EP0556502B1

EP0556502B1 - Wood type golf clubs

Info

Publication number: EP0556502B1
Application number: EP92307112A
Authority: EP
Inventors: John A. Solheim; Anthony D. Serrano
Original assignee: Karsten Manufacturing Corp
Current assignee: Karsten Manufacturing Corp
Priority date: 1992-02-21
Filing date: 1992-08-04
Publication date: 1996-09-18
Anticipated expiration: 2012-08-04
Also published as: CA2072706C; DE69213919T2; AU2072792A; EP0556502A1; CA2072706A1; JPH06105937A; ZA924839B; ES2093203T3; KR0167569B1; JPH0815500B2; DE69213919D1; KR930017590A; AU655647B2

Description

This invention relates generally to golf clubs and, in particular, to a type of golf club commonly referred to as "woods" which have an enlarged head attached to one end of an elongated shaft.
A full set of golf cIubs generally consists of a correlated set of wood type clubs and a correlated set of iron type clubs. A conventional wood type golf club is disclosed in U. S. Patent No. 3,625,518 while conventional iron type golf clubs are disclosed in U. S. Patent No. 3,655,188. Wood type golf clubs have heads constructed of materials such as wood, metal and plastic. Iron type golf clubs have heads usually made of metal.
Referring to Figs. 1 - 3, a wood type golf club according to the prior art has an enlarged head 10 including a specially shaped body 12 preferably formed of wood with a hosel 14 which receives and is attached to one end of an elongated shaft 16. A grip (not shown) is mounted on the other end of the shaft 16 so that head 10 may be swung in an arc to contact a golf ball resting on a tee or on the ground. An insert 18 preferably formed of a resin material is centrally mounted in a face portion 12a of the body 12, and a metallic sole plate 20 is attached to a bottom portion 12b of the body 12 by a plurality of screws 22 and/or epoxy. The sole plate 20 has an arcuate notch 24 at one end and a straight edge 26 at the other end. When the sole plate is attached to the body 12, the notch 24 and the edge 26 are engaged with an arcuate shoulder 28 and a straight shoulder 30, respectively, formed on the body 12. The sole plate 20 also has a curved side 32 and a relatively straight side 34. Shoulder 30 is located in a heel 10a of the head 10 while shoulder 28 is located in a toe 1Ob of the head 10.
When making a wood type golf club that is designated as a driver or a No. 1 wood, a hole 36 shown in Fig. 1 is bored in the bottom of the driver body 12 to remove weight therefrom so that the finished golf club will have a desired swingweight. Swingweight is generally defined as a measurement of a golf club's weight distribution about a point which is at a specified distance from the grip end of the golf club. Hole 36 is necessary because the body 12 in a driver is larger and heavier than in other golf clubs in a correlated set. When making other wood type golf clubs with relatively smaller heads (e.g., those designated as Nos. 3, 5 and 7 woods), holes 38, 40 shown in Fig. 2 are bored in the body 12 and then filled with weighted inserts 39, 41 made of lead or brass in order to provide finished golf clubs of desired swingweights. In a correlated set of wood type golf clubs according to the prior art including for example Nos. 1, 3, 5 and 7 woods, the sole plates 20 on the Nos. 3, 5 and 7 have been made of a heavyweight material such as brass whereas the sole plate 20 on the No. 1 wood has been made of a lightweight material such as aluminum. This helps to reduce, but not eliminate, the additional weight that must be added to the body 12 in the Nos. 3, 5 and 7 woods by using the weighted inserts 39, 41.
The golf club shown in Figs. 1 - 3 has the face portion 12a of the body 12 arranged for contacting a golf ball. Located on the face portion 12a is a center point 11 known as a "sweet spot" which is in general alignment with the center of gravity of the head 10. If the head 10 impacts a golf ball at precisely the sweet spot 11 during a golf swing, maximum energy will be transferred from the head 10 and the golf ball will travel along its intended path. If the club head 10 impacts a golf ball at off-center points 11a, 11b which are also located on the face portion 12a but in the heel and toe 1Oa, 1Ob of the head 10, twisting movements of the head 10 will occur resulting in less than maximum energy being transferred from the head 10 and deviation of the golf ball from its intended path of travel. Such deviation of the golf ball is generally referred to as a "slice" or a "fade" when impacting the head 10 at point 11a and as a "hook" or a "draw" when impacting the head 10 at point 11b.
