Interlogix, Inc.

Supra Products, Inc.

Slc Technologies

Charles E Burleigh

Wayne F Larson

Matthew S Hill

Various enhancements are provided to a pushbutton lock to enhance its security. One is the provision of button tips that are mounted on the ends of the button assemblies and spring-loaded to protrude from the face of the lock, regardless of whether the underlying button is &ldquo;in&rdquo; or &ldquo;out.&rdquo; By this arrangement, a bystander cannot readily see the button combination by the pattern of depressed buttons. This arrangement also reduces tactile feedback between the underlying button assembly and the externally available button tips, increasing resistance to pick attacks. A further enhancement is the provision of button bars between adjacent pairs of button tips. Whenever any of the button tips is manually depressed, the corresponding button bar is pressed into engagement with, and prevents movement of, a member that must be moved in order to unlock the lock. This arrangement further increases lock security by preventing an attacker from experimentally pressing buttons and judging the tactile effect thereon in attempted unlockings of the lock.

Pushbutton lock

Various enhancements are provided to a pushbutton lock to enhance its security. One is the provision of button tips that are mounted on the ends of the button assemblies and spring-loaded to protrude from the face of the lock, regardless of whether the underlying button is 'in' or 'out.' By this arrangement, a bystander cannot readily see the button combination by the pattern of depressed buttons. This arrangement also reduces tactile feedback between the underlying button assembly and the externally available button tips, increasing resistance to pick attacks. A further enhancement is the provision of button bars between adjacent pairs of button tips. Whenever any of the button tips is manually depressed, the corresponding button bar is pressed into engagement with, and prevents movement of, a member that must be moved in order to unlock the lock. This arrangement further increases lock security by preventing an attacker from experimentally pressing buttons and judging the tactile effect thereon in attempted unlockings of the lock.

A lock includes a face plate into which a lock cylinder is mounted. Extending from the rear side of the face plate is a frame for supporting the back of the lock cylinder. A cover plate covers the front of the lock cylinder and includes one or more arms extending through the face plate to the back thereof, where the arms are secured against the plate. By this arrangement, the cover plate is secured to the back of the face plate, preventing removal of the lock cylinder by prying. The frame secures the lock cylinder to the rear, preventing it from being dislodged by hammer blows. Against all such attacks, the full structural integrity of the face plate serves to keep the lock cylinder in place and the lock secure.

Method and apparatus for lock mounting

A combination lock for a key safe has an over-center spring for biasing a unitary bolt in an extended or retracted position. A switch for actuating the bolt has a break-away button to foil vandals. The bolt includes checkers for engaging notches in a plurality of programmable combination rings when the combination is properly dialed. The checkers have V-shaped ridges for engaging false notches formed in the combination rings, making the lock pick-resistant. The checkers also include flat shoulders to prevent the bolt from being forcibly wedged into the combination rings to open the lock. The combination must be properly dialed to permit the bolt to be retracted for closing the key safe.

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Salem, OR, United States of America

Charles E Burleigh