[0001] The present invention relates to a golf club head and more particularly relates to
an improvement of the golf club head revealed in Swedish Patent Application 8101069-6.
Said head comprises a core body of a first plastics material and a housing tightly
surrounding the core body, said housing having a lateral opening which defines a free
striking surface on the core body, said core body having an exterior shape and dimensions
essentially corresponding to the exterior shape and dimensions of the finished club
head and said housing having the shape of a relatively thin-walled shell of at least
one other plastics material which has a higher modulus of elasticity than the first
plastics material and which surrounds the core body while exerting an initial stress
thereon, said core body having a cavity, the walls of which are at least partially
covered by a shell portion made in one piece with the shell, said shell portion defining
an interior chamber the bottom of which is covered by a sole plate.
[0002] One problem in the known club head is that cracks or ruptures can occur in the wall
of the core body which forms the striking surface of the head due to excessive deformation
of the wall when the golf ball is struck extremely hard. In order to eliminate this
problem, a further development according to the invention suggests that a bracing
wall be arranged which extends transversely to the striking surface from the rear
wall, as viewed in the direction of swing, of the chamber towards the forward wall
of the chamber and in that a heel-like projection is arranged on the forward wall
of the chamber directly in front of the end surface of the bracing wall, whereby the
facing end surfaces of the bracing wall and the heel define an upwardly narrowing
slot. Thus, when the striking wall is deformed by a powerful impact, the end surface
of the heel will come into contact against the end surface of the bracing wall. The
harder the impact is, the greater will be the effective area of contact between the
heel and the bracing wall. This provides a controlled deformation of the impact wall
at the same time as the shock wave generated when the wall is struck by the club head
will return to the striking surface via the bracing wall and the heel imparting an
extra acceleration force to the ball. Furthermore, the wedge-shaped slot between the
end surface of the bracing wall and the heel will result in an asymmetrical deformation
of the impact wall, so that it will yield more towards the bottom of the club head,
whereby the ball will be imparted a back-spin when leaving the club head, which is
desirable for the golfer to obtain an ideal ball path.
[0003] The invention will be described in more detail below with reference to the accompanying
drawing. Fig 1 is a view from below of the golf club head according to the invention
and Fig 2 is a cross-section along the line II-II in Fig 1.
[0004] The embodiment of the golf club head shown comprises a core body 1 which is made
of a suitable plastics material of high modulus of elasticity, e.g. a polyamide plastic,
such as "ZYTEL"
® . The core body 1 has essentially the same exterior shape as the intended finished
club head, but is proportionally somewhat smaller. The core body 1 is surrounded by
a housing, or shell 2 of a suitable plastics material which has a higher modulus of
elasticity than the material in the core body 1, e.g. a carbon fiber reinforced poly
amide plastic, such as nylon, which is, for example, extruded about the core body
1, so that the shell 2 surrounds and is in tight contact with the outside of the core
body 1 except along an essentially flat surface 3 which forms the striking surface
of the club head.
[0005] Furthermore, the core body 1 has an essentially centrally located cavity 4, which
opens towards the bottom of the club head. This cavity 4 is at least partially covered
by a shell portion 5 integral with the shell 2 and defining an inner chamber 6. The
cavity 4 and the shell portion 5 create a rectangular box-shape, as shown in Fig 1,
with the shell portion 5 side 7 adjacent to the striking surface 3 being possibly
completely or partially removed to reveal the core body 1. A sole plate 8 is mounted
on the bottom of the club head covering the chamber 6.
[0006] In accordance with the present invention, a bracing wall serving as an anvil extends
from the rear wall 10, as viewed in the direction of swing, of the chamber 6 towards
the forward wall 7 of the chamber. A heel 11 projects backwards from said forward
wall 7 and is directly opposite the end surface 12 of the bracing wall 9 (see Fig
1). The facing end surfaces of the bracing wall 9 and the heel 11 define between them
a slot which narrows upwardly. The heel 11 is designed to limit the movement backwards
of the impact wall 14 when the ball is struck by abutting against the striking surface
12 of the bracing wall. By virtue of the upwardly narrowing shape of the slot 13,
a non-symmetrical deformation of the impact wall 14 is obtained, so that the wall
is pressed in more towards the bottom of the club head, the result being that the
ball will be imparted a force component acting from below giving the ball a back spin
as it leaves the striking surface 13, thus improving its flight path.
Golf club head, comprising a core body (1) of a first plastics material and a housing
(2) tightly surrounding the core body (1) and having a lateral opening which defines
a free striking surface (3) on the core body (1), said core body (1) having an exterior
shape and dimensions essentially corresponding to the exterior shape and dimensions
of the finished club head and said housing (2) having the shape of a relatively thin-walled
shell of at least one other plastics material, which has a higher modulus of elasticity
than the first plastics material and which confines the core body (1) while exerting
an initial stress thereon, said core body (1) having a cavity (4), the walls of which
are at least partially covered by a shell portion (5) integral with the shell, said
shell portion (5) defining an interior chamber (6), the bottom of which is covered
by a sole plate (8), characterized in that a bracing wall (9) oriented transversely
to the striking surface (3) of the core body extends from the rear wall (10), as viewed
in the direction of swing, of the chamber (6) towards the forward wall of the chamber
and that a heel-like projection (11) is arranged on the forward wall of the chamber
directly in front of the end surface (12) of the bracing wall, whereby the facing
end surfaces of the bracing wall (9) and the heel (11) define an upwardly narrowing
slot (13).
