Method and apparatus for manufacturing compact conductors

Abstract: A double-twist type compact conductor manufacturing apparatus is comprised of a supply device (2) for supplying strand conductors (12), a conductor twist machine (1), a converging compacting die (4) for converging and compacting a plurality of strand conductors (12), and a capstan (7) having a groove (9) adapted to form a converged compact conductor (8), as well as to send out the same. The converging compacting die (4) and the capstan (7) are disposed between the supply device (2) and the conductor twist machine (1) in that order. This conductor twist machine (1) is a double twist machine (1) for imparting a double twist to the converged compact conductor (8). This configuration of the apparatus serves to prevent not only the deformation of the profile of a twisted wire but also the breakage thereof.

Description: The present invention relates to a double twist machine functioning as a strander for manufacturing conductors for electrically conductive wires in wire manufacturing facilities for manufacturing electrically conductive wires for automobiles, appliances and so forth, and more particularly to a method and apparatus for manufacturing compact conductors. In manufacturing compact conductors on a conventional double twist machine 1 in which a compacting die 4a and a converging die 4b are provided on the inlet sides of a traction machine 6 and the double twist machine 1, concentric conductors of a single-layer structure have been compacted through one process, while concentric conductors of a multi-layer structure have been compacted on a one-compaction-for-one-layer basis through a plurality of processes. A double twist compact conductor manufacturing machine having a strander upstream of a drawing device is disclosed in Japanese Patent Public Disclosure Nos. 160515/1985 and 129704/1983. A method for manufacturing compact conductors and a double-twist type compact conductor manufacturing apparatus according to the preambles of claims 1 and 4 are disclosed in US-A-4 599 853. However, the above-mentioned prior art double twist machine 1 has difficulties in leading a wire through the compacting die 4a. On top of this, in a case where a defect such as strand separation or the like takes place in a twisted wire at a position prior to the compacting die 4a, the wire will break at such a position when the position reaches the compacting die 4a. This problem of wire breakage also takes place with concentric twisted wire with a multi-layer structure when the same are compacted through only one process. This is because it is impossible to exert uniform pressure on all the constituent strands of the wire when put through a single compaction, and hence strand separation takes place in the wire at the entry of the compacting die 4a, resulting in breakage of the wire. This problem can be solved by compacting the twisted wire on a layer-by-layer basis through two processes, but this type of manufacturing method reduces production efficiency. In addition, the construction of the prior art drawing devices was complicated. An object of the present invention is to provide a method and apparatus for manufacturing compact conductors in which a simply constructed drawing device and a converging compacting die are provided so that compaction is conducted in such a manner that final products have well-shaped profiles, free from deformations, and hence that no breakage takes place, and that wire leading is easily conducted. A method for manufacturing compact conductors according to the present invention is given in claim 1. An apparatus for manufacturing compact conductors according to the present invention is given in claim 4. Fig. 1 is a schematic front view of one embodiment of a double-twist type compact conductor manufacturing machine according to the present invention; Fig. 2 is an enlarged view of a capstan section of a drawing device; Fig. 3 is a partial enlarged side view showing the relationship between a peripheral groove and a converged compact twisted wire; and Fig. 4 is a schematic front view of a prior art double-twist type conductor manufacturing machine. With reference to Fig. 1, embodiments of a double-twist type compact conductor manufacturing method and an apparatus employing the same will be described. In a double-twist type compact conductor manufacturing device according to the present invention, a plurality of strand conductors 12 are supplied from each supply bobbin 2 through a lay plate 3 adapted to divide and arrange the strands in such a manner as to form an intended twisted wire construction into a converging compacting die 4, where converging and compacting of the strand conductors 12 is designed to be simultaneously conducted. A capstan 7 having a peripheral groove 9 and a drawing device 5 for driving the capstan 7 are provided on the outlet side of the converging compacting die 4. This drawing device 5 is designed to rotate the capstan 7 at such a rotational speed that the peripheral speed of the capstan 7 becomes equal to or greater than the wire drawing speed realised in a double twist machine 1, and it is also designed to operate in synchronism with the double twist machine 1. The capstan 7 has a peripheral groove 9 formed in its outer periphery. As shown in Fig. 3, this peripheral groove 9 is substantially as wide as the diameter of a die hole of the converging compacting die 4, which is substantially as deep as or deeper than the diameter of the same hole and has a semi-circular shaped bottom with the same curvature as that of the die hole. The positional relationship between the capstan 7 and a converged compact conductor 8 is shown in Fig. 2. The capstan 7 is located in such a position that the converged compact conductor 8 is accommodated in the peripheral groove 9 of the capstan 7, and the contact angle between the capstan 7 and the conductor 8 is set in such a manner as to generate an effective frictional resistance (u) therebetween. The capstan 7 is also designed to be driven so as to rotate idly, relative to the converged compact conductor 8. This allows the rotational force of the double twist machine 1 to twist strands to be transmitted from a twist port 16 to the converging compact die 4. In other words, a twist is imparted to the converged compact conductor 8 at a twist initiating section 13 on the outlet side of the capstan 7 and at a position on the inlet side of the capstan 7. As in the case of a prior art double twist machine, the compact conductor 8 is imparted a double-twist once it is fed into the double twist machine 1 from the twist port 16, and is then taken up on a take-up reel 15 via a drawing machine 6 provided inside the double twist machine 1. As shown in Fig. 2, the resistance caused by the converging compacting die is reduced as described below. Assuming that T0 represents a force necessary to draw the compact conductor through the converging compacting die, ϑ representing a contact angle between the capstan and the converged compact conductor, and u representing a frictional resistance between the same capstan and conductor, the relationship between the force T0 and a tension T1 on the outlet side of the capstan 7 is given as T1 = T0 e-uϑ, and hence , T1 < T0. Thus, T1 becomes lower than T0. Normally, a tension T2 inside the double twist machine is double the tension T1 outside the same, given as T2 = 2 x T1, however, since Ti is reduced by the capstan of the drawing machine, T2 is prevented from exceeding the breaking tension of the converged conductor, thus making it possible to perform twisting and compacting strands outside the double twist machine. However, the profile of a converged and compacted wire will be put out of shape if a flat capstan is used. To eliminate such a risk, a groove is formed in the periphery of a capstan as shown in Fig. 2. As a result of this, the converged and compacted wire is brought into contact with the sides and bottom of the groove, as shown in Fig. 3, and the profile of the wire is thereby securely maintained. In addition, since the rotation of the twist machine is designed to be transmitted to the converging compacting die, reverse rotation of the strands being twisted is prevented from occurring on the surface of the wire compacted by means of the converging compacting die, thus making it possible to obtain a similar compact conductor to the one obtainable by a conventional method in which compaction is effected inside the double twist machine. In addition, concentric compact conductors with multi-layer structure can also be obtained by the same method used in obtaining concentric compact conductors with a single-layer structure. As described above, the double-twist type compact conductor manufacturing apparatus according to the present invention is provided with the drawing device between the double twist machine and the strand conductor supplying device, the lay plate and the converging compacting die. This drawing device has the capstan, the peripheral speed of which, is equal to or greater than the pulling speed of the drawing device disposed inside the double twist machine and which is interlocked with the rotation of the double twist machine so as to operate in synchronism therewith to rotate at high speed. This capstan has the peripheral groove formed in the outer periphery thereof through which the coverged compact conductor is designed to pass while in contact with the groove. The capstan is, as mentioned above, disposed between the converging compacting die and the double twist machine in such a manner that the converged compact conductor passing through the groove thereof is fed into the double twist machine in a horizontal fashion. The drawing machine disposed outside of the double twist machine is located at such a position that a predetermined contact angle is formed relative to the converged compact conductor. With the present invention, since the compacting die is disposed outside of the double twist machine, leading strands through the die is easily accomplished. In addition, even conductors with a multi-layer structure can be manufactured through one process as in the case of conductors with a single-structure by utilizing the manufacturing facilities for the latter. Moreover, the double twist machine of the present invention is secured to operate to exhibit its 100 % capacity without having to reduce its rotation speed. Thus, the apparatus and method for manufacturing compact conductors according to the present invention ensures double the productivity as when compared with prior art compact conductor manufacturing apparatus and methods.

