Electric contact structure for a locking cylinder

Abstract

A contact structure of a locking cylinder comprising a pair of contact pieces each extending laterally and pivoted at its one end about a pivot axis parallel to the axial line of the locking cylinder, a pair of springs, each urging the corresponding contact piece inwardly toward the center of the locking cylinder, a pair of stoppers which limit the inward motion of the contact pieces to the positions where they protrude slightly into a bore defined at the entrance to the key hole of the locking cylinder. The radially inner surfaces of the contact pieces of the locking cylinder define contact surface which electrically contact the corresponding contact pieces provided in the side edges of the base end of the shank of the key. This contact structure provides uninterrupted electric conductance between the key and the locking cylinder. To facilitate the insertion of the key into the key hole of the locking cylinder, a guide member may be fitted into the cavity defined between the contact pieces in front of the key hole so as not to interfere with the motion of the contact pieces.