Foldable structure of large-sized umbrella

Abstract

A foldable umbrella includes a center rod having an upper end to which a primary crown is attached. A primary runner is movable along the central rod toward/away from the primary crown for opening/closing the umbrella. Pairs of secondary crown and runner are equally spaced around the primary crown and runner. A first intermediate bar has opposite ends pivoted to the primary crown and each secondary runner. A second intermediate bar has opposite ends pivoted to the primary runner and each secondary crown. The first and second intermediate bars intersect and are pivoted to each other whereby a parallelogram linkage is formed, which drives the secondary runners simultaneously with the movement of the primary runner in opening/closing the umbrella. A first rib bar extends radially from each secondary crown and a stretcher bar is arranged between and having ends pivoted to each first rib bar and the associated secondary runner. A canopy is attached to the crowns and supported by the rib bars whereby when the umbrella is open, the canopy is expanded by the secondary crowns and the rib bars. If desired, second rib bars may be pivoted to each secondary crown and radially extend therefrom for further supporting the canopy. Corresponding stretcher bars are provided between the second rib bars and the associated runners.

What is claimed is:  
     
         1 . An umbrella comprising: 
 a central rod having an upper end;    a primary crown mounted to the upper end of the central rod and a primary runner movable along the central rod toward/away from the primary crown for opening/closing the umbrella;    at least one pair of secondary runner and secondary crown respectively corresponding in position to the primary runner and crown and radially spaced therefrom;    a first intermediate bar having opposite ends respectively pivoted to the primary crown and the secondary runner and a second intermediate bar having opposite ends respectively pivoted to the secondary crown and the primary runner;    at least one first rib bar pivoted to each secondary crown and radially extending therefrom;    a stretcher bar having ends respectively pivoted to each rib bar and the associated secondary runner; and    a canopy attached to the crowns and supported by the rib bar.    
     
     
         2 . The umbrella as claimed in  claim 1  comprising two pairs of secondary crowns and runners arranged on opposite sides of the primary crown and runner, second rib bars pivoted to the primary and secondary crowns and radially extending therefrom for supporting a rectangular canopy.  
     
     
         3 . The umbrella as claimed in  claim 1  comprising four pairs of secondary crowns and runners equally spaced around the primary crown and runner for supporting a square canopy.  
     
     
         4 . The umbrella as claimed in  claim 1 , wherein the first and second intermediate bars intersect and are pivoted to each other.  
     
     
         5 . The umbrella as claimed in  claim 4 , wherein the bars form at least one parallelogram linkage.