Weighted iron set

Abstract

The present invention generally relates to sets of iron golf clubs, and more particularly, to sets of iron golf clubs that are comprised of significant tungsten weighting to maximize the MOI about an axis through the CG that is parallel to the shaft axis.

Claims

1. A set of golf clubs comprising at least a first club head having a loft between about 15 and 25 degrees and a first club head mass, a second club head having a loft of between about 26 and 35 degrees and a second club head mass, and a third club head having a loft of about 36 degrees or greater and a third club head mass, the first club head having a first center of gravity and comprising: a body made of steel comprising a heel, a toe, a topline, a sole, a hosel defining a shaft axis, a front face insert and a back wall defining a first enclosed hollow interior, a toe weight member formed of tungsten and coupled into an upper toe portion of the first enclosed hollow interior that comprises about 10% to 30% of the first club head mass, wherein a center of gravity of the toe weight member is spaced at least about 28 mm from an axis parallel to the shaft axis that extends through the first center of gravity; and a heel weight member formed of tungsten, having a mass of 25 to 40 grams, and coupled in a lower heel portion of the first enclosed hollow interior, the heel weight member comprising about 5% to 20% of the first club head mass, wherein a center of gravity of the heel weight member is spaced at least about 28 mm from the axis parallel to the shaft axis that extends through the first center of gravity, and wherein the second club head has a second center of gravity and comprises: a second body made of steel comprising a second heel, a second toe, a second topline, a second sole, a second hosel defining a second shaft axis, a second toe weight member formed of tungsten and coupled to a second upper toe portion of the second body that comprises about 10% about 30% of the second club head mass, wherein a second center of gravity of the second toe weight member is spaced at least about 28 mm from a second axis parallel to the second shaft axis that extends through the second center of gravity; and a second heel weight member formed of tungsten, having a mass of between 15 to 40 grams, and coupled in a second lower heel portion of the second body, the second heel weight member comprising about 5% to 20% of the second club head mass, wherein a second center of gravity of the second heel weight member is spaced at least about 28 mm from the second axis parallel to the second shaft axis that extends through the second center of gravity.

2. The set of golf clubs of claim 1, wherein the first toe weight member and the second toe weight member are at least 30 grams.

3. The set of golf clubs of claim 1, wherein the first club head has a Moment of Inertia about the axis parallel to the shaft axis that extends through the first center of gravity of greater than about 230 kg-mm.sup.2.

4. The set of golf clubs of claim 3, wherein the second club head has a Moment of Inertia about the second axis parallel to the second shaft axis that extends through the second center of gravity of greater than about 230 kg-mm.sup.2.

5. The set of golf clubs of claim 1, wherein the first club head has a blade length of about 74 mm to 85 mm.

6. The set of golf clubs of claim 5, wherein the second club head has a blade length of about 74 mm to 82 mm and is less than the blade length of the first club.

7. The set of golf clubs of claim 1, wherein the first club head has a blade length of about 74 mm to 85 mm and the center of gravity of the toe weight member and the center of gravity of the heel weight member are both spaced a distance of at least about 30% of the blade length from the axis parallel to the shaft axis that extends through the first center of gravity.

8. The set of golf clubs of claim 1, wherein the first club head has a blade length of about 74 mm to 85 mm and D1 plus D2 is greater than about 70% of the blade length, wherein D2 is a distance between the center of gravity of the toe weight member and the axis parallel to the shaft axis that extends through the first center of gravity and D1 is a distance between the center of gravity of the heel weight member and the axis parallel to the shaft axis that extends through the first center of gravity.

