Chicago Safe &
Lock, Co., Chicago, Illinois - 2 movements - Gem model paired with James
Sargent's Rollerbolt Magnetic combination lock
On March 19, 1885 the Chicago
Safe & Lock Company located at 209-217 South Canal Street in Chicago
(currently the site of a high rise building; Chicago is this author's home
town), introduced their first time lock. The first order from the E. Howard Company
was for one-hundred units numbered from 500 to 600. This company had recently
acquired the services of Henry Gross who was a key employee and inventor at the
Hall safe & Lock Company. His patents, especially that of
February 8, 1876 formed the basis for that
company's line of time locks. Gross left Hall over disputes over patent royalty
payments. Later that year on December 11th Chicago Safe & Lock Company placed an
order with E. Howard for twenty new dials that bore the marking Gem Time Lock
Co., Gross Patents, Chicago, Ills. Thanks to this change, possibly an attempt to
avoid lawsuits, this lock is known as the Gem time lock. This author has seen a
few other examples of this lock but none have this designation on the dial.
(1) The example shown here is
serial number 501 making it the earliest known example and could be the first
lock installed by this short-lived company.
A more detailed
examination of the Gem time lock can be found here.
On this page we will examine in more detail the James Sargent Rollerbolt
Magnetic combination lock. Throughout the nineteenth century, European financial
institutions had equally well developed safe and vault technology as that of the
United States. However, while European inventors continued to introduce
innovative and elegant key locks, key lock development had substantially ended
in the United states by the 1860's. The broad acceptance of the dial combination
mechanism throughout the American safe and vault industry offered new security
challenges to safecrackers. With no keyhole, safecrackers increasingly turned to
drills, wedges, torches and the like, but those intent on defeating the
combination lock found that early designs were vulnerable to new methods of
attack. The image of the stethoscope-wearing safecracker is likely fictional,
since even the earliest combination locks were not so loosely made that the
fence could be heard on the tumbler gates. Rather safecrackers found that
pressure applied to the bolt handle, forcing the bolt against the tumblers,
allowed the manipulator to determine the tumblers' positions as the dial was
turned. James Sargent refined this cracking technique in the mid 1860's through
his invention of the micrometer (not to be confused with the instrument used
make fine measurements used). His device used a weighted armature
that attached to the bolt handle, thereby forcing the bolt against the tumblers.
The micrometer could magnify even miniscule movements allowing all but the most
exactingly machined locks to be opened. (2)
See illustration below. Interesting how Sargent used a pocket watch dial layout
instead of a decimal dial one might expect.
Using this objective test of the weakness of the then state-of-the-art
combination locks, James Sargent developed and patented his magnetic lock on
1865, which instantly placed him among the foremost bank lock makers. Sargent's
Magnetic Lock featured a powerful horseshoe-shaped magnet visible above the fence
and fence bar. The magnet held the fence up, off the tumblers except for a small
potion of the dial's rotation, making it nearly impossible for even a micrometer
to distinguish the tumbler's positions. The Sargent Magnetic also introduced a
new change key mechanism that required a second combination to be dialed in
before the change key could be used to alter the combination. This
combination-released change key mechanism would become an almost universal
feature of high quality combination locks for the next century. Sargent's first
model of the Magnetic Lock lock used a standard sliding bolt and was the first
model combination lock Sargent marketed.
His second model introduced a year later in 1866 featured another significant
feature, a rotating bolt or "rollerbolt" that moved the dogging action of the
lock from the tumblers themselves to the fixed bolt axle, further isolating the
tumblers from any attempt to read them through the boltwork. Sargent's
combination of the magnetic mechanism, the combination-released change key and
the rollerbolt made his second version one of the highest security combination
locks ever made.
The rollerbolt would be a major design element in Sargent's combination and
later, time locks for many years.
Sargent sold this lock in iron for $250 and in bronze as in the
example illustrated here for $300. Five examples of this lock are known today.
(3) See photos and video below
for an explanation of the lock's operation.
The first photo shows the front plate secured and one can see the keyhole
for the combination change key. The combination in this example is 50 L - 39
R - 15 L. Next a side view showing the rollerbolt in the 'off guard' or open
position and the dial and tapered dial spindle. The tapered spindle was
another anti-tampering design. If one attempts to force the lock with blows
to the dial or overwhelming torque, the spindle will snap off rather than
transmitting the force to the lock. The design is illustrated below.
The model 2 combination lock featured the rollerbolt for the first time. This was
James Sargent's most important innovation and was later carried over to the
time locks the S&G company produced, photos above. That design was later
refined into the 'cello bolt' which remained a standard until after WWII.
The magnetic system to hold the fence above the tumblers, another design to
thwart lock manipulation was introduced in Sargent's first model of combination
lock, and retained in this second version. The time lock shown is
S&G's model 2; the first commercially successful time lock produced. This
example the earliest known, s/n #49.
This video demonstrates the James Sargent Rollerbolt Magnetic combination
lock paired with a Chicago Safe & Lock Co., Gem model time lock. The time
lock dates from 1885. Both the time lock and this model of combination lock
are quite rare. The combination lock is the second model made by James
Sargent in 1866 and was produced one year before the partnership of Sargent
& Greenleaf was formed in 1867 with Colonel Halbert Greenleaf. The time lock was later fitted to the
combination lock around 1885.
Gem model, 1885. 4
5/8"w x 3"h x 2 1/4"d, Case #17, movement pair #501, the Gem
model serial numbering began at 500, making this the earliest known example; mounted to a James
Sargent Rollerbolt Magnetic combination lock, 7 1/4"w x 5 7/8"h x 2"d, #298.
Illustrated above are papers contemporaneous to the when the lock was made
in the mid 1860's. The first shows Sargent's model 2 Magnetic Rollerbolt
lock, the same as in this example. Notice the difference in the decoration
of the upper and lower plate shrouds. In the first picture they are simple
holes, something this author has yet to see. The advertisement states that
over five thousand of these locks are currently in use. This is
highly unlikely as very few are extant. One can see
the decorated plate shrouds as in this example as well as the way the
combination lock was arranged on the safe door in conjunction with a S&G
model 2 time lock. This combination lock is Sargent's Automatic, model 3
which did away with the magnet and used a series of three cams to perform
the same function. Notice the use of the rollerbolt in both the combination
and time locks. When both were simultaneously aligned with the door
boltwork, the bolt could be moved into the two recesses and the safe door
opened. A comment from this author on the movement of the time lock. The
extensive skeletonizing of the front movement plate has been illustrated in
some of the company's advertisements, but this style has never been observed
This extensive fretting of the plate would make it more prone to violence of
percussion or explosion and the first few production models did have some
cutout design around the central section and under the two dials which was
replaced a few years later with a solid plate for these reasons.
American Genius Nineteenth Century Bank Locks and Time Locks, David &
John Erroll, pp. 224
American Genius Nineteenth Century Bank Locks and Time Locks, David & John
Erroll, pp. 118
American Genius Nineteenth Century Bank Locks and Time Locks, David & John
Erroll, pp. 120