MXPA99009089A - Multi-wire sz and helical stranded conductor and method of forming same - Google Patents

Abstract

Un conductor trenzado de alambres múltiples (10) es formado de un núcleo central desnudo (12), una capa de alambre trenzado SZ intermedia (14) enrollada sobre el núcleo y una capa exterior (L2) enrollada helicoidalmente sobre la capa intermedia SZ. Las capas intermedia y externa aseguran que el conductor trenzado de alambres múltiples (10) mantenga un sección transversal sustancialmente circular mientas que la capa externa helicoidal asegura la integridad mecánica de la capa intermedia SZ.

Description

CONDUCTOR BRAID HELICOIDAL AND MULTIPLE WIRES SZ AND METHOD TO FORM IT BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to the manufacture of braided cable and, more particularly, to multi-wire twisted wire and SZ stranded conductors and to the method for manufacturing same. Description of the Prior Art Compressed braided cable conductors are well known in the art. The examples are disclosed in U.S. Patent Serial Number 4,473,995, in U.S. Patent Serial Number 3,383,704, and in U.S. Patent Serial Number 3,444,684. Such cables are preferred over uncompressed cables or compacted cables for several reasons. Compressed conductors commonly have a fill factor of approximately 81% to 84%. The fill factor is defined as the ratio of the total cross section of the wires to the area of the circle surrounding the braid. Uncompressed cables require the maximum amount of insulation because the diameter of the cable is not reduced and because the interstitial slits or valleys between the outer braids are filled with insulation material. The common filler factors for these conductors are approximately 76%. On the other hand, compact drivers, while eliminating the aforementioned disadvantages, could have physical properties that are not desirable for specific applications. The common filling factors for these constructions range from 91% to 97%. The multi-wire compressed conductor strands are made in different configurations and by several different methods. Each method and configuration has advantages and disadvantages. One approach is to form the braid with a central wire surrounded by one or more helically layered wires. The braid is formed by twisting the wires of each layer around the central wire with a wire twisting machine. A reverse concentric braid is an example of a braid made by this method. Each layer of a reverse concentric braid has a reverse layer in successive layers and a greater length of layer with respect to the previous layer. In the case of a 1 9 wire conductor braid, it may be required to pass twice through a wire twisting machine to form the braid. An example of a known braid includes a passage for a 6-wire layer having, for example, a layer on the right hand side on a central wire and a second step for a layer of 12 wires having a layer on the left hand on the wire. first layer of six wires. The braid can also be formed in one step with machines having boxes rotating in opposite directions by applying both layers at the same time, but the productivity of said machines is very low.

