Photo taken with glass removed.
The first photo shows a close up of the E. Howard platform
escapement. Introduced in 1875 in their Model 1 this was a major design
improvement from Sargent and Greenleaf's movement designs introduced in 1874
with regards to serviceability of the time lock. As described in the opening
chapter describing A Brief History of the Time Lock Industry, all
of the manufacturers required an annual inspection of their time locks to
keep their guarantee against a lock out and this was supported by the bank's
insurance company. Most often if a movement gave trouble it was located in
the upper portion of the train, the balance wheel, escapement, or escape
wheel. At this time S&G did not employ a module that contained these parts.
Only the balance wheel was separable from the rest of the movement. The
remaining escapement and escape wheel were still contained within the same
set of plates that held the rest of the wheel works and main spring. Yale's
design is known in horology as a 'platform escapement'. With the
introduction of Yale's model #1 aka the Double Pin Dial, E. Howard employed
their watch production expertise to create this for ease of service. The
platform was not commonly used in pocket watches where the individual
components of the upper train were not mounted to a common frame. It seems
the Howard company developed this for the time lock industry, although the
concept of the platform was well known prior to this time in the manufacture
of carriage clocks. This feature allowed for interchangeability between
movements of the entire platform assembly since the next wheel down the
train was a common wheel. The very tight tolerances needed for movement
components the the size of a pocket watch at this time were too tight to
allow interchangeability of any of the components within any platform.
Although an entire time lock movement was considerably larger than a pocket
watch, the upper train components containing those parts within the platform
assembly were pocket watch size. The top, transverse, mounted platforms used
by Hall were not interchangeable. By the time that company was
reincorporated into the Consolidated company in 1880 these still were not
interchangeable until about the late 1890's.
With the introduction of modular movements by Yale by 1887,
S&G in 1889 the usefulness of the platform in servicing became obsolete
since the safe tech could simply swap out the movements without resorting to
any of the skills necessary for work on the movement itself. The defective
movement would then be sent back to the firm for in-house service. While
somewhat rare compared to the total numbers out there, the fact that there
are many three and even four movement time locks that still have the
original consecutive numbered movements is a testament to their reliability
since none had to be swapped out for service. Once swapped out the original
movement was rarely ever returned. Of course another option was for the bank
to operate on one less movement which was possible and still quite safe in a
three or four movement configuration and have their movement serviced
locally and replaced when repaired. But this was rarely done as insurance
requirements would not allow this option.
These are the drawings from Emery Stockwell's original patent for the Double
Pin dial dated September 21, 1875, the same year Yale introduced their Model
1 time lock based on this design. Mr. Stockwell was one of the important
inventors in the time lock industry along with James Sargent, Henry Gross
and Milton Dalton to name a few.
Yale Model No: 1 c.1880. Double Pin-Dial Time lock (1).
This was Yale's first time lock, and is probably one of the finest, complex and more
beautiful ever made. Available with either 56 hour or, after 1885, 72 hour movements. An
extremely expensive item as the standard version was $400. A day of the week attachment,
Sunday Attachment (2), was available for an extra
$50. This lock is prior to the advent of the 'modular design' where individual movements
were interchangeable. The movements were made by E. Howard & Co., Boston, one of the
finest watchmakers of the period. Howard continued to supply Yale as well as other
companies (Consolidated, Diebold) with movements until exiting the business
around 1902. Although a complex and
expensive lock, it was popular and Yale made over 2100, therefore this lock for it's age
is fairly common with over 400 known survivors of which 50 have the Sunday Attachment
option. However Yale offered a rebuild of the earlier 56 hour movements for
$30 and many were converted, so the 56 hour model is quite rare. Movement #1227, case #1321. file 100
A feature unique to this type of time lock (pin dial) is that as
well as being ' off guard ' it can go ' on guard ' in accordance with the settings of the
pins. As such it is designed to run continuously, unlike the majority of time locks which
go off guard when they run down. However, if the movements are allowed to stop completely
they will take the lock off guard, despite the settings of the pins. Compare this model to
the Yale single pin dial (a much rarer version).
Below is a Diebold safe equipped with a Yale double pin dial.
The medallions are on
Yale’s Double dial bank lock with the two sides of the Paris exposition medal of
1876 where it won silver. The portrait is of Napoleon III.
This is an example of cross branding
in the time lock industry. Diebold had not yet at this time entered into the time lock business so
the Yale was added as an 'after market' product. What's even more
interesting as that this safe used Yale equipment for the combination locks
so this was an installation made before Diebold entered the time lock
business in 1916.
An original Yale advertisement c. 1876. Notice that the time lock is
(1) The pin dial is clearly a far more
complicated design than Sargent & Greenleaf's Model 2,
offered a number of innovations, the most obvious being the two front dials, each with
series of twenty-four pins. Every pin, embossed with an hour of the day, could be pushed
in, locking it, making the Pin Dial the first time lock capable of both unlocking and
locking a safe at a predetermined time. Further the Pin Dial was the only mechanical time
lock ever to be able to lock, unlock, and re-lock a safe for various one-hour periods
throughout the day. American Genius Nineteenth Century Bank Locks and Time Locks,
David Erroll & John Erroll, pp 164.
(2) In 1876 Yale added the Sunday Attachment, which allowed
the lock to skip the opening periods each Sunday. The mechanism is identified by two
curved nickel runners next to the inner top third of the pin dials embossed with
"Thursday Friday Saturday" and a small shield on each dial that is geared to
rotate at one-seventh the rate of the dial. These shields move over the the names of the
days, allowing the user to check to make sure it is accurate, and then, during the twelve
hours Sunday day, will be interposed between the drop wheel and the pins, guarding the
opening of the pulled pins and keeping the lock shut. This option was available after
1885. American Genius Nineteenth Century Bank Locks and Time Locks, David Erroll
& John Erroll, pp 164.