The White Oak Martial
Arts Center Sprung Floor Concept
By Dan Sharp Sensei
Simple, really! Our floor design comes from some "homework"
I had to do during my youth as a master cabnetmaker's apprentice (back
when I thought I could grow up and work for a living doing something I
*liked*. How naive...). It's based on the suspension system of the medieval
sleigh used in the Scandianavian countries, where metal was scarce, but
wood was relatively plentiful, the "spring" was nothing more
than a wooden "beam" supported at the ends. The spring of the
system was derived from the natural flex of the wood, and controlled by
the distance of the supports. Move the end supports closer together, and
the "spring" became more rigid; further apart, the spring became
softer.
Below is a (very crude - this is *not* a freehand drawing
package!) sketch illustrating this concept:
Those of you that are familiar with older cars, probably
remember the leaf springs used on the rear wheel suspension. Guess where
*that* bright idea came from...
With this general concept in mind, we built individual 4X8 foot
floor sections, and strategically located "springs" such that
the floor could be "adjusted" where each section met another
by varying the distance that separated the blocks supporting the "leaf"
board. We covered the floor with a material called Rubatex that can be
ordered in varying "hardness". We found that we needed only 1/2
to 3/4 inch Rubatex - the floor provided ample spring, so we needed only
enough to take the "edge" off the fall. We originally considered
fastening each of the floor sections together, but found that the weight
of the Rubatex was such that the sections had *no* inclination to move!
We covered the entire floor with a single sheet of canvas laced
and drawn at the edges in a traditional manner.
Below are a couple of detail sketches of the floor system
concept:
This view from the top illustrates an example placement of the "springs"
under the floor panels:
This is the method we applied in constructing our floor, and frankly,
it's turned out to be one of the best I've ever trained on (gratuitous
pat on the back here...). This *is not* the exact construction spec though
- since we had the luxury of a high ceiling, we also built 3 6X32 foot
frames out 2X12s for our 24X32 foot floor as a layer between the "springs"
and the 4X8' floor sections. This allowed us to get a more even spring
to the floor, and use fewer springs, thus requiring less adjustment and
leveling of individual sections. If you're an enterprising individual (or
have access to one), what I've published here should be enough to get you
started. If you really would like a set of detail plans for the floor panels,
intermediate frames, and the "springs", I would be happy to provide
those for $15 dollars a set; just email me and I'll give you info on where
to send a check or money order for the plans. Delivery in about two to
three weeks (depending of our reliable U.S. mail...).
dansharp@email.com