A single layer conductor is a second example of a conductor braid having layers placed helically placed around the central wire. Each layer of a single-layer braid has the same layer address and the same layer length. As each layer has the same length and the same direction, the braid can be formed in a single step. As a result, productivity increases. Single layer braids are used in a variety of configurations and commonly for sizes up to and including 240 square millimeters. These braids can commonly be manufactured in a Planetary, Rigid, Tubular, Single Torque Machine and, more recently, the Double Torque Machine. The economic benefits of the Double Twist machine surpass all other production processes and is the preferred system for this product. Historically, the limitations of the process have limited its widespread use for some products. This occurs mainly due to the process of closing two stages and the accessibility of the finished product for conformation and training. With reference to Figure 1, one of the most commonly used layer conductors is a conductor S1 formed with 19 wires of the same diameter D. In said braid, the six wires 4 of the inner layer L1 and the twelve wires 6 of the outer layer L2 are wound on the core core wire 2 in the same manner and in a concentric pattern. Typically, a hexagonal pattern is formed (interrupted line H) and not the desired round configuration C. This hexagonal configuration presents many basic problems because circumscribed circle C creates six voids V. These voids are filled with insulation that requires more insulation for a thickness of minimum insulation compared to a true concentric braid. Experience has also shown that the wires at the corners tend to change position and return during extrusion. As a result of this problem, engineers in the conductor wire industry have been looking to develop conductor braids that maintain a circular cross-section and increase the uniformity of the conductor section. One approach is to try to place the twelve outer conductors such that they each have two wires 6a, 6b in the second layer L2 placed on the surface of one of the six wires 4 of the first layer L1. Said conductor S2, shown in Figure 2, is sometimes said to have a "soft body" construction that avoids the aforementioned problem with respect to conductor S1 in Figure 1. However, the "soft body" construction does not It is stable and can not be easily achieved commercially without considerably reducing the layers and. Therefore, the productivity of the machine. Additionally, any variation in the diameter of the wire or the tension in the wires can cause the braid of the conductor to change to the hexagonal configuration shown in Figure 1 which represents the stable construction of low energy. Another attempt to solve the problem has been to form a composite braid S3 in accordance with United States Patent 5 of North America Serial Number 4,471,161 and shown in Figure 3. This latter construction has the advantage of being stable, but the disadvantage to require wires 6c, 6d with different diameters D1, D2 in the second layer L2. However, in order to maintain a circular outer cross section, the diameters D1, D2, which are must select produce spaces or slits G between the wires into which the insulation can penetrate. A variation on this idea is shown in Figure 4 where the 7-wire (1 + 6) shroud is compressed, said compression allows the smaller diameter wires 6d to move radially towards in a degree that substantially eliminates the tangential spaces in the 12-wire layer L2. Another solution has been to use a combination of elements or round wires formed or shaped to ensure that the desired fill factor is obtained with a stable braid designed to minimize the area of outer space and optimize the use of insulation material. An example of a braid of this type uses a combination of 7"T" shaped elements with 12 round "O" shaped elements that provides a stable braid design. These constructions are shown in the publication _'.- > No. 211091 published by Ceeco Machinery Manufacturing Limited, on page 537-7. In this construction, the outer elements 11 or "O" wires are in contact with each other thus minimizing the slits or spaces and the fill factor is approximately 84%. In a configuration of this type "O / T / O", the outer wires are in contact with the flat surfaces of the inner layer "T" and have no tendency to collapse in the spaces or minimum slits therein. A modification of the braid mentioned above includes several degrees of compression of the outer round wires with the result that the range of filling factors can be increased from approximately 84 to 91%. As the inner layer of the 7 conductors is also compacted, the elements of the inner layer produce a substantially cylindrical outer surface with minimized or substantially eliminated interstitial grooves. Although this eliminates the aforementioned problem of the outer layer collapsing in the slits of the inner layer, said cables have filling factors that are very high for some applications. A twisted conductor design of a modified concentric compressed layer is disclosed in United States Patent Serial Number 5,496,969 issued to Ceeco Machinery Manufacturing Ltd., the transferee of the subject application. The conductor, in accordance with the above-mentioned patent, is formed of combinations of compressed wires having nominally equal diameters. The number of wires selected in any two adjacent layers is not divisible by a common integer other than the whole number one. To achieve such construction, the conductor in one or more of the layers may need to be formed in sectoral cross section configurations. However, to form the wires in this way, they have to be compressed inwards. However, the resulting increase in fill factor and reduction in outside diameter has not been acceptable for certain applications in some market segments. BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide a multi-wire twisted round or sector conductor that can be manufactured to eliminate the problems mentioned in the prior art while maintaining a high manufacturing efficiency.

Another object of the present invention is to provide a multi-wire braided round or sector conductor having desirable physical characteristics for a wide range of applications and to compare favorably with traditional concentric reverse-layer compressed braid conductors. Still another object of the present invention is to provide a multi-wire twisted round or sector conductor that maintains a circular cross section and prevents unwanted movements of wire braids from one layer to interstices or adjacent layer spaces that distort the section configuration desired outer circular cross-section of the resulting conductor.

