This desk-clamped paper holder was designed as something I would find useful in my own work environment. It takes virtually no space on the desk itself, and adds an additional handy storage area.
One of the design challenges was to create a mechanism that would ensure the stability while enabling it to get firmly attached to a surface of any width. In order to ensure that, the red holders are fixed to the axis via three small detachable lockers, while the clamps can move in only one direction.
Another challenge was to make sure it can be easily printed. To achieve this, each part is designed with no overhangs to maximize the printing precision, and can be printed separately then assembled afterwards. This also ensures easy packaging and transportation.
While it was envisioned as a desk paper holder, it can be used in multiple situations, from kitchens to bathrooms, living room shelves to garage tool-tables.
see the mechanism in action: http://i.imgur.com/QCzLfWk.gif