Device for preventing falling of upper pin tumblers of a lock during change of a lock core in the lock

A lock assembly, comprising:

• a main body including a compartment defined in a lower part thereof for removably receiving a lock core therein, the main body further including a plurality of upper chambers defined in an upper part thereof, said upper chambers respectively including upper pin tumblers received therein, said upper chambers further respectively including lower ends, the lock core including a plurality of lower chambers defined therein, said lower chambers respectively including lower pin tumblers received therein, the main body further including a plurality of holes defined in a periphery thereof each longitudinally spaced apart a predetermined distance, said holes respectively being in communication with the lower ends of said upper chambers, and further including a member having a plurality of branches each spaced apart said predetermined distance, said branches being removably inserted into said holes to support said upper pin tumblers to facilitate removal of the lock core.