Yale & Towne Manufacturing Co., Stamford, Connecticut - 4 movements, Quad K421 DAT

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The advent of ever stronger safes during the mid 1800's made the nighttime burglary more difficult to accomplish in the time available before opening time. Thieves then turned to what was known at the time as the "masked burglary" taking the proprietor or other person who knew the safe's combination and taking him to the premises to open the safe in the middle of the night. The time lock was invented to foil this strategy preventing the safe from access until the opening of business. This resulted in the early morning or even daytime holdup where the thief would come in just before or after opening time when the safe's time lock had gone off guard and making the personnel dial in the combination to the safe. This problem was quickly recognized by the security industry as evidenced by a number of patents applied for to circumvent this problem as early as the the late 1890's. But it was not until Yale  introduced the first commercially produced time locks for this purpose were made in 1932 based on a design by Charles Miller.

This example is only one of two types of time lock this author know that has two different sized movements within one lock. The first three movements are Yale L-movements with the last one a smaller, modified T-movement. The other time lock with two different movements is a rare Consolidated model.

The door plate is curious. What does it mean by the bolt work being locked open during banking hours? If the time lock is off guard as would any conventional time lock be at the beginning of regular business hours, the bolt work would be allowed to be opened by dialing in the correct combination. A time lock does not have the ability to keep the bolt work "locked open". It only has the ability to dog the bolt work, "locked closed", thus bypassing the combination lock, or in the case of a safe with an automatic bolt motor, keeping the door closed until the appointed hour of opening.



This is the only Yale to have a clamshell door design, similar to that used in many Sargent & Greenleaf models. It is also only one of two models Yale made to use a pushbutton door release in place of the handcuff key design and the only Yale to have a solid door. The part on the door that looks like a hinge with the three screws is actually a security device that fits into a recess in the case when the door is closed to prevent the door from being pried open from the hinge side should someone remove the door hinge pins. Obviously this security feature is completely obviated by the fact the door is opened by a pushbutton. Was there another option with a door lock?


The first drawing shows Charles Miller's design to retrofit the Yale Model T321, this was thought to be the only type of lock Yale applied this design to until the discovery of this Yale Quad K DAT. The second drawing shows another patent filed for the retrofitting of a Sargent & Greenleaf Model #4 to accomplish the same purpose of a short term, quick, emergency way to put the time lock on guard, but there is no evidence that S&G ever adopted it. An interesting observation is that the S&G model depicted in the 1933 patent drawing is the earliest S&G Model #4 made between 1879 and 1884 as evidenced by the dial and Geneva stop design. Eventually all of the mainstream manufacturers designed a specialized time lock for short term, intraday protection, S&G in their timebination series of locks in 1936, followed by Mosler in their Do-All series of locks and Yale's 6200 series.

Type Quad K421 DAT (Delayed Action Timer) c. 1932. A rare dual purpose time lock based on a patent by Charles A. Miller as illustrated above. This timer contains three conventional Seth Thomas 72 hour Type L movements and one modified Type T movement that has a 7 hour duration. Type T movements were the smallest coffin style movements made for Yale. A day/night switch is provided to engage the 7 hour movement during the day time hours. This lock would fulfill two functions. The first to act as a normal overnight/weekend time lock; using the two 72 hour movements and the second to secure the vault for short period of times during the day, primarily in the event of a daytime burglary. The 7 hour timer could be set for intervals as short as 15 minutes and when the DAY STOP knob is set that movement is stopped via a light lever touching the balance wheel, therefore that movement is always held in check for whatever amount of time has been dial in. In the event of a daytime robbery, the proprietor need only close the door, or more likely the door is closed, and then turn the bolt bolt actuator to trip the third short-term movement; by doing so the bolt is dogged for the amount of time previously dialed into that movement. Obviously a daytime yegg (the term yegg is actually used in the patent description and is an outdated term, first seen in 1901 for a robber) will not be able to wait around for the time lock to run down. The NIGHT STOP switch is used to disable the fourth movement from being able to be activated preventing it from accidentally putting the time lock off guard in the middle of the night, and is switched off during the day to allow the DAY STOP feature to work. Obviously one can readily see a danger here. If one forgets to deactivate the DAY STOP by setting the NIGHT STOP it is possible to set the short term timer running and put the lock off guard in the middle of the night. To see another Yale with modified Type T movements click here. Later, Yale improved the design by eliminating the "DAY STOP" knob; substituting a drive gear combining it into a single switch removing the problem of the lock being left off guard accidentally. Less than fifty of the first version were made, probably in recognition of this problem, with this being the only known example using the quad design. Case #18, L-movements numbered 14107, 14109, 27448, special timer movement T2758. 8" w x 4 1/4" h x 2 13/4" d. file 286

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