Patent Publication Number: US-11660511-B2

Title: Mixed material golf club head

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 16/723,065, filed on Dec. 20, 2019, which is a continuation-in-part of U.S. patent application Ser. No. 16/714,109, filed on Dec. 13, 2019 and is now U.S. Pat. No. 10,940,373, which claims the benefit of U.S. Provisional Appl. No. 62/779,335, filed on Dec. 13, 2018, and which is a continuation-in-part of U.S. patent application Ser. No. 16/380,873, filed on Apr. 10, 2019 and is now U.S. Pat. No. 10,765,922, which is a continuation of U.S. patent application Ser. No. 15/901,081, filed on Feb. 21, 2018 and is now U.S. Pat. No. 10,300,354, which is a continuation of U.S. patent application Ser. No. 15/607,166, filed on May 26, 2017 and now U.S. Pat. No. 9,925,432, which claims the benefit of U.S. Provisional Appl. No. 62/342,741, filed on May 27, 2016, the contents of all of which are incorporated fully herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates generally to a golf club head with a mixed material construction. 
     BACKGROUND 
     In general, there are many important physical parameters (i.e., volume, mass, etc.) that effect the overall performance of a golf club head. One of the most important physical parameters, is the total mass of the golf club head. The total mass of the golf club head is the sum of the total structural mass and the total discretionary mass. Structural mass generally refers to the mass of the materials that are required to provide the club head with the structural resilience needed to withstand repeated impacts. Structural mass is highly design-dependent and provides a designer with a relatively low amount of control over specific mass distribution. Conversely, discretionary mass is any additional mass (beyond the minimum structural requirements of the golf club head) that may be added to the club head design for the sole purpose of customizing the performance and/or forgiveness of the club. There is a need in the art for alternative designs to all metal golf club heads to provide a means for maximizing discretionary weight to maximize club head moment of inertia (MOI) and lower/back center of gravity (CG). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       This disclosure relates generally to sport equipment and relates more particularly to golf club heads and related methods. 
         FIG.  1    illustrates a bottom view of a mixed material golf club head. 
         FIG.  2    illustrates a top view of the golf club head of  FIG.  1   . 
         FIG.  3    illustrates a rear view of the golf club head of  FIG.  1   . 
         FIG.  4    illustrates an exploded view of the golf club head of  FIG.  1   . 
         FIG.  5    illustrates a front planar view of the golf club head of  FIG.  1   . 
         FIG.  6    illustrates rear planar view of a front body of the golf club head of  FIG.  1   . 
         FIG.  7    illustrates a rear view of the front body of the golf club head of  FIG.  1   . 
         FIG.  8    illustrates an exploded view of the front body and a rear body of the golf club head of  FIG.  1   . 
         FIG.  9    illustrates a cross sectional view of the golf club head of  FIG.  1   . 
         FIG.  10    illustrates an enlarged view of a weight pad and a weight in the golf club head of  FIG.  1   . 
         FIG.  11    illustrates an assembly view of a weight, a fastener, and a washer in the golf club head of  FIG.  1   . 
         FIG.  12    illustrates an internal view of the rear body of the golf club head of  FIG.  1   . 
         FIG.  13    illustrates an alternate internal view of the rear body of the golf club head of  FIG.  1   . 
         FIG.  14    illustrates another alternate internal view of the rear body of the golf club head of  FIG.  1   . 
         FIG.  15    illustrates is a schematic flow chart illustrating a method of manufacturing of the golf club head of  FIG.  1   . 
     
    
    
     Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings. 
     DESCRIPTION 
     Described herein is a golf club head that comprises a mixed material rear body in combination with a metallic front body, comprising a strike face and surrounding frame. The mixed material rear body is comprised of a fiber reinforced thermoplastic composite resilient layer, a molded thermoplastic structural layer, a metallic weight pad, and a metallic weight secured within the metallic weight pad. The mixed material rear body construction provides a significant reduction in structural mass, allowing for improved allocation of discretionary mass, thus improvements in the MOI and CG of the golf club head. 
     The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “include,” and “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus. 
     The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the apparatus, methods, and/or articles of manufacture described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. 
     Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. 
     Described herein are various embodiments of a golf head having a mixed material construction. The mixed material construction comprises a metallic front body and a mixed material rear body. One embodiment of the club head includes a composite rear body with a metallic weight pad. In these or other embodiments, the rear body of the club head can include a fiber reinforced thermoplastic composite resilient layer, a molded thermoplastic structural layer, and a metallic weight secured within the metallic weight pad. In many embodiments, the golf club head can be wood-type golf club head (i.e. driver, fairway wood, hybrid). 
     In some embodiments, the club head can comprise a driver. In these embodiments, the loft angle of the club head can be less than approximately 16 degrees, less than approximately 15 degrees, less than approximately 14 degrees, less than approximately 13 degrees, less than approximately 12 degrees, less than approximately 11 degrees, or less than approximately 10 degrees. Further, in these embodiments, the volume of the club head can be greater than approximately 400 cc, greater than approximately 425 cc, greater than approximately 450 cc, greater than approximately 475 cc, greater than approximately 500 cc, greater than approximately 525 cc, greater than approximately 550 cc, greater than approximately 575 cc, greater than approximately 600 cc, greater than approximately 625 cc, greater than approximately 650 cc, greater than approximately 675 cc, or greater than approximately 700 cc. In some embodiments, the volume of the club head can be approximately 400 cc-600 cc, 425 cc-500 cc, approximately 500 cc-600 cc, approximately 500 cc-650 cc, approximately 550 cc-700 cc, approximately 600 cc-650 cc, approximately 600 cc-700 cc, or approximately 600 cc-800 cc. 
