Putter

Abstract

A putter club having a relatively hard face insert supported by at least one dampening layer is disclosed. The putter club also has an internal weight positioned in line with the center of gravity of the club. The putter club has a body and a sole plate wherein the density of the body is substantially higher than the density of the sole plate. A vibration dampening system for a golf club is also disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of co-pending U.S. application Ser. No. 10/704,774, filed Nov. 10, 2003.

FIELD OF THE INVENTION

This invention generally relates to golf clubs, and more particularly relates to putter golf clubs.

BACKGROUND OF THE INVENTION

Golf clubs, particularly the clubs used on and around the greens, have long been developed to improve the touch and feel for the golfers. Conventional approaches to improve touch and feel include modifying the grip, the shaft or the strike face of the clubs. In one example, U.S. Pat. No. 6,231,458 B1 discloses an insert on the strike face that affects the rebound of the golf ball at impact with the strike face. The '458 patent further discloses a dampening layer located behind the insert that dampens the vibrations caused by the impact and improves the touch and feel feedback to the golfers. The amount of feedback can be controlled by the amount of contact between the face insert and the dampening layer. To improve touch and feel, the insert is made from a relatively soft tellurium copper alloy.

In another example, U.S. Pat. No. 6,238,303 B1 discloses a putter club having a user-replaceable face insert. The insert is selected to have different weight, texture and hardness. The user can choose a particular insert for the club to match the club's putting characteristics to the green's conditions. The insert can be fabricated from titanium, graphite, polytetrafluoroethylene (PTFE), copper, brass, plastics, aluminum, carbon steel, stainless steel among others.

However, the prior art does not contemplate a putter that has a striking face with properties that are uniquely different from other parts of the club.

SUMMARY OF THE INVENTION

Hence, the present invention is directed to a putter club having a face insert.

The present invention is also directed to a putter club having a relatively hard face insert supported by at least one dampening layer.

The present invention is directed to a system of vibration dampeners for a golf club.

The present invention is also directed to a putter club having an internal weight positioned in line with the center of gravity of the club.

The present invention is also directed to a putter club with a body and a sole plate wherein the density of the body is substantially higher than the density of the sole plate.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

FIG. 1 is a perspective exploded front view of the putter in accordance with the present invention showing the insert and the putter body;

FIG. 2 is a perspective back view of the putter in FIG. 1;

FIG. 3 is a perspective bottom view of the putter in FIG. 1;

FIG. 4 is exploded view of the putter in FIG. 1 showing the sole plate and the bottom of the putter body; and

FIG. 5 is a front view of the putter of FIG. 1 showing the insert and the hitting face.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Putter club head 10 in accordance with an embodiment of the present invention is illustrated in FIGS. 1-5. Club head 10 comprises front 12, back 14, top 16, sole 18, heel 20, toe 22 and hosel 24. Hosel 24 is attachable to one end of a shaft and a grip is attached to the shaft at the opposite end. In a preferred embodiment, club head 10 is a mallet type putter and has face insert 26 attachable to the club head body, designated collectively as reference number 28, to form front 12. As shown, insert 26 has a shape that is substantially the same as front 12 and is dimensioned to fit inside the perimeter of face 12. A gap 40 is defined on face 12 around insert 26, as illustrated in FIG. 5. The thickness of insert 26 can be constant, or can vary. As shown, insert 26 is relatively thick, except in the vicinity of the hosel where insert 26 is thinner. The present invention, however, is not limited to the size and shape of the insert illustrated and described herein. Insert 26 can be attached to body 28 by any conventional means, including welding, threaded fasteners, adhesives, etc., discussed below. The loft angle of front 12 is preferably about 0° to about 6°, and more preferably about 4°.

As best shown in FIGS. 1 and 2, top 16 may have any contour, shape or aesthetic designs. Top 16 comprises front region 32 proximate front 12 and a mallet-shaped extension. The mallet-shaped extension has concaving top surface 34 surrounded by border region 36. For additional distinctiveness, concaving surface 34 has a plurality of score lines 38. The present invention, however, is not limited to mallet putter clubs or to any particular aesthetic designs.

Sole plate 18 is preferably made separate from body 28 and is attached thereto by any conventional means, such as threaded fasteners, as best shown in FIGS. 2 and 4. As illustrated, body 28 is hollow; however, it is understood that the present invention is not limited to hollow club heads. Weight 30 is attachable to sole 18 to alter the mass of the club head. In one embodiment, weight 30 is added to club head 10 when the length of the shaft is less than about 35 inches, and preferably when the shaft length is about 33 inches to about 34 inches. In one embodiment, when the shaft length is about 35 inches, weight 30 is zero. When the shaft length is about 34 inches, weight 30 is about 10 grams, and when the shaft length is about 33 inches, weight 30 is about 20 grams. Sole plate 18 may also include indicia on the outside surface to indicate the shaft length, as shown in FIG. 3.

In accordance to one aspect of the present invention, weight 30 is positioned at a location directly behind the center of gravity of putter 10. When putter 10 strikes a golf ball at its center of gravity, weight 30 would line up on an imaginary line connecting the center of gravity of the club to the center of gravity of the ball. More preferably, the center of gravity of weight 30 lines up with this imaginary line. In other words, weight 30 is positioned such that it lines up with the center of gravity of the club in the X, Y and Z directions. Such disposition of weight 30 advantageously minimizes vibration when the putter strikes a ball.

