The principle of the gearing is that moving the Butterfly ramps ‘1’ position will cause each pin in the chain wheel segments to be depressed whilst pushing the segment in the chosen direction by ‘1’ position. A full rotation of the crank changes gear. Any gear position may be selected and will be achieved in one rotation of the crank.
The indexing is important as this effects the chain length in multiples of one link.
Several engineering techniques were required to achieve this item. They included Cad Design, Turning, Milling, Welding and Laminating Stainless Steel.
New technologies (subject to funds) mean that the shedders are looking at ‘3D printing’ to mix materials and reduce the weight in combination with Arduino control to simplify gear changing.
Early prototype with four chain expanders.
T.A. Crankset (stock) which expanding chain wheel fits.
Second generation - using five expanding segments.
.The working part - The pins on each segment are depressed to allow movement.
The early actuator assembly with indexed positions on the control bar.
Click on icon to hear how the chainwheel works