DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] With reference to FIG. 1, an iron 10 comprises a shaft 12 with a grip 14 and a head 16. The head 16 is connected by a hosel 18 to the shaft 12 in a conventional manner. Similarly, the grip 14 is attached to the shaft 12 in a conventional manner. The head 16 comprises a toe portion 20, heel portion 22, sole portion 24 and top ridge portion 26. The finished club height 28 progressively decreases from long irons, e.g. 2, 3, 4, to short irons, e.g. 8, 9, PW. The front striking face 30, which contains a primary striking zone or sweet spot 32, is suitably scored with grooves.

[0034] FIG. 2 illustrates a back view of the iron club head 16. A peripheral mass 36 is formed on the rear surface 34 of the club head 16, defining a rear cavity 38. Artisans will appreciate that cavity back or perimeter weighted clubs enjoy a larger sweet spot or hitting area than conventional forged irons. As shown in FIG. 2, a cantilevered mass 40 extends from the bottom sole portion 24 toward the top ridge portion 26 within the rear cavity 38. As will be described more fully below, the cantilevered mass 40 is variably positioned along the bottom sole portion 24 below and behind a primary striking zone or sweet spot 32 of the striking face 30. The location of the cantilevered mass 40 below and behind the sweet spot lowers the center of gravity of the club which aids the golfer in placing the center of gravity of the club head below the center of gravity of the golf ball at the moment of impact, producing a properly airborne and solidly hit ball having a high trajectory.

[0035] As shown in FIG. 3 (side view), the cantilevered mass 40 is spaced apart from the rear surface 34 of the club head. It is to be appreciated that spacing the cantilevered mass 40 apart from the rear surface 34 provides forgiveness for off-center hits. In other words, golfers may still produce acceptable shots despite striking the ball in a location on the striking face 30 other than the center or sweet spot 32. The cantilevered mass 40 tapers from a thickness that is greatest at the sole portion 24 toward the top ridge portion 26.

[0036] With reference to FIGS. 5A, 5B, and 5C, for an iron set consisting of 2, 3, 4, 5, 6, 7, 8, 9, PW, and SW, the cantilevered mass 40 is disposed in one of three positions along the bottom sole portion 24 between the heel portion 22 and the toe portion 20. The cantilevered mass is progressively moved from the low heel area (FIG. 5A) on long irons (2-4), to a middle position (FIG. 5B) on the middle irons (5-7), to a higher position toward the toe (FIG. 5C) on the short irons (8-SW). It is to be appreciated that varying the position of the cantilevered mass 40 varies the center of gravity for the club, and therefore, provides for optimum trajectory and launch angle for each golf shot. In one preferred embodiment, the cantilevered mass 40 is located approximately 1.00 inches from the heel portion in the long irons (FIG. 5A), approximately 1.187 inches from the heel portion in the middle irons (FIG. 5B), and approximately 1.375 inches from the heel portion in the short irons (FIG. 5C).

[0037] In a preferred embodiment, each iron club head 16 is comprised of a cryogenically treated steel. Artisans will appreciate that cryogenic treatment of metals, including steel, results in greater hardness and tensile strength than untreated metals. For example, cryogenic treatment of standard 17-4 pH steel results in a steel which is harder and stronger than both 6-4 titanium and alpha maraging steel. Because of the increased hardness and strength of cryogenically treated steel, the striking face thickness FT of the club head is thinner than conventional irons. In one embodiment, the striking face thickness FT is reduced from 0.145 inches to 0.130 inches. This reduction in face thickness FT results in a reduction of approximately 15 grams in striking face mass. This additional mass that is not present in the striking face is relocated other regions of the club head in order to enhance overall performance. Preferably, this additional mass is located in the peripheral mass and the cantilevered mass, resulting in a lower center of gravity and enhanced performance.

[0038] During the cryogenic treatment process, the temperature of the golf club head is slowly and gradually lowered to approximately −300 degrees Fahrenheit in a nitrogen gas-filled chamber. As the steel is supercooled, molecular movement is decreased and the molecules join together more tightly. As the temperature is gradually increased, the molecules remain closer together in a more uniform and dense formation, resulting in a stronger and harder substance. It is to be appreciated that a cryogenically treated steel golf club head produces greater energy transfer which translates into added distance in golf shots.

[0039] In a preferred embodiment, the following reduced face thicknesses FT in the primary striking zone or sweet spot 32 are present:

[0040] 2-5 iron: 0.125-0.135 inches,

[0041] 6-7 iron: 0.120-0.125 inches, and

[0042] 8-PW: 0.115-0.120 inches.

[0043] For a preferred set of irons made in accordance with the present invention, the following dimensions are provided: 1

[0044] 2

[0045] With reference to FIG. 6 and FIG. 7, a wood type golf club 100 comprises a shaft 112 with a grip 114 and a head 116. The head 116 is connected by a hosel 118 to the shaft 112 in a conventional manner. Similarly, the grip 114 is attached to the shaft 112 in a conventional manner. The head comprises a hollow body 136 having an inner cavity delimited by a sole portion 124. Additionally, the head 116 includes a toe portion 120, heel portion 122, and a crown portion 126. The front striking face 130, which contains a primary striking zone or sweet spot 132, is suitably scored with grooves.

[0046] FIG. 8 illustrates a sole view of the club head 116. The sole portion 124 of the club head contains a pocket 150 in which a weight chip 154 is disposed. In a preferred embodiment, the weight chip 154 is welded to the sole portion 124 inside the pocket 150 by a plurality of welds 160 disposed in a weld groove 158, as shown in FIG. 8A. While other means of fastening the weight chip to the sole portion, such as adhesives, fasteners and pressing, are contemplated, it is to be appreciated that welding provides a stronger and more permanent bond between the club head 116 and the weight chip.

[0047] In a preferred embodiment, the club head 116 is comprised of a cryogenically treated steel. As set forth above, it is to be appreciated that cryogenically treated steel provides greater hardness and tensile strength than conventional club head materials. Because of the increased hardness and strength of cryogenically treated steel, the striking face thickness of the club head is thinner than conventional metal woods. In a preferred embodiment, the primary striking zone or sweet spot of the striking face is between 0.130 and 0.135 inches. The reduction is striking face thickness results in a reduction of the mass of the striking face. In one embodiment, the additional mass not used in the thinner club face, is distributed around the sole portion and crown portion of the club head in order to enhance overall weighting and performance. In another embodiment, the additional mass is not distributed about the club head, resulting in a club having reduced mass.

[0048] In a preferred embodiment, the weight chip is made out of tungsten having a mass of between 25 and 45 grams, preferably, 35 grams. Alternately, the weight chip is made of another metal which has a density greater than the density of the cryogenic steel of the club body. As shown in FIG. 9, the presence of the tungsten weight chip in the sole portion of the club head lowers the overall center of gravity CG of the club head versus a conventional center of gravity CG₁. It is to be appreciated that the lower center of gravity promotes more consistent distance and accuracy from off-center hits as well as a higher trajectory. Artisans will appreciate that the lower center of gravity promotes solid contact with balls which are in undesirable locations, such as long grass, dirt, and tight lies, i.e. where little or no grass is present under the ball. For a preferred set of woods made in accordance with the present invention, the following dimensions are provided: 3

[0049] 4

[0050] The invention has been described with reference to the preferred embodiment. Modifications and alterations will occur to others upon a reading and understanding of the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.