New York designer Karim Rashid has unveiled a smartphone charging device that neatly stores a metre-long cable in a loop around its outside (+ slideshow).

Ovaloid in shape, the Bump charger can be plugged into a wall to provide constant power or used as a battery pack while on the go.

When not in use, its one-metre USB cable can be wound away and tucked into the removable hollow band that fits around its middle.

"Bump eliminates the knotty tangle of power cords that we currently endure," said Rashid, who is known for his brightly coloured, curvaceous designs.

His previous products include a baby's bottle that heats milk to body temperature without using electricity and a range of watches for Alessi.

Bump features a row of lights up its front that indicate the amount of remaining power, and a circular button below that turns the device on or off. The prongs used for wall-charging fold away into the back of the charger, which comes in a range of colours.

Others designer smartphone chargers include Yves Behar's octagonal portable gadget that can accommodate multiple devices at once and Olafur Eliasson's solar-powered product with a built-in lamp.

However, Ikea has aimed to do away with chargers entirely by integrating wireless ports into a range of furniture and homeware.

Bump is the first in a line of accessories from a new brand called Push and Shove. Rashid worked with entrepreneurs Richard Smiedt and Phil King to co-found the company, which aims to "create products that give equal weight to form and function".

Born in Egypt, Rashid was raised in Canada and studied industrial design at Ottawa's Carleton University. In 1992, he opened his own studio in New York, which designs products, architecture and interiors.

Last year, Rashid asked his Facebook followers to select their preferred option from four facades for a building in New York, and completed the interior of a sex shop in Munich.