GOLF CLUB HEADS HAVING PLIANT VIBRATIONAL MITIGATION

Abstract

Embodiments of a damping mechanism comprising a pliant spring mounted on the interior of a hollow golf club having one end affixed to a first club head interior surface location and a moveable end non-affixedly in contact with another club head interior surface location.

Description

FIELD OF INVENTION

This invention generally relates to golf equipment, and more particularly, to wood-type golf club heads.

BACKGROUND

Because thinner and stiffer materials are being used in golf club construction, unwanted vibrations may occur across the golf club head. Area specific vibrational damping on interior surfaces of hollow golf club heads can be applied to damp the unwanted vibrations. Hollow golf club heads may have areas with inconsistent or unwanted vibrational responses to impacting a golf ball. One area of a golf club head may have high amplitude vibrations in an area, creating a sound that is unpleasant to the user. In another case, the golf club strike face may have inconsistent vibrational responses, when a consistent vibrational response across the golf club strike face is more desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top-front perspective view of a wood-type club head.

FIG. 2 illustrates a bottom perspective view of the wood-type club head of FIG. 1.

FIG. 3 illustrates a rear perspective view of the wood-type club head of FIG. 1.

FIG. 4 illustrates a side view of a pliant spring.

FIG. 5 illustrates a pliant spring having two free ends with a single fixed end.

FIG. 6 illustrates a pliant spring with apertures.

FIG. 7 illustrates a free end with a contact pad.

FIG. 8 illustrates a free end with contact pad from two perspectives.

FIG. 9 illustrates a pliant spring placed within a hollow body golf club head.

FIG. 10 illustrates pliant springs configured to contact the strike face interior surface.

FIG. 11 illustrates a hollow, conical contact pad.

FIG. 12 illustrates a press fit contact pad.

FIG. 13 illustrates a pliant spring mechanically attached to a golf club head interior surface.

FIG. 14 illustrates a CT test coupon configuration.

FIG. 15 illustrates CT test coupon results.

DEFINITIONS

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.

The term characteristic time “CT” is used herein to mean a measurement used to determine the amount of time, measured in microseconds (us), that a golf ball contacts the strike face at the moment of impact. The characteristic time is measured by impacting a specific spot on the striking surface several times with a ball-shaped weight of a small steel pendulum. The characteristic time measurement is for wood-type club heads such as drivers, fairway woods, or hybrids. A computer program measures the amount of time the ball shaped weight contacts the strike face at the moment of impact. CT values were based on the method outlined in the USGA's Procedure for Measuring the Flexibility of a Golf Clubhead. For example, Section 2 of the USGA's Procedure for Measuring the Flexibility of a Golf Clubhead (USGA-TPX3004, Rev. 2.0, Apr. 9, 2019) (the “Protocol For Measuring The Flexibility of A Golf Club Head”).

As defined herein, “spline method” refers to a method to determine the location where the curvature of a surface changes. For example, the spline method can be used to determine where the surface curvature deviates from a club head striking surface bulge and roll curvature. The spline method can be implemented by imposing a spline onto the curved surface with an interval such that the spline indicates where a significant change in curvature begins.

The terms “loft” or “loft angle” of a golf club, as described herein, refers to the angle formed between the strike face and the shaft, as measured by any suitable loft and lie machine.

“Driver golf club heads” as used herein comprise a loft angle 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 many embodiments, “driver golf club heads” as used herein comprises a volume greater than approximately 400 cc, greater than approximately 425 cc, greater than approximately 445 cc, greater than approximately 450 cc, greater than approximately 455 cc, greater than approximately 460 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 driver volume 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.

“Fairway wood golf club heads” as used herein comprise a loft angle 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 some embodiments, the fairway wood club head loft angle 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 other embodiments, the fairway wood loft angle 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.

Further, “fairway wood golf club heads” as used herein comprises a volume 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 some embodiments, the fairway wood volume 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 250-350 cc, or approximately 275-375 cc.

“Hybrid golf club heads” as used herein comprise a loft angle 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 many embodiments, the hybrid loft angle 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.

Further, “hybrid golf club heads” as used herein comprise a volume 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 hybrid volume can be approximately 100 cc-150 cc, approximately 75 cc-150 cc, approximately 100 cc-125 cc, or approximately 75 cc-125 cc.

The golf club heads described in this disclosure can be formed from a metal, a metal alloy, a composite, or a combination of metals and composites. For example, the golf club head can be formed from, but not limited to, steel, steel alloys, stainless steel alloys, nickel, nickel alloys, cobalt, cobalt alloys, titanium alloys, an amorphous metal alloy, or other similar materials. For further example, the golf club head can be formed from, but not limited to, C300 steel, C350 steel, 17-4 stainless steel, or T9s+ titanium.

The term “geometric centerpoint,” as used herein, can refer to a strike face perimeter geometric centerpoint, and at a strike face height midpoint. In the same or other examples, the geometric centerpoint also can be centered with respect to an engineered impact zone, which can be defined by a region of grooves on the strike face. As another approach, the geometric centerpoint strike face can be located in accordance with the definition of a golf governing body such as the United States Golf Association (USGA).

