1 GB 2 141 035 A 1
SPECIFICATION Golf putters
This invention relates to golf clubs. More particularly, this invention relates to golf putters having a soft striking face of controlled properties which imparts to the golfer using the putter improved touch, feel, and control, and enhanced ball rebound response from the putter face.
It is recognized by a golfer that the game of golf has two fundamentally distinct aspects. One aspect is on the driving tee and fairway, and the other is on the putting green. On the driving tee and fairway the golfer looks to equipment which will maximize the distance of ball travel even at some sacrifice in ball control. Golf woods and irons, therefore, normally utilize a relatively heavy head set at the end of a relatively long shaft. These woods and irons are normally swung with the greatest power possible, consistent with position and conditions on the golf course, all to provide greater distance of ball travel. It has been suggested to incorporate into the head or face of a wood a plastic material having high resiliency and hardness to provide greater distances of ball travel.
On the putting green, the golfer is not primarily 90 concerned with power and distance, but needs to accurately propel the ball to and into the hole with as few strokes as possible. Accurate propulsion of the ball to and into the hole requires a sense of touch and feel by the golfer between the golf ball 95 on the green and his putter. The desire of the golfer to maximise the touch and feel necessary to accurately control the direction of the ball movement and the distance of the ball movement on the putting green has led to literally hundreds 100 of putter shapes and designs. The various shapes and designs have included putters having heads with an increased mass to increase the distance of ball travel with a short backswing, which increases accuracy; localization and balancing of the mass in 105 the head to improve directional accuracy; decreased mass in the putter head to provide increased accuracy, and the use of a striking face made of rubber or plastic material to impart a sense of feel and touch while controlling the rebound characteristics of the ball when struck with the rubber or plastic face of the putter. The various putter designs and various weights have received a mixed degree of success. However, up until now no putter having a rubber or plastic striking face has been successfully marketed and none are presently being marketed.
OBJECTS AND GENERAL DESCRIPTION OF
THIS INVENTION Accordingly, it is a primary object of this invention to provide a golf putter having a soft face formed from an elastomer chemically formulated to provide enhanced touch, feel, and ball control, as well as controlled rebound 125 characteristics.
Another object is to provide a golf putter designed for use with a stance wherein the natural body movement of the golfer is utilized in stroking or swinging the putter.
Heretofore when a golf putter utilizing a rubber or plastic face has been suggested, it was believed that the essential characteristics of the rubber or plastic was high hardness. It was believed that a soft material gave a slow rebound, and that increased hardness gave an increased rebound and increased speed as well as what was believed to be the necessary durability. Accordingly, hardness was the ultimate and only criteria used in the selection of the elastomer.
It has now been determined, that high hardness is not required and, in fact, can be detrimental to providing a striking force on a putter having the critical characteristics of touch, feel, and ball control. Rubber and plastic resilient faces having high hardness as described in the prior art were placed on putters having a metal head and contrary to expectation, the putters did not provide improved touch and feel. However, the rebound characteristics were substantially lowered relative to a putter with a metal striking face. Surprisingly, however, it has been discovered that an elastomer having high resiliency, i.e., a resiliency above about 45% rebound (Basnore) with a minimum hardness of about 70 Durometer A and preferably a hardness below the hardness of a golf ball which is in the range of, or above 99 Durometer A and 50 Durometer D at the surface of the ball, gave excellent touch and feel permitting accurate ball control. Additionally, such elastomers had rebound characteristics equal to or better than the rebound characteristics of a metal head.
It is believed that elastomers which have a hardness above about 70 Durometer A, but below the hardness of a golf ball, are still sufficiently soft so that the elastomer face and golf ball are compatible, which provides better touch and feel. Additionally, the coefficient of friction of elastomers having a hardness within the aforesaid range improves or contributes to the feel and touch.
It is further believed that an elastomer on a putter face having a hardness as above defined permits the golf ball when softly or gently stroked, as on a putting green, to penetrate into the elastomer face in contrast to the golf ball being compressed as is the case if the face of the putter has a hardness greater than the hardness of the ball. The high resiliency of the elastomer without shock-absorbing or dampening effect causes the ball, after penetrating into the elastomer, to rebound sharply without energy loss. The sharp rebound without energy loss increases the distance of ball travel. The increased distance of ball travel in turn permits the utilization,of a shorter backswing, substantially increasing the accuracy of the swing and, thus, direction of ball travel.
Accordingly, the present invention provides a golf putter having a soft elastomeric face, the elastomer having a hardness of at least 70 Durometer A and a hardness below the hardness 2 GB 2 141 035 A 2 of a golf ball. Additionally, the elastomer has a resiliency sufficient to cause a golf ball, after penetrating into the elastomeric face to rebound a distance equal to or greater than the distance that a golf ball will rebound when stroked with an equivalent force with a metal face of a putter. This putter, because of the soft face with its unique characteristics, provides excellent touch and feel, contributing to greater control of direction and distance of a stroked golf ball. However, elastomers having the hardness and resiliency as above defined are sufficiently tough to resist abrasion and tear.
