Bjorn.B.Setterberg posted to the ICEBIKE list that he had seen a
"Real" ICEBIKE at a Farmers Museum" in the town of Havdhem on the
Island of Gotland just west of the Swedish coast in the Baltic.
Gotland is a popular cycling destination, being mostly flat and rich with history.
The largest city is Visby on the eastern edge of the island. Frequent ferry service
to the Swedish mainland is provided.
As Bjorn described the ICEBIKE:
"Instead of wheels it had a front skate that you could steer with ordinary
steering handles, and at the rear it had also a skate, inside which there was a moving
skate that went forwards and backwards as you pedaled it via a chain.
It was used for transportation on frozen lakes."
Bjorn was kind enough to take photos of the bike and scan them for the ICEBIKE
site.
The first photo shows the Iscykel from the front, showing the front skate, or runner,
which appears to be made of iron clad wood. This appears to be loosely coupled to
the back runner (detail largely lost in the photo at right), in such a way as to allow the
front skate to turn, and at the same time to force the rear skate to follow without
inducing stress in the frame.
The front suspension consists of a light wooden "Crutch" like structure which
bolts into the existing front fork.
This required fabricating only one part to attach to the front runner. The existing
handlebars and steering mechanism remain in place.
Even more interesting than the front structure is the drive mechanism. The rear
runner has slot in the center running longitudinally. In this slot there appear to
be two independent drive skates or claws that slide fore and aft. These are driven
by a linkage system not dissimilar to that found on old railroad steam engines.
The difference is that these linkages are designed to operate at a mechanical
disadvantage with regard to power so that they have a Long and Fast
"stride".
Careful study of the linkage reveals that the builder replicated the structure of a
human speed skater. You can see the mechanical equivalent of the thighs and lower
leg, the knees, the hips, etc.
The most noticeable difference being that one knee appears to bend backward so that the
one of the skates may be placed ahead of the other rather than having them run beside each
other. The power strokes are opposed so that there is always one skate in the power
stroke (moving rearward) while the other is in recovery (moving forward). This, I
speculate, provides easier mounting and less friction.
Compare the above photo to the one below. Note the different position of the
"legs", the leg that is stretched forward in the top photo is as fully to the
rear in the second image, on what appears to be 1/8 turn of the crank.
Spelling in photo is IS CYKEL, but Gunnar
Hovmark of Sweden says that ISCYKEL is proper.
Bjorn was not able to provide shots of the other side of the gear train, so one can
only speculate that the "thighs" are driven by a linkage (visible in the photo
above just to the rear of the cog set) which in turn are driven (I'm speculating here) by
a cam arrangement just inboard of the cog-set on axle.
Although there appear to be multiple cogs on the rear cluster, there is no
derailleur, so
without dismounting and adjusting the chain, it would appear to be a fixed gear
arrangement. One wonders what purpose the frame pump would serve on this device. In
fact, one wonders about the practicality of the design in general, after all, Bjorn
only saw ONE.
Home of the Winter Cyclist