Initial drawings from fabricator
In April of 2004, while the fabricator was working on my friend's commission, a few
preliminary design idea drawings were prepared using some of my suggestions. Maintaining
power was to use what I consider to be the best type which is the planetary gear system,
rather than the more common Harrison spring types. Notice the planet gears are turned 90
degrees to make the effect more interesting rather than on the same plane as is normally
done. This design was later adopted, and all four main wheels will be equipped with system
even though it was only necessary to do this on the going and celestial trains. The second
drawing is the anti-friction wheel system which was also eventually adopted to support the
two H1-type balances. The design is reversed from what one would normally expect. The
balance arbors do not rotate between the wheels. Instead the wheels within the
cage are fixed to the balances and this entire assembly moves back and forth on a
fixed arbor.
Below is a view of the anti-friction cages as they would support the balances. At this
point the fabricator had chosen a more modernistic design for these. Later this was
changed to more conform with Harrison's original look. Next is a concept for the
remontoire flies that we call a compound fly. The internally toothed ring will allow for a
fly to not only turn but also pirouette around each other. Later we went with a
four-bladed design for each of the two remontoire flies. The strike train flies are based
on a design by Fasoldt that also pirouettes.
Below is an initial concept for the frame. Again this is at the time I was still
thinking in terms of a tower clock designs. This was later abandoned in favor of a more
conventional pillar and plate configuration. The center structure is for the remontoire
and this was later flipped upside-down as is commonly seen in clocks that use this type of
swinging frame remontoire.
Later in January 2006 a second set of drawings was made in preparation for the creation
of a working model of the escapement and remontoire in plastic. This working mockup was
necessary as such a system had never been made before. By this time the fabricator had
finished his earlier commission for my friend and was now working on this project as well
as a smaller commission from me.
The first picture shows the concept for the dual, counter-rotating escape wheels
designed to give a kaleidoscope effect between the swirled spokes of the wheels as they
would appear superimposed upon each other. (a
video
of a the operating plastic mockup shows this effect). This was an idea contributed by the
fabricator and it's significance caused me to change the design to have the escape wheels
in front of the clock as opposed to the rear. The second diagram shows the concept of the
dual remontoire being driven by a differential system (as designated by the box gear
system labeled 'I'). Each of the two remontoire drive one of the H1-type
balances. In turn each of these balances drive one of the two escape wheels. What keeps
the system in synch is the fact that that as in Harrison's original design, the two
balances are mechanically slaved together.
This drawing shows a novel way of getting a bit more drop from a limited fall. To the
best of my knowledge this type of compound barrel was only used once before in a Martin
Burgess' design for a sculptural clock and was adopted in the final design. See the mockup.