US Patent 8109514 Card shuffling device and method

A device for shuffling a deck of playing cards is described. The cards are placed in a compartment having a shape of a rectangular parallelepiped, and dimensioned so that the cards are constrained in rotation in two of the three axes. The device is oriented so that a thickness dimension of the deck is horizontal, and groups of cards of the deck of cards are ejected in a vertical direction so as to provide a spacing of between a top edge of cards at rest and a bottom edge of the cards being ejected. The time duration of the ejection process is sufficient to effectively randomize the deck of cards. The ejection of cards may be by a plurality of pistons, and the pistons may be actuated by a motor, a solenoid or by air pressure.