9. A set of golf clubs comprising at least a first club head having a loft between about 15 and 25 degrees and a first club head mass, a second club head having a loft of between about 26 and 35 degrees and a second club head mass, and a third club head having a loft of about 36 degrees or greater and a third club head mass, the first club head having a first center of gravity and comprising: a body made of steel comprising a heel, a toe, a topline, a sole, a hosel defining a shaft axis, a front face insert and a back wall defining a first enclosed hollow interior, a toe weight member formed of tungsten, having a mass of greater than 65 grams, and coupled into an upper toe portion of the first enclosed hollow interior that comprises about 10% to 30% of the first club head mass, wherein a center of gravity of the toe weight member is spaced at least about 28 mm from an axis parallel to the shaft axis that extends through the first center of gravity; and a heel weight member formed of tungsten, having a mass of between 10 to 20 grams, and coupled in a lower portion of the first hosel, the heel weight member comprising about 5% to 20% of the first club head mass, wherein a center of gravity of the heel weight member is spaced at least about 28 mm from the axis parallel to the shaft axis that extends through the first center of gravity; and a second body made of steel comprising a second heel, a second toe, a second topline, a second sole, a second hosel defining a second shaft axis, a second toe weight member formed of tungsten, having a mass of greater than 65 grams, and coupled to a second upper toe portion of the second body that comprises about 10% about 30% of the second club head mass, wherein a second center of gravity of the second toe weight member is spaced at least about 28 mm from a second axis parallel to the second shaft axis that extends through the second center of gravity; and a second heel weight member formed of tungsten and coupled in a second lower portion of the second hosel, the second heel weight member comprising about 5% to 20% of the second club head mass, wherein a second center of gravity of the second heel weight member is spaced at least about 28 mm from the second axis parallel to the second shaft axis that extends through the second center of gravity.

10. The set of golf clubs of claim 9, wherein the first club head has a Moment of Inertia about the axis parallel to the shaft axis that extends through the first center of gravity of greater than about 230 kg-mm.sup.2.

11. The set of golf clubs of claim 10, wherein the second club head has a Moment of Inertia about the second axis parallel to the second shaft axis that extends through the second center of gravity of greater than about 230 kg-mm.sup.2.

12. The set of golf clubs of claim 9, wherein the first club head has a blade length of about 74 mm to 85 mm and the second club head has a blade length of about 74 mm to 82 mm.

13. The set of clubs of claim 9, where the first club has a Moment of Inertia about the axis parallel to the shaft axis that extends through the first center of gravity to blade length ratio that is between about 3.1 kg-mm and 3.5 kg-mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a back view of an iron according to the prior art;

(2) FIG. 2 is a perspective view of the iron in FIG. 1;

(3) FIG. 3 is a front view of a long iron according to the present invention;

(4) FIG. 4 is a back view of a long iron according to the present invention;

(5) FIG. 5 is a perspective view of the iron in FIG. 4;

(6) FIG. 6 is a front view of another long iron according to the present invention;

(7) FIG. 7 is a front view of a mid iron according to the present invention; and

(8) FIG. 8 is an exploded view of another embodiment of a long iron according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(9) As illustrated in the accompanying drawings and discussed in detail below, the present invention is directed to an improved set of iron-type golf clubs, wherein the clubs have tungsten weight members that form a significant portion of the club heads' mass and are positioned to maximize the Moment of Inertia of the iron about an axis that is parallel to the shaft axis and extends through the center of gravity.

(10) Referring to FIGS. 1 and 2, a prior art iron 10 has a heel 12, a toe 14, a hosel 16, a back cavity 18 a top line 20 and a sole 22. The iron is comprised of two main components, the main body 24 and the weight members 26. The iron includes a shaft axis SA and an axis, APSA.sub.CG, that is parallel to the shaft axis and extends through the center of gravity CG. The main body 24 is usually formed from steel. For at least the long irons and mid irons, the weight members 26 include a toe weight member 28 and a heel weight member 30 that are formed from tungsten. Thus, the main body 24 will have a specific gravity of about 7-8 g/cm3 and the weight members 26 will have a specific gravity of about 14-20 g/cm3.

(11) As shown, the distance from the center of gravity for the heel weight member to axis APSA.sub.CG is substantially greater than the distance of the toe weight member from the axis APSA.sub.CG.

(12) As shown in FIG. 3 the present invention includes a set of irons that have a Blade Length (BL) of each club within the set. The BL is defined at the length from the hosel axis (HA) intersection with the ground plane to the end of the toe. The irons also have a Toe Height (TH) that progressively increases through the set. Thus, the TH of the mid iron is greater than the TH of the long iron and the TH of the short iron is greater than the TH of the mid iron and the long iron. The TH is defined as the maximum length from the leading edge to the top of the toe in the plane parallel to the face plane and perpendicular to the scorelines. Preferably, the TH increases by about at least 0.3 mm per club, and most preferably at least 0.4 mm per club. Also, the TH preferably increases at least 1 mm per club (or about 4 degrees of loft) for the short irons and only 0.3-0.6 mm per club for the long and mid irons.

