Abstract: The wheelchair (10) has a closed, three-dimensional frame (12). The latter is constituted by a front horizontal transverse support (12.1), two lateral supports (12.2, 12.3), which are arranged symmetrically in respect to the longitudinal center axis, and a rear, essentially horizontal transverse support (14). The lateral supports have the shape of a letter L with respectively an upright leg (12.2), which laterally adjoins the front transverse support (12.1), and with a rearward oriented longitudinal leg (12.3). A front wheel support (25), on which a front wheel (24) is mounted, is fastened on each upright leg (12.2) of the longitudinal supports.

Abstract: A collapsible wheelchair (10) with two lateral supports (12, 13) on which respectively a drive wheel (18, 19) and respectively a running wheel (20, 21) are fastened and which are rigidly connected by a main transverse support (34) and an auxiliary transverse support (32). The former is constituted by two legs (38, 39) connected a hinge joint, which can be arrested on each other by an arresting device. The latter has an arresting protrusion (56) hinged on one leg (38). The arresting protrusion runs up on the stop face (62) respectively located opposite it, which is a section of a stop area (64) formed on the other leg (39). At least one of the legs (38, 39) can be advanced in the direction toward the longitudinal center surface of the collapsible wheelchair (10) by an advancement device.