     In some embodiments, the club head can comprise a fairway wood. In these embodiments, the loft angle of the club head can be less than approximately 35 degrees, less than approximately 34 degrees, less than approximately 33 degrees, less than approximately 32 degrees, less than approximately 31 degrees, or less than approximately 30 degrees. Further, in these embodiments, the loft angle of the club head can be greater than approximately 12 degrees, greater than approximately 13 degrees, greater than approximately 14 degrees, greater than approximately 15 degrees, greater than approximately 16 degrees, greater than approximately 17 degrees, greater than approximately 18 degrees, greater than approximately 19 degrees, or greater than approximately 20 degrees. For example, in some embodiments, the loft angle of the club head can be between 12 degrees and 35 degrees, between 15 degrees and 35 degrees, between 20 degrees and 35 degrees, or between 12 degrees and 30 degrees. 
     In embodiments where the club head comprises a fairway wood, the volume of the club head is less than approximately 400 cc, less than approximately 375 cc, less than approximately 350 cc, less than approximately 325 cc, less than approximately 300 cc, less than approximately 275 cc, less than approximately 250 cc, less than approximately 225 cc, or less than approximately 200 cc. In these embodiments, the volume of the club head can be approximately 150 cc-200 cc, approximately 150 cc-250 cc, approximately 150 cc-300 cc, approximately 150 cc-350 cc, approximately 150 cc-400 cc, approximately 300 cc-400 cc, approximately 325 cc-400 cc, approximately 350 cc-400 cc, approximately 250 cc-400 cc, approximately 250 cc-350 cc, or approximately 275 cc-375 cc. 
     In some embodiments, the club head can comprise a hybrid. In these embodiments, the loft angle of the club head can be less than approximately 40 degrees, less than approximately 39 degrees, less than approximately 38 degrees, less than approximately 37 degrees, less than approximately 36 degrees, less than approximately 35 degrees, less than approximately 34 degrees, less than approximately 33 degrees, less than approximately 32 degrees, less than approximately 31 degrees, or less than approximately 30 degrees. Further, in these embodiments, the loft angle of the club head can be greater than approximately 16 degrees, greater than approximately 17 degrees, greater than approximately 18 degrees, greater than approximately 19 degrees, greater than approximately 20 degrees, greater than approximately 21 degrees, greater than approximately 22 degrees, greater than approximately 23 degrees, greater than approximately 24 degrees, or greater than approximately 25 degrees. 
     In embodiments where the club head comprises a hybrid, the volume of the club head is less than approximately 200 cc, less than approximately 175 cc, less than approximately 150 cc, less than approximately 125 cc, less than approximately 100 cc, or less than approximately 75 cc. In some embodiments, the volume of the club head can be approximately 100 cc-150 cc, approximately 75 cc-150 cc, approximately 100 cc-125 cc, or approximately 75 cc-125 cc. 
       FIG.  1 - 10    illustrate an embodiment of a golf club head  100  having a metallic front body  104 , and a rear body  108 . The front body  104  and rear body  108  are secured together to define a substantially closed/hollow interior volume. As is conventional with wood-style golf heads, the golf club head  100  includes a crown  112 , a sole  116 , and can be divided into a heel region  124  and a toe region  128 . 
     In some embodiments, the golf club head  100  comprises a metallic front body  104 , and a composite rear body  108 , wherein the rear body comprises a woven fiber reinforced thermoplastic resilient layer  148 , a molded thermoplastic structural layer  152 , and a metallic weight pad  156 . The combination of a woven fiber reinforced thermoplastic resilient layer  148  and a molded thermoplastic structural layer  152 , enables savings in structural mass, in comparison to a similar club head made entirely from metal. 
     The structural weight savings achieved by using a resilient layer  148  and a structural layer  152 , can be used to either reduce the entire weight of the club head  100  (which may provide faster club head speed and/or long hitting distances) or to increase the amount of discretionary mass that is available for placement on the golf club head  100 . In one embodiment, the additional discretionary mass, gained from using a composite resilient layer  148  and a composite structural layer  152 , can be reintroduced into the club head  100  in the form of a metallic weight pad  156 . The combination of a light composite rear body  108  and metallic weight pad  156 , allow the club head  100 , to allocate a majority of the mass of the club head in a position to maximize the MOI and CG, leading to more forgiveness and longer shots. 
     I. Front Body 
     Referring to  FIGS.  4 - 7   , the front body  104  of the club head  100  comprises a strike face  120 , intended to impact a golf ball. The front body  104  comprises a surrounding frame  136  that extends rearward from a perimeter  140  of the strike face  120 , to provide the front body  104  with a cup-shaped appearance. The surrounding frame  136  comprises an internal surface  170  and an external surface  172 . Furthermore, the surrounding frame  136  can comprise a flange  174 , to provide an attachment surface to connect the front body  104  and the rear body  108 . When the front body  104  is combined with the rear body  108 , the external surface  172  of the front body  104  forms a portion of the crown  112  and the sole  116  of the club head  100 . The front body  104  further comprises a hosel  144  for receiving a golf club shaft or shaft adapter in the heel region  124  of the golf club head  100 . 
     In some embodiments, the strike face  120  and surrounding frame  136  can be integrally formed. In other embodiments, the strike face  120  and surrounding frame  136  can be separately formed and joined together. In one embodiment, the strike face  120  is forged and the surrounding frame  136  is cast, then the strike face  120  and surrounding frame  136  are joined through welding, brazing, plasma welding, low-power laser welding, forging, or another suitable joining technique. 
     In many embodiments, the front body  104  is made from a metallic material to withstand the repeated impact stress from striking a golf ball. In some embodiments, the front body  104 , can be formed from stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), an aluminum alloy, or a composite material. In some embodiments, the strike face  120  of the golf club head  100  can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), an aluminum alloy, an amorphous metal alloy, or a composite material. 
