Method of and apparatus for making wire strand

Claim 3

A method according to claim 1 wherein equal percentage reductions in cross-sectional area are made in each of the two die elements.

Claim 4

Compacted strand comprising a central core wire and at least one layer of wires wound around the core wire and made by the method as claimed in claim 1.

Claim 5

Wire rope formed from a plurality of lengths of strand as claimed in claim 3.

Claim 6

Apparatus for making compacted strand comprising a central core wire and at least one layer of wires wound around the core wire comprising: 1. a stranding machine for forming individual round steel wires into uncompacted wound strand, comprising a central core wire and at least one layer of wires wound around the core wire, the machine comprising rotatable bobbins for carrying the wires, a closing die for receiving the wires from the bobbins and assembling the wires into said uncompacted strand, and means capable of braking the rotation of the bobbins, only to the extent of keeping the wires taut between the bobbins and closing die, 2. a reducing die adjacent to the closing die to receive the uncompacted strand emerging from the closing die and to deform and reduce the cross-section area of at least the outer wires of the strand thus to increase the fill factor of the strand, the reducing die consisting of two die elements spaced apart in the direction of strand advancement, each element being arranged to effect a percentage reduction in area of at least 10%. 3. means to lubricate the strand between the die elements, 4. means for drawing the wires off the bobbins and through the closing die and for drawing the strand through the reducing die, 5. the dies being such that the wires forming the strand are free to move relative to one another in the directions of their lengths throughout their passage from the bobbins to the exit from the reducing die through distances corresponding to the differences in length of the individual wires caused by drawing the strand through the reducing die thus to prevent bird-caging.

Claim 7

Apparatus for making compacted strand comprising a central core wire and at least one layer of wires wound around the core wire comprising: 1. a stranding machine for forming individual round steel wires into uncompacted wound strand, comprising a central core wire and at least one layer of wires wound around the core wire, the machine comprising rotatable bobbins for carrying the wires, a closing die for receiving the wires from the bobbins and assembling the wires into said uncompacted strand, and means capable of braking the rotation of the bobbins, only to the extent of keeping the wires taut between the bobbins and closing die, 2. a reducing die adjacent to the closing die to receive the uncompacted strand emerging from the closing die and to deform and reduce the cross-section area of at least the outer wires of the strand thus to increase the fill factor of the strand, the reducing die consisting of two die elements spaced apart in the direction of strand advancement, each element being arranged to effect a percentage reduction in area of at least 10%. 3. means to lubricate the strand between the die elements, 4. means for drawing the wires off the bobbins and through the closing die and for drawing the strand through the reducing die, 5. the dies being such that the wires forming the strand are free to move relative to one another in the directions of their lengths throughout their passage from the bobbins to the exit from the reducing die through distances corresponding to the differences in length of the individual wires caused by drawing the strand through the reducing die thus to prevent bird-caging.

Claim 8

Apparatus according to claim 5 wherein each die element is arranged to produce an equal percentage reduction in cross-sectional area of the strand entering the element.

Claim 9

Apparatus according to claim 5 wherein the or each reducing die element has an entrance throat with an angle of taper between 8° and 35°.