Patent Application
20070026964
This invention relates generally to golf equipment and, in particular, to a golf club head having a face insert.
It is generally accepted among golfers that the tactile feedback to the golfer's hands (the “feel” of a club) is improved for many clubs by the incorporation of a properly engineered polymer insert in the striking face of the club. Softer polymers produce a desirable soft feel but generally suffer from poor durability. Harder polymers have good durability and produce a more pleasing acoustic feedback but lack the soft feel of the less durable soft polymers.
U.S. Pat. No. 5,921,871 to Fisher (“the '871 patent”) discloses a golf putter head in which the striking face is formed by a laminate consisting of a plurality of pads that provide different hardnesses to suit different strokes of different golfers. The laminates are bonded together by adhesive layers and, therefore, the vibration dampening characteristics of the laminates are degraded by the intervening adhesive layers. Additionally, the laminate forming the striking face is in direct contact with the metal club head and, therefore, not fully isolated from the metal club head.
U.S. Pat. No. 6,238,302 to Helmstetter, et al. (“the '302 patent”) discloses a golf club head with a polymer face insert. The face insert is disposed in a cavity formed in the club head face. The insert has a plurality of tabs formed on its perimeter edge that engage the walls of the cavity to center the insert in the cavity. The insert is installed by bonding it to the club head using an adhesive disposed in the cavity. During assembly, as the insert is placed in the cavity, the tabs permit air and any excessive adhesive to escape the cavity through the gaps through the tabs, thereby promoting a good structural bond between the insert and the golf club head. The insert is formed of a single polymer and, therefore, the material choice must necessarily be a compromise between a harder material with greater durability and a softer material with a better feel. U.S. Pat. No. 6,729,972 to Boord (“the '972 patent”) discloses a putter having a face insert formed of at least two laminates. The outer laminate is transparent so as to reveal indicia printed on the immediately underlying laminate. As with the '871 patent, the laminate forming the striking surface is in direct contact with the metal club head along its perimeter surface and, therefore, is not fully isolated from the club head body.
The present invention comprises a golf club head including a body having a front surface with a cavity formed therein. A face insert is mounted in the cavity. In an illustrative embodiment of the present invention, the face insert comprises an insert core that is made of a relatively hard (high durometer) durable polymer material that is surrounded on at least its rear and side surfaces by an insert shell made of a second softer (lower durometer) polymer material. The insert shell allows the harder insert core to “float” within the body cavity surrounded on all sides by the softer insert shell. This arrangement of the insert core and the insert shell provides the advantages of a durable impact surface for desirable acoustic feedback while at the same time resulting in desirable feel due to the softer insert shell surrounding the harder insert core.
The present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawing figures in which like references designate like elements, and in which:
The drawing figures are intended to illustrate the general manner of construction and are not necessarily to scale. In the description and in the drawing figures, specific illustrative examples are shown and herein described in detail. It should be understood, however, that the drawing figures and detailed description are not intended to limit the invention to the particular form disclosed but are merely illustrative and intended to teach one of ordinary skill how to make and/or use the invention claimed herein and for setting forth the best mode for carrying out the invention.
With reference to
The body 12, including the cavity 24, is typically formed by an investment casting process. The bottom wall 26 and side wall 28 are then shaped by a milling process to maintain precise tolerances. The body 12 is preferably made of suitable metal material such as steel or bronze. A face insert 30 is disposed in the cavity 24 and secured thereto by an adhesive layer 32 disposed between bottom wall 26 and face insert 30.
As shown more fully in
Insert shell 36 is preferably formed of a polymer having a hardness that is less than the hardness of insert core 34, preferably less than 60D, more preferably between 55D and 45D, and most preferably about 52D durometer and is formed by an injection molding process as described more fully hereinafter. Insert shell 36 surrounds and substantially encapsulates at least the rearward surface 40 and perimeter surface 42 of insert core 34 as well as crown tabs 44, sole tab 46, heel tab 48, and toe tab 50. Insert shell 36 has an exterior surface 68 that is in contact with adhesive 32 when face insert 30 is assembled to body 12. Insert shell 36 further comprises an interior surface 70 that is in contact with rearward surface 40 of insert core 34 as well as a side surface 72 that is in contact with and surrounds perimeter surface 42 of insert core 34. The border surface 74 of insert shell 36 contacts side wall 28 of body 12 when insert 30 is assembled in body 12.
With further reference to
Alternatively, the tabs 44, 46, 48 and 50 could be replaced by a plurality of retractable pins (not shown) in the mold cavities 78. These retractable pins would retract during the molding process of the face insert 30 so that the harder insert core 34 is completely encapsulated by the softer insert shell 36.
