Patent Publication Number: US-4147349-A

Title: Set of golf clubs

Description:
This application is a continuation of co-pending application Ser. No. 646,866 filed Jan. 5, 1976 now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a set of golf clubs and more particularly to such clubs known as irons. 
     BACKGROUND 
     As all the mechanics involved in golfing have not yet been fully analyzed scientifically, it is not surprising that a relatively large number of theories have already been proposed in support of a large number of different shapes of club heads. 
     It is now an accepted fact that the speed at which a club head hits the ball and the relative position of the club head and ball at the moment of impact are the most important factors as far as length and accuracy of a drive. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a set of clubs of given weight, allowing any individual golfer to improve the length and accuracy of his drives. 
     This is achieved in so shaping the club heads of the set that the center of gravity of each head lies at a distance from the ground line of no more than 17 mm, while the ratio of the maximum height to the maximum width of each head is no more than 2.5. 
     The height of 17 mm corresponds to the normal impact point of a ball with a number 1 iron with the lowest loft known, that is to say with the highest impact point. It follows that the impact points of other heads in the set will always be below this 17 mm level. By so designing the heads that the center of gravity thereof also lays below the aforesaid level, the distance between the center of gravity and the impact point on the ball will be minimal throughout the set. 
     This low position of the center of gravity also increases the length of the lever system constituted by the golfer and the club, so that the striking power of the head is increased. 
     The chosen limit of height/width ratio provides for a relatively small frontal area of the head. This reduces air drag of the club head and thus provides for faster swinging speeds as compared to known heads. Furthermore, the relatively small frontal surface indirectly increases the probability of the golfer hitting the ball with the &#34;soft spot&#34; of the head. 
     According to one feature of the invention, the height of said frontal area is a constant throughout the set, which together with the location of the center of gravity, facilitates &#34;matching&#34; of the clubs in the set. 
     In each head, the face is upwardly connected to the back of the head by a surface sloping upwards from front to rear at an angle of not less than 90° plus the loft angle. This provision allows the golfer to visualize the orientation of the face of the head. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will now be described in more detail with reference to the appended drawings showing one preferred embodiment of the invention and wherein: 
     FIG. 1 is an end view of a club head according to the invention; 
     FIG. 2 is a view according to arrow P2 of FIG. 1; and 
     Figs. 3-10 are end views of the various heads forming a set. 
    
    
     DETAILED DESCRIPTION 
     As shown in the drawings, a head according to the invention comprises a head proper 1 and a shank 2. 
     The center of gravity CG of the head is located at a distance from the ground line GL of not more than 17 mm. 
     The ratio of the maximum height H of the face 3, measured in the plane of that face, to the maximum width W of the head, measured perpendicularly to the aforesaid plane, is no more than 2.5 and, preferably, less than 2. 
     This leads to a relatively small frontal surface of the head, as compared to known club heads. 
     The face 3 is connected to the back 4 by a surface 5 which slopes upwards towards the rear of the head at an angle of not less than 90° plus the loft angle of the considered head. By this provision, face 3 and back 4 are visually separated so that the golfer may easily correctly orient face 3. 
     A set of heads according to the invention is shown in FIGS. 3-10. These heads may differ from one another in loft and lie angles, as well as in weight, as known per se. 
     As illustrated, the height A of the frontal areas of the heads in the set is a constant, while the center of gravity of each head is below the CG limit line, lying at 17 mm from the ground line GL. 
     The sole 6 of each head is preferably curved, both lengthwise and crosswise of the head, with the lower edge 7 of face 3 located at least at 2 mm from the ground line GL. This reduces the penetration of the head into the ground when hitting an unteeed ball and also the penetration of the head into the ball when the latter is struck too high. As illustrated the sole 6 and back surface 4 are of different curvature for the club with least loft in FIG. 3 and the intersection of the curved surfaces is distinct whereas in FIG. 10 the sole 6 and back surface 4 blend smoothly, the other heads of the set having shapes of the sole and back surface varying therebetween. As further evident from the drawings, the ratio of the maximum height to maximum width is greatest for the head in FIG. 3 and least for the head in FIG. 10 and varies therebetween. 
     It will be understood that other embodiments of the invention may be contemplated, within the scope of the appended claims.