The term “ground plane,” as used herein, can refer to a reference plane associated with the surface on which a golf ball is placed. The ground plane can be a horizontal plane tangent to the sole at an address position.

The term “face height,” as used herein, can refer to a distance measured parallel to loft plane between a strikeface perimeter top end and a strikeface perimeter bottom end.

The term “lie angle,” as used herein, can refer to an angle between a hosel axis, extending through the hosel, and the ground plane. The lie angle is measured from a front view.

The “loft plane” of the driver-type golf club head, as used herein, is a plane that is tangent to the strike face geometric center. The loft plane forms a loft angle with the ground plane.

The term “loft angle,” as used herein, can refer to an angle measured between the loft plane and the XY plane.

The “depth” of the driver-type golf club head as used herein can be defined as a front-to-rear dimension of the driver-type golf club head.

The “height” of the driver-type golf club head as used herein can be defined as a crown-to-sole dimension of the driver-type club head. In many embodiments, the height of the club head can be measured according to a golf governing body such as the United States Golf Association (USGA).

The “length” of the driver-type golf club head as used herein can be defined as a heel-to-toe dimension of the driver-type club head. In many embodiments, the length of the club head 100 can be measured according to a golf governing body such as the United States Golf Association (USGA).

The “face height” of the driver-type golf club head, as used herein, can be defined as a height measured parallel to loft plane between a top end of the strike face perimeter near the crown and a bottom end of the strike face perimeter near the sole. In these embodiments, the strike face perimeter can be located along the strike face outer edge, where the curvature deviates from the bulge and/or roll of the strike face.

The “geometric center” of the driver-type golf club head, as used herein, is the geometric center point of a strike face perimeter. As another approach, the strike face geometric center can be located in accordance with the definition of a golf governing body such as the United States Golf Association (USGA).

The “geometric center height” of the driver-type golf club head, as used herein, is a height measured perpendicular from the ground plane to the geometric center of the driver-type club head.

The “leading edge” of the driver-type golf club head as used herein can be identified as the most sole-ward portion of the strike face perimeter. For example, a driver-type golf club head leading edge is the transition from the strike face roll and bulge to the sole of the driver-type golf club head.

An “XYZ” coordinate system of the golf club head, as used herein, is based upon the strike face geometric center. The golf club head dimensions as used herein can be measured based on a coordinate system as defined below. The strike face geometric center defines a coordinate system having an origin located at the strike face geometric center. The coordinate system defines an X axis, a Y axis, and a Z axis. The X axis extends through the strike face geometric center in a direction from the heel to the toe of the fairway-type club head. The Y axis extends through the strike face geometric center in a direction from the crown to the sole of golf club head. The Y axis is perpendicular to the X axis. The Z axis extends through the strike face geometric center in a direction from the front end to the rear end of the golf club head. The Z axis is perpendicular to both the X axis and the Y axis.

The term or phrase “center of gravity position” or “CG location” as used herein, is the location of the club head center of gravity (CG) with respect to the secondary coordinate system, wherein the CG position is characterized by locations along the X′-axis, the Y′-axis, and the Z′-axis. The term “CGx” can refer to the CG location along the X′-axis, measured from the origin point. The term “CG height” can refer to the CG location along the Y′-axis, measured from the origin point. The term “CGy” can be synonymous with the CG height. The term “CG depth” can refer to the CG location along the Z′-axis, measured from the origin point. The term “CGz” can be synonymous with the CG depth.

The term or phrase “moment of inertia” (hereafter “MOI”) as used herein, are the values measured about the CG. The term “Ixx” as used herein, is the MOI measured in the heel-to-toe direction, parallel to the X-axis. The term “Iyy” as used herein, is the MOI measured in the sole-to-crown direction, parallel to the Y-axis. The term “Izz” as used herein, is the MOI measured in the front-to-back direction, parallel to the Z-axis. The MOI values MOIxx, MOIyy, and MOIzz determine how forgiving the club head is for off-center impacts with a golf ball. A high moment of inertia Ixx and a high moment of inertia Iyy provide the club head improved feel, forgiveness, and playability.

The term or phrase “spring”, as used herein, is an object that returns to its original shape after being compressed or stretched.

Described herein are various embodiments of wood-type golf club heads (e.g. drivers, fairway woods, or hybrids, also referred to as “the club head”) comprising one or more pliant springs in contact with an interior surface to adjust the vibrational response to a ball impact across the wood-type golf club head. The club head comprises a strike face secured to a body to define an interior cavity. The strike face can be formed from a metal material or a composite material, and the body can be formed from a metal or composite material. The composite portion can form all or a portion of the crown, the sole, or both the crown and the sole. The club head can be an all-metal construction or multi-material construction.