Another known construction of wood type golf club head, similar to that described above, is disclosed in US 4 795 159. Here a metallic sole plate is inserted into and fixed to a local recess formed in the sole face of a fiber reinforced plate shell of the head, for the purposes of protecting the shell and weight adjustment. For the latter, a mass in the form of a threaded bolt is inserted into the base of the head, through a centrally located region of the sole plate.
In one aspect of the present invention, a wood type golf club comprises a shaft and a head attached to one end of the shaft. The head includes a body with a face portion arranged for contacting a golf ball. A sole plate is attached to a bottom portion of the body. The sole plate has a majority of its weight concentrated around its perimeter preferably by providing a cavity in an interior surface of the sole plate. A first proportion of the sole plate weight is preferably concentrated in a heel of the head, and a second proportion of the sole plate weight is preferably concentrated in a toe of the head. These first and second weight proportions together preferably constitute more that 50 percent of the sole plate weight that is concentrated in the perimeter of the sole plate.
In another aspect of the present invention, a wood type golf club as defined above has a desired swingweight in a desired range, the head having a total head weight which is used in calculating the swingweight, and the body of the golf club having a weight which is less than the total head weight. The sole plate is selected from a plurality of sole plates formed of identical material and each having a majority of its weight concentrated around a perimeter thereof, the plurality of sole plates having different weights such that the selected sole plate has a weight which is less than the total head weight of the head. The total head weight is equal to the weight of the body plus the weight of the selected sole plate.
A further aspect of the present invention provides a method of making a wood type golf club having a desired swingweight. The golf club includes a head attached to one end of a shaft. The head has a total head weight which is used in calculating the swingweight. The method comprises the steps of providing a body in the head with a face portion for impacting a golf ball, weighing the body to insure that it has a weight which is within a preselected range that is less than the total head weight, selecting a sole plate from a plurality of sole plates formed of identical material and each having a majority of its weight concentrated around a perimeter thereof, the plurality of sole plates having different weights such that the selected sole plate has a weight which is equal to the total head weight minus the weight of the body, and attaching the selected sole plate to a bottom portion of the body.
Another aspect of the present invention provides a correlated set of wood type golf clubs including at least two golf clubs of different number designations wherein one of the number designations is higher than the other number designation. Each golf club is a wood type golf club according to the main aspect of the invention, as defined above. The head of each golf club has a respective total head weight and the sole plate of each respective golf club has a respective weight which is less than the respective total head weight. According to this aspect of the invention, an improvement comprises the weight of the sole plate on the golf club with the higher number designation being greater than the weight of the sole plate on the golf club with the other number designation. Both of the sole plates are formed of identical material. A preferred embodiment of the invention will now be described in detail, with reference to the accompanying drawings, in which:

Fig. 1 is an exploded perspective view of a golf club head according to the prior art;
Fig. 2 is an exploded perspective view of another golf club head according to the prior art;
Fig. 3 is a bottom perspective view of the prior art golf club heads shown in Figs. 1 and 2 taken when they are assembled;
Fig. 4 is an exploded perspective view of a golf club head according to the preferred embodiment of the present invention;
Fig. 5 is a bottom perspective view of the golf club head shown in Fig. 4 taken when it is fully assembled;
Fig. 6 is a vertical cross-sectional view of the golf club head shown in Fig. 5; and
Fig. 7 is a top plan view of a sole plate used in the golf club head of Figs. 4 - 6.

Referring to Fig. 4, a wood type golf club according to the preferred embodiment of the present invention includes an enlarged head 42 having a specially shaped body 44 and a sole plate 46 which is attached to a bottom portion 44a of the body 44 by conventional means such as a plurality of screws 48 and/or epoxy. The body bottom portion 44a has a bottom surface of compound curvature. An insert 50 preferably formed of a resin material is mounted in a face portion 44b of the body 44. The face portion 44b is arranged for impacting a golf ball. The body 44 includes a neck or hosel 52 with a bore 54 (Fig. 6) therethrough for receiving and attachment to one end of an elongated shaft 56. Mounted on the other end of the shaft 56 is a grip (not shown). In the preferred embodiment of the head 42, body 44 is formed of wood and sole plate 46 is made of metal. Alternatively, body 44 could be made of other suitable materials such as plastic or metal.
If the head 42 is manufactured for use on a wood type golf club designated as a driver (i.e. No. 1 wood) with the body 44 made of wood, a hole 58 is bored in the bottom of the body 44 to remove weight therefrom so that when the sole plate 46 is attached, the head 42 will have a desired total head weight which is used in calculating a swingweight for the golf club. As previously stated swingweight is generally defined as a measurement of a golf club's weight distribution about a point which is at a specified distance from the grip end of the golf club. If the head 42 is manufactured for use on a wood type golf club such as those designated as a No. 3, 5 or 7 wood with the body 44 made of wood, no weight is removed from the body 44 before attachment of the sole plate 46. Therefore, in all woods except the driver such as the Nos. 3, 5 and 7 woods, the boring of hole 58 is not required.
The swingweight for the golf club shown in Figs. 4 - 7 is determined by taking into account the total head weight of the head 42 and other factors such as the weight and length of the shaft 56. The body 44 and the sole plate 46 each have an individual weight which is less than the total head weight of the head 42. When making the head 42, the body 44 is weighed to insure that its weight is within a preselected range, and then the sole plate 46 is selected from a plurality of sole plates which are formed of identical material (e.g., aluminum) but have different weights so that the weight of the selected sole plate 46 is equal to the total head weight less the weight of the body 44. Instead of using additional weights (e.g., weighted inserts 39, 41) in the body 44 to compensate for deficiencies in the total head weight of the head 42 as in prior art golf clubs, the weight of the sole plate 46 is increased by merely selecting a heavier sole plate.
As seen in Figs. 4, 6, and 7, the sole plate 46 has a substantially circular cavity 60 formed in its interior surface and located generally intermediate a heel 42a and a toe 42b of the club head 42. The cavity 60 has inclined side walls and a relatively flat bottom wall. The inclined side walls of the cavity 60 form an acute angle with the bottom surface of the body 44 which is adjacent the hole 58 as best shown in Fig. 6. Alternatively, the cavity 60 could be of a different shape such as an oval. The purpose of cavity 60 is to concentrate a majority of the weight of the sole plate 46 in perimeter sections 46a, 46b, 46c and 46d (Fig. 7) of the sole plate 46 by reducing the weight of the sole plate 46 in its center section 46e. Thus, the cavity 60 in the sole plate 46 results in perimeter weighting of the club head 42. An advantage of this perimeter weighting is improved weight distribution in the heel and toe 42a, 42b of the club head 42 which causes the club head 42 to resist twisting movements in directions indicated by arrow 62 in Fig. 5 when impacting a golf ball at off- center points 43a, 43b located on the body face portion 44b in the heel and toe 42a, 42b of the head 42. No such twisting movements of the club head 42 occur when impacting a golf ball at a center point or "sweet spot" 43 which is also located on the body face portion 44b.
The sole plate 46 has an extended heel section 46a and an extended toe section 46b. The extended heel section 46a concentrates a first proportion of the perimeter weight of the sole plate 46 in the heel 42a of the club head 42 while the extended toe section 46b concentrates a second proportion of the sole plat perimeter weight in the club head toe 42b. When combined, these first and second perimeter weight proportions constitute more than 50 percent of the perimeter weight of the sole plate 46.
It should be noted that the sole plate 46 does not have a notch such as notch 24 in sole plate 20 or a straight edge such as straight edge 26 on sole plate 20. Therefore, the sole plate 46 is significantly heavier at its ends than the sole plate 20 thereby resulting in the club head 42 having increased heel and toe weighting when compared with the club head 10. Due to the cavity 60, sole plate 46 has significantly less weight at its center than the sole plate 20. This also contributes to the improved heel and toe weighting of the club head 42.
It will be understood that when the club head 42 is constructed for use on a golf club designated as a No. 1 wood, the sole plate 46 will weigh less than when the club head 42 is constructed for use on a golf club designated as a No. 3, 5 or 7 wood. This is because in a No. 1 wood, the body 44 weighs more than in the other woods. In all of the woods, the combined weights of the body 44 and the sole plate 46 must be within a preselected range in order to provide a desired swingweight.
In a correlated set of golf clubs, the diameter and the depth of the cavity 60 may be changed in order to increase or decrease the weight of the sole plate 46. For example in a No. 5 wood, the cavity 60 has a smaller diameter and is shallower than in a No. 3 wood which results in the sole plate weight being greater in the No. 5 wood.