(13) Furthermore, the irons in the set have a scoreline width (SLW) that progressively decreases in length from long irons to short irons in the set and can have a scoreline to toe width (SLTW) that progressively increases from long irons to short irons within the set. More particularly, in a preferred embodiment, the SLW decreases by at least about 0.1 mm per club (or per 4 degrees of loft). Thus, the SLW for the long iron is greater than the SLW for the mid iron and the SLW for the mid iron is greater than the SLW for the short iron.

(14) Each of the irons has a center of gravity, CG, a hosel length, HL, and a shaft axis, SA, that is also defined by the hosel bore. The clubs according to the present invention are optimized for a maximum moment of inertia, MOI, about an axis that extends parallel to the SA and extends through the CG, APSA.sub.CG. The CG of the club is preferably very close to the center of the score lines, that is ½ SLW from the score line edges. In a more preferred embodiment, the long irons have a CG that is at least 0.45*SLW from the heel edge of the scorelines. In an even more preferred embodiment, the mid irons also have a CG that is at least 0.45*SLW from the heel edge of the scorelines.

(15) Referring to FIGS. 4 and 5, a long iron 50 according to the present invention has a loft between about 15 and 25 degrees. The long iron 50 is preferably made of steel and comprises a heel 52, a toe 54, a topline 60, a sole 62, a hosel 56 that defines the shaft axis SA, and a back wall 58. The long iron 50 also includes a toe weight member 68 formed of tungsten that is coupled to an upper toe portion of the back wall 58. Preferably, the toe weight member 68 comprises between about 10% to 30% of the long iron's mass and the center of gravity of the toe weight member CGW1 is spaced a distance D2 that is at least about 28 mm, and more preferably, about 30 mm from the axis that is parallel to the shaft axis that extends through the iron's center of gravity, APSA.sub.CG. The long iron 50 includes a heel weight member 70 that is also formed of tungsten. The heel weight 70 is preferably coupled a lower portion of the hosel 56 or the lower-heel portion of the back wall 58. Preferably, the heel weight member 70 comprises about 5% to 20% of the long iron's mass and the center of gravity of the heel weight member CGW2 is spaced a distance D1 that is at least about 28 mm, and more preferably, about 30 mm from the axis APSA.sub.CG. Preferably, D1 and D2 are approximately equal, i.e., they are within a few millimeters of each other, and more preferably, D1 and D2 are within about 10% of each other. Further, D1 and D2 are both greater than about 30% of the blade length BL.

(16) In order to maximize the MOI about the APSA.sub.CG, it is important to incorporate a significant amount of mass at the upper-toe location and lower-heel location. Thus, the toe weight member 68 and the heel weight member 70 should be constructed out of tungsten having a specific gravity of greater than 14 g/cm.sup.3. More preferably, the weight members are formed of a tungsten having a specific gravity of 17 g/cm.sup.3 or greater. The greater the specific gravity of the weight members, the further the CGW1 and CGW2 can be from the APSA.sub.CG.

(17) In the preferred embodiment of the long iron and the mid irons, the mass of the toe weight member 68 is about 30 grams or greater and is located more than about 28 mm, and more preferably, about 30 mm from the APSA.sub.CG. The mass of the heel weight member 70 is less for the long irons than in the mid iron in the most preferred set. However, the toe weight member 68 and the heel weight member 70 have about the same mass for the mid irons. Moreover, the distance D1 and the distance D2 are approximately equal, i.e., they are within 3 to 4 millimeters of each other, for the long irons and the mid irons. Still further, the distance D1 plus the distance D2 is greater than about 70%, and more preferably, about 75% of the blade length BL.

(18) Tables I (mass properties) and II (club properties) provide exemplary, non-limiting dimensions for the various measurements of clubs according to the Example of the invention shown in FIGS. 4 and 5. It is fully intended that all of the dimensions set forth below can be adjusted such that the overall objective of the individual irons is met.

