Prefabricated staircase step connecting socket - has durable elastic coating on internal thread engaged by bolt

摘要

A bolt for screwing into a threaded socket, with an elastic securing device in the thread pitch, is used for connecting tread slabs of ready-for-assembly staircase units which have no risers. The internal thread (30) of the socket (15) has a permanently elastic coating (29), at least in the area engaged by the bolt thread (31). This may fill all the intervening hollow spaces and can be made of thermoplastic material. The socket may have cast or concreted anchors (17), or be glued in. This prevents noise arising from, thread play, but can also be easily released if necessary.