Washer (hardware)

Washers, washers or shims are used to distribute the force of the screw head of a screw or nut on a larger area. Washers are hardened in rare cases, so that the deformations in pre-stressed bolted connections remain calculable, and no flow occurs. Washers, there are, for example, metal, felt, plastic.

Function

For soft materials (eg, wood ) have the task of washers to distribute the biasing force on a larger area. This lowers the surface pressure and therefore prevents the sinking or burial of the screw head into the soft material.

Dimensions

• Washers of metal compounds have - apart from the small discs - having an outer diameter of about 1.8 to 2 times the bore diameter.
• With washers for wood constructions ( DIN 440, ISO 7093 ) are the outer and bore diameter in a ratio of about 3:1.

• Preferably, for hexagon bolts and nuts Slices, execution medium according to ISO 7089 without chamfer (formerly DIN 125 -A ), ISO 7090 with chamfer ( DIN 125 - B), ( engineering standard) )
• Slices, execution roughly according to ISO 7091 ( formerly DIN 126)

Special shapes

• There are still works standards and designs for washers.
• Diameter washer and fender washer ( formerly DIN 9022 ): Extra wide plate for assembly of ( thin ) pieces.
• Fitschenring: the diameter of a mandrel of hinges ( " door hinges " ) and the outer diameter adapted to the washer.

Spring washers

Spring washers are not among the washers because its function is more the screws securing serves. See also: tooth washer, spring washer