US 6,484,545 B1Granted

Mechanical code comparator

AssigneeSandia Corporation

InventorsFrank J. Peter, Larry J. Dalton, David W. Plummer

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Abstract

A new class of mechanical code comparators is described which have broad potential for application in safety, surety, and security applications. These devices can be implemented as micro-scale electromechanical systems that isolate a secure or otherwise controlled device until an access code is entered. This access code is converted into a series of mechanical inputs to the mechanical code comparator, which compares the access code to a pre-input combination, entered previously into the mechanical code comparator by an operator at the system security control point. These devices provide extremely high levels of robust security. Being totally mechanical in operation, an access control system properly based on such devices cannot be circumvented by software attack alone.

Claims8

Dependent claims

A mechanical code comparator which compares an access code entered from an open side to a security code entered from a secure side, comprising:

a) multiple coded elements, each comprising multiple index features, a coded index feature, and a try bar feature;
b) an indexing mechanism which engages index features on each coded element and aligns them with a neutral position and wherein the indexing mechanism comprises:
a) a unidirectional shuttle actuator;
b) spring means to hold the actuator in a neutral position in the absence of applied force;
c) an indexing shaft functionally connected to the shuttle actuator and comprising a guidance pin;
d) bearing means to restrict the indexing shaft to linear motion;
e) a bi-directional indexing actuator having an output and secure and open control lines;
f) spring means to hold said actuator in a neutral position in the absence of applied force;
g) a flexible member functionally connected to the indexing actuator output;
and
h) an indexing cage functionally connected to the flexible member, and comprising an indexing tab and a guidance pin notch within which rides the guidance pin;
c) a secure drive for entering the security code via the indexing mechanism;
d) an open drive for entering the access code via the indexing mechanism;
e) a try bar comprising a try bar key for each try bar feature, such that the try bar is only free to move to an unlocked position if the multiple coded elements are positioned so that the try bar keys can fully engage the try bar features;
and
f) a try bar drive.

13 more elements

Dependencies are inferred from the claim text.