Those without a sense of the history of the mechanical
watch probably do not know that were it not for the innovation of Patek
Philippe in 1841–with the invention of the “keyless works”–we might
still be winding and hand setting our wristwatches with a key. Although
now taken for granted, the crown and associated gearing of the modern
watch–which, miraculously, both winds the watch and sets the hands–is
an extremely clever piece of engineering. One measure of the success
of the design is that the virtually the same concept is used in every
mechanical wristwatch produced today.

The
keyless works provides the average watch owner, who does not disassemble
his watch, with his entire relationship to the actual mechanism on his
wrist. It is thus both our connection to the movement, as well as, unfortunately,
our opportunity to abuse it. Thus, after explaining the operation of
the keyless works, I will also discuss the proper way to use the crown
in both hand setting and winding. (The keyless works is connected to
the motion works, the under-dial mechanism that powers the hands.
The motion works is covered in a companion article, The Motion Works,
also appearing on the Horologium this month).

THE CONCEPT

Because the nomenclature of the parts of the keyless
works varies more dramatically (between the U.K. and the U.S.) than
in any other part of the watch, I will use the British nomenclature
(with which I am more familiar) throughout the article, but include
American terminology in parentheses when first introducing a part. While
details between designs varies, virtually all modern watches employ
a keyless works of
similar concept with eight essential parts. The heart of the keyless
works is the castle wheel (clutch in the U.S., 4 at left).
Additional parts always include the stem (the shaft to which
the crown is attached, 1); pull-out piece (setting
lever or detent) and pull-out piece screw (detent
screw) (2 and 2A respectively); pull-out piece
check spring (detent lever, 3); crown gear
(winding pinion, 4a); and castle wheel lever (clutch
lever, 5). In the illustrated IWC cal. 887, there are two
additional components for the seconds hack (or seconds stop when
the crown is pulled out), indicated at 6 and 7. These
are the stop operating lever (6) and the stop lever
(7). The curved upper end of the stop lever contacts the balance
wheel rim and arrests its motion when the crown is pulled full out to
the hand-setting position.

Though not associated with the keyless works, the
illustration also indicates the jeweled lower mainspring barrel pivot
(blue arrow), the backside of the date ring (white
arrow), the center wheel pivot (red arrow), and the
pallet lever bridge (green arrow). The very elegant dial
retaining screw is indicated at the orange arrow. (The dial
foot–a pin soldered to the back of the dial–is inserted into the
plate hole to the right of the screw and held by the screw. A second
dial foot is secured with the same arrangement 180 degrees opposite
on the plate.)

The keyless works parts, numbered as in the illustration
above, are shown removed from the movement in Figure 1, at
right. The screwdriver blade tip (blue arrow) is one millimeter
in width, and provides a sense of scale,
as well as an appreciation for the very fine finish of the parts in
this IWC caliber. (The Bergeon anti-magnetic screw driver is of very
high quality, though it reveals a relatively rough finish in comparison
to the keyless work parts.) It should also be mentioned that the Jaeger
LeCoultre design of this keyless works in particularly refined and sturdy.
In the disassembled illustration, the pull-out piece (2) is shown
inverted, revealing three pins. The pin at 2B is the detent
pin that rests in the stem groove at 1B. It is by this connection
that the entire mechanism switches between winding and setting functions.
(The lower left pin carries the pull-out piece check spring 3,
the upper left operates the date setting mechanism, which will not be
discussed here.) The other indicated positions on the stem indicate
the pivot (1D), which supports the stem by resting
in a hole in the movement plate; the square section (1C),
which lies within the square center of the castle wheel and thus rotates
the castle wheel (4) when the crown is turned; and the threadedsection
(1A, which allows the crown to be screwed onto the stem). The
stem is illustrated in more detail at left in Figure 2. The square
section (1C), pull-out piece groove (1B), and threaded
section for the crown (1A) are indicated. The pull-out piece,
itself, is shown in profile on top of the stem (2), along with
its pin (2B) engaged in the stem groove.

The
castle wheel and crown wheel are shown in detail at right. The castle
wheel (1) carries conventional teeth on one end (2) to
engage with the intermediate wheel that sets the hands. On the
other end (3) the castle wheel carries Breguet teeth that engage
the Breguet teeth (4) of the crown wheel. The peripheral teeth
of the crown wheel engage the transmission wheel that winds the
main spring.

