Importance

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Abstract

Apparatus for producing a helical wire coil which can be subdivided into discrete spiral binders for use in steno pads or other types of stationery products has a driven mandrel with a cylindrical intermediate section flanked by two frustoconical sections whose larger-diameter ends are adjacent to the respective axial ends of the cylindrical section. The wire to be coiled is fed into the inlet of a helical path which is defined by guide pins distributed around the sections of the mandrel. The inlet is adjacent to one of the frustoconical sections and the wire which is fed into the inlet advances along the helical path to be coiled during travel around the one frustoconical section, thereupon around the cylindrical section and finally around the other frustoconical section. The exposed surface of the cylindrical section may be grooved. The distance between the inlet of the helical path and the cylindrical section is less than the length of the cylindrical section, as considered in the axial direction of the mandrel. The other frustoconical section ensures that the convolutions of the coil can contract subsequent to advancement beyond the cylindrical section but remain coaxial with the mandrel.

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First Claim