Super-shortened multiple-fold umbrella

Abstract

A multiple-fold umbrella includes a telescopic central shaft having seven tubes telescopically coupled with one another, with an outermost tube having no (or zero) concave portion formed on the outermost tube, and with an innermost tube having six concave portions circumferentially formed on the innermost tube, each concave portion recessed in the tube centripetally about a longitudinal axis of the shaft and defining a central angle of sixty degrees, and the tubes gradationally increasing the number of the concave portions from the outermost tube towards the innermost tube to define an air chamber between a concave portion of an inner tube and a circular periphery of an outer tube neighboring to the inner tube for a smooth slidable coupling of every two neighboring tubes.

1 . A multiple-fold umbrella comprising: 
 a central shaft including a plurality of tubes telescopically coupled with one another about a longitudinal axis defined at a longitudinal center of the shaft;    a runner sleeve disposed, jacketed or formed on said central shaft and having a protrusion formed on said runner sleeve; and    a multiple-fold rib assembly pivotally secured to an upper notch formed on a top of said shaft and pivotally secured to a runner slidably held on said runner sleeve; said runner operatively engaged with said protrusion of said sleeve to be locked on said sleeve when opening the umbrella; said plurality of tubes gradually or gradationally increasing the number of concave portions formed on the tubes from an outermost tube towards an innermost tube of the shaft; each said concave portion recessed centripetally from a circular periphery of the tube towards said longitudinal axis of said shaft and each said concave portion defining a central angle, which is less than ninety degrees, of a 360-degree circle of each said tube; every two neighboring tubes having an increment of one concave portion between an inner tube and an outer tube neighboring with each other and defining an air chamber between a concave portion of the inner tube with a circular periphery of the outer tube; whereby upon sliding engagement of the concave portions of the outer tube with the concave portions of the inner tube, said outer and inner tubes are reliably engaged or coupled without being twisted or rotated; and said tubes are smoothly coupled without being frictionally braked as effected by each said air chamber defined between said outer and inner tubes.    
   
   
       2 . A multiple-fold umbrella according to  claim 1 , wherein each said concave portion defines a central angle of sixty degrees.  
   
   
       3 . A multiple-fold umbrella according to  claim 1 , wherein said central shaft includes: a first or outermost tube formed as a circle shape having zero concave portion formed thereon, a second tube inside said first tube having a concave portion recessed in said second tube, a third tube inside said second tube having two concave portions recessed in said third tube, a fourth tube inside said third tube having three concave portions recessed in said fourth tube, a fifth tube having four concave portions recessed therein, a sixth tube having five concave portions recessed therein, and a seventh or innermost tube having six concave portions recessed in said seventh ture, whereby upon telescopic coupling of all said tubes, a hepta-fold central shaft is formed.  
   
   
       4 . A multiple-fold umbrella according to  claim 1 , wherein said runner includes a socket formed in said runner to be engaged with said protrusion on said sleeve when opening the umbrella.  
   
   
       5 . A multiple-fold umbrella according to  claim 4 , wherein said runner includes an actuator formed in said runner, said actuator operatively depressing said protrusion inwardly to disengage said runner from said protrusion for closing the umbrella.  
   
   
       6 . A multiple-fold umbrella according to  claim 1 , wherein said rib assembly includes at least a top rib pivotally secured to an upper notch formed on a top of said shaft, a stretcher rib pivotally secured to said to rib and said runner, an intermediate rib respectively pivotally secured to said top rib and said stretcher rib, and a tail rib pivotally secured to said intermediate rib; the improvement which comprises said tail rib having a cross section of U shape.  
   
   
       7 . A multiple-fold umbrella according to  claim 6 , wherein said rib assembly is a penta-fold rib assembly, having said tail rib pivotally secured to said intermediate rib respectively through an auxiliary intermediate rib connected to said intermediate rib and through an outer connecting rib connected to said auxiliary intermediate rib.  
   
   
       8 . A central shaft adapted for multiple-fold umbrella comprising a plurality of tubes telescopically coupled with one another about a longitudinal axis defined at a longitudinal center of the shaft; said plurality of tubes gradually or gradationally increasing the number of concave portions formed on the tubes from an outermost tube towards an innermost tube of the shaft; each said concave portion recessed centripetally from a circular periphery of the tube towards said longitudinal axis of said shaft and each said concave portion defining a central angle, which is less than ninety degrees, of a 360-degree circle of each said tube; every two neighboring tubes having an increment of one concave portion between an inner tube and an outer tube neighboring with each other and defining an air chamber between a concave portion of the inner tube with a circular periphery of the outer tube; whereby upon sliding engagement of the concave portions of the outer tube with the concave portions of the inner tube, said outer and inner tubes are reliably engaged or coupled without being twisted or rotated; and said tubes are smoothly coupled without being frictionally braked as effected by each said air chamber defined between said outer and inner tubes.