Process and apparatus for producing flat cable

A process for producing a flat cable comprising:

• parallel fused portions each having a predetermined length;
• and twisted pair portions, each having a predetermined length, provided alternately with the parallel fused portions, said twisted pair portions each being composed of a plurality of twisted pairs juxtaposed to each other or one another, said plurality of twisted pairs each being composed of two conductors, which are separately insulated by an insulative layer and are twisted together, said parallel fused portions each being composed of separately insulated conductors which extend from the twisted pair portion and are disposed side by side, adjacent insulated conductors in their respective insulative layers in the parallel fused portion being fused to each other to form the fused portion, said process comprising the steps of:
• feeding a plurality of insulated conductors, each comprising a conductor covered with an insulative layer, juxtaposed to each other or one another into a twister provided with twist ports, said twist ports being constructed so that, when the plurality of insulated conductors in their portion for constituting the twisted pair portion are passed therethrough, the twist ports are rotated to form the twisted pair portion, while when the plurality of insulated conductors in their portion corresponding to the parallel portion before fusion are passed therethrough, the rotation of the twist ports is stopped to permit the plurality of insulated conductors to be parallel aligned with the identical pitch;
• delivering the portion corresponding to the parallel portion before fusing from the twist ports to a mold provided at a predetermined position located proximately to a conductor output side of twist ports, said mold comprising a combination of two molds, an upper mold and a lower mold, each having a plurality of grooves for accommodating therein said plurality of juxtaposed insulated conductors;
• upon delivery of the portion corresponding to the parallel portion from the twist port to the position of the mold, accommodating the plurality of insulated conductors in their portion corresponding to the parallel portion within the plurality of grooves of the mold, and closing the upper and lower molds to form the parallel fused portion in the mold;
• performing a first travel of the mold in the same direction and speed as used in the travel of the plurality of insulated conductors, opening the upper and lower molds to release the formed parallel fused portion, and performing a second travel of the mold to return the mold to said predetermined position;
• and
• utilizing the period between the first travel of the mold and the second travel of the mold to form the next twisted pair portion in the twist port.