Nozzle and fastening element for fastening a material layer
The invention relates to a nozzle ( 10 ) for fastening a material layer to a substructure, comprising a plate ( 12 ) and a hollow shank ( 14 ), integrally formed thereon, for taking a fastening screw ( 24; 34 ), wherein a stepped bore ( 16 ) is provided in the hollow shank, wherein the stepped bore ( 16 ) comprises at least two steps ( 28; 38; 50 ) between at least three regions ( 18; 30; 36; 2 ), wherein the hollow shank ( 14 ) is formed so as to taper at least partially in a conical manner on an external surface, wherein the hollow shank ( 14 ) is provided with radially expandable elements, and wherein the expandable elements are formed as axial grooves ( 40 ) externally in that part of the hollow shank ( 14 ) that is formed in a conically tapering manner. The invention proposes that the grooves ( 10 ) are each provided at the groove base at least partially with a thin bottom ( 42 ) that is stretchable or breakable by the expansion. The present invention also relates to a fastening element comprising a nozzle ( 10 ) according to the invention and a fastening screw ( 24; 34 ).
1. A nozzle ( 10 ) for fastening a material layer to a sub-structure, comprising a plate ( 12 ) and a hollow shaft ( 14 ) integrally formed thereon for receiving a fastening screw ( 24 ; 34 ), a stepped hole ( 16 ) located in the hollow shaft, the stepped hole ( 16 ) comprising at least two steps ( 28 ; 38 ; 50 ) between at least three regions ( 18 ; 30 ; 36 ; 52 ), each of the at least two steps forming an axial stop for a screw head of a corresponding size, the hollow shaft ( 14 ) being formed so as to taper conically at least in part on an outer surface, the hollow shaft ( 14 ) being provided with radially expandable elements and the expandable elements being formed by portions of the hollow shaft ( 14 ) that are separated from one another by axial grooves ( 40 ) on an outside in the conically tapering part of the hollow shaft ( 14 ), a thin base ( 42 ) formed at least in part along a bottom of each of the grooves ( 40 ), the thin base ( 42 ) being sized to be stretched or broken by expansion of the expandable elements.
2. The nozzle ( 10 ) according to claim 1 , wherein the at least three regions ( 18 ; 30 ; 36 ; 52 ) have different diameters which each remain constant.
3. The nozzle ( 10 ) according to claim 2 , wherein the different diameters of the at least three regions ( 18 ; 30 ; 36 ; 52 ) which remain constant over the respective regions decrease starting from an end of the hollow shaft ( 14 ) facing the plate ( 12 ).
4. The nozzle ( 10 ) according to claim 1 , wherein the grooves ( 40 ) are each open at the end thereof opposite the plate ( 12 ).
5. The nozzle ( 10 ) according to claim 1 , wherein the hollow shaft ( 14 ) is provided, at an end thereof opposite the plate ( 12 ), at least with two diametrically opposed axial grooves ( 40 ) as expandable elements.
6. A fastening element for fastening a material layer to a sub-structure, wherein the fastening element is in two parts and comprises a nozzle ( 10 ) according to claim 1 , and a fastening screw ( 24 ; 34 ) which is received by said nozzle and is installable in the sub-structure.
7. The fastening element according to claim 6 , wherein the screw has a thread-free shaft portion ( 44 , 46 ) directly below the head ( 26 , 48 ).
8. The fastening element according to claim 7 , wherein the thread-free shaft portion ( 44 , 46 ) of the fastening screw ( 24 ; 34 ) is received in at least one of the at least three regions ( 18 ; 30 ; 36 ; 52 ) without radial play.
9. The fastening element according to claim 6 , wherein the fastening screw ( 24 ; 34 ) which has been inserted into the nozzle ( 10 ) is held without play in a pre-mounted state by one of the at least three regions ( 18 ; 30 ; 36 ; 52 ) or axially abuts one of the at least two steps ( 28 ; 38 ; 50 ).
10. The fastening element according to claim 6 , wherein a material of which the nozzle ( 10 ) is made has a lower strength than the fastening screw ( 24 ; 34 ), and therefore the stepped hole ( 16 ) is expandable by the fastening screw ( 24 ; 34 ).