(19) TABLE-US-00001 TABLE I Club Number 2 3 4 5 6 7 8 9 P loft 17 21 24 27 30 34 38 42 46 Total 234 234 242 249 254 263 270 278 283 Mass (g) Toe W 32 32 36 33 30 27 (g) Heel W 14 14 24 26 30 32 (g) D1 33 33 34 34 35 35 D2 33 33 34 34 35 35

(20) TABLE-US-00002 TABLE II Club Number 2 3 4 5 6 7 8 9 P Blade Length 78 78 78 78 78 78 78 78 78 (mm) Toe Height 52 52 52 53 53 53 54 55 56 (mm) Scoreline 53 53 53 53 53 52 52 52 52 Width (mm) Scoreline 17 17 18 18 18 18 18 19 19 to Toe (mm) Hosel Length 63 63 63 63 63 64 68 72 75 (mm) Sole Width 19 19 18 18 18 17 17 16 15 (mm)

(21) As shown in FIGS. 6-7 and set forth in the Tables III and IV below, another embodiment of the present invention includes a hollow long iron 100 and a hollow mid iron 200. In FIG. 6, the long iron 100 includes a body member 110, heel 112, a toe 114, a hosel 116 and a sole 118. The iron body 110 includes an insert aperture 120 and a hollow portion 122. A face insert, not shown, is welded to the insert aperture 120 to enclose the hollow portion 122. Both the body member 110 and the face insert are preferably formed of steel and have a specific gravity of about 7 to 8 g/cm.sup.3. The face insert is preferably formed from a high strength steel and has a thickness of less than about 2 mm. Inside the hollow portion 122, a tungsten toe weight member 124 and a tungsten heel weight member 126 are located proximate an upper portion of the toe 114 and a lower portion of the heel 112, respectively, to create a high moment of inertia about the APSA.sub.CG.

(22) As shown in Table III below, the long irons preferably have a mass of about 220 grams to 250 grams. In the long irons 100, the toe weight member 124 preferably has a mass of about 30 to 55 grams, and preferably about 10% to 30% of the club head mass. Preferably, the toe weight member 124 mass increases with each club by about 5 grams per club. The heel weight member 126 is preferably about 25 grams to 40 grams, and preferably comprises about 5% to 20% of the club head mass. Preferably, the heel weight members decrease by about 1 or 2 grams per club. More preferably, the tungsten mass of the toe weight member 124 and the heel weight member 126 combined are at least about 25% of the total club head mass and at least about 15% of the total club head solid volume. More particularly, the toe weight member 124 and the heel weight member 126 comprise about 30% of the total mass and more than about 20% of the total solid volume. Preferably, the toe weight member 124 has greater mass than the heel weight member 126. Preferably, the toe weight member and the heel weight member are formed of tungsten have a specific gravity of greater than 14 g/cm.sup.3, and more preferably, greater than or equal to about 17 g/cm.sup.3. Moreover, in order to maximize the MOI about the APSA.sub.CG, the toe weight member 124 is coupled into the upper toe portion of hollow portion 122 and the heel weight member 126 is coupled to the lower heel portion of the hollow portion 122 such that the center of gravity of the weight members 124 and 126 are spaced a distance of at least about 28 mm, and more preferably, about 30 mm from the APSA.sub.CG. Further, the toe weight member 124 is coupled into the upper toe portion of hollow portion 122 and the heel weight member 126 is coupled to the lower heel portion of the hollow portion 122 such that the center of gravity of the weight members 124 and 126 are spaced a distance, D2 and D1 respectively, of at least about 30% of the blade length from the APSA.sub.CG. Moreover, D1 plus D2 is preferably greater than about 70%, and more preferably, about 75% of the blade length.