     The front body  104  comprises a mass. In some embodiments, wherein the strike face  120  and surrounding frame  136  are separate, the mass of the front body  104  is the sum of the mass of the strike face  120  and the mass of the surrounding frame  136 . Depending on the material the front body  104  is made of, the mass of the front body  104  can range between 40 grams and 140 grams. In most embodiments, the mass of the front body  104  does not exceed 140 grams. In some embodiments, the mass of the front body  104  can range between 40-50 grams, 50-60 grams, 60-70 grams, 70-80 grams, 80-90 grams, 90-100 grams, 100-110 grams, 110-120 grams, 120-130 grams, or 130 grams-140 grams. 
     a. Strike Face 
     Referring to  FIGS.  5 ,  6 , and  9   , the front body  104  of the golf club head  100  comprises a strike face  120 , positioned to strike a golf ball. The strike face  120  comprises a centerpoint  160 , a loft plane  164 , and a midplane  168 . The center point  160  is equidistant from the from the crown  112  and sole  116  of the club head  100 , and equidistant from the edge of the face that is the most proximate to the toe region  128  and from the edge of the face that is the most proximate to the heel region  124 . The loft plane  164  is tangent to the centerpoint  160  of the strike face  120  of the club head  100 . The loft plane  164  intersects a ground plane  180 . 
     The strike face  120  of the club head  100  comprises a thickness measured as the distance between the strike face  120  and the internal surface  170  of the front body  104 . The thickness of the strike face  120  varies at different locations defining a variable face thickness (VFT) or variable thickness profile  196 . The variable thickness profile  196  having a central region  192  and a peripheral region  188 . In many embodiments, the central region  192  of the variable thickness profile  196  comprises an ellipse or oval or ovoid or egg-like shape. The central region  192  is generally oblong and extends from a portion of the strike face  120  near the sole  116  and heel region  124  to a portion of the strike face  120  near the toe region  128  and crown  112 . 
     Referring to  FIG.  6   , the central region  192  extends over or is positioned on or near the centerpoint  160  of the strike face  120  such that the center point  160  of the strike face  120  is located in the central region  192 . The central region  192  comprises a maximum thickness of the strike face  120 . In many embodiments, the thickness of the central region  192  is substantially constant. The peripheral region  188  is positioned around the perimeter  140  of the strike face  120  and comprises a minimum thickness of the strike face  120 . In many embodiments, the thickness of the peripheral region  188  is substantially constant. The thickness of the strike face  120  in the central region  192  is greater than the thickness of the strike face  120  in the peripheral region  188 . A transition region  190  is positioned between the central region  192  and the peripheral region  188 . The transient region  190  includes a varying thickness that creates a transition between the central region  192  and the peripheral region  188 . 
     Furthermore, the strike face  120  comprises a major axis  184  extending in a general heel  124  to toe  128  direction. The major axis  184  intersects the centerpoint  160  and forms an angle β with the ground plane. In many embodiments, the major axis  184  reflects the oblong shape of the central region  192 . 
     The major axis  184  forms an approximate angle of 20 degrees with the ground plane  180 . For example, the angle formed between the major axis  184  of the central region  192  and the ground plane  180  can vary from 0 to 60 degrees. In some embodiments, the angle formed between the major axis  184  of the central region  192  and the ground plane  180  can vary from 2 to 20, 2 to 30, 5 to 40, 10 to 50, or 15 to 60 degrees. In other embodiments, the major axis  184  can create an angle of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, or 60 degrees with ground plane  180 . By disposing the center region  192  on an angle it further allows the elongated portion of the egg-shape to extend towards the upper-toe portion of the strike face  120  wherein high CT values exist, thus improving resulting ball speed. 
     The oval or ovoid or egg-like shape, along with the angle of the central region  192  of the variable thickness profile  196 , enables thicker regions of the strike face  120  to be positioned in regions having inherently high CT, and thinner regions of the strike face  120  to be positioned in regions having inherently low CT. Accordingly, regions of the face having inherently high CT are reduced, and regions of the face having inherently low CT are increased, resulting in normalized CT across the strike face  120 . In many embodiments, the variable thickness profile  196  results in a range in characteristic time less than 115 micro-seconds (μs), less than 110 μs, less than 105 μs, less than 100 μs, less than 95 μs, less than 90 μs, or less than 85 μs. Further, in many embodiments, the variable thickness profile  40  results in an average characteristic time greater than 230 μs, greater than 235 μs, or greater than 240 μs. For example, in many embodiments, the average CT of the face plate  20  can be between 230 μs and 240 μs, between 235 μs and 240 μs, or between 240 μs and 245 μs. 
     Further, because the angled VFT is designed to position thickened portions of the strike face  120  in regions where it is required, the strike face  120  can experience a weight reduction compared to a strike face devoid of the variable thickness profile  196  described herein. The extra discretionary weight can be re-introduced in other regions of the club head to manipulate the club head center of gravity position and to increase club head moment of inertia, further improving the performance of the club head. In the illustrated embodiment, the club head  100  having the variable thickness profile  196 , as described herein, saves 2.1 grams of weight compared to a similar club head devoid of the variable thickness profile  196 . 
     b. Hosel 
     The front body  104  of the golf club head  100  comprises the hosel  144 . The hosel  144  includes a hosel axis  176  extending along a center of a bore of the hosel  144 . Referring to  FIGS.  3  and  6   , in the present example, a hosel coupling mechanism of the golf club head  100  comprises the hosel  144  and a shaft sleeve (not shown), where the shaft sleeve can be coupled to an end of a golf shaft (not shown). The shaft sleeve can couple with the hosel  144  in a plurality of configurations, thereby permitting the golf shaft to be secured to the hosel  144  at a plurality of angles relative to the hosel axis  176 . There can be other examples, however, where the shaft can be non-adjustably secured to the hosel  144 . In the illustrated embodiment, the hosel axis  176  is at an angle α with the ground plane  12  with respect to a front view of the golf club head  10  ( FIG.  1   ). The illustrated angle α is approximately 60-degrees, but in other constructions, the angle α may be between approximately 40-80 degrees (e.g., approximately 40 degrees, approximately 45 degrees, approximately 50 degrees, approximately 55 degrees, approximately 60 degrees, approximately 65 degrees, approximately 70 degrees, approximately 75 degrees, or approximately 80 degrees). 
