Golf putting practice device

A portable golf putting training device used by golfers to improve their putting stroke comprising a flexible plastic sheet with a reflective layer and guide lines both parallel to and perpendicular to the intended path of the ball. The guide lines and the reflective surface provide feedback to the golfer during the stroke as to whether (a) the club face is square to the intended path; (b) the putter has been drawn back parallel to the intended path; (c) the backswing is slow and smooth; and (d) a long follow-through has been made. Preferably the device is made of a clear acrylic material with a protected reflective layer in which the guide lines are cut. The sheet is oblong and provided with an end-to-end longitudinally oriented target line that bisects the sheet. A spot for mounting a golf ball is marked less than half-way along the target line as measured from the backswing end. The spacing between successive transverse guide lines increases as one progresses from the backswing end to the ball mounting spot. Thereafter from the ball mounting spot to the follow-through end, the transverse guide lines are uniformly spaced.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a plan view of the preferred embodiment of a putting trainer. Viewed from above, a putting trainer 1 is a reflective multilayered sheet, generally of rectangular shape with a long axis 2 and a short axis 3 , with guide lines thereon as described below. The sheet 1 comprises an upper transparent layer 11 of relatively hard but flexible plexiglass or transparent plastics material, a reflective coating 12 on its underside, and a protective bottom layer 13 , as will be described in more detail below with reference to FIG. 2 . The long axis 2 of the sheet 1 is aligned parallel to the desired path of the ball. The sheet 1 should be long enough to accommodate a full backswing and follow-through of an average golfer; the golfer is able to use the edge between the face and the sole of the club to keep the club face aligned parallel to the guide lines 7 (to be described below) throughout the complete backswing, putting stroke, and follow-through. In an exemplary embodiment, the putting trainer 1 is approximately 1 m (39″) long which is sufficient to allow golfers to practice a wide range of lengths of putt with a full backswing and follow-through. The short axis 3 is aligned generally parallel to the golfer's feet which are shown schematically in dashed lines as 4 (left foot) and 5 (right foot), for a right-handed golfer. The width of the putting trainer 1 should be small enough so that, in a comfortable stance, the golfer's toes do not overlap the putting trainer 1 . In an exemplary embodiment, the putting trainer 1 is approximately 18 cm (7″) wide. A right-handed golfer stands as schematically shown by the footprints 4 and 5 in FIG. 1 with the backswing end 9 on his right and the follow-through end 10 on his left. Optionally, the corners of the sheet 1 may be slightly rounded to avoid chipping or injury during handling. The putting trainer presents a flat, generally mirrored surface on which a number of guide lines to be described below and a mounting spot 8 are visible. The putting trainer has: (1) one guide line 6 running parallel to the long axis for the length of the sheet 1 and bisecting the sheet 1 longitudinally (the “target line”); and (2) a plurality of transverse guide lines 7 (the “cross lines”, only three of which are labelled in FIG. 1 ) running parallel to the short axis and perpendicular to the target line, each extending across the entire width of the sheet 1 , the guide lines 7 being spaced along the length of the sheet 1 in the manner further described below. The mounting point 8 is marked as a distinctive point where the golfer places the ball (not shown) on the putting trainer 1 . The mounting spot 8 should be as small as possible so as not to distract the golfer during the swing but yet be large enough and of sufficient contrast to the background to be seen easily by a standing golfer. The mounting spot 8 may suitably be shaped and coloured in a variety of ways. In an exemplary embodiment, the mounting spot 8 is a yellow circle of approximately 0.25 cm (0.1″) diameter. It may be formed on the underside of the sheet 1 by placing a drop of coloured paint at the intersection of the target line and a selected cross line. In the preferred embodiment, the putting trainer is not symmetric along the long axis about the mounting spot. FIG. 1 shows a backswing end 9 and a follow-through end 10 . The length from the mounting spot to the follow-through end 10 is greater than the length from the mounting spot to the backswing end 9 . A left-handed golfer, whose footprints are not shown, stands on the other side of the putter trainer 1 with the backswing end 9 on his left and the follow-through end 10 on his right. FIG. 2 shows a front elevation of the putting trainer 1 and an enlargement of one area of finer detail. The rear elevation is identical, save for the orientation of the distribution pattern of the ends of the cross lines 7 , whose spacing invariably increases from the backswing end 9 to the mounting spot 8 and thereafter is uniform from the mounting spot 8 through to the follow-through end 10 . The putting trainer 1 is made as a sheet of a transparent flexible material 11 with a reflective layer 12 protected by a durable plastic coating 13 , which is widely available commercially. An acrylic mirror product made by Plaskolite Inc. of Columbus, Ohio