University of Sussex
Product Design Show 2012
The Amex Stadium: 06 June - 09 June
New Designers, London: 04 - 06 July
The Myers Extension Mechanism
David Myers

An anti-buckling and power providing mechanism for above knee prosthetics.

The Myers Extension mechanism is a simple, cost effective modification for above knee prosthetic legs intended for use in the developing world. It consists of four easily fabricated parts that can be retrofitted to almost any existing prosthetic design. It prevents the existing prosthetic knee unit from buckling unintentionally during regular walking, when traversing inclines or when ascending stairs. It also allows physically fitter and stronger amputees to ascend stairs one foot at a time or "step over step" as an able bodied person would as opposed to the usual amputee behaviour of dragging the prosthetic leg behind as the stairs are ascended, relying entirely on the existing leg.

The mechanism consists of a flexible rubber member which is customised to the user's weight and height and acts as a linear spring storing and returning the potential energy of the user's body weight to the user's motion. The other components include a loading support at the prosthetic ankle, a transverse bar suspended behind the knee unit and a loading point embedded in the prosthesis socket which also serves to keep the rubber member in place and allow the prosthetic a degree of passive flexion when the added stability and force of the rubber member are not needed.