     Furthermore, the hosel axis  176  and the major axis  184  form an angle θ. In many embodiments, the angle θ formed between the hosel axis  176  and the major axis  184  can range between 60 and 140 degrees. In most embodiments, the minimum angle θ formed between the hosel axis  176  and the major axis  184  is approximately 60 degrees. In some embodiments, the angle θ formed between the hosel axis  176  and the major axis  184  can range between 60-70 degrees, 70-80 degrees, 80-90 degrees, 90-100 degrees, 100-110 degrees, 110-120 degrees, 120 degrees-130 degrees, or 130-140 degrees. In one embodiment, the angle the angle θ formed between the hosel axis  176  and the major axis  184  can range between 80 degrees and 90 degrees. 
     c. Surrounding Frame 
     The front body  104  of the golf club head  100  comprises the surrounding frame  136  that extends rearward from the entire perimeter  140  of the strike face  120 . The surrounding frame  136  further comprises a flange  174  that is operative to couple the front body  104  and the rear body  108 . 
     The flange  174  provides a surface, to achieve a lap joint, wherein the rear body  108  can attach. The flange  174  extends rearward from the entire surrounding frame  136 , and forms a step-type structure, down from the external surface  172  of the surrounding frame  136 . In many embodiments, the flange  174  of the front body  104  allows the rear body to overlap the flange  174  and join to the front body  104 , by way of epoxy, adhesion, welding, bonding, laser assisted metal-plastic welding, brazing, or any other suitable attachment method. The lap joint style flange  174 , further allows the front body  104  and rear body  108  to securely mate, without the use of any mechanical fasteners. 
     Furthermore, the surrounding frame  136  comprises the external surface  172  and the internal surface  170 , wherein additional aerodynamic features can be placed, to improve the overall speed of the golf club head. The surrounding frame  136  of the front body  104  of the golf club head  100 , can include additional aerodynamic features, such as turbulators  200 . The turbulators  200  can be used to reduce club head drag and increase the speed of the club  100 . These turbulators  200  are further described in U.S. Pat. No. 9,555,294, which is incorporated by reference in its entirety. 
     II. Rear Body 
     Referring to  FIGS.  4 , and  8 - 11   , the rear body  108  of the club head  100  comprises a crown member  204 , a sole member  208 , and a weight pad  212 . The crown member  204  and sole member  208  are bonded together to form a portion of the crown  112  and the sole  116  of the golf club head  100 . When the front body  104  and rear body  108  are joined, the external surface  172  of the front body  104 , the crown member  204 , and the sole member  208 , form the entire crown  112  and sole  116  of the golf club head  100 . The sole member  208  of the rear body  108  can further comprise a composite resilient layer  152 , a composite structural layer  156 , and a metallic weight pad  212 . 
     In the present design, the rear body  108  may include a mix of molded thermoplastic materials (e.g., injection molded thermoplastic materials) and fiber reinforced thermoplastic composite materials. As used herein, a molded thermoplastic material is one that relies on the polymer itself to provide structure and rigidity to the final component. The molded thermoplastic material is one that is readily adapted to molding techniques such as injection molding, whereby the material is freely flowable when in a heated to a temperature above the melting point of the polymer. A molded thermoplastic material with a mixed-in filler material is referred to as a filled thermoplastic (FT) material. Filled thermoplastic materials are freely flowable when in a heated/melted state. To facilitate the flowable characteristic, filler materials generally include discrete particulate having a maximum dimension of less than about 25 mm, or more commonly less than about 12 mm. For example, the filler materials can include discrete particulate having a maximum dimension of 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. Filler materials useful for the present designs may include, for example, glass beads or discontinuous reinforcing fibers formed from carbon, glass, or an aramid polymer. 
     In contrast to molded and filled thermoplastic materials, fiber reinforced composite (FRC) materials generally include one or more layers of a uni- or multi-directional fiber fabric that extend across a larger portion of the polymer. Unlike the reinforcing fibers that may be used in FT materials, the maximum dimension of fibers used in FRCs may be substantially larger/longer than those used in FT materials and may have sufficient size and characteristics such that they may be provided as a continuous fabric separate from the polymer. When formed with a thermoplastic polymer, even if the polymer is freely flowable when melted, the included continuous fibers are generally not. 
     FRC materials are generally formed by arranging the fiber into a desired arrangement, and then impregnating the fiber material with a sufficient amount of a polymeric material to provide rigidity. In this manner, while FT materials may have a resin content of greater than about 45% by volume or more preferably greater than about 55% by volume, FRC materials desirably have a resin content of less than about 45% by volume, or more preferably less than about 35% by volume. FRC materials traditionally use two-part thermoset epoxies as the polymeric matrix, however, it is possible to also use thermoplastic polymers as the matrix. In many instances, FRC materials are pre-prepared prior to final manufacturing, and such intermediate material is often referred to as a prepreg. When a thermoset polymer is used, the prepreg is partially cured in intermediate form, and final curing occurs once the prepreg is formed into the final shape. When a thermoplastic polymer is used, the prepreg may include a cooled thermoplastic matrix that can subsequently be heated and molded into final shape. This technique enables complex and lightweight geometries to be made, such as the rear body  108 , without sacrificing strength. 
     a. Crown Member 
     The rear body  108 , comprises the crown member  204 . Referring to  FIGS.  4  and  9    the crown member  204  comprises an external surface  206 , such that when the rear body  108  and front body  104  are joined, the external surface  206  of the crown member  204  and the external surface  172  of the surrounding frame  136  form the entire crown  112  of the golf club head  100 . The external surface  206  of the crown member  204  comprises a generally curvilinear shape which is concave with respect to the ground plane  180 . The generally curvilinear shape of the crown member  204  allows the rear body  208  to seamlessly be joined to the front body  104 , as the crown member is placed entirely over the flange  174  of the front body  104 . 
