please refer to fig4 and 5 that are fragmentary perspective and cross - sectional views , respectively , of a tubular strip 20 according to a preferred embodiment of the present invention for use on a leisure chair . the tubular strip 20 is in the form of a hollow tube made of a specific pliable pvc material , and has a wall thickness ti that is significantly reduced as compared to the wall thickness t of the conventional tubular strip 14 shown in fig2 and 3 . in the illustrated embodiment , the wall thickness t 1 of the tubular strip 20 for leisure chair is about one third ( ⅓ ) to one half ( ½ ) of the wall thickness t of the conventional tubular strip 14 . the tubular strip 20 of the present invention is characterized by a plurality of axially extended reinforcing ribs 22 circumferentially spaced on an outer surface of the tubular strip 20 . though not necessary , the reinforcing ribs 22 in the illustrated embodiment are angularly arranged on the outer surface of the tubular strip 20 at equidistance . for example , the reinforcing ribs 22 may be spaced from one another by 45 degrees on the tubular strip 20 . however , it is understood the present invention is not limited to the above design . that is , for the sake of saving material , the reinforcing ribs 22 on the outer surface of the tubular strip 20 may be in the number and at angular positions determined according to actual need in forming differently designed leisure chairs . please refer to fig6 . when a plurality of tubular strips 20 of the present invention are parallelly positioned and tightly stretched over the leisure chair to form the back , the seat , and the footrest , the tubular strips 20 subject to the stretch have each a hollow elliptic cross section that provides relatively larger force - bearing surface area . the parallelly positioned and tightly stretched tubular strips 20 are then welded at predetermined positions to firmly fix on frames of the leisure chair . when the tubular strips 20 that are welded together and firmly fixed to the frames of the leisure chair are subjected to a force , it is the outer surfaces of the tubular strips 20 and the spaced reinforcing ribs 22 provided thereon that together provides the tubular strips 20 with sufficient structural strength to bear the force applied thereto . the tubular strip for leisure chair according to the present invention can be advantageously mass - produced using pvc material by way of injection molding and in procedures exactly the same as the existing ones with slightly modified molds . since the tubular strip 20 of the present invention has largely reduced wall thickness and sufficient structural strength , it enables the leisure chair that uses the tubular strips 20 to cover most areas of the back , the seat , and the footrest of the leisure chair to be manufactured with largely reduced quantity of pvc material and accordingly , at effectively lowered manufacturing cost without being affected by the constantly rising price in the international pvc cash market . moreover , with the reinforcing ribs 22 , the outer surface of the tubular strip 20 provides better air ventilation for forming a more comfortable leisure chair . the present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is to be limited only by the appended claims .
a tubular strip for leisure chair is made of a specific pliable polyvinyl chloride material by way of injection molding , so that the tubular strip has a reduced wall thickness with a plurality of spaced reinforcing ribs integrally molded on an outer surface of the tubular strip to provide a common force - bearing structure .