I have always understood the reason for wheels being fitted to American safes was to facilitate them being wheeled into the secure company vault at the end of business.
Where security against theft was required, such safes were either fitted with internal coffers (money chests) or had multiple layers of internal defence by means of secondary security doors plus coffers. (see illustration). This had then effect of reducing the storage capacity to an almost unacceptable level but meant that the weight of security barrier materials was kept to the minimum.
Spherical Safes had little capacity and were only suitable for securities, bullion, or cash.
Because of the nature of the Underwriter’s Laboratories test system large volume thief-resisting safes were a comparative rarity in the US. Jewellers, pawnbrokers, and the like, with large volume secure storage requirements therefore welcomed the importation of high volume cash safes in the ’70s such as Chubb, Tann, SLS, ISM, etc. which allowed complete window displays of watches, rings, etc to be stored. Previously they had to be dismantled for storage in the coffers.
Such imports had to meet the appropriate U.L certification such as Class TRTL-60×6.
