Appeal No. 2003-1610 Page 6
Application No. 09/715,128
ball at 160 ft/sec. Under moderate impact speed (lower than 160 ft/sec), which is
consistent with the nonprofessional golfer, trampoline plate 16 deflects freely and
produces a ball launch velocity higher then a conventional club head that
experiences little or no trampoline effect. When the impact speed is high in the
hands of a professional player, however, the trampoline plate's deflection is
arrested by the stopper plate. Consequently, the maximum launch velocity and
the coefficient of restitution remains within USGA regulation limits. The invention
thus allows the trampoline effect to increase the ball launch velocity for the
average golfer, but does not help the professional golfer, all within the USGA
regulations.
Referring now to FIGS. 1-3, trampoline plate 16 is shown in three different
positions. Just prior to striking ball 20, trampoline plate 16 is at a rest position
and is spaced from stopper plate 14 by a predetermined width or gap 18. At
moderate impact speed, the trampoline plate deflects freely, as shown in FIG. 2.
That is, upon striking the ball (not shown) trampoline plate 16 deforms and
deflects inwardly into gap 18. Due to resiliency, trampoline plate 16 rebounds to
give the ball a higher launch velocity. The stopper plate is inactive during
moderate impact speed, and behaves transparently to the spring-like action of
the trampoline plate. At the USGA specified high impact speed of 160 ft/sec,
however, the deflection of the trampoline plate is arrested by the stopper plate,
as shown in FIG. 3.
More specifically, the stopper plate is inactive at impact velocities below
120-140 ft/sec. At impact velocities of 120-140 ft/sec the gap width is such that
upon deflection the trampoline plate just touches the stopper plate. At impact
velocities greater than 120-140 ft/sec, particularly at 160 ft/sec, the stopper plate
arrests any further deflection of the trampoline plate.
The trampoline effect is dependent on the characteristics of the
trampoline plate. Depending on the materials used, the effect is usually more
pronounced if the plate is thin. Compared to a thick trampoline plate, a thin plate
deflects more during ball impact, and rebounds more to give the ball a higher
launch velocity. The energy loss during impact is mostly in the ball, due to the
viscosity and large deformation of the ball. In order to reduce energy loss,
deformation of the ball may be reduced. This is achievable by increasing the
deformation of the trampoline plate which, in turn, results in reducing the
deformation of the ball. Higher deformation, or deflection, in the trampoline plate
may be achieved by using a thin plate with materials having low stiffness
(Young's modulus) and high strength. Materials that have these properties
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Last modified: November 3, 2007