Note: Descriptions are shown in the official language in which they were submitted.
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Backqround
This invention relates to a wood type of golf
clubhead. More particularly the invention relates to a golf
clubhead which has a recessed or inverted hosel portion, a hosel
tube which is inserted into an opening in the hosel portion, an
alignment groove for aligning the clubhead, a flat sole portion,
and an aerodynamic shape.
Golf clubs of the wood type are no longer made only
from wood. Such clubs are now commonly made from metal such as
stainless steel, titanium, and aluminum and from composite
material such as fibers of graphite, Kevlar, or boron and resin.
Many golf clubheads include a hosel which extends
upwardly above the face of the clubhead for attaching the shaft
of the clubhead. However, a conventional hosel increases weight
in the high heel area. It is becoming increasingly common for
golf club designers to redistribute the weight of the clubhead
-to the high toe and low heel areas as taught, for example, by
U.S. Patent Nos. 4,471,961 and 5,120,062.
Some clubheads have used a shorter hosel to reduce
weight in the high heel area. For example, U.S. Patent Nos.
5,042,806 and 5,240,252 describe clubheads in which the hosel
does not extend above the face. However, such a clubhead does
not provide the same support for the shaft as does a clubhead
with a traditional hosel.
Another problem with wood type clubheads is properly
aligning the face of the clubhead. With iron type clubheads
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many golfers use the bottom groove of the face to align the
clubhead square, i.e., perpendicular, to the intended line of
flight. The top line of an iron clubhead cannot be used to
align the clubhead because the top line is not perpendicular to
the intended line of flight as viewed by a golfer at address.
However, the face of a wood type golf club has a low
loft angle, and the grooves of the face are not easily apparent
and usable for alignment at address. Using the face grooves for
alignment is also complicated by the fact that the face of most
wood type clubheads is provided with bulge and roll curvature,
as explained, for example, in U.S. Patent No. 4,471,961.
Many wood type golf clubs therefore include some
alignment indicator such as a line or arrow on the top of the
clubhead which indicates the intended line of flight. However,
some golfers prefer to use the face for aligning the clubhead
square rather than relying on an indicator on top of the
clubhead.
Summary of the Invention
In accordance with the invention, a clubhead is
provided with an inverted or recessed hosel portion. The
inverted hosel portion includes a generally concave wall which
curves toward the sole of the clubhead and reduces the weight in
the high heel area. The shaft is reinforced by a hosel tube
which extends upwardly from the inverted hosel portion. The
hosel tube is formed from light yet strong material, such as
titanium, to minimize the weight in the hosel portion. A
portion of the hosel tube coacts with the hosel portion to
~restrain relative rotation~b2e~ween ~he hosel tube and the hosel
portion.
The clubhead is also provided with an alignment groove
at the intersection of the face and the crown of the clubhead.
A portion of the alignment groove lies in a vertical plane which
is perpendicular to the midplane of the clubhead and allows a
golfer to align the clubhead square to the line of flight.
The sole includes a flat portion which supports the
clubhead in the address position. The toe portion and rear
portion of the club extend upwardly from the flat portion to
merge with the crown in a generally V-shaped aerodynamic
profile.
Description of the Drawing
The invention will be explained in conjunction with an
illustrative embodiment shown in the accompanying drawing, in
which --
Figure 1 is a fragmentary perspective view of a golfclub formed in accordance with the invention;
Figure 2 is a front elevational view of the clubhead;
Figure 3 is a top view of the clubhead;
Figure 4 is a toe end view of the clubhead taken along
the line 4-4 of Figure 2;
Figure 5 is a heel end view of the clubhead taken
along the line 5-5 of Figure 2;
Figure 6 is a sectional view taken along the line 6-6
of Figure 3;
Figure 7 is an enlarged fragmentary view of a portion
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of Figure 7;
Figure 8 is a bottom view of the clubhead;
Figure 9 is a fragmentary sectional view taking the
line 9-9 of Figure 3;
Figure 10 is a fragmentary sectional view taken along
the line 10-10 of Figure 9;
Figure 11 is a fragmentary sectional view taken along
the line 11-11 of Figure 3;
Figure 12 is a view similar to Figure 1 of another
embodiment of a clubhead;
Figure 13 is a front elevational view of the clubhead
of Figure 12;
Figure 14 is a bottom view of the clubhead of Figure
12;
Figure 15 is an enlarged side view of the hosel tube
of Figure 12;
Figure 16 is a sectional view taken along the lines
16-16 of Figure 15;
Figure 17 is an end view taken along the lines 17-17
of Figure 16;
Figure 18 is a fragmentary sectional view of the hosel
portion of the clubhead of Figure 12 without the hosel tube;
Figure 19 is a fragmentary sectional view of the hosel
portion taken along the line 19-19 of Figure 18;
Figure 20 is a fragmentary sectional view taken along
the line 20-20 of Figure 18;
Figure 21 is a sectional view of another embodiment of
a hosel tube;
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Figure 22 is a view similar to Figure 21 with a screw
inserted in the hosel tube;
Figure 23 is a perspective view of yet another
embodiment of a hosel tube;
Figure 24 is a fragmentary sectional view taken along
the line 24-24 of Figure 23; and
Figure 25 is a fragmentary sectional view similar to
Figure 18 of a hosel portion of a clubhead which has been
modified to accept the hosel tube of Figure 23.
