In a case of a mark left type, a slit is formed on a line side (slit side) of a joint portion. The slit is formed, for example, with a scroll saw. By the formation of the slit, a length of the joint portion in a direction orthogonal to an axial direction of a single ring is set to approximately 0.7 mm. In a case of a mark removed type, a slit and a slit are formed respectively on the line side (slit side) and a side opposite thereto of the joint portion. Those slits are formed, for example, with the scroll saw. By the formation of those slits, the length of the joint portion in the direction orthogonal to the axial direction of the single ring is set to approximately 0.8 mm.

A method for fabricating a fashion ring from a key is presented. The method includes supporting the key on first and second surfaces, forcing the key into a shaping aperture between the first and second surfaces with a round form, wrapping a first portion of the key around the round form with a first die, wrapping a second portion of the key around the round form with a second die, removing the wrapped key from the round form, and applying a finishing process to the wrapped key to form a fashion ring.

A method for fabricating a fashion ring from a key is presented. The method includes supporting the key on first and second surfaces, forcing the key into a shaping aperture between the first and second surfaces with a round form, wrapping a first portion of the key around the round form with a first die, wrapping a second portion of the key around the round form with a second die, removing the wrapped key from the round form, and applying a finishing process to the wrapped key to form a fashion ring.

A method and to a system for producing open or closed annular structural components made of light metal and alloys thereof, preferably of magnesium or magnesium alloys, having a two-dimensional or three-dimensional structure by means of extrusion, wherein the extruded profile exiting the die of the extrusion press is formed into a helical shape by way of one or more guide tools, and more particularly such that the ends of the helical shape are separated from the extruded strand in the region of the overlap and formed into a two-dimensional or three-dimensional structural component in a shaping device.

A method and to a system for producing open or closed annular structural components made of light metal and alloys thereof, preferably of magnesium or magnesium alloys, having a two-dimensional or three-dimensional structure by means of extrusion, wherein the extruded profile exiting the die of the extrusion press is formed into a helical shape by way of one or more guide tools, and more particularly such that the ends of the helical shape are separated from the extruded strand in the region of the overlap and formed into a two-dimensional or three-dimensional structural component in a shaping device.

A method for roll-forming a tubular member is provided. The method includes providing a roll-forming machine having a pair of rollers and a forming roller adjacent the pair of rollers. Further, cutting a strip of sheet metal to form a segment having free leading and trailing ends extending between a predetermined length; feeding the segment between the pair rollers; calculating the thickness of the segment via feedback from the pair of rollers; automatically adjusting the position of the forming roller in response to the determined thickness of the segment; advancing the segment between the pair of rollers and against the forming roller to form an annulus; and forming a weld joint between the free ends.

A method for roll-forming a tubular member is provided. The method includes providing a roll-forming machine having a pair of rollers and a forming roller adjacent the pair of rollers. Further, cutting a strip of sheet metal to form a segment having free leading and trailing ends extending between a predetermined length; feeding the segment between the pair rollers; calculating the thickness of the segment via feedback from the pair of rollers; automatically adjusting the position of the forming roller in response to the determined thickness of the segment; advancing the segment between the pair of rollers and against the forming roller to form an annulus; and forming a weld joint between the free ends.

A synchronizer ring for a synchronization unit of a manual transmission has a ring axis and is formed of a ring-shaped sheet-metal cone with a substantially constant sheet thickness. The ring-shaped sheet-metal cone has a cone-shaped radial outer side and an opposite radial inner side with a cone-shaped friction surface, wherein on its radial outer side the sheet-metal cone includes an integrally molded centering collar for radially centering the synchronizer ring relative to a synchronizer hub of the synchronization unit. The sheet-metal cone is deformed in the region of the centering collar and includes a first sheet portion with a residual thickness reduced as compared to the sheet thickness and axially adjacent a second sheet portion with a collar thickness which at least corresponds to the sheet thickness. The residual thickness of the sheet-metal cone is substantially constant in the first sheet portion.

An inexpensive ring spring having high strength and a method for producing the same, are provided. The ring spring can be obtained, for example, by raw material preparation, bending formation, welding, and disk formation performed in this order. The ring spring is formed to have no edge by welding two edge parts of the raw material, and has a welded metal part that is formed at the interface of the two edge parts of the raw material, and a welded heat-affected zone that is formed around the welded metal part and heated by welding, and exhibits tensile strength of 1000 MPa or more. Since the ring spring has sufficient tensile strength as a disk spring and a wave spring, quenching and tempering are not necessary. Furthermore, since the product can be prevented from being deformed due to quenching and tempering, dimensional accuracy of the product can be improved.

A method for fabricating a fashion ring from a key is presented. The method includes supporting the key on first and second surfaces, forcing the key into a shaping aperture between the first and second surfaces with a round form, wrapping a first portion of the key around the round form with a first die, wrapping a second portion of the key around the round form with a second die, removing the wrapped key from the round form, and applying a finishing process to the wrapped key to form a fashion ring.