Patent ID: 7591274

Claim:
An umbrella comprising: a central shaft having an upper hub formed on a top portion of said central shaft; said upper hub including: a plug member secured to the top portion of the central shaft, the plug member having a male-threaded portion formed on an upper portion of the plug member, a plurality of projections circumferentially formed bellow the male-threaded portion, and a lower portion extending downward from the projections and having an annular protrusion circumferentially formed thereon; and a cap having a female-threaded portion formed in the cap to be engaged with the male-threaded portion of the plug member and having a flange circumferentially formed on a perimeter of the cap for covering the plug member; an one-piece frame including a plurality of rib assemblies respectively integrally formed with an upper ferrule secured to said upper hub and integrally formed with a lower ferrule of a lower runner slidably held on said central shaft; said upper ferrule including a central hole for passing the male-threaded portion therethrough and a plurality of recesses formed in an annular bottom portion of the upper ferrule to be engaged with the plurality of projections circumferentially formed on the plug member to secure the upper ferrule on the plug member of the upper hub, whereby upon protruding of the male-threaded portion of the plug member through the central hole of the upper ferrule and upon engagement of the cap on the male-threaded portion, the upper ferrule will be firmly retained on the upper hub and on the top portion of the central shaft, and the flange of the cap covers the upper ferrule, said lower runner including a slide member defining a cylindrical hole in the slide member; said lower runner having a plurality of stretcher ribs formed with said lower ferrule and formed on an upper portion of the slide member, the stretcher ribs integrally connected with the rib assemblies respectively; the lower runner having a lower ferrule hole formed through the lower ferrule and communicated with the cylindrical hole to be slidably movable on the central shaft; and a shoulder portion formed in between the lower ferrule hole and the cylindrical hole to be releasably engaged with the annular protrusion of the plug member to form a catch means for locking the lower runner on an upper portion of the central shaft when opening the umbrella; and said lower runner further including a sleeve embedded into the cylindrical hole of the slide member of the lower runner and is slidably engaged with the central shaft; and an umbrella cloth secured on said one-piece frame.