Screw with anti-loosening means

An anti-loosening screw apparatus, comprising:

• a screw (1) including a head (12) with a top surface and a circumference surface that protrudes radially from the head (12), wherein at least one of the head (12) and the circumference surface includes a surface structure comprising first flanks (123) that slope in a tightening direction of the screw (1), which transition into one another by second flanks (124) that slope at a steeper angle than the first flanks (123) and in a direction opposite from the tightening direction;
• and
• a securing element (2) including a ring section (21) positionable around a shaft (11) of the screw (1) under a head (12) of the screw and with the screw (1) screwed to a base, to prevent the screw (1) from turning back in a direction opposite the tightening direction;
• at least one projection (231) extending from the ring section (21) of the securing element (2) on a side opposite the head (12) of the screw (1) and oriented toward an associated surface of the base, wherein the at least projection is pressed into a surface as the screw (1) is tightened;
• and
• finger-like appendages (22) extending from an outer circumference region of the ring section (21) and which when the securing element (2) is in an installed position extend along a circumference of the head (12) and under spring-elastic forces of the securing element (2) contact with the surface structure of the head (12) and exerts an inhibiting action against the second flanks (124) in the direction opposite from the tightening direction, wherein the appendages (22) have end sections (223) bent inward and disposed over the top surface of the head (12), an edge region of the top surface, or a circumferential groove in the top surface and containing the surface structure oriented away from the shaft (11).