Description of Specific Embodiments
Figure 1 illustrates a wood type of golf club 15 which
includes a clubhead 16 and a shaft 17. The particular clubhead
illustrated is formed from metal, but the clubhead can also be
formed from other material such as wood and composites.
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The clubhead includes a face 19, a generally convex
top portion or crown 20, and a generally convex bottom portion
21. The top and bottom portions merge to form a curved
peripheral edge 22 which is relatively sharp or streamlined
(Figures 2, 4, 5, and 6).
The bottom portion of the clubhead includes a sole 24,
a toe wall 25 (Figure 2) which merges with the edge 22, a rear
wall 26 (Figures 4 and 5) which merges with the edge 22, and a
heel wall 27 (Figure 2) which merges with the edge 22. Both the
toe wall 25 and the rear wall 26 form a relatively sharp
included angle with the crown 20 at the edge 22, i.e., an angle
which is no greater than about 90.
The sole 24 includes a flat portion or pad 29 (Figures
2, 6, and 8). The flat portion is designed to support the
clubhead on the ground at address in the proper loft and lie
orientation. Although individual golfers might hold a
particular clubhead differently at address, clubheads are
designed with specific loft and lie angles which are measured
with respect to one orientation of the club. See, for example,
the discussion in U.S. Patent No. 5,150,550.
Referring to Figure 2, the angle A between the
centerline CL of the shaft and a horizontal ground plane G
determines the lie of the clubhead. Referring to Figure 4, the
angle B between the face 19 and a vertical plane V determines
the loft of the clubhead. If the face includes bulge and/or
roll curvature and is not planar, the loft angle is determined
by a plane which is tangent to the center of the face. The
tangent plane extends perpendicularly to a vertical midplane MP
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which extends through the center of the face perpendicular to
the ground plane G and the vertical plane V. The flat portion
19 of the sole is coplanar with the ground plane G at address,
and the size of the flat portion is preferably sufficient to
provide tactile feedback to the golfer to enable the golfer to
be aware of the correct address position.
A groove 30 (Figure 8) is provided in the sole pad 29
to facilitate moving the flat portion through turf, soil, or
sand as the clubhead impacts the ball, the groove is aligned
with the midplane MP and terminates in a flared rear end 31.
The rear wall 26 is slightly convex in Figures 4-6 and
curves upwardly and rearwardly from the sole pad 29 to the edge
22. The toe wall 25 and heel wall 27 are also generally convex
and curve outwardly and upwardly to the edge 22. The toe
portion 32 of the face (Figure 2) is relative sharp and V-
shaped, and the included angle of the V is about 90.
A hosel portion 33 is located at the juncture between
the crown 20 and the heel portion 34 of the face. The hosel
portion includes an inverted or recessed portion 35 which is
provided by a generally arcuate or concave wall 36. Referring
to Figures 2 and 9, the concave wall 36 curves inwardly from the
edge 22 toward the toe and upwardly toward the crown. The
concave wall is generally channel-shaped and extends along an
axis 37 (Figures 3 and 5) which is preferably substantially
perpendicular to the vertical plane V at address.
In one specific embodiment of the invention, the
concave wall was circular and had a radius of about 1/2 inch.
The wall extended over an arc of about 90. The maximum depth
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of the recess measured from a line extending across the recess
from the shoulder 38 at the crown to the shoulder 39 at the heel
was about 0.15 inch.
