Adjustable golf club and system and associated golf club heads and shafts

A golf club head comprising:

• a body defining a ball striking surface, a crown, a sole, a hosel, a heel, and a toe;
• and
• an adjustment member engaged with the body and having a hosel adapter, wherein the hosel adapter comprises a first rotation inhibiting structure and an off-axis bore hole;
• a shaft adapter with a second rotation inhibiting structure that engages the first rotation inhibiting structure, a spherical member, an off-axis bore hole, and a shaft adapter axis, the spherical member of the shaft adapter operably connected to the hosel adapter and rotatable about the shaft adapter axis, and
• wherein the body and the adjustment member are structured such that the adjustment member independently adjusts a specific combination of a loft angle and a face angle of the body among a plurality of loft angles and a plurality of face angles, wherein in response to the independent adjustment of the loft angle and the face angle, a parameter associated with the body remains substantially unchanged within a predetermined tolerance, wherein the parameter is one of the following:
• the golf club head's location of a center of gravity, a face center, or a sole contact point, wherein each location is measured from a hosel origin point located at an intersection of the shaft adapter axis and an uppermost edge the shaft adapter, wherein the off-axis bore hole engagement between the hosel adapter and shaft adapter allows for independent adjustment of the loft angle or the face angle, and further wherein when the parameter is the location of a center of gravity of the golf club head, and the predetermined tolerance for the location of the center of gravity is approximately 3 mm from a reference center of gravity determined before the adjustment of the loft angle and the face angle, and
• wherein when the parameter is a location of the face center of the golf club head, and the predetermined tolerance for the location of the face center is approximately 3 mm from a reference face center determined before the adjustment of the loft angle and the face angle, and wherein when the parameter is the sole contact point, the predetermined tolerance for the location of the sole contact point is 4 mm from a reference sole contact point determined before the adjustment of the loft angle and the face angle.

A golf club comprising:

• a golf club head that includes a body defining a ball striking surface, a crown, a sole, a hosel, a heel, and a toe;
• an adjustment member engaged with the body and having a hosel adapter, wherein the hosel adapter comprises a first rotation inhibiting structure and an off-axis bore hole;
• a shaft adapter with a second rotation inhibiting structure that engages the first rotation inhibiting structure, a spherical member, an off-axis bore hole, and a shaft adapter axis, the spherical member of the shaft adapter operably connected to the hosel adapter and rotatable about the shaft adapter axis;
• and a shaft connected to shaft adapter and the golf club head,
• wherein the body and the adjustment member are structured such that the adjustment member independently adjusts a specific combination of a loft angle and a face angle of the club head among a plurality of loft angles and a plurality of face angles, wherein the off-axis bore hole engagement between the hosel adapter and shaft adapter allows for independent adjustment of the loft angle or the face angle,
• wherein in response to the independent adjustment of the loft angle and the face angle, one or more parameters associated with the body remain substantially unchanged within a predetermined tolerance,
• wherein a first parameter is defined as a location of a center of gravity of the golf club head measured from a hosel origin point located at an intersection of the shaft adapter axis and an uppermost edge the shaft adapter and the predetermined tolerance for the location of the center of gravity is approximately 3 mm from a reference center of gravity determined before the adjustment of the loft angle and the face angle, and a second parameter is defined as a location of a face center of the golf club head measured from the hosel origin point, and the predetermined tolerance for the location of the face center is approximately 3 mm from a reference face center determined before the adjustment of the loft angle and the face angle, and a third parameter is defined as a moment of inertia of the golf club head about any one of an X-axis, Y-axis, or Z-axis, wherein the predetermined tolerance for the moment of inertia is approximately 10.0 KG-mm2 from a reference moment of inertia.