Yale & Towne Manufacturing Co., Stamford, Connecticut - 3
movements, Type D
The complete line of Yale Type A through G time locks pictured from left to right. The A was a unique prototype
piece. Only the
Type B through E series went into production. The G was only made as
salesman's samples. Since the Type A was a prototype and at the present time only one Type
C and complete G has been found, those facts makes this collection unique in that it
contains the complete set of all the examples. 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
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
The Yale Type D time lock, 1889, demonstration of winding and setting the
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
Yale Type D, c. 1892., missing base 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,
(1) American Genius - Nineteenth Century Bank
Locks and Time Locks, John and David Erroll, pp.