Please read the following description of an attachable hand-cycle device that attaches to a wheelchair.
The proposed device is able to attach to any existing wheelchair (with no extra parts required) and transform the wheelchair into a hand-cycle. There are two components to the device, the hand-cycle component and the component that it attaches to. Instead of using the same concept of attaching the hand-cycle component directly to the wheelchair as existing attachable hand-cycle devices do, we have designed it so that the hand-cycle device attaches to a separate component that is strapped down to the seat of the wheelchair. This allows the device to attach to any wheelchair instead of only select wheelchair models. The component that straps down to the wheelchair seat is designed to act as an extra seat cushion for the wheelchair user (while functioning as the docking station for the hand-cycle component) and can always be left on the chair, even when the hand-cycle device is not attached. The hand-cycle device easily attaches to the extra seat component through a dock, twist, and lock mechanism that ultimately lifts the front wheelchair casters off the ground. This transforms the wheelchair into a hand-cycle, making it much easier and faster to travel outdoors, while putting less strain on the muscles.
We are a socially minded business that will manufacture the hand-cycles for distribution in the U.S. out of light weight aluminum. For every hand-cycle we sell in the U.S., we will manufacture 2 bamboo handcycles in Kenya, Africa and donate them to Kenyans in need. We can do this because we use a cost-efficient manufacturing method in developing countries where we fabricate the hand-cycles out of bamboo and used bicycle parts. We are well set up to do this and we already have manufacturing partners located in Kenya.
The hand-cycle you see in the figure is the one designed for developing countries. The U.S. model will look very similar, but made out of light weight aluminum and have a more sophisticated locking mechanism for the dock.