is suitable for the purpose. The putting trainer 1 has a flat upper surface and is of a generally uniform thickness. A golf ball can roll on the smooth surface to the follow-through end 10 where it drops to the surface underlying the putter trainer. As long as the drop is small, experience with the putting trainer shows that the effect of the drop on the path of the golf ball is negligible. However, optionally, the putting trainer may be bevelled at the follow-through end 10 to reduce the abruptness of the drop from the upper surface to the surface underlying the putter trainer. The thickness of the material is selected to balance the preference for a thinner product which gives a smaller drop at the follow-through end and a greater flexibility (and thus is better able to conform to the underlying surface) against the preference for a thicker product which is stronger. For the acrylic mirror product made by Plaskolite Inc., a thickness of 3 mm (&frac18;″) is suitable. The reflective layer 12 is of a conventional composition and has a mirrored surface reflecting upwardly which is adhered to the bottom surface of the putting trainer by conventional means and which is protected by a durable plastic coating 13 . In the preferred embodiment, the target line 6 and the cross lines 7 shown in FIG. 1 are formed by making channels 14 through the plastic coating 13 , the reflective layer 12 and a portion of the transparent sheet 11 with a saw blade or a knife, by etching, chemical solvents or by other conventional means, so that sufficient material is removed from the plastic coating 13 and the reflective material 12 to make the channels distinctly visible from above. The width of the channels 14 is not critical but should be sufficient so that the target line 6 and cross lines 7 are easily visible to a golfer whose head is as much as 2 m (6′)above the upper surface of the putting trainer 1 . In an exemplary embodiment, a channel width of 2 mm ({fraction (1/12)}″) is found to be suitable. FIG. 2 shows an enlargement of the front view of one cross line 7 formed as a channel 14 in the reflective layer 12 and plastic coating 13 . Optionally, the areas of the reflective layer 12 from which reflective material have been removed may be painted or coated to improve their visibility. In the preferred embodiment, the sheet 1 is first manufactured with three layers and channels 14 are cut as described above. However, other suitable manufacturing methods may be followed. For example, the target line 6 and the cross lines 7 may be: (1) applied with adhesive as distinctive strips of contrasting material to the lower layer of the transparent sheet 11 prior to the application of the reflective layer 12 and the plastic coating 13 ; or (2) applied with opaque paint to the lower layer of the transparent sheet 11 prior to the application of the reflective layer 12 and the plastic coating 13 . Alternatively, the reflective layer 12 may first be adhered to the lower surface of the transparent sheet 11 and the target line 6 and the cross lines 7 formed, prior to the application of the plastic coating 13 , by ablating portions of the reflective material 12 and applying opaque paint to form a suitably visible pattern of lines. FIG. 3 is an elevation view of the backswing end 9 and an enlargement of the area in the vicinity of the target line 6 . The elevation from the follow-through end 10 is identical. This elevation shows the transparent acrylic material 11 with affixed reflective layer 12 , protective plastic coating 13 and a channel 14 cut to make the target line 6 . FIG. 4 is a bottom view of the putting trainer 1 . This bottom surface of the putting trainer has a plastic coating 13 which protects the reflective material (not shown) and in which are cut the channels that make the target line 6 and the cross lines 7 . In the preferred embodiment, the mounting spot 8 is made by painting a small, approximately circular area at the intersection of the target line and the line of address. FIG. 5 shows a sketch of a right-handed golfer 15 in the position he would assume at the end of the follow-through of his putting stroke using the putting trainer 1 . The location of the mounting spot 8 and the cross lines 7 is determined as follows: (1) A selection is made for the location of the mounting spot 8 along the length of the target line 6 . This preferably is in the region between one half and three quarters of the length of the putting trainer as measured from the follow-through end 10 . In the preferred embodiment, the mounting spot 8 is located at a point approximately 60-70% of the way along the target line 6 as measured from the follow-through end 10 . While the preferred location of the mounting spot 8 is within the designer's discretion, the design decision to provide in the preferred embodiment more trainer length for observing the golfer's follow-through relative to the backswing reflects the importance of the follow-through part of the swing. (2) Once the location of the mounting spot 8 is chosen, the cross line 16 is made through the centre of the mounting spot 8 (the “line of address”); (3) A set of evenly spaced cross lines 7 are made between the mounting spot 8 and the follow-through end 10 so that they are between about two and twenty in number. In an exemplary 1 m-length embodiment, there are five such cross lines 7 which, together with the line of address 16 and the follow-through end 10 , mark out six discrete reflective regions of equal size each of which is divided