About this 3D model

This object can be attached to a wheelchair to power it by rowing motion. It was inspired on the open source design publised on https://hackaday.io/project/7221-hand-drive . It's very similar, but my design doesn't have the gears parts (I try to made it simpler)The design is only for forward, but it has the gear tooth for backward motion (a system withcables must be built, like the original Hand Drive) This object was made for the "Mutual de Seguridad C.Ch.C" from Chile. In a project of the Direction of innovation and development, and the Neuro rehabilitation institute.