Patent ID: 6016677
Filing Date: 2000-01-25
Classification: E05B,G07C,Y10T

Abstract:
An tamper-evident arrangement for use with a keypad unit of a lock system, the arrangement comprising:a) a keypad cover;b) a keypad base;d) a magnet and Reed switch, arranged in a first one of the keypad cover and keypad base;d) a metal piece, attached to a second one of the keypad cover and keypad base, so that:1) when the keypad cover and keypad base are assembled together, the metal piece absorbs magnetic flux lines from the magnet so that the Reed switch is in a first state; and2) when the keypad cover and keypad base are not assembled together, the metal piece does not absorb the magnetic flux lines from the magnet so that the Reed switch is in a second state opposite to the first state; ande) means, responsive to the state of the Reed switch, for sensing whether or not the keypad cover has been removed from the keypad base.