Jonathan Tippett has built a 1,8 m tall leg, a multi-hinged structure of welded tubular steel, fitted with hydraulic rams, dampers and air springs – all articulated like the hindquarters of a dog.
It is permanently attached to a flatbed trailer by a 1,8 m-high pivoting tower, which itself is tethered to the trailer by four heavy-duty nylon straps. Hydraulic lines extend out from the leg to a control seat on the ground next to the trailer. That seat, which Tippet calls the Exo-Frame, is built around a repurposed unicycle saddle. It has a five-point harness and an articulated metal cuff that secures to the user’s forearm with an inflatable air bladder.
The idea behind the machine is human amplification. A user is supposed to power up the whole thing, strap himself into the Exo-Frame and lock into the cuff. Tippett and his team of volunteers designed their 1 297 kg leg to respond directly to the user’s arm movements. It can move up and down, even jump up into the air, amplifying the force applied by the user by a factor of 100.
Tippett calls his creation the Alpha Leg, because it is essentially a prototype and testing platform for the machine he really wants to build: a giant, four-legged, human-controlled walking exoskeleton named Prosthesis.
This video shows the ins and outs of the Alpha Leg…
Tippett’s Alpha Leg was recognised in PM’s Backyard Genius Awards 2013. Get your hands on our October 2013 issue – on sale 23 September – to meet more backyard geniuses with unconventional, slightly irrational but utterly awesome, creative inventions.