Iron-type golf club head with stiffening rods

A golf club head having improved stiffness characteristics is disclosed herein. The golf club head, which preferably is an iron-type head, comprises a body with at least two stiffening rods extending between a top portion and a bottom portion or heel and toe portions of the body. The stiffening rods, when tightened, place pressure on one of the top portion and bottom portion, thereby stiffening that portion of the body. The stiffening rods are inserted into the body via internally threaded through-bores or ports, and when tightened, press against receiving cups extending from the top or bottom portions of the body into a rear cavity of the body. The present invention is also directed to a set of such golf club heads with stiffening rods in differing orientations within the heads depending on their loft angles.

Not Applicable

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an iron-type golf club head, and a set of such golf club heads, with optimized stiffness features. In particular, the golf club head of the present invention includes one or more stiffening structures that connect the bottom portion of the head to the top line of the head, thereby attenuating motion of at least one of the top and bottom portions of the head and reducing stress in the face upon impact with a golf ball.

Description of the Related Art

Golfers often prefer to use irons with thin, mostly unsupported faces in order to increase ball speed off the face, improve forgiveness, and generally improve their performance on the golf course. Unfortunately, open backed irons with thin, unsupported faces typically do not have the sound and feel desired by golfers. This problem can be fixed by fully enclosing the back of such a cavity back iron, but a fully enclosed cavity construction raises the iron's center of gravity and thus negatively affects the iron's mass properties and performance. Therefore, there is a need for a high performance iron with both a thin, unsupported face and an open cavity back with sufficient stiffness for desirable performance.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a golf club head with optimized stiffness characteristics, and a set of such golf club heads with top and bottom stiffnesses that vary across the set. The golf club heads preferably are irons, and include stiffening rods that extend between the top line and the bottom portion and preload at least a portion of the body of the golf club head, thus optimizing the trajectory of a golf ball upon impact. The invention disclosed herein can be used in connection with closed and open backed irons, and can also be used in connection with other types of golf club heads.

One aspect of the present invention is an iron-type golf club head comprising a body comprising a top portion, a bottom portion, a heel side, a toe side, a striking face, a rear cavity, at least one internally threaded through-bore in communication with the rear cavity, and at least one receiving cup extending into the rear cavity, and at least one stiffening rod comprising a threaded head portion sized to engage at the at least one internally threaded through-bore, a middle portion sized to extend between the at least one receiving cup and the at least one internally threaded through-bore, and an end portion sized to fit within the at least one receiving cup, wherein the at least one receiving cup is aligned with the at least one internally threaded through-bore along an axis that extends through the rear cavity, and wherein when the at least one stiffening rod is engaged with the body, tightening the at least one stiffening rod increases a stiffness of at least a portion of the body. In some embodiments, the at least one receiving cup may be affixed to the top portion, and the at least one internally threaded through-bore may extend through at least one of the heel side and the toe side, or may extend through the bottom portion.

In an alternative embodiment, the at least one receiving cup may be affixed to the bottom portion and the at least one internally threaded through-bore may extend through the top portion. In other embodiments, the at least one receiving cup may be integrally formed with the body. In some embodiments, the end portion may be tapered, and in others the at least one stiffening rod may be two stiffening rods, the at least one receiving cup may be two receiving cups, and the at least one internally threaded through-bore may be two internally threaded through-bores.

Another aspect of the present invention is a golf club head comprising a body comprising a top portion, a bottom portion, a heel side, a toe side, a front opening, a rear cavity, first and second internally threaded through-bores in communication with the rear cavity, and first and second receiving cups extending into the rear cavity from one of the top portion and the bottom portion, a face component comprising a striking face and a flange, and first and second stiffening rods, wherein the face component is sized to close the front opening, wherein each of the first and second stiffening rods comprises a threaded head portion sized to engage one of the first and second internally threaded through-bores, a middle portion sized to extend between one of the first and second receiving cups and one of the first and second internally threaded through-bores, and an end portion sized to fit within one of the first and second receiving cups, wherein the first receiving cup is aligned with the first internally threaded through-bore along a first axis extending through the rear cavity, and wherein the second receiving cup is aligned with the second internally threaded through-bore along a second axis extending through the rear cavity.

