Patent ID: 8211106

Claim:
An external bone distractor ( 1 ) comprising: a curvilinear rod ( 4 ) comprising a plurality of diametrically opposed flat sections ( 7 , 8 ), at least two carriages ( 2 ) engaging on said rod ( 4 ) and solidly attached to pin supports ( 3 ), guide means ( 10 , 13 ) which co-operate with said flat sections ( 7 , 8 ) for preventing rotation of each of said carriages ( 2 ) around the axis, of said rod ( 4 ), means ( 14 , 15 ) for adjusting the position of each of said carriages ( 2 ) along said rod ( 4 ), characterised in that said curvilinear rod is provided with threading ( 9 ) extending solely on upper and lower surfaces of said rod along neutral fibres extending along longitudinal bands located on upper and lower surfaces of said rod, and said bands extend solely in the vicinity of said neutral fibres of said rod ( 4 ).