A Swedish inventor Bertil Sjösvärd has developed Gripforce, a line of winter boots with retractable spikes in the soles that allows them to quickly swap between cleats and regular boots with the flip of a switch.
In normal mode, the spikes on the bottom of a Gripforce boot are tucked away inside cavities and the rigid sole keeps them from protruding out into the ground. But when the spikes are turned on, using a little switch located on the inner side of each boot, the sole loosens up, and the weight of the wearer pushes the spikes down into the ground surface.
The idea is that they will penetrate into soft ground like ice and snow, but stay withdrawn inside the sole on more solid surfaces, like concrete or tiles. That said, the creator is quick to point out that wearers should make sure the shoes are in off-mode before strolling across a wooden floor.
Bertil Sjösvärd says the technology in the shoes is covered by two patents – one for the system that uses the wearer's body weight to force the spikes out, and the other for the changing rigidity of the soles.
