A Cardan lift uses the Cardan gear mechanism to convert rotation into reciprocating linear motion. It consists of an arm attached to a gear orbiting a stationary sun gear with a 2:1 gear ratio and an idler gear in between. A simple claw attached to the arm will hold the balls securely during travel. An early GBC implementation was done by Torbjörn Söderstedt.
To give the balls more time to enter and exit the claw, a special gear train which has two dwell periods 180 degrees apart can be used. One dwell period is used to load balls into the lift mechanism and the other is used to dump them.