Cardboard has long been proven a very flexible material, used to create products as wide-ranging as bicycles, helmets, buildings, and even a car. Join us now, as we celebrate the most innovative uses of the material that we've come across in recent years.

Some of the designs below have been manufactured as a product which you can purchase right now, while others remain a concept (and are likely to stay that way). All display an innovative use of a material often considered worthy only for the trash.

Cardboard bicycle

Israeli inventor and entrepreneur Izhar Gafni invented a working cardboard bicycle prototype that's constructed mostly from recycled cardboard, and promises to cost relatively little to manufacture. The bike weighs around 9 kg (20 lb), and incorporates unwanted car parts such as tires and a timing belt in the assembly.

Despite its being constructed from cardboard, Gafni states that his creation will be perfectly sturdy and water-resistant, and it is rated to support a rider of up to 220 kg (485 lb).

We've no word on a release date for the cardboard bicycle.

Kranium helmet

If you're going to ride around on a cardboard bicycle, then perhaps it makes sense to go all out and wear a Kranium cardboard helmet, too.

While on first glance, donning a cardboard-based bike helmet may appear borderline insane, Royal College of Art student Anirudha Surabhi tells us that thanks to its unique honeycomb structure, the Kranium can absorb up to three times the impact energy of a standard helmet during a collision while remaining 15 percent lighter.

The Kranium is available in the UK now and will set you back £79.99 (US$129).

Cardborigami shelter

Los Angeles-based designer Tina Hovsepian started the Carborigami project in a bid to help mitigate some of the effects of homelessness by producing an improved temporary shelter. Drawing inspiration from the Japanese art of origami paper-folding, the shelter comes in two iterations: a large unit for several people, and a smaller single-person unit.

The Cardborigami shelter is finished with a fire-retardant and water-resistant coating, and folds for easier movement. In addition to the shelter, the designer also plans to set up an outreach center to help the homeless move into more suitable accommodation.

Yakushima Takatsuka Lodge

No list of cardboard innovations would be complete without giving mention to Japanese architect Shigeru Ban, an architect best known for his work producing structures which are made – at least in part – from recycled cardboard and paper tubes.

In addition to the Christchurch Cathedral, Ban has produced a working footbridge, log cabin, and a number of other structures from paper and cardboard over the years. On a more modest note, but still in keeping with Ban's understated style, is the recently competed Yakushima Takatsuka Lodge: a mountain hut built on Japan's Yakushima Island. The hut's paper tubes serve a practical purpose by enabling natural light to filter into the hut, and they can be easily replaced when necessary.

KNÄPPA digital camera

Purveyor of affordable furniture IKEA knows a thing or two about using cardboard packaging, but one doesn't generally associate the furniture chain with digital photography. Well, in 2012, IKEA announced that it would be giving away the KNÄPPA cardboard digital camera to promote a furniture collection.

The KNÄPPA is powered by two AA batteries, packs a 2.3-megapixel sensor and measures 105 × 65 mm (4.13 x 2.56 in), but alas is yet to appear in IKEA stores.

Vax vacuum cleaner

Billed as the world's first cardboard-based vacuum cleaner (presumably there can't be too many others), the Vax ev prototype was created by industrial design student Jake Tyler while he was on a student placement at vacuum cleaner company Vax.

Naturally, the Vax ev isn't manufactured solely from cardboard, but non-cardboard parts are fabricated from recyclable, pure nylon plastic, so it could potentially be more environmentally-friendly than your average vacuum cleaner.

Vax is considering a small run of the cardboard vacuum cleaner.

Cardboard and plywood car

The Flatpack cardboard and plywood car was produced by Aston University students for Rotterdam's Shell Eco-Marathon in 2012 and contains cardboard, plywood, bio-resin and hessian fiber-based tires, and even a hydrogen-powered engine. The car's body is made from cardboard, which is then sandwiched between plywood to improve structural integrity, and the entire structure is collapsible to ease shipping hassles.

Rapid Packing Container

Okay, this one actually is just for packaging... The Rapid Packing Container is the product of student inventors Chris Curro and Henry Wang, who were awarded a $5,000 grand prize for Cooper Union's first Invention Factory event.

Its unique cut-out shape and creasing pattern facilitates easy construction and sealing with just one easy motion, no tape required. Additionally, the box is opened with a quick tug, and can return back to a flat state, ready for re-use, no tape required.

The students are currently exploring the possibility of launching the Rapid Packing Container as a product.

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