     In many embodiments, the crown member  204  is comprised of a carbon fiber weave, devoid of any layering of composite plies or unidirectional composite plies. In one embodiment, the crown member  204  may be substantially formed from a formed fiber reinforced composite material that comprises a woven glass or carbon fiber reinforcing layer embedded in a polymeric matrix. In such an embodiment, the polymeric matrix is preferably a thermoplastic material such as, for example, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or a polyamide such as PA6 or PA66. In other embodiments, the crown member  204  may instead be formed from a filled thermoplastic material that comprises a glass bead or discontinuous glass, carbon, or aramid polymer fiber filler embedded throughout a thermoplastic material such as, for example, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or polyamide. In still other embodiments, the crown member  204  may have a mixed-material construction that includes both a filled thermoplastic material and a formed fiber reinforced composite material. 
     b. Sole Member 
     The rear body  108 , comprises the sole member  208 . Referring to  FIGS.  4  and  9    the sole member  208  comprises the structural layer  156  and the resilient layer  152 , providing a lightweight, but strong sole  116  of the golf club head  100 . In reference to the ground plane  180 , the resilient layer  152  is positioned tangent to the ground plane, and the structural layer  156  is placed on top of the resilient layer  152 , in the interior of the golf club head  100 . 
     In one embodiment, the sole member  208  has a mixed-material construction that includes both a fiber reinforced thermoplastic composite resilient layer  152  and a molded thermoplastic structural layer  156 . In a preferred embodiment, the molded thermoplastic structural layer  156  may be formed from a filled thermoplastic material that comprises a glass bead or discontinuous glass, carbon, or aramid polymer fiber filler embedded throughout a thermoplastic material such as, for example, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or a polyamide such as PA6 or PA66. The resilient layer  152  may then comprise a woven glass, carbon fiber, or aramid polymer fiber reinforcing layer embedded in a thermoplastic polymeric matrix that includes, for example, a polyphenylene sulfide (PPS), a polyether ether ketone (PEEK), or a polyamide such as PA6 or PA66. In one particular embodiment, the crown member  202  and resilient layer  152  may each comprise a woven carbon fiber fabric embedded in a polyphenylene sulfide (PPS), and the structural layer  156  may comprise a filled polyphenylene sulfide (PPS) polymer. 
     The structural layer  156  may generally include a forward portion  236  and a peripheral portion  240  that define an outer perimeter of the sole member  208 . In an assembled club head  100 , the forward portion  236  is bonded to the metallic front body  104 , and the peripheral portion  240  is bonded to the crown member  204 . The structural layer  156  defines a plurality of apertures  244  located interior to the perimeter that each extend through the thickness of the structural layer  156 . Further, the structural layer  156  may include one or more structural members  248  that extend from the forward portion  236  and between at least two of the plurality of apertures  244 . Furthermore, as described below, the structural layer  156  can be configured to comprise a metallic weight pad  212  and metallic weight  220 . 
     The resilient layer  152  may be bonded to the structural layer  156  such that it directly abuts or overlaps at least a portion of the forward portion  236 , the peripheral portion  240 , and the plurality of structural members  248 . In doing so, the resilient layer  152  may entirely cover each of the plurality of apertures  244  when viewed from the exterior of the club head  100 . Likewise, the one or more structural members  248  may serve as selective reinforcement to an interior portion of the resilient layer  244 , akin to a reinforcing rib or gusset. 
     With respect to both the polymeric construction of the crown member  204  and the sole member  208 , any filled thermoplastics or fiber reinforced thermoplastic composites should preferably incorporate one or more engineering polymers that have sufficiently high material strengths and/or strength/weight ratio properties to withstand typical use while providing a weight savings benefit to the design. Specifically, it is important for the materials of the golf club head  100  to efficiently withstand the stresses imparted during an impact between the strike face  120  and a golf ball, while not contributing substantially to the total weight of the golf club head  100 . In general, preferred polymers may be characterized by a tensile strength at yield of greater than about 60 MPa (neat), and, when filled, may have a tensile strength at yield of greater than about 110 MPa, or more preferably greater than about 180 MPa, and even more preferably greater than about 220 MPa. In some embodiments, suitable filled thermoplastic polymers may have a tensile strength at yield of from about 60 MPa to about 350 MPa. In some embodiments, these polymers may have a density in the range of from about 1.15 to about 2.02 in either a filled or unfilled state and may preferably have a melting temperature of greater than about 210° C. or more preferably greater than about 250° C. 
     c. Weight Pad 
     With reference to  FIGS.  4  and  9 - 11   , in many embodiments, the structural layer  156  can include a weight pad  212 . The weight pad  212  comprises a cavity  216  adapted to receive a metallic weight  220 . In some embodiments, the weight pad  212  is generally located toward the rear most point on the club head  100 , and therefore may be integral to and/or directly coupled with the rear portion  132  of the structural layer  156 . In some embodiments, a hole or opening  252  may be provided in the resilient layer  152 , through which a portion of the weight pad  212  may extend. In some embodiments, the opening  250  is spaced apart from the front body  104  by a minimum distance of at least 25 mm, or at least 30 mm, or at least 35 mm (i.e., measured along the outer surface of the club head). As shown in  FIG.  9   , when assembled, an outer surface of the weight pad  212  may sit flush with an outer surface of the directly adjacent sole member  208  and/or resilient layer  152 . In this manner, a portion of the weight pad  212  may form part of the eternal sole  116  of the golf club head  100 . Additionally, in some embodiments, an internal surface of the weight pad  212  may be exposed on an interior of the clubhead. The weight pad  212  functions to provide a dense rearward mass to improve the overall MOI of the golf club head. The weight pad  212  provides a portion to place a high concentration of discretionary mass, since there are substantially weight savings achieved from forming a composite rear body  108 . 
     The weight pad  212  can comprise any desired shape, in order to position as much mass towards the periphery of the rear portion  132  of the golf club head  100 . The shape of the weight pad  212  can be any one of the following shapes: circular, triangular, square, rectangular, trapezoidal, pentagonal, curvilinear, spade-shaped, or any other polygon or shape with at least one curved surface. In one embodiment, the weight pad  212  is can be a roughly trapezoidal shape. In another embodiment, the weight pad  212  can be a roughly rectangular shape. Furthermore, in another embodiment, the weight pad  212  can be a roughly circular shape. Further still, in another embodiment, the weight pad  212  can be a roughly triangular shape. 