A hosel tube 41 extends upwardly from the center of
the inverted portion 37 beyond the top of the crown 20. The
shaft 17 is secured within the hosel tube by epoxy or adhesive.
The hosel tube is preferably formed from titanium which is
strong yet lightweight. The titanium tube reinforces the shaft
without contributing excessive weight to the high heel area.
However, the hosel tube can also be made of the same material as
the clubhead, such as stainless steel and can also be formed
integrally with the clubhead during the casting process.
The inverted portion 35 of the hosel reduces the
amount of material and the weight in the hosel area. The
reduction in weight in the hosel area enables weight to be
redistributed to other areas of the clubhead, for example the
high toe and low heel areas. The inverted portion also lowers
the center of gravity of the clubhead and reduces drag or air
resistance as the clubhead is swung. The combination of the
inverted portion and the streamlined or tear drop shaped profile
provided by the sharp peripheral edge 22 improves the
aerodynamic features of the clubhead.
The inverted hosel portion also positions the shaft
centerline farther from the heel and closer to the center of
gravity CG (Figure 2) of the clubhead. Since the hosel tube 41
and the shaft extend through the center of the concave wall 36,
the shaft is spaced away from the shoulder 39 on the heel.
The particular clubhead illustrated in Figures 1-11 is
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formed from 17-4 stainless steel by investment casting. As is
well known in clubhead manufacturing, the investment casting
process forms a hollow clubhead with an open bottom. The
opening in the bottom is closed by a soleplate which is welded
to the periphery of the opening.
Referring to Figures 9-11, a generally cylindrical
boss or lug 44 is formed integrally with the rear surface 45 of
the face. A portion of the boss advantageously extends to the
heel wall 27 along the inside surface of the face to form an
internal casting gate 46 for the molten metal which forms the
clubhead.
As described in U.S. Patent No. 5,346,218, a mold for
casting a metal clubhead conventionally includes an external
gate through which the molten metal is poured. However, molds
for large clubheads advantageously also include internal gates
to facilitate flow of molten metal throughout the mold cavity.
The boss 44 is formed by an internal gate in the mold which
communicates with the conventional external gate at the heel
portion of the mold. The internal gate facilitates the casting
of the boss, the face, and the crown and also provides weight in
the low heel area of the clubhead.
The boss is cast with an internal cylindrical bore 47
(Figure 9) for the hosel tube 41. The hosel is permanently
secured within the bore by epoxy. The hosel can also be
additionally or alternately secured by screw threads, mechanical
force fit, interlock mechanism, etc. The bore terminates in a
bottom wall 48 which supports the bottom of the hosel tube and
the shaft. The bottom wall is provided with an opening 49 to
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permit the clubhead to be filled with polyurethane foam if desired.
The clubhead can also be cast from titanium or other
suitable metal. Titanium is lighter than stainless steel and a
titanium clubhead can be larger than a steel clubhead of the
same weight. Since molten titanium flows more easily than
molten steel, a titanium clubhead does not need an internal gate
for the boss 44. The boss of a titanium clubhead can be formed
integrally with the rear surface of the face 52 of the clubhead
but does not need to extend to the heel wall.
Referring to Figures 1 and 2, the front surface of the
face 19 of the clubhead 16 is provided with conventional grooves
55 which are substantially parallel to the ground plane G. The
specific embodiment of the clubhead which is illustrated in the
drawing included bulge and roll curvatures which were oriented
about axes 45 from the ground plane as described in U.S. Patent
No. 4,471,961.
An alignment groove, cut, or recess 56 is provided at
the intersection between the face 19 and the crown 20. The
alignment groove curves upwardly between the toe portion and the
heel portion of the edge 22 and forms the top edge of the face
and the front edge of the crown. Referring to Figures 3, 4, and
7, the alignment groove includes a rear surface 57 which lies in
a plane which is parallel to or substantially parallel to the
vertical plane V.
The alignment groove is readily visible to the golfer
at address and enables the golfer to align the clubhead by
squaring the alignment groove to the intended line of flight.
Even though the alignment groove follows the curvature of the
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crown 20, it appears straight or substantially straight to the
golfer when viewed at address, particularly because the rear
surface of the groove lies in a substantially vertical plane and
is therefore substantially straight.
