Yale & Towne Manufacturing Co., Stamford, Connecticut - 3 movements, Type D

Back Up Next

In 1887, Yale patented a time lock design that would mark a new direction for Yale and, eventually, the entire time lock industry: its Type B and Type C time locks, which went into production in 1888. Based on pocket watch movements rather than on the larger clock movements of the Pin Dials, these smaller-format movements were inherently suited to be individually replaceable or "modular" movements. These were also the smallest format three movement time locks made to that time. Yale would not have a smaller three movement design for bolt dog release until the model T321 introduced about 1900 and would never surpass the compact Yale C and E designs for the automatic release function. No other time lock manufacturer made a smaller three movement lock. With the introduction of the Type D, Type E and Type G time locks, Yale debuted their own line of automatic bolt motors. The Type D and Yale automatics were soon popular with banks and businesses with regular hours, used in the new "solid door" safes, a safe with no key hole or combination lock spindle, handle or any other connection to the outside, that relied solely on the high-quality time lock and automatic bolt motor. (1)

The line of Yale Type B through E and EE time locks pictured, upper row from left to right. The lower row shows A and G.

Only the Type B through EE series went into production.

The A was a unique patent prototype piece and was never slated for production. The G was only made as salesman's samples. At the present time only one Type C, EE and complete G has been found. Like the EE shown, Yale did make one or two BB, and three DD locks, none of which are known to survive. There were no records of a CC being made. These facts makes this collection unique in that it contains the most complete set of all the examples extant. No records for or examples of a Type F are known.

The second generation models as represented by Type D and E did away with the movement disk being turnable for the purposes of winding and replaced it with a central winding square upon which is also mounted the setting dial hand. The method of reading the time is now reversed by using fixed dial around the perimeter and a moveable hand that rotates as one winds the time lock to show the correct time duration until the lock would go off guard. These was a great improvements over the more fragile and harder to read system as represented in the earlier design. Since one did not need to grasp the movement disk as it was now a fixed piece in which the watch movements are mounted, it could now be sealed within the case with only a hole needed through the front glass for the winding key as is common in many time locks. This also allowed Yale to dispense with the expense of an external case of the Type B to protect the moveable disk and the gearing behind it from abuse and dirt. The greater ease of use and accuracy of the new winding system, dial design and bezel overwind stop flag allowed Yale to dispense with the overwinding pins. (1)

Front elevation of the Type D with glass bezel attached. Unlike the screw-down bezel of the Type A and the bayonet style of the Type C, this one had a keyed slot that allowed it to only go in one position. Once seated the bezel could be rotated. This was essential since the introduction of the overwinding stop flag which had to be positioned so as to always be ahead of the pointer to perform its function, this is the red pointer near the 12 o'clock position.

Front elevation of the Type D with glass bezel removed. Note the larger, better defined dial numbering.


Three quarter view with glass bezel attached and next with bezel removed. The dial numbering is more readily seen.


Upper three quarter view, note the "Stop Pin" at the 3 o'clock position (not to be confused with the overwinding stop flag). This was a feature added with the the Type D to keep the lock off guard after the movements had been wound. Next the main components of the Type D.


The first photo shows the components of the bolt dogging system in the Type D. The sliding bolt is shown in the circled area with the case back on the left. That bolt is moved by the lever pointed out by the black arrow. The red arrow shows the area where a pin connected to the rear dogging lever system protrudes through the plate to connect with the release wiper on the time lock movement plate, that wiper performs the same function as the release pin on the Type B and C. The small white arrow shows where the stop pin is located and where it would block the bolt dog from engaging if it were to be pushed in to the set position. The second photo shows a close up of the Stop Pin. The design of this pin closely matches the pins found on the Yale Model 1, the Double Pin Dial. Pushing this pin in blocks the bolt dogging lever and allows the operator to put the lock off guard after the time lock has been set so the safe can be used before closing for the night. However, unlike this same function offered contemporaneously by the Consolidated Time lock Co.,(see video for demo), and Holms Electric Time Lock, Co. years earlier, this function was not automatic. In other words after the operator manually put the lock off guard, the time lock would automatically turn off the manual override at a preset time, presumably at the time the safe was to be closed for the night. In the Yale example if the operator forgot to pull the pin to its outward position, the lock would remain off guard permanently. Considering that the pin was very small and it was visually difficult to tell in what position it was in, it would be easy for someone to overlook that the stop pin was set and the time lock disabled. In the opinion of this author, it was a serious and dangerous design flaw. Yale did not use this stop pin method in any other model, however a disarming device was reintroduced as an option in their Triple O debuting in 1894. But that override had a large, highly visible "OPEN" flag to remind the operator to turn off the override. Still one could ignore or overlook the flag, close the door for the night and be unprotected. Never as good as an automatic re-arming system.


