A motor vehicle air conditioning installation includes a pair of parallel tubes with annular beads at their free ends, for assembly to a component of the fluid circuit of the installation, and a clamping plate or strut connecting the two tubes together. The strut is an elongated plate having two through apertures. One of these is a notch open at one end of the plate. Each aperture has a substantially semicircular region matching the circumference of the associated tubular element fitting within it. The second aperture is surrounded by the material of the plate over its whole periphery, and includes a widened region through which the associated bead of the corresponding tubular element can pass, this widened region being joined directly to the substantially semicircular region. The strut cannot be separated from the tubes without resilient deformation of the latter, which avoids the danger of its becoming lost during disassembly.