JPH0244774Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a wood club head structure for golf that is made from wood such as persimmon (persimmon tree), and by embedding a plurality of rod-shaped reinforcing materials inside the head body, the elastic modulus in a specific direction according to the wood grain can be improved. This prevents a decrease in shear rigidity, increases the bending rigidity due to impact when hitting the ball, suppresses loss of kinetic energy transmitted to the ball, and improves repulsion characteristics and batted ball sound. Generally, when this type of club head is cut from raw wood, the head is cut so that the face of the head body is facing forward, as illustrated in FIG. However, the material properties of such a club head exhibit anisotropy in the wood grain direction L, the radial direction R of the annual rings, and the tangential direction T of the annual rings, and the elastic modulus E _L , E _R , and E _T in each direction are different from that of Persimmon. In this case, the values are as shown in Table 1,

[Table] Also, the shear stiffness G _LR , G _LT , and G _RT for the forces acting in each direction are as shown in Table 2.

In particular, the elastic modulus E _T in the tangential direction T of the annual ring, which corresponds to the direction of ball hitting, and the elastic modulus E Shear stiffness against applied force
Since G _RT is very low compared to other directions, the impact when hitting the ball causes elastic deformation as shown by the two-dot dashed line in Figure 2, and the bending vibration as the natural vibration of the entire head is This occurs in the low frequency range of 2500 Hz, and as a result, not only does the sound of the ball being hit be bad, but the natural vibration of the entire head is excited by the impact when the ball is hit, and the kinetic energy transferred to the ball is equal to the energy expended in that vibration. This caused a decrease in the flight distance of the ball. This invention was aimed at solving the above-mentioned drawbacks of the conventional wooden wooden club, and its gist is that at least two or more rod-shaped reinforcing members are installed inside the wooden club head. By embedding and gluing parallel to the surface, the bending rigidity of the head in the direction of ball hitting is increased by utilizing the structural reinforcement effect of the sanderchch due to the interposition of rod-shaped reinforcing materials, and the natural vibration of the entire head due to the impact when hitting the ball is suppressed. Or, it is characterized by increasing the natural frequency to an extent that does not cause any harm to the ball, thereby improving the sound of the ball. Incidentally, since the face surface of the club head is usually formed in a convex circularly curved shape, it is sufficient that the rod-shaped reinforcing material is parallel to the tangent line or tangential surface at any point on the curved surface. Next, this invention will be explained based on the embodiment shown in FIG. 3 and subsequent figures. 3 to 5 show a first embodiment of this invention, and in the figures 1 is the head body of a wood club made of wood such as persimmon. Inside the head body 1, two cylindrical reinforcing members 2, 2' are embedded and glued parallel to the face surface 1a, spaced apart from each other in the ball hitting direction, and each reinforcing material is The buried position of 2 and 2' is
It is located along the central axis a-a passing through the sweet spot A of the face surface 1a parallel to the sole surface 1b. At this time, there are two or more reinforcing members 2 buried inside the head body 1, and by installing them apart from each other, the reinforcing effect on the head main body is only due to the stiffness of the reinforcing members alone. First, since a sanderch structure is formed in the ball hitting direction by the plurality of reinforcing members spaced apart from each other and the wood present between them, the reinforcing effect of the sanderch structure can also be obtained. By the way, the reinforcing materials 2 and 2' are made of lightweight and highly rigid FRP that uses carbon fiber, aramid fiber, boron fiber, etc. as reinforcing fibers and epoxy resin as a matrix resin, and the fiber direction is the longitudinal direction of the reinforcing material. The elastic modulus oriented in the direction is 1.3×10 ¹² dyn/cm ² (preferably 5.0×10 ¹² dyn/cm 2
cm ² or more), length 50 mm, diameter 7 mm (preferably 70% of the length L in the width direction of the face shown in Figure 3)
It consists of a cylindrical rod with a length of 3 mm or more and a diameter of 3 mm or more), and the buried position is 10 mm deep from the center point P of the face surface, preferably 20 mm or less from the center point P of the face surface. The other side is adhesively fixed at a position 20 mm closer to the face surface from the center point Q of the back surface 1c, preferably 30 mm or less from the center point Q of the back surface 1c, at the same height from the sole surface 1b. FIG. 6 shows a second embodiment of this invention, in which a face surface 1a buried in the head body 1 is shown.
Connect two rod-shaped reinforcing members 2, 2' parallel to the neck part 1.
It has a structure in which it is arranged in a direction perpendicular to the shaft axis b--b which is inserted and fixed in the shaft d so that a part of the longitudinal direction thereof corresponds to the sweet spot A. In addition, in this invention described above, the two rod-shaped reinforcing members embedded in the head body were arranged in a direction parallel to the sole surface or perpendicular to the shaft axis, but it is also possible to arrange them in a direction intermediate between these two. However, the function and effect of this invention can be exhibited in the same way. As explained above, this invention has multiple rod-shaped reinforcing materials embedded in the wooden head body parallel to the face surface and spaced apart from each other, which increases the bending rigidity of the head body in the direction of ball hitting. , it is possible to prevent the natural vibration mode of the entire head from being excited by the impact at the time of hitting the ball, as in the past, and thereby prevent a decrease in the kinetic energy transmitted to the ball, increasing the flight distance of the ball, It also has excellent practical effects, such as improving the sound of the ball being hit.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing how a wood club head is cut from wood; Fig. 2 is an explanatory diagram showing the bending vibration state of a conventional wooden club head when hitting a ball;
FIG. 3 is a plan view showing the first embodiment of the wood club head according to this invention, and FIG. 4 is a front view as well.
FIG. 5 is a longitudinal sectional side view taken along the line V-V in FIG. 4, and FIG. 6 is a front view showing a second embodiment of this invention.
It is. 1...Head body, 1a...Face surface, 1b
... Sole surface, 1c ... Back surface, 1d ... Neck part, 2, 2' ... Rod-shaped reinforcement material, A ... Sweet spot.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A wood club head for golf in which two or more rod-shaped reinforcing members are embedded inside the wooden club head parallel to the face surface. (2) The wood club head for golf according to claim 1 of the utility model registration, characterized in that each of the rod-shaped reinforcing members is arranged parallel to the sole surface. (3) Utility Model Registration Claim 1. The wood club head for golf according to claim 1, characterized in that each of the rod-shaped reinforcing members is disposed in a direction perpendicular to the shaft axis direction.