A self-centering mechanism for a rotatable shaft comprising: a first centering member defining a first arcuate slot and an opposed second arcuate slot; a second centering member defining a first arcuate slot and an opposed second arcuate slot; a rotatable shaft member extending through respective centers of the first and second centering members (10, 20) so as to be disposed between the first arcuate slots (11, 21) and the second arcuate slots (14, 24); a stationary pin extending through the first arcuate slots (11, 21) of the first and second centering members (10, 20); a support member extending radially from the rotatable shaft member, the support member being fixed with respect to the rotatable shaft member so as to be rotatable therewith and having an actuating pin extending therefrom and through the second arcuate slots (14, 24) of the first and second centering members (10, 20); and at least one biasing member (70, 70A, 70B) in communication with an anchoring structure and configured to rotationally bias the first and second centering member (10, 20) in opposed rotational directions to a registration position defined by interaction of the first arcuate slots (11, 21) with the stationary pin, wherein the actuating pin is responsive to rotation of the rotatable shaft member in one of the rotational directions to engage the second arcuate slot (14, 24) of one of the first and second centering members (10, 20) and to rotate the one of the first and second centering members (10, 20) with the actuating pin, and the one of the first and second centering members (10, 20) being responsive to the at least one biasing member (70, 70A, 70B) to rotate back to the registration position upon release of the rotatable shaft member. a first centering member defining a first arcuate slot and an opposed second arcuate slot; a second centering member defining a first arcuate slot and an opposed second arcuate slot; a rotatable shaft member extending through respective centers of the first and second centering members (10, 20) so as to be disposed between the first arcuate slots (11, 21) and the second arcuate slots (14, 24); a stationary pin extending through the first arcuate slots (11, 21) of the first and second centering members (10, 20); a support member extending radially from the rotatable shaft member, the support member being fixed with respect to the rotatable shaft member so as to be rotatable therewith and having an actuating pin extending therefrom and through the second arcuate slots (14, 24) of the first and second centering members (10, 20); and at least one biasing member (70, 70A, 70B) in communication with an anchoring structure and configured to rotationally bias the first and second centering member (10, 20) in opposed rotational directions to a registration position defined by interaction of the first arcuate slots (11, 21) with the stationary pin, wherein the actuating pin is responsive to rotation of the rotatable shaft member in one of the rotational directions to engage the second arcuate slot (14, 24) of one of the first and second centering members (10, 20) and to rotate the one of the first and second centering members (10, 20) with the actuating pin, and the one of the first and second centering members (10, 20) being responsive to the at least one biasing member (70, 70A, 70B) to rotate back to the registration position upon release of the rotatable shaft member.