U bicycle rack / Bicycle rack

In cramped space for example wayside, narrow alley, it is difficult to park the bicycle. Because, there is little space to install the bicycle rack. Becides if it is installed in narrow space, when people unuse the rack pedestrians and passing cars are very inconvenient.
So for this narrow space, "U bicycle rack" is flexible for different situations. When people unuse it, up the U rack. Then space never decrease. And people use it, down the U rack and use it. Like this "U bicycle rack" is space saving installation.