Golf club head manufacturing method

Abstract

Methods of bifurcating the material properties of golf club heads, and wedges in particular, are disclosed herein. The methods of the present invention preserve the bendability and feel of certain parts of the club heads, such as hosel regions, while selectively hardening and increasing the durability of other features, such as scorelines and texturing on the face.

Claims

1. A method comprising the steps of: manufacturing from a first, steel material a wedge-type golf club head comprising a top portion, a sole portion, a rear portion, a face, and a hosel; masking a portion of the hosel with a layer of clay material that is at least 0.020 inch thick; processing the face; hardening the head; removing the layer of clay material from the hosel; applying a groove to a transition region proximate the hosel; and finishing the head, wherein the step of removing the second material from the hosel occurs after the step of hardening the head, wherein the step of processing the face is selected from the group of steps consisting of polishing, texturing, and adding scorelines, and wherein the step of hardening the head comprises at least one process selected from the group consisting of carburization, nitriding, carbonitriding, nitrocarburization, quenching, flame hardening, and tempering.

2. The method of claim 1, wherein the first material has a first thermal conductivity value, wherein the second material has a second thermal conductivity value, and wherein the second thermal conductivity value is lower than the first thermal conductivity value.

3. The method of claim 1, wherein the step of processing the face comprises the step of adding scorelines, and wherein the step of adding scorelines comprises a process selected from the group of processes consisting of stamping, machining, and lasering.

4. The method of claim 3, wherein the step of processing the face further comprises the step of adding a secondary texture to the face proximate the scorelines.

5. The method of claim 4, wherein the secondary texture comprises a plurality of micro-features, and wherein each of the micro-features is disposed between a pair of adjacent scorelines.

6. The method of claim 5, wherein each of the micro-features extends at an angle with respect to the pair of adjacent scorelines.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a flow chart of a preferred method of the present invention.

(2) FIG. 2 is a side elevational view of a wedge of the present invention having excess material in its hosel region.

(3) FIG. 3 is a front, plan, partially transparent view of the wedge shown in FIG. 2.

(4) FIG. 4 is a front, plan, partially transparent view of the wedge shown in FIG. 2 with a tool removing the excess material.

(5) FIG. 5 is a front, plan, partially transparent view of the wedge shown in FIG. 2 without the excess material.

(6) FIG. 6 is a side elevational view of a wedge having a masking agent in its hosel region.

(7) FIG. 7 is a front elevational view of another wedge of the present invention.

(8) FIG. 8 is a cross-sectional view of the circled area in FIG. 7 undergoing laser processing.

(9) FIG. 9 is a flow chart of an alternative method of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(10) The present invention is directed to methods of selectively hardening some features of golf club heads, and wedges in particular, while preserving the bendability of other features.

(11) FIGS. 1-6 illustrate a first, preferred method of the present invention. In the first step, shown in FIGS. 1-3, a wedge head 10 comprising a sole region 12, top region 14, rear region 16, face 20, and hosel region 30 is manufactured from a metal alloy material, preferably stainless or carbon steel. In one version of the first step, the head 10 is integrally formed, forged, cast, or otherwise created with excess material 40 in the area of the head 10 where the material should remain soft to permit bending 110. The hosel region 30 preferably deforms more readily than the rest of the head 10 during bending, so as shown in FIGS. 2-3, the excess material 40 preferably is disposed around at least 20% of the hosel region 30, and may be disposed around up to 100% of the hosel region 30. This excess material 40 may be located elsewhere on the head 10 if the manufacturer deems it necessary for feel or other playability characteristics, such as the rear region 16 behind the face 20, where a softer, less strong, more flexible zone can change the primary mode of vibration and thus change sound and feel of the wedge head 10, but no matter where it is placed, it must remain on the head 10 until after heat treatment is completed.

(12) In an alternative version of the first step, shown in FIGS. 1 and 6, the head 10 is created 112 without excess material 40 on the hosel region 30, and a masking agent 50 is then applied to the area that should remain soft for bending 114, in this case the hosel region 30. The masking agent 50 preferably is a chemical layer, e.g., paint, but may be a physical barrier, e.g., tape or a material with low thermal conductivity, such as clay.

(13) Once the head 10 is manufactured and the hosel region 30 is protected as described above, the face 20 is processed 120 either to rough polish, fine polish, or textured prior to plating. This step 120 may also include the addition of scorelines 22 via stamping, machining, lasering, or other means known to a person skilled in the art, if scorelines 22 are not simultaneously added to the face 20 when the head 10 is initially formed, forged, cast, or machined.

(14) The head 10 is then subjected to a hardening treatment 130. The type of hardening treatment selected determines the minimum thickness of the excess material 40 placed around the hosel region 30 (or other regions that the manufacturer wishes to remain soft), as each hardening treatment affects the head 10 at different depths. In general, the thickness of the excess material 40 around the hosel region 30 should greater than than the depth of the hardening effect so that the hosel does not crack or crease during the bending process. For example, if the head 10 is hardened by carburization, which is most effective on lower carbon steels, the thickness of the excess material 40 should be greater than approximately 0.030-0.050 inch. If the head 10 is hardened by nitriding, a form of case hardening, then the thickness of the excess material 40 should be greater than approximately 0.020 inch. Nitriding can be performed either on raw (untreated) heads 10, or on heads 10 that have already been hardened by quenching or tempering for a greater effect. If the head 10 is hardened by carbonitriding or nitrocarburization, then the excess material 40 should be greater than 0.050 inch. If the head 10 is hardened by quenching, which generally is applied to higher carbon steels and is usually followed by tempering, the depth of the hardening effect depends on the rate of cooling during quenching, and may vary. The desired depth and length of the build-up or masked region can be determined either by testing or by FEA, which then can inform the required minimum thickness of the excess material 40.

(15) Once the hardening step 130 is completed, the excess material 40 or masking agent 50 is removed with a tool 60 via a mechanical process 140, illustrated in FIG. 4, and the head 10 can be finished 150 by any process desired by the manufacturer. When the head 10 is finished, the area 35 in the hosel region 30 originally covered by the excess material 40 or masking agent 50 (also known as the substrate) blends smoothly with the rest of the head 10, as shown in FIG. 5, but is much softer, and thus more ductile, than the rest of the head 10. In an alternative embodiment, one or more small grooves can be left at the transition region 34 between the area 35 originally covered by the excess material 40 or masking agent 50 and the rest of the head 10 to indicate to users the location of the softer, bendable region.

(16) In another method 200 of the present invention, illustrated in FIGS. 7-9, the wedge head 10 first is manufactured 210 as desired by a manufacturer (e.g., by casting, forging, forming, or the like), and then is prepared 220 for treatment to selectively improve the durability of critical areas of the face 20. This treatment involves the user of laser beams 70 to harden, for example, the ED region 24 of the scorelines 22, scoreline walls 26, or micro-features/texturing 28, each extending at an angle with respect to, and disposed between, adjacent scorelines 22 on the face 20, as shown in FIG. 7. As shown in FIG. 8, during this laser treatment 230, the laser follows the walls 26 and/or ED regions 24 of the scorelines 22, preferably at an angle a determined by the geometry of the region being treated to cover various features of the scorelines 22. Depending on the beam 70 width, several passes across the target may be necessary. Once the features have been hardened to the satisfaction of the manufacturer, the head 10 is finished 240 via any process desired by the manufacturer.

(17) From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.