Abstract:
A golf club includes a club head that has one or more air passages extending from its front face to its rear face, so that when the club is swung in a ball-striking action air in the path of the club head is transferred from a pressurized zone on the head front face through the air passages into a low pressure wake area behind the club head. The air transfer action minimizes resistance to club movement, so as to contribute to a faster club head speed and a longer ball travel.

Description:
FIELD OF INVENTION 
       [0001]    This Invention relates to golf clubs and particularly to an improved golf club head that will enable the golfer to swing the golf club so that the club head has a greater velocity (as compared with the velocity of a generally similar conventional golf club). The present invention relates to club head velocity enhancement. 
       DESCRIPTION OF THE RELATED ART 
       [0002]      FIGS. 1 and 2  of the attached drawings show a golf club having a club head of generally conventional construction (or shape). During a golf ball-striking event the club head is swung in an arc from a starting position in which the club head is above and slightly behind the golfer&#39;s head. The club head travels in an arc angularly downwardly and then in front of the golfer&#39;s upright body so as to come into forcible contact with a stationary golf ball located at or slightly above ground level. 
         [0003]    The club head continues the arcuate movement to an elevated point away from the golfer&#39;s body, while the golf ball is propelled forwardly from the ball-striker face of the club head. The golf ball travel distance is generally proportional to the club head velocity at the moment when the club head makes contact with the ball; i.e. a higher club head velocity at the ball contact moment will generally produce a desirably longer ball travel. 
         [0004]    One obstacle to a higher club head velocity is the air resistance or turbulence associated with arcuate travel of the club head from the starting (elevated) position to the ball contact position (at or near ground level).  FIG. 1  of the attached drawings shows generally how the club head disturbs the air as it travels in a right-to-left direction. The airstream flow lines (with arrows) are relative to the club head, which is moving in an absolute sense, so that air in area  20  on the front face of the club is pressurized to force the air outwardly and then around the club head side surfaces. At some point (or plane) the air separates from the club head to form a low pressure wake area  24  behind the trailing surface  16  of the club head. In  FIG. 1  of the drawings the air separation point (or plane) is designated by numeral  11 . 
         [0005]    The low pressure wake area exerts a suction effect on the club head, to reduce the club head velocity. At the same time the pressurized area  20  proximate to the front face  14  of the club head also has a retarding (or reducing) effect on the club head velocity. To sum up, the suction effect of suction wake area  24  and the pressurizing effect in area  20  are additive to provide a total air resistance contributing to an undesired loss of club head speed. The present invention concerns an air passage system designed to reduce the total air resistance that contributes to an undesired loss of club head speed. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention involves a golf club head having one or more air passages extending from the front face of the club head to the trailing face of the club head, so that during a ball-striking event some of the air in front of the club head is transferred through the passage(s) to the wake area behind the club head. This transfer of air partially reduces the air pressure in front of the club head while at the same time raising the air pressure in the low pressure wake area behind the club head. The net effect of this air transfer is to reduce the air resistance to club head movement, thereby promoting a faster club head speed and greater golf ball travel distance. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]      FIG. 1  is a top plan view of a conventional golf club head, showing the relative air flow pattern around the club head during a golf ball-striking event, i.e. while the golfer is swinging the golf club to drive the golf ball down the fairway. 
           [0008]      FIG. 2  is a front view of the  FIG. 1  golf club head, taken in a direction looking toward the club head front face  14 . 
           [0009]      FIG. 3  is a top plan view of a golf club head embodying the present invention. 
           [0010]      FIG. 4  is a front view of the  FIG. 3  golf club head. 
           [0011]      FIG. 5  is a sectional view of the  FIG. 3  golf club head, taken on line  5 - 5  in  FIG. 3 . A conventional golf ball is shown in phantom, in front of the club head. 
           [0012]      FIG. 6  is a top plan view taken in the same direction as  FIG. 3 , but showing another form that the invention can take. 
           [0013]      FIG. 7  is a front view of the  FIG. 6  construction. 
           [0014]      FIG. 8  is a sectional view taken on line  8 - 8  in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    Before describing the golf club of the present invention, it is believed that a better understanding of the invention can be realized by first describing the conventional prior art golf club, as shown, e.g., in  FIGS. 1 and 2 . The conventional golf club comprises a club head  10  attached to a conventional shaft  12 . The club head has a ball-striker front face  14 , a convex curvilinear rear face  16 , and side surfaces  17  extending rearwardly from the peripheral edges of front face  14  to merge smoothly with curvilinear rear face  16 . As shown in  FIG. 1 , side surfaces  17  taper in a direction from the front face to the rear face, so as to promote (as much as possible) a smooth air flow relative to the club head. The flow is “relative” since the club head is moving in a right-to-left direction, while the air is essentially stagnant except for air that is momentarily displaced by passage of the club head. Numeral  22  generally designates the relative air stream components, particularly the displaced air stream elements. 
