| 摘要 |
The invention relates to a spiral staircase, in particular a newel-type spiral staircase with stairs (and landing) (11) which are screwed onto a storey-high central tube (1) by means of two screw-bolts (4 + 5) located next to each other. Said screw connection observes, above all, the fulfilment of requirements with respect to statics. The screw-bolts (4 + 5) located next to each other comply with the principle "one screw is no screw at all", and the curved counter-plate (6) with threaded bores for receiving the screw-bolts (4 + 5) is adapted, flatly and over a large surface area, to the tube inner wall. A third threaded bore (9) serves for the temporary fixing of the counter-plate (6), which is introduced into the pipe interior by means of a tool which is fastened in the threaded bore (7). On the building site, the screw-bolts (4 + 5) are screwed into the counter-plate (6) and the threaded pin (10) is removed. The stairs (11) - and the landing - whose top part (12) has fitting bores (13 + 14) in each case, can then be plugged one after the other over the screw-bolts (4 + 5) and be screw-connected to the central tube (1) by means of nuts (17 + 18) with correspondingly shaped washers (15 + 16). The bores, only on one side, for each rise in the central tube (1) are configured as slots (2 + 3), with the result that an exact arrangement of the stairs is possible. <IMAGE>
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