Other features and aspects will become apparent by consideration of the following detailed description and accompanying drawings. Before any embodiments of the disclosure are explained in detail, it should be understood that the disclosure is not limited in its application to the details or embodiment and the arrangement of components as set forth in the following description or as illustrated in the drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways. It should be understood that the description of specific embodiments is not intended to limit the disclosure from covering all modifications, equivalents and alternatives falling within the spirit and scope of the disclosure. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

Described herein are golf club heads having pliant springs used to modify club head surface vibrations resulting from impact. Pliant springs are positioned to contact a club head surface and configured to move in response to the movement of that surface, while also damping vibrations at the contacted surface. The damping action of the pliant spring reduces the amplitude of the vibrations and decreases the extinction time of the vibrations at the contacted location or locations. This reduction of amplitude and decrease of vibrational extinction time diminishes the unwanted effects of vibrations at the contact location. A pliant spring is not a brace, stop, or rib. The pliant spring does not directly transfer any significant stress or force from the surface to another golf club head portion. The pliant spring does not limit the extent to which the surface deflects. Instead, during impact with a golf ball, the one or more pliant springs dampen or reduce the duration and amplitude of the club head wall vibrations. In some examples described herein, the pliant springs dampen vibrations from the strike face. One or more pliant springs may be configured to have one end in contact with a strike face interior surface. Prior to impact, the one or more pliant springs are in an initial, undeflected state, and may be used to place a relatively small preload against the strike face interior surface. The pliant springs deflect at impact to maintain contact as the golf club head but upon this impact, the following post-impact oscillations are absorbed by the pliant spring, diminishing the oscillation amplitude and duration. Pliant springs can be placed in contact with interior surfaces away from the strike face and have the effect. One or more pliant springs may be configured to contact and alter the vibrational response of other club head areas, such as the sole, crown, or sidewalls.

II. GENERAL DESCRIPTION OF A GOLF CLUB HEAD

A golf club head 100 according to the present disclosure can comprise a strike face 102, and a club head body 103 as best shown in FIGS. 1-3. More specifically, the club head body 103 can comprise a first body member 110 and optionally a second body member 112. Alternately, the club head body 103 can comprise a plurality of members. The strike face 102 and the club head body 103 are joined to define a substantially closed/hollow interior cavity 113. The club head 100 comprises a crown 108, a sole 114 opposite the crown 108, a heel 104, a toe 106 opposite the heel 104, a front 105, and a rear 107 opposite the front 105. The club head body 103 can further include a skirt or trailing edge 109 located between and adjoining the crown 108 and the sole 114. The skirt 109 extends from near the heel 104 to near the toe 106. In some embodiments, the club head 100 is a wood-type club head such as a driver, fairway wood, or hybrid as described in this disclosure.

The club head body 103 can extend over the crown 108, the sole 114, the heel 104, the toc 106, the rear 107, and a front perimeter 105. In these embodiments, the club head body 103 defines a front aperture 128 in the club head front 105 and the strike face 102 is positioned within the front aperture 128 to form the club head 100. In other embodiments, strike face 102 extends over the perimeter of the front 105 and can include a strike face return portion 126 extending rearward from the strike face 102. The strike face return portion 126 can extend over at least one of the crown 108, the sole 114, the heel 104, and the toe 106. In embodiments comprising the return portion 126, the strike face return portion 126 is secured to the club head body 103 to form the club head 100. In these embodiments, the club head 100 can resemble a cup face or face wrap design.

The crown 108, skirt 109, sole 114, and or strike face 102 can be partially or entirely made from a composite material. A composite material can be adhered to any of the crown 108, skirt 109, sole 114, and or strike face 102. of the club head 100. Lap joints may be used to facilitate joining composite material to the club head body 103, sole 114, strike face return portion 126, or strike face 102.

The club head 100 comprises a hosel 120 for attaching the club head 100 to a shaft. As best shown in FIG. 1 the hosel 120 can receive a hosel sleeve 122. The hosel sleeve 122 can be coupled with the hosel structure 120 in a plurality of configurations, thereby permitting the golf shaft to be secured to the hosel structure 120 at any one of a plurality of angles.

The club head 100 can comprise a weight port 116 configured to receive a removable weight 118. In many embodiments, the weight port 116 can be located in the sole 114 and/or in the skirt 109. Club head 100 also can comprise a mass pad 130 or weight pad (hereafter “mass pad 130”). In many embodiments, the mass pad 130 can be located on the interior surface 115. In other embodiments, the mass pad 130 can be located on the sole 114 and skirt 109, and within the interior cavity 113. In other embodiments still, the club head 100 can comprise one or more weight ports 116, and one or more mass pads 130. The removable weight 118 and mass pad 130 can adjust the moment of inertia (MOI) properties and center of gravity (CG) location.

The strike face 102 comprises a striking surface 125 configured to impact a golf ball, and a strike face interior surface 124 opposite the striking surface 125. Strike face 102 defines a thickness measured between the striking surface 125 and the strike face interior surface 124. The strike face 102 can comprise a variable thickness profile. The striking surface 125 further defines a strike face geometric center 150. The strike face geometric center 150 can be located in accordance with the definition of a golf governing body such as the United States Golf Association (USGA).

