Method and apparatus for manufacturing toroidal cores

A method of manufacturing a toroidally-wound first ring inside a second ring, comprising the steps of:

• providing opposed first and second walls, the first wall having a continuous arcing surface comprising contiguous first and second surface portions of differing curvature, the second wall having a continuously arcing surface, the first and second walls defining a cavity, and a second ring disposed between the first and second walls, a portion of the second ring within the cavity;
• passing the leading edge of a ribbon of strip stock material through the second ring;
• sliding the ribbon along the arcuate surface of the second wall;
• bringing the leading edge of the ribbon into sliding contact with the first surface portion of the first wall;
• sliding the ribbon along the second surface portion of the first wall;
• and
• passing the leading edge of the ribbon through the second ring an additional plurality of times to form a first ring having a plurality of ribbon layers between the first and second walls.

A method of manufacturing a toroidally-wound first ring inside a second ring, comprising the steps of:

• providing oppositely facing first and second arcuate wall surfaces;
• passing the leading edge of a ribbon of strip stock material through the second ring;
• sliding the ribbon along the second arcuate wall surface;
• sliding the ribbon along the first arcuate wall surface;
• passing the leading edge of the ribbon through the second ring an additional plurality of times to form a first ring having a plurality of ribbon layers between the first and second arcuate wall surfaces;
• and
• controllably separating the first and second arcuate wall surfaces.

An apparatus for manufacturing a toroidal core comprising:

• a fixture having a passageway through which a ribbon of strip stock material extends, said future having separable first and second parts, said first and second fixture parts respectively having first and second arcuate walls, said first and second arcuate walls at least partially defining an expandible cavity, said passageway in communication with said cavity, said cavity including a space in which a bobbin element having a through-hole is disposed, said passageway opening into said space, said passageway opening substantially aligned with the bobbin element through-hole, whereby the ribbon extends from said passageway, through the bobbin element through-hole, and into said cavity;
• means for feeding the ribbon through said passageway and within said cavity;
• and
• means for elastically curving the ribbon into a spiral shape inside said cavity, whereby the ribbon is spirally wound through the bobbin element through-hole;
• and
• wherein at least one of said first and second arcuate cavity walls is controllably moved between a first position in which said cavity has a first size and a second position in which said cavity has a second size larger than said first cavity size.