Patent attributes
An automatic opening umbrella having a canopy, and a support shaft and an opening mechanism offset or eccentric from the center of the canopy, is described. The opening mechanism includes a framework including varying length rib, link and brace sets on each side of a longitudinal axis of symmetry of the umbrella, the sets being mirror images, with equal numbers of ribs, links and braces. The longest links at distal ends are pivotally connected to a respective longest rib and the longest braces are pivotally connected at distal ends to respective longest links at a mutual connection with the longest link connections to the longest ribs. The shorter links are pivotally connected at distal ends to shorter ribs along the rib lengths. The shorter braces are pivotally connected at distal ends to respective links along the lengths of the links. The ribs at proximal ends are all connected to an upper ring fixed to the shaft and the proximal ends of the links and braces are respectively pivotally connected to intermediate and lower rings that are slidably mounted on the shaft and which are spring biased to separate from each other along the shaft for automatic opening of the umbrella. A geometric relation between lengths of links and braces is described.
