A method for manufacturing washer includes steps of providing a wire material, deforming part of the wire material to be a ring shape, cutting off the part in the ring shape to obtain a ring-shaped wire material, and forging the ring-shaped wire material into a washer having a split defined by end surfaces at two opposite ends of the ring-shaped wire material.

The invention relates to a method for producing a flat spiral spring, in particular a spring sheet for covering a cooling area of a piston of internal combustion engines, said spring sheet being formed at least as an annular disk-shaped segment (12), wherein a strip-shaped material (23) is fed to a bending device (27) that comprises at least one drum (29), said drum rotating about a rotational axis (31), and the strip-shaped material (23) is supplied in a tangential alignment to the lateral surface (36) of the drum (29) such that a lateral wall (20) which determines the thickness of the strip-shaped material (23) rests against at least some sections of a contact surface (37) on the lateral surface (36) of the drum (29). The contact surface (37) of the drum (29) has a radius which substantially corresponds to an internal radius of the strip-shaped material (23) to be bent into the segment (12), and at least one deflecting device (32) is aligned at a distance to the drum (29) such that the strip-shaped material (23) is guided in a forced manner between the drum (29) and the deflecting device (32), and the strip-shaped material (23) is bent so as to follow the drum (29) by means of the deflecting device.

A method for producing a flat spiral spring formed as an annular disk-shaped segment, wherein a strip-shaped material is supplied in a tangential alignment to the lateral surface of the drum such that a lateral wall which determines the thickness of the strip-shaped material rests against some sections of a contact surface on the lateral surface of the drum. The contact surface of the drum has a radius which substantially corresponds to an internal radius of the strip-shaped material, and at least one deflecting device is aligned at a distance to the drum such that the strip-shaped material is guided in a forced manner between the drum and the deflecting device, and the strip-shaped material is bent so as to follow the drum by means of the deflecting device.

A method for producing a flat spiral spring formed as an annular disk-shaped segment, wherein a strip-shaped material is supplied in a tangential alignment to the lateral surface of the drum such that a lateral wall which determines the thickness of the strip-shaped material rests against some sections of a contact surface on the lateral surface of the drum. The contact surface of the drum has a radius which substantially corresponds to an internal radius of the strip-shaped material, and at least one deflecting device is aligned at a distance to the drum such that the strip-shaped material is guided in a forced manner between the drum and the deflecting device, and the strip-shaped material is bent so as to follow the drum by means of the deflecting device.

A steel strand (10) comprises a steel core wire (12). This steel core wire (12) is surrounded by steel layer wires (14) that are twisted around the steel core wire (12). The steel core wire (12) is covered with a thick corrosion resistant core coating (16) provided by strip cladding or by metal extrusion. The steel layer wires (14) are covered with a thin corrosion resistant layer coating (18) provided by a hot dip operation or by an electroplating or chemical plating process. The steel strand (10) is compacted so that said steel layer wires (14) have a non-circular cross-section and that the thick corrosion resistant core coating fills the interstices between the steel core wire (12) and the steel layer wires (14) in order to give the steel strand (10) an improved corrosion resistance and increased lifetime.

A method of manufacturing a washer capable of improving a material yield is provided. The method includes: a preparation step of preparing a longitudinal member which includes an upper corrugated portion and a lower corrugated portion including crest portions formed on at least one of an upper surface and a lower surface and valley portions continuous to the crest portions in the right-left direction; and a deformation step of deforming the longitudinal member such that the upper surface and the lower surface are arcuate as viewed in the direction from the front to the rear.

A method of manufacturing a washer capable of improving a material yield is provided. The method includes: a preparation step of preparing a longitudinal member which includes an upper corrugated portion and a lower corrugated portion including crest portions formed on at least one of an upper surface and a lower surface and valley portions continuous to the crest portions in the right-left direction; and a deformation step of deforming the longitudinal member such that the upper surface and the lower surface are arcuate as viewed in the direction from the front to the rear.

A method of manufacturing a washer capable of improving a material yield is provided. The method includes: a preparation step of preparing a longitudinal member which includes an upper corrugated portion and a lower corrugated portion including crest portions formed on at least one of an upper surface and a lower surface and valley portions continuous to the crest portions in the right-left direction; and a deformation step of deforming the longitudinal member such that the upper surface and the lower surface are arcuate as viewed in the direction from the front to the rear.