US3732680A

US3732680A - Wire guide for a cabling machine

Info

Publication number: US3732680A
Application number: US00197326A
Authority: US
Inventors: M Barrier
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 1971-11-10
Filing date: 1971-11-10
Publication date: 1973-05-15
Anticipated expiration: 1990-05-15

Abstract

In accordance with an illustrative embodiment of the present invention, a high speed tubular strander is adapted for making armored cable through the provision of roller guide assemblies that are fixed to the strander tube at stations where the core changes direction of longitudinal travel. Each guide assembly has rollers that engage the periphery of the core and function to impart thereto a component of lateral motion so as to drive the core in reverse rotation to that of the tube to eliminate undesirable twist in the finished cable.

Description

0 limited States Patent 1191 1111 3,732,68 Barrier 1 May 15, 1973 [541 WIRE GUIDE FOR A CABLING 2,476,180 7 1949 Charles .57 9

MACHINE 2,723,525 11/1955 Blaisdell 3,407,587 l0 1968 M't h ll [751 Inventor: Miller Houston, 3,456,433 7/1969 1131:1121: ..57/58.34 x [73] Assignee: Schluinberger Technology Corporation New York Primary Examm er Donald E. Watkins Attorney-Emest R. Archambeau, Jr., et al. 22 F'] d: N 10 197 1 1 57 ABSTRACT l [2 1 App] No 197,326 In accordance with an illustrative embodiment of the v present invention, a high speed tubular strander is [52] US. Cl ..57/58.34, 57/5836 adapted for making armored cable through the provi- [5]] lint. Cl. ..D07b 3/12 sion of roller guide assemblies that are fixed to the [58] Field of Search ..57/9, 34 R,58.32, strander tube at stations where the core changes 57/5834, 58.36, 106, 138, 161, 166, 58.3, direction of longitudinal travel. Each guide assembly 59 has rollers that engage the periphery of the core and function to impart thereto a component of lateral mo- [5 6] References'Cited tion so as to drive the core in reverse rotation to that of the tube to eliminate undesirable twist in the UNITED STATES PATENTS finished cable 2,162,131 6/1939 Somerville ..57/58.36 X 6 Claims, 5 Drawing Figures 13 II 20 5 24 27 v29 21 5 v 15 WIRE GUIDE FOR A CABLING MACHINE This invention relates generally to tubular stranders, and more particularly to a new and improved high speed tubular strander having the capability for making armored electrical cable.

In the prior art, several basic types of machines have been used in the manufacture of armored cable, wire rope, and similar products where a number of wires are twisted in helical lays about a cable core. One fairly common device is the planetary strander where the bobbins containing the wires are actually rotated about the core. The bobbins are mounted in cradles that are driven by gear, chain or cam in such a manner their axes remain spatially fixed during movement around the core. Inasmuch as rotation of the bobbin can be controlled, this type of device has been used almost exclusively for making armored cable where torsion control is very critical to eliminate any twist in the wire strands or the core. Another machine is the rigid strander which operates basically the same as the planetary strander except that the cradles are rigidly mounted and are not permitted to rotate relative to the cage assembly. This type of machine is used primarily in the manufacture of cable having large wire strands where torque control is not essential.

Both the planetary and the rigid strander machines have the inherent disadvantage that the bobbins and cradles represent large rotating masses which appreciably limit the speeds at which these machines can operate. In actual practice, these machines might make 100 lays per minute, for example.

The tubular strander, on the other hand, is constructed in such a manner that the bobbins do not rotate about the core but are mounted in-line in gimballed cradle assemblies within a long cylindrical tube. The wire from each bobbin is brought to the outside and then longitudinally along the tube by wire guides to the front end of the tube where they pass over a preforming head and then through a closing eye as they are twisted over the core. Since the bobbins do not rotate about the core, the amount of rotating mass is appreciably reduced thereby enabling much greater rotational speeds. For example, the tubular strander might make 1000 lays per minute compared to 100 lays for the planetary or the rigid strander.

In the past, however, the tubular strander has been largely limited to smaller cable or wire rope manufacture and has not been useful in making armored cable because of the difficulty in passing the relatively large armor wires over the outside of the tube and returning. The wire torque associated with tubular stranders has also limited their application to products not requiring the stringent torque control that is desirable in armored cable making operations.

The general object of this invention is to provide a new and improved tubular strander capable of manufacturing armored cable at high speed operation.