(23) TABLE-US-00003 TABLE III Club Number 2 3 4 5 6 7 8 9 P loft 17 20 23 26 29 33 37 41 45 Total 234 240 245 252 260 267 274 282 286 Mass (g) Toe W 38 45 50 55 61 60 61 63 (g) Heel W 34 32 31 31 20 20 (g) D1 30 30 31 32 32 32 D2 31 31 31 32 32 33 33 33

(24) TABLE-US-00004 TABLE IV Club Number 2 3 4 5 6 7 8 9 P Blade Length 78 78 78 78 78 78 78 78 78 (mm) Toe Height 52 52 53 53 54 54 55 55 56 (mm) Scoreline 53 53 53 53 53 52 52 52 52 Width (mm) Scoreline 17 17 18 18 18 18 18 19 19 to Toe (mm) Hosel Length 62 63 64 65 66 67 68 69 70 (mm) Sole Width 19 19 19 19 18 17 17 16 15 (mm)

(25) As shown in FIG. 7 and as set forth in Tables III and IV above, a set of irons according to the present invention includes a mid iron 200 that includes a body member 210, heel 212, a toe 214, a hosel 216 and a sole 218. The iron body 210 includes an insert aperture 220 and a hollow portion 222. A face insert, not shown, is welded to the insert aperture 220 to enclose the hollow portion 222. Both the body member 210 and the face insert are preferably formed of steel and have a specific gravity of about 7 to 8 g/cm.sup.3. Inside the hollow portion 222, a tungsten toe weight member 224 and a tungsten heel weight member 226 are located proximate an upper portion of the toe 214 and lower portion on the heel 212, respectively, to create a high moment of inertia about the APSA.sub.CG. More preferably, the toe weight member 224 of the mid iron is located a distance D2 from the APSA.sub.CG that is greater than about 28 mm, and more preferably, about 30 mm and is approximately the same or greater than the distance D2 for the long irons. The heel weight member 226 is located a distance D1 from the APSA.sub.CG that is greater than about 28 mm, and more preferably, about 30 mm and is preferably located a distance D1 from the APSA.sub.CG that is greater than or equal to D1 for the long irons. For the mid irons, D1 and D2 are, preferably, approximately equal and D1 plus D2 is preferably greater than about 70%, and more preferably, about 75% of the blade length.

(26) As shown in Table III above, the mid irons 200 preferably have a mass of about 250 grams to about 270 grams. In the mid irons 200, the toe weight member 224 preferably has a mass of about 40 to about 60 grams, and preferably, comprises about 10% to 30% of the overall club head mass. Preferably, the mass of the toe weight member 224 increases with an increase in club loft within the set or remains approximately equal. The heel weight member 226 is preferably about 15 grams to about 40 grams, and preferably, comprises about 5% to 20% of the overall club head mass. Preferably, the mass of the heel weight members 226 decreases with an increase in club loft within the set or remains approximately equal. Preferably, the tungsten mass of the toe weight member 224 and the heel weight member 226 combined are at least about 15% of the total club head mass and at least about 10% of the total club head solid volume. More particularly, the toe weight member 224 and the heel weight member 226 comprise about 20% to 25% of the total mass and more than about 10% of the total solid volume. Preferably, the toe weight member 224 has greater mass than the heel weight member 226. Preferably, the toe weight member and the heel weight member are formed of tungsten have a specific gravity of greater than 14 g/cm.sup.3, an more preferably greater than or equal to about 17 g/cm.sup.3.

(27) Referring to FIG. 8, another embodiment of the present invention is a set of golf clubs comprising at least a long iron having a loft between about 15 and 25 degrees and a first club head mass, a mid iron having a loft of between about 26 and 35 degrees and a second club head mass, and a short iron having a loft of about 36 degrees or greater and a third club head mass. The long iron, for example, is preferably formed from steel and comprises a body 1200 that comprises a heel 1212, a toe 1214, a topline 1220, a sole 1218, and a hosel 1216. A front face insert 1210 and a back wall 1224 form a hollow cavity 1226 therebetween.

(28) Preferably, the iron body 1220 is cast with the main cavity 1226 and the hosel cavity 1232. The front face insert 1210 is preferably stamped from a high strength sheet metal and is welded to the body after a toe weight member 1228 is secured with in the hollow cavity 1226. A heel weight member 1230 is inserted into the face side of the hosel cavity 1232 and then a hosel cover member 1234 is welded to the front portion of the hosel 1216 to secure the heel weight member 1230 within the hosel cavity 1232.

