US 2880002 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
March 31', 1959 s. A. WETTY GOLF CLUB HEAD Filed July 19. 1955 INVENTOK STEPHEN A- WETTY A flora/v5 Y5.
United States PatentO GOLF CLUB HEAD Stephen A. Wetty, Royersford, Pa., asslgnor to S. A. Wetty & Sons, Royersford, Pa., a partnership Application July 19, 1955, Serial No. 522,896 Claims. (Cl. 273-169) This invention relates to a golf club and, more particularly, to a golf club head.
In the past, the so called woods; that is to say, the driver, brassie and spoon, have as a rule been made of wood, sometimes of a solid piece of wood with or without an insert and sometimes of wood laminae stacked one upon another. Where the club head has been of a solid piece of wood, it has of course been integral except as modified by the presence of an insert; on the other hand, where the club head has been laminated from a number of layers of wood stacked one upon another, the club head cannot properly be said to be integral, this in view of the presence of discrete layers of glue or some other bonding medium between adjacent laminae. A club head that is non-integral in the latter sense is subject to the possibility of ply separation, particularly if subjected to abuse, as, for example, by prolonged submersion in water.
It is an object of the present invention to provide a built-up club head in which the laminae are inseparably associated with each other in such manner that the club head, despite its laminar structure, is virtually integral. A further object of the invention is to provide a golf club head formed of laminae of synthetic resin, particularly a thermoplastic resin lending itself to mutual fusion of adjacent laminae to consolidate them into a unitary structure in which there is no possibility of ply separation. Still a further object of the invention is to provide a club head of this kind lending itself to personalization, as by distinctive coloring incorporated in the club head in such manner that it cannot be reached or removed without destroying the club head itself.
Another object of the invention is to provide a laminated club head in which, for weighting purposes, certain of the laminae are of a non-corroding metal, as, for example, aluminum, copper or stainless steel. In order to make it possible to avoid the use of cements and similar bonding media forming discrete layers, such metal laminae are provided with recesses which can receive the material of adjacent laminae of synthetic resin. If the synthetic resin is fusible, as is the case with the thermoplastic resins, an assembly consisting of synthetic resin laminae and metal laminae may be subjected to conditions' conducive to fusion of the synthetic resin, enabling it to flow into the recesses in the metal laminae. In this way is provided a unitary structure in which ply separation is virtually impossible.
Still another object of the invention has to do with the development of maximum impact resistance in the impact face of the club head. It is desirable that the impact resistance be as high as possible on that face of the club head which comes into contact with the golf ball, this in order to minimize the danger of scarring, denting, chipping or otherwise damaging the face of the club head. By using laminae that can be so related to each other as to develop maximum impact resistance along those edges thereof which form the face coming into contact with the golf ball, the present invention provides a club head that comesrnuch closer to being im- 'ice 2 mune from these dangers than do the club heads of the prior art.
Other objects and advantages of the invention will be apparent from the description which follows and from the accompanying drawings, in which:
Figure 1 is a full-size side elevation of a club head, attaching sleeve and shaft end, part of the attaching sleeve being shown in section;
Figure 2 is a front elevation showing the club head, attaching sleeve and shaft end on the same scale as in Figure 1; 1
Figure 3 is an exploded view showing-the attaching sleeve and shaft end in greater detail than in Figures 1 and 2; 1 g Figure 4 is a top plan of the club head of the invention illustrating some of the possibilities for personaliza tion, the scale being reduced below full size;
- Figures 5 and 6 are side elevations, likewise on a reduced scale, showing two variants of the invention in each of which the laminations in the club head run at an angle to the horizontal;
Figure 7 is a side elevation of a club head otherwise similar to that of Figure 5 in which metal laminae are used for weighting purposes; and
Figure 8 is a detail showing the manner in which the laminae are combined in the club head of Figure 7.
Figures 1 and 2 show a full size club head constructed in accordance with the teachings of the invention. The club head, generally designated 10, has a forward or toe end portion 11, a rearward or heel end portion 12, a'
sole surface 13 extending longitudinally between them,
and, defining a dihedral angle with the sole surface, a longitudinally extending impact face 14. The latter, the face of the club head in ordinary parlance, is difierently angled in different clubs, such angularity being in-' tended to give maximum loft, minimum loft or any intermediate loft, as may be desired.