If desired, the plane of the alignment groove can be
angled with respect to the face to provide an open or closed
face when the alignment groove is squared in order to compensate
for a hook or a slice.
In the preferred embodiment the alignment groove is
located at the intersection of the face and crown. However, the
alignment groove could also be located on the crown behind the
face or on the face below the crown. The alignment groove is
preferably formed during the casting process.
Alternatively, alignment means could be provided by a
painted or cut line or other indicia which extended
substantially parallel to the vertical plane V.
Referring to Figures 12-14, another embodiment of a
clubhead 61 is similar to the clubhead 16. However, the sole 62
of the clubhead 61 is not provided with a groove. Instead, the
sole has a flat portion or pad 63 with a flat surface which
supports the clubhead on the ground at address.
The hosel portion 64 of the clubhead includes a
cylindrical boss 65 (Figure 18) which has a cylindrical bore 66
and a bottom wall 67 (Figures 19 and 20). The outside surface
of the boss can be connected to the face or heel wall of the
clubhead, or the boss can be formed independently of the face
and heel wall. The bottom wall is provided with a slot 68 which
extends diametrically across the bottom of the bore.
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A hosel tube 70 (Figures 15-17) includes a cylindrical
portion 71 and a pair of lugs 72 which extend from the bottom
end of the tube. Each lug is formed as an extension of the
cylindrical side wall of the tube and has an arcuate curvature
(see Figure 17). The hosel tube also includes a knurled portion
73 which is intended to be positioned in the bore 66 of the
hosel portion of the clubhead.
The outside diameter of the hosel tube is slightly
larger than the bore 66, and the lugs 72 are sized to fit
relatively snugly into the slot 68 to substantially prevent
rotation of the hosel tube within the bore. The bottom edge 74
of the hosel tube between the lugs is supported by the bottom
wall 67 of the bore. The hosel tube can be secured within the
bore by epoxy or adhesive.
The lugs prevent relative twisting between the hosel
tube and the clubhead which could cause the adhesive bond to
fracture. The knurled portion 73 further strengthens the
attachment between the hosel tube and the clubhead.
If desired, the hosel tube can bear printing or other
indicia 75 which is positioned relative to the lugs 72 so that
the lugs are aligned with the slot 68 when the indicia is
properly oriented with respect to the clubhead. For example,
the indicia can be positioned on the hosel tube so that when the
indicia is facing the clubface, the lugs are aligned with the
slot. Proper insertion of the hosel tube is thereby
facilitated. The side edges 76 of the lugs are also slightly
tapered to facilitate insertion of the lugs into the slot.
Additional embodiments of the hosel tube are
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illustrated in Figures 21-24. In Figure 21 a hosel tube 78
includes a cylindrical side wall 79 and a bottom wall 80 which
is provided with a central opening 81. A stainless steel
thread-cutting Torx head screw 82 is inserted through the
opening 81.
The hosel tube 78 is intended to be used with a
clubhead of the type illustrated in Figures 9-11 which has an
opening 49 in the bottom of the boss which provides the hosel
tube bore. The opening is smaller than the screw 82, and the
hosel tube is attached to the clubhead by threading the screw
into the opening.
Referring to Figures 23 and 24, a hosel tube 84 has a
cylindrical side wall 85 and a bottom wall 86. A projection 87
is formed on the bottom wall, and the projection has a non-
circular periphery. In the embodiment illustrated in Figures 23
and 24, the projection has a rectangular periphery or side wall
88. The bottom wall may optionally be provided with a central
opening 89.
Figure 25 illustrates a clubhead boss so for the hosel
tube 84. The boss includes a cylindrical side wall 91 and a
bottom wall 92. A depression or socket 93 is formed in the top
surface of the bottom wall and has a shape corresponding to the
shape of the projection 87. The bottom wall may also be
provided with an opening 94.
The hosel tube 84 is inserted into the boss 90 so that
the projection 87 is positioned in the socket 93 to prevent
relative rotation between the hosel tube and the clubhead. The
hosel tube can be secured by adhesive or epoxy. Additional
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securement can be provided, if desired, by inserting a screw
through the openings 89 and 94.
While in the foregoing specification a detailed
description of specific embodiments of the invention was set
forth for the purpose of illustration, it will be understood
that many of the details herein given can be varied considerably
by those skilled in the art without departing from the spirit
and scope of the invention.
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