Spring washer

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Spring washer
Spring washer under a nut that has not yet been tightened

A spring washer is a machine element used as a screw lock . It is inserted between the screw head or the nut and one of the parts to be connected in order to avoid unintentional loosening. As a ring that has been cut open and deformed into the shape of a helical spring, it forms a spring that is too "hard" for the intended purpose ( spring characteristic curve is too steep ). The relatively small force component in the frictional connection also quickly becomes even smaller when loosening (loosening and / or setting the parts to be connected). After this was recognized, the decades-old DIN 127 A and B standards were withdrawn.

A spring washer, in which the cut edges are not deburred (was recorded in DIN 127 A), also creates a form fit within the screw connection. The inclined incision creates axially protruding ridge tips barbs at the interface . These dig into the contact surfaces - especially when loosening them - so that further loosening is hindered. The direction of the incline is adapted to the preferred right-hand thread.

Such spring washers can still be used usefully. In the case of (multi-tooth) toothed lock washers and serrated lock washers that are now on the market , this effect is often exploited.

literature

  • Heinz M. Hiersig: Lexicon of mechanical engineering. VDI Verlag, Düsseldorf 1995, ISBN 3-18-401372-3 .
  • Otto Richter, Richard von Voss: Components of precision mechanics. VDI-Verlag, 1938.
  • Ottomar Fratschner: Machine elements . W. Girardet publishing house, 1961.

See also

Portal: Mechanical engineering  - Overview of Wikipedia content on the subject of mechanical engineering

Individual evidence

  1. ↑ A spring washer is already at 5% of the nominal preload force of screws of strength class 8.8 on the block and only acts like a washer. See Hubert Hinzen, Maschinenelemente 1 , Oldenbourg Wissenschaftsverlag, 2007, ISBN 3-486-58081-7 , p. 370

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