A fitting for transverse joining of two L-shaped sections is provided,
each L-shaped section with a web part and a foot part. The sections are
disposed with the web part back-to-back, being peculiar in that the
fitting substantially includes a first flange and a second flange which
are J-shaped and which in mutual contact are slidingly connected with a
connection for constituting a largely C-shaped fitting with a gap of
variable length for accommodating the two foot parts of the L-shaped
sections. The fitting includes means for mutual fixation of the two
flanges for retaining the length of the C-shaped fitting after receiving
both foot parts in the C-shaped fitting.