(29) The toe weight member 1228 is formed of tungsten and is coupled to an upper toe portion of the hollow cavity 1226. Preferably, as set forth in Table V below, the toe weight member 1228 is greater than about 65 grams and comprises about 10% to 30%, and more preferably about 20% to 30% of the long iron club head mass. The long iron head 1200 further comprises the heel weight member 1230 that is also formed of tungsten. The heel weight member 1230 is about 10 to 20 grams and comprises about 5% to 20% of the overall club head mass. Preferably, the heel weight member 1230 is coupled into the hosel cavity 1232 formed in the front, lower portion of the hosel 1216. In this embodiment, the heel weight member 1230 is preferably secured in the hosel cavity 1232 by a cover member 1234 that forms at least a front portion of the hosel 1216. The toe weight member 1228 and the heel weight member 1230 are both formed of tungsten and preferably have a specific gravity of greater than 14 g/cm.sup.3, and more preferably greater than about 17 g/cm.sup.3. The hosel cover member is preferably formed of a nickel alloy having a specific gravity of between about 8 g/cm.sup.3 and about 14 g/cm.sup.3.

(30) In the preferred set, the mid iron has the same or similar construction as the long iron, and thus, similarly comprises a steel, hollow body with a heel, a toe, a topline, a sole, and a hosel. As set forth in Table V below, the toe weight member for at least one of the mid irons is also formed of greater than 65 grams of tungsten and comprises about 20% to 30% of the mid iron head mass.

(31) In the set of irons according to this embodiment the present invention, the iron 1200 is preferably formed of steel and has a specific gravity of about 7 to 8 g/cm.sup.3. The tungsten toe weight member 1228 and a tungsten heel weight member 1230 are again located proximate an upper portion of the toe 1214 and lower portion on the heel 1212, respectively, to create a high moment of inertia about the APSA.sub.CG. More preferably, the toe weight member 1228 of the iron is located a distance D2 from the APSA.sub.CG that is greater than about 28 mm, and more preferably, about 30 mm. The heel weight member 1230 is located a distance D1 from the APSA.sub.CG that is greater than about 28 mm, and more preferably, about 30 mm. For the iron 1200, D1 and D2 are, preferably, approximately equal and D1 plus D2 is preferably greater than about 70%, and more preferably, about 75% of the blade length.

(32) The club heads according to the present invention have high MOI about the APSA.sub.CG. Because they have such large tungsten weight members, the MOI about the APSA.sub.CG is greater than about 230 kg-mm.sup.2, and more preferably greater than about 250 kg-mm.sup.2, for the long iron and mid iron. Still further, the irons in the preferred set as presented in Tables V and VI below are not oversized. That is, the blade length is less than about 82 mm. Thus, the MOI about the APSA.sub.CG to blade length ratio is very high. More particularly, the MOI about the APSA.sub.CG to blade length ratio is greater than about 3 kg-mm, and more preferably, between about 3.1 kg-mm and 3.5 kg-mm.

(33) Moreover, because the mid irons and the long irons are hollow, the Center of Gravity is relatively deep. More particularly, the Center of Gravity depth from the face center, CGzFC, is preferably greater than 6 mm for all of the irons. In a preferred embodiment, the CGzFC can be around 8 mm for the long irons. Preferably, the CGzFC is between about 1/15 and about 1/10 of the blade length for the long iron.

(34) TABLE-US-00005 TABLE V Club Number 3 4 5 6 7 8 9 P loft 19 22 25 28 31 35 39 43 Total Mass (g) 239 247 254 261 268 274 284 286 Body Mass (g) 85 86 87 118 261 267 278 280 Face Mass (g) 58 58 58 56 Toe W (g) 67 74 77 73 Heel W (g) 14 15 18 Steel Mass % 60 58 57 67 W Mass % 34 36 37 28

(35) TABLE-US-00006 TABLE VI Club Number 3 4 5 6 7 8 9 P Blade Length 81 81 81 80 80 80 80 80 (mm) Toe Height 31 31.5 32 32.3 32.7 33.3 34 34.5 (mm) Scoreline 54.5 54.3 54.1 54 53.8 53.6 53.3 53.1 Width (mm) Sole Width 16.8 16.3 15.8 15.3 14.8 14.65 14.5 14.35 Center (mm)

(36) 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 modifications and embodiments which would come within the spirit and scope of the present invention.