Optimally elastic golf club head

Abstract

A golf club head is composed of elastic substructures having moderate elasticity and consisting of a face, outer shell, and inner structure in which said elastic substructures that cooperate so as to provide larger impulses to the ball at impact, due to combined elastic properties of the club face for hits at all locations on the face. This allows better distance of shots when loft angle and other design details are appropriately chosen. The structure also minimizes variations of angular orientation of the face surface at the point of impact for all such hits. The elastic substructures can take several forms such as an internal elastic support around the periphery of the face structure, an internal support for the central part of the face structure, and an elastic structure attached to the front side of the face structure, an elastic outer shell, and their combinations. The structure also provides adequate strength, and minimum weight such that a maximum amount of concentrated mass can be located in advantageous places as far as practical from the center of gravity of the head so as to realize maximum moments of inertia about the center of gravity.

What is claimed:  
     
         1 . A golf club head composed of parts which include an elastic shell, a face, and a central part located behind said face and said central part being inside of said elastic shell, elasticity of said head being defined by said shell in cooperation with at least one other member, said at least one other member being chosen from a group having elements consisting of said face, said face being elastic, said central part, said central part being elastic, and combinations of said elements of the group.  
     
     
         2 . The golf club head of  claim 1  wherein said face deforms between 0.02 and 0.10 inch for impact with a golf ball with approach velocity of 109 miles per hour, said impact being at any location on said face.  
     
     
         3 . The golf club head of  claim 1 , wherein said elastic central part comprises a layer of elastic material attached to the back side of a said face and to said elastic shell.  
     
     
         4 . The golf head of  claim 3 , wherein the said layer of elastic material has cavities therein that extend at least partially through said layer of elastic material for adjusting elastic properties.  
     
     
         5 . The golf club head of  claim 4 , wherein the cavities comprise holes through said layer of elastic material.  
     
     
         6 . The golf club head of  claim 4 , wherein said cavities comprise holes at least partially through said layer of elastic material.  
     
     
         7 . The golf club head of  claim 1 , wherein said central part is chosen to be an internal support having a ball striking surface exposed to the front side of said shell, said shell supporting said internal support, said internal support having suitable elastic properties so as to provide a desired normal coefficient of restitution for golf club and striking surface impact.  
     
     
         8 . The golf club head of  claim 7 , wherein said shell has a cross plate supported thereon spaced from the ball striking surface, said internal support being at least partially supported on said plate.  
     
     
         9 . The golf club head of  claim 3 , wherein said face comprises a sheet of material and the elastic properties of said layer of elastic material and said sheet of material joined thereto are varied by altering at least one of the factors chosen from the group consisting of thickness of the elastic layer, cavities formed in the elastic layer, and variation of thickness of the sheet of material, to control the local values of elastic and mass properties as measured at the face.  
     
     
         10 . The golf club head of  claim 2  wherein said elastic center part comprises a coil spring joined to the face, a front plate joined to an outer side of the coil spring, the coil spring comprising a series of coils with a coil diameter spacing the face and front plate.  
     
     
         11 . A golf club head comprising a shell having a ball striking face side and an opposite rear side, said shell defining a perimeter of the ball striking face side, said ball striking face side comprising a ball strike surface of a non-metallic member supported on said shell to at least partially carry loads from impact of a golf ball striking said ball striking surface and causing deflection of the said ball striking surface relative to said shell.  
     
     
         12 . The golf club head of  claim 11  wherein said member extends to the perimeter of the shell.  
     
     
         13 . The golf club head of  claim 11  wherein said non-metallic member comprises a plurality of deformable columns having first ends supported on a rear side of said shell, and second ends forming said ball strike surface.  
     
     
         14 . The golf club head of  claim 13  wherein said columns comprise a plurality of said columns at least some of which are joined by walls extending perpendicular to said ball strike surface.  
     
     
         15 . The golf club head of  claim 11 , wherein said non metallic member comprises a plurality of deformable walls formed into a honeycomb, the walls extending generally perpendicular to the ball strike surface.  
     
     
         16 . The golf club head of  claim 13 , wherein the said plurality of deformable columns are held by walls formed as a honeycomb structure.  
     
     
         17 . The golf club head of  claim 11 , wherein said non metallic member comprises a plurality of spaced apart walls generally perpendicular to said ball strike surface.  
     
     
         18 . A method of providing a desired coefficient of restitution for impact of a golf ball on a strike face of a golf club head after deflection caused by impact of a said golf ball on any location on said strike face comprising providing an elastic material between the strike face and a golf club head shell to transfer deflection loads from the strike face to said shell.  
     