In the club head of Figures 1 and 2, the club head it self is a composite of a large number of laminae 15, each so shaped, either initially or as a result of the finishing operation that is performed on the club head, as to give the latter the desired contour. As will be apparent from Figures 1 and 2, there is ordinarilylittle or no prospect that any two laminae, even though closely adjacent, will be shaped exactly alike. According to the invention,
they do, however, have in common the fact that they are so disposed in relation to each other as to develop maximum impact resistance over the area represented by impact face 14. From a practical standpoint, the fact that elsewhere over some of the surfaces of the club head, as, for example, in toe end portion 11 or in heel end portion 12, the impact resistance maybe somewhat less than that of impact face 14, is not a disadvantage.
To arrive at a condition of this sort in which maximum impact resistance values can be developed over impact face 14, it is desirable in making up laminae 15 to use blanks of a thermoplastic resin which has been extruded in sheet form. objects made by casting, compression molding, injection molding, transfer molding and like processes tend to develop the same or similar physical properties over all exposed surfaces. On the other hand, thermoplastic resin objects formed by extrusion processes usually have a microscopic grain structure that is characterized by orientation in the direction of extrusion. Such orientation of the grain influences the physical properties of the product.
Broadly speaking, it is common knowledge that ina solid rod made by extruding a thermoplastic resin such as cellulose acetate butyrate, cellulose acetate, cellulose nitrate or some similar thermoplastic resin, not necessarily cellulosic in nature, sections of therod taken at right angles to its longitudinal axis usually exhibit higher im- It is well known in the plastic arts that pact resistance values than the cylindrical surfaces that lie between the ends of the rod. It is not so well known that like conditions obtain in an extruded sheet of thermoplastic resin in that the leading and trailing edges of the sheet yield relatively high impact resistance values while the side edges and upper and lower surfaces show values which are generally considerably lower. In the two cases the results obtained are comparable. They are explainable by the orientation of the grain, which can be demonstrated by microscopic examination to be present in the product.
In the practice of the present invention, laminae 15 are formed from blanks taken from extruded sheets of cellulose acetate butyrate or the like in which there is such an orientation of the grain. In adjacent blanks, assembled to form laminae, the direction of orientation should preferably be the same; if so, like impact resistance values can be expected to be obtained in like edges of the various laminae. The laminae when assembled should be so related to each other that in each lamina the direction of orientation is in the direction indicated by the arrows in Figure 2; that is to say, the direction of the orientation should be toward the impact face of the club head. If this is done, the values obtained from impact resistance determinations made over the surface of impact face 14 will be found to average higher than those obtained by making such determinations in the vicinity of toe end portion 11 or heel end portion 12.
In building up club head 10, blanks taken from one or more extruded sheets of a suitable thermoplastic resin are first stacked one on another in a manner that will be apparent from Figures 1 and 2. They are not cemented together by means of intervening layers of conventional cements, as in the case of wood laminae, but instead are fused together in such manner that each blank in effect loses its own separate identity and becomes part of a cmposite that includes the blanks above and below it. To this end, the blanks are coated on adjoining top and bottom faces with a solvent that will cause softening of the resin and, when the softened blanks are brought into contact with each other, will bring about fusion of the material of one with the material of another.
Solvents appropriate for use with cellulose acetate butyrate, cellulose acetate, cellulose nitrate, etc. may be such common volatile solvents as acetone, methyl ethyl ketone and the various Cellosolves.
In certain instances, it may be desirable to carry out these operations at somewhat elevated temperatures, preferably short of temperatures high enough to render the material freely workable (usually about 200 degrees F.) and in any event not high enough to cause disappearance of the grain structure (usually about 400 degrees F.). In ordinary cases, however, the step of fusing together adjacent blanks can be accomplished at room temperatures. In either event, the step of consolidating the blanks is accomplished by, applying pressure to the stack after first coating adjacent surfaces of adjacent blanks with a suitable solvent.
After a short time, the solvent evaporates into the atmosphere, leaving a rigid composite in which the fusion zones are scarcely if at all discernible. If the blanks do not conform to the ultimate shape of the laminae as they are to appear in the club head, the club head may then be machined, hand-shaped by suitable tools, or otherwise finished to give it the desired contours. The product is a club head that is virtually integral, eventhough obtained by stacking like blanks together and consolidating them under pressure. From a practical standpoint, there is no likelihood of ply separation such as is found where laminae .of wood are cemented together in the ways known to'the prior art.
Either before or after the step ofcontour-finishing the club head, a bore 16'is formed therein, such bore conforming. to the angle to the horizontal which the club shaft itself is to take. However, bore 16 isconsiderably' wider than the diameter of the shaft, this so that it can receive an adapting sleeve 17 of a thermoplastic resin of the kind used in the blanks that go to make up laminae 15. As is clear from Figure 3, sleeve 17 consists of a narrow lower part 18 shaped like a hollow cylinder and a wider upper part 19 of frusto-conical shape.
