Diamond-like carbon coated golf club head

Abstract

A diamond-like carbon (DLC) coated golf club head primarily for reduction of friction between the hitting surface and the golf ball at impact. The DLC coating comes in two varieties including dehydrogenated DLC or hydrogenated DLC and is thinly applied between about 0.1 and 10 mum. The diamond particle size of individual diamond-like carbon molecules or crystals can be less than 0.1 mum, and preferably less than 1 nanometer. The DLC coating may be bonded to the golf club head or hitting surface using cathodic arc method or other applicable methods at temperatures of less than 200° C.

Description

[0001] The present application is a continuation-in-part application based on a U.S. patent application filed on Apr. 7, 1999, and having the Ser. No. 09 / 287,241.[0002] The present invention relates generally to improvements in the performance of a golf club, especially golf clubs used for distance. More specifically, the invention relates to the coating of the face or hitting surface of a golf club head with diamond-like carbon (DLC) to drastically reduce the frictional coefficient on the face of the golf club head, thereby increasing golf ball distance and accuracy.[0003] Golf is a very popular sport among people of all ages. As such, the golf equipment industry is constantly seeking to improve the design of golf equipment, especially golf clubs, to meet the demands of many golfers trying to improve their game or obtain a competitive edge over fellow golfers. There have been numerous attempts over the years to improve the performance of golf clubs and indeed, this continues today....

AI Technical Summary

Benefits of technology

[0017] The present invention pertains primarily to an improved golf club, more particularly, an improved golf club head. The golf club head of the present invention is comprised of a body having a hitting surface and a coating of diamond-like carbon (DILC). The diamond-like carbon (DLC) is used to coat a golf club head, particularly the hitting surface but including the lower surface, at a thickness of between about 0.1 and 10 .mu.m. Additionally, the diamond-like carbon (DLC) of the coating can have a grain size or diamond molecule size of less than 0.1 .mu.m. Larger diamond grain sizes can increase the friction between the golf club head hitting surface and the ball to less desirable levels compared to those of the present invention. Preferably, the present invention is intended to coat iron and / or titanium golf club heads, though golf club heads made from different materials or composites can also be used.

[0033] One reason that the use of diamond-like carbon (DLC) on the hitting surface of a golf club head is desirable, especially with respect to long game golf clubs, is that diamond-like carbon (DLC) has a very low frictional coefficient, i.e., 0.1 or less. This low frictional coefficient is comparable to teflon or other lubricants. Low friction between the hitting surface of a golf club head and the golf ball reduces heat and spin or angular momentum that a golf ball normally experiences after impact. Therefore, more forward or directional momentum is transferred from the golf club to the golf ball. In other words, the force behind a golf club swing is not wasted on angular momentum or generated heat.

[0034] Another advantage of the present invention is that to obtain a low frictional coefficient, the user is not required the use of a liquid lubricant as discussed in U.S. Pat. No. 5,885,171. The use of a liquid lubricant can be messy and if the golfer is not careful, the lubricant can get on the golfer's hands causing slippage on subsequent golf swings. Further, since the lubricant is not integrated into the golf club head, some lubricant will pass from the golf club head to the ball. This will cause the ball to fly unevenly or asymmetrically. The present invention provides a golf club head having a low friction coefficient (0.1 or less) on the hitting surface without the disadvantages associated with the use of lubricants.

[0035] Still another advantage of the present invention is that the diamond-like carbon (DLC) can be deposited on the golf club head or hitting surface at a relatively low temperature, i.e., less than 200.degree. C. This is significant because the properties of the base metal, i.e., substance that the golf club head is made of, will not be overheated causing alterations to the dimension or properties of the golf club head. Therefore, applying the diamond-like carbon (DLC) to a titanium or iron golf club head will not adversely affect the shape, relative strength or hardness of the golf club head. Further, the present invention addresses the issues presented in the previous discussion of U.S. Pat. No. 5,531,444 by providing a coating (DLC) that can be applied at a relatively low temperature. As such, the bore in the golf club head hozzle will not distort during the coating process. Additionally, since diamond-like carbon (DLC) is a relatively smooth substance, polishing of the respective golf club heads is minimized if not eliminated where the diamond-like carbon (DLC) has been applied.

Problems solved by technology

Though diamond has the highest modulus of rigidity, there are some basic problems with the use of diamond or diamond powder in general.

First, because the hitting surface is so hard, there is very little deformation of the club head creating a greater impact force.

Moreover, there are additional problems when a diamond-metal composite is used in that diamond is much harder than metal.

This unevenness will further increase the frictional force between the hitting surface of the club head and the golf ball.

Higher frictional force between the hitting surface and the golf ball is generally undesirable because unless the golf ball is perfectly hit, there is a greater likelihood of "hooking" or "slicing" a given shot.

These type of shots are normally undesirable for two reasons.

First, the distance that the golf ball travels is reduced because energy is wasted on angular momentum, i.e., spin, and heat generated from the increased friction.

Both of these energies reduce the desired forward momentum.

Second, since the desired direction is compromised, the next shot becomes more difficult.

Additionally, though back spin is desirable for some shots, even back spin will diminish the distance of a golf shot.

The preparation of diamond-metal composite (PCD) requires somewhat difficult and expensive modifications of a golf club.

Additionally, diamond-metal composite is expensive and the process of preparation is tedious making this option unaffordable to most golfers.

Moreover, the hitting surface of a club head containing a diamond-metal composite requires frequent polishing and / or grinding.

This additional work is time consuming and difficult to accomplish due to the presence of diamond.

In addition to issues surrounding rigidity, attempts have also been made to reduce the friction on golf club heads.

Though the goal of lowering the frictional coefficient is worthy, there are several disadvantages to the system disclosed in U.S. Pat. No. 5,885,171.

First, applying a liquid lubricant is messy and if the golfer is not careful, the lubricant can get on the golfer's hands causing slippage on subsequent swings.

Second, some lubricant will surely pass from the golf club head to the ball causing the ball to fly through the air unevenly.

Third, many golf shots necessarily require that the golf club strike the substrate or earth prior to hitting the golf ball.

Finally, it is inconvenient to be required to apply a liquid lubricant to a golf club prior to a golf shot, and further, be required to remove the same lubricant from the golf club head when completing a golf round.

However, to coat a metal golf club head with titanium nitride, high temperatures must be used.

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