Conductor strand formed of solid wires and method for making the conductor strand

A method of making a conductor strand formed of solid wires, the conductor strand having a substantially circular cross-sectional configuration, the cross-sectional configuration having a size in the gage range from No. 20 AWG to No. 0000 AWG and comprising an inner layer consisting of six round wires helically applied about a central round wire, each wire of the inner layer having a first lay, and further comprising an outer layer consisting of six round third wires and six round fourth wires each disposed between a pair of third wires, the third and fourth wires being helically applied over the inner layer with a lay having the same length and running in the same direction as the first lay, comprising the steps of:

• providing a supply of round solid wires comprising thirteen (13) wires which includes a first wire having a diameter D.sub.1, six (6) second wires having a diameter equal to the diameter D.sub.1 and six (6) third wires having a diameter equal to the diameter D.sub.1 and including six (6) fourth wires each having a diameter D.sub.4 which is approximately seventy-three and two-tenths of a percent of the diameter D.sub.1 (D.sub.4 .apprxeq.0.732 D.sub.1);
• applying a first unit tension T.sub.1 of five and four tenths kilograms per square millimeter (T.sub.1 =5.4 Kg./mm.sup.2) to the first wire, a second unit tension T.sub.2 of four kilograms per square millimeter (T.sub.2 =4.0 kg./mm.sup.2) to each second wire, and a third unit tension T.sub.3 of three and two-tenths kilograms per square millimeter (3.2 Kg./mm.sup.2) to each third and fourth wire;
• passing all of the wires through a first lay plate to dispose the six second wires about the first wire and to dispose the six third wires and the six fourth wires about the six second wires;
• assembling the six second wires circumferentially about the first wire in a first layer;
• passing in a first axial direction the assembled second wires and first wire through a first closing die at a first location, the first closing die having a bore diameter C.sub.1 approximately equal to three times the diameter D.sub.1 (C.sub.1 .apprxeq.3D.sub.1) such that each second wire tangentially engages the first closing die to prevent circumferential movement of the wires with respect to the die without substantially changing the shape or diameter of the wires passing through the first closing die;
• twisting helically at the closing die at the first location the six second wires circumferentially about the first wire with a second lay which has a length greater than the first lay and which runs in the same direction as the first lay to form a core;
• passing the six third wires and the six fourth wires through a second lay plate to dispose the six third wires and the six fourth wires about the core;
• passing the core to a second location;
• assembling the six third wires and the six fourth wires circumferentially about the core before the core reaches the second location, the six fourth wires each being disposed between an adjacent pair of third wires;
• passing in the first axial direction all of the assembled wires through a second closing die at a second location, the second closing die having a bore diameter C.sub.2 approximately equal to 4.46 times the diameter D.sub.1 (C.sub.2 .apprxeq.4.46 D.sub.1) such that each of the third wires and each of the fourth wires are capable of tangentially engaging the second closing die to prevent circumferential movement of the third and fourth wires with respect to the die without substantially changing the shape or diameter of the third and fourth wires as the wires pass through the second closing die;
• twisting helically at the second closing die at the second location the six third wires and the six fourth wires circumferentially about the core with a lay having the same length as the second lay and having the same direction as the first lay to form a conductor strand having a lay which is equal to the second lay;
• passing the conductor strand from the second location to a third location;
• rotating the conductor strand about an axis of rotation Ar a first time as the wire passes from the second location to the third location to twist the wires in a first rotational direction at the first location and the second location;
• passing the conductor strand in a direction opposite to the first axial direction through a guide die, the guide die having a bore diameter C.sub.3 which is at least equal to the maximum diameter of the conductor strand having the second lay;
• rotating the fourth wires, the third wires and the second wires in the first rotational direction a second time aout the axis of rotation A.sub.r to simultaneously twist helically at the third location the six second wires, the six third wires, and the six fourth wires about the first wire in the same direction as the second lay to reduce the second lay to the first lay thereby forming a conductor strand having the first lay;
• and,
• securing the stranded conductor against untwisting.

