Anti-tampering locking system
AssigneeMCI, Inc.
InventorElizabeth Doros
Life of this patent
Estimating the term…
Abstract
A locking system comprising a locking fastener having tamper-resistant features, and a special key having a bit at one end for engaging a socket in the head of the locking fastener to rotate the latter. The internal configuration of the socket corresponds to an external configuration of the bit, and the corresponding contour of the socket prevents the fastener from being turned by tools other than the special key. The fastener may have left-handed threads on its shaft and its head may be recessed in a counterbore in a closure part to prevent gripping tools from gripping an external surface of the head. The configurations of both the socket and the key may readily be made by economical metal working techniques.
Claims21
A locking system comprising:
- a fastener having a socket at one end of a shaft, and means at the other end of the shaft for engaging a retaining means upon rotation of the fastener;
- and,
- a key having a shank with a handle means at one end, and at the other end a bit receivable in said socket and adapted to engage a portion of said socket for rotating said fastener when said shank is rotated by said handle means, said bit comprising:
- a bit body defining an axial channel and an axial slot communicating with said channel and having a width less than a maximum transverse dimension of said channel,
- and a pin having a base axially receivable in said channel and a projecting part extending radially through and beyond said slot to form a tooth projecting laterally from the base of said pin,
- the base of said pin having a transverse dimension substantially greater than the width of said slot and opposing edge portions of said slot providing opposing undercut lips which extend over opposite side portions of the base of said pin and thereby serve as stops for engaging the base of said pin to secure said pin against lateral movement away from said bit body during rotation of said fastener with said key.
Dependencies are inferred from the claim text.