Still another object of the present invention is to provide a multi-wire twisted round or sector conductor that can be rolled or shaped after the second twist that allows a roll and formed while maintaining the integrity of the construction without limitation for further processing. Yet another object of the present invention is to provide a multi-stranded stranded conductor that provides consistent and reliable cross-sectional configurations without the need to use braids or wires of different diameters or formed braids having other circular cross-sections. Still another object of the present invention is to provide a multi-wire braided conductor as in the above objects in which the manufacturing process is facilitated using wires of the same diameter in conjunction with a variety of braiding machines including a double twisting machine , twisting machines and drum rollers. Another additional object of the present invention is to provide a multi-stranded stranded conductor that reliably resolves the problem of deterioration of some conductors which assumes the "hexagonal" cross-sectional shape when the wires of the same diameter are braided with the same length of layer and with the same layer address. Yet another object of the present invention is to provide a multi-stranded stranded conductor that effectively provides a wide-layer tolerance for a wide range of conductor diameters. In order to achieve the above objects, as well as others will be apparent hereinafter, a multi-wire braid conductor in accordance with the present invention comprises a bare wire core. At least one intermediate layer SZ of bare wire is wound in said core. An outer layer of bare wire is helically wound on at least one winding layer SZ. In this way, said intermediate and outer layers ensure that the composite conductor maintains a circular outer cross section while said helical outer layer ensures the mechanical integrity of said at least one intermediate layer SZ. If n layers are wound on a core, at least one intermediate layer 1 to n-1 are layers wound SZ and the outer layer n is helically wound on the intermediate layers. The integer n can be any number commonly used in relation to stranded conductors. The method of forming a multi-wire stranded conductor in accordance with the invention comprises the steps of braiding at least one additional intermediate layer SZ consisting of a plurality of wires on a central core layer consisting of at least one wire. An outer helical layer is braided on the outermost SZ intermediate layer. In this way the outer and intermediate layers ensure that the composite conductor maintains a substantially circular cross section that introduces a text sector conformation while said outer helical layer ensures the mechanical integrity of at least one additional SZ intermediate layer. BRIEF DESCRIPTION OF THE DRAWINGS The above-mentioned and other additional aspects of the present invention will be more apparent from the following description and the accompanying drawings in which: Figure 1 is an illustrative end view of a braid of the prior art consisting of 19 wires of the same diameter, including a central wire, six wires of an inner layer and twelve wires of an outer layer, which are wound on the central wire, shown collapsed in a hexagonal pattern as a result of that the wires of the outer layer are received in the interstitial slits formed by the wires of the intermediate layer; Figure 2 is similar to Figure 1, but shows a 19-conductor braid known in the art as a "soft body" braid, in which pairs of adjacent wires in the layer more outside are placed on the surfaces of the wires of the intermediate layers; Figure 3 is similar to Figures 1 and 2, but shows a prior art construction of the type disclosed in U.S. Patent Serial Number 4,471,161, - > wherein the outer layer is formed of some wires having the same diameter as those of the inner layers and alternating with wires of smaller diameter in which the large diameter wires of the outer layer are received in the interstitial grooves of the wires. wires of the intermediate layer while the wires of smaller diameter are placed in the radially outermost crests of the intermediate wires; Figure 4 is similar to Figure 3 with the exception that the core core wire and the first six wire layer is compressed, through a die, to reduce the areas of the intermediate layer wires and provide surfaces substantially flat that are radially outwardly to allow the wires of smaller diameter in the outer layer to allow the wires in the outer layer to be closer to each other than in the braid shown in Figure 3; Figure 5 is a side elevational view, in partial perspective, of a multi-wire braid conductor in accordance with the present invention, showing successive layers cut and progressively separated to provide details of the construction; Figure 6 is a sectional view of the conductor shown in FIG.

