Isometric view of hand-cycle design with user.
Dimensions of the proposed hand-cycle in inches.
The pedaling mechanism used for this design was developed by a team at the University of Wisconsin-Madison, under the direction of Dr. Frank J. Fronczak.
This pedaling mechanism design allows the rider to use larger muscle groups to pedal, permitting longer periods of use with more efficient energy expenditure.
The wheel configuration of the Wisconsin-Madison design had a large turning radius, which limits the mobility of the user.
I wanted to maximize the usability of the hand-cycle. In order to achieve this, I proposed the configuration shown here, which dramatically reduces the turning radius of the vehicle.
The frame for the hand-cycle was designed from commercially available Al 6061-T6 tubing.
FEA was used to verify the integrity of the frame design.
Steering is achieved using hydraulic actuators. These are moved using a swivel mechanism at the hand interface.
Actuators mounted at the steering column apply the force that is input at the hand controls.
A rear transmission was designed to allow independent wheel engagement, and inversion of the freewheel mechanisms. This was hydraulically operated as well.
Detail view of freewheel engagement mechanism.
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Hand-Cycle Design

I designed this hand-cycle for my undergraduate senior design project at the University of Costa Rica. The goal of this project was to propose an alternative hand-cycle design that allows for a more efficient and functional user experience, emphasizing the mechanical considerations of the design.

Santiago A. Morales...
Mechanical Engineer Santa Cruz, CA