The strike face perimeter 127 can be located along an outer edge of the striking surface 125, where the striking surface 125 curvature deviates from the bulge and roll curvature. The striking surface 125 comprises a striking surface area measured within the boundary of the strike face perimeter 127. In one approach, the spline method, as described above, can be used to determine the outer edge location where the curvature deviates from the striking surface bulge and roll. In many embodiments, the center of gravity 151 is strategically positioned toward the sole 114 and the club head rear 107, to improv feel and playability.

III. PLIANT SPRING

One or more pliant springs 200 may be attached to the interior surface 115 to alter the vibration response of the golf club head 100 after impact with a golf ball. Each pliant spring 200 has at least one free end 202 and one fixed end 204. The fixed end 204 of each pliant spring 200 may be permanently joined or affixed to an attachment location 206 on the interior surface 115. The pliant spring 200 may be mechanically affixed to an attachment location 206, allowing the pliant spring 200 to be removable. While the free end 202 contacts at least one other interior surface contact location 208, it is not joined or affixed to the club head interior surface 115. Contact location 208 is spaced from attachment location 206. More than one pliant spring 200 may be provided. Each of the one or more pliant springs 200 may have a plurality of free ends 202 engaging different contact locations 208, and/or a plurality of fixed ends 204 coupled to different attachment locations 206. In some embodiments, the golf club head 100 can comprise one or more pliant springs 200 that extend from a strike face interior perimeter 125 surrounding the strike face 102 to contact the strike face interior surface 124.

The one or more pliant springs 200 can alter the vibrational characteristics of the club head areas contacted by the free ends 202. For example, certain strike face areas may have a relatively higher CT than the rest of the strike face 102. The pliant spring 200 can reduce the CT at these “hot spots” by putting the pliant spring 200 in contact with the “hot spots.” Having the flexibility to damp oscillations very selectively provides more design flexibility. For example, decreased CT measurement allows other performance-enhancing features to be incorporated into the club head while keeping the strike face CT within the USGA limits. One example of a performance-enhancing feature is a thinner face, which increases face flexure during high-energy impacts with a golf ball. While the thinner face could increase CT, adding one or more pliant springs 200 can reduce CT in discrete locations so that the club conforms to USGA requirements, while retaining increased ball speed provided by the thin face.

Spring Structure

Referring to FIGS. 4, 5, and 7, each pliant spring 200 comprises a spring body 201 having at least one fixed end 204 and at least one free end 202. Each pliant spring body 201 may comprise a plurality of fixed ends 204 and/or a plurality of free ends 202. For instance, the spring body 201 may be Y-shaped or X-shaped. A Y-shaped spring body 201 may have a plurality of fixed ends 204 or a plurality of free ends 202. Each free end 202 further comprises at least one contact pad 210. The pliant spring 200 may comprise a plurality of contact pads 210 when it comprises a plurality of free ends 202. The spring body 201 further comprises a spring length 212, a spring width 213, a spring thickness 214, a spring top side 215, and a spring bottom side 216 opposite the spring top side 215. The spring length 212 is measured longitudinally from the spring body 201 fixed end 204 to the free end 202 along the spring body 201 inclusive of any bends or curves in the spring body 201. The spring length 212 is in a range of 0.1 inch to 2.5 inches. The spring length 212 may be 0.1 inch, 0.2 inch, 0.3 inch, 0.4 inch, 0.5 inch, 0.6 inch, 0.7 inch, 0.8 inch, 0.9 inch, 1.0 inch, 1.1 inches, 1.2 inches, 1.3 inches, 1.4 inches, 1.5 inches, 1.6 inches, 1.7 inches, 1.8 inches, 1.9 inches, 2.0 inches, 2.1 inches, 2.2 inches, 2.3 inches, 2.4 inches, or 2.5 inches. Spring width 213 is measured perpendicularly across the spring body length 212 at any point along the spring body 201. The spring width is in a range of 0.1 inch to 1.0 inch. The spring width 213 may be 0.1 inch, 0.2 inch, 0.3 inch, 0.4 inch, 0.5 inch, 0.6 inch, 0.7 inch, 0.8 inch, 0.9 inch, or 1.0 inch. The spring thickness 214 is measured perpendicularly at any point on the spring body 201 from the spring top side 215 to the spring bottom side 216. The spring thickness 214 is in the range of 0.05 inch to 0.25 inch. Spring thickness 214 may be 0.05 inch, 0.10 inch, 0.15 inch, 0.20 inch, or 0.25 inch. The spring width 213 and spring thickness 214 may vary across the spring length 212. The spring body 201 may further comprise a pre-set spring bend shape.

The pliant spring 200 may have an adjustable effective length. The pliant spring 200 may provide multiple attachment locations 206 along the spring length 212, each of which may be used as the fixed end 204. Further, the pliant spring 200 may provide more than one contact pad attachment location to house a contact pad 210 on each spring arm. Provision of such attachment locations 206 and contact pad attachment locations allow a single pliant spring 200 component to be adjusted to different effective lengths. This has the advantage of providing flexibility of placement within the golf club head.

