Abstract: An installation for the actuation of several controllable elements with modulated pressures, whereby the elements are constructed in particular as air chambers accommodated in the upholstery of a motor vehicle seat; the installation consists of only one pressure modulator and of a distribution device series-connected therewith; the pressure modulator is adapted to be selectively connected with one or several of the controllable elements by way of this distribution device.

Abstract: A seat cushion adapted to be concealed in a back rest area of a motor vehicle seat includes a number of superimposed chambers, with the chambers being individually inflatable for individual support of a spinal column of the user of the seat. The individual chambers are delimited at intervals by a connecting ribs, with each connecting rib following along staggered paths and, preferably, along staggered undulating paths so that adjoining chamber walls form a tooth-like meshing. Thus, a transition area formed by the tooth-like meshing of the chambers is percieved as comfortable when the chambers are inflated to different hardnesses.