In accordance to another aspect of the present invention, preferably disposed between insert 26 and body 28 is a first dampening layer X. Dampening layers in putter golf clubs are fully disclosed in commonly owned U.S. Pat. No. 6,231,458 B1, which is incorporated herein by reference in its entirety. Suitable dampening materials include any materials, such as polymeric materials, that posses the appropriate tangent of delta to absorb vibrations generated by impacts with golf balls and to improve the touch and feel of the club. Optional screws, as illustrated in FIG. 2, may also be used to attach insert 26 to body 28. These optional screws can also be used to hold insert 26 tightly against body 28. Suitable dampening materials include, but are not limited to, silicone materials, such as Stock No. GE281 from General Electric, and foamed rubbers or elastomers.

A second dampening layer Y can be provided in gap 40 between insert 26 and the rest of face 12 to further dampen vibration. Preferably, the second dampening layer is made from silicone material. Furthermore, a third dampening layer Z can be provided between weight 30 and sole 18, and preferably third dampening layer Z is made from the same material as the first dampening layer.

In accordance to one aspect of the present invention, insert 26 is made from a substance that is relatively hard, i.e., having high hardness measurement. In one example, the insert is made from a grade 303 stainless steel commercially available from Monstanstahl AG of Germany (hereinafter SS 303 DE), and the body is made from other commercial grade 303 annealed stainless steel and the sole plate is made from commercial grade aluminum alloy 6061. The tables below summarize the chemical make-up and mechanical properties of the different parts of club head 10.

TABLE 1
Chemical Compositions
	Carbon	Chromium	Nickel	Nitrogen	Sulfur	Iron
Insert 26 (SS 303 DE)	0.15%	17%-19%	8%-10%	—	0.15% min.	Remaining
Body 28 (SS 303)	0.15%	17%-19%	8%-10%		0.15% min	Remaining
	Copper	Silicone	Manganese	Magnesium	Chromium	Aluminum
Sole 18 (Aluminum	0.28%	0.6%	—	1.0%	0.20%	Remaining
alloy 6061)

TABLE 2
Mechanical Properties
	Tensile	Yield	Elongation
	Strength	Strength	before	Hardness	Density
	(kpsi)	(kpsi)	break	(Brinell)	(lb/in3)
Insert 26	109	71	40%	183	0.289
(SS 303 DE)
Body 28	75-90	30-40	35%-50%	262	0.289
(SS 303)
Sole 18	8 & 40	18 & 45	25% & 12%	30 & 95	0.098
(Aluminum
alloy 6061)

Brinell hardness is measured by forcing a hard steel or carbide sphere of a specified diameter under a known applied force for a known duration of time. The Brinell hardness number is obtained by dividing the force of the load used in kilogram by the actual surface area of the indentation caused by the sphere in square millimeters. The Brinell hardness number, therefore, has a unit similar to that of pressure. For aluminum and other soft metals, the applied force used is 500 kg. For the harder irons and steels, the applied force used is 3000 kg. The time period that the force is applied is about 10-15 seconds. Preferably, hardness tests are conducted under the ASTM E-10 standard.

The mechanical properties listed above for stainless steel 303 represent typical properties for stainless steels 303 that have been annealed, and the mechanical properties listed for SS 303 DE are the properties for the stainless steel 303 produced by Monstanstahl AG, which is the preferred material for insert 26. Although insert 26 and body 28 can be made from the same material, e.g., stainless steel 303, insert 26 is softer (lower hardness) but has higher yield strength and tensile strength than body 28.

Two sets of numbers are given for aluminum alloy 6061. The first set corresponds to the annealed alloy and the second set corresponds to the alloy that had been tempered. Both alloys are suitable for sole 18. The annealed aluminum alloy 6061 is more preferred due to its softness for ease of manufacturing. Additionally, aluminum alloy 6061 has a density that is about 3 times less than the density of stainless steel 303, and when used in the sole plate can move the center of gravity of the putter upward to a more desirable position.

The inventor of the present invention believes that a combination of a relatively hard hitting face provided by the hard insert with more than one dampening layer supporting the hard insert provides the putter with better touch and feel.

While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.

Claims

1. A putter comprising a club head having a body comprising a front portion and a back portion, wherein the front portion has an insert supported by a dampening layer and the insert has a Brinell hardness of at least about 150.

2. The putter of claim 1, wherein the Brinell hardness of the insert is lower than a Brinell hardness of the body by less than 100.

3. The putter of claim 1, wherein a tensile strength of the insert is higher than a tensile strength of the body.

4. The putter of claim 1, wherein a yield strength of the insert is higher than a yield strength of the body.

5. The putter of claim 1, wherein the insert has a Brinell hardness of less than about 200.

6. The putter of claim 2, wherein the difference in Brinell hardness is at least about 10.

7. The putter of claim 6, wherein the difference in Brinell hardness is at least about 25.

8. The putter of claim 7, wherein the difference in Brinell hardness is at least about 50.

9. The putter of claim 1, wherein the back portion comprises a mallet type extension.

10. The putter of claim 1, further comprising a sole plate attachable to the body and made from a material with a density lower than a density of the body.

11. The putter of claim 10, wherein the sole plate is made from a non-ferrous material.

12. The putter of claim 11, wherein the sole plate is made from aluminum alloy.

13. The putter of claim 10, wherein the density of the body is at least about twice the density of the sole plate.

14. The putter of claim 13, wherein the density of the body is at least about three times the density of the sole plate.

15. The putter of claim 1, further comprising a weight member positioned within the body such that a center of gravity of the putter coincides with the weight member.

16. The putter of claim 15, wherein a center of gravity of the weight member is positioned approximate the center of gravity of the putter.

17. The putter of claim 1, wherein the dampening layer is located on a back surface of the insert.

18. The putter of claim 1, further comprising a second dampening layer visible on the front portion and positioned around the insert.

19. The putter of claim 1, further comprising a third dampening layer positioned between a weight member and a sole plate attached to the body.

20. The putter of claim 19, wherein the third dampening layer attaches a weight member to the sole plate.