seatpost hitch

roll6 052

Originally uploaded by aaronforest.

This is the hitch I designed for the BEN ambulances. I will also use this design for my new trailer design, “Chariot”, which is built with the design principles that guide my community bike cart design project and the designs “Deep and Short” and “Flatsy”. Low cost in parts, can be fabricated with minimal experience and simple tools, etc–but this design pulls under the seat on the bicycle for operation as a hand cart as well. The BEN Namibia trailer that I am designing is based on similar technolog, but uses kink bends reinforced with 10mm rod to eliminate the need for a 25mm tubing bender, as conduit bender for 25mm OD tube aren’t strong enough to bend 25 X 1.6mm tubing, nor are they available in Namibia, nor is the radius small enough.

This hitch attaches to a bicycle seatpost (left side of photo), has a hitch pin that slides through the trailer pivot tube to allow easy removal, and a universal joint made from nuts and bolts. I am redesigning two of the pivots to spin freely, instead of on threaded surfaces, which introduce the potential for binding and unsafe operation.