This is a long shot, Steffen. Inspiration came from Langenscheidt Technik, where Nuss (Einsatz zum Aufstecken, z.B. auf Knarre) is translated as socket.

Chains with sockets have good tensile strength, which makes it possible to achieve sinuous paths of great length. They also allow driving by the side, which is particularly economical. Another advantage of these chains with sockets lies in the fact that the path of the pallets may be entirely in one horizontal plane and therefore used over its entire length, without a return length below the useful length. The guidance of the chain is achieved by links which slide in a profiled section or an assembled profiled section.

The conveyor chain 31 is a socket chain of a known type, the links 32 of which are connected by rivets 33 on which the sockets 34 are engaged.

http://www.freepatentsonline.com/20060151300.html

perhaps, if Nusskette = Kettennuss

Kettennuß f MASCHINEN chain sprocket, sprocket wheel (Langenscheidt Technik)


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Note added at 36 mins (2007-11-06 17:50:25 GMT)
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BTW, acc. to Enrst:

Kettennuß = Kettenwirbel m, / sprocket [wheel], chain sprocket