The reason for no drive train is that if you have no pedals not any cranks
and no chain or shaft or chain or any other such then no need for a drive.
This is a Laufmachine like the Draisine made by Karl Von Drais mid 1850 or so.
Caster wheel mention in the patent is most likely of this sort
http://en.wikipedia.org/wiki/Caster_wheel
Casters may be fixed to roll along a straight line path, or mounted on a
pivot such that the wheel will automatically align itself to the direction of travel.
[h=3]Rigid casters[/h] A basic, rigid caster consists of a wheel mounted to a stationary fork. The orientation of the fork, which is fixed relative to the vehicle, is determined when the caster is mounted to the vehicle. An example of this is the wheels found at the rear of a shopping cart in North America. Rigid casters tend to restrict vehicle motion so that the vehicle travels along a straight line.
I am no mechanic but if you mount a pivoted caster wheel
in the end on machine that is supposed to help Elders
to keep balance then you are in for big trouble.
So I trust that the writers of the patent refers to a rigid caster wheel.
Maybe when one buy them they are referred to as caster wheels
regardless of if they are swivel or rigid? Some four wheel Carts
at Shopping Malls in USA has the front casters to swivel while the
rear caster don't swivel so that can explain why they use such
misleading name convention.
The rest of the bike looks very much Strida to me.