I am indebted to a commenter on yesterday’s skeletonics post for reminding me of G. John Dick and Eric A. Edwards’ SpringWalker spring-assisted lower-body exoskeleton. Using the slightly half-baked terms I proposed yesterday, the SpringWalker is another notable example of a “passive” exoskeleton, i.e. one that amplifies the speed and range of a motion, but does not actually add power. An oldie but a goodie, the SpringWalker was patented back in 1991, when the term of a US patent was still 17 years, and is thus now out of patent. [Thanks, DanYHKim!]