PURPOSE: To surely prevent a clamping plate from dropping and losing, irrespective of the relative positions of two tubular parts, in separating the tubular parts of a motor vehicle air conditioner from components of a hydraulic circuit.

CONSTITUTION: The apparatus comprises a pair of parallel tubes with annular beads at their free ends, a clamping plate connecting the two tubes together, the clamping plate is an elongated plate having two holes 2, 3, one hole 2 is opened at one end of the plate 1, and each hole 2, 3 has a semicircular region 4, 6 fitted within the associated tubular part. The second hole 3 is surrounded by the material of the plate 1 over its whole periphery, and includes a widened hole region 7 through which the bead of the corresponding tubular part can pass, this widened hole region 7 being joined directly to the semicircular region 6 of the second hole 3.