Connecting device for pneumatic apparatus

In a connecting device for pneumatic bases each having two opposed parallel coupling faces provided with orifices to be associated, and a support face perpendicular to the former and adapted to receive a removable pneumatic switching component, two opposed coupling faces of two adjacent bases being applied one against the other by means of screws the axes of which are inclined with respect to these faces, and which each have a threaded end cooperating with a nut situated in a housing of one of the bases, a head opposite to this end bearing on a shoulder of an adjacent base, and an intermediate portion placed in two channel portions one in extension of the other, these portions being situated respectively between the common plane of two coupling faces at which they open, and respectively the nut and the shoulder, the improvement which comprises the nut is constituted by an element which pivots about an axis parallel to said coupling faces and which is placed in a base of a first portion of channel opening at the support face, the length of the screw being such that its head is disposed below said support face when its axis is perpendicular to the latter, and said head is pressed on a shoulder disposed in a second portion of channel opening at the support face of an adjacent base and in the vicinity of said support face, when the axis of the screw is inclined, two screws being respectively placed in two parallel planes between which open the orifices to be connected.