HOW THE KEYLESS WORKS WINDS

Figure
3 shows the keyless works of the caliber 887 in the winding position.
The stem is pushed in (up, in the illustration), the stem groove has
rotated the pull-piece (2) counter-clockwise on its screw (2A).
Thus the upper tip of the pull piece (blue arrow) allows the
castle wheel lever (5) to move down so that the castle wheel
(4) is connected to the crown gear (4A) at the red
arrow. The castle wheel lever is held in this position (at the green
arrow) by the stop lever (7) which cleverly doubles as a
spring. The same positioning of the mechanism is shown in an Omega caliber
351, in “Cannon pinion, wind position.”>Figure 4. The castle wheel
(4) is connected to the crown gear (4A) at the green
arrow, and disconnected from the intermediate wheel at the red
arrow. The crown gear, via a transmission wheel (not illustrated),
winds the ratchet wheel attached to the mainspring barrel arbor
(or center shaft). When the mainspring is wound, the ratchet wheel and
arbor turn, but the barrel itself does not. In some movements, such
as the caliber 887, there are a series of transmission wheels instead
of a single wheel. The 887 uses three, attached to the underside of
the barrel bridge rather than to the plate.

HOW THE KEYLESS WORK SETS

The setting function of the keyless works is illustrated
in Figure 5. The red arrows indicated the direction and
sequence of movement as
the crown and stem are pulled out (1). The pull-out piece check
spring (2) allows the pull piece to rotate clockwise (3)
by allowing the upper pin to slide under it (at green arrow).
The upper tip of the pull-out piece contacts the castle wheel lever
and pushes it up (4), which slides the castle wheel (blue
arrow) along the square section of the stem (5). The top
of the castle wheel is now engaged with the intermediate wheel (and
disengaged from the crown gear). “Motion works, caliber 351″> Via the minute wheel and hour
wheel (shown right), the intermediate wheel (blue arrow)
rotates the hands of the watch. As can be seen in Figure 5 (above)
at the yellow arrow, and 6, 7, and 8, the
hack mechanism is brought to bear on the balance wheel and stops the
watch. It is the upper curved section of the stop lever (orange arrow)
that contacts the balance.

The setting position is also illustrated in the caliber
351 in Figure 6.
The castle wheel lever (5) has slid the castle wheel along the
stem to the left. The engagement of the castle wheel with the intermediate
wheel is shown at the green arrow. As seen at the red arrow,
the castle wheel is disengaged from the crown gear (4A).
The minute wheel, engaged with the intermediate wheel, is just visible
in the lower left corner of the photograph.

HOW TO USE AND CARE FOR THE KEYLESS WORKS

Because
the keyless works is the one part of the mechanism that is operated
by the owner, it is the system most subject to abuse. Unlike most of
the rest of a watch movement, it is of relatively robust construction,
and is usually lubricated with light grease (rather than very light
oil). All operations of the crown should be light and smooth,
and without undue force. The need to use undue force suggests there
is a problem that should be corrected. A lack of lubrication in the
keyless works can quickly wear parts, particularly in the watch that
is often hand wound or reset.

As for the rest of the operation, let your knowledge
of the mechanism be your guide.

1. The stem is designed for rotational forces, not
lateral ones, so do not put side pressure on the crown. This usually
means removing the watch from your wrist to wind or set it. Lateral
forces create wear (sometimes in the movement plate itself) and will
eventually
break the stem at the pull-piece groove.

2. When moving the crown from one position to another,
the castle wheel (clutch) is disengaging from the crown gear and engaging
with the intermediate wheel, or vice versa. Allow the crown to rotate
as you move it to facilitate the engagement. When you pull the crown
into the hand setting position and the hands jump, this is because the
castle wheel was not aligned with the intermediate wheel and the latter
had to jump into position. When pushing the crown in, use the ball of
the finger (rather than gripping it) so that it can rotate on its own
if necessary. Slight, gentle, deliberate rotation of the crown
when changing its position can facilitate engagement.

3. Winding can be done forward only, or back and forth.
The backward motion does nothing but ratchet the castle wheel over the
crown wheel, to no utility. Because this produces some wear, I normally
wind forwards only; but I give a full backwards turn at the end to spread
lubrication over the Breguet teeth and to relieve any possible winding
tension remaining because of a sticky or damaged barrel click.

4. High friction at the cannon pinion (see the accompanying
article, The Motion Works) can cause the movement to over bank
or knock during forward hand setting. This is largely mitigated by brisk
short advances of the time rather than slow, sustained advances. Hands
can be set backwards or forwards, but calendar switching periods (and
the engagement of other complications, like moon phase) must be observed.
Know your watch is this regard!

5. In resetting calendar mechanisms and other complications
operated by the crown, do so slowly. Such mechanisms are not
made for high-speed operations, and you can develop considerable rotational
speed twirling a crown between forefinger and thumb.