Together, the spring width 213 and spring thickness 214 comprise a spring cross-sectional shape at any point along the spring length 212. A cross-section is defined in a plane normal to the spring top side 215 and spring bottom side 216 at any point along the spring length 212. The spring cross-sectional shape may be rectangular, a conical section, polyhedral, or any combination thereof. The spring cross-sectional shape further comprises a cross-section area. Referring to FIG. 8, spring body 201 may further comprise reduced thickness areas, cut-outs, or apertures along the spring length 212. If the pliant spring fixed end 204 is attached mechanically to an attachment location 206, the mechanical attachment can provide multiple orientation options for the attachment of the pliant spring 200. The spring body 201 cross-sectional area may be in a range of 0.01 inches2 to 0.5 inches². The spring body cross-sectional area may be 0.01 inches², 0.02 inches², 0.03 inches², 0.04 inches², 0.05 inches², 0.10 inches², 0.15 inches², 0.20 inches², 0.25 inches², 0.30 inches², 0.35 inches², 0.40 inches², 0.45 inches², or 0.50 inches².

Each fixed end 204 of the spring body 201 is configured to attach to the interior surface 115 at an attachment location 206. If attachment location 206 is planar, then the fixed end 204 will conform to the planar shape of the attachment location 206. If the attachment location 206 is a non-planar shape, then the fixed end 204 will be configured to match that non-planar shape to increase surface-to-surface contact. The fixed end 204 comprises a fixed end base area 205 in contact with the interior surface attachment location 206. The fixed end base area 205 may be in a range of 0.25 inches² to 2.0 inches².

Each spring body 201 free end 202 is configured to retain a contact pad 210. Each free end 202 may be flattened and may have grooves or notches to retain the contact pad 210. Each free end 202 may be any flat shape, t-shaped, pointed, cylindrical, conical, spherical, or any geometric solid in shape, and may have grooves, notches, apertures, or end knobs to retain the contact pad 210. The free end 202 may have any shape or configuration to securely retain the contact pad 210. The contact pad 210 may be co-molded with or over-molded onto the free end 202. The contact pad 210 may be adhesively attached to the free end 202. The contact pad 210 may comprise a contact end 225 and a contact pad attachment end 226. The contact pad attachment end 226 may further comprise a contact pad female aperture 227 to fit over the free end 202. The contact pad 210 may comprise a deformable material that can be press fit over the free end 202. The contact pad 210 may attach to the free end 202 with a snap fit connection. The contact pad 210 may be affixed to the free end 202 with a mechanical fastener such as a threaded fastener or rivet.

a. Pre-Set Bending

In some embodiments, the spring body 201 may be straight. That is, an entirety of the spring body 201 is parallel to a single imaginary plane. The spring body 201 may comprise at least one spring bend 218, wherein at least a portion of the spring length 212 is pre-set to a curvilinear shape. The curvilinear shape may be a convex conic section such that a spring bend apex 220 on the spring length 212 curved portion is furthest from the interior surface contact location 208. A spring bend apex distance 221 may be measured perpendicular to the closest interior surface 115 to the spring bend apex 220. The spring bend apex distance 221 defines the maximum distance between the spring body 201 and the adjacent interior surface 115. The curvilinear shape may comprise multiple spring bends 218 in different directions.

When the spring body 201 comprises a plurality of free ends 202, the spring body 201 may also comprise a plurality of spring lengths 212 measured along the spring body between the fixed end 204 and the free ends 202, spring widths 213 measured perpendicular to the spring length 212, spring thicknesses 214 measured between a spring top side 215 and a spring bottom side 216, and spring bends 218. When the spring body 201 comprises a plurality of free ends 202, each free end 202 has a contact pad 210. Further, a plurality of free ends 202 defines at least one contact pad separation distance 222.

The spring body bend 218 is configured such that the free end 202 defines a contact angle 211 between the free end 202 and the contacted interior surface 133. The contact angle 211 is measured between the contact location 208 interior surface 115 and the spring bottom side 216 immediately adjacent the contact pad 210. The contact angle may have a range of 90 degrees to 180 degrees.

b. Attachment Means

The spring body 201 may be attached at the fixed end 204 to an attachment location 206 by welding, brazing, adhesive attachment, snap fitting, or by means of a mechanical fastener. Spring body 201 may be permanently affixed, or fixed end 204 may be removably affixed to the attachment location 206.

c. Spring Placement

The one or more pliant springs 200 may be placed such the fixed end or ends 204 are located adjacent to the strike face perimeter 127. The attachment location 206 may be in any golf club head front portion interior surface 115. The attachment location 206 may be in an interior crown or sole surface, an interior sidewall surface, or a rear interior surface. The contact pad or pads may contact the strike face interior surface 124. Additionally or alternatively, the contact pad or pads 210 may contact the club head interior surface 115 at the sole 114, sidewall, rear 107, front 105, or crown 108.

