Automatic collapsible umbrella structure

Abstract

An automatic collapsible umbrella according to the invention includes a solid shaft secondary rib, and middle junctions provided at pivotal connection portions of the secondary rib with an inner rib and the secondary rib with a connection rib. Without requiring provision of openings at the secondary rib, corresponding connection openings and channels are instead disposed at the middle junctions, thereby providing the secondary rib with higher flexibility strength for reducing chances of bending, and effectively minimizing a volume of the secondary rib for further substantially reducing an entire volume of the collapsed umbrella for easy portability.

What is claimed is:  
     
         1 . An automatic collapsible umbrella comprising a middle rib formed by pivotally connecting a front strut and a rear strut, an inner rib having one end thereof pivotally connected to an upper nest and the other end thereof pivotally connected to a middle section of a secondary rib, the secondary rib has one end thereof pivotally connected to a middle nest and the other end thereof pivotally connected to the front strut, and a connection rib supporting between the secondary rib and a lower nest; and being characterized by: 
 the secondary rib being a solid shaft; and middle junctions provided at pivotal connection portions of the secondary rib with the inner rib, and the secondary rib with the connection rib; and a bent portion pre-formed at the pivotal connection portions of the secondary rib, respectively.    
     
     
         2 . The automatic collapsible umbrella in accordance with  claim 1 , wherein the middle junctions are clamped and fastened around the secondary rib; that is, the middle junctions are U-shaped for wrapping around an outer periphery of the secondary rib.  
     
     
         3 . The automatic collapsible umbrella in accordance with  claim 1 , wherein the bent portion pivotally connecting the inner rib is bent toward the inner rib pivotally connected, and a pivotal axis is penetrated into an axis opening of the middle junction and is exactly fastened at an inner side of the bent portion.  
     
     
         4 . The automatic collapsible umbrella in accordance with  claim 1 , wherein the bent portion pivotally connecting the secondary rib and the inner rib is bent toward a reverse direction of the inner rib, and the pivotal axis is directly fastened within the axis opening of the middle junction.  
     
     
         5 . The automatic collapsible umbrella in accordance with  claim 1 , wherein the middle junction is directly clamped and wrapped around a middle section of the vertical secondary rib, and the middle junction is provided with a connection portion for coordinating and connecting to the inner rib and the connection rib.  
     
     
         6 . The automatic collapsible umbrella in accordance with  claim 1 , wherein the bent portion at the secondary rib for coordinating with the inner rib and the connection is an integral with the secondary rib; that is, the secondary rib is provided with only one bent portion, and a middle junction for connecting to the inner rib and the connection rib.