Abstract: Screw made of plastic for screwing into a material of low strength, e.g. rigid foam plastic, having a deep thread compared with the screw shank, the screw shank running out conically into a screw point. The screw has the following features: 1. the depth of thread H and the minor diameter Dk of the thread form a quotient Q1=H/Dk in the order of magnitude of 1 to 3.5, preferably 2; 2. the minor diameter Dk and the thread pitch P form a quotient Q2=Dk/P in the order of magnitude of 0.3 to 0.6, preferably 0.5; 3. the thread is designed as a V-thread having a vertex angle of the thread teeth of less than 30°.

Abstract: The invention relates to a device for securing a structural element provided with a hole to a panel-like component, said panel-like component being fitted with a stay-bolt onto which can be pressed on the side opposite the component a hollow cylindrical part with a flange, said hollow cylindrical part being able to be received by the hole and having a latching portion, the flange having a diameter greater than the diameter of the hole. A metal part, forming the latching portion and having a plurality of latching lugs, is inserted into the hollow cylindrical part, wherein the hollow cylindrical part has a spring portion which yields to axial pressure and the structural element is provided on its side facing the component with an inwardly directed collar on which rests the hollow cylindrical part with its end opposite the flange when the hollow cylindrical part is in the secured position with the spring portion pressed in.

Abstract: Screw made of plastic for screwing into a material of low strength, e.g. rigid foam plastic, having a deep thread compared with the screw shank, the screw shank running out conically into a screw point.