Claims

A wood type golf club comprising:
a shaft (56);

a head (42) attached to one end of said shaft, said head including a body (44) having a face portion (44b) arranged for impacting a golf ball; and

a sole plate (46) attached to a bottom portion (44a) of said body (44), said sole plate having a weight; characterized in that a majority of the sole plate weight is concentrated around a perimeter (46a, 46b, 46c, 46d) of said sole plate (46).
A wood type golf club according to claim 1, wherein:
said head (42) has a heel (42a) and a toe (42b); and

said sole plate (46) has a heel section (46a) disposed in said heel (42a) and a toe section (46b) disposed in said toe (42b).
A wood type golf club according to claim 2, wherein:
said heel section (46a) of said sole plate (46) concentrates a first proportion of the sole plate weight in said heel (42a) of said head (42);

said toe section (46b) of said sole plate (46) concentrates a second proportion of the sole plate weight in said toe (42b) of said head (42); and

said first and second proportions together constitute more than 50 percent of said majority of the sole plate weight.
A wood type golf club according to any preceding claim, further comprising a cavity (60) in said sole plate (46) which is effective to concentrate said majority of the sole plate weight around the perimeter (46a, 46b, 46c, 46d) of the sole plate (46).
A wood type golf club according to claim 4, wherein:
said sole plate (46) has an interior surface and an exterior surface; and

said cavity (60) is formed in the interior surface of said sole plate (46).
A wood type golf club according to claim 4 or claim 5, wherein said cavity (60) is substantially circular.
A wood type golf club according to any of claims 4 to 6, when dependent on claim 2, wherein said cavity (60) is located, generally intermediate said heel (42a) and said toe (42b) of said head (42).
A wood type golf club according to any of claims 4 to 7, wherein said cavity (60) has inclined side walls which form an acute angle with a bottom surface of said body (44).
A wood type golf club according to any preceding claim, wherein said body (44) is formed of wood, and wherein said sole plate (46) is made of metal.
A wood type golf club according to any preceding claim and having a desired swingweight, said head (42) having a total head weight which is used in calculating said swingweight, and
said body (44) having a weight which is less than said total head weight; wherein:

said sole plate (46) is selected from a plurality of sole plates formed of identical material and each having a majority of its weight concentrated around a perimeter thereof, the said plurality of sole plates having different weights such that the selected sole plate (46) has a weight which is less than said total head weight; and

said total head weight is equal to the weight of said body (44) plus the weight of the selected sole plate (46).
A wood type golf club according to any preceding claim, wherein said body (44) has a hole (58) formed in said bottom portion (44a) to thereby reduce the weight of said body (44).
A wood type golf club according to any preceding claim, wherein said body (44) includes a hosel (52) with a bore (54) for receiving said one end of said shaft (56).
A wood type golf club according to any preceding claim, wherein said bottom portion (44a) of said body (44) has a bottom surface of compound curvature.
A method of making a wood type golf club having a desired swingweight, said wood type golf club including a head (42) attached to one end of a shaft (56), said head (42) having a total head weight which is used in calculating said swingweight, said method comprising the steps of:
providing a body (44) in said head (42) with a face portion (44b) for impacting a golf ball;

weighing said body (44) to insure that it has a weight which is within a preselected range that is less than said total head weight;

selecting a sole plate (46) from a plurality of sole plates formed of identical material and each having a majority of its weight concentrated around a perimeter thereof, the said plurality of sole plates having different weights such that the selected sole plate (46) has a weight which is equal to said total head weight minus the weight of said body (44); and

attaching said selected sole plate (46) to a bottom portion (44a) of said body (44).
The method of claim 13, further comprising the step of reducing the weight of said body (44) prior to said weighing step.
A correlated set of wood type golf clubs including at least two golf clubs of two different number designations wherein one of the number designations is higher than the other number designation, each golf club being a wood type golf club according to any one of claims 1 to 13, the head (42) of each golf club having a respective total head weight and the sole plate (46) of each respective golf club having a respective weight which is less than said respective total head weight, wherein:
the weight of the sole plate (46) on the golf club with said higher number designation is greater than the weight of the sole plate (46) on the golf club with said other number designation; and

both of the sole plates (46) are formed of identical material.
A correlated set of wood type golf clubs according to claim 16, wherein the golf club with said higher number designation is a number 3 wood and the golf club with said other number designation is a number 1 wood.