The present invention generally relates to golf club construction and more particularly to an improved golf putter having a ball-striking head formed from a lead glass material that produces high energy transfer to the ball with reduced vibration of the head upon impact for greater feel and consistency in putting.
In the game of golf, there is perhaps no more important aspect than putting, the golfing stroke designed to cause a golf ball to roll on the surface of the green into or near the hole. Because of the significant effect that putting has on a golfer's score, much time and technology has been applied to improving the golfer's ability to propel the ball in the intended direction and over the entire distance to the hole using the golf club commonly called the putter. A significant focus of the technology applied to improve putting performance has been directed at the putter itself and particularly the construction of its ball-striking head affixed at the base end of an elongated shaft that is typically held with both hands of the golfer upon a grip at the opposite end of the shaft. Numerous putter heads have been designed and developed in a variety of shapes and constructions to enhance putting performance by increasing the “feel” that the golfer senses in his or her hands at the moment of impact between the golf ball and the putter head. The characteristic “feel” of the putter or tactile sensation transmitted from the striking face of the putter head along and through the shaft to the hands of the golfer on the grip is generally considered to be the most important factor in providing consistent and reliable distance control in putting. Somewhat like a feedback response at the moment of impact with the ball, the “feel” of the putter head together with its visual appearance are often the most commonly cited bases for improved putting control and accuracy.
In pursuit of optimal “feel” in the putting stroke, putter heads have been constructed of various materials and formed in a wide variety of configurations. Most common materials used in the fabrication of putter heads have included metals of aluminum, steel, brass and most recently titanium, and non-metals such as wood, ceramics, graphite, plastic and other elastomers. Composite materials have also been employed and joined together in putter construction to achieve desired physical characteristics of mass weight distribution, moment of inertia and resiliency, particularly with respect to the striking face of the putter head. Glass has been identified as an optimal putter material because of its appearance, formability and resiliency and while some putter head designs have been successfully developed in forms made in whole or in part from glass materials, they have not been found entirely satisfactory in providing a strong and durable putter with the degree of “feel” that is necessary to enhance putting performance. These prior art glass putter heads have been made predominately from soda-lime glass and/or borasilicate glass and are found to be relatively low in their characteristic mass and somewhat high in the elasticity of their striking surface to achieve optimal “feel” desired by golfers in effecting the putting stroke. Because of the generally positive physical characteristics otherwise exhibited by glass as a putter head material, it is therefore important to devise a new and unique putter head construction made from a glass material that affords significant improvement in performance and “feel” over the prior art putter head designs.
Accordingly, it is a general purpose and object of the present invention to provide a novel golf putter construction that improves the putting ability of a golfer.
A more particular object of the present invention is to provide an improved golf putter constructed having a novel ball-striking head capable of providing the golfer with an increased “feel” upon striking the ball that enhances the golfer's control of ball travel.
Another object of the present invention is to provide an improved putter head construction made of a glass material that imparts maximum energy transfer to the golf ball at impact with minimal vibration affecting the putter head to produce a greater “feel” response or tactile sensation in the hands of the golfer.
Still another object of the present invention is to provide an improved glass putter head that is attractive in its appearance and easily formed in a variety of configurations that can visually aid the golfer in striking the golf ball in the desired direction of travel.
A still further object of the present invention is to provide a glass putter head that is strong and durable through extended golfing use, economical to manufacture, and easily adapted to a variety of shaft connections.
Briefly, these and other objects of the present invention are accomplished by an improved golf putter constructed having a head made from a lead glass material containing at least 24% lead oxide in its formulation. The lead glass material formulation is heated to a full melting point of about 2500° F. and maintained at such temperature to remove impurities and bubbles before being reduced to a working temperature range of 1500°-2000° F. While in the working range, the lead glass material is press molded into the desired shape of the putter head or otherwise formed into billets that are milled or machined using conventional glass cutting techniques. Upon formation of the desired shape, the body of the putter head is annealed to remove stress in the lead glass material and thereafter the exterior of the putter head is treated to mechanically strengthen the surface area and prevent chipping of the putter head. The resulting lead glass putter head exhibits a density between about 3.0 to 5.0 grams/cm3 and a Young's modulus between about 50 to 70 GPa that cause the putter head to impart high energy transfer to the ball upon impact with minimal vibration of the head for greater feel of the impact and consistency in putting. The lead glass putter head may be formed into a variety of configurations each adapted to affix to a conventional putter shaft.