Referring to FIG. 9, when the pliant spring contact pad 210 engages the strike face interior surface 124, the contact location 208 may be placed outside the area of maximum vibrational amplitude. In such a case, contact location 208 is outside the strike face area wherein the vibrational amplitude is between 30% to 100% of the maximum amplitude.

d. Spring Physical Characteristics

Spring body 201 may comprise a metallic alloy, polymeric material, a resin, or a fiber-reinforced composite. The spring body material may be the same as the club head body material at the attachment area. The spring body material may be different from the club head body material at the attachment area. The spring body material may be a metallic alloy including but not limited to a Ti alloy, a steel alloy, an aluminum alloy, a manganese alloy, or a copper alloy. The spring body material may be a polymer, a fiber-reinforced composite, or a fiber reinforced polymer. The spring body 201 comprises a spring constant “k.” The spring constant may be in a range of 10 lbf/inch to 100 lbf/inch (pound force/inch). The spring body 201 may have a mass of 0.1 grams to 10 grams. The spring body mass may be 0.1 grams, 0.2 grams, 0.3 grams, 0.4 grams, 0.5 grams, 0.6 grams, 0.7 grams, 0.8 grams, 0.9 grams, 1.0 grams, 1.5 grams, 2.0 grams, 2.5 grams, 3.0 grams, 3.5 grams, 4.0 grams, 5.0 grams, 6.0 grams, 7.0 grams, 8.0 grams, 9.0 grams, or 10 grams.

e. Contact Pad

Referring to FIG. 8, contact pad 210 may comprise a polymeric material, a natural rubber, a natural or artificial felt, cork, or resin. The contact pad 210 may have a material density in the range of 0.3 g/cc to 8.0 g/cc. The contact pad 210 may comprise a uniform density or a non-uniform density. The contact pad 210 may comprise a single material or comprise two or more materials. The contact pad 210 may comprise a 3D printed interior lattice having at least one solid exterior surface. The contact pad 210 material may have hardness between Shore A 15 and Shore A 90. The contact pad 210 may be over-molded onto the free end 202. The contact pad 210 may comprise a female opening that may be press-fit over the free end 202. The contact pad 210 may be cuboid, ellipsoid, polyhedral, or any other appropriate shape. Contact pad 210 comprises a maximum pad length 229 measured from contact pad attachment end 226 to the contact end 225, a maximum pad width 231 measured perpendicularly to the maximum pad length 229, and a maximum pad thickness 233 measured perpendicularly to both the maximum pad length 229 and maximum pad width 231. The maximum pad length is in the range of 0.1 inch to 0.5 inch. The maximum pad length may be 0.1 inch, 0.2, 0.3, 0.4, or 0.5 inch. The maximum pad width is in the range of 0.1 inch to 0.5 inch. The maximum pad width may be 0.1 inch, 0.2, 0.3, 0.4, or 0.5 inch. The maximum pad thickness is in the range of 0.1 inch to 0.5 inch. The maximum pad thickness may be 0.1 inch, 0.2, 0.3, 0.4, or 0.5 inch.

When the club head strikes a golf ball, the contact pad may compress. The contact pad 210 further comprises a resting contact area (prior to a ball impact) and a maximum compressed contact area (during the maximum deflection of the contact surface during a ball impact) in the range of 0.1 inch² to 0.5 inch². Contact end 225 may comprise a shape that is solid, such as a solid circle, rectangle, or other solid geometric shape. Contact end 225 may comprise a geometric shape perimeter, such as a circular perimeter having a contact surface defining an outer edge of the contact end 225, having an interior space that is not in contact with the club head interior surface 115. The contact end 225 may comprise an inverted cone, such that the contact end cone perimeter is in resting contact with the club head interior surface 115. The contact pad 210 is compressed during a ball impact, an increased contact end 225 surface area is brought into contact with the club head interior surface 115 as the contact pad 210 compresses.

Spring Functional Effect

Each pliant spring 200 places a preload force on the contacted interior surface 115 in a range of 0.1 ft-lb·s to 20 ft-lbs. Each pliant spring 200 decreases the vibrational amplitude at the club head interior surface contact location 208 in a range of 5% to 50%. Each pliant spring 200 dampens the impact vibrational duration at the club head interior surface contact location 208 in a range of 0.01 seconds to 5.0 seconds. When the pliant spring contact location 208 is located on the interior strike face surface, then the CT of the strike face is lowered to a measurable degree.

IV. EXAMPLES

Example 1

Referring to FIG. 5, in modifying CT values, a 4-6 micro-second reduction in CT is considered significant, as it may be sufficient to reduce CT at “hot spots” (or limited areas of higher CT) to meet the USGA requirements. Referring to FIGS. 5 and 6, a circular test coupon having a thickened perimeter and a thinner, constant-thickness central portion was subjected to a CT test. In the first configuration, the test coupon was unmodified. The CT measurement was 278.3 ms. In the second configuration, a piece of lead tape was attached to the interior surface of the test coupon. The CT measurement was 274.7 ms. While the lead tape lowered the CT compared to the unmodified configuration, the lead tape also added significant mass to the coupon. In a third configuration, two pliant springs 200 were attached to the thickened perimeter, and Shore A 40 contact pads 210 were placed in contact with the coupon interior surface. The CT measurement for the third configuration was 267.0 ms, reflecting a significant reduction as compared to the un-modified coupon. In a fourth configuration, two pliant springs 200 were attached to the thickened perimeter, and Shore A 60 contact pads 210 were placed in contact with the coupon interior surface. The CT measurement for the fourth configuration was 272.0 ms, which also reflects a significant reduction from the un-modified coupon. This example demonstrates the ability of relatively low mass, low cost, pliant springs 200 to modify CT values in a range that is functionally significant.

