US Patent 9422744 Burglarproof primary-secondary row sheet lock

A burglarproof primary-secondary row sheet lock includes an outer cylinder in which a cylindrical chamber that receives the insertion of a plug and a latch trough are formed. The plug includes row sheet receiving slots, a latch opening, a key way, and a lock bolt. The secondary row sheets each have a side edge in which a first latch notch is formed. The primary row sheets are each formed with a secondary row sheet channel and a second latch notch. The primary row sheets are set in the row sheet receiving slots and the secondary row sheets are received in the secondary row sheet channels. The closure plates cover the row sheet receiving slots with sheet return springs arranged between the closure plates and the primary and secondary row sheets. The latch is received in the latch opening and latch return springs are arranged between the plug and the latch.