Design Updates to Tensegrity Blocks

[Spencer W Hunter]

ref.: http://www.u.arizona.edu/~shunter/tblock.html

Design Updates to Tensegrity Blocks

Spencer Hunter, 2005

I am placing any unique features mentioned here into the public domain.

7/23/2005

Inspired by Tim Tyler's compression rings, I posted to the newsgroup
bit.listserv.geodesic that one of his rings could be almost half
tendons and self-deployable.  In his illustration linked from the
Tensegrity Blocks directory, only the purple struts need to be struts,
and the remaining green and white struts can be tendons; with the
vertical tendons acting as tensioning agents.

The basic unit is similar to my tensegrity block.  It is an
octahedron consisting of eight hinged struts and a square equator of
tendons.  A tensioning tendon running down the middle of the
octahedron forces the structure into rigidity.

Although I mention that the best approach for deploying these
structures might be to develop a powered micro-winch for the pull
wires, I have conceived a more low-tech technique.  As with my
tensegrity blocks, zigzag-strut tensegrity dome, and the
above-mentioned octahedron, the tensioning tendons can be elastics
that allow the structures to be collapsed and stowed.  Riding along
with, and perhaps lashed to, each elastic tendon is an inelastic
high-tensile rod capable of briefly sustaining minor compressive loads
during deployment.  A disc screwed onto one end of each rod enables it
to compress a hinge.  A cone is screwed onto the other end, and during
deployment, this cone will penetrate a cylindrical trap that prevents
the rod from moving backwards.  The cylindrical trap is connected to
the opposite hinge and is able to compress it.  The configuration of
the trap can vary, but it acts in the manner similar to that of a
Chinese finger trap.  If the midsections of the traps are flexible,
they can be individually compressed if need be to release the cones
and enable the entire structure to be collapsed again.  I presently
envision the trap to be as simple as a tube with a slotted plastic
end, and once the cone penetrates, the plastic triangles snap in
behind the cone and trap it.

Spencer Hunter, Tucson, AZ
gopher://www.u.arizona.edu:80/hGET%20/%7Eshunter