Abstract: A seat back suitable for a vehicle incorporates a mechanically adjustable lumbar support. A flexible panel (9) is mounted by hooks (8) on a rigid frame (6). In the lumbar region pockets (13) formed at the margins of the panel house the central regions (15) of strip spring steel springs (16). The upper and lower ends of each spring curve rearwardly from the panel. The upper ends are interconnected by a cross member (18) and the lower ends are interconnected by a cross member (19). A Bowden cable (22) controlled by a manual or powered actuator is provided for moving the cross members (18, 19) towards each other and thereby causing the central regions (15) of the strip springs to bow outwardly and increase the amount of lumbar support provided by the panel region therebetween.

Abstract: A system for inflating e.g. a pair of lumbar support bags of a vehicle seat comprises two pumps each connected to a respective bag and controlled by a common electronic control system. The control system causes each bag to be inflated over a period of between 1 and 10 minutes, the inflation of one bag taking place while the other bag is deflated and vice versa to produce alternating pressure zones in the lumbar region. Inflation of each bag is produced by a multiplicity of individual spaced apart energizations of the associated pump. The duration and spacing of the energizations is variable to produce the desired complete inflation of a bag within the required period. In the preferred embodiment the duration of each energization is preset during manufacture of the system but the spacing of the energizations is under the control of the user of the seat to vary the duration of the inflate/deflate cycle.