Figure 21 comprises illustrations of five other designs of folding bicycles. These are identified as (a), (b), (c), (d) and (e). The Faun design (a) comprises three drawings of the style used in 19th century books and so looks like the oldest design. The side view shows that the Faun has the same layout as a conventional lady's bicycle, complete with a strengthened lower frame in lieu of a cross bar and normal sized cycle wheels. A hinge is clearly evident in the lower frame just in front of the chain-wheel. The handle bars are also hinged so that they can be folded down. The folded assemble looks as if the main aim is to save space rather than to be easily carried. The Airframe (b) comprises two side-view photographs of the bicycle, first in normal configuration and then in the folded state. The cycle wheels are small like the Bickerton. The frame is the normal diamond construction which will be explained in Figure 28a but it appears to be pin jointed rather than the normal fixed (welded) structure. There are locking struts which when released will allow the frame to be collapsed. In the folded state it is clear that the bicycle frame has also been folded but no hinge is evident in the photograph. The Peterson (c) comprises a single photograph of the bicycle. The frame looks like a conventional diamond configuration except that the seat is suspended between the handlebar pillar and an extension of a strut in the rear part of the frame. It is not evident from the photograph how the bicycle folds. The Dahon (d) comprises two photographs of the bicycle, first in folded state and then in normal configuration. The design looks like a Brompton but folds like the Bickerton. The frame is based on an almost horizontal beam that is folded just in front of the gear wheel. In the folded state, the seat strut slides through the frame and the handlebars fold down between the two cycle wheels. Like the Bickerton, the chain wheel and pedals are exposed to the person carrying the folded bicycle. The Trusty (e) comprises a single photograph of the bicycle in its unfolded state. The design looks like a Brompton but folds like the Bickerton. The frame is based on an almost horizontal beam that is folded just in front of the gear wheel. To achieve a compact folded state, there are quick release mechanisms that enable the seat and handlebars to be collapsed into the folded bicycle. Like the Bickerton, the chain wheel and pedals are exposed to the person carrying the folded bicycle. To summarise, four of the five examples use the same mechanism of folding as the Bickerton. They have an almost horizontal beam connecting the front and rear halves of the bicycle that has a hinge just in front of the chain wheel. The other two attempt to retain the diamond frame configuration of the conventional bicycle.

 2.2 Folding bicycles