A method of making an electric cable which includes a conductor strand formed of solid wires, the conductor strand having a substantially circular cross-sectional configuration, the cross-sectional configuration having a size in the gage range from No. 20 AWG to No. 0000 AWG and comprising an inner layer consisting of six round wires helically applied about a central round wire, each wire of the inner layer having a first lay, and further comprising an outer layer consisting of six round third wires and six round fourth wires each disposed between a pair of third wires, the third and fourth wires being helically applied over the inner layer with a lay having the same length and direction as the first lay, comprising the steps of:

• providing a supply of round solid wires including thirteen (13) wires which include a first wire having a diameter D.sub.1, six (6) second wires having a diameter equal to the diameter D.sub.1 and six (6) third wires having a diameter equal to the diameter D.sub.1 and including six (6) fourth wires having a diameter D.sub.4 which is in a range of sixty-eight percent to seventy-eight percent of the diameter D.sub.1, (0.68D.sub.1 .ltoreq.D.sub.4 .ltoreq.0.78D.sub.1);
• applying a first unit tension T.sub.1 to the first wire, a second unit tension T.sub.2 to each second wire, and a third unit tension T.sub.3 to each third wire and to each fourth wire, the unit tension T.sub.1 being greater than the unit tension T.sub.2, the unit tension T.sub.2 being greater than the unit tension T.sub.3 ;
• disposing the six second wires circumferentially about the first wire in a first layer;
• passing the wires to a first location;
• twisting helically at the first location the six second wires circumferentially about the first wire with a second lay having a length greater than the first lay and having the same direction as the first lay to form a core at the first location;
• passing the core to a second location;
• disposing the six third wires and the six fourth wires circumferentially about the core before the core reaches the second location, the six fourth wires each being disposed between an adjacent pair of third wires;
• twisting helically at the second location the six third wires and the six fourth wires circumferentially about the core with a lay having the same length as the second lay and having the same direction as the first lay to form a conductor strand having a lay which is equal to the second lay;
• passing the conductor strand from the second location to a third location;
• simultaneously twisting helically at the third location the six second wires, the six third wires, and the six fourth wires about the first wire in the same direction as the second lay to reduce the second lay to the first lay thereby forming a conductor strand having a first lay;
• securing the stranded conductor against untwisting;
• and,
• applying a layer of insulating material to the conductor strand;
• wherein the difference in diameter between the third wires and the fourth wires provides a substantially circular cross-sectional shape and in combination with the different levels of unit tension facilitates manufacture of the wire by accommodating relative longitudinal movement of the layers to block the formation of high strands and wire breaks.

A conductor strand of the type used in an electric cable, the conductor strand being formed of a plurality of round, solid wires, which comprises:

• a core having
• a first wire having a diameter D.sub.1 and a longitudinal axis A.sub.1,
• six second wires helically wrapped about the first wire with a first lay, the lay running in a first direction and having a first length, each second wire having a diameter D.sub.2 equal to the diameter D.sub.1 ;
• and,
• an outer layer of twelve wires helically wrapped about the core with a lay having the same length and direction as the first lay, the outer layer having
• six third wires wrapped helically about the core and spaced circumferentially one from the other to form parts of third wires and to leave a circumferential gap G between each pair of adjacent third wires, each third wire having a diameter D.sub.3 equal to the diameter D.sub.1,
• six fourth wires each disposed between a pair of associated third wires in the gap G between the third wires, each of the fourth wires having a diameter D.sub.4 which is in a range of sixty-eight percent (68%) to seventy-eight percent (78%) of the diameter D.sub.1 of said first wire, (0.68D.sub.1 .ltoreq.D.sub.4 .ltoreq.0.78D.sub.1);
• wherein at any section through the strand taken perpendicular to the axis A.sub.1 the strand has a substantially circular outside cross-sectional configuration and each fourth wire is spaced away from at least one of the adjacent pair of third wires leaving a minimum gap therebetween which is greater than zero to increase the flexibility of the wire and to facilitate manufacture of the wire.

A conductor strand of the type used in an electric cable, the conductor strand being formed of a plurality of round, solid wires formed of an electric conductor material, which comprises:

