A canopy has a framework including a plurality of vertical poles and a roof frame. A height adjustment structure for adjusting the height of the roof frame includes a sliding sleeve disposed around each vertical pole, to which the roof frame is connected. The sleeve can slide along the pole so that a...http://www.google.co.uk/patents/US20060169311?utm_source=gb-gplus-sharePatent US20060169311 - Height adjustment structure for a canopy
