1. Field of the Invention
The present invention relates to golf clubs, and more particularly to hollow golf clubs. Still more particularly, the present invention relates to a hollow golf club wherein the head, the shaft, or the head and the shaft thereof is selectively pressurized either above or below atmospheric pressure.
2. Description of the Related Art
Golf clubs are conventionally composed of a head having a face for striking a golf ball and a shaft connected with the head at a neck of the head. The shaft includes a grip for the golfer to adeptly hold and adroitly swing the golf club to thereby strike the golf ball during a game of golf. The shaft is usually in the form of a hollow rod and is constructed of metal, although other materials and constructions can be used. The head has conventionally three basic forms: a "wood" which has usually a metallic construction with a more-or-less bulbous configuration and a large area face; an "iron" which has a thin metallic construction and a large area face; and a "putter" which has a thin metallic construction and a small area face. Golf club heads have face shapes, face surface contours and face angles (relative to the shaft) which provide selected ball striking features that are of particular utility depending upon the golfer's play situation as the game unfolds. Accordingly, a golfer typically has a set of golf clubs having a variety of head types.
Golfers are eternally trying to perfect their game, whereby the least number of strokes are expended to complete a round of golf. While a golfer's score may partly be dependent upon skill and luck, the quality of the golf clubs used are crucial to a low score. Over the years, many golf club designs have been forwarded which claim to improve a golfer's score simply on the basis of improved equipment.
One type of golf club concept that has been forwarded is to place a pressurized fluid into the head in order to improve the golfer's score, as follows. U.S. Pat. No. 5,263,713 to Taylor et al, dated Nov. 23, 1993, discloses a hollow golf club head having therein a pressurized silicon oil which is intended to increase the size of the "sweet spot" of the face and increase the drive range of a struck golf ball. The pressures disclosed are extremely high (the low pressure value disclosed being on the order of 5,000 pounds per square inch (psi) gauge, and the high pressure value disclosed being on the order of 30,000 psi). It is courteously submitted that this pressure range involves an excessive pressure which would seem to be inherently dangerous. United Kingdom Patent Application 2,247,628, published on Mar. 11, 1992, discloses a hollow head golf club having a pressurized gas therein, the gas pressure being set anywhere from 1 to 250 atmospheres (ie, from zero to 3,675 psi, wherein 1 atmosphere is defined as 14.7 psi absolute).
While the above two patents usefully describe pressurizing a golf club head to thereby effect an advantageous quality change thereto, they are silent as to other possibilities which may be effected to provide a more complete range of advantageous quality changes to the golf club by means of selective adjustment of pressure therewithin, by means of providing an internal pressure below atmospheric, and by means of selectively pressurizing the shaft.