Patent Application
20050045305
The present invention relates, generally, golf club heads and, more particularly, to a method of fabricating a no-draft putter club head.
A golfer's ability to properly line up a ball with the club head to produce the desired ball path is largely a function of the various visual cues provided to the golfer by the club head during and after address. This is particularly the case with putting, where the golfer's address and stroke direction are highly influenced by psychological and visual factors.
It is desirable for many of the surfaces of a putter, particularly those surfaces that have contours visible to the golfer from above during address, to be square and aligned either perpendicular or parallel to the top rail. Traditional casting processes, however, inhibit the formation of such surfaces.
For example, referring to
As shown in
As mentioned above, it is desirable for a putter club head to include surfaces that, when viewed from above the club head, are perpendicular or parallel to the draw direction of the mold cavity used to manufacture the club head. Because traditional molding techniques prevent the casting of such a design without draft (even in relatively modern investment wax processes) it is customary to machine various surfaces of the club head after casting to give the desired visual appearance. Such machining is time consuming and greatly adds to the cost of the golf club.
The present invention generally provides a method for casting a no-draft putter club head using an investment casting process, wherein one or more critical surfaces of the club head—i.e., surfaces with contours affect the visual appearance of the club head when viewed from above—are formed substantially parallel to the draw direction of the mold.
A method in accordance with one embodiment of the present invention includes providing a mold having an internal cavity corresponding to a putter club head shape, wherein the cavity includes a set of surfaces substantially parallel to the draw direction of the mold. This set of surfaces may include, for example, a toe surface, a heel surface, a top rail surface, and/or a hosel surface. A wax material is suitably poured or injected into the mold cavity to form a wax replica of the putter club head shape. The wax replica is then removed from the mold cavity along a line parallel to the draw direction. A putter club head fabricated in accordance with this method is characterized by precisely-shaped surfaces which provide subtle alignment aids to the golfer at address.
The subject invention will hereinafter be described in conjunction with the appended drawing figures, wherein like numerals denote like elements, and:
5A and 5B are isometric views of exemplary putter club heads in accordance with the present invention.
The present invention generally provides a method for casting a no-draft putter club head using an investment casting process, wherein one or more critical surfaces of the club head (e.g., the top rail, the toe, the heel, and/or the hosel) are formed substantially parallel to the draw direction of the mold.
In general, as shown in
Notwithstanding the fact that mold 302 of the present invention includes a surface 306 that is parallel to surface 307, part 304 may be easily removed along draw direction 108 without experiencing significant sticking, friction, or the like. Because the present invention does not require the incorporation of a draft or taper into one or more critical surfaces of the club head, the club head body, as cast, is substantially square when viewed from above, and is less likely to require machining.
In general, a method of fabricating a putter club head in accordance with one embodiment of the present invention involves an investment-casting or “lost-wax” process—a processing method which is desirable due to its cost effectiveness and precise dimensional control. Conventional investment casting techniques known to those skilled in the art will not be described in detail herein. For more information regarding such processes, see, e.g., SOPCAK, HANDBOOK OF LOST WAX OR INVESTMENT CASTING (1986), which is hereby incorporated by reference. Furthermore, while the present invention is described in the context of an investment casting process, it will be understood the present invention is not so limited.
An exemplary method for manufacturing a golf club head begins with the creation of a die or mold 302 having a club head shape formed therein, for example, a club head such as that shown in top view in
It can be seen that each of these surfaces is formed substantially parallel to the draw direction of the mold, which in the illustrated embodiment is generally perpendicular to line 416 defined by top rail 414.
After a suitable mold 302 has been provided, a wax material (in liquid or paste form) is then injected into the mold (or “die”) and allowed to cool to form a solidified wax pattern or “replica.” In one embodiment, the wax is a paste wax having a melting temperature of about 100 degrees C. In an alternate embodiment, however, the wax has a melting temperature of about 200 degrees C.
The wax material in the mold cavity is then suitably cooled. This cooling may be accomplished through convection (e.g., air cooling of the mold), conduction, radiation, or a combination thereof. The wax form is allowed to cool to a temperature at which it may be handled, i.e., removed from mold 302. In one embodiment, the wax is a paste wax that is allowed to cool for approximately 60 seconds to 100 seconds (preferably about 80 seconds) before being removed from the mold. In accordance with another embodiment of the present invention, the wax form is allowed to cool for approximately 10 seconds to 30 seconds (preferably about 20 seconds).
The resulting solidified wax pattern is then removed from the die by pulling it out along the draw direction 108. In conventional casting operations, the lack of draft on critical surfaces would prohibit easy removal of the finished part. In accordance with the present invention, however, the use of wax in conjunction with a metallic mold as described above results in a wax form that can be removed from the mold along the draw direction and, at the same time, include one or more critical surfaces (e.g., toe surface, heel surface, top rail, etc.) that are parallel to the draw direction.
After the wax replica is formed, a number of such wax patterns may be attached to a central wax stick or “sprue” to form a cluster of wax patterns. The replica is immersed one or more times into a suitable ceramic slurry, allowed to dry, then immersed in a bed of suitably fine sand to form a shell mold around the solidified wax. The solidified wax replica is melted or otherwise removed from the inner chambers of the shell mold. The shell mold is then baked in a suitable oven to harden the shell and remove any residual. At this point, one or more hardened shell molds have been formed. These shell molds serve as the basis for metal casting of the actual club head.
Although the invention has been described herein in conjunction with the appended drawings, those skilled in the art will appreciate that the scope of the invention is not so limited. Modifications in the selection, design, and arrangement of the various components and steps discussed herein may be made without departing from the scope of the invention as set forth in the appended claims.