Figure 5, taken along line 6-6; and Figure 7 is a schematic representation of a line including a double twist machine to produce the braid construction shown in Figures 5 and 6. DESCRIPTION OF THE PREFERRED MODALITY Referring now, more specifically to the Figures in FIGS. which like or identical parts are designated by the same reference numerals, and with reference first to Figures 5 and 6, a multiple stranded conductor, wires in accordance with the present invention is designated generally by reference numeral 10. The conductor 10 in the illustrated embodiment is formed of a single bare wire core 12. As will be apparent to those skilled in the art, and as described in United States Patent Serial Number 5,496,969, the central core 12 can also be in the form of a stranded conductor formed of multiple braids but is treated as a single conductor by the line of the machine used to form the conductor 10. An intermediate layer L1 is provided which is braided in an SZ configuration and is also formed of bare wire wound in the core 12. The process of inverted layer or twisted and twisted SZ has been become well known in the industry and the specific procedure used to establish the SZ braided configuration is not critical for the purposes of the present invention. Several techniques and machinery used to impart twisted and twisted SZ are well documented in the literature. See, for example, U.S. Patent Serial Number 4,813,223 and U.S. Patent Serial Number 4,288,976. Any suitable apparatus or technique can be used to impart SZ braid to the intermediate layers L1 with different degrees of advantage. In the illustrated embodiment, only an intermediate layer L1 SZ of bare wire is shown wound on the core 12. However, the invention contemplates at least one intermediate layer L1 SZ and numerous intermediate layers can be provided. It will be appreciated that for each intermediate layer L1 SZ there are inverses in the layer such that for each layer 16 transition region there is a region 18 on one side that exhibits a layer direction and a region 20 on the other side that exhibits a layer direction. an opposite layer direction. An important aspect of the present invention is that an outer layer L2 helically wound on the outermost SZ intermediate winding layer. With this construction, the braids or wires 12, 14 and 22 can have the same diameter. However, the intermediate layers SZ serve to effectively "trick" the adjacent layers of having a different layer length and to a certain degree a different layer direction. Thus, the external conductors 22, which are being wound uniformly and helically with a layer direction, can not be established in any of the interstices or spaces formed in the intermediate layer L1 but, instead, remain positioned around them. of the contour C which is defined by the outermost points of the conductors 14. In some cases, the intermediate layers L1 SZ may be slightly deformed or compressed by passing through a matrix or forming rollers. However, such deformation or formation does not need to be used in excess to maintain the SZ shape and prevent the braids or wires in the SZ layers from separating because the outer layer L2 wound as the outermost SZ layer ensures that the composite conductor maintains a substantially circular outer cross section and, at the same time, ensure the mechanical integrity of the intermediate layers SZ. Therefore, the outer layer L2 performs a number of functions. First, it functions as an outer layer of the conductor 10. However, as it is braided with a single layer direction, it rests on the outermost outer layer, around the contour C and ensures a circular outer contour C2. Additionally, the spiral layer L2 serves as a binder that fixes the individual intermediate layers SZ in order to avoid the need for binders frequently used with SZ cables. As will be evident from Figure 7, the outer braids of the helical layer L2 are in tangential contact with each other and all have the same diameter, thus minimizing the sizes of the interstitial voids V. This minimizes the amount of insulation required for the layer outer insulation 24. The multi-stranded stranded conductor according to the present invention can be formed using large recovery packages. As indicated, the configuration of the present invention avoids geometry problems. The present invention can also be used with sector conductors where space limitations require more compact conductors. An important benefit of the use of the present invention is the reduction in the use of rigid and tubular box brakers while allowing the use of double twisting machines. You can also use single-twist machines and drum rollers, as well as other high-speed braiding machinery. For example, the production of a conductor should be considered as an alternative to, for example, ASTM B786 / B787. These specifications cover a construction commonly referred to as a "simple combination layer". In this example, two diameters of wire were used to solve the hexagonal shape that commonly results when 19 wires of the same diameter are woven with the same layer length and the same layer direction, as exemplified in Figure 1. The use of the SZ principle applied to the six-wire layer would effectively provide a wide-layer tolerance simulating a different layer for the twelve-wire layer. The potential for this process also applies to wires for # 14 - # 10 gauge circuit as well as typical Class B braiding between caliber # 8 and caliber 4-0. The ability of the present invention to replace boxes of rigid structure, commonly boxes of six and twelve coils in 37 and / or 61 lines of wire, is an important benefit. In this example only the final wire layer of the braid has to be in "> constant spiral in the traditional sense, each pre-assembled layer would be assembled using the main SZ, an alternative to the above is the use of this technology operating with a simple torsion or drum-twisting machine. Wire wound on rails would be removed and the final coil would be made using the rotation of the single-twist or drum-twisting machine.The preferred package for this braid would be the coil or large-body packages manufactured using the 91.44 cm windings or 106.68 cm Referring to Figure 7, an outline of a typical manufacturing line for manufacturing the cable shown in Figures 5 and 6 is illustrated. Core 12, as suggested, may consist of a single wire or a wire Braided compound that is introduced along the line axis The coil or body packages (not shown) are provided and directed to carry the wires 14 of the first line. mere layer L1 to a closing matrix. An appropriate SZ unit or oscillator 30 is introduced downstream from the point where the lamp wires 14 were inserted and these wires are braided SZ over the core 12. Similarly, the external wires or braids 22 forming the outer layer L2 are they introduce current under the SZ 30 unit through an appropriate closing matrix to place these wires on the outer layer L1. The braids are placed in the desired orientations and advanced to the double twisting machine 32 which includes the initial input pulley 34, the arc 36 and the final or output 38 pulley. Once inside the double twisting machine and after if they have been twisted to the desired degree, a socket 40 is used to carry the wires that are then wound onto a spool or winder 42. When the braided conductors are to be formed sectorially, a sectorial winding area 44 is conveniently provided between the pulley end or outlet 38 and the outlet 40, the outlet 40 passes the wires through the sector rolling area 44 to impart the desired sectoral configurations. As indicated, individual conductors do not need to be compressed or excessively compacted. To avoid separation of the individual wires or braids from the SZ layers, the packing factors can be reduced compared to the packing factors associated with the conductors described in U.S. Patent Serial No. 5,496,969. Thus, the filling factors of the composite conductor can be no greater than 90% and can be reduced to no more than 85%. For many applications, the fill factor is preferably between 76-82%. Such low packing factors provide the additional benefits of keeping the outer diameters of the composite cables slightly larger than those that can be achieved with compacted or compressed conductors. This may be important for applications that require conductor terminations with electrical connectors that are designed to mate with conductors that have predetermined diameters. AdditionallyBy reducing the filling factors, the cables become more flexible, which is an advantage for some applications. Therefore, it will be appreciated that the construction of the conductors in accordance with the present invention provides significant flexibility and production efficiency. As the resulting conductor is extremely stable in its geometry and maintains the desired circular cross section at all times, regardless of the amount of compression or compaction, the degree of compression or compaction can be selected to meet other requirements for any given application, such as flexibility, external diameter, filling factor, etc. However, regardless of the degree of compaction or compression selected, the cable will maintain its circular outer shape and the amount of insulation applied to the cable will always be minimized. Although the preferred embodiment illustrates the use of circular braids to produce the conductor 10, this application is also applicable to the production of conductors with sector braids. The sectors are similar to standing shapes with different angles. The sectoral braid can have any angle, but the two most common are the sectors of 90 degrees and 120 degrees. Others include sectors of 60 degrees, 72 degrees, 100 degrees and 180 degrees among others. The known parameters that are necessary to manufacture sectorial braids are the same as the round braid except that the round braid is wound through a set or a series of sets of rollers to produce the desired profile.

The current practice is to produce an O / T / O construction and then to roll the round shape to the sectorial form immediately before the drive roll. The use of the O / SZ / O construction combined with the same sector winding process simulates the same constructions that are currently used in the industry and represents an ideal solution for segments of the industry that wish to use the economically convenient Double Twist process without have to change the construction of the established product. Thus, the introduction of the SZ braid layer provides the option of simulating a concentric inverse construction with a single layer accumulation. This allows the same geometry of an inverse concentric braid construction with, for example, the economically convenient Double Twist manufacturing process. Additionally, it introduces the potential of manufacturing a multi-layer conductor braid in parallel with extrusion systems. If an extruder 46 were to be placed on the line shown in Figure 7, it could be placed between the final closing point (at 22) and the intake of the isolated product which would preferably be a simple drum or twist machine or similar instead of a double-twist machine. Although this invention has been described in detail with particular reference to the preferred embodiments thereof, it will be understood that variations and modifications may be achieved within the spirit and scope of the invention as described herein and defined in the appended claims.

Claims (26)

1. CLAIMS 1. A multi-wire stranded conductor comprising a bare wire core; at least one intermediate layer SZ of bare wire wound on said core; and an outer layer of bare wire wound helically over said at least one wound SZ layer, wherein said outer and intermediate layers ensure that the composite conductor maintains a substantially circular outer cross section while said helical outer layer ensures the mechanical integrity of such at least one intermediate layer SZ.
2. 2. A multi-wire stranded conductor as defined in claim 1, wherein said central core comprises a single wire braid.
3. 3. A multi-wire stranded conductor as defined in claim 1, wherein an intermediate layer SZ is provided.
4. 4. A multi-wire braid conductor as defined in claim 1, wherein said outer, intermediate and core layers are formed of wire braids having circular cross sections.
5. 5. A multi-wire stranded conductor as defined in claim 4, wherein all said braids have the same diameter.
6. 6. A multi-wire braid conductor as defined in claim 1, wherein at least one of said layers is formed of wire braids having sector cross-sections.
7. 7. A multi-wire stranded conductor as defined in claim 1, wherein the fill factor of the composite conductor is not greater than 90%.
8. 8. A multi-wire stranded conductor as defined in claim 7, wherein the fill factor of the composite conductor is not greater than 85%.
9. 9. A multi-wire stranded conductor as defined in claim 8, wherein the fill factor is selected within the range of 76 to 82%.
10. 10. A multi-wire stranded conductor comprising a central core; and n layers wound on a core, at least one intermediate layer 1 to n-1 are layers wound SZ and the outer layer n is wound helically on said intermediate layers, such at least one outer layer and one intermediate layer ensure that the composite conductor maintain the mechanical integrity of the aforementioned at least one intermediate layer SZ.
11. A multi-wire braid conductor as defined in claim 10, wherein n = 2.
12. 12. A multi-wire braid conductor as defined in claim 10, wherein said outer, intermediate and core layers are formed of wire braids that have circular cross sections.
13. 13. A multi-wire stranded conductor as defined in claim 10, wherein all said braids have the same diameter.
14. A multi-wire braid conductor as defined in claim 10, wherein at least one of said layers is formed of wire braids having sector cross sections.
15. 15. A multi-wire stranded conductor as defined in claim 10, wherein the fill factor of the composite conductor is not greater than 90%.
16. 16. A multi-wire stranded conductor as defined in claim 13, wherein the fill factor of the composite conductor is not greater than 85%.
17. 17. A multi-wire stranded conductor as defined in claim 14, wherein the fill factor is selected within the range of 76 to 82%.
18. 18. A method for forming multiple wire stranded conductor comprising the steps of braiding at least one additional intermediate layer SZ consisting of a plurality of wires on a central layer consisting of at least one wire; and braiding a helical outer layer on the outermost outer layer, wherein said outer and intermediate helical layers ensure that the composite conductor maintains a substantially circular outer cross section while such a helical outer layer ensures the mechanical integrity of said at least one additional SZ intermediate layer.
19. 19. A method as defined in claim 18, where. an intermediate layer SZ is wound on such a central layer.
20. 20. A method as defined in claim 19, wherein all said layers are formed of circular wires having equal diameters.
21. 21. A method as defined in claim 18, further comprising the step of forming the wires in at least one of the layers to have sector cross sections.
22. A method as defined in claim 18, wherein the fill factor of the composite conductor is not greater than 90%.
23. 23. A method as defined in claim 22, wherein the fill factor of the composite conductor is not greater than 85%.
24. 24. A method as defined in claim 23, wherein the fill factor is selected within the range of 76-82%.
25. 25. A method as defined in claim 18, further comprising the step of twisting the composite braid into an outlet downstream of the station where the helical braid is applied.
26. 26. A method as defined in claim 25, further comprising the step of extruding a layer or coating of insulating material onto the composite conductor at a station between the station where the helical braid is applied and the socket.