Patent ID: 7494077

Claim:
A two-way self-lock paper shredder having a functional switch ( 11 ), a shredding mechanism ( 10 ), a control circuit power source ( 2 ) electrically connected to functional switch ( 11 ), and the following control circuits: CPU ( 1 ); motor driving circuit ( 8 ), one end of this circuit is connected with CPU via electrical connection and the other end is connected with shredding mechanism ( 10 ) via electrical connection, is used to drive the shredding mechanism ( 10 ) to run; reverse detection circuit ( 9 ), one end of which is electrically connected with CPU ( 1 ) and the other end is connected with shredding mechanism ( 10 ) via electrical connection, is used to detect the reverse signal and transfer such reverse signals to CPU ( 1 ), so that the CPU ( 1 ) will control the shredding mechanism ( 10 ) to reverse; paper detection circuit ( 5 ), one end of which is electrically connected with CPU ( 1 ) and the other end is connected with a control circuit power source ( 2 ), is used to detect the paper-in signal; when the paper is put into the inlet of shredding mechanism ( 10 ), the paper-in detection circuit ( 5 ) will transfer the paper-in signal to CPU ( 1 ) for processing and then motor-driving circuit ( 8 ) is conducted and drives shredding mechanism ( 10 ) to run; if there is neither an input of paper-in signal nor the reverse signal after the paper is shredded, the said paper-in detection circuit ( 5 ) will transfer a self-lock signal to said CPU ( 1 ) and the CPU will begin timing; if the duration of said self-lock signal exceeds the preset value, CPU ( 1 ) will shut off the motor-driving circuit and paper shredder will be self-locked; unlocking circuit ( 4 ), one end of which is electrically connected with CPU ( 1 ) and the other end is connected with a control circuit power source ( 2 ), is equipped with unlocking key (K 1 ); when the paper shredder is in self-locking, unlocking circuit ( 4 ) will transfer the unlocking signal to CPU ( 1 ) if unlocking key (K 1 ) is reset, so that CPU ( 1 ) will take control to close motor-driving circuit ( 8 ) and then the paper shredder will be unlocked.