Patent Application
20120135819
This specification relates to golf clubs and in particular to golf club heads and face inserts composed in part of electroformed fine-grained materials.
The following background discussion is not an admission that anything discussed below is citable as prior art or common general knowledge. The documents listed below are incorporated herein in their entirety by this reference to them.
Golf club heads often utilize face inserts made of high strength, light weight materials, such as titanium alloys, to allow a portion of the mass of the golf club head to be redistributed to the perimeter or the sole of the club head while still providing a high strength surface for striking the golf ball.
Recent developments in golf club head design include face inserts made from lightweight substrate materials, such as aluminum or polymer materials, that are coated or plated with a fine-grained metallic material. The resulting composite provides high strength and durability with relatively low weight.
A problem with such face inserts is that high precision features defined in the substrate material, such as the grooves often found on iron-type golf club heads, may not be reliably coated within precise tolerances by the electrodeposition of the fine-grained metallic material. As a result, the surface of the face insert may require an added step of machining following application of the fine-grained metallic coating to define the high precision features within the precise tolerances desired in the face insert.
The surface geometry of the striking face of the golf club head, such as the depth, width and sharpness of the edges of the grooves, can have a profound effect on the degree of control that a golfer can have when striking a golf ball. The rules of golf place restrictions on the geometric dimensions of grooves and other formations defined in the face of certain golf club heads (see for example the Rules of Golf set by the United States Golf Association (USGA)).
It is desirable that golf club heads and face inserts for golf club heads have surface formations that conform closely to the geometric dimensions permitted by the rules of golf, or that otherwise include high precision geometric features, while still utilizing high strength fine-grained metallic materials. It is further desirable that such golf club heads and face inserts be formed of components that do not require the added step of machining the surface of the face insert following application of the fine-grained metallic coating.
In one aspect the invention provides a face insert for a golf club head, comprising:
a substrate; and
an electroform securely connected to said substrate, said electroform comprising a fine-grained metallic material having an average grain size that is in the range of 2 nm to 5000 nm, a yield strength that is in the range of 200 MPa to 2,750 MPa, a hardness that is in the range of 100 Vickers to 2,000 Vickers, a thickness that is in the range of 30 microns to 1 cm, and a modulus of resilience that is in the range from 0.25 MPa to 25 MPa.
In another aspect the invention provides a golf club head comprising:
a body; and
a face insert that is securely connected to said body, said face insert including:
a substrate; and
an electroform securely connected to said substrate, said electroform comprising a fine-grained metallic material having an average grain size that is in the range of 2 nm to 5000 nm, a yield strength that is in the range of 200 MPa to 2,750 MPa, a hardness that is in the range of 100 Vickers to 2,000 Vickers, a thickness that is in the range of 30 microns to 1 cm, and a modulus of resilience that is in the range from 0.25 MPa to 25 MPa.
In another aspect the invention provides a golf club head comprising:
a body having a support surface; and
an electroform securely connected to said support surface, said electroform comprising a fine-grained metallic material having an average grain size that is in the range of 2 nm to 5000 nm, a yield strength that is in the range of 200 MPa to 2,750 MPa, a hardness that is in the range of 100 Vickers to 2,000 Vickers, a thickness that is in the range of 30 microns to 1 cm, and a modulus of resilience that is in the range from 0.25 MPa to 25 MPa.
Other aspects and features of the teachings disclosed herein will become apparent, to those ordinarily skilled in the art, upon review of the following description of the specific examples of the specification.
The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification and are not intended to limit the scope of what is taught in any way. For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements.
a)-5(e) are front views of golf club heads and face inserts in accordance with the present invention showing different types of formations defined in the face inserts;
Various apparatuses or methods will be described below to provide examples of the claimed invention. The claimed invention is not limited to apparatuses or methods having all of the features of any one apparatus or method described below or to features common to multiple or all of the apparatuses described below. The claimed invention may reside in a combination or sub-combination of the apparatus elements or method steps described below. It is possible that an apparatus or method described below is not an example of the claimed invention. The applicant(s), inventor(s) and/or owner(s) reserve all rights in any invention disclosed in an apparatus or method described below that is not claimed in this document and do not abandon, disclaim or dedicate to the public any such invention by its disclosure in this document.
A golf club head in accordance with one aspect of the present invention is shown generally at 10 in
Golf club head 10 includes a body 12 and a face 14. Body 12 may be a unitary piece of material or may be formed by a number of connected pieces. A hosel 16 extends from the golf club head 10 for connecting in known manner to a shaft as shown in more detail in
The face 14 of the golf club head 10 is comprised at least in part of a face insert 18 that is securely connected to the body 12 as described in more detail below. “Securely connected” is defined herein to mean a connection that is sufficiently strong to withstand the forces normally associated with the intended use of a golf club.
