Methods and apparatus for fabricating a putter club head

Abstract

A no-draft putter club head is formed using an investment casting process, wherein one or more critical surfaces of the club head—i.e., surfaces with contours that affect the visual appearance of the club head when viewed from above—are formed substantially parallel to the draw direction of the mold. The mold includes 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.

Description

FIELD OF THE INVENTION

The present invention relates, generally, golf club heads and, more particularly, to a method of fabricating a no-draft putter club head.

BACKGROUND OF THE INVENTION

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 FIGS. 1A and 1B, it is universal practice in the casting art to include tapered or angled surfaces (i.e., “draft”) within the mold cavity to facilitate removal of the finished part. Thus, mold 102 is configured such that surface 106 (and, consequently, matching surface 107 of part 104) is angled slightly to allow part 104 to be removed from mold 102 along a draw direction 108. Draw direction 108 is generally perpendicular to a separation line 105 defined by where the two mold halves meet.

As shown in FIG. 1B, by incorporating a draw into surface 106, there is adhesion, friction, and/or other mechanical interaction between surface 106 and surface 107 as part 104 is removed from mold 102. As depicted in FIG. 2, a draft angle 202 is suitably formed between surface 106 of the mold cavity and draw direction 108. In practice, angle 202 typically has a value between approximately 1.0 degree and 2.0 degrees.

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.

SUMMARY OF THE 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—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.

DRAWINGS OF THE DRAWINGS

The subject invention will hereinafter be described in conjunction with the appended drawing figures, wherein like numerals denote like elements, and:

FIGS. 1A and 1B depict the removal of a part from a mold cavity of the type having a draft;

FIG. 2 is a close-up of a draft angle as shown in FIG. 1;

FIGS. 3A and 3B depict the removal of a part from a mold cavity in accordance with the present invention;

FIG. 4 is a top view of a putter club head in accordance with one embodiment of the present invention; and

5A and 5B are isometric views of exemplary putter club heads in accordance with the present invention.

DETAILED DESCRIPTION

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 FIGS. 3A and 3B, a mold 302 in accordance with the present invention is configured such that one or more surfaces of the mold cavity, such as surface 306, are parallel to draw direction 108. Draw direction 108 of resulting mold 302 is generally perpendicular to the “parting line” or “separation line” 105 of the mold, i.e., the seam where two portions of the mold meet. The mold itself may be fabricated from any suitable material. In an exemplary embodiment used to form wax replicas in connection with an investment casting process, for example, mold 302 comprises an aluminum alloy.

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 FIG. 4. Club head 400 includes a club head body 402 and a hosel 404, wherein hosel 404 is configured to accept a shaft 406. Club head body 402 has a number of surfaces whose contours (which may be rectilinear, curvilinear, or a combination thereof) affect the visual appearance of the club head when viewed from above by a golfer during address. Such surfaces may be referred to herein as “critical surfaces.” In the illustrated club head 400, for example, body 402 includes a top surface (or “top rail” 414), a toe surface 410, and a heel surface 412. Each of these surfaces may be classified as critical surfaces. In addition, hosel 404 may also include one or more critical surfaces.

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. FIGS. 5A and 5B show isometric views of additional putter embodiments manufacturable using the methods of the present invention. Each of these club heads 400 include critical surfaces that are parallel to the draw direction of their respective molds. Such surfaces include toe surface 410, heel surface 412, top rail 414, and one or more surfaces of hosel 404. The putter club head designs shown in FIGS. 4, 5A, and 5B are merely presented for the purpose of example.

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.

Claims

1. A method for fabricating a putter club head comprising the steps of:

providing a mold having an internal cavity corresponding to a putter club head shape, wherein said cavity includes a set of surfaces parallel to a draw direction of said mold, said set of surfaces including at least one of a toe surface, a heel surface, a top rail surface, and a hosel surface;

injecting a wax material into said mold cavity to form a wax replica of said putter club head shape;

removing said wax replica from said mold cavity along a line parallel to said draw direction.

2. The method of claim 1, further including the steps of immersing said wax replica into a ceramic slurry and firing the resulting replica to form a ceramic shell mold.

3. The method of claim 2, further including the step of removing said wax replica from said ceramic shell mold.

4. The method of claim 3, further including the step of pouring a molten metal into said ceramic shell mold to form a finished part corresponding to said putter club head shape.