Umbrella structure

摘要

An umbrella structure includes a shaft, a top notch fixed at the top end of the shaft, a runner mounted around and slidable along the shaft, plural ribs, plural stretchers, a canopy, and plural torsion springs. Each rib has an upper end pivotally connected to the top notch. Each stretcher has an upper end pivotally connected to an intermediate portion of one of the ribs and a lower end pivotally connected to the runner. The canopy can be opened or closed by sliding the runner upward or downward along the shaft. One torsion spring is provided where each rib is pivotally connected to the corresponding stretcher. When the runner is slid downward to close the canopy, each torsion spring is compressed and stores energy. When the runner is slid upward to open the canopy, each torsion spring releases the stored energy to reduce the effort required for opening the canopy.

主权项

1. An umbrella structure, comprising:
a shaft provided with an elastic protruding catch; a top notch fixed at a top end of the shaft; a runner mounted around and slidable up and down along the shaft, the runner being engageable with the protruding catch so as to be fixed in position on the shaft; a plurality of ribs, each said rib having an upper end pivotally connected to the top notch; a plurality of stretchers, each said stretcher having an upper end pivotally connected to an intermediate portion of a said rib by a pivot pin, each said stretcher having a lower end pivotally connected to the runner; a canopy covering and connected to each said rib; and a plurality of torsion springs, each said torsion spring being mounted around a said pivot pin, by which a said rib is pivotally connected to a corresponding one of the stretchers, each said torsion spring having an end fixed to a said rib and an opposite end fixed to the corresponding one of the stretchers; wherein in order to close the umbrella structure, the runner is slid downward from an upper position on the shaft such that not only does the runner drive each said stretcher and each said rib to close the canopy until the runner is engaged with and fixed in position by the protruding catch, but also each said torsion spring is compressed by a said rib and the corresponding one of the stretchers and stores energy therein; and in order to open the umbrella structure, the protruding catch is pressed, and the runner is simultaneously slid upward such that each said torsion spring releases the energy stored therein and generates an elastic restoring force driving a said rib to open the canopy.