For a better understanding of these and other aspects of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which like reference numerals and character designate like parts throughout the figures thereof.
For a fuller understanding of the nature and objects of the present invention, references in the detailed description set forth below shall be made to the accompanying drawings in which:
The following is a detailed description of a preferred embodiment of the present invention and the best presently contemplated mode of its production and practice. This description is further made for the purpose of illustrating the general principles of the invention but should not be taken in a limiting sense, the scope of the invention being best determined by reference to appended claims.
Referring now to
Referring now to
A central cavity 20 having a generally cylindrical shape is formed to extend internally through the body 16 of putter head 14 in a direction substantially perpendicular to the top and bottom surface of the body. The central cavity 20 narrows slightly in its diameter from a maximum circular opening made at the surfaces on both the top and bottom of the body 16 and maintains a slightly reduced diameter through the middle thickness of the body. The surface openings of the central cavity 20 are slightly larger than the standard diameter of the golf ball while the reduced diameter of the cavity in the middle of the body 16 is slightly less than standard golf ball diameter. This configuration and sizing of the central cavity 20 thus permits the body 16 of putter head 14 to engage and hold the golf ball within the cavity upon insertion of the ball from either the top or bottom of the body and particularly allows the golfer to pick-up and retrieve a golf ball from the ground on or around the green surface after putting.
A small circular socket 22 typically drilled into the top surface of the body 16 of putter head 14 is sized and shaped to receive and fit closely the bottom end of shaft member 12 for securing attachment to the putter head. Socket 22 is located near to the heel of putter head 14, as shown in
It should be noted and understood that adjustment of the size, depth and angle of incline of the socket 22 may be made to accommodate any type of shaft member 12 and will be instrumental in establishing a proper position of the body 16 of putter head 14 relative to the shaft that permits placement of the putter head squarely behind the golf ball and substantially flat to the green surface when the putter 10 is held in address position by the golfer. It should be further understood that the location of the socket opening 22 may be adjusted upon the body 16 of putter head 14 to suit the particular configurations of the shaft member 12 and the physical requirements of the golfer, and particularly may be moved from the heel position shown on the embodiment of
Alternate configurations of the lead glass putter head construction according to the present invention are shown in
In
The main aspect of the present invention is the integral construction of the putter head, in those of the described forms or other selected configurations, from a lead glass material containing at least 24% lead oxide in its composition. Such a lead glass material, sometimes referred to as “lead crystal”, is most often used in making decorative glass objects due to its high refractive index that promotes sparkling and a relatively soft surface that facilitates its decoration by grinding, cutting or engraving. For just those characteristics that make lead glass ideal for decoration, as well as its further brittle character, lead glass has not heretofore been effectively used and processed in the construction of putter heads.
The lead glass material preferred for use in the present putter head construction is a formulation containing at least 24% lead oxide (PbO) or the equivalent amount of PbO combined with and another heavy-metal oxide, such as that of antimony or barium. A first working formulation of the lead glass material found effective in the present invention is as follows:
In its completed form, whether produced by press-molding or from a machined billet, the resultant putter head of the present invention undergoes an annealing cycle to remove the stresses created in the lead glass. This process of annealing requires the hot glass material to cool uniformly through the softened glass stage of the material, down to the solid state to allow the glass molecules to align in an orderly fashion. A typical annealing cycle for the lead glass putter head constructed according to the present invention includes the following steps in sequence: lowering the temperature of the putter head to an upper annealing level of 940 to 970° F., this step being permitted to occur rapidly in the case of the press-molded form; gradually reducing the temperature level at the controlled rate of 50° F. per hour to the designated annealing temperature of 900° F.; maintaining the designated annealing temperature of 900° F. for a period of one hour; reducing the temperature level, again at the controlled rate of 50° F., to the designated strain point temperature of 850° F.; and lowering the temperature of the putter head to an ambient level at a more rapid rate of 100 to 150° F. per hour.