Face insert 18 includes a back face 20 that is disposed on a support surface 22 defined in body 12. Face insert 18 may be disposed to lay flush in a cavity 24 defined in body 12 to define a portion of the face 14 of the golf club head (as shown in
Face insert 18 includes a front face 26 that has one or more types of formations 28 defined therein. As shown in
The rules governing the parameters for surface formations in golf club heads have changed, and may continue to change, to account for new materials and developments in club head design. The present invention allows club head designers to produce golf club heads with precise formations in the club face within the most current parameters prescribed by the rules of golf or within design parameters desired by the club head designer.
Referring to
Formations 28 may also include more complex formations such as surface structures 38 formed specifically to impart superhydrophobic character to the surface as described in more detail below. Formations 28 may further include other geometric formations desired by the golf club head designer including geometric formations such as described in U.S. Pat. No. 7,445,561 (Newman et al) which is incorporated in its entirety herein by reference.
Referring to
Each protrusion may further include nano-scale features 74 to define a roughened texture. These may comprise a plurality of nano-scale grooves extending parallel to each other or distinct nano-scale indentations. The nano-scale features are preferably within the range of 4-1000 nm in width, height and spacing and preferably have a large aspect ratio.
The protrusions 70 are spaced to define cavities 76 between protrusions to define pockets for trapping air. The micro-scale protrusions are preferably spaced by a distance that is smaller than the width of droplets of water to deter water droplets from falling between protrusions 70.
Conventional methods of forming golf club heads or face inserts and other components for golf club heads with fine-grained metallic materials utilize an electroless or electrolytic plating process to plate such materials directly onto a substrate that forms part of the golf club head or face insert. The substrate includes grooves or other formations defined in the surface that is plated with the fine-grained metallic materials. The plated surface of the golf club heads or face inserts may then require machining to ensure that the grooves or other formations that have been plated with the fine-grained metallic material fall within the geometrical dimensions and tolerances required by the rules of golf or otherwise desired by the golf club head designer.
The present invention instead utilizes an electroforming process to form an electroform comprised of fine-grained metallic material. The electroforming process involves the deposition of fine-grained metallic materials onto a mandrel that is configured to precisely define the desired geometrical features in the electroformed article such that post-process machining is no longer required. An “electroform” is defined herein to mean an article that is formed by electrodeposition of a material onto a mandrel where the mandrel does not form part of the final article.
Referring to
The mandrel 40 may be formed of a conductive material, such as titanium or stainless steel, or a non-conductive material such as a filled or unfilled polymer that is covered with a conductive coating. The surface area of the mandrel located between the forms 41 is preferably masked with a non-conductive tape or covered with a non-conductive shield (such as a plastic shield with openings cut out to reveal each form 41) in order that the fine-grained material is only electrodeposited onto the forms 41. Mandrel 40 is placed into an electrolytic bath so that fine-grained metallic material may be electrodeposited to a desired thickness onto the surface of the mandrel 40 to form electroforms 50.
The fine-grained metallic materials are preferably metals or alloys selected from Cu, Co, Cr, Ni, Fe, Sn, Mo, Zn, Au, Pd, Rh, Ru, Ag and Pt optionally with at least 5% by volume particulate dispersed therein. The particulate can be selected from the group of metal powders, metal alloy powders, and metal oxide powders of Ag, Al, Co, Fe, Cu, In, Mg, Ni, Si, Sn, Pt, Ti, V, W and Zn; nitrides of Al, B, Si and Ti; C (graphite, carbon, carbon nanotubes, or diamond); carbides of B, Cr, Bi, Si, Ti, W; MoS2; ceramics, glass and organic materials such as PTFE and other polymeric materials (PVC, PE, PP, ABS). The particulate average particle size is typically below 10 microns and preferably below 500 nm.
The fine-grained electroformed materials of this invention have an average grain size that is in the range of 2 nm to 5000 nm, a yield strength that is in the range of 200 MPa to 2,750 MPa, a hardness that is in the range of 100 Vickers to 2,000 Vickers, and a thickness that is in the range from 30 microns to 1 cm. To ensure component reliability, it is preferable to maintain the average electroform thickness to average grain size ratio at a minimum value of 10, and preferably in the range of 1,000 to 10,000,000.