Between the upper and lower parts of sleeve 17 is a shoulder 20 intended to abut the usual neck portion at the top of the club head. As indicated in Figure 1, shoulder 20 preferably is of approximately the same diameter as the outer diameter of the neck portion of the club head. From this zone it tapers gradually toward its upper end, approaching but not equalling the actual diameter of the club shaft. However, opening 21 in sleeve 17 is of uniform diameter from one end of the sleeve to the other.
In fixing sleeve 17 in place in the club head, the outer surface of cylindrical part 18 and the inner surface of bore 16 are first coated with a mutual solvent of a kind which is capable of causing the material of laminae 15 and the material of sleeve 1'7 to fuse together to form an inseparable bond. The lower cylindrical portion 18 of sleeve 17 is then inserted in bore 18, after which the whole is allowed to stand until the material or materials in the zone of fusion have hardened. In general, these steps should not be undertaken until after club shaft 22 has been inserted in and firmly bonded to the material of sleeve 17.
That portion of the shaft that is to be concealed by sleeve 17 is first roughened as at 23 (Figure 3), such roughening being for the purpose of causing the material of the shaft to grip and be gripped by the material of the sleeve. Such roughening need not take the form of knurling, as shown, but may take the form of a multiplicity of serrations or of a single helical groove extending from lower end 24 of the shaft to a point just short of that part of the shaft which is to project out of the sleeve. Sleeve 17 is then softened under heat until it becomes workable, usually at a temperature between about 200 and 325 degrees F.: at this stage, while the sleeve is still susceptible to deformation under pressure, the roughened end of the shaft is introduced into opening 21 in the sleeve. Thereafter, a suitably shaped tool is closed around cylindrical portion 18 and frusto-conical portion 19 of the sleeve, thus forcing the material of the sleeve into intimate contact with the roughened area on the shaft.
As an alternative method, the surfaces of opening 21 may be coated with a cement containing a solvent for the material of which the sleeve is formed, such solvent being employed for softening the resin and encouraging it to fllpw into the interstices in the roughtened area of the s aft.
After sleeve 17 has been firmly bonded to the knurled surface 23 on club shaft 22, the next step is that of inserting the sleeve in the bore in the club head. This is done as already described, using a mutual solvent to cause the two parts to soften and fuse together. The solvent action continues for a short while after cylindrical part 18 of the sleeve is inserted in bore 16 of the club head, but ultimately the solvent evaporates to the atmosphere. As it evaporates, the contiguous portions of club head 10 and sleeve 17 fuse together to form a firm, strong, inseparable joint the nature of which is such that the parts are virtually integral.
A club head made as described lends itself to personaliza'tion as indicated, for example, in Figure 4. Initials such as those at 25 can be applied to the top surface of any of the laminae 15 near the middle of the club head as, for' example, by means of a decalcomania. If desired, the initials may be inlaid in a particular lamina and other laminae stacked above and below it. The cellulosic resins such as cellulose acetate butyrate, cellulose acetate, cellulose nitrate and many of the non-cellulosic thermoplastic resins are transparent in a very considerable degree; accordingly, initials such as those represented at 25 can be seen from above-through the various laminae pigmenting the resin in the mass before it is extruded to form the sheet from which the blanks are made. Thus in the case of the club head shown in Figures 1 and 2 the laminae from top to bottom may cover the range of the solar spectrum from red to violet, the top lamina being red, the bottom lamina being violet and the intermediate laminae being of the various colors which intervene between red and violet in the solar spectrum. In the same fashion, striped effects may be produced by alternating laminae of contrasting colors.
If desired, the laminae may run at an angle to the horizontal, as in Figures 5 and 6, in the first of which the laminae run vertically and in the second of which they describe an angle of 45 degrees. In the club head of Figure 5, generally designated 30, the toe end portion 31, heel end portion 32, sole surface 33 and impact face 34 correspond to the like parts in the club head of Figures 1 and 2; however, laminae 35 run vertically instead of horizontally. In the club head 40 of Figure 6, which has a toe end portion 41, a heel end portion 42, a sole surface 43 and an impact face 44, the laminae 45 extend in a direction paralleling the axis of the shaft, although they could of course extend in a direction transverse to the axis of the shaft. In either case, possibilities for personalization are much as before, although it may be necessary to view the initials or symbol from a different angle, normally at right angles to the planes of the laminae, to get the personalized effect.
