tubular members a relatively inexpensive but highly effective mechanism which permits easy folding and opening of the wheelchair is provided in addition it can be observed that only one t fitting is required as for example the mounting sleeves 86 and the telescopic connecting posts 88 on each of the opposite sides of the wheelchair these t fittings are usually one of the more expensive components in the frame of a foldable wheelchair in the prior art wheelchair constructions it was necessary to employ a pair of t fittings on each of the opposite sides of the wheelchair or a total of four t fittings thereby materially increasing the cost of construction of the prior art wheelchairs inasmuch as the sleeves 74 and 76 do not have to rotate with respect to the upper frame bar 28 and also since the sleeves 60 and 62 do not have to rotate with respect to the upper frame bar 30 they are affixed thereto by means of set screws 90 as illustrated in fig6 of the drawings in this way the sleeves 74 and 76 restrain axial movement of the upper frame bars 28 and 30 and thereby also restrain the mounting sleeve 86 from axial movement on the frame bar.