A manually actuated robotic tool changer comprises master and tool units, each adapted to be connected to a different one of a robotic arm and a robotic tool. The tool changer includes a plurality of rolling members retained in one of the units and a piston mounted in one of the units and moveable in an axial direction. The piston includes a multi-faceted cam surface including an initial contact surface, a locking surface, and a failsafe surface interposed between the initial contact surface and the locking surface. When the piston is in a locked position in the tool changer, the cam surface is operative to contact the rolling members in one of the units and to urge each rolling member against a surface of the other unit to couple the master and tool units together.