Industrial Automation in German

No.11785798 ViewReplyOriginalReport
I'm an engineer working on a code that's been written in German. Would some of you folks be so kind to help me find out what "QD" stands for? The context is industrial automation:

"
QD-Zubringer vor
QD-Zubringer zurück
QD abwerfen (Transportkette vor)
QD im Bereich Zubringer
"