The rebound distance of an object, such as a golf ball, when it impacts a certain material is a function of the modulus of resilience, Ur, of the material, which is expressed as:
U
r=½σyεy=σy2/2E
(Metals Handbook, Ninth Edition, Volume 8, Mechanical testing, American Society for Metals, Materials Park, Ohio, 44073) where εy is the maximum true strain at the yield point, σy represents the yield strength and E the modulus of elasticity. The current invention is directed to fine-grained electroformed materials having a modulus of resilience that is in the range from 0.25 MPa to 25 MPa.
Low damping characteristics (low absorption and high re-release of energy) ensure that even after high impact load and stress deformation the material springs back as desired on the striking face of golf club heads. Conventional metals have elastic strain limits of 1% or less. The current invention is directed to fine-grained electroformed materials having an elastic limit that is preferably in the range of 0.5% to 2%.
Electroform 50 may be further strengthened by a heat-treatment process subsequent to formation of the electroform. The heat-treatment process is chosen according to the chemical composition of the electroform material and the strength/hardness desired. Typical heat-treatments for the electroform materials contemplated for the present invention range from 150-700° C. for 3 sec-48 hrs.
Each electroform 50 conforms to the surface of each corresponding form 41 of the mandrel 40 including the protrusions 42 and (where applicable) recesses 43. When each electroform 50 is removed from each corresponding form 41 of the mandrel 40, a reverse image of the protrusions 42 and (where applicable) recesses 43 is defined in the electroform 50. In this manner, formations 28 and other desired structural features may be defined in electroforms 50 for face inserts 18 or other golf club head components.
Electroform 50 preferably has a thickness of at least 0.030 mm and more preferably 0.05 mm or more, a grain size of less than 10 microns and more preferably in the range of 2-5000 nm and a modulus of resilience of at least 0.25 MPa. The average thickness to grain size ratio of electroform 50 is greater than 25 and more preferably is greater than 500.
Each electroform 50 may be removed from mandrel 40 and subsequently connected to a corresponding substrate 54 using fastener 52. Alternatively, a substrate 54 may be connected to each electroform 50 using fastener 52 prior to electroforms 50 being removed from mandrel 40. The perimeter edge of each electroform may require trimming or grinding to remove excess material deposited during the electroforming process.
Electroform 50 is “securely connected” to substrate 54. “Securely connected” is defined herein to mean a connection that is sufficiently strong to withstand the forces normally associated with the intended use of a golf club. Fastener 52 may include a bonding layer formed of an epoxy or other bonding material as described further below. Fastener 52 may also, or alternatively, include various forms of mechanical connection as described in more detail below. Conventional means of fastening face inserts to the bodies of golf club heads, that are known to be sufficiently strong to withstand the forces normally associated with the intended use of a golf club, may be applied for this purpose.
Substrate 54 is preferably formed from a lightweight and durable material which may comprise a metallic material (such as metals or alloys including steel, aluminum, titanium, magnesium, and copper) or other lightweight materials such as fibre-reinforced composites or filled or unfilled polymer materials e.g., a carbon fiber/epoxy resin composite, polyamide, glass filled polyamide, polyester, polythalamide, polypropylene, polycarbonate, polyvinyl chloride (PVC), thermoplastic polyolefins (TPOs), filled acrylonitrile-butadiene-styrene (ABS) or unfilled acrylonitrile-butadiene-styrene (ABS).
Substrate 54 includes a first surface 56 that may be roughened by mechanical, chemical, electrochemical or plasma etching means to improve adhesion with fastener 52 when a bonding material is utilized.
Bonding material is selected according to the material used for substrate 54 in order to achieve an optimum bond. For metallic substrate materials, the bonding material is preferably formed of an epoxy adhesive, double sided adhesive tape or solder alloy. Most preferably for metallic substrates the bonding material is formed of 3M DP420™ epoxy adhesive or Indalloy #282™ solder alloy. For polymer or carbon fibre substrate materials, the bonding material is preferably formed of epoxy adhesive or double sided adhesive tape and most preferably one of 3M 966™, 3M 9460™ and 3M 9469™ epoxy adhesives.
As noted above, additional or alternative means for connecting electroform 50 to substrate 54 may include various forms of mechanical connection including set screws, clips or an interference fit. For instance, referring to
The completed face insert 18 is securely connected to support surface 22 of body 12 using a fastener 58 that may include a bonding material such as an epoxy adhesive, double sided adhesive tape or solder alloy. Alternatively, or in addition to utilizing a bonding material, fastener 58 may include screws, bolts, rivets, dowel pins or other suitable connecting structures formed in face insert 18 and body 12, such as tabs and slots or snap fit components.
Referring to
As shown in
Referring to
Referring to
A golf club in accordance with the present invention is shown generally at 100 in
While the above description provides examples of one or more processes or apparatuses, it will be appreciated that other processes or apparatuses may be within the scope of the accompanying claims.