     
         19 . The method of  claim 18  including forming said elastic material as an elastomeric layer having a strike face structure forming an outer portion of a face plate structure, providing a plate member carrying the elastomeric layer to the golf club head shell, and securing said plate member to said shell.  
     
     
         20 . The method of  claim 18  including supporting a plate member at a perimeter of the golf club head shell, adhering an elastomeric material layer on an outer surface of the plate member, and adhering a thin metal plate to an outer surface of the elastomeric material layer.  
     
     
         21 . The method of  claim 18 , wherein a striking face is on a plate member, and providing the elastic material between the plate member and the golf club shell.  
     
     
         22 . The method of  claim 18  wherein the strike face is formed on an end of the elastic material.  
     
     
         23 . A golf club head having a face structure, a ball impact surface on said face structure, a central part structure and a shell structure in which said face structure, central part structure, and shell structure have material and structural design such that said ball impact surface is able to deform elastically in a rearward direction at least 0.02 inch from impact of said ball at approach speed perpendicular to said ball impact surface of  109  miles per hour, at substantially any point on said face structure, the design and materials of said structures selected to thereby allow said face structure to deform and return elastically to increase the momentum transferred to a golf ball when struck by said golf club head with impacts normal to said ball impact surface at substantially all locations of impact of the ball on said ball impact surface and minimize changes in angular orientation of said ball impact surface during all such impacts, as compared with known designs of golf club heads having flexible features, which cannot so deform and return elastically.  
     
     
         24 . The golf club head of  claim 23  wherein said central part structure is composed of columns having long axes within  45  degrees of perpendicular to the center of said face structure ball impact surface.  
     
     
         25 . The golf club head of  claim 24  wherein said columns are generally perpendicular to the center of said face structure ball impact surface.  
     
     
         26 . The golf club head of  claim 25  wherein at least some of said columns are joined by flexible walls so as to transmit low force between adjacent columns in the direction of the long axes of such columns, and to transmit significant force from one column to an adjacent column to reduce the tendency of the columns to buckle.  
     
     
         27 . The golf club head of  claim 26  wherein said flexible walls are adjoined to selected ones of the plurality of columns forming the center part structure.  
     
     
         28 . The golf club head of  claim 23  wherein the material of said center part structure is one of the materials chosen from a group consisting of polycarbonate plastic, polyester plastic, ABS plastic and elastomeric materials.  
     
     
         29 . The golf club head of  claim 23  wherein said face structure is formed as a ball impact surface on a face end of said center part structure.  
     
     
         30 . The golf club head of  claim 23  wherein said shell structure is composed of a material chosen from a group consisting of polycarbonate plastic, polyester plastic, ABS plastic, and elastomeric materials.  
     
     
         31 . The golf club head of  claim 23  wherein said central part structure comprises a honeycomb cross section structure and is composed of material having Young's modulus of elasticity less than 500,000 pounds per square inch.  
     
     
         32 . The golf club head of  claim 31  wherein said honeycomb cross section has a cross sectional shape having open space defined by intersecting walls forming a geometric pattern.  
     
     
         33 . The golf club head of  claim 23  wherein there is a stiff and strong support plate behind the said central part structure, the said central part structure is made of elastomeric material, and said central part structure has a length in a direction substantially perpendicular to the ball impact surface of less than 0.3 inch.  
     
     
         34 . The golf club head of  claim 23  wherein there is a face structure between said central part structure and the ball impact surface, said central part structure comprising a tubular column of a selected cross sectional shape, said tubular column being disposed against the face structure so as to elastically support said face structure with respect to rearward movement of said face structure.  
     
     
         35 . The golf club head of  claim 34  in which said tubular column is in the form of a plurality of concentric telescoping metal tubes such that an innermost tube supports said face structure and is in compression during impact from a golf ball, and the inner most tube being joined to the next outer tube at rearward ends thereof, said next outer tube being in tension and being joined to a third outer tube at forward ends, an outermost one of said concentric telescoping tubes being joined to a rear portion of said shell structure of said golf club head.  
     
     
         36 . The golf club head of  claim 35  in which a plurality of said concentric telescoping tubes is disposed in selected locations on the face structure to provide support and stiffness of the face structure in desired locations to approximate desired strength and elasticity at substantially all locations of said face structure.  
     
     
         37 . The golf club head of  claim 25  wherein said central structure extends for a length L rearwardly from the face structure and the length L being at least 1.6 inches and within the shell structure.