A drive ram (26) for use with a medical fluid injector may include a central, longitudinal reference axis (24). First and second gripper members (92) may be pivotally interconnected with a plunger engaging end (266) of the drive ram. Each of the first and second gripper members may be pivotable about a common pivot axis (95) that intersects the reference axis. Each of the gripper members may further include a first end (102) that is remote from the common pivot axis. In some embodiments, the first and second gripper members may be pivotable between a first position and a second position. In the first position, the first ends of the gripper members may be spaced apart by a first distance, while in the second position, they may be spaced apart by a second distance that is greater than the first distance.
