US Patent 7384345 Golf putter with rotary disc alignment aid

A putter head (1) is described wherein the putter head (1) has a putter face (4) and a linear marking (9) located on an upper surface (44) of the putter head (1). The relative angle of the putter face (4) with respect to the linear marking (9) is adjustable in order to compensate for inherent inaccuracies in a player's visual judgement when putting. In a preferred embodiment, the upper surface (44) is in the form of a rotatable disc (3) wherein the rotatable disc (3) is moveable about an axis in order to selectively adjust the relative angle between the linear marking (9) and the putter face (4).