     In most embodiments, the weight pad  212  can be made from a metallic material to provide a dense rearward portion to improve the overall MOI of the golf club head  100 . In some embodiments, the weight pad  212  can be formed from stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), an aluminum alloy, or a composite material. In one embodiment, the weight pad  212  can be made from a stainless steel. The weight pad  212  can be forged or cast, prior to being secured within the sole member  208  of the rear body  108 . 
     The weight pad  212  may be secured within the opening  250  in resilient layer  152  through via one or more techniques that are operable to provide a robust, structural bond. Due to differences in material types/material surface energies, as well as the comparatively high ratio of component mass to contact surface area, it may be difficult for conventional adhesives alone to withstand the forces experienced during a golf club impact with a ball. As such, it may be desirable to integrate at least a portion of the weight pad into the structural layer  156  and/or resilient layer  152  by encapsulating at least a portion of the weight pad. In doing so, the material strength of the encapsulating layer may be operative to provide a more durable bond than the use of surface adhesives alone. Referring to  FIGS.  9  and  13   , examples of suitable encapsulation may include structural tapes  261  extending over an edge  256  of the weight pad  212 , direct encapsulation of at least a portion of the weight pad  212  by the structural layer  156 , or encapsulation of a portion of the weight pad between adjacent plies of the resilient layer  152 . These techniques may be used instead of, or in addition to the use of chemical adhesives provided between the weight pad and sole member  208 . 
     In one configuration, the weight pad  212  may be attached to the sole member  208  without the use of any mechanical fasteners. In one embodiment, the weight pad  212  is casted and then the structural layer  156  may be molded around the at least the edge  252  of the weight pad  212 , for example, via an insert injection molding technique. As noted above, the filled thermoplastic construction of the structural layer  156  is particularly suited to receive the weight pad  212  due to its ability to form complex geometry and extend around edges in a structurally stable manner. Depending on the geometry of the weight pad, such a joining technique may be more difficult with tapes or FRCs due to their more uniform profile. 
     The cavity  216  of the weight pad  212  extends inward from weight pad  212 . In the illustrated embodiment, the cavity  216  comprises a circular shape. In other embodiments, the cavity  216  can comprise any shape. For example, the shape of the cavity  216  can comprise a circle, an ellipse, a triangle, a rectangle, an octagon, or any other polygon or shape with at least one curved surface. The cavity  216  provides a recess to affix a metallic weight  220  within. The metallic weight  220 , further adds discretionary weight to the golf club head  100 , thus further improving the MOI and CG of the golf club head  100 . Additionally, the cavity  216  and metallic weight  220  allow for changes to be made to the overall weight of the golf club head  100 , by removably attaching different metallic weights of different densities. 
     The cavity  212  includes a depth measured from a base  224  of the cavity  212  to the external contour of the sole member  208 , in a direction generally perpendicular to the base  224 . In many embodiments, the depth of the cavity  212  is between 0.10 inches and 0.50 inches. In some embodiments, the depth of the cavity  212  is less than 0.50 inches, less than 0.45 inches, less than 0.40 inches, less than 0.35 inches, less than 0.30 inches, less than 0.25 inches, less than 0.20 inches, or less than 0.15 inches. 
     Further, the cavity  212  comprises an aperture  228  in the base  224 . The aperture  228  extends inward from the base  224  of the cavity  212 , towards the crown  112  of the golf club head  100 . In some embodiments, the aperture  228  can comprise threading that mates with the threading of a fastener  230  to secure the metallic weight  220  within the cavity  216 . In other embodiments, the aperture  228  can be devoid of threading for use with a self-tapping or self-drilling fastener. 
     The metallic weight  220  is configured to be positioned with the cavity  216  of the weight pad  212 . In the illustrated embodiment, the weight  220  is circular in shape to correspond to the shape of the cavity  212 . In other embodiments, the weight  220  can comprise any geometric shape corresponding to the shape of the cavity  212  (e.g., circular, elliptical, triangular, rectangular, trapezoidal, octagonal, or any other polygonal shape or shape with at least one curved surface). 
     The metallic weight  220  further comprises an aperture  232  extending entirely through the weight  220 . The aperture  232  is substantially similar in size to the aperture  228  of the cavity  212  and the aperture  232  of the weight  220  aligns with the aperture  228  of the cavity  212 , when the weight is positioned within the cavity  212 . In most embodiments, the aperture  232  is devoid of threading to allow the fastener  230  to pass through the weight  220  and secure, via threading, to the aperture  228  of the weight pad  212 . Additionally, in some embodiments, a washer  214  can be positioned in the cavity  212  prior to the positioning of the metallic weight  220  within the cavity  212 . 
     While affixing the weight  220  and weight pad  212  to the structural layer  156  at the rear portion  132  of the club head  100  desirably shifts the center of gravity of the club head  100  rearward and lower while also increasing the club head&#39;s moment of inertia, it also can create a cantilevered point mass spaced apart from the more structural metallic front body  104 . As such, in some embodiments, the one or more structural members  248  may span between the weight pad  212 /metallic weight  220  and the front body  104  to provide a reinforced load path between the weight pad  212 , the metallic weight  220 , and the metallic front body  104 . In this manner, the one or more structural members  248  may be operative to aid in transferring a dynamic load between the weight pad  212 , the metallic weight  220 , and the front body  104  during an impact between the strike face  120  and a golf ball. Furthermore, in some embodiments, referring to  FIG.  14   , one or more structural members  248  may be upstanding and may extend from the weight pad  212  or from an edge of the opening  250  upward to/toward the crown member  204 . In this manner, this structural member  248  may serve as a gusset or strut that is operative reinforce the weight pad  212  relative to the crown member  204 . Such a structural gusset may reduce bending moments applied on the sole member  208  at/after impact by the weight pad  212 /metallic weight  220 . These same rib-like structural members  248  may be operative to reinforce the resilient layer  152  and increase the modal frequencies of the club head  100  at impact such that the natural frequency is greater than about 3,500 Hz at impact, and exists without substantial dampening by the polymer. When this surface reinforcement is combined with the desirable metallic-like acoustic impact properties of polymers such as PPS or PEEK, a user may find the club head  100  to be audibly similar from an all-metal club head while the design provides significantly improved mass properties (CG location and/or moments of inertia). 
     d. Assembly 
       FIG.  15    illustrates an embodiment of a method  300  for manufacturing a golf club head  100  having the integrally bonded resilient layer  152 , structural layer  156 , and metallic weight pad  220  of the sole member  208 . The method  300  involves thermoforming a fiber reinforced thermoplastic composite into an external shell portion of the club head  100  at step  310 . The thermoforming process may involve, for example, pre-heating a thermoplastic prepreg to a molding temperature at least above the glass transition temperature of the thermoplastic polymer, molding the prepreg into the shape of the shell portion, and then trimming the molded part to size. 
