Electronically controlled lock for releasing trolley to shopper in supermarket

摘要

The lock is an electronic version of the coin operated lock used in many supermarkets to release a trolley from an assembly of trolleys fastened to a post in the car park. The intending user inserts an identity card into a magnetic strip reader (2). If the card is recognised, a display (4) instructs the user to key (3) in a Personal Identification Number or PIN. The data from the user are communicated to the next trolley in the rack by an infra red signal link (5) and the lock is released. The data is fed back via the remaining trolleys to a memory in a central computer. When the trolley is returned and locked, the fact is recorded in the computer memory.