Mosler Lock Co., Covington, Kentucky - 3 movements, Model Triple D

Sometime in the late 1920's the Mosler company moved from Hamilton, Ohio to Covington, Kentucky. It appears a separate subsidiary, the Mosler Lock Company, was created for time lock manufacture at this time.

c. 1920's. This Mosler is a three movement case that was equipped with only two movements; leaving a blank plate in the middle. It is equipped with 18-size Model #4 pocket watch movements supplied by the Illinois Watch Company, making this prior to 1932. After that date Mosler shifted to American Waltham Co. 16-size pocket watch movements. Occasionally a customer did not want to pay for three movements, but had a safe that was configured for a three movement case. What makes this example interesting is the type of bolt dog mechanism employed as well as an additional overriding locking cam device. This lock uses a conventional roller bolt and is exposed in a position below the timer movements. This design was first developed by Sargent and Greenleaf. In fact the round design of this bolt dog harkens back to their earliest round bolt dog design of 1874.

Another unusual feature is the single lobed cam depicted by the red arrows. The slide located directly beneath the timers is moved to the right as the timers wind down to zero, and this action causes the roller bolt to turn clockwise, allowing the safe's bolt work to slide past the roller bolt, enabling the safe to be opened. When the cam is rotated a quarter turn from the six o'clock position to the nine o'clock position the slide is prevented from fully retracting and leaves the roller bolt in a closed or 'dogged' position even when the timers are fully wind down to zero. Notice that this cam is meant to be connected through the rear of the case which would have been mounted directly to the inside of the safe door. As explained in the Mosler catalog, this feature is connected to a dial on the front of the safe, presumably denoted in minutes up to sixty. Operating this dial causes the lock to go 'on guard' for the time specified between a few minutes to one hour. It seems to be a very specialized need, one not normally encountered making this lock fairly rare. 6 5/8"h x 5 7/8"w x 2 7/8"d. case #7787 D. file 166