In the golf club head of Figure 7, designated 50', there is as before a toe end portion 51, a heel end portion 52, a sole surface 53 and an impact face 54. Laminae 55 extend vertically as in the club head of Figure 5; however, they are separated from each other by metal laminae 56, introduced for weighting purposes. Such laminae may be of stainless steel or of a non-ferrous metal such as brass, bronze, copper, aluminum or the like. In Figure 8, which is a more or less diagrammatic representation of a laminate of the kind referred to, recesses 57 can be seen toward the right-hand side of the figure in metal lamina 56.
These recesses, which normally extend as apertures entirely through the thickness of the stock of which the metal laminae are made, are provided for the purpose of enabling the thermoplastic resin to flow into the openings formed by the recesses or apertures. In practice, a stack of laminae, relatively light plastic laminae 55 alternating with relatively heavy metal laminae 56, is heated to a temperature sutficient to soften the resin, after which the stack is subjected to pressure to force part of the material of the resin laminae into recesses 57 in the metal laminae. After the parts have had time to cool and set, the pressure is removed, leaving a laminate in which the resin layers are mechanically interlocked with the metal layers.
It is apparent that the invention lends itself to numerous variations most of which have in common the fact that the edges of the laminae are presented endwise to the impact face of the club head. This gives the localized improvement in impact resistance values that it is possible to have if an extruded thermoplastic resin is used as described. In addition to the various cellulosic resins already mentioned, it is possible to employ such other thermoplastic resins as the polyamides (nylon), the acrylic resins such as polymethyl methacrylate, and the various vinyl resins such as the polymers of vinyl chloride, vinyl acetate and the various vinyl acetals.
It is intended that the patent shall cover, by summarization in appended claims, all features of patentable novelty residing in the invention.
What is claimed is:
1. A golf club head characterized by a high degree of resistance to impact comprising a synthetic resinbody portion having a toe end, a heel end, a longitudinally extending sole surface, a longitudinally extending impact face defining a dihedral angle with the sole surface, and, extending downward at an angle to the sole surface, an open bore for the reception of a shaft, said body portion being formed of a multiplicity of relatively heavy metal laminae in alternating arrangement with relatively light laminae of extruded thermoplastic resin characterized by a microscopic grain oriented in the direction of extrusion, which laminae are arranged in parallel with each other, the edges of which laminae form the impact face, and in which laminae the direction of the grain in the resin is toward the impact face.
2. A golf club head as in claim 1 in which the laminae are so arranged that when the golf club head is viewed from either side or end the edges of the laminae are seen to extend horizontally.
3. A golf club head as in claim 1 in which the laminae are so arranged that when the golf club is viewed from either side the laminae are seen to extend vertically.
4. A golf club head as in claim 1 in which the laminae are so arranged that when the golf club head is viewed from either side the laminae are seen to extend at an angle to the vertical.
5. A golf club head comprising a body portion formed of parallel laminae having a forward end, a rearward end, a longitudinally extending sole surface, and, defining a dihedral angle with the sole surface, a longitudinally extending impact face, said impact face consisting of the exposed edges of laminae in alternating arrangement some of which are of a relatively heavy metal and others of which are of a relatively light extruded thermoplastic resin characterized by a microscopic grain oriented toward such impact face.
6. A golf club head as in claim 5 in which the metal laminae are of a stainless ferrous metal alloy.
7. A golf club head as in claim 5 in which the metal laminae are of non-ferrous metal.
8. A golf club head as in claim 7 in which the metal laminae are of aluminum.
9. A golf club head as in claim 7 in which the metal laminae are of brass.
10. A golf club head comprising a laminated body portion having a forward end, a rearward end, a longitudinally extending sole surface, and, defining a dihedral angle with the sole surface, a longitudinally extending impact face consisting of the exposed edges of parallel laminae in alternating arrangement certain of which are of relatively heavy metal and the remainder of which are of relatively light synthetic resin, said metal laminae being recessed and, where recessed, largely occupied by resin from adjacent synthetic resin laminae.
References Cited in the file of this patent UNITED STATES PATENTS 1,501,344 Hubbard July 15, 1924 1,864,513 Balch June 28, 1932 1,994,149 Root Mar. 12, 1935 2,307,193 Bellis Jan. 5, 1943 2,361,068 Sollid Oct. 24, 1944 2,386,552 Hill Oct. 9, 1945 2,534,947 Bright Dec. 19, 1950 2,550,846 Milligan May 1, 1951 2,654,608 Liebers Oct. 6, 1953 FOREIGN PATENTS 21,656 Great Britain 1909 479,508 Great Britain May 2, 1936 OTHER REFERENCES Modern Plastics Encyclopedia, 1947, pp. 706 and 707.