Clauses

• • Clause 1. A golf club head comprising a hollow golf club head body having an interior surface defining an enclosed interior cavity; a pliant spring, comprising: a fixed end coupled to a first attachment location of the interior surface; a free end opposite the fixed end; a contact pad coupled to the free end and contacting a first contact location of the interior surface; wherein the first contact location is spaced from the first attachment location; and a spring body extending between the fixed end and the free end.
  • Clause 2. The golf club head of clause 1, wherein the spring body comprises a spring length measured longitudinally along the spring body measured between the fixed end and the free end; wherein the spring length is in a range between 0.5 inch and 3.5 inches; wherein the spring body comprises a spring width measured perpendicularly to the spring length; wherein the spring width is in a range between 0.1 inch to 1.0 inch; wherein the spring body comprises a spring thickness measured perpendicularly at any point on the spring body from a spring top side to a spring bottom side.
  • Clause 3. The golf club head of clause 2, wherein the spring width is constant along the spring length and the spring thickness is constant along the spring length.
  • Clause 4. The golf club head of clause 2, wherein the spring width varies along the spring length and the spring thickness varies along the spring length.
  • Clause 5. The golf club head of clause 1, wherein the spring body is straight such that an entirety of the spring length is parallel to a single imaginary plane.
  • Clause 6. The golf club head of clause 1, wherein the spring body further comprises at least one curvilinear spring bend between the fixed end and the moveable end.
  • Clause 7. The golf club head of clause 1, wherein the fixed end is affixed to the attachment location with an attachment method chosen from the group consisting of: welding, braising, adhesive attachment, snap fitting, and a mechanical fastener.
  • Clause 8. The golf club head of clause 7, wherein the fixed end is removably affixed to the attachment location.
  • Clause 9. The golf club head of clause 1, wherein the interior surface attachment location is chosen from a group consisting of: an interior crown surface, an interior sole surface, an interior sidewall surface, and an interior rear surface.
  • Clause 10. The golf club head of clause 1, wherein the interior surface contact location is chosen from a group consisting of: an interior crown surface, an interior sole surface, an interior sidewall surface, and an interior strike face surface.
  • Clause 11. The golf club head of clause 1, wherein in the contact pad is compressible, having a material hardness in a range between Shore A 30 and Shore A 90;
  • wherein the contact pad further comprises a contact material chosen from a group consisting of: a polymeric material, a natural rubber, a natural or artificial felt, cork, and resin.
  • Clause 12. The golf club head of clause 1, wherein the contact pad further comprises a contact end, a contact pad attachment end, a pad maximum length in the range of 0.1 inch to 0.5 inch, a pad maximum width length in the range of 0.1 inch to 0.5 inch, and a pad maximum thickness length in the range of 0.1 inch to 0.5 inch.
  • Clause 13. The golf club head of clause 1, wherein the spring body further comprises a plurality of through apertures along the spring length.
  • Clause 14. The golf club head of clause 1, wherein the spring body comprises a spring body material consisting of a material chosen from a group consisting of: limited to a Ti alloy, a steel alloy, an aluminum alloy, a manganese alloy, a copper alloy, a polymer, a fiber-reinforced composite, and a fiber reinforced polymer.
  • Clause 15. The golf club head of clause 1, wherein the spring body further comprises a spring body mass in the range of 0.1 grams to 20.0 grams.
  • Clause 16. A golf club head comprising a hollow golf club head body having an interior surface defining an enclosed interior cavity; a pliant spring, comprising: a single fixed end attached to an interior surface attachment location; multiple free ends each with one of multiple contact pads in contact with, but not attached to multiple contact locations other than the interior surface attachment location; and a spring body between the fixed end and the free ends; wherein the spring body further comprises multiple legs between the fixed end and the multiple free ends.
  • Clause 17. The golf club head of clause 16, wherein the spring body multiple legs each comprise a spring length measured longitudinally along the spring body measured between the fixed end and the free end; wherein the spring length is in a range between 0.5 inch and 3.5 inches; wherein the spring body multiple legs each comprise a spring width measured perpendicularly to the spring length; wherein the spring width is in a range between 0.1 inch to 1.0 inch; wherein the spring body multiple legs each comprise a spring thickness measured perpendicularly at any point on the spring body from a spring top side to a spring bottom side.
  • Clause 18. The golf club head of clause 16, wherein the interior surface attachment location is chosen from a group consisting of: an interior crown surface, an interior sole surface, an interior sidewall surface, and an interior rear surface.
  • Clause 19. The golf club head of clause 16, wherein the spring body comprising multiple legs consists of two legs having two moveable ends forming a y-shaped spring body having two contact pads having two contact locations.
  • Clause 20. The golf club head of clause 19, wherein each of the two contact pads are formed from a polymeric material over-molded onto one of the two moveable ends.
  • Clause 21. The golf club head of clause 19, wherein the two contact pads define a contact pad separation distance measured along the club head interior surface separating the two contact locations.

