Golf club head
A hollow golf club head which is composed of a metal part made of at least one kind of metal material and a FRP part made of a fiber reinforced resin, the metal part having a first lap joint part, and the FRP part having a second lap joint part being lap-jointed with the first lap joint part, wherein one of the first lap joint part and second lap joint part is provided with at least one securing hole, and the other is provided with at least one protrusion engaging with said at least one securing hole.
1. A hollow golf club head composed of a metal part made of at least one kind of metal material and a FRP part made of a fiber reinforced resin,
the metal part having a first lap joint part, and the FRP part having a second lap joint part lap-jointed with the first lap joint part, wherein
one of the first lap joint part and second lap joint part is provided with at least one securing hole, and the other is provided with at least one protrusion engaging with said at least one securing hole, wherein said at least one securing hole is a plurality of holes having a total area S 1 in a range of not less than 20% of the overall area S of the lap joint.
2. The golf club head according to claim 1 , wherein the metal part includes a face wall which forms the club face for hitting a ball.
3. The golf club head according to claim 1 , wherein
the first lap joint part of the metal part is provided with said at least one securing hole, and
the second lap joint part is provided with said at least one protrusion.
4. The golf club head according to claim 1 , wherein
the metal part has an opening on the top thereof, and
the FRP part covers the opening and forms at least a part of a crown portion of the head.
5. The golf club head according to claim 4 , wherein
the first lap joint part is formed continuously along the entire circumference of the opening, and
the second lap joint part is formed continuously along the entire circumference of the FRP part.
6. The golf club head according to claim 4 , wherein the FRP part comprises
a crown wall forming a crown portion, and
a flange extending downwards from an edge of the crown wall to form the surface of an upper part of the side portion of the head.
7. The golf club head according to claim 6 , wherein the second lap joint part includes a part bridging between the crown wall and flange.
8. The golf club head according to claim 6 , wherein both the crown wall and flange in the bridging part are provided with the protruson and/or securing hole.
9. The golf club head according to claim 1 , wherein
the head volume is in a range of from 370 to 550 cc,
the height of the center of gravity of the head in a range of from 25 to 35 mm, and
the depth of the center of gravity of the head in a range of from 35 to 43 mm.
10. The golf club head according to claim 1 , wherein the total area S 1 is not less than 30% of the overall area S.
11. The golf club head according to claim 1 , wherein the total area S 1 is not more than 70% of the overall area S.
12. The golf club head according to claim 1 , wherein the total area S 1 is not more than 60% of the overall area S.
13. The golf club head according to claim 1 , wherein the securing hole and protrusion have a diameter of not less than 3 mm.
14. The golf club head according to claim 13 , wherein the diameter is not more than 8 mm.
15. The golf club head according to claim 13 , wherein the diameter is not more than 5 mm.
16. The golf club head according to claim 1 , wherein said at least one protrusion is formed integrally with the FRP part from the fiber reinforced resin thereof.
17. The golf club head according to claim 1 , wherein each said protrusion is provided at the end thereof with a retainer larger than the securing hole.
18. A hollow golf club head composed of a metal part made of at least one kind of metal material and a FRP part made of a fiber reinforced resin,
the metal part having a first lap joint part, and the FRP part having a second lap joint part lap-jointed with the first lap joint part, wherein
one of the first lap joint part and second lap joint part is provided with at least one securing hole, and the other is provided with at least one protrusion engaging with said at least one securing hole, and
the second lap joint part of the FRP part includes: an inside part abutting on the inside of the first lap joint part; and an outside part abutting on the outside of the first lap joint part to have a two-forked cross sectional shape.
19. A hollow golf club head composed of a metal part made of at least one kind of metal material and a FRP part made of a fiber reinforced resin,
the metal part having a first lap joint part, and the FRP part having a second lap joint part lap-jointed with the first lap joint part, wherein
one of the first lap joint part and second lap joint part is provided with at least one securing hole, and the other is provided with at least one protrusion engaging with said at least one securing hole, wherein said at least one protrusion is formed integrally with the FRP part from said fiber reinforced resin, and
each said securing hole is a through hole.
20. A hollow golf club head composed of a metal part made of at least one kind of metal material and a FRP part made of a fiber reinforced resin,
the metal part having a first lap joint part, and the FRP part having a second lap joint part lap-jointed with the first lap joint part, wherein
one of the first lap joint part and second lap joint part is provided with at least one securing hole, and the other is provided with at least one protrusion engaging with said at least one securing hole, wherein said at least one protrusion is formed integrally with the FRP part from said fiber reinforced resin, and
the first lap joint part and second lap joint part are formed in both of a crown portion and a side portion of the head.