BRIEF DESCRIPTION OF DRAWINGS
The invention will be better understood from the description that follows, with reference to the annexed drawings, in which:
FIG. 1 is a view of the prior art;
FIG. 2 is a perspective view of a first embodiment of the invention;
FIG. 3 is a cross-sectional view of the interface device of FIG. 2;
FIGS. 4 to 8 are cross-sectional views of alternative constructions of the second embodiment of the invention;
FIG. 9 is a perspective view of a second embodiment of the invention;
FIG. 10 is a cross-sectional view of the interface device of FIG. 9;
FIG. 11 is a top view of the stiffener of the interface device of FIG. 9.