Method for manufacturing golf club head

Abstract

A method for manufacturing a hollow golf club head is disclosed, wherein a metallic main frame provided with a top opening and a bottom opening, a metallic crown plate and a metallic sole plate are prepared. The sole plate is placed in the bottom opening. A die is inserted into the inside of the main frame through the top opening. A protrusion of the sole plate is crushed onto the edge portion of the main frame around the bottom opening, by the use of the inserted die. Then the top opening is closed by the crown plate. The specific gravity SGm and proof stress YSm of the main frame, the specific gravity SGs and proof stress YSs of the sole plate, and the specific gravity SGf of the face plate satisfy: SGf=

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a wood-type hollow golf club head as an embodiment of the present invention.

FIG. 2 is a cross sectional view thereof.

FIG. 3 is a perspective view of a wood-type hollow golf club head as another embodiment of the present invention.

FIG. 4 is a cross sectional view of the second embodiment shown in FIG. 3.

FIG. 5 is a top view of the second embodiment.

FIG. 6 is a bottom view of the second embodiment.

FIG. 7 is an exploded perspective view showing the main frame, crown plate, face plate and sole plate of the second embodiment.

FIGS. 8 and 9 are enlarged cross sectional views for explaining a process of forming a top opening.

FIGS. 10, 11 and 12 are enlarged cross sectional views for explaining a process of fixing the crown plate to the main frame.

FIGS. 13, 14 and 15 are cross sectional views for explaining a process of fixing the sole plate to the main frame.

Claims

1. A method for manufacturing a hollow golf club head comprising the steps of: preparing a main frame made of a metal material and provided with a top opening and a bottom opening;preparing a sole plate made of a metal material, wherein the specific gravity SGs of the metal material of the sole plate is larger than the specific gravity SGm of the metal material of the main frame, andthe proof stress YSs of the metal material of the sole plate is smaller than the proof stress YSm of the metal material of the main frame, andthe sole plate comprises a main part which can almost fit to the bottom opening, and a protrusion which protrudes from the peripheral edge of an inner surface of the main part;placing the sole plate in the bottom opening of the main frame so that the protrusion protrudes from the inner surface of an edge portion of the main frame around the bottom opening;inserting a die into the inside of the main frame through the top opening;caulking the sole plate by crushing the protrusion of the sole plate onto said edge portion around the bottom opening, by the use of the inserted die;placing the crown plate in the top opening of the main frame; andfixing the crown plate to the main frame.

2. The method according to claim 1, which further comprises a step of soldering the sole plate and the main frame along their boundary on the outer surface of the head after the caulking.

3. The method according to claim 1, wherein the step of preparing the main frame includes:casting the main frame as the primary product not provided with the top opening; andforming the top opening by means of lasering.

4. The method according to claim 1, wherein the step of preparing the sole plate includes:providing a variable thickness for the sole plate which thickness gradually increases from the front to the rear of the head.

5. The method according to claim 1, wherein the step of preparing the sole plate includes:providing slits for the protrusion which slits are arranged at intervals along the length of the protrusion.

6. The method according to claim 1, wherein the step of preparing the main frame includes providing a front opening for the main frame, and the method further comprises the steps of:preparing a face plate made of a metal material of which specific gravity SGf is not more than the specific gravity SGm of the metal material of the main frame; andfixing the face plate to the main frame so that the face plate covers the front opening.

7. A hollow golf club head comprising a main frame provided with a front opening and a bottom opening and made of a material having a specific gravity SGm and a proof stress YSm,a face plate covering the front opening and made of a material having a specific gravity SGf, anda sole plate covering the sole portion and made of a material having a specific gravity SGs and a proof stress YSs,

8. The golf club head according claim 7, wherein the sole plate comprises a main part fitted in the bottom opening, and an anti-pullout part protruding from the bottom opening towards the inside of the head onto the inner surface of an edge part of the main frame around the bottom opening.

9. The golf club head according claim 7, wherein the sole plate and the main frame are soldered along their boundary on the outer surface of the head.

10. The golf club head according claim 8, wherein the thickness (tp) of the edge part of the main frame around the bottom opening is not less than the thickness (ts) of the main part of the sole plate.

11. The golf club head according claim 8, wherein the sole plate and the main frame are soldered along their boundary on the outer surface of the head.