The first photo shows the stop pin in its outward, "off", position and its proximity to the bolt dog lever. The seventy-two shallow drilled holes around the bezel mounting collar serve as click stops for the rotating bezel to set the the maximum winding time through the introduction of a stop flag; to avoid overwinding. This was introduced in the Type D and E locks to correct for the problem of overwinding that plagued the Type B and C models. The second photo shows a red stop flag near the 12 o'clock position, at 72 hours on the dial. That pin is attached to the bezel and can be moved over the entire seventy-two hour dial. In it's current position the lock can be wound the entire duration of seventy-two hours. Rotating the bezel counterclockwise causes the pin to move to smaller numbers; limiting the amount of time the lock can be wound since the dial pointer cannot move past the pin. Thus, if the safe was to be closed at 5:00 PM and reopened the next day at 8:00 AM, the red pin  was set to fifteen hours, and the lock could not be overwound. A simple, effective remedy to the problem of overwinding; and could be changed for weekend operation. The operator had to be sure to return the stop pin back to weekday hours on Monday, or the safe would not open at the correct time Tuesday morning. Obviously the responsibility of setting a time lock was a serious one. The stop flag was also a feature in the Type G.


The Yale Type D time lock, 1889, demonstration of winding and setting the movement.

Yale Type D, 1890. The Yale Type D was the model which used a bolt dog to stop the safe bolts from being withdrawn and was the successor to the Type B of 1888. The company of E. Howard & Co. and later, after 1902, Seth Thomas supplied nearly all of the movements for Yale time locks (until the 1950's when movements from Switzerland were used). An exception are the Yale Type B through G models which used a modified version of a pocket watch; size #14, model 84 movements by American Waltham Watch Co. A smaller Waltham movement was also later extensively used in Mosler time locks. The movements were designed with anti-magnetic qualities - cutting edge technology for the day. The Type D was introduced to correct some of the design deficiencies found in the earlier Type B, those being the problems of overwinding, the difficulty of handling the fragile rotating movement base, and setting the time due to the small dial numbers and recoil of the movement springs through the motion of the rotating base. Yale introduced a rotating bezel with a stop flag which prevented overwinding. And a manual over ride "stop pin" which was a flawed device, never to be repeated on later products.

Yale sold a total of 62 Type D's between May 1889 and June 1892. There are five examples of the Type D known. This is the same example as illustrated in American Genius, page 244. 4.5"w X 5"h x 3"d. Case #28, movement plate #25, movements, #4527442, #4653511, #4658512. file 206


Yale Type D, c. 1892., missing base bolt dogging case. Same time lock as as example above. The lock has the closest set of movement serial numbers this author has seen in any of the Type B through E lock series.  4.5"w x 5"h x 2.5"d. Case #36, plate #280, movements #4658505, 4658556, 4658586. file #129

An interesting aside is the fact that both Seth Thomas and E. Howard were companies that made a full line of clocks and watches. From large tower clocks (for public buildings) to domestic clocks to watches as well as movements for time locks. Click here to see a medium sized Seth Thomas and Howard tower clock.

Below an example of a Yale Type D from the Harry Miller collection, Nicholasville, TN

Back Up Next

 (1) American Genius - Nineteenth Century Bank Locks and Time Locks, John and David Erroll, pp. 244-246