     Once the composite shell portion is in a proper shape, a filled polymeric supporting structure may then be injection molded into direct contact with the shell at step  320 . Such a process is generally referred to as insert-molding. In this process, the shell is directly placed within a heated mold having a gated cavity exposed to a portion of the shell. Molten polymer is forcibly injected into the cavity, and thereafter either directly mixes with molten polymer of the heated composite shell, or locally bonds with the softened shell. As the mold is cooled, the polymer of the composite shell and supporting structure harden together in a fused relationship. The bonding is enhanced if the polymer of the shell portion and the polymer of the supporting structure are compatible and is even further enhanced if the two components include a common thermoplastic resin component. While insert-molding is a preferred technique for forming the structure, other molding techniques, such as compression molding, may also be used. 
     With continued reference to  FIG.  15   , once the sole member  208  is formed through steps  310  and  320 , an FRC crown member  204  may be bonded to the sole member  208  to substantially complete the structure of the rear body  108  (step  330 ). In a preferred embodiment, the crown member  204  may be formed from a thermoplastic FRC material that is formed into shape using a similar thermoforming technique as described with respect to step  310 . Forming the crown member  204  from a thermoplastic composite allows the crown member  204  to be bonded to the sole member  208  using a localized welding technique. Such welding techniques may include, for example, laser welding, ultrasonic welding, or potentially electrical resistance welding if the polymers are electrically conductive. If the crown member  204  is instead formed using a thermoset polymer, then the crown member  204  may be bonded to the sole member  208  using, for example, an adhesive or a mechanical affixment technique (studs, screws, posts, mechanical interference engagement, etc). 
     The rear body  108 , comprising the affixed crown member  204  and sole member  208  may subsequently be adhesively bonded to the metallic front body  104  at step  340 . While adhesives readily bond to most metals, the process of adhering to the polymer may require the use of one or more adhesion promoters or surface treatments to enhance bonding between the adhesive and the polymer of the rear body  108 . 
     III. Benefits 
     Utilizing a mixed material rear body construction can provide a significant reduction in structural weight while not sacrificing any design flexibility and providing a robust means for reintroducing discretionary mass. While such a design may be formed entirely from a filled thermoplastic, such as polyphenylene sulfide (PPS), as discussed above, the use of a fiber reinforced composite provides a stronger and lighter construction across continuous outer surfaces. Conversely, an all-FRC design would not readily incorporate weight-receiving structures, and thus would not be able to easily capitalize on increased discretionary mass. 
     The metallic weight pad is beneficial over a mixed material golf club head devoid a metallic weight pad because the metallic weight pad allows for variance and interchangeability of the metallic weight, while providing a durable and secure location to affix the metallic weight. In comparison to a golf club head devoid of the metallic weight pad, the metallic weight pad securely withstands the torque imparted on the weight pad when a weight is being affixed. Further, the metallic weight pad allows for the manufacturer to interchange the metallic weight, to adjust for manufacturing tolerances (i.e., change the desired swing weight of the overall club head from 206 grams to 209 grams), or adjust for customer specification (i.e., a golfer wants his/her club head heavier, 206 grams to 209 grams). 
     Replacement of one or more claimed elements constitutes reconstruction and not repair. Additionally, benefits, other advantages, and solutions to problems have been described with regard to specific embodiments. The benefits, advantages, solutions to problems, and any element or elements that may cause any benefit, advantage, or solution to occur or become more pronounced, however, are not to be construed as critical, required, or essential features or elements of any or all of the claims. 
     As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated or modified by golf standard organizations and/or governing bodies such as the United States Golf Association (USGA), the Royal and Ancient Golf Club of St. Andrews (R&amp;A), etc.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Accordingly, golf equipment related to the apparatus, methods, and articles of manufacture described herein may be advertised, offered for sale, and/or sold as conforming or non-conforming golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this regard. 
     The above examples may be described in connection with a wood-type golf club, the apparatus, methods, and articles of manufacture described herein. Alternatively, the apparatus, methods, and articles of manufacture described herein may be applicable other type of sports equipment such as a hockey stick, a tennis racket, a fishing pole, a ski pole, etc. 
     Moreover, embodiments and limitations disclosed herein are not dedicated to the public under the doctrine of dedication if the embodiments and/or limitations: (1) are not expressly claimed in the claims; and (2) are or are potentially equivalents of express elements and/or limitations in the claims under the doctrine of equivalents. 
     Various features and advantages of the disclosure are set forth in the following clauses: 
     Clause 1: A golf club head comprising: a metallic front body including a strike face and a surrounding frame that extends rearward from a perimeter of the strike face; wherein the strike face has a centerpoint, a loft plane tangent to the centerpoint along the strike face, and a midplane extending through the centerpoint from the heel to the toe and perpendicular to the loft plane; a rear body coupled to the metallic front body, wherein the rear body and front body form a substantially hollow structure with a cavity therebetween; the rear body comprises a crown member and a sole member, wherein the sole member is coupled to the crown member, wherein the sole member comprises: a structural layer formed from a filled thermoplastic material, the structural layer including a plurality of apertures extending through a thickness of the structural layer; and a resilient layer bonded to an external surface of the structural layer such that the resilient layer extends across each of the plurality of apertures, wherein the resilient layer is formed from a fiber-reinforced thermoplastic composite material and defines an opening; a metallic weight pad extending at least partially through the opening in the resilient layer and bonded to the structural layer, wherein the metallic weight pad comprises an aperture for the attachment of a metallic weight; and wherein the structural layer and the resilient layer each comprise a common thermoplastic resin component, and wherein the structural layer is directly bonded to the resilient layer without an intermediate adhesive. 