Claims

1. A golf club head comprising: a hollow golf club head body having an interior surface defining an enclosed interior cavity;a pliant spring, comprising:a fixed end coupled to a first attachment location of the interior surface;a free end opposite the fixed end;a contact pad coupled to the free end and contacting a first contact location of the interior surface;wherein the first contact location is spaced from the first attachment location; anda spring body extending between the fixed end and the free end.

2. The golf club head of claim 1, wherein the spring body comprises a spring length measured longitudinally along the spring body measured between the fixed end and the free end; wherein the spring length is in a range between 0.5 inch and 3.5 inches;wherein the spring body comprises a spring width measured perpendicularly to the spring length;wherein the spring width is in a range between 0.1 inch to 1.0 inch;wherein the spring body comprises a spring thickness measured perpendicularly at any point on the spring body from a spring top side to a spring bottom side.

3. The golf club head of claim 2, wherein the spring width is constant along the spring length and the spring thickness is constant along the spring length.

4. The golf club head of claim 2, wherein the spring width varies along the spring length and the spring thickness varies along the spring length.

5. The golf club head of claim 1, wherein the spring body is straight such that an entirety of a spring length is parallel to a single imaginary plane.

6. The golf club head of claim 1, wherein the spring body further comprises at least one curvilinear spring bend between the fixed end and the moveable end.

7. The golf club head of claim 1, wherein the fixed end is affixed to the attachment location with an attachment method chosen from the group consisting of: welding, braising, adhesive attachment, snap fitting, and a mechanical fastener.

8. The golf club head of claim 7, wherein the fixed end is removably affixed to the attachment location.

9. The golf club head of claim 1, wherein the interior surface attachment location is chosen from a group consisting of: an interior crown surface, an interior sole surface, an interior sidewall surface, and an interior rear surface.

10. The golf club head of claim 1, wherein the interior surface contact location is chosen from a group consisting of: an interior crown surface, an interior sole surface, an interior sidewall surface, and an interior strike face surface.

11. The golf club head of claim 1, wherein in the contact pad is compressible, having a material hardness in a range between Shore A 30 and Shore A 90; wherein the contact pad further comprises a contact material chosen from a group consisting of: a polymeric material, a natural rubber, a natural or artificial felt, cork, and resin.

12. The golf club head of claim 1, wherein the contact pad further comprises a contact end, a contact pad attachment end, a pad maximum length in the range of 0.1 inch to 0.5 inch, a pad maximum width length in the range of 0.1 inch to 0.5 inch, and a pad maximum thickness length in the range of 0.1 inch to 0.5 inch.

13. The golf club head of claim 1, wherein the spring body further comprises a plurality of through apertures along the spring length.

14. The golf club head of claim 1, wherein the spring body comprises a spring body material consisting of a material chosen from a group consisting of: limited to a Ti alloy, a steel alloy, an aluminum alloy, a manganese alloy, a copper alloy, a polymer, a fiber-reinforced composite, and a fiber reinforced polymer.

15. The golf club head of claim 1, wherein the spring body further comprises a spring body mass in the range of 0.1 grams to 20.0 grams.

16. A golf club head comprising: a hollow golf club head body having an interior surface defining an enclosed interior cavity;a pliant spring, comprising: a single fixed end attached to an interior surface attachment location;multiple free ends each with one of multiple contact pads in contact with, but not attached to multiple contact locations other than the interior surface attachment location; and a spring body between the fixed end and the free ends;wherein the spring body further comprises multiple legs between the fixed end and the multiple free ends.

17. The golf club head of claim 16, wherein the spring body multiple legs each comprise a spring length measured longitudinally along the spring body measured between the fixed end and the free end; wherein the spring length is in a range between 0.5 inch and 3.5 inches;wherein the spring body multiple legs each comprise a spring width measured perpendicularly to the spring length;wherein the spring width is in a range between 0.1 inch to 1.0 inch;wherein the spring body multiple legs each comprise a spring thickness measured perpendicularly at any point on the spring body from a spring top side to a spring bottom side.

18. The golf club head of claim 16, wherein the interior surface attachment location is chosen from a group consisting of: an interior crown surface, an interior sole surface, an interior sidewall surface, and an interior rear surface.

19. The golf club head of claim 16, wherein the spring body comprising multiple legs consists of two legs having two moveable ends forming a y-shaped spring body having two contact pads having two contact locations.

20. The golf club head of claim 19, wherein each of the two contact pads are formed from a polymeric material over-molded onto one of the two moveable ends.