<p>The supporting floor has a carrying pin (1), and at its lower end a bolt head (2), and underneath the pin head an insulating unit (14). The bolt head is on a load distribution element (7) made from plastic and arranged between the bolt head (2) and the insulating unit. The strength of the insulating unit bolt head is distributed on the load distribution element by contacting the surface (16) of the insulating unit. A ball joint-like connection is between the bolt head and the load distribution element.</p>