centrally into two parts by the target line 6 ; (4) One cross line 7 is made towards the backswing end 9 and separated from the line of address 16 by the same width as that used to space out the cross lines 7 made on the side of the mounting spot 8 towards the follow-through end 10 . (5) Additional cross lines 7 are added between the line described in the previous paragraph and the backswing end 9 of the putting trainer 1 so that each line is spaced from its predecessor by a successively narrower gap. In one embodiment of the invention, the spacing of the additional cross lines 7 is made so that the ratio of the distance from that cross line to its successor (or the edge at the backswing end 9 for the last cross line) is a fixed ratio, less than 1 and greater than zero, of the distance from that cross line to its predecessor. In the preferred embodiment of the invention, this ratio is selected to be between 0.7 and 0.9. In an alternative embodiment of the invention, the values for the ratio are drawn from a table, such values based on feedback provided by golfers as to their subjective experiences. One or more tables can be prepared from guidance provided by skilled golfers and used as models for preparing the guide line spacing. Ultimately, an empirical approach is best taken to guide line spacing selection and to dimensional choices generally. The putting trainer 1 is designed to produce a simple putting stroke that produces few errors and provides the assurance of a consistent and repeatable stroke. Ideally the stroke has a slow and smooth backswing without any jerking, a smooth forward motion, a square impact so that the desired path of the golf ball is orthogonal to the club face and a long follow-through with the putter continuing in contact with the ball so as to impart top spin which assists in keeping the ball on track. A golfer using the putting trainer employs the following steps to improve his or her putting stroke: (1) The golfer places the putting trainer 1 on the ground or on a surface indoors so that the target line 6 points along the path on which the golfer intends to hit the ball. (2) The golfer addresses the ball: (a) the golfer places the tips of his or her shoes equidistant from the edge of the putting trainer; (b) as measured by an imaginary line through his or her shoulders, the golfer stands parallel to the target line; (c) preferably, the golfer stands with his or her dominant eye exactly over the ball, the dominant eye being determined as follows: (i) the golfer stands over the putting trainer so that the mounting spot appears in the golfer's reflection equally between the eyes; (ii) the golfer, in turn and one at a time, closes each eye and observes the lateral shift of the image of the mounting spot; (iii) the dominant eye is selected as the open eye which produces the smallest lateral shift. (d) should the golfer choose not to determine his or her dominant eye, the golfer should stand with the mounting spot appearing in the golfer's reflection equally between the eyes. (d) the golfer places the club face just behind the ball with the putter's sweetspot marker on the target line 6 and directly behind the centre of the ball. (3) The golfer makes the club face vertical by tilting the club along the target line 6 until the club face cannot be seen either directly or as a reflection in the putting trainer 1 . (4) The golfer makes the club face parallel to the line of address 16 by rotating the putter handle until the bottom edge of the club face is parallel with the line of address 16 . (5) The golfer focuses on the ball resting at the mounting point 8 and does not move his or her eyes from that point throughout the stroke. (6) The golfer makes a slow backswing keeping the sweet spot marker directly above the target line 6 and the putter face perpendicular to the target line 6 throughout the backswing by checking the reflection of the putter face against the cross lines 7 . As the putter is drawn back, the cross lines 7 on the backswing side appear underneath the club face and are visible in the golfer's peripheral vision. If the putter is slowed smoothly the lines appear at a uniform rate. If the backswing is not slowed smoothly or is abbreviated then the cross lines do not appear at a uniform rate. This provides a clear visual signal to a golfer whether his putting stroke is as recommended. (7) When the farthest point of the backswing is reached, the forward swing and follow-through are commenced. Throughout the forward swing and follow-through, the golfer keeps the putter's sweet spot marker directly above the target line 6 and the putter's face should remain square to the target line 6 , this being confirmed by the reflection of the leading edge of the putter face being maintained parallel to the cross lines on both the forward swing and the follow-through. (8) At the end of the follow-through, the golfer holds his or her position for a few moments to get the “feel” of the position. (9) The golfer repeats this practice stroke slowly several times to imprint in muscle memory the pressures in the hands, wrists, arms and shoulders required to keep the putter's sweet spot and face on the target line 6 and square to the target line 6 throughout the putting stroke. (10) Once a golfer has the feel of this putting stroke, the speed of the stroke can be varied for putts of various lengths. The scope of the invention is not limited to the specific embodiments illustrated and described herein but is governed by the appended claims.