|
Finish perpetual calendar. Begin tellurion assembly - July 2015 This month we finish up the few remaining details to complete the perpetual calendar before moving on to the tellurion.
These photos show some of
the final fabrication stages for the calendar module. The wheel cocks and
movement pillars are cut and decorated.
A few more small housekeeping chores. Here Buchanan installs the manual
adjustment knob for the digital year counter.
The circled area shows the connecting rod from the knurl knob to a
gear that adjusts the counter. Note the small decorative spur on the frame
as well as the pillar opposite aligns perfectly to allow that long rod to connect
to the counter and be supported on the opposite end. This demonstrates one
of the hundreds of micro planning decisions needed to make this machine work
well.
The first photo shows a close up of the adjustment knob. Next the tiny knob being turned. The center counter-rotating dial below within the main time dial is still a paper mockup and has become somewhat soiled while the remaining dial work is in the final enamel material.
The first three photos
show the fabrication of the manual ‘finger levers’ that the operator uses to
disengage the individual detents for each dial readout, thus allowing for
their adjustment. The fourth photo shows a tiny stop lever which is fitted
to each of the detents, circled area. These will prevent the levers from
flopping out of position in the event the calendar module is removed and
turned upside down. In this manner everything stays in place preventing
accidental derangement in repair or the reassembly which will be necessary
when the machine is shipped from Australia to the United States. Below
are a series of photos showing the internal structure of the calendar
assembly.
The first pair of
photos encompasses two dials of the calendar assembly. These are the day and
date readouts. The day readout is the simplest of the calendar. Monday
through Sunday is a seven day cycle that remains constant throughout the
year regardless of the other complications to account for the variances in
February or the leap year cycles. The date is an entirely different matter
and the date readout is connected to the calendar calculator module that
determines the number of days February should have in any given year. This
module accounts for not only the quadrennial leap year, but the 100 and 400
year exceptions to the February rule; making this a third-order calculator
that is good in perpetuity. It is also fully reversible. So any of the
calculations needed to keep the calendar accurate going forward is
remembered after the calculator is run in reverse. This was not an easy
task.
The next pair of photos
shows the month calculation. The month trip is controlled by the calculator
module so February is tripped at the right time according to the perpetual
rules. The circled area is the detection detent for the month. This is
tripped on a regular basis but for February the number of days is determined
by the calculator.
The third set of photos
concerns the leap year dial and the year counter. The year calculation is
the most complex since it is dependent on the date and month calculations as
determined by the calendar calculator and the month readouts as well as the
quadrennial leap year. From these examples one
can see the hierarchy in the complexity for determining the calendar
readouts. The simplest is the day, unvarying throughout the year, there are
no adjustments here. Next is the date which is inextricably connected to the
February cycle and requires the use of the calendar calculator module. Next
is the leap year which is determined by the calculator module to give it
perpetuity. And finally the year counter which only will turn over after all
of the prior conditions for the signal of the year is given based on all of
the prior data sets being met.
|
The video shows the perpetual calendar. This is a completely self-contained unit encompassing over 580 parts. The calendar is a third-order variety, taking into account leap years as well as the 100 year and 400 year exceptions to that cycle making this perpetual in perpetuity. The machine remembers the calculations needed for this ability in both forward and reverse. We believe this reversibility has never been done before in a the context of a mechanical timekeeper.
---------------------------------------------------------------------------------oOo-----------------------------------------------------------------------------
Now begins the fabrication of the tellurion complication
The
model we are using for the tellurion was made by Mathias Hahn and is described in
Astronomische Uhren und Welt-Modelle der Preistermechniker im 18. Jahrhundert,
Luwig Oechslin. This is a two volume set of German-language books that contain
the descriptions of many of the world’s famous astronomical clocks and orrerys
located in Germany. There were several examples of Hahn’s work. The most
important part of this publication is the attached set of folios that show the
schematics of each item described. We chose a hand-cranked telluriom as well as
a grand orrery, both by Hahn for our components. The tellurion dates from 1780
and is in the Lindengut Museum, Winterthur, Germany. This saved countless hours
of design time if we had to design these from scratch and is another example of
our borrowing what we consider to be good ideas from the past masters in the
horological field. These were chosen at the earliest stages of the project, even before
the original wood mockup was created in 2006.
On the drafting board Buchanan begins the preliminary design work. The photo on the upper left hand corner is a photo of the Hahn tellurion from the German language book. The schematic to this tellurion is in the right hand corner and comes from the same source. The center drawing is Buchanan's interpretation of this and the large diagram below is the initial scale fabrication diagram.
The photo and two diagrams are what is seen on the drafting board. Note that we have added to Hahn's design by including the inner planets of Mercury and Venus. Buchanan states "This is the first version of the tellurion, my interpretation of the Hahn to understand it and to see if we could include Mercury and Venus. I took the Pouvillon ratios from his tellurion. Now I must see if it is physically possible". Here Buchanan draws from his experience in the restoration of the Pouvillon astronomical clock he had accomplished in 2012. Pouvillon's interpretation of his tellurian was magnificent.
The first drawing shows diagrammatically all of
the necessary components to get an idea of how deep this assembly must be. It
shows that the Earth will be about 1/8 inch (less than 0.5 cm from the front
case glass.
This is a bit too close, but Buchanan indicated that the glass case can be moved
forward a bit. The issue we have is not so much that we cannot make the case
deeper, but that we do not want the front surface of the glass too far in front
of the rest of the clock mechanism; making close inspection of the remaining
movement more difficult.
The first drawing shows the over-sized idler wheels. Next several alternative sizes superimposed. This also has a side elevation represented above.
The revised idler wheels are now finalized and this gives the tellurium a slimmer profile.
The first drawing depicts the central cannon tube nest. Notice the use of ball bearings which replace the conventional nested cannon tubes. One must remember that this assembly in reality is rotated ninety degrees from the drawing shown. If a conventional set of nested tubes were to be employed here, the friction would be impossible to overcome. Here is a good example of where modern design and materials make possible what would otherwise be impractical. Next color coding is added to the diagramed tellurium wheel assembly. This has been carried through the previous few drawings as well. Red = Mercury, Yellow = Venus, Green = Earth, Black = Moon, Blue = main input drive to tellurium. Not all color coded wheels of a particular color are all adjacent to each other, but may be located elsewhere and working through other wheels to their final destination.
The wheel blanks are now ready for fabrication.
If we were using modern CNC methods the data on the sheet would have been
inputted into a computer and the wheels automatically cut out. But here Deryck
scribes out each wheel by hand, as was done for centuries by the old masters of
horology and will cut them out each by hand on the jeweler’s piercing saw in the
same hand-made manner as hundreds of wheels before in this project.
