direction in the above-described embodiment, a hole may be recessed from the top surface and have a bottom.