Patent ID: 8406993

Claim:
A system for retrieving shopping carts, the system comprising: a plurality of shopping carts, each of which includes radio frequency (RF) communication circuitry coupled to a braking mechanism, said RF communication circuitry being capable of receiving RF transmissions of commands; and a mechanized cart retrieval unit that pushes or pulls a group of nested carts to facilitate retrieval, the mechanized cart retrieval unit configured to communicate with the RF communication circuitry of the nested carts to cause the braking mechanisms of the nested carts to remain unlocked during mechanized cart retrieval; wherein the shopping carts are ordinarily responsive to detection of a lock zone created via a transmitter by locking their respective braking mechanisms, and wherein the mechanized cart retrieval unit is capable, via communication with the RF communication circuitry of the nested carts, of causing the nested carts to disregard the lock zone transmission signal.