Claims: A method for manufacturing compact conductors, comprising the steps of: supplying a plurality of conductor strands (12) from conductor supply device (2); converging and compacting said plurality of strands together to form a converged compact conductor (8) by feeding the said plurality of strands into a converging and compacting die (4) downstream of said supply device (2); feeding said compact conductor (8) about a capstan; and imparting a twisting force to said compact conductor (8) by feeding said compact conductor from said capstan (7) downstream to a twist machine (1) characterised in that the capstan (7) has a peripheral groove (9) formed therein with a semi-circular shaped bottom complementary to that of the compact conductor (8) such that the compact conductor (8) is received in the groove downstream of the converging and compacting die (4) and such that the shape of the compact conductor is preserved. A method as recited in claim 1, characterised by the additional step of separating the plurality of strands in a diverging manner in a predetermined configuration by passing the plurality of strands (12) through a lay plate (3). A method as recited in claim 1, characterised in that the capstan (7) is rotatably driven, and the compact conductor (8) is fed to the twist machine (1) at a speed dependent on the speed of rotation of the capstan (7). A double-twist type compact conductor manufacturing apparatus comprising: a supply device (2) for supplying a plurality of conductor strands (12); converging and compacting means (4), disposed downstream of said supply means, for converging and compacting said plurality of strands so as to form a converged compact conductor (8); a capstan (7) being mounted downstream of said converging and compacting means: and twist means, disposed downstream of said capstan, for imparting a twisting force to said compact conductor characterised in that the capstan (7) has a peripheral groove (9) formed therein for receiving the compact conductor (8) within it so as to feed the compact conductor (8) further downstream, in which the groove (9) has a semi-circular shaped bottom complementary to that of the compact conductor (8) in order to preserve the shape of the compact conductor (8) as it is fed further downstream. An apparatus according to claim 4, characterised in that it further comprises a lay plate, mounted on the inlet side of the converging compacting die (4), for separating said plurality of conductor strands (12) in a diverging manner in a predetermined configuration. An apparatus according to claim 4, characterised in that it further comprises means for rotatably driving the capstan (7), the compact conductor (8) being fed to the twist means (1) at a speed dependent on the speed of rotation of the capstan (7).

Inventors: IURA KAZUO, SAKA KAZUHITO, TSUJI KAZUNORI, IURA, KAZUO, SAKA, KAZUHITO, TSUJI, KAZUNORI
Applicants: SUMITOMO WIRING SYSTEMS, SUMITOMO WIRING SYSTEMS, LTD.
Application year: 1989
Main classification: H01B13
IPC codes: H01B13, D07B3, D07B7