After annealing is completed, the lead glass body of the putter head is further processed and submitted to one or more surface treatments intended to strengthen the surface areas of the body and its lead glass material so as to resist chipping of the putter head construction upon impact. Conventional surface treatment methods including fire polishing or thermal toughening and chemical toughening using a standard ion exchange procedure such as a salt bath of SiO2 or KNO3 at 420° F. may each be employed or combined to provide the putter head body with a mechanically strengthened lead glass surface with a depth of up to 100 microns.
The resulting putter head construction exhibits an excellent combination of physical characteristics, particularly a relatively high density and relative low Young's modulus (E), which together have been determined to contribute to the optimal performance of the present putter head in producing high energy transfer to the golf ball upon impact with reduced vibration of the head for greater feel and consistency in putting. Young's modulus, also referred to as elastic modulus, is an important material parameter that indicates the ratio of stress to strain of the material under an applied force and is thus measured in units of pressure called Pascals (Pa). The value of the Young's modulus serves as an indication of the elasticity or stiffness characteristic of a material. A higher Young's modulus indicates a more stiff material and a lower E value, more elasticity. For comparative analysis, metals, such as low alloy and stainless steels, have E values near 200 GPa, while glasses, such as soda-lime glass (E=69 GPa) and silica glass (E=94 GPa) have much lower Young modulus values. It should be noted that the vibration experienced by a material structure upon impact is directly proportional to its Young's modulus value, and further in this regard, a dampening of the vibration experienced by a putter head upon impact with a golf ball is an important factor in increasing the golfer's felt response to the putt.
In the resulting putter head made from the first working formulation of lead glass material described above, a density of 3.33 grams/cm3 was measured along with a Young's modulus determined to be 55 giga-Pascals (GPa). These characteristic features of relatively high density and low elastic modulus in the lead glass material of the present putter head construction combine to contribute to an improved striking performance and increased “feel” demonstrated with the present putter head and are deemed instrumental in increasing the felt response upon impact while producing effective energy transfer to the golf ball for improved putting control. It should be understood that the addition of a substantial amount of lead in the form of PbO to a soda lime or borosilicate glass is found to yield a higher density glass material with lower elastic modulus. It should be noted, however, that the resultant effect of these combined features in the lead glass material used in the present putter head construction to increase “feel” and ball-striking control in putting is substantial and unexpected in view of prior art and reported technology.
Additional formulations of the lead glass material examined for the present putter head construction contain increased levels of PbO in the range of 25 to 45% of the composition with minor amounts of barium, less than 2% of the material composition, further added. The resultant effects of these additional formulations were to further increase the density up to about 4.00 grams/cm3 and vary the Young's modulus between 50 and 70 GPa. Except for evidence of increased brittleness in the higher ranges of PbO, a condition relieved by the surface strengthening treatment described above, the additional formulations of the lead glass material indicate substantially the same resultant performance in the present putter head construction, producing high energy transfer to the ball with reduced vibration of the head upon impact for greater feel and consistency in putting.
Therefore, it is apparent that the described invention generally provides an improved golf putter construction that enhances the putting ability of a golfer by increasing the “feel” or immediate feedback experienced by the golfer at the moment of striking the golf ball. More particularly, the present invention provides an improved putter head construction made of a lead glass material that is capable of imparting maximum energy transfer to the golf ball at impact with minimal vibration affecting the striking surface of the putter head to cause a more immediate “feel” or tactile sensation to be experienced by the golfer that enhance his or her ability to control the ball travel when putting. The described putter head made of lead glass material is further attractive in its appearance and can be easily formed in a variety of configurations that can visually aid the golfer in striking the ball in the desired direction of travel. In addition, the present putter head of lead glass material is strong and durable through extended use, economical to manufacture and easily adapted to different shaft connections.
Obviously, other embodiments and modifications of the present invention will readily come to those or ordinary skill in the art having the benefit of the teachings presented in the foregoing description and drawings. Alternate embodiments of different shapes and sizes, as well as substitution of known materials or those materials which may be developed at a future time to perform the same function as the present described embodiment are therefore considered to be part of the present invention. For instance, dye coloring material may be added to the formulations of the lead glass material to provide color shades to the putter head while maintaining its transparent appearance. Accordingly, it is understood that this invention is not limited to the particular embodiment described, but rather is intended to cover modifications within the spirit and scope of the present invention as expressed in the appended claims.