A fastener is disclosed for affixing void-forming members to underlying concrete slabs for use in composite slab construction. Each fastener comprises a stem having a cross limb with a barbed end for insertion into a foam member, a stabilizer bar transversely projecting from one side of the stem intermediate...http://www.google.de/patents/US4718210?utm_source=gb-gplus-sharePatent US4718210 - Fastener for void-forming member