         [0016]    Air in zone  20  proximate to the club head front face  14  is pressurized by the advancing club so as to offer some resistance to continued club head motion. Air in the path of the club head is displaced outwardly by pressurized air in zone  20  to points beyond the peripheral edges of front face  14 , as indicated by numeral  22 A. The displaced air than collapses back toward the club head side surfaces  17  to flow, as much as possible, along those surfaces. Numeral  22 B designates the collapsing air. 
         [0017]    At some point the air separates from side surfaces  17  to form a low pressure wake area  24  proximate to curvilinear rear face  16 . Numeral  11  designates generally the imaginary separation plane, i.e. the point(s) where the boundary air layer on surfaces  17  can no longer control or hold the main air stream on the club surface. In actuality, the rear surface  16  of the club head is moving so fast in a right-to-left direction that the air cannot collapse toward the club head centerline  19  rapidly enough to keep pace with club head movement. Rear face  16  tends to produce a vacuum in wake area  24 , thereby generating turbulence that prevents the collapsing air from attaching to surface  16 . 
         [0018]    It will be seen that resistance to club head motion in a right-to-left direction is provided by the pressurized air condition in zone  20  plus the low pressure suction condition in turbulent wake area  24 . The result is an undesired loss of club head speed. 
         [0019]      FIGS. 3 through 5  shows a club head of the present invention designed to reduce air resistance to club head movement. The club head is similar to the conventional club head depicted in  FIG. 1  except that an air passage means is provided in the club head to transfer air from pressurized zone  20  to wake area  24 . The effect is to reduce the pressure in zone  20  and simultaneously increase the air volume in wake area  24  (thereby reducing the suction effect on club rear face  16 ). 
         [0020]    The air passage means comprises a first slot-shaped air passage  30  having an entrance opening proximate to upper edge  32  of the club front face  14  and a second slot-shaped air passage  30  having an entrance opening proximate to lower edge  34  of the club front face  14 . Front face  14  can be defined by a metal place  28  having a relatively hard ball-striker surface (face). Each air passage  30  extends from front face  14  entirely through the club head body to form an exit opening  33  in curvilinear rear face  16 . Motion of the club head in a right-to-left direction provides the motive force for transferring air from pressurized zone  20  through air passages  30  into depressurized wake area  24 . The net effect is to reduce the air resistance to club head motion, thereby facilitating an increased (enhanced) velocity for a greater ball travel distance. 
         [0021]      FIG. 5  shows, in phantom, a golf ball  36  in the path of the club head just prior to being stuck. Passages  30  are spaced apart by a distance that approximates the golf ball diameter. Face  14  of the club head has an optimal ball-strike point  18  ( FIG. 4 ) that is designated by the golf club designer as the ball strike point that will produce the greatest ball travel distance for a given input force. Strike point  18  is located half way between the two air passages  30 , such that when the ball is struck in the intended fashion the ball does not come into contact with either passage entrance opening. Each entrance opening is spaced from strike point  18  by a substantial distance that is approximately equal to the golf ball radius, such that the ball can contact face  14  above or below optimal strike point  18  without engaging either passage  30 . 
         [0022]    Each exit opening  33  is located in an area of curvilinear rear face  16  that communicates with wake area  24 , so that air exiting each passage immediately raises the pressure in wake area  24 , thereby reducing wake area turbulence and minimizing the suction effect on rear face  16 . 
         [0023]      FIGS. 6 through 8  show another form that the invention can take. In this case the air passage means comprises a series of separate circular cross-section air passages  30 A and  30 B, each spaced a substantial distance from optimal strike point  18 . Passages  30 A have entrance openings located near the upper edge of front face  14 . Passages  30 B have entrance openings located near the bottom edge of front face  14 . As shown, each passage has a circular cross section. However other cross sectional shapes could be used, e.g. oval. Preferably the cross section should be “corner free” in order to avoid flow losses associated with such corners. Each passage  30 A or  30 B extends from face  14  through the club body to rear face  16 , so that during a ball-striking motion air in the path of the club head is transferred from the pressurized zone  20  to the depressurized wake area  24 . The net effect is to reduce air resistance and increase club head velocity (as more particularly described in connection with  FIGS. 3 through 5 ). 
         [0024]    As best shown in  FIG. 8 , each air passage is defined by a sleeve  39  formed separately from the club head body. Each sleeve is formed of a high strength material (e.g. titanium) so as to reinforce the club head against structural failure, e.g. splintering or deformation. 
         [0025]    While specific forms of the invention are shown in the drawings, it will be appreciated that some variations and alternate designs can be used while still practicing the invention.