Hall's Safe & Lock Co, Cincinnati, Ohio - 2 movement with Burton-Harris bolt motor
A very curious and quite rare two movement configuration by Hall, c. 1876. The case design is unlike any of Hall's other chrome plated cases. This example has a gold plated jeweled (damascene) case very much in the manner used by Sargent & Greenleaf in their spotted case design. The size of the case is larger than in any of their other two movement models. There are no patent number and dates on the door as is found on the company's production models. This time lock case looks to be identical to one detailed in John Erroll’s book1. The time locks in the book, however, are Milton Dalton locks where here they are a Hall with a later Consolidated replacement. The snubber bar as well as the dial indicator are exactly as on the Dalton example. I believe this is why the the dials have been shifted clockwise by 120 degrees. In the Dalton example, the dial zero point is just to the left of the 12 o'clock position, and so the dials are shifted here to match that position and thereby be able to make use of the existing snubber bar and Dalton dial hand mechanism. Hall's standard dial indicators cannot be used with this configuration. It is also apparent that there are four extra holes drilled into each movement to match the existing mounting points in the case. Those points were designed for the original Dalton movements. It is amazing that so many holes were able to be drilled without damaging any of the clockwork within. The original Dalton example is in the Mossman Collection, at the General Society of Tradesmen and Mechanics Museum in New York City, photos below.
In Erroll's book his example is described as a a prototype that was never patented or put into production. Dalton's locks did not have the same configuration for the platform escapement as the Hall movement. In Dalton's design the escapement was on the front movement plate where in Hall's design the escapement is on the top, straddling the front and rear plates. Here is where it get's interesting. The case, if it were originally equipped with Dalton movements would not have had the top glass portholes since there was no escapement to be seen through them as there is with the Hall movements. So either this case had holes drilled into it and additional porthole glasses fitted to accommodate the later Hall movements, or this is another experimental trial at the Hall company at this type of design. Case # none, Hall movement # 2575, Consolidated movement # 2674. 6 3/8"w x 3 3/8"h x 2 3/8"d. Bolt motor # 894 file 168
The time lock is connected to a Burton-Harris bolt motor. This device has a powerful spring that when tripped by the time lock would throw the bolts open, thus releasing the safe door. The advantage of this system is the fact that the bolts do not have to be manually opened through an external crank. As long as the safe was in a secure location, there was also no need for a combination lock. The safe is set to open only when a trusted person is present This eliminates any holes in the door needed for the bolt crank or combination lock making for a much more secure door. Of course the owner must be sure that he is present when the time lock actuates the bolt motor or else it is open to anyone! The access into the door through these holes for safe crackers must have been a real problem otherwise why would anyone choose the inconvenience and risk of a safe that opened automatically? See another Burton-Harris bolt motor with an early S&G Triple A time lock.
A similar example in the Mossman Collection, at the General Society of Tradesmen and Mechanics Museum in New York City
1. American Genius Nineteenth Century Bank Locks and Time Locks, David Erroll & John Erroll, pg. 212-213