Time Master Inc. (TMI), Topeka, Kansas

TMI series 2400, modern - manufactured in 2010. This is one of the electronic readout time locks. These time locks have never been as popular as the concurrently produced all mechanical time locks by this and other companies. Perhaps it is because of the need for annual battery changes or the lingering doubts about the reliability of the time lock should the batteries or some electronic component unexpectedly fail. According to the owner's manual the lock is designed to go off guard under these eventualities, but the perception is hard to overcome for what is essentially a very conservative industry. 4"w x 3.5"h x 2.5"d.  file 155

TMI was not the only company to produce an electronic version of a time lock. Sargent and Greenleaf as well as the British company Chubb tried their hands at this. Both also met with disappointing results. The point of these firms efforts was to eliminate the mechanical watch movements that were integral to all time locks since their introduction in the 1870's. Those movements required regular inspection and maintenance from a skilled person to ensure proper operation to the satisfy the bank's insurance company. But in the end, the electronic devices also require regular maintenance, if for no other reason than the replacement of batteries, let alone the problems associated with electronic component failures much to the chagrin of those same insurance companies. The tried and true designs of the mechanical movement proven over the past 140 years were simply more cost effective than the new approaches and to this day those mechanical time locks controlled by wind up mechanical movements are still in use today.