     Clause 2: The golf club head of clause 1, wherein the metallic front body further includes a flange that is inwardly recessed from an external surface of the surrounding frame; wherein the structural layer of the sole member is adhesively bonded to the flange; and wherein the external surface of the resilient layer of the sole member is flush with the external surface of the surrounding frame. 
     Clause 3: The golf club head of clause 2, wherein the metallic front body further includes an extension wall that couples the surrounding frame to the flange; wherein the structural layer of the sole member includes a structural member extending towards the metallic front body from the weighted pad; wherein the structural member is operative to transfer a dynamic load between the weight pad and the extension wall during an impact between the strike face and a golf ball. 
     Clause 4: The golf club head of any of clauses 1-3, comprises a head center of gravity located at a head CG depth from the loft plane, measured in a direction perpendicular to the loft plane, and at a head CG height from the midplane, measured in a direction perpendicular to the midplane; wherein the head CG depth is greater than 1.7 inches. 
     Clause 5: The golf club head of any of clauses 1-4, wherein the metallic front body further comprises a strike face insert and a receiving frame; wherein the receiving frame has a greater density than the strike face insert. 
     Clause 6: The golf club head of any of clauses 1-5, wherein the mass of the front body does not exceed 140 g and the total mass of the golf club head does not exceed 210 g. 
     Clause 7: The golf club head of any of clauses 1-6, wherein a mechanical fastener affixes the metallic weight within the aperture of the metallic weight pad; wherein the aperture of the metallic weight pad of the structural layer comprises threading, and the metallic weight is devoid of threading. 
     Clause 8: The golf club head of any of clauses 1-7, wherein the metallic weight has a mass ranging from 5 grams to 30 grams. 
     Clause 9: A golf club head comprising: a metallic front body including a strike face and a surrounding frame that extends rearward from a perimeter of the strike face; wherein the strike face has a centerpoint, a loft plane tangent to the centerpoint along the strike face, and a midplane extending through the centerpoint from the heel to the toe and perpendicular to the loft plane; a rear body coupled to the metallic front body, wherein the rear body and front body form a substantially hollow structure with a cavity therebetween, the rear body comprises a crown member and a sole member, wherein the sole member coupled to the crown member, wherein the sole member comprises: a structural layer formed from a filled thermoplastic material and bonded to the crown member, the structural layer including a plurality of apertures extending through a thickness of the structural layer; and a resilient layer bonded to an external surface of the structural layer without an intermediate adhesive such that the resilient layer abuts the metallic front body and extends across each of the plurality of apertures; wherein the structural layer is formed from a first material consisting of a first plurality of fibers disposed within a first thermoplastic polymer, and the resilient layer is formed from a second material consisting of a second plurality of fibers disposed within a second thermoplastic polymer, wherein an amount of the first thermoplastic polymer, by volume, within the first material is greater than an amount of the second thermoplastic polymer, by volume, within the second material; wherein the structural layer and the resilient layer each comprise a common thermoplastic resin component, and wherein the structural layer is directly bonded to the resilient layer without an intermediate adhesive; and wherein the structural layer of the sole member includes a metallic weight pad, wherein the metallic weight pad comprises an aperture for the attachment of a metallic weight. 
     Clause 10: The golf club head of clause 9, wherein the metallic front body further includes a flange that is inwardly recessed from an external surface of the surrounding frame; wherein the structural layer of the sole member is adhesively bonded to the flange; and wherein the external surface of the resilient layer of the sole member is flush with the external surface of the surrounding frame. 
     Clause 11: The golf club head of any of clauses 9-10, wherein the metallic front body further includes an extension wall that couples the surrounding frame to the bonding flange; wherein the structural layer of the sole member includes a structural member extending towards the metallic front body from the weighted pad; wherein the structural member is operative to transfer a dynamic load between the weight pad and the extension wall during an impact between the strike face and a golf ball. 
     Clause 12: The golf club head of any of clauses 9-11, wherein the first thermoplastic polymer is directly bonded to the second thermoplastic polymer. 
     Clause 13: The golf club head of any of clauses 9-12, wherein the first plurality of fibers comprises a plurality of discontinuous fibers, each having a maximum dimension of less than 0.43 inches. 
     Clause 14: The golf club head of any of clauses 9-13, wherein the second plurality of fibers comprises a plurality of continuous fibers interwoven as a fabric. 
     Clause 15: The golf club head of any of clauses 9-14, wherein the first thermoplastic polymer is the same as the second thermoplastic polymer. 
     Clause 16: The golf club head of any of clauses 9-15, wherein the mass of the front body does not exceed 140 g and the total mass of the golf club head does not exceed 210 g. 
     Clause 17: The golf club head of any of clauses 9-16, comprises a head center of gravity located at a head CG depth from the loft plane, measured in a direction perpendicular to the loft plane, and at a head CG height from the midplane, measured in a direction perpendicular to the midplane; wherein the head CG depth is greater than 1.7 inches. 
     Clause 18: The golf club head of any of clauses 9-17, wherein the metallic front body further comprises a strike face insert and a receiving frame; wherein the receiving frame has a greater density than the strike face insert. 
     Clause 19: The golf club head of any of clauses 9-18, wherein a mechanical fastener affixes the metallic weight within the aperture of the metallic weight pad; wherein the aperture of the metallic weight pad of the structural layer comprises threading, and the metallic weight is devoid of threading. 
     Clause 20: The golf club head of any of clauses 9-19, wherein the metallic weight has a mass ranging from 5 grams to 30 grams.