US 4,928,972 · Granted 1990-05-29
How Yamaha Reinforced Golf Club Heads to Cut Down Vibration
Yamaha figured out how to build stronger, more stable golf club heads by layering fiber reinforcement and synthetic resin on the back side, plus adding adjustable weights to fine-tune where the club's center of gravity sits. The thicker the reinforcement, the longer and straighter the club — all designed to reduce the jarring shock when you hit the ball.
The plain-English version
What it protects
The claim covers a golf club iron head with fiber reinforcement (solid or hollow) bonded to the back surface, backed by synthetic resin. What's protected is the specific construction method: the progressively increasing thickness of reinforcement based on club length and loft angle, the use of a woven back plate to handle impact tension, the adjustable mass element embedded in the resin, and the optional rise member on the sole to shift the center of gravity. The bonding tape between layers is also part of what's locked down.
Why it matters
This patent represents Yamaha's entry into precision golf equipment manufacturing in the late 1980s, a sector dominated by established brands like Titleist and Callaway. By engineering vibration absorption and center-of-gravity adjustment into the club head itself, Yamaha could claim superior performance characteristics backed by patent protection. The innovation shows how non-traditional sports manufacturers could compete by applying materials-science rigor to equipment design.
Real-world use
When a golfer swings a Yamaha iron, the fiber-reinforced back absorbs and dampens the shock of impact, reducing hand vibration and allowing better control and accuracy on the shot.
Original USPTO abstract
A fiber reinforcement, which can be of solid or hollow construction, and a synthetic resin back up are disposed in a recess provided on the side of the club head remote from the shooting surface. A mass can be adjustably imbedded in the synthetic resin backup so as to increase the inertial moment of the club head. A rise member extending upwardly from the sole face of the club head can also be provided so that the center of gravity can be more easily adjusted. The fiber reinforcement is relatively thin for shorter shafted golf clubs having high degrees of loft, and increases progressively to a greater thickness for longer shafted golf clubs having relatively small degrees of loft. A back plate made of a woven cloth can be provided adjacent the fiber reinforcement to aid in reinforcing the shooting surface and to withstand the tension acting across the rear of the club head upon impact. The synthetic backup can be transparent or semi-transparent to expose the esthetics of the woven cloth. Bonding tape can be provided between the fiber reinforcement and the main body and between the fiber reinforcement and the back plate to facilitate the manufacture of the club head and to minimize the shock and vibration effect caused by striking a ball.
Patent details
- Publication number
- US 4,928,972
- Filing date
- 1989-05-23
- Grant date
- 1990-05-29
- Assignee
- Yamaha Corporation
- Inventor(s)
- NAKANISHI; TATSUO, TADOKORO; TOYOHIKO, FUJIMURA; MASAKI
- CPC class
- A63B53/04
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