• a first wire having a longitudinal axis A.sub.1 and a cross-sectional shape which is round, the first wire having a diameter D.sub.1,
• an inner layer of six second wires disposed circumferentially about the first wire,
• each second wire having a cross-sectional shape which is round and which has a diameter D.sub.2 equal to the diameter D.sub.1,
• each second wire being helically wound about the first wire with a first lay, the first lay running in a first direction and having a first length, and,
• each second wire tangentially engaging the first wire and the adjacent pair of second wires;
• an outer layer of twelve solid wires disposed circumferentially about the inner layer, the outer layer having
• six third wires disposed circumferentially about the inner layer, each third wire having a cross-sectional shape which is round and which has a diameter D.sub.3 equal to the diameter D.sub.1, each third wire being helically wound about the inner layer with a lay having the same length and direction as the first lay, each third wire tangentially engaging a pair of adjacent second wires, and each third wire being spaced circumferentially from the circumferentially adjacent third wires leaving a circumferential gap G between each pair of third wires;
• six fourth wires, each fourth wire being disposed in an associated circumferential gap G with a lay having the same length and direction as the first lay and having a cross-sectional shape which is round and which has a diameter D.sub.4 which is in a range of sixty eight percent (68%) to seventy-eight percent (78%) of the diameter D.sub.1 of the first wire, (0.68D.sub.1 .ltoreq.D.sub.4 .ltoreq.0.78D.sub.1);
• wherein at any section through the strand taken perpendicular to the longitudinal axis A.sub.1 of the first wire, the fourth wire is spaced away from at least one of the third wires leaving a minimum gap therebetween which is greater than zero to increase the flexibility of the cable and to facilitate manufacture of the cable.

An electric cable which includes a conductor strand formed of a plurality of round, solid wires, which comprises:

• a core having
• a first wire having a diameter D.sub.1 and a longitudinal axis A.sub.1,
• six second wires helically wrapped about the first wire with a first lay, the lay running in a first direction and having a first length, each second wire having a diameter D.sub.2 equal to the diameter D.sub.1 ;
• an outer layer of twelve wires helically wrapped about the core with a lay having the same length and direction as the first lay, the outer layer having
• six third wires wrapped helically about the core and spaced circumferentially one from the other to form pairs of third wires and to leave a circumferential gap G between each pair of adjacent third wires, each third wire having a diameter D.sub.3 equal to the diameter D.sub.1,
• six fourth wires each disposed between a pair of associated third wires in the gap G between the third wires, each of the fourth wires having a diameter D.sub.4 which is in a range of sixty-eight percent (68%) to seventy-eight percent (78%) of the diameter D.sub.1 of said first wire, (0.68D.sub.1 .ltoreq.D.sub.4 .ltoreq.0.78D.sub.1);
• and,
• a layer of insulating material disposed about said third and fourth wires;
• wherein at any section through the strand taken perpendicular to the axis A.sub.1 the strand has a substantially circular outside cross-sectional configuration and each fourth wire spaced away from at least one of the adjacent pair of third wires leaving a minimum gap therebetween which is greater than zero to increase the flexibility of the wire and to facilitate manufacture of the wire.

An electric cable having a conductor strand which includes a plurality of round, solid wires formed of an electric conductor material, which comprises:

• a first wire having a longitudinal axis A.sub.1 and a cross-sectional shape which is round, the first wire having a diameter D.sub.1,
• an inner layer of six second wires disposed circumferentially about the first wire,
• each second wire having a cross-sectional shape which is round and which has a diameter D.sub.2 equal to the diameter D.sub.1
• each second wire being helically wound about the first wire with a first lay, the first lay running in a first direction and having a first length, and,
• each second wire tangentially engaging the first wire and the adjacent pair of second wires;
• an outer layer of twelve solid wires disposed circumferentially about the inner layer, the outer layer having
• six third wires disposed circumferentially about the inner layer, each third wire having a cross-sectional shape which is round and which has a diameter D.sub.3 equal to the diameter D.sub.1, each third wire being helically wound about the inner layer with a lay having the same length and direction as the first lay, each third wire tangentially engaging a pair of adjacent second wires, and each third wire being spaced circumferentially from the circumferentially adjacent third wires leaving a circumferential gap G between each pair of third wires;
• six fourth wires, each fourth wire being disposed in an associated circumferential gap G with a lay having the same length and direction as the first lay and having a cross-sectional shape which is round and which has a diameter D.sub.4 which is in a range of sixty eight percent (68%) to seventy-eight percent (78%) of the diameter D.sub.1 of the first wire, (0.68D.ltoreq.D.sub.4 .ltoreq.0.78D.sub.1);
• a layer of insulating material disposed about said third and fourth wires;
• wherein at any section through the strand taken perpendicular to the longitudinal axis A.sub.1 of the first wire, the fourth wire is spaced away from at least one of the third wires leaving a minimum gap therebetween which is greater than zero to increase the flexibility of the cable and to facilitate manufacture of the cable.