In some embodiments, the golf club head may be selected from the group consisting of an iron-type head, a putter-type head, a wood-type head, and a hybrid-type head. In other embodiments, the flange may extend away from a bottom portion of the striking face and the body may comprise a cutout sized to receive the flange. In still other embodiments, each of the body, face component, and first and second stiffening rods may be composed of a metal alloy.

Yet another aspect of the present invention is an iron-type golf club head comprising a metal body comprising a top portion, a bottom portion, a heel side, a toe side, a striking face, a rear cavity, at least one internally threaded through-bore in communication with the rear cavity, and at least one receiving cup extending from the top portion into the rear cavity, and at least one stiffening rod comprising an end portion disposed within the least one receiving cup, a threaded head portion at least partially disposed within and engaging the at least one internally threaded through-bore, and a middle portion extending between the end portion and the threaded head portion, wherein the at least one internally threaded through bore extends through at least one of the bottom portion, heel side, and toe side, wherein the at least one receiving cup is aligned with the at least one internally threaded through-bore along an axis that extends through the rear cavity approximately parallel with a rear surface of the striking face, wherein the middle portion extends approximately parallel with the rear surface of the striking face, wherein no portion of the at least one stiffening rod makes contact with the rear surface of the striking face, and wherein the at least one stiffening rod attenuates movement of at least one of the top portion and the bottom portion when the striking face impacts a golf ball.

In some embodiments, the at least one stiffening rod may be spaced from 0.136 inch to 0.210 inch from the rear surface of the striking face. In other embodiments, the at least one stiffening rod may be a solid metal rod, and wherein the end portion may be tapered. In still other embodiments, tightening the at least one stiffening rod may increase a stiffness of the top portion with respect to the rest of the body. In other embodiments, each of the body and at least one stiffening member may be composed of a material selected from the group consisting of stainless steel, carbon steel, and titanium alloy. In yet another embodiment, the at least one stiffening rod may comprise first and second stiffening rods, which may extend at an angle of less than 90° with respect to one another.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is generally directed to an iron-type golf club head with an adjustable stiffening system, which, by connecting the top portion of the club head to the bottom of the club head, creates the sound and feel of a closed cavity back iron while at the same time providing the desirable performance and mass properties of an open cavity back iron, including improved golf ball trajectories after impact. The present invention is also directed to a set of iron-type golf club heads with stiffening rods that have different orientations across the set. For example, higher lofted irons may have the stiffening rods oriented to provide stiffer top lines, while lower lofted iron may have the stiffening rods oriented to have stiffer bottom portions, and vice versa. Either way, the stiffening rods attenuate movement of the top line and/or bottom portion of the club head when the striking face of the club head impacts a golf ball.

In the preferred embodiment, shown inFIGS. 1-5, the iron-type golf club head10comprises a body20, a face component30having a striking face32and a flange or sole extension34, and two stiffening rods40,50extending at a greater than 90° angle to one another. The body20includes a top portion21, a bottom portion22, a heel side23, a hosel24, a toe side25, a rear cavity26defined by a rear surface33of the striking face32and the top and bottom portions21,22of the body20, and a cutout27in the bottom portion22sized to receive the sole extension34. The heel side23of the body20includes a heel-side port60proximate the bottom portion22, and the toe side25of the body20includes a toe-side port70proximate the bottom portion22, each of which have internal threading65,75and act as through-bores that communicate with the rear cavity26. The top portion21of the body20also includes a pair of receiving cups80,85extending from a central location of the top portion21into the rear cavity26, each of which has an axis90,95that is aligned with of one of the heel-side and toe-side ports60,70.