A preferred putter provided by the present invention includes a head having a face with a width greater than its height, the base of the face having a contour, preferably a curvature, from one side of the face to the other. Additionally, the shaft is positioned in the head at an angle to a vertical line passing through the center of a horizontal line extending across the face of the putter. The top of the face of the putter is masked so that when the shaft is in a substantially vertical position the head has the appearance, when viewed form the top of the putter, of having a low point of the base of the face substantially in line with the shaft.
Accordingly, when the putter is positioned for putting by grasping the shaft of the putter at about mid-length or thereabouts with a single hand, the free end of the shaft extending up the forearm of the gripping hand, the golfer sees the head of the putter as though the lowermost point, or a lowermost point, on the face of the putter is substantially in line with the shaft, whether or not the lowermost point, or a lowermost point, is 100 directly below the shaft or is spaced to one side or the other. The golfer, therefore, is not detracted as to where the actual lowermost point of the face of the putter is, giving the golfer confidence in making a natural swinging or stroking arm movement substantially the same as in bowling.
Having described the invention in general terms, a specific and presently preferred embodiment will be described in detail in reference to the illustrative drawing wherein Figure 1 is a perspective view from the front of a preferred putter having a double wing club head and molded thereon an elastomeric face of controlled hardness and resiliency, intermediate portions of the shaft of the putter being broken away; Figure 2 is a perspective view from the front of another putter head wherein an elastomeric face of controlled hardness and resiliency is indented into a metal head; Figure 3 is a perspective view from the front of another putter comprising a metal head portion integrally molded with the putter shaft and an elastomer having controlled properties molded entirely around the metal head portion; Figure 4 is a cross-sectional view of the putter of Figure 3 taken along line 4-4 of Figure 3; Figure 5 is a perspective view from the front of a putter head similar to the putter illustrated in Figure 2, but wherein the face of the putter 130 comprises first and second elastomersl Figure 6 is a schematic view of a package containing a plurality of elastomeric pads for affixing to the striking face of a putter; 70 Figure 7 is a schematic perspective view showing the method of putting of this invention; and Figure 8 is a schematic perspective view illustrating a modification of the method of putting as shown in Figure 7.
Reference is first made to Figure 1 which illustrates a putter generally identified by the numeral 15 which includes a double wing head generally identified by the numeral 16 and a shaft 17 extending upwardly from head 16. Head 16 includes a platelike front portion 8 which includes a striking face 9 having a contoured base including a flat portion 7. Head 16 has a rearwardly extending body 10 to provide a substantially T- shaped putter. As shown, shaft 17 extends upwardly from the top of the rearwardly extending head portion 10 at an angle of at least 10 degrees in relation to the flat portion 7. The face 9 of the putter has molded thereto a resilient elastomer 6.
go The elastomer face as shown is approximately three-sixteenths (3/16") inch in thickness and completely covers face 9. The elastomer is fabricated from Adiprene 5418, a urethane elastomer manufactured and sold by the duPont Company. ADIPRENE 5418 is the reaction product of a polyether and diphenyl methane, 4,4' diisocyanate, the polymer terminated with free isocyanate groups which were subsequently cured with 1,4-butanol-diol. The elastomer has a hardness of 83 Durometer A and a resiliency of 70% (Bashore). The hardness and resiliency compares with a hardness of 90 Durometer D and a resiliency of 15% (Bashore) for a brass metal face putter.
The putter of FIGURE 1 having the elastomer face prevents a golf ball when stroked with the putter from skidding or slipping even when a backspin or twist is applied to the golf ball. This is in contradistinction to a metal face where slipping and skidding will occur. Additionally, the elastomer face permits a golf ball to penetrate into the elastomeric face when stroked with a golf putter due to its relatively low hardness in relation to the golf ball, with the ball rebounding sharply from the elastomer and rebounding a distance greater than the distance of rebound of a golf ball when struck with a metal face putter with equal force.
In contradistinction, an elastomeric face made from each of ADI PRENE L-1 00, a urethane polymer based on a polyether reacted with toluene diisocyanate and terminated with free isocyanate groups, and cured with MOCA (4,4methylene-bis-2-chloroa nil ine), and ADIPRENE L-31 5, a urethane polymer which is the reaction product of a polyether and toluene diisocyanate cured with MOCA failed to provide the desired feel and touch; and, additionally, has rebound characteristics inferior to the rebound characteristics of a metal face putter. The L-1 00 3 GB 2 141 035 A 3 polymer had a hardness of 90 Durometer A and a resiliency of approximately 50%, whereas ADIPRENE L-31 5 had a hardness of 99+ Durometer A, 73 Durometer D, and a resiliency of 5 approximately 50%.
