Abstract:
A metal wood type golf club head having a c-shaped aerodynamic configuration formed in the bottom surface adjacent a rear surface and having an open end extending forwardly toward the ball striking face in combination with a skid surface.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to golf club heads and in particular to a metal wood type golf club head having an improved aerodynamic surface on the bottom rear of the sole. 
     Wood and metal wood type golf club heads are used for hitting a golf ball a longer distance and are usually used for the first shot of a given golf hole from a tee position. Fairway clubs of the same type are also used &#34;through the green&#34; on a golf hole to obtain maximum distance in the direction of or onto a putting surface. The distance the ball travels is determined by the club head speed at the moment of impact and the weight of the club head in accordance with well known laws of physics. Typical wood and metalwood golf club of this type have aerodynamic surfaces, but conventional shapes create substantial air turbulence, which, in turn, causes adverse erratic movement and aerodynamic drag that reduces the club head speed generated for a given force developed by a golfer for a particular golf swing. 
     Over the years, club heads have been developed with aerodynamic shapes to increase club head speed by reducing the aerodynamic drag of the club head as it is swung. Prior art examples of these type of golf club heads include U.S. Pat. Nos. D275,412 to Simmons, 2,550,840 to Milligan, 3,997,170 to Goldberg, 4,065,133 to Gordos, 4,900,029 to Sinclair, 5,203,565 to Murray et al, and 5,467,989 to Good et al. as well as my own U.S. Pat. Nos. 4,828,265, 4,930,783, 5,004,241, 5,193,810, 5,221,086 and 5,511,786 among others. 
     SUMMARY OF THE INVENTION 
     The present invention represents an improvement over known prior art wood type golf club heads by providing an aerodynamic surface on the bottom sole adjacent the rear edge of the club head, which produces greater club head speed when the club head is swung. This aerodynamic surface reduces undesirable air turbulence which causes aerodynamic drag and creates a smoother, laminar type air flow around the club head. A golf club using this improvement permits a golfer to hit longer and straighter golf shots for a given applied swing force. The aerodynamic structure also creates increased aerodynamic stability of the club head resulting in increased control of the club head position during the swing, especially at impact, thereby producing more consistent golf shots. 
     The golf club head of the present invention includes a c-shaped aerodynamic slot formed on the bottom sole surface of the club head. In a preferred embodiment, a metal wood type golf club head, having a smooth upper surface and sloped side walls, includes a c-shaped aerodynamic slot located adjacent the rear surface on the bottom surface or sole which generally follows the contours of the peripheral edges of the club head between the sole and the side walls. The open end of the c-shaped slot faces forwardly toward the front ball striking face of the club. The club head may also include a raised sole plate on the bottom surface having a spacer wall which also provides an aerodynamic effect and creates a skid structure enabling the club to skim across the ground surface when the club head is swung to hit a golf ball. 
     In another preferred embodiment, a venturi slot is provided between the c-shaped slot and the rear surface of the club head to further direct air flow adjacent the rear surface of the club head where most turbulence occurs. 
     The aerodynamic surfaces of the club head create aerodynamic effects which minimize turbulence and increase laminar air flow to reduce drag resulting in a more stable club head with higher speed for a given application of swing force by the golfer. 
     A primary object of the present invention is to provide a golf club head having an improved aerodynamic surface on the bottom sole adjacent the rear of the club head to substantially reduce drag and improve swing stability. 
     Another object is to provide a golf club head which increases club head speed and lift by concentrating air flow near the rear surface of the club head where turbulence occurs to reduce drag on the club head as it is swung. 
     Other objects and advantages of the present invention will become apparent in the following description of the preferred embodiments taken into conjunction with the accompanying drawings which are incorporated in and constitute a part of the specification and together with the description, serve to explain the principles of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a bottom view of an aerodynamic golf club head in accordance with the present invention. 
     FIG. 2 is a bottom perspective view of the golf club head of FIG. 1. 
     FIG. 3 is a rear elevational view thereof. 
     FIG. 4 is an end elevational view thereof. 
     FIG. 5 is a sectional view taken along the lines 5--5 of FIG. 3. 
     FIG. 6 is a bottom view of a second embodiment of an aerodynamic golf club in accordance with the present invention. 
     FIG. 7 is a bottom perspective view of the golf club head of FIG. 6. 
     FIG. 8 is rear elevational view thereof. 
     FIG. 9 is a bottom view of a third embodiment of the present invention. 
     FIG. 10 is a bottom view of a forth embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The detailed embodiments of the present invention are disclosed herein. It should be understood, however, that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, the details disclosed herein are not to be interpreted as limited, but merely as the basis for the claims and as a basis for teaching one skilled in the art how to make and/or use the invention. 
     FIGS. 1-5 show a first embodiment of a golf club head 100 in accordance with the present invention. The golf club head 100 is conventional in shape, except for the aerodynamic surfaces and includes a hosel 112, heel 114, toe 116, upper surface 118, rear surface 120, ball striking face 122 and bottom surface 124. The bottom sole 124 includes a skid member 126 which extends outwardly from the bottom sole 124 and is separated therefrom by a spacer wall 128. A c-shaped aerodynamic slot 130 is formed on the bottom surface 124 and faces forwardly with open ends 132 of the c-shaped slot 130 being toward the ball striking face 122. Preferably, the c-shaped slot 130 extends from a point adjacent the interface of the bottom surface 124 and rear surface 120 across approximately two thirds of the distance to the ball striking face 122. 
     The aerodynamic slot 130 catches air just behind the ball striking face 122 and directs it toward the rear surface 120 within the curved walls of the c-shaped slot 130 of the club head 100. The air is expelled rearwardly out of the slot to minimize turbulence and reduce drag as the club head 100 is swung. At the same time, the skid 126 and spacer walls 128 also serve to direct the air flow rearwardly to increase laminar flow in that area of the club head 100. 
     FIGS. 6, 7, and 8 show a second embodiment of a golf club head 200 in accordance with the present invention. This club head 200 is similar to that described to the club head hereinabove and includes a hosel 212, heel 214, toe 216, upper surface 218, rear surface 220, upper toe 230, side walls 222, a ball striking face 224, bottom surface 225, a skid 226 and a spacer wall 228 separating the skid 226 from the bottom surface 225. A c-shaped aerodynamic slot 230 is formed on the bottom surface 225 adjacent the rear surface 220. The open end of the slot 230 faces forwardly toward the ball striking face 224. 
     The slot 230 is formed with a venturi opening 232 which extends rearwardly and upwardly into the rear surface 220 creating an additional air channel to direct the air flow. 
     FIG. 9 shows another embodiment of the present invention. A golf club head 300 is similar to the club head described in FIGS. 1-5 and includes a bottom surface 325, a side surface 327 and an aerodynamic slot 330 which is offset in the direction of the toe 316 of the club head 300. 
     FIG. 10 shows another embodiment similar to FIG. 9. A golf club head 400 and includes a bottom surface 425, a side surface 427 and an aerodynamic slot 430 which is offset in the direction of the heel 414 of the club head 400. 
     It will be appreciated that the offset aerodynamic slots of FIGS. 9 and 10 allow greater club head speed at the heel or toe selectively in order to more effectively accommodate the swing characteristics of a particular golfer, whether left-handed or right-handed. 
     While various preferred embodiments have been shown and described, it will be understood that there is no intent to limit the invention by such disclosure, but rather, is intended to cover all modifications and alternate constructions falling within the spirit and scope of the invention as defined in the appended claims.