This and other objects are attained in accordance with the concepts of the present invention through incorporation in a tubular strander of curved guides having rollers in contact with the core at points where the core changes directions of axial travel. The rollers are mounted in pairs and are inclined at an acute angle with respect to the axis of the cable. Thus as the core moves axially, the rollers impart a lateral component as well as an axial component of motion to the periphery thereof, with the overall effect being to drive the core in a rotational direction that is reverse to that of the tube to fully compromise any twisting action that would otherwise occur. The ratio of circumferential movement to axial movement imparted by the rollers to the core, for example, can be altered by adjusting the angle that the axis of each roller makes with the core. However, in a preferred embodiment, this angle is made equal to the arc tangent given by the circumference of the core divided by the lay length or pitch of the wire being stranded.

The present invention has other objects and advantages which will become more clearly apparent in connection with the following detailed description of the structure and operation of a preferred embodiment thereof, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a somewhat schematic view of a tubular strander that incorporates the principles of the present invention;

FIG. 2 is a detailed isometric view of a wire guide and mounting block; and

FIGS. 3-5 are fragmentary views showing the angular disposition of the rollers with respect to the wire or core.

Referring initially to FIG. 1, a high speed tubular strander is shown schematically as including an elongated tube or barrel 10 having a tapered section 11 at its rearward end connected to a hollow shaft 12 which is journaled for rotation in a bearing 13 that is mounted in a vertical strand 14. The forward end of the tube 10 is journaled for rotation in a bearing 15 mounted in a stand 16, and also has a tapered end section 17. Suitable means (not shown) are provided for rotating the tube 10 at high rpm as described above. The core 18 about which the wire strands are to be helically layed is fed in from a payoff spool 19 through the shaft 12 and brought through an opening 20 to the outside of the tube 10. From here the core 18 extends along the outside of the tube 10 through eyes, tubes or other typical guides to another opening 27 where it comes back into the tube It) and is made to pass out through the center of tapered section 17. Thus the core 18 enters and exits along the axis of rotation of the tube 10, and upon exit passes through a closing head 22 where the armor wires are positioned thereon, and the finished cable passes around a capstan assembly 23 to a take-up spool (not shown).

The tube 10 has a plurality of vertically disposed partitions 24 which mount, in gimbal fashion, a series of cradle assemblies 25 in-line with the rotation axis of the tube. The assemblies 25 are gravity biased by weights or the like to remain in substantially level altitude during rotation of the tube 10. The cradle assemblies 25 each carry a bobbin 26 containing a strand of armor wire 27, the wire being fed through a hollow cradle trunnion 28 and then through an opening 29 to the outside of the tube 10. The wires 25 fed along the outside of the tube 10 to its forward end where they pass through wire guides 30 and through a preforming head 31. After preforming the wires proceed into the closing eye 22 where they are positioned in helical lays over the core 15. For purposes of clarity the tube 10 is shown foreshortened in FIG. 1, however, it will be appreciated that in actual practice the tube is quite lengthy and contains a large number of bobbins containing the armor wires used for armored cable making operations.

As previously mentioned, the primary advantage of this type of machine lies in its capability for high speed operation. However, difficulties have been encountered in the past in connection with passing the wires and the core over the outside of the tube due to the sharp turns that were necessary in coming to the outside and returning. Moreover, a certain amount of undesirable torque was applied to the wire due to frictional engagement with the outside wire guides as the tube rotates. There was also an inherent tendency of the wires to cause the core to be twisted somewhat as they arelaid helically thereon at the closing head. These difficulties have heretofore largely limited this type of machine to the manufacture of smaller wire rope and cable, and to cable where stringent torque control is unnecessary.

In accordance with the principles of this invention, a plurality of wire drive guide assemblies 35 are mounted at the various stations on the machine where the core 18 changes direction of travel. Each wire drive guide assembly 35 serves two primary functions (1) to impart a reverse torque to the core to neutralize its tendency to be twisted in the direction of rotation of the tube 10, thereby enabling precise torque control, and (2) to provide a curved path of large radius for the core to avoid yielding that would otherwise result from too sharp bends.

