Lock for a safe deposit box

摘要

A safe-deposit box uses a lock using a tongue, a first mechanical device, a second mechanical device, an electromagnetic valve, a control unit and a keypad. A renter's key drives the first mechanical device from a first position to a second position for actuating the control unit. The electromagnetic valve is in a first position for retaining the first mechanical device in the second position. A code is input through the keypad to the control unit for driving the electromagnetic valve from the first position to a second position for allowing movement of the mechanical device from the second position to a third position for retracting the tongue. A clerk's key can drive the second mechanical device from a first position to a second position for driving the electromagnetic valve from the first position to the second position and turning off the control unit. If the code is forgotten, the second mechanical device is driven from the second position back to the first position for retaining the electromagnetic valve in the second position for allowing the movement of the first mechanical device from the first position to the third position. If the renter fails to pay rent for the safe, the second mechanical device is driven from the second position through the first position to a third position for driving the electromagnetic valve back to the first position for preventing the movement of the first mechanical device from the first position to the third position.