Abstract: An umbrella comprises: a central shaft having an upper hub formed on a top portion of the central shaft; an one-piece frame having a plurality of rib assemblies integrally formed with an upper ferrule and a lower ferrule, with the upper ferrule secured to the upper hub and with the lower ferrule formed with a lower runner slidably held on the central shaft; and an umbrella cloth or cover secured on the frame; thereby forming an umbrella which can be easily constructed for use; and can also be easily detached, when damaged, for reclaiming the parts or elements in construction of the umbrella for environmental protection purpose.