"Canal-shaped interlocking recesses lead into the collection bags. Stop elements plunge into these recesses when the concerned (respective/particular) safety side panel is swung vertically upright and sinks due to its own weight".



Aufnahmetaschen can be translated to 'collection bags' if it's a medical context (see this link):
http://dir.indiamart.com/indianexporters/ms_medic.html

Anschlag, among other things, means retainer, fixing, fastener. I translated Ansclagelement to stop elements since this seems to be the term used for beds (your context right?) - see second link below

see first link below for 'interlocking recesses' in mattresses