As shown inFIGS. 2-5, the stiffening rods40,50each comprise an externally threaded head portion42,52sized to engage the ports60,70, a middle portion44,54sized to extend through the rear cavity26of the body20approximately parallel with the rear surface of the striking face32, and a tapered end portion46,56sized to engage the receiving cups80,85. The head portion42,52also includes tool engaging features43,53such that a user can adjust the stiffening rods40,50with a screwdriver, Torq® wrench, or other tool known to a person skilled in the art. Each stiffening rod40,50is engaged with the body20by inserting the tapered end portion46,56, and middle portion44,54into one of the ports60,70until the tapered end portion46,56docks within a receiving cup80,85and the threads of the head portion42,52mate with the internal threads65,75of the port60,70. The stiffness of the top portion21can then be adjusted by tightening or loosening the stiffening rod40,50within the body20, such that more or less pressure is placed on the receiving cup80,85, and therefore the top portion21. Once the stiffening rod40,50is fixed within the body20and the top portion21has a desired stiffness with respect to the rest of the body20, the stiffening rod40,50can be permanently affixed to the body20with an adhesive such as Loctite® or by welding, brazing, soldering, or other means known to a person skilled in the art.

In another embodiment, shown inFIGS. 6-8, the iron-type golf club head10has all of the same features as the preferred embodiment, except that the ports60,70are disposed in the bottom portion22instead of in the heel and toe sides23,25of the body20and the stiffening rods50,60extend at an angle of 90° or less with respect of one another. Furthermore, in this embodiment, the face component30is not a partial face cup, such as the one shown inFIGS. 2-5, but instead is simply a face insert comprising a striking face32.

In yet another embodiment (not shown), the location of the ports60,70and receiving cups80,85may be inverted, such that the receiving cups80,85extend into the rear cavity26from the bottom portion22and the ports60,70extend into the rear cavity26from the top portion21. In this orientation, the stiffening rods40,50can be used to stiffen the bottom portion22instead of the top portion21. Yet another embodiment of the present invention is a set of these iron-type golf club heads10, each of which has its ports60,70and receiving cups80,85, and therefore stiffening rods40,50, in different orientations in the body20, such that the stiffness of the top portion21and bottom portion22differs depending on the loft of the iron-type golf club head10.

For each of the embodiments disclosed herein, the body20, the face component30, and the stiffening rods40,50may be formed from any suitable material, including but not limited to stainless steel, carbon steel, and titanium alloy. The ports60,70and receiving cups80,85preferably are integrally formed with the body20, but in other embodiments may be affixed to the body20by welding, brazing, soldering, or other means known to a person skilled in the art. As shown in the Figures, the stiffening rods40,50preferably are solid rods composed of a lightweight, strong metal material, though in an alternative embodiment one or both of the stiffening rods40,50may be a hollow tube or other structure made of a strong, lightweight metal material or composite material.

In all of the embodiments disclosed herein, at least the middle portion44,54of each stiffening rod40,50extends approximately parallel with the rear surface33of the striking face32without touching any portion of the striking face32. In fact, is preferable that no portion of either stiffening rod40,50makes contact with the rear surface33of the striking face32, even when the striking face32impacts a golf ball. Furthermore, each of the stiffening rods40,50is preferably located a distance D1of within 1 inch of the rear surface33of the striking face32. No portion of either stiffening rod40,50should be located outside of this 1-inch range; in fact, it is more preferable for each stiffening rod40,50to be located even closer to the rear surface33of the striking face32, preferably within 0.250 inch, and most preferably within a range of 0.136 inch to 0.210 inch from the rear surface33.

Though the invention disclosed herein is shown in connection with an iron-type golf club head, it may also be used to stiffen various structural elements of wood-type heads, hybrid-type heads, putter-type heads, and wedge-type heads.

The disclosure of each of U.S. Provisional Patent Application No. 62/424,223, U.S. patent application Ser. Nos. 14/812,971, 15/167,588, and 15/392,818, and U.S. Pat. No. 9,675,852 is hereby incorporated by reference in its entirety herein.