THE WORLD'S ADVANCE 



43 



A MODERN BANK VAULT DOOR 



The largest circular vault door and 

 vestibule ever constructed were recently 

 built at South Bethlehem, Pa. The enor- 

 mous size of the safe may readily be 

 imagined from the illustration in which 

 several men of average size have posed 

 to facilitate comparison by the aid of 

 the eye. 



In figures the vestibule is 10 feet 8 

 inches in diameter, the size of the door 



proper adjusting of which will permit the 

 door to be swung open. 



The door swings on a seven-ton cast 

 steel crane-hinge and is so well balanced 

 and adjusted that it can easily be swung 

 open by hand. In closing the door it 

 is forced to a watertight seat by means 

 of heavy pressure mechanism, thus pre- 

 venting the introduction of any liquid 

 explosive. The main vestibule weighs 

 51,000 pounds, while the main door with 

 the bolts and mechanism weighs 80,000 



The Largest Circular Vault Door and Vestibule Ever Constructed, on the Floor of the Factory, Ready 

 for Shipment. So Wonderfully Balanced is the Huge Door that it May be Swung Open by Hand. 



is 8 feet 8 inches outside diameter and 

 7 feet 8 inches inside diameter, or clear 

 entrance through the vestibule. The 

 door is 455^ inches thick and is con- 

 trolled by twenty solid steel locking bolts 

 5 inches in diameter, which are in turn 

 controlled by the latest design timelock 

 having four separate movements. The 

 operation of any of these movements re- 

 leases the mechanism, which in turn is 

 again checked by two of the largest and 

 most up-to-date combination locks, the 



pounds. The emergency vestibule alone 

 weighs 40,000 pounds. The resistance 

 one would encounter by trying to drill 

 the metal may be estimated at about 

 2,880,000 pounds per linear foot. 



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