Patent Publication Number: US-6217460-B1

Title: Putter having plastic insert

Description:
FIELD OF THE INVENTION 
     This invention relates to golf putters. More specifically, this invention relates to a method for modifying a golf putter to insert a plastic putting face. The invention also relates to a putter having such a face. The invention relates to a plastic insert per se for a golf putter. 
     BACKGROUND OF THE INVENTION 
     The patent art is replete with golf putters of various shapes and attributes. The large majority of putters have flat metal faces. Occasionally hard metal inserts have been built into the face to provide for longer wear and a durable smooth flat surface which meets the ball. 
     In our experience we have detected a tendency of the ball to skid or wobble as it leaves the smooth metal putter face. Both the skid and wobble exacerbate the errant tendency of the ball leaving the putter when it has not been struck true. As a result, metal-faced putters are more apt to stray from the proper line between putter and cup. 
     An object of the present invention is to produce a putter having a plastic insert which reduces skid and wobble. 
     It is a further object to provide a putter having improved “feel”, that is, a cushioned feel whether the golfer is using a balata ball or a surlyn-covered golf ball. By the same token, it is an object to prolong the contact between ball and putter face for more accurate control of the ball path. 
     SUMMARY OF THE INVENTION 
     The present invention is, of course, described in the claims. Briefly, however, the invention is a process for modifying the face of a putter including the steps of milling out a recess in the face, inserting into the rear surface of the recess a carrier strip coated on opposites with adhesive, and providing a plastic insert plate with the same dimensions as the recess. The rear face of the insert is formed with closely spaced parallel V-shaped grooves running in one direction and another group of closely spaced parallel V-shaped grooves running in an intersecting direction, the grooves defining a plurality of pyramids having flat tops. The invention may also be described as a putter having such an insert and as a plastic insert per se, described above. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further objects and features of the invention will be clear to those skilled in the art from a review of the following specification and drawings, all of which present a non-limiting form of the invention. In the drawings: 
     FIG. 1 is a perspective view of a putter embodying the invention; 
     FIG. 2 is an exploded enlarged perspective view of the parts of the club head; 
     FIG. 3 is an enlarged elevational view of an insert embodying the invention; 
     FIG. 4 is a sectional view taken on the line  4 — 4  of FIG. 3; 
     FIG. 5 is an enlarged fragmentary view of a portion of FIG. 4; and 
     FIG. 6 is a fragmentary sectional view showing the adhesive carrier and its temporary peel strips on the opposite sides thereof. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A putter embodying the invention is shown in FIG.  1  and generally designated  10 . It comprises a shaft  12  having a curved lower portion  14  joined to the head  16 . It should be understood that the invention is not limited to any particular shape of the putter head or its shaft, but instead is applicable to putter heads having various shapes. 
     As shown in FIG. 2, in the process of the invention, a central portion of the flat face of the putter is milled out to present a recess  18  having a rear surface  20  which is in a plane parallel to adjacent portions of the putter face. 
     Into the recess is pressed a carrier strip  22  which is covered on both sides by an adhesive. In the second step, the insert  24  is pressed onto the adhesive cover face of the carrier strip  22  to adhere the insert  24  onto the putter head. 
     The depth of the recess is preferably equal to the thickness of the adhesive carrier  22  and the insert  24  so that the forward face of the insert, after assembly, is flush with adjacent portions  16 A of the putter face. 
     More specifically, the carrier strip  22  (FIG. 6) comprises a polyester film which is available from Adchem under the product designation 256M double-coated polyester film. The adhesive  26  is preferably a high tack, moderate deadload acrylic adhesive film coating which, prior to use, is provided with a peel strip  28 . Such peel strips are removed prior to assembly (FIG.  2 ). 
     Referring now to the nature of the insert, it may be machined to the pattern shown, but preferably is molded. It comprises a plate having a thickness of 0.1″ to 0.125″ of an acetal plastic. As an example, the plastic may be Delrin, available in sheet form or as molding powder, from its manufacturer. The insert  24  may have a smooth side  30  and a grooved side  32 . As shown in FIG. 5, the grooves  34  may be right angle grooves, that is, V-shaped grooves having vertex of approximately 90°. One group  36  of these groups extend in a given direction, while another group  38  extends in a intersecting direction with the intersection preferably being at 90°. 
     There is thus formed on the grooved face  32  of the insert  24  a pattern of 4-sided pyramids  40  (FIG.  5 ). Each of these pyramids has sides  42  at 45° to the outer surface plane of the insert. The pyramids are formed with flattened tops  44 , the tops being all in a single plane, preferably parallel to the smooth plane  30  (FIG.  4 ). These flat square-shaped tops  44  are spaced by the grooves  36 ,  38  so that they provide resilience in each pyramidal shape. The square tops  44  are 0.030 inch on each side, and the spaces between adjacent tops are 0.050 inch. The spaced tops  44  present a cushioned ball-striking surface. This is because each top, unsupported laterally, is more yielding upon impact with the ball than they would be if the outer side  32  were smooth. 
     The result is that a putter embodying the invention gives longer contact between ball and putter face than the usual metal-faced putter in which the only resilient element is the ball cover itself. As a consequence, with the invention, using a regular surlyn ball gives the golfer the cushioned feel as if he were playing with a balata ball having a more resilient cover than a surlyn ball. Some golfers who prefer playing with balata balls have actually asked that the thickness of the insert be reduced to lessen the cushion effect. At present, the inserts are made of a Delrin plate of 0.105″ thickness for balata ball users and 0.125″ for surlyn ball users. The effects are virtually similar, that is, a cushioned feel at impact of the club on the ball. 
     As stated, using the putter head with the insert described reduces both the skid and wobble customary with metal-faced putters and provides improved feel and control with either a balata- or surlyn-covered golf ball. 
     Variations in the invention are possible. Thus, while the invention has been shown in only one embodiment, it is not so limited but is of a scope defined by the following claim language which may be broadened by an extension of the right to exclude others from making, using or selling the invention as is appropriate under the doctrine of equivalents.