The aforesaid examples establish the critical nature of the elastomer in providing a putter having the sense of feel and touch essential for good ball control as to direction and distance.
FIGURE 2 illustrates an embodiment of a putter 75 wherein the elastomeric face 6 is indented into a brass putter head 10. The putter, therefore, has a slightly raised soft elastomeric face 6.
FIGURES 3 and 4 illustrate a putter wherein all elastomer 6' surrounds a metal head portion 101 which is integrally connected to shaft 17. The putter of this design can be used by either a right or left-handed golfer.
FIGURE 5 illustrates a putter having an elastomer face section 6 and an elastomer face section 6'. Face section 6 providing a first point of contact is made from the elastomer ADIPRENE 5418 having a hardness of 83 Durometer A and a resiliency of 70%. This point of contact, as hereinbefore stated, provides a sharp rebound.
Face section 6' utilizes an elastomer having a lower rebound response, as for example elastomer ADIPRENE L-1 00. The golfer can stroke the ball with the putter of FIGURE 5 so that the ball will contact face section 6 under normal putting 95 conditions. However, if the golfer is putting downhill and desires less ball response, the toe of the putter having the face section with a lower response can be utilized to contact the ball. In this manner, the ball can be carefully controlled.
FIGURE 6 illustrates a package 20 containing four different elastomeric pads 22 having different degrees of hardness and resiliency, and different rebound characteristics. Each of the elastomer pads contained in package 20 has means on a second face thereof, such as a pressure-sensitive adhesive, which permits the bonding of the elastomer pad to the face of a putter. In this way the golfer can select the particular elastomeric face to suit his own desires, or he can change elastomer faces, if he desires. As apparent, therefore, the golfer can effectively tailor his own putter having a rebound response conforming to his particular golfing technique and desires.
As will be apparent to one skilled in the art, various polymers including polymers having different chemical formulations can be fabricated to meet the hardness and rebound characteristics essential to provide an elastomeric face in accordance with the present invention. The 120 essential characteristic, as hereinbefore stated, is that the elastomer be chemically formulated to produce the unique rebound response which permits penetration of the elastomer by a golf ball when stroked and a sharp rebound without 125 substantial energy loss. Urethane polymer ADIPRENE 5418 is illustrative of such elastomers.
Moreover, the thickness of the elastomeric face can vary. Although it has been found that a thickness of three-sixteenths (3/16") inch is 130 acceptable, the thickness can be increased or decreased with acceptable performance of the putter.
As used herein, -percent resiliency" is determined using the standard Bashore rebound method. "Hardness Durometer A and Durometer W are based on procedures ASTM D676-59T and ASTM D 1484- 59. The term "eiastomer" as employed herein is used in the broad sense to include materials polymeric in nature and which have the essential hardness and resilience properties herein defined. -Controlled dampening-, as used herein, means that the elastomer will permit penetration and will rebound without substantial energy loss.---Stroked",as it is used herein, is to define the gentle or soft contact of a golf ball with a putter on a putting green in contrast to the power swing utilized by the golfer on the driving tee or fairway.
FIGURES 7 and 8 illustrate a preferred method of using the putter illustrated in FIGURE 1 which utilizes free wrist movement. In the embodiment of FIGURE 7 the golfer will stand in a slightly crouched position with only a slight bending of the knees, slightly to one side of the ball 18. Preferably the ball will be slightly forward of the inside foot of the golfer. The shaft of the putter is gripped in hand 20 at a point remote from the free end of shaft 17, with the free end of the shaft extending upward with respect to the golfer's forearm and terminating at a point below the inner elbow of the gripping arm. Free arm and hand 24 of the golfer is extended across the golfer's body, with the hand engaging the shaft-gripping arm substantially at the wrist with thumb and forefingers. With this engagement the free end of shaft 17 is maintained in loose contact with the forearm and with the free arm, permitting free movement of the wrist of the gripping hand. When the putter is stroked to engage the ball, the free movement of the wrist of the gripping hand provides exceptional feel as the putter face contacts the ball. The free wrist movement permits good control of the force of contact between the ball and the face of the putter resulting in good accuracy in both direction and distance of bail travel.
In the modification of FIGURE 8, the putter is gripped substantially as described with reference to FIGURE 7. However, in this modification the free hand does not engage the gripping hand or arm, but rather loosely engages the free end of the club shaft, again permitting free movement of the wrist. The free wrist movement again permits control of the putter as the putter face contacts the golf ball, providing accuracy in direction and distance of ball travel. The engagement between the free end of the shaft and the free hand extending across the body provides improved guidance and stability to the putter in the course of stroking the putter.
The present invention includes, therefore, an improved method of putting, permitting increased putter control while utilizing natural body movement.
4 GB 2 141 035 A 4 The variations as above stated and others, being within the spirit and scope of the invention, 20 are to be covered by the appended claims.
The linear measurements of 3/1W used hereinbefore correspond with 4.5 mm.