Referring now to FIG. 2, the structural details of a guide assembly 35 will be explained in connection with its cooperative relationship to the core 18 of the cable, and it will be appreciated that the same or similar principles apply with respect to the armor wires. That is to say, the guide assemblies described below may be attached to the tube at points where the armor wires change direction of axial travel as shown schematically in FIG. 1. In any event, a mounting block 36 is adapted by suitable means to be secured in fixed position on the tube 10 and has a longitudinally extending inclined recess 37 that is sized to receive a guide beam 38. The guide beam 38 has a smoothly curved outer surface 39 into which are formed two series of spaced apart

pockets

40 and 41 located in alternating fashion, each pocket being adapted to receive a roller assembly 42. Each roller assembly 42 is constituted by a roller 43 (FIG. 5) that is mounted on a shaft 44 having screw threads 45 for attaching the roller assembly within a

respective pocket

40 or 41.

As shown in FIGS. 3-5, each roller 43 is mounted for rotation about an axis that is inclined to the side of a line perpendicular to the outer surface of the guide beam 38, preferably at a 45 angle, in order to provide a well defined path for the core 18 through the guide. Moreover, each roller 43 is inclined with respect to a plane that is perpendicular to the longitudinal axis of the core 18 by an acute angle 6. By virtue of the inclination of the roller 43 by the angle 0, it will be apparent that as the core 18 causes the roller to rotate by engagement therewith as it runs past the roller, the roller through frictional contact will impart a lateral component of motion to the periphery of the core. By choosing the correct value for the angle 6, the tendency of the core 18 to be twisted due to frictional forces as it passes longitudinally along the outside guides on the strander tube 10, or as the wires 27 are laid thereon at the closing head 22 can be precisely neutralized by an opposing torque. It has been found that a correct value for the angle 0 is the arc tangent given by the circumference of the core 18 divided by the lay length (pitch) of the armor wire being stranded.

In operation, as the core passes over a wire drive guide assembly 35, each roller 43 provides a point of support so that the virtual turn radius is large to avoid sharp bends or turns that would otherwise cause the wire to yield in an undesirable manner. Each roller 43 also imparts a lateral component of motion to the periphery of the wire or core which effectively drives it in a reverse rotation to that of the tube 10 to eliminate undesirable torque that has been associated wit prior stranders. Since stringent torque control can be had through use of the present invention, it is now possible to manufacture armored cable at the high speeds afforded by tubular stranders.

Since certain changes or modifications may be made by those skilled in the art without departing from the inventive concepts of the present invention, it is the aim of the appended claims to cover all such changes and modifications falling within the true spirit and scope of the present invention.

I claim:

1. Apparatus for use in a high speed tubular strander adapted to manufacture cable wherein armor wires are laid about a cable core that passes along a tortuous path through a rotating tube, comprising a roller guide assembly adapted to be fixed to said tube at a point where said core changes directions of axial travel, said guide assembly having a plurality of rollers adapted to engage the periphery of said core, each roller being mounted for rotation about an axis that is inclined with respect to the axis of said core so as to impart a lateral component of motion to said periphery tending to drive said core in a rotational direction opposite to that of said tube.

2. The apparatus of claim 1 wherein said rollers are mounted in pairs at spaced points along a guide beam having a curved outer surface.

3. The apparatus of claim 1 wherein the rotation axis of each roller is inclined with respect to the axis of said core by a principal angle whose tangent is given by the circumference of the core divided by the lay length of wire being laid about said core.

4. Apparatus for use in a high speed tubular strander adapted to manufacture cable wherein armor wires are laid about a cable core that passes along a tortuous path between the inside and the outside of a rotating tube, comprising: a mounting block adapted to be fixed to said tube at locations where said core changes directions of axial travel; an elongated guide beam fixed to said mounting block and having a curved outer surface; and a plurality of pairs of roller guides attached to said guide beam at spaced points therealong, each roller guide being inclined to the side of a line perpendicular to the surface of said guide beam in a manner to provide a curved travel path of large radius for said core, each roller guide further being inclined with respect to the longitudinal axis of said core so as to impart a lateral component of motion to the periphery of said core tending to drive said core in a rotational direction that is opposite to that of said tube to enable stringent control of torque during a cable making operation.

5. Apparatus according to claim 4 wherein each roller guide is inclined with respect to the axis of said core by a principal angle whose tangent is given by the circumference of the core divided by the lay length of wire being laid about said core.

6. Apparatus according to claim 5 wherein each roller guide is positioned partially within a pocket formed in the outer surface of said guide beam.