Aids for improving a player's golf stroke are well known. One type of aid shown in U.S. Pat. No. 4,720,109 by the present inventor includes a pair of relatively unobtrusive, thin, visible line segments which together form at least portions of opposite arms of a V-shape, and which is attached to a golf club with at least portions of the line segments extending forwardly of the plane of the ball-striking surface at a height above the bottom surface of the club head that is greater than the diameter of a golf ball to allow striking of the golf ball by the striking surface. The intersection of the line segments is located in a plane that is normal to the ball-striking surface of the head at the sweet-spot. Such an arrangement is particularly well adapted to assist the player in striking the ball at the sweet-spot.
In U.S. Pat. No. 4,167,268, guide means shown in FIG. 12 include substantially horizontally extending arms 51 and 52 between which the head of the golf club is viewed. The arms extend parallel with the putting face of the club, and when the club is not stroked on a straight line, they visually describe dis-similar spacing on the line of sight from the eye of the golfer advising the golfer that his stroke is not along a straight line path. Other types of aids include an arrow-type pointer for use in pointing the club head in the direction of the hole. Typical aids of this type are shown in U.S. Pat. Nos. 3,033,574; 3,198,525; 3,298,693; 3,292,928; 3,529,830; 3,667,761; 4,053,160; Des. 111,855; Des. 150,497; and Des. 188,677. In other arrangements the arrow-type pointer is included in a structure which includes an opening through which the golf ball is viewed when the club engages the ball. U.S. Pat. Nos. 2,670,209 and 4,002,343 show aids of this type.
Sighting devices which attach to the club shaft a spaced distance from the club head are shown in U.S. Pat. Nos. 2,898,109 and 3,951,415. Devices which attach lo the club face are shown in U.S. Pat. Nos. 3,489,415; 4,025,078; 4,130,282 and 4,323,246. Many prior art guides do not readily provide cognitive information relative both to the exact lateral location of the sweet-spot on the striking surface of the club head, and the club orientation, prior to, at the moment of, and following impact of the head of the club with the ball.