Lopers are employed in bachelor’s chests etc. to support their fold-out leaves and in bureaux to support their falls. I covered the installation of lopers in A George II ash bureau – Part VII.
As I mentioned during the construction of the ash bureau, a vertical divider (and, on occasions, a guide, too) is required between loper and drawer to ensure both operate unimpeded (figs. 1 & 2).
Fig. 1. Loper and vertical divider (with guide behind).
I recently came across this unusual – but rather